JPH06323113A - Engine having variable valve timing mechanism - Google Patents

Abstract

PURPOSE:To secure maximum output and improve fuel consumption performance by providing two intake valves, a cam for low speed, and a cam for high speed, and switching modes between a non-interlocking mode and an interlocking mode in respect to first and second rocker arms which drive first and second intake valves, and a third rocker arms corresponding to the cam for high speed. CONSTITUTION:A cam 12 for low speed and a cam 13 for high speed open and close first and second intake valves 3, 2. A first rocker arm 6 drives the intake valve 3, while being in contact thereto. A second rocker arm 14 drives the intake valve 2, while being in contact thereto. A third sub-rocker arm 15 indirectly drives the intake valves 2, 3. Modes are changed over correspondingly to rotation conditions of an engine between a non-interlocking mode wherein the third rocker arm 15 is not interlocked with the first and second rocker arms 6, 14, and an interlocking mode wherein the motion of the third rocker arm 15 is transmitted to the first and second rocker arms 6, 14. It is thus possible to realize efficient combustion in a wide range, improve fuel consumption performance in a low speed condition, and obtain sufficient output in a high speed condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine having a valve operating system that opens and closes an intake valve in response to the rotation of a crankshaft, and more particularly to an engine having two intake valves depending on the rotational speed state of the engine. The present invention relates to an engine with a variable valve timing mechanism capable of switching the operating states of these two intake valves.

[0002]

2. Description of the Related Art In recent years, the improvement of the fuel consumption rate (fuel consumption) of an engine such as an automobile is not only from the viewpoint of effective use of energy resources, but also from the viewpoint of protecting the global environment by reducing harmful exhaust gas from the engine. It is also strongly requested by However, on the other hand, for example, an engine for an automobile is required to have a certain acceleration performance and a high-speed performance as well as a sufficient output characteristic as a practical vehicle from a low-speed rotation range to a low-speed rotation range to a high-speed rotation range. ing.

By the way, in order to promote the improvement of fuel consumption, it is necessary to secure a sufficient torque in the low speed rotation range so as to be sufficiently practical in the low speed rotation range. On the other hand, in order to secure sufficient acceleration performance and high speed performance, it is necessary to secure sufficient torque in the high speed rotation range. However, generally, there is a conflict between securing torque in the low speed rotation range and securing torque in the high speed rotation range, and it has been difficult to realize both at the same time.

Therefore, in an OHC (overhead camshaft) type engine used in automobiles, etc., a valve operating system for opening and closing intake valves and exhaust valves is operated to open / close timing of these intake / exhaust valves and a lift amount at opening. A device has been developed in which the torque in the low-speed rotation range and the torque in the high-speed rotation range can be sufficiently secured by changing the torque in accordance with the rotation state of the engine.

In such a device (that is, a variable valve timing mechanism), for example, a camshaft is equipped with a high speed cam and a low speed cam, and either the high speed cam or the low speed cam is provided. By selecting and using it, the opening / closing timing of the intake / exhaust valve corresponding to the operating state can be obtained. The low speed cam is, for example, as shown in FIG.
As shown by the curve 3a ', a cam profile capable of obtaining the opening / closing timing corresponding to the low speed operation is provided, and the high speed cam is designed for high speed operation as shown by the curve 3b' in FIG. It has a cam profile that can get the corresponding opening and closing timing. That is, the high-speed cam has a longer valve opening time and a larger valve lift amount than the low-speed cam.

As a mechanism for selecting the high-speed cam and the low-speed cam, in the rocker arm type cam device, the valves are driven by the high-speed cam by connecting or disconnecting the rocker arms to each other. Alternatively, the valve is driven by a low speed cam to obtain the opening / closing timing of the intake / exhaust valve corresponding to the operating state.

As a result, the low speed cam provides a torque characteristic as shown by a curve 3a 'in FIG. 18, and the high speed cam gives a torque characteristic as shown by a curve 3b' in FIG. Is obtained. Then, with the engine speed Ne _{0 at} which these characteristic curves intersect as a switching point, a low speed cam is selected in a lower speed rotation range than this, and a high speed cam is selected in a higher speed rotation range than this, thereby making a wide range. Torque characteristics with high torque and little fluctuation can be obtained in the engine speed range.

However, in the variable valve timing mechanism as described above, only two stages, a low speed stage as indicated by reference numeral 3a 'and a high speed stage as indicated by reference numeral 3b', can be switched, so that a sufficiently wide engine rotation is possible. There is a limit to obtaining a flat torque characteristic with high torque and small fluctuation in several ranges. In other words, with only two stages, low speed and high speed, in order to obtain high torque in a wide engine speed range, the maximum torque of the low speed stage is shifted to the side where the engine speed is lower, and the maximum torque of the high speed stage is increased. It is conceivable that the engine speed is shifted to a higher engine speed side. However, in this case, the torque tends to decrease in the region near the engine switching point rotation speed Ne ₀ , and it becomes difficult to obtain a flat torque characteristic.

Therefore, there has been proposed a device which can be switched to three stages of a low speed stage, a medium speed stage and a high speed stage. For example, FIGS. 19 to 22 show a variable valve timing mechanism disclosed in Japanese Patent Laid-Open No. 3-229906. As shown in FIGS. 19 to 22, a low speed cam 3a 'having a cam profile for low speed operation and a high speed cam 3b' as a driving member having a cam profile for high speed operation are arranged in parallel. ing. The characteristics of the cam profiles for low speed operation and high speed operation are set in the same manner as those shown by curves 3a 'and 3b' in FIG. 17, for example.

On the other hand, the low speed cam 3 is attached to the rocker shaft (arm shaft) 9'which is arranged in parallel with the cam shaft.
A primary rocker arm 4'driven by a'and a secondary rocker arm 13'driven by a high speed cam 3b 'are arranged in parallel. Primary rocker arm 4 '
Is rotatably attached to the arm shaft 9 ', but is also rotatable integrally with the arm shaft 9'by a lock mechanism R'.

The arm portion of the primary rocker arm 4'is provided with a shaft 6'on which a roller bearing (roller with bearing) 5'is mounted. The upper part of the roller bearing 5'is a low speed cam 3a '.
Is engaged with. That is, the primary rocker arm 4 '
Receives the driving force from the low speed cam 3a 'via the roller bearing 5'and the shaft 6'.

An adjusting screw 7 ', which is appropriately adjusted in position and fixed by a nut 8', is attached to the tip of the primary rocker arm 4 '. The valve stem upper end 1a 'of the valve 1'is engaged.
The valve stem upper end 1a 'is urged obliquely upward to the right in FIG. 22 by the valve spring 2'.

Therefore, the tip of the primary rocker arm 4'is swung in the vertical direction in FIG. 22 by the rotation of the low speed cam 3a ', and the valve 1'is driven vertically by the adjusting screw 7'. . On the other hand, in the arm part of the secondary rocker arm 13 ',
A shaft 14 'equipped with a roller bearing (roller with bearing) 15' is provided, and the upper portion of the roller bearing 15 'is engaged with the high speed cam 3b'. That is, the secondary rocker arm 13 'receives a driving force from the high speed cam 3b' via the roller bearing 15 'and the shaft 14'.

The secondary rocker arm 13 'is also pivotally supported by the rocker shaft 9', but the secondary rocker arm 13 'is always rotated integrally with the rocker shaft 9'by a half-moon key 12' interposed therebetween. It is fixed to. In addition, the secondary rocker arm 13 '
The lower end surface (that is, the lower surface of the roller bearing 15) on the swinging end side of the support spring (lost motion spring) 16
Cylinder head 17 'through piston 16' with a '
The urging force of the support spring 16a 'acts as a restoring force when the secondary rocker arm 13' swings.

Therefore, when the high speed cam 3b 'rotates, the rocker shaft 9'will always rotate repeatedly at the same time when the secondary rocker arm 13' swings.
By the way, the above-mentioned lock mechanism R'is configured as follows. That is, as shown in FIG. 19, a pin hole 9b 'extending in the radial direction of the shaft 9'is formed in the pivotal support portion of the primary rocker arm 4'of the rocker shaft 9', and this pin hole 9b 'is formed. The lock pin 10 'is loosely inserted.

The lock pin 10 'can be projected outward from the rocker shaft 9'by a pin drive mechanism P, and the lock pin 10' is provided on the inner circumference of a pivotal support portion of the rocker arm 4'to the rocker shaft 9 '. Is formed with a pin lock hole 4a 'into which the lock pin 10' can be fitted. By the way, the pin drive mechanism P of the lock pin 10 'is configured as follows. That is, a hydraulic passage 9a 'extending along the axis of the rocker shaft 9'is provided in the central portion of the rocker shaft 9', and an oil groove 10a 'is formed in the outer periphery of the central portion of the lock pin 10' to form an oil groove 10a '. From the outer peripheral surface of the lock pin 10 'to the axial center portion, and the hydraulic pressure of the hydraulic passage 9a' is controlled by the oil groove 10a 'and the hydraulic pressure supply hole. 10b '
It is adapted to be supplied to the rear end side of the lock pin 10 'via the.

A large diameter portion 10c 'is formed on the outer periphery of the rear end portion of the lock pin 10', and the large diameter portion 1 is formed in the pin hole 9b '.
A large diameter hole for sliding 0c 'and a small diameter hole for sliding the upper part of the lock pin 10' are formed. And the pin hole 9
Step b'from the small diameter hole to the large diameter hole of b'and the lock pin 1
A spring 1 is provided between the stepped portion of the large diameter portion 10c 'of 0'.
1'is interposed to urge the lock pin 10 'toward the rear end side.

As a result, when the hydraulic pressure is not supplied from the hydraulic passage 9a ', the lock pin 10' is driven to the rear end side, and the curved end face at the rear end is the inner circumference of the rocker shaft insertion hole 4b 'of the primary rocker arm 4'. When the lock pin 10 'is engaged with the surface or comes very close to it, the tip of the lock pin 10' is retracted inward from the outer peripheral surface of the rocker shaft 9 ', and the primary rocker arm 4'is fixed to the rocker shaft 9'. It will not be done.

On the other hand, when the hydraulic pressure is supplied from the hydraulic passage 9a ', the hydraulic pressure is supplied to the rear end side of the lock pin 10', and the large diameter portion 10c 'of the lock pin 10' is connected to the front end side and the rear end side. Lock pin 1 due to the differential pressure due to the difference in pressure receiving area
The driving force of 0'acts, and this driving force acts on the spring 11 '.
The lock pin 10 'enters into the pin lock hole 4a' of the primary rocker arm 4 '.

As a result, the lock pin 10 'and the pin lock hole 4a' are fitted, the primary rocker arm 4'and the rocker shaft 9'are fixed, and the primary rocker arm 4'is rocked integrally with the rocker shaft 9 '. Move. The rocker shaft 9'of the primary rocker arm 4 '
The axial position of is held by the snap ring 19 'and the thrust spring 18'.

In such a mechanism, for example, the curve shown in FIG.
As indicated by d, output pressure increases with engine speed
Use an engine pump that
While giving the changing hydraulic pressure to the above valve operating system,
Can be activated. That is, engine rotation
The first number of switching revolutions N₁Both intakes in the following range a
Both valves open and close for low speed. The engine speed is the first cut
Replacement speed N₁If it exceeds, the second switching speed N₂Since
In the lower range b, one intake valve opens and closes for high speed and the other intake valve opens.
The air valve opens and closes for low speed. Furthermore, the engine speed is the second
Switching speed N ₂In the above range c, both intake valves
Open and close for high speed.

As a result, the torque characteristics of the three stages of the low-speed stage, the medium-speed stage, and the high-speed stage in the respective rotational speed regions are shown by t ₁ , t ₂ , and t ₃ , and in the wide rotational speed region of the engine. Large torque, smooth and flat torque characteristics can be obtained. By the way, as described above, by switching the opening / closing timing of the intake valve, the opening time and the valve lift amount by the low speed cam and the high speed cam, while securing the acceleration performance and the high speed performance while using the low speed rotation range of the engine. Although low fuel consumption can be realized, such a method has a limit in improving fuel consumption and reducing harmful exhaust gas.

Therefore, a lean burn engine has been proposed in recent years as a means for reducing harmful exhaust gas while significantly improving the fuel efficiency of the engine. In such a lean-burn engine, the air-fuel ratio A / F of the air-fuel mixture is increased so that sufficient combustion energy can be obtained with a small amount of fuel.
However, if such leaning of the air-fuel mixture is promoted, the combustion speed is lowered and the ignitability is deteriorated when the temperature exceeds a certain condition, resulting in unstable combustion.

By the way, in order to realize the rapid combustion of the engine, it is necessary to promote the mixing of the fuel and the air and to increase the speed of flame propagation after ignition. As a most effective means for this purpose, it is considered that swirl (vortex flow) is generated to increase the flow velocity of the air-fuel mixture in the cylinder. However, in order to generate a strong swirl, there is no choice but to reduce the cross-sectional area of the suction port, and as a result, suction resistance increases and the output of the engine decreases. Also, in a four-valve engine with two intake valves and two exhaust valves,
It is difficult to generate swirl while maintaining engine output. Conversely, if intake air is made to flow from one intake port that is eccentric to the cylinder axis,
Easy to generate swirl.

Therefore, in a valve operating system with a variable valve timing mechanism having two stages, a low speed stage and a high speed stage, one of the two intake valves is stopped as a low speed stage and only one valve is used for intake. Have been developed. In other words, the camshaft is
7 has a cam (valve drive cam) having a characteristic for driving the intake valve with a characteristic shown by 3a 'or 3b and a cam (valve rest cam) close to the base circle, and one of the two intake valves is The switching mechanism can switch between a state in which the valve drive cam is driven and a state in which the valve stop cam is stopped. The other of the two intake valves has no switching mechanism and is always driven by the valve drive cam.

With such a structure, in the high speed stage, both intake valves are driven by the valve drive cam, and in the low speed stage, one of the two intake valves is stopped according to the valve stop cam and the other is driven by the valve drive cam. can do.
According to this, in the low-speed stage, while the swirl is generated, the mixture of fuel and air is promoted, and the air-fuel mixture is distributed in a layered manner, so that the fuel-rich air-fuel mixture can be unevenly distributed in the vicinity of the spark plug. . Then, the speed of flame propagation after ignition can be increased, and lean combustion is realized.

[0027]

By the way, in the case of the two-stage variable valve timing mechanism as described above, in which the intake is performed by only one valve in the low speed stage,
Since one valve drive cam is used to drive the valve, there is only one valve opening / closing characteristic when the intake valve is opened / closed.

Therefore, if the valve opening / closing characteristic is set for low speed as shown by the curve 3a 'in FIG. 17, for example,
During high speed rotation, both intake valves open and close with low speed opening / closing characteristics, so sufficient torque characteristics cannot be obtained in the high speed rotation range. For example, when mounted on an automobile, the engine can rotate at a high speed sufficient for practical use. Performance cannot be obtained. Conversely, if this valve opening / closing characteristic is set for high speed as shown by the curve 3b 'in FIG. 17, for example, one of the two intake valves will be in a closed state during low speed rotation, and the other will open / close with this high speed opening / closing characteristic. To do. With this high-speed opening / closing characteristic, the valve opening time is long and the valve lift amount is large. Therefore, if the fuel supplied to the combustion chamber is saved, the fuel concentration becomes too lean and appropriate combustion is difficult to perform.

Therefore, it is conceivable to combine the above-mentioned three-stage variable valve timing mechanism (see FIGS. 19 to 23) with this one-valve driving system at low speed. That is, FIG.
One of the low speed cams 3a ', 3a' shown in FIG. 0 is formed as a valve stop cam close to the base circle, and in the low speed stage, one of the intake valves is stopped according to this valve stop cam and the other is operated at low speed. It is driven according to the working cam 3a '. Further, in the medium speed stage, the drive system of one intake valve is switched and driven according to the high speed drive cam, and the other is driven according to the low speed cam 3a '. In the high-speed stage, the drive system of the other intake valve is also switched so that both intake valves are driven according to the high-speed drive cam.

As a result, at the time of high speed rotation, both of the two intake valves open and close with the opening / closing characteristics for high speed, so that the high speed rotation performance of the engine which is sufficient for practical use can be obtained, and at the time of low speed rotation, only one intake valve can be used. Since the open / close drive is performed with the open / close characteristic for low speed, the swirl flow can be used to save the fuel supplied to the combustion chamber, and to perform the appropriate combustion while keeping the fuel concentration to the extent that it does not become too lean.

However, in the case of such a three-stage structure, at the time of medium speed rotation, one intake valve has a high-speed opening / closing characteristic, and the other intake valve has a low-speed opening / closing characteristic, so that they open and close with different characteristics. Such opening and closing of the two valves in different modes makes it difficult to control the fuel supply timing and the like, and may also impair the stability of combustion.

Further, by switching between the low-speed stage and the medium-speed stage, one of the intake valves is switched from the rest to the high-speed opening / closing at once, so that the change in intake becomes violent near this switching point and a smooth engine output characteristic It may be difficult to obtain. The present invention has been proposed in view of the above problems, and it is possible to secure a sufficiently large and smooth engine output characteristic in a wide rotation range from a low speed rotation range to a high speed rotation range, while significantly reducing fuel consumption. It is an object of the present invention to provide an engine with a variable valve timing mechanism capable of achieving various improvements.

[0033]

Therefore, an engine with a variable valve timing mechanism according to the present invention as set forth in claim 1 is
A low speed cam that rotates in response to the rotation of the crankshaft of the engine with two intake valves, a first intake valve and a second intake valve, and a cam profile for low speed valve timing, and a low speed cam. A high-speed cam that includes a cam profile for high-speed valve timing including a cam profile for valve timing and that rotates in response to rotation of the crankshaft; and a rocker shaft pivotally supported at a required portion of the engine, A first opening / closing drive for opening and closing the first intake valve, which is provided so as to rotate around the rocker shaft, but does not directly contact the low speed cam and the high speed cam. A rocker arm and a low speed roller that can contact the low speed cam can be swung corresponding to the cam profile of the low speed cam, and
A second intake valve that abuts the second intake valve to open and close the second intake valve
A rocker arm, a third rocker arm having a high-speed roller abutting against the high-speed cam and swinging in response to the cam profile of the high-speed cam, and a second rocker arm linked to the first rocker arm. The first mode switching means capable of switching between the non-coordination mode in which the locker arm is not operated and the cooperation mode in which the third rocker arm is operated, and the third rocker arm.
Second mode switching means capable of switching between a non-cooperative mode in which the rocker arm is not linked to the rocker arm and a linked mode in which the rocker arm is linked, and states of the first mode switching means and the second mode switching means according to the rotation state of the engine. It is characterized by having a control means for controlling.

In the engine with variable valve timing mechanism according to the present invention as defined in claim 2, in addition to the structure according to claim 1, both the second rocker arm and the third rocker arm are attached to the rocker shaft. A first piston chamber rotatably mounted on the rocker shaft, the first mode switching means being formed on the rocker shaft, and having an opening exposed on the outer peripheral surface of the rocker shaft; and the side of the second rocker arm. A first recess formed in the first piston chamber and aligned with the opening of the first piston chamber when the relative phase between the second rocker arm and the rocker shaft is in a predetermined state; and the rocker shaft in the first piston chamber. Of the rocker shaft, the one end of which is inserted so as to be movable in a direction orthogonal to the axis of the rocker shaft and one end of which is projected from the outer peripheral surface of the rocker shaft and is fitted into the first recess and the one end of which is the rocker And a first drive mechanism that drives the first piston between the projecting position and the retracted position. At the same time, the second mode switching means is formed on the rocker shaft and has a second piston chamber having an opening exposed at the outer peripheral surface of the rocker shaft, and the third rocker arm is formed on the side of the third rocker arm. A second recess that is aligned with the opening of the second piston chamber when the relative phase of the rocker arm and the rocker shaft is in a predetermined state, and is orthogonal to the axis of the rocker shaft in the second piston chamber. A protruding position where one end of the rocker shaft is inserted so as to be movable in the direction and the one end of the rocker shaft is protruded from the outer peripheral face of the rocker shaft, and the one end is not protruded from the outer peripheral face of the rocker shaft. When A second piston that can be taken, is characterized by being configured to include a second drive mechanism for driving between the exit projecting the second piston position and the storage position.

Further, in the engine with a variable valve timing mechanism of the present invention according to claim 3, in addition to the configuration according to claim 2, the first drive mechanism causes the first piston to move the first piston to the storage position side or First biasing means for biasing to the projecting position side and hydraulically driving the first piston to the projecting position side or the storage position side against the first biasing means. And a first oil pressure supply means capable of supplying a required oil pressure into the first oil chamber when the engine is in a required rotation state. Drive mechanism for urging the second piston toward the storage position side or the protruding position side, and the second piston against the second urging means. A second oil chamber formed to be hydraulically driven to the protruding position side or the storage position side and the engine are required. It is characterized by being configured to include a second hydraulic pressure supply means capable of supplying the required oil pressure to the oil chamber of the second when the rotational state.

According to a fourth aspect of the present invention, there is provided an engine with a variable valve timing mechanism according to the third aspect, wherein the first urging means and the second urging means include the first urging means and the second urging means. Both the first piston and the second piston are urged toward the storage position side, and the first hydraulic pressure supply means is required in the first oil chamber when the engine is in the medium speed and high speed rotation states. And the second hydraulic pressure supply means is set to supply a required hydraulic pressure into the second oil chamber when the engine is in a high speed rotation state. Is characterized by.

In the engine with a variable valve timing mechanism according to the present invention of claim 5, in addition to the configuration of claim 4, both the first hydraulic pressure supply means and the second hydraulic pressure supply means are provided. It is characterized in that an engine pump driven by the engine is used as a hydraulic pressure source. Also,
According to a sixth aspect of the present invention, there is provided an engine with a variable valve timing mechanism according to the first aspect, in addition to the configuration of the first aspect, the control means has a rotational speed range of the engine in a low speed range, a medium speed range, or a high speed range. Is set to control the states of the first mode switching means and the second mode switching means depending on whether the engine is in the range, and when the engine is in the low rotation speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is set to a non-coupling mode in which the second rocker arm is not linked to the first rocker arm, and the third rocker arm is set to the first and the first mode. A two-valve low-speed operating state in which the first intake valve is closed and the second intake valve is opened / closed in accordance with the cam profile of the low-speed cam by setting the non-coupling mode in which the second rocker arm is not linked. When the engine is in the medium speed range, the second mode switching means and the second mode switching means are used to drive the second mode.
Of the first intake valve by setting the rocker arm of the first rocker arm to the first and second rocker arms in the linkage mode and setting the third rocker arm to the non-coupling mode in which the rocker arm is not linked to the first and second rocker arms. And both of the second intake valves are opened and closed in correspondence with the cam profile of the low speed cam to operate in a two-valve low speed mode, and when the engine is in the high speed rotation range, the first mode switching means and the first mode switching means The second rocker arm is set to a linking mode in which the second rocker arm is linked to the first rocker arm and the third rocker arm is set to a linking mode in which the first and second rocker arms are linked to each other through the second mode switching means. So that both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the high-speed cam so as to be in a two-valve high-speed operating state. It is characterized in that it is a constant.

Further, in the engine with variable valve timing mechanism according to a seventh aspect of the present invention, in addition to the structure according to the sixth aspect, the first intake valve and the second intake valve are provided in a downstream portion of an intake passage of the engine. Fuel injection means for injecting fuel toward both sides of the intake valve, and fuel injection guide means for deflecting fuel injected from an injection hole of the fuel injection means to the side of the second intake valve, And a fuel injection guide switching unit that operates the fuel injection guide unit when the first intake valve is closed and stops the fuel injection guide unit when the first intake valve operates. I am trying.

According to the eighth aspect of the present invention, in addition to the structure of the seventh aspect, the engine with a variable valve timing mechanism is provided in the intake passage from an upstream portion to a downstream portion of the intake passage. An intake air bypass passage and an opening / closing valve for opening and closing the intake air bypass passage are attached, and the downstream end of the intake air bypass passage is connected to the fuel injection guide means. The injection guide means is configured to inject the intake air guided by the intake bypass passage in a required direction to deflect the fuel injected from the injection hole toward the second intake valve side. The on-off valve is used as the switching means.

Further, in the engine with a variable valve timing mechanism of the present invention according to claim 9, in addition to the structure according to claim 1, the third rocker arm includes the first rocker arm and the second rocker arm. It is characterized by being installed between.

[0041]

In the engine with variable valve timing mechanism according to the first aspect of the present invention, the control means controls the states of the first mode switching means and the second mode switching means in accordance with the rotational state of the engine. . As a result, a non-coupling mode in which the second rocker arm is not linked to the first rocker arm is set through the first mode switching means, and the third rocker arm is connected to the first and second rocker arms through the second mode switching means. When the non-coordination mode in which the second rocker arm is not linked is set, neither the movement of the second rocker arm nor the movement of the third rocker arm is transmitted to the first rocker arm, and the second rocker arm and the third rocker arm are not transmitted. There is no linkage with the rocker arm.

Therefore, although neither the movement of the low speed cam nor the movement of the high speed cam is transmitted to the first rocker arm,
The second rocker arm swings according to the cam profile for the low speed valve timing of the low speed cam while abutting the low speed roller to the low speed cam to move the corresponding intake valve to the low speed valve timing. Open and close with.

Further, a linking mode for linking the second rocker arm to the first rocker arm is set through the first mode switching means, and the third rocker arm is set to the above-mentioned third mode through the second mode switching means. When the non-coordination mode in which the first and second rocker arms are not linked is set,
The movement of the second rocker arm is transmitted to the first rocker arm. However, the third rocker arm does not cooperate with the above-mentioned first and second rocker arms.

Therefore, the movement of the low speed cam is transmitted to the first rocker arm through the second rocker arm, and both the first rocker arm and the second rocker arm have the low speed valve of the low speed cam. It swings according to the timing cam profile, and opens and closes the corresponding intake valves at low speed valve timing. Further, a linking mode for linking the second rocker arm to the first rocker arm is set through the first mode switching means, and the third rocker arm is linked to the first and the third rocker arms through the second mode switching means. When the link mode for linking the two rocker arms is set, the second rocker arm, the third rocker arm, and the first rocker arm swing together.

Then, the second rocker arm, the third rocker arm, and the first rocker arm are provided with a cam profile for high speed valve timing including a cam profile for valve timing at low speed. In response to the movement of the intake valve, it swings integrally according to the cam profile for high speed valve timing, and the corresponding intake valves are opened and closed at the high speed valve timing.

In the engine with variable valve timing mechanism according to the second aspect of the present invention, in order to bring the first mode switching means into the link mode, the first drive mechanism is used to set the first piston chamber. One end of the first piston of the second rocker shaft is projected from the outer peripheral surface of the rocker shaft to
Of the rocker arm into the first recess in the protruding position. This causes the second rocker arm to rotate about the rocker shaft through the engagement of the first piston and the first recess.

In order to bring the first mode switching means into the non-coupling mode, one end of the first piston in the first piston chamber is projected from the outer peripheral surface of the rocker shaft through the first drive mechanism. Set it to a storage position that does not allow it. This disengages the first piston from the first recess and allows the second rocker arm to rotate with respect to the rocker shaft.

In order to bring the second mode switching means into the linked mode, one end of the second piston in the second piston chamber is moved from the outer peripheral surface of the rocker shaft through the second drive mechanism. The third rocker arm is projected so as to be in the projecting position fitted in the second recess of the third rocker arm. This causes the third rocker arm to rotate about the rocker shaft through the engagement of the second piston and the second recess. In order to put the second mode switching means in the non-coupling mode, the second drive mechanism is used to prevent the one end of the second piston in the second piston chamber from protruding from the outer peripheral surface of the rocker shaft. To This disengages the second piston from the second recess and allows the third rocker arm to rotate with respect to the rocker shaft.

In the engine with variable valve timing mechanism according to the third aspect of the present invention, the first drive mechanism and the second drive mechanism operate as follows. In the first drive mechanism, when the first hydraulic pressure supply means does not supply the required hydraulic pressure into the first oil chamber, the first piston is moved by the first biasing means to the storage position side or It is urged toward the protruding position.

Further, when the engine is in a required rotation state, the first hydraulic pressure supply means supplies a required hydraulic pressure into the first oil chamber. Then, the first piston is hydraulically driven to the protruding position side or the storage position side against the biasing force of the first biasing means. Therefore, if the first piston is in the retracted position, it is driven to the protruding position,
If the piston is in the projecting position, it is driven to the retracted position.

In the second drive mechanism, when the second hydraulic pressure supply means does not supply the required hydraulic pressure into the second oil chamber, the second piston is stored by the second biasing means. It is urged toward the position side or the protruding position side. Further, when the engine is in the required rotation state, the second hydraulic pressure supply means supplies the required hydraulic pressure into the second oil chamber. Then, the second piston is hydraulically driven to the protruding position side or the storage position side against the biasing force of the second biasing means. Therefore, if the second piston is in the retracted position, it is driven to the projecting position, and if the second piston is in the projecting position, it is driven to the retracted position.

In the engine with a variable valve timing mechanism according to the present invention as set forth in claim 4, when the engine is in a low speed rotation state, the first hydraulic pressure supply means and the second hydraulic pressure supply means are connected to the first hydraulic pressure supply means. The required hydraulic pressure is not supplied to the oil chamber and the second oil chamber. Therefore, the first
The first piston and the second piston are both in the retracted position by the urging force of the first urging means and the second urging means.

This disengages the first piston from the first recess and puts the second rocker arm into a non-coupling mode rotatable with respect to the first rocker arm. And the second piston disengages from the second recess and the third rocker arm is in a non-coupling mode rotatable relative to the first and second rocker arms. Become.

Further, when the engine is in the middle speed rotation state, the required hydraulic pressure is not supplied from the second hydraulic pressure supply means to the second hydraulic chamber, but from the first hydraulic pressure supply means. A required hydraulic pressure is supplied to the first oil chamber.
Therefore, the second piston is in the retracted position due to the urging force of the second urging means, while the first piston is in the projecting position due to the hydraulic pressure in the first oil chamber.

As a result, the first piston is engaged with the first recess, and the second rocker arm is brought into the state of the linkage mode in which the second rocker arm is linked with the first rocker arm, and the second rocker arm is brought into the linkage mode.
The piston is no longer engaged with the second recess,
The rocker arm is in a non-coupling mode in which the rocker arm is rotatable with respect to the first and second rocker arms. Further, when the engine is in a high-speed rotation state, a required hydraulic pressure is supplied from the first hydraulic pressure supply means and the second hydraulic pressure supply means to the first oil chamber and the second oil chamber.

Therefore, the first piston and the second piston
Of the second oil chamber and the second oil chamber, respectively.
Due to the oil pressure in the oil chamber, it is in the protruding position. As a result, the first piston engages with the first recess, the second rocker arm is brought into a linking mode in which it links with the first rocker arm, and the second piston By engaging the second recess, the third rocker arm is also in the linking mode in which it links with the first and second rocker arms.

In the engine with a variable valve timing mechanism according to the fifth aspect of the present invention, the first hydraulic pressure supplying means and the second hydraulic pressure supplying means both hydraulically operate the engine pump driven by the engine. Supply hydraulic pressure as a source. In the engine with a variable valve timing mechanism according to the sixth aspect of the present invention, the control means determines whether the rotational speed range of the engine is in a low speed range, a medium speed range, or a high speed range. The states of the first mode switching means and the second mode switching means are controlled.

Then, when the engine is in the low speed range, the second rocker arm is brought into the non-coupling mode in which the second rocker arm is not linked to the first rocker arm through the first mode switching means and the second mode switching means. At the same time, the third rocker arm is set to the non-coupling mode in which the third rocker arm is not linked to the first and second rocker arms. As a result, the one-valve low speed operating state is achieved in which the first intake valve is closed and the second intake valve is opened / closed in accordance with the cam profile of the low speed cam.

When the engine is in the medium speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is brought into a linkage mode in which the second rocker arm is linked to the first rocker arm, and the third rocker arm is linked to the first and second portions. The non-coordination mode is set so that the rocker arm of is not linked. As a result, a two-valve low-speed operating state is established in which both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the low-speed cam.

When the engine is in the high speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is brought into a linkage mode in which the second rocker arm is linked to the first rocker arm, and the third rocker arm is linked to the first and second portions. The link mode is set to link to the rocker arm of. As a result, a two-valve high-speed operating state is established in which both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the high-speed cam.

In the engine with variable valve timing mechanism according to the present invention described in claim 7, when the first intake valve is closed, the fuel injection guide switching means switches the fuel injection guide means to operate. To be Therefore, when the fuel injection means injects fuel from the injection hole toward both sides of the first intake valve and the second intake valve in the downstream portion of the intake passage of the engine, the fuel injection is performed. The fuel injected from the injection hole is deflected to the side of the second intake valve by the guide means.

Therefore, fuel is not injected into the first intake valve which is closed. Further, when the first intake valve is in operation, the fuel injection guide switching means switches the fuel injection guide means to stop. For this reason,
Fuel injection means, in the downstream portion of the intake passage of the engine,
When the fuel is injected from the injection hole toward both sides of the first intake valve and the second intake valve, the fuel injected from the injection hole is directly injected into the first intake valve and the second intake valve. Supplied on both sides of the intake valve.

In the engine with variable valve timing mechanism according to the present invention as described above, the idle rotation speed adjusting means adjusts the idle rotation speed of the engine while opening and closing the intake bypass passage through the opening / closing valve. When the first intake valve is closed, the on-off valve is opened, and a part of the intake air is guided to an intake bypass passage provided from the upstream portion to the downstream portion of the intake passage.

Then, the intake air introduced into the intake bypass passage is injected from the downstream end of the intake bypass passage through the fuel injection guide means, and the fuel injected from the injection hole is supplied to the side of the second intake valve. Deflected to. In the engine with a variable valve timing mechanism according to the present invention as set forth in claim 9, the third rocker arm includes the first rocker arm and the second rocker arm.
Between the third rocker arm and the first rocker arm and between the third rocker arm and the third rocker arm.
The respective distances between the rocker arm and the second rocker arm can be shortened, and the torsional deformation and the like between them can be suppressed.

[0065]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 12 show an engine with a variable valve timing mechanism as a first embodiment of the present invention.
1 is a perspective view of the valve operating system, FIG. 2 is a sectional view showing the variable valve timing mechanism, FIG. 3 is a sectional view showing the variable valve timing mechanism, and FIG. 4 is a schematic sectional view of the intake passage portion. 5, FIG. 5 is a cross-sectional view of an essential part of the intake passage portion, FIG. 6 is a view showing an air injection port member provided in the intake passage portion, and FIG.
8 is a diagram showing the output characteristic of the present engine, FIG. 9 is a diagram showing the valve lift state thereof, and FIGS. 10-12 are diagrams showing the operation of the variable valve timing mechanism. In addition, FIG.
16 shows an engine with a variable valve timing mechanism as a second embodiment of the present invention, FIG. 13 is a sectional view showing the variable valve timing mechanism, and FIGS. 14 to 16 are views showing the operation of the variable valve timing mechanism. Is.

First, the first embodiment will be described. The valve operating system of this embodiment is provided with a first intake valve 3 and a second intake valve 2 as a pair, as shown in FIG. A valve train is configured to open and close the intake valves 2 and 3. This valve train is directly driven by a base circular cam (hereinafter referred to as base circle) 10 and cams 12 and 13 which rotate in response to rotation of an engine crankshaft, and these cams 12 and 13. Rocker arms 14 and 15 and a rocker arm 6 indirectly driven via the rocker arm 14 or 15.

The base circle 10 and the cams 12 and 13 are both provided on the cam shaft 11 which rotates in conjunction with the rotation of the crankshaft of the engine. The cam 12 is a low-speed cam having a cam profile for low-speed valve timing, and the cam 13 is a high-speed cam having a high-speed valve timing cam profile. They have the same base circle diameter. The cam profiles of the low speed cam 12 and the high speed cam 13 have valve lift characteristics as shown in FIG. 9, and the cam profile of the high speed cam 13 is the same as that of the low speed cam 12. It is set to include.

The first rocker arm 6 is a main rocker arm that is in contact with the intake valve 3 and is directly involved in the opening / closing operation of the intake valve 3. Also, the second and third rocker arms 1
Reference numerals 4 and 15 are rocker arms with rollers.
The second rocker arm 14 is a main rocker arm that contacts the intake valve 2 and is directly involved in opening / closing driving of the intake valve 2. The third rocker arm 15 includes the intake valves 2, 3
Is a sub-rocker arm indirectly involved in opening / closing driving of the intake valves 2 and 3 without abutting against.

The main rocker arm 6 is provided integrally with the rocker shaft 16 as shown in FIG. The rocker shaft 16 is pivotally supported by a bearing portion 1A provided on a cylinder head or the like (not shown) of the engine, and the main rocker arm 14 can swing together with the rocker shaft 16. The main rocker arm 6 is provided with a screw mounting portion 6B at its swinging end portion 6A, and an adjusting screw 22 that comes into contact with the stem end portion of the intake valve 3 is screwed into this mounting portion 6B. . 22A is an adjusting nut.

Further, as shown in FIG. 1, a contact surface 6C capable of contacting the base circle 10 is provided at an intermediate portion of the main rocker arm 6, and a hydraulic piston mechanism 17 as a second mode switching means described later is provided. Alternatively, when the hydraulic piston mechanism 27 as the first mode switching means is set to the linkage mode, the contact surface 6C is separated from the base circle 10 and swings in conjunction with the main rocker arm 14 or the sub-rocker arm 15. It has become.

As shown in FIG. 2, the main rocker arm 14 is rotatably supported on the rocker shaft 16 and has a swing end 14A provided with a screw mounting portion 14B. . Then, the adjusting screw 21 that comes into contact with the stem end of the intake valve 2 is screwed to the mounting portion 14B. In addition, 21A is an adjustment nut.

As shown in FIGS. 1 and 2, an intermediate portion of the main rocker arm 14 is provided with a low speed roller 18 capable of contacting the low speed cam 12. This low speed roller 18
Is a shaft 1 pivotally supported in the middle of the main rocker arm 14.
It is pivotally supported by 8A via a roller bearing 18B so that it can smoothly rotate. This main rocker arm 1
The hydraulic piston mechanism 27 described above is provided between the rocker shaft 4 and the rocker shaft 16. This hydraulic piston mechanism 2
7 is a mode in which the main rocker arm 14 is rotatable with respect to the rocker shaft 16 and does not work in association with the rocker shaft 16 (that is, the main rocker arm 6) (uncoupling mode), and the main rocker arm 14 rotates integrally with the rocker shaft 16. Then, it can be set to any one of a mode (coordination mode) in which the main rocker arm 14 is linked to operate.

On the other hand, as shown in FIG. 2, the sub-rocker arm 15 is rotatably supported at its cylindrical base portion 15B so as to be rotatable with respect to the rocker shaft 16, and its swing end portion 15A is provided for high speed. A high speed roller 19 that can come into contact with the cam 13 is provided. As shown in FIGS. 1 to 3, the high-speed roller 19 also includes a roller bearing 19B on a shaft 19A that is rotatably supported by the swing end 15A of the sub-rocker arm 15.
It is pivoted so that it can rotate smoothly through.

Further, between the sub-rocker arm 15 and the rocker shaft 16, the above-mentioned hydraulic piston mechanism 17 is provided.
Is provided. The hydraulic piston mechanism 17 has a mode in which the sub-rocker arm 15 is rotatable with respect to the rocker shaft 16 and does not work in cooperation with the main rocker arm 14 (non-coupling mode), and the sub-rocker arm 15 rotates integrally with the rocker shaft 16 to perform main operation. Rocker arm 14
Can be set to any one of a mode (coordination mode) in which the link operation is performed.

Then, the hydraulic piston mechanism 1 of this embodiment
7, 27 have the same structure as each other as shown in FIGS. That is, the hydraulic piston mechanisms 17, 27 are
Piston chambers 17F, 2 formed in the rocker shaft 16
The pistons 17A and 27A are movably arranged in the diametrical direction of the rocker shaft 16 in 7F, and the pistons 17A and 27A are respectively placed in a position stored in the rocker shaft 16 and a position protruding from the rocker shaft 16. It has driving mechanisms 17J and 27J for driving them.

The drive mechanisms 17J and 27J are pistons 17
Springs 17B and 27B as biasing means for biasing A and 27A toward the storage position, and oil chambers 17G and 2 for hydraulically driving the pistons 17A and 27A toward the protruding position.
7G and means for supplying hydraulic pressure to the oil chambers 17G, 27G. That is, the other end of the piston 17A (the upper end in FIGS. 2 and 3, hereinafter, this end will be referred to as the tip) can enter the required position of the cylindrical base 15B of the sub-rocker arm 15. A recess 17C is formed, and the other end of the piston 27A (the upper end in FIG. 2, which is hereinafter referred to as the tip) is formed at a required position of the cylindrical base 14C of the main rocker arm 14. A recess 27C that can enter is formed. Note that 17E and 27E are lid members that form the recess 17C.

Collar-shaped portions 17H and 27H are formed on the outer circumferences of the base end portions of the pistons 17A and 27A, and step portions 17I and 27I are provided on the inner wall of the piston chamber.
Springs 17B and 27B are interposed in a compressed state between the collar-shaped portions 17H and 27H and the step portions 17I and 27I. Therefore, these pistons 17A, 27
A is urged to the storage position on the base end side by springs 17B and 27B.

Further, one end of the pistons 17A, 27A (the lower end in FIGS. 2 and 3, and this end is hereinafter referred to as the base end) and the sub-rocker arm 15 or the cylindrical base 15B of the main rocker arm 14. Oil chambers 17G and 27G are formed between the inner peripheral surface of 14C and the inner peripheral surface of 14C. Piston 17A,
Oil holes 17D and 27D are formed inside 27A to connect the oil passages 16A and 16B formed in the axial center portion of the rocker shaft 16 and the oil chambers 17G and 27G.

The oil chamber 17G is connected to the oil passage 16A of the rocker shaft 16 and the oil hole 17 of the piston 17A.
Hydraulic oil is introduced from D, and the oil passage 16B of the rocker shaft 16 and the oil hole 2 of the piston 27A are introduced into the oil chamber 27G.
The hydraulic oil is introduced from 7D. As a result, when the hydraulic oil is supplied to the oil chamber 17G, the piston 1 is resisted against the biasing force of the spring 17B as shown in FIG.
7A is driven toward the tip end side, and the tip end portion of the piston 17A comes to a protruding position where it is fitted into the recess 17C. On the other hand, oil chamber 1
When the supply of hydraulic oil to 7G is cut off, the piston 1 is urged by the urging force of the spring 17B as shown in FIGS.
7A is driven to the base end side, and the tip end portion of the piston 17A comes to the retracted position where it is removed from the recess 17C.

That is, in the hydraulic piston mechanism 17, when the hydraulic oil is supplied to the oil chamber 17G, the sub-rocker arm 15 is fitted into the recess 17C at the tip of the piston 17A.
Becomes a mode (coordination mode) in which it rotates integrally with the rocker shaft 16 and cooperates with the main rocker arm 6, and when the supply of hydraulic oil to the oil chamber 17G is cut off, the piston 17A is detached from the recess 17C at the tip, The sub-rocker arm 15 is set so as to be rotatable with respect to the rocker shaft 16 and not to operate in cooperation with the main rocker arm 6 (non-cooperation mode).

When hydraulic oil is supplied to the oil chamber 27G, as shown in FIGS. 10 and 11, the piston 27A is driven toward the tip end side against the biasing force of the spring 27B,
The tip of the piston 27A fits into the recess 27C. On the other hand, when the supply of hydraulic oil to the oil chamber 27G is cut off, as shown in FIG. 12, the piston 27A is driven toward the base end side by the urging force of the spring 27B, and the tip end portion of the piston 27A moves from the recess 27C. I'm supposed to take it off.

That is, in the hydraulic piston mechanism 27, when the hydraulic oil is supplied to the oil chamber 27G, the piston 27A is fitted into the recess 27C, so that the main rocker arm 1 is moved.
4 becomes a mode in which the main rocker arm 14 and the main rocker arm 6 cooperate with each other by rotating integrally with the rocker shaft 16 and the supply of hydraulic oil to the oil chamber 27G is cut off. The main rocker arm 14 is rotatable with respect to the rocker shaft 16 when the main rocker arm 1 is detached from the main rocker arm 1.
4 and the main rocker arm 6 are set so as to be in a mode in which the main rocker arm 6 and the main rocker arm 6 do not cooperate (non-cooperative mode).

The sub-rocker arm 15 is shown in FIGS.
As shown in FIG. 4, the main rocker arms 6 and 14 are arranged between the two main rocker arms 6 and 14, and the distance between the main rocker arms 6 and 14 is short. As a result, even when the main rocker arms 6 and 14 are driven at high speed via the sub-rocker arm 15, a slight twisting deformation is less likely to occur.

The hydraulic oil is supplied to the above-mentioned oil chambers 17G and 27G by the hydraulic oil supply system 5 as schematically shown in FIG.
It is supposed to be done through 1. The hydraulic oil supply system 51 includes a hydraulic pump (engine pump) 52 driven by an engine, and pressure adjusting means 53 for adjusting the hydraulic oil pressurized by the hydraulic pump 52 to a required hydraulic pressure.
The hydraulic oil whose pressure is adjusted by the pressure adjusting means 53 is supplied to the oil passage 16 described above.
It is provided with a switching valve 54 capable of switching between a supply state in which it is supplied to the oil chambers 17G and 27G through A and 16B and a supply stopped state in which it is not supplied.

The switching valve 54 is composed of, for example, a solenoid valve and has an electronic control unit (ECU) as a control means.
The switching valve 54 can be electronically controlled by 50. As a result, for example, as shown in FIG. 8, the switching point C corresponding to the engine speed, output torque, etc.
By setting 1 and C2, the modes of the hydraulic piston mechanisms 17 and 27 can be switched according to the engine speed and the output torque.

That is, in FIG. 8, both hydraulic piston mechanisms 17 and 27 are provided in a region where the engine speed and output torque are smaller than the switching point C1 (regions to the left and below the straight line of the switching point C1 in the figure). So that both are in the non-coordination mode.
No hydraulic pressure is supplied to 7. As a result, the one-valve low speed operation state (low speed stage) is realized.

In addition, the region where the engine speed and the output torque are between the switching point C1 and the switching point C2 (in the figure, the switching point C
1 and C2), the hydraulic piston mechanism 2
The switching valve 54 is set to a state in which hydraulic pressure is not supplied to the hydraulic piston mechanism 17 but hydraulic pressure is supplied to the hydraulic piston mechanism 27 so that the hydraulic piston mechanism 17 is in the cooperative mode and the hydraulic piston mechanism 17 is in the non-coordinated mode. As a result, a 2-valve low speed operation state (medium speed stage) is realized.

In a region where the engine speed and the output torque are larger than the switching point C2 (regions to the right and above the straight line of the switching point C2 in the figure), both hydraulic piston mechanisms 1 are provided.
The switching valve 54 is brought into a state of supplying hydraulic pressure to both hydraulic piston mechanisms 17 and 27 so that both 7 and 27 are in the linked mode. As a result, a 2-valve high-speed operating state (high-speed stage) is realized.

As shown in FIG. 3, a spring retainer 5A is provided on the upper end of the valve stem 3A of the intake valve 3, and a spring retainer 5B is provided on the cylinder head 1 side. 5
A valve spring 4 is interposed between B and B. As a result, the intake valve 3 is biased in the closing direction, that is, toward the upper end of the valve stem 3A. Therefore, the main rocker arm 6 also receives the base circle 1 through the valve spring 4.
The valve spring 4 is biased to the 0 side and acts as a restoring force when the main rocker arm 6 swings.

Although not shown, the intake valve 2 has the same structure as the intake valve 3, and the main rocker arm 14 is also urged toward the cam 12 through a valve spring (not shown) so that the urging force of the valve spring is increased. It acts as a restoring force when the main rocker arm 14 swings. On the other hand, the sub rocker arm 15
In the linkage mode, the main rocker arm 14 is integrated and receives the urging force of the valve spring 4, but in the non-coupling mode, the urging force is not received. Therefore, a means for urging the cam 13 side is provided, and the sub-rocker arm 15 is It is necessary to be able to follow the cam 13. Therefore, the sub-rocker arm 15 is provided with the lost motion mechanism 20.

As shown in FIG. 3, the lost motion mechanism 20 includes an outer case 20 fixed to a lost motion holder (not shown) installed on a cylinder head or the like.
A, an inner case 20B provided in the outer case 20A so as to be able to move back and forth and not to be separated from the outer case 20A, and a spring 20C interposed between the outer case 20A and the inner case 20B.
The contact portion 20D is formed at the end of the inner case 20B. The lever portion 15C provided on the sub-rocker arm 15 is in contact with the contact portion 20D, and the sub-rocker arm 15 is pressed toward the cam 13 side by the urging force of the spring 20C of the lost motion mechanism 20. A predetermined movement is performed according to the number 13.

By the way, the intake system 40 of this engine is
It is configured as shown in FIGS. That is, the throttle valve 43 is provided in the intake passage 42 on the downstream side of the air cleaner 41.
And a branched intake manifold 44 for each cylinder is provided downstream of the throttle valve 43. Further, each intake valve 2, is provided downstream of the intake manifold 44.
Intake ports 44A and 44B that are bifurcated toward 3
Are formed.

An injector (fuel injection means) 46 is installed on the upstream side of the intake ports 44A, 44B toward the opening of the intake ports 44A, 44B to the combustion chamber 45. The injector 46 is attached to the injector attachment portion 1C of the cylinder head with the direction of the fuel injection hole 46B set so that the fuel can be uniformly injected into the openings of the intake ports 44A and 44B.

An injector guide 49 as fuel injection guide means is provided outside the tip portion 46A of the injector 46. This injector guide 49
As shown in FIGS. 6A, 6B, and 6C, is the tip portion 46A of the injector 46 and the injector mounting portion 1C.
Is interposed between the pipe portion 49A and the base portion 49
C and the pipe portion 49A and the base portion 49C
An air flow path 49B and an air injection port 49D are formed inside the. Then, by injecting air from the air injection port 49D, the fuel injected from the injection hole 46B is deflected to one intake valve 2 side. Therefore,
The directions of the air passage 49B and the air injection port 49D are set in the direction of the intake valve 2.

In this embodiment, as shown in FIG. 6 (C), the air injection port 49D is formed by three holes, but the air injection port is not limited to this. As shown in FIG. 7, an air injection port with an arcuate slit 49E can be considered. However, in FIG. 7, the description of the pipe portion 49A is omitted. Further, in this embodiment, an idle speed adjusting means (idle speed controller; hereinafter abbreviated as ISC) is also used as a means for supplying air to the injector guide 49.
The ISC 47 has an intake bypass passage 48A and an opening / closing valve 47A that opens and closes the intake bypass passage 48A. The intake bypass passage 48A is formed from a portion of the intake passage 42 upstream of the throttle valve 43 to each intake manifold 44, and the opening / closing valve 4 is provided at the upstream opening 48B.
7A is provided. And the intake bypass passage 48A
The downstream opening 48C is directed toward the injector guide 49, and the air passing through the intake bypass passage 48A is ejected from the injector guide 49.

The on-off valve 47A also serves as fuel injection guide switching means for switching the operating state of the injector guide 49, that is, the state of injecting air from the air injection port 49D of the injector guide 49 and the state of not injecting air. That is, the opening / closing valve 47A is opened when the intake valve 3 is closed so that the air is injected from the injector guide 49, and is closed when the intake valve 3 is activated to stop the air injection from the injector guide 49. Operate.

The on-off valve 47A is a solenoid 47B.
The solenoid valve is driven by the ECU 50 and its operation is controlled by the ECU 50. That is, the ECU 50
Controls the opening degree of the on-off valve 47A so that a predetermined idle speed state is achieved when the engine is idle, and the on-off valve 47A is opened when the intake valve 3 is closed (at the time of one valve low speed operation).
Control is performed so that A is opened and air is injected from the intake bypass passage 48A and the injector guide 49.

Further, at the time of operation for one valve low speed, the intake air forms a swirl in the combustion chamber 45 to distribute the air-fuel mixture in a layered manner, so that the fuel-rich air-fuel mixture is unevenly distributed in the vicinity of the spark plug as a whole. Is being used to produce lean fuel with less fuel. Therefore, when this one-valve operation is performed, a correspondingly small amount of fuel is injected from the injector 46.

Although not shown, in this engine,
Like the intake valve, the exhaust valve is also provided as a two-valve pair, and these two exhaust valves are also opened and closed in the low speed mode by the low speed cam at the low speed and at the high speed at the high speed as shown in FIG. It is designed to open and close in high-speed mode by the cam. Since the engine with the variable valve timing mechanism according to the first embodiment of the present invention is configured as described above, the intake valves or the exhaust valves 2 and 3 operate as follows according to the engine speed and the output torque. To do.

That is, as shown in FIG. 8, in the low speed rotation region where the engine speed and the output torque are smaller than the switching point C1, the switching valve 54 causes the hydraulic piston mechanisms 17, 2 to operate.
The hydraulic pressure is not supplied to 7. As a result,
As shown in FIG. 2, the pistons 17A and 27A are urged toward the base end side by springs 17B and 27B, respectively, and the pistons 17A and 27A are held in a state in which their tip ends are removed from the recesses 17C and 27C. To be done.

Therefore, the sub-rocker arm 15 and the main rocker arm 14 are both freely rotatable with respect to the rocker shaft 16 and are in the non-coupling mode in which the sub-rocker arm 16 and the main rocker arm 6 do not work together. As a result, the main rocker arm 14
Is opened / closed according to the low speed cam 12, while the main rocker arm 6 is held in a closed state while contacting the base circle 10, and only the main rocker arm 14 is opened / closed at a low speed valve timing. Low speed stage) is realized.

At this time, the opening / closing valve 47A is opened, and the intake bypass passage 48A and the injector guide 4 are opened.
Air is ejected from the air ejection port 49D of No. 9. And
By the air that is injected against, the fuel injected from the injection hole 46B is deflected to the side of the intake valve 2 that opens and closes.
As a result, fuel is not injected to the side of the intake valve 3 that is at rest, combustion fluctuation due to fuel accumulation on the side of the pause valve is prevented, normal combustion is secured, and deterioration of exhaust gas is also prevented. There is an advantage.

Particularly, in this embodiment, since the fuel injection direction is deflected by utilizing the ISC 47, there is an advantage that such fuel accumulation can be prevented at low cost. In this one-valve low-speed operating state, the intake air can form a strong swirl in the combustion chamber 45, and the intake air can be stratified to partially unevenly distribute the rich fuel mixture in the vicinity of the spark plug. it can. As a result, lean combustion can be realized while stabilizing the combustion without lowering the combustion speed and deteriorating the ignitability, and it is possible to significantly improve the fuel efficiency of the engine and reduce harmful exhaust gas.

As a result, in the one-valve low speed operation state, the output torque of the engine peaked in the low speed rotation range of the engine can be obtained with a small fuel consumption, as shown by the curve a.
Further, in general, when the hydraulic pump 52 is driven by an engine, no hydraulic output is generated at the time of starting. However, in this embodiment, the low speed stage is set to each hydraulic piston mechanism 1
Since this is realized without supplying hydraulic pressure to 7 and 27, the engine can be started in the low speed stage of the one valve low speed operation without requiring hydraulic pressure.

Therefore, when starting the engine, only one valve needs to be operated, and the cranking force of the starter is sufficient to correspond to the valve spring force of only one valve. As a result, there is an advantage that the starter can be downsized.
Further, as shown in FIG. 8, in the medium speed rotation region in which the engine speed and the output torque are larger than the switching point C1 and smaller than the switching point C2, the hydraulic piston mechanism 1 is operated by the switching valve 54.
The hydraulic pressure is not supplied to 7, but the hydraulic piston mechanism 27 is supplied with the hydraulic pressure.

As a result, as shown in FIG. 11, the piston 17A is urged by the spring 17B toward the base end side thereof, and the tip end thereof is held in a state of being released from the recess 17C. On the other hand, due to the hydraulic pressure supplied to the oil chamber 27G, the piston 27A is driven toward the tip end side against the biasing force of the spring 27B, and the tip end portion is fitted into the recess 27C.

Therefore, the main rocker arm 14 is rotated integrally with the rocker shaft 16 to enter the link mode in which the main rocker arm 6 is linked to the main rocker arm 6, and the sub rocker arm 15 is rotatable with respect to the rocker shaft 16 and linked to the main rocker arm 6. Not in non-coordination mode. As a result, the main rocker arms 14 and 6 both open and close according to the low speed cam 12, and the main rocker arm 1
A 2-valve low speed operating state (medium speed stage) in which 4 and 6 are opened and closed at low speed valve timing is realized.

In this two-valve low-speed operating state, the output torque of the engine has a peak in the medium-speed rotation range of the engine, as shown by the curve b. Further, as shown in FIG. 8, in the high speed rotation region where the engine speed and the output torque are larger than the switching point C2, the switching valve 54 causes the hydraulic piston mechanism 17 to operate.
Also, the hydraulic pressure is supplied to the hydraulic piston mechanism 27.

As a result, as shown in FIG. 10, the pistons 27A and 27A are driven toward the tip end side against the urging force of the springs 17B and 27B by the hydraulic pressure in the oil chambers 17G and 27G. The tip is a recess 17C,
Insert into 27C. Therefore, the main rocker arm 1
4 and the sub-rocker arm 15 rotate integrally with the rocker shaft 16 to enter a linkage mode in which the sub-rocker arm 16 and the main rocker arm 6 are linked.

Since the cam profile of the high speed cam 13 is large so as to include the cam profile of the low speed cam 12, both the main rocker arms 14 and 6 are opened and closed according to the high speed cam 13 so that the main rocker arms 14 and 6 are used for high speed. A 2-valve high-speed operating state (high-speed stage) that opens and closes at valve timing is realized. In the two-valve high-speed operating state, the output torque of the engine peaks in the high-speed rotation range of the engine, as indicated by the curve c.

Thus, while switching the intake valves 2 and 3 between the low speed stage, the medium speed stage and the high speed stage, efficient combustion can be realized in a wide rotation range of the engine, especially at low speed rotation. It is possible to achieve significant fuel economy savings due to lean combustion, and to obtain sufficient output in the mid-high speed rotation range. In particular, when the engine rotates at medium speed, both intake valves 2 and 3 open and close with the low-speed opening / closing characteristic, so that control including the timing of fuel supply can be appropriately performed, and combustion stability can be secured.

Further, when the low speed stage and the medium speed stage are switched, one of the intake valves is switched from the rest to the low speed opening / closing, so that the change of the intake can be made gradually near this switching point, and the smooth engine output characteristic can be obtained. Easy to get. Further, in this embodiment, since the hydraulic piston mechanisms 17 and 27 are similarly configured, there is an advantage that the manufacturing cost can be reduced by sharing the parts.

Further, since the sub-rocker arm 15 is arranged between the two main rocker arms 6 and 14, the accuracy is high when the both main rocker arms 6 and 14 are driven at high speed through the sub-rocker arm 15 in the high speed stage. There is also an advantage that the valve is driven well and properly. Next, a second embodiment will be described. In this embodiment, the hydraulic piston mechanism 3 on the main rocker arm 14 side is used.
7 is different from that of the first embodiment.

That is, as shown in FIG. 13, the hydraulic piston mechanism 37 includes a piston 37A movably arranged in the diameter direction of the rocker shaft 16 in a piston chamber 37F formed in the rocker shaft 16. One end of the piston 37A (upper side end portion in FIGS. 2 and 3;
This end is referred to as a tip, and the other end is referred to as a base). .

Further, inside the piston 37A, an oil hole 37D is formed which connects the oil passage 16B formed in the axial center portion of the rocker shaft 16 and the oil chamber 37C. Further, a spring 37B is interposed in a compressed state at the base end of the piston 37A. Incidentally, 37E is a spring retainer. As a result, when the hydraulic oil is supplied to the oil chamber (recess) 37C, the piston 37A is driven to the rear end side against the biasing force of the spring 37B, as shown in FIG. The tip portion is adapted to come out of the recess 37C. On the other hand, when the hydraulic oil supply to the oil chamber 37G is cut off, the piston 37A is driven toward the tip end side by the biasing force of the spring 37B, and the tip end portion of the piston 37A is recessed 37C as shown in FIGS. It is designed to fit in.

That is, in the hydraulic piston mechanism 37, when the hydraulic oil is supplied to the oil chamber (recess) 37C, the piston 37
By detaching the tip end of A from the recess 37C, the main rocker arm 14 is rotatable with respect to the rocker shaft 16, and the main rocker arm 14 and the main rocker arm 6
When and are in a mode in which they do not work together (non-coupling mode), and the supply of hydraulic oil to the oil chamber (recess) 37C is cut off, the main rocker arm 14 is inserted into the recess 37C at the tip of the piston 37A, causing the rocker shaft 14 to move. It is set so that the main rocker arm 14 and the main rocker arm 6 rotate in unison with each other 16 to operate in a coordinated manner (cooperative mode).

The engine having a variable valve timing mechanism according to the second embodiment of the present invention constructed as described above operates in substantially the same manner as that of the first embodiment, except for the hydraulic control of the hydraulic piston mechanism 37. However, almost the same action and effect can be obtained. In each of the above embodiments, the first rocker arm (main rocker arm) 6 is formed integrally with the rocker shaft 16.
It suffices that the rocker arm 6 can rotate around the rocker shaft 16, and when the rocker arm 6 is configured separately from the rocker shaft 16, the rocker arm 6 and the rocker arms 14 and 15 are provided with mode switching means 17 and 27, respectively.
Should be installed.

[0118]

As described above in detail, the engine with a variable valve timing mechanism according to the present invention according to claim 1 is
Low-speed cam that rotates in response to the rotation of the crankshaft of the engine, and a low-speed cam that has two intake valves, the second intake valve and the second intake valve, and a cam profile for low-speed valve timing. A cam for high speed which includes a cam profile for high speed valve timing including a cam profile for high speed and which rotates in response to rotation of the crankshaft, a rocker shaft pivotally supported at a required portion of the engine, and a low speed Is provided so as to rotate around the rocker shaft but does not directly contact the operation cam and the high speed cam, and contacts the first intake valve to open and close the first intake valve. A rocker arm and a low speed roller capable of contacting the low speed cam are provided so that the rocker arm can swing corresponding to the cam profile of the low speed cam and contact the second intake valve. A second rocker arm that drives the second intake valve to open and close; a third rocker arm that includes a high-speed roller that abuts against the high-speed cam and that swings corresponding to the cam profile of the high-speed cam; First mode switching means for switching between a non-coupling mode in which the rocker arm is not linked to the first rocker arm and a linking mode in which the rocker arm is linked to the first rocker arm; Second mode switching means capable of switching between the cooperation mode and the cooperation mode for coordinating, and control means for controlling the states of the first mode switching means and the second mode switching means in accordance with the rotation state of the engine. With such a configuration, the intake valve can be switched between three stages, for example, a low speed stage, a medium speed stage, and a high speed stage, and a wide engine can be used. In the rolling region, can achieve efficient combustion, can savings in fuel consumption during low-speed rotation, it is possible to obtain a sufficient output in the mid-high speed range.

In particular, since both intake valves can be opened / closed at low speed opening / closing characteristics, for example, when the engine rotates at medium speed, control including the timing of fuel supply can be appropriately performed to ensure combustion stability. it can. Furthermore, since one of the intake valves can be switched from the rest state to the low speed opening / closing state, the intake air can be changed gently near this switching point, and a smooth engine output characteristic can be easily obtained.

According to the engine with variable valve timing mechanism of the present invention, the second rocker arm and the third rocker arm are both rotatably attached to the rocker shaft. The first mode switching means is formed on the rocker shaft, has a first piston chamber having an opening exposed on the outer peripheral surface of the rocker shaft, and the second rocker arm is formed on the side of the second rocker arm. And a first recess that aligns with the opening of the first piston chamber when the relative phase between the rocker shaft and the rocker shaft is in a predetermined state, and a direction that is orthogonal to the axis of the rocker shaft in the first piston chamber. And a protruding position in which one end of the rocker shaft is inserted into the first recess and is inserted into the first recess and the one end of the rocker shaft is protruded from the outer peripheral surface of the rocker shaft. And a second drive mechanism for driving the first piston between the projecting position and the retracted position. Second mode changing means is formed in the rocker shaft and has an opening exposed on the outer peripheral surface of the rocker shaft, and the third rocker arm and the rocker shaft are formed on the side of the third rocker arm. And a second recess that is aligned with the opening of the second piston chamber when the relative phase between the second piston chamber and the second piston chamber is in a predetermined state, and the second recess can move in a direction orthogonal to the axis of the rocker shaft. And a storage position in which one end of the rocker shaft is protruded from the outer peripheral surface of the rocker shaft and is fitted into the second recess and a storage position of which the one end is not projected from the outer peripheral surface of the rocker shaft. 2 fixers When, by being configured to include a second drive mechanism for driving between the second piston projecting position and the retracted position, the above-mentioned 3
It is possible to reliably switch between the two stages and to achieve efficient combustion in a wide rotation range.

According to the engine with variable valve timing mechanism of the present invention as defined in claim 3, the first drive mechanism urges the first piston toward the storage position side or the protruding position side. First urging means, a first oil chamber formed to drive the first piston against the first urging means toward the protruding position side or the storage position side, and the engine Is configured to include a first hydraulic pressure supply means capable of supplying a required hydraulic pressure into the first oil chamber when the rotational speed is a required rotation state, and the second drive mechanism includes the second piston. A second urging means for urging the second piston toward the storage position side or the protruding position side, and drive the second piston against the second urging means toward the protruding position side or the stored position side. The second formed to
Oil chamber and the second when the engine is in the required rotation state.
And a second hydraulic pressure supply means capable of supplying a required hydraulic pressure into the oil chamber, so that the hydraulic pressure can be supplied while using, for example, an engine-driven hydraulic pump, and the variable valve described above is used. The timing mechanism can be easily realized.

According to another aspect of the engine with variable valve timing mechanism of the present invention, the first urging means and the second urging means include the first piston and the second piston. All the pistons are urged toward the retracted position,
Is set so as to supply a required hydraulic pressure into the first oil chamber when the engine is in a medium speed or high speed rotation state, and the second hydraulic pressure supplying means controls With the configuration in which the required oil pressure is supplied to the second oil chamber in the high speed rotation state, for example, when the oil pressure is supplied by using the engine-driven hydraulic pump, when the engine is started, It is possible to realize a mode in which only one intake valve is operated. As a result, the cranking force of the starter is sufficient to correspond to the valve spring force of only one valve, and there is an advantage that the starter can be downsized. Further, there is an advantage that the manufacturing cost can be reduced by sharing the two parts of the hydraulic piston mechanism.

According to the engine with variable valve timing mechanism of the present invention as defined in claim 5, an engine pump in which both the first hydraulic pressure supply means and the second hydraulic pressure supply means are driven by the engine. The variable valve timing mechanism can be easily realized by the configuration in which the hydraulic pressure source is used. According to another aspect of the engine with variable valve timing mechanism of the present invention, the control means determines whether the rotational speed range of the engine is in a low speed range, a medium speed range, or a high speed range. Then, when the engine is set to control the states of the first mode switching means and the second mode switching means and the engine is in the low rotation speed range, the first mode switching means and the second mode switching means are set. The second rocker arm is set to a non-coupling mode in which the second rocker arm is not linked to the first rocker arm and the third rocker arm is set to a non-coupling mode in which the first and second rocker arms are not linked to each other through the mode switching means. When the engine is in the medium speed range, the first intake valve is closed and the second intake valve is opened and closed in response to the cam profile of the low speed cam. To Through the first mode switching means and the second mode switching means,
By setting the second rocker arm in a linkage mode in which the first rocker arm and the first rocker arm are linked to each other, and setting the third rocker arm in a non-linkage mode in which the third rocker arm is not linked to the first and second rocker arms, Intake valve and the second
Both of the intake valves are opened and closed in correspondence with the cam profile of the low speed cam to operate at a low speed of two valves, and when the engine is in a high rotational speed range, the first mode switching means and the second mode switching The second rocker arm is linked to the first rocker arm by a means, and the third rocker arm is linked to the first and second rocker arms. With a configuration in which both the first intake valve and the second intake valve are set to be in a two-valve high speed operation state in which they are opened and closed in accordance with the cam profile of the high speed cam,
Achieves efficient combustion in a wide engine rotation range,
In particular, when the engine runs at low speeds, it is possible to realize a significant saving in fuel consumption due to lean combustion, and it is possible to obtain sufficient output in the mid-high speed rotation range.

Further, according to the engine with a variable valve timing mechanism of the present invention as defined in claim 7, both of the first intake valve and the second intake valve are provided in the downstream portion of the intake passage of the engine. Fuel injection means for injecting fuel toward the second intake valve is provided, and fuel injection guide means for deflecting the fuel injected from the injection hole of the fuel injection means toward the second intake valve is provided. The fuel injection guide switching means is provided to operate the fuel injection guide means when the valve is opened and to stop the fuel injection guide means when the first intake valve is operated. Has the advantages that fuel is not injected, combustion fluctuations due to fuel accumulation on the pause valve side are prevented, normal combustion is secured, and deterioration of exhaust gas is prevented.

According to the engine with variable valve timing mechanism of the present invention as defined in claim 8, in the intake passage,
Downstream of the intake bypass passage is provided with an idle rotation speed adjusting means provided with an intake bypass passage provided from an upstream portion to a downstream portion of the intake passage and an opening / closing valve for opening and closing the intake bypass passage. An end portion is connected to the fuel injection guide means, and the fuel injection guide means injects the intake air guided by the intake bypass passage in a required direction to thereby inject fuel injected from the injection hole into the second intake valve. With the configuration in which the fuel injection guide switching unit is configured to be deflected to the side and the on-off valve is used as the fuel injection guide switching unit, there is an advantage that the fuel pool can be prevented at low cost.

According to the ninth aspect of the engine with variable valve timing mechanism of the present invention, the third rocker arm is interposed between the first rocker arm and the second rocker arm. According to the configuration, there is an advantage that the valve can be driven accurately and appropriately.

[Brief description of drawings]

FIG. 1 is a perspective view of a valve train of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 2 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 3 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 5 is a sectional view of an essential part of an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 6 is a view showing an air injection port member provided in an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention, where (A) is (B) and FIG.
3 is a view as viewed from an arrow A in FIG.

FIG. 7 is a view showing a modified example of the air injection member of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 8 is a diagram showing output characteristics of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 9 is a diagram showing a valve lift state of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 10 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 11 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 12 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 13 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a second embodiment of the present invention.

FIG. 14 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 15 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 16 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 17 is a diagram showing a cam profile of a conventional engine with a variable valve timing mechanism.

FIG. 18 is a diagram showing output characteristics of a conventional engine with a variable valve timing mechanism.

FIG. 19 is a cross-sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

FIG. 20 is a side view showing a cam of a valve train of an engine with a variable valve timing mechanism of another conventional example.

FIG. 21 is a diagram showing output characteristics and hydraulic control characteristics of a valve operating system of a conventional engine with a variable valve timing mechanism.

FIG. 22 is a cross-sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

FIG. 23 is a sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

[Explanation of symbols]

 1A Bearing part 1C Injector mounting part 2 Second intake valve 3 First intake valve 3A Valve stem 4 Valve spring 5A, 5B Spring retainer 6 First rocker arm (main rocker arm) 6A Swing end 6B Screw mounting part 6C Contact surface 10 Base circular cam (base circle) 11 Cam shaft 12 Low speed cam 13 High speed cam 14 Second rocker arm (main rocker arm) 14A Swing end portion 14B Screw mounting portion 14C Cylindrical base portion 15 Third rocker arm ( Sub rocker arm) 15A Oscillating end portion 15B Cylindrical base portion 15C Lever portion 16 Rocker shaft 16A, 16B Oil passage 17 Hydraulic piston mechanism as second mode switching means 17A Piston 17B Spring 17C Recess 17D Oil hole 17E Lid member 17F Piston Room 17 G Oil chamber 17H Collar portion 17I Step portion 18 Low speed roller 18A Shaft 18B Roller bearing 19 High speed roller 19A Shaft 19B Roller bearing 20 Lost motion mechanism 20A Outer case 20B Inner case 20C Spring 20D Contact portion 21, 22 Adjust screw 21A , 22A adjusting nut 27 hydraulic piston mechanism as a first mode switching means 27A piston 27B spring 27C recess 27D oil hole 27E lid member 27F piston chamber 27G oil chamber 27H collar-shaped portion 27I step portion 37 hydraulic piston mechanism 37A piston 37B spring 37C Recess 37D Oil Hole 37E Spring Retainer 37F Piston Chamber 37G Oil Chamber 40 Intake System 41 Air Cleaner 42 Intake Passage 43 Throttle Valve 44 Intake Manifold 4 A, 44B Intake port 45 Combustion chamber 46 Injector (fuel injection means) 46A Injector tip portion 46B Fuel injection hole 47 Idle rotation speed adjusting means (ISC) 47A Open / close valve as fuel injection guide switching means 47B Solenoid 48A Intake bypass passage 48B Upstream Side opening 48C Downstream opening 49 Injector guide as fuel injection guide means 49A Pipe part 49C Base part 49B Air flow path 49D Air injection port 49E Arc-shaped slit as air injection port 50 Electronic control unit as control means ( ECU) 51 hydraulic oil supply system 52 hydraulic pump (engine pump) 53 pressure adjusting means 54 switching valve

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[Procedure amendment]

[Submission date] May 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of the invention Engine with variable valve timing mechanism

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine having a valve operating system that opens and closes an intake valve in response to the rotation of a crankshaft, and more particularly to an engine having two intake valves depending on the rotational speed state of the engine. The present invention relates to an engine with a variable valve timing mechanism capable of switching the operating states of these two intake valves.

[0002]

2. Description of the Related Art In recent years, the improvement of the fuel consumption rate (fuel consumption) of an engine such as an automobile is not only from the viewpoint of effective use of energy resources, but also from the viewpoint of protecting the global environment by reducing harmful exhaust gas from the engine. It is also strongly requested by However, on the other hand, for example, an engine for an automobile is required to have a certain acceleration performance and a high-speed performance as well as a sufficient output characteristic as a practical vehicle from a low-speed rotation range to a low-speed rotation range to a high-speed rotation range. ing.

By the way, in order to promote the improvement of fuel consumption, it is necessary to secure a sufficient torque in the low speed rotation range so as to be sufficiently practical in the low speed rotation range. On the other hand, in order to secure sufficient acceleration performance and high speed performance, it is necessary to secure sufficient torque in the high speed rotation range. However, generally, there is a conflict between securing torque in the low speed rotation range and securing torque in the high speed rotation range, and it has been difficult to realize both at the same time.

Therefore, in an OHC (overhead camshaft) type engine used in automobiles, etc., a valve operating system for opening and closing intake valves and exhaust valves is operated to open / close timing of these intake / exhaust valves and a lift amount at opening. A device has been developed in which the torque in the low-speed rotation range and the torque in the high-speed rotation range can be sufficiently secured by changing the torque in accordance with the rotation state of the engine.

In such a device (that is, a variable valve timing mechanism), for example, a camshaft is equipped with a high speed cam and a low speed cam, and either the high speed cam or the low speed cam is provided. By selecting and using it, the opening / closing timing of the intake / exhaust valve corresponding to the operating state can be obtained. The low speed cam is, for example, as shown in FIG.
As shown by the curve 3a ', a cam profile capable of obtaining the opening / closing timing corresponding to the low speed operation is provided, and the high speed cam is designed for high speed operation as shown by the curve 3b' in FIG. It has a cam profile that can get the corresponding opening and closing timing. That is, the high-speed cam has a longer valve opening time and a larger valve lift amount than the low-speed cam.

As a mechanism for selecting the high-speed cam and the low-speed cam, in the rocker arm type cam device, the valves are driven by the high-speed cam by connecting or disconnecting the rocker arms to each other. Alternatively, the valve is driven by a low speed cam to obtain the opening / closing timing of the intake / exhaust valve corresponding to the operating state.

As a result, the low speed cam provides a torque characteristic as shown by a curve 3a 'in FIG. 18, and the high speed cam gives a torque characteristic as shown by a curve 3b' in FIG. Is obtained. Then, with the engine speed Ne _{0 at} which these characteristic curves intersect as a switching point, a low speed cam is selected in a lower speed rotation range than this, and a high speed cam is selected in a higher speed rotation range than this, thereby making a wide range. Torque characteristics with high torque and little fluctuation can be obtained in the engine speed range.

However, in the variable valve timing mechanism as described above, only two stages, a low speed stage as indicated by reference numeral 3a 'and a high speed stage as indicated by reference numeral 3b', can be switched, so that a sufficiently wide engine rotation is possible. There is a limit to obtaining a flat torque characteristic with high torque and small fluctuation in several ranges. In other words, with only two stages, low speed and high speed, in order to obtain high torque in a wide engine speed range, the maximum torque of the low speed stage is shifted to the side where the engine speed is lower, and the maximum torque of the high speed stage is increased. It is conceivable that the engine speed is shifted to a higher engine speed side. However, in this case, the torque tends to decrease in the region near the engine switching point rotation speed Ne ₀ , and it becomes difficult to obtain a flat torque characteristic.

Therefore, there has been proposed a device which can be switched to three stages of a low speed stage, a medium speed stage and a high speed stage. For example, FIGS. 19 to 22 show a variable valve timing mechanism disclosed in Japanese Patent Laid-Open No. 3-229906. As shown in FIGS. 19 to 22, a low speed cam 3a 'having a cam profile for low speed operation and a high speed cam 3b' as a driving member having a cam profile for high speed operation are arranged in parallel. ing. The characteristics of the cam profiles for low speed operation and high speed operation are set in the same manner as those shown by curves 3a 'and 3b' in FIG. 17, for example.

On the other hand, the low speed cam 3 is attached to the rocker shaft (arm shaft) 9'which is arranged in parallel with the cam shaft.
A primary rocker arm 4'driven by a'and a secondary rocker arm 13'driven by a high speed cam 3b 'are arranged in parallel. Primary rocker arm 4 '
Is rotatably attached to the arm shaft 9 ', but is also rotatable integrally with the arm shaft 9'by a lock mechanism R'.

The arm portion of the primary rocker arm 4'is provided with a shaft 6'on which a roller bearing (roller with bearing) 5'is mounted. The upper part of the roller bearing 5'is a low speed cam 3a '.
Is engaged with. That is, the primary rocker arm 4 '
Receives the driving force from the low speed cam 3a 'via the roller bearing 5'and the shaft 6'.

An adjusting screw 7 ', which is appropriately adjusted in position and fixed by a nut 8', is attached to the tip of the primary rocker arm 4 '. The valve stem upper end 1a 'of the valve 1'is engaged.
The valve stem upper end 1a 'is urged obliquely upward to the right in FIG. 22 by the valve spring 2'.

Therefore, the tip of the primary rocker arm 4'is swung in the vertical direction in FIG. 22 by the rotation of the low speed cam 3a ', and the valve 1'is driven vertically by the adjusting screw 7'. . On the other hand, in the arm part of the secondary rocker arm 13 ',
A shaft 14 'equipped with a roller bearing (roller with bearing) 15' is provided, and the upper portion of the roller bearing 15 'is engaged with the high speed cam 3b'. That is, the secondary rocker arm 13 'receives a driving force from the high speed cam 3b' via the roller bearing 15 'and the shaft 14'.

The secondary rocker arm 13 'is also pivotally supported by the rocker shaft 9', but the secondary rocker arm 13 'is always rotated integrally with the rocker shaft 9'by a half-moon key 12' interposed therebetween. It is fixed to. In addition, the secondary rocker arm 13 '
The lower end surface (that is, the lower surface of the roller bearing 15) on the swinging end side of the support spring (lost motion spring) 16
Cylinder head 17 'through piston 16' with a '
The urging force of the support spring 16a 'acts as a restoring force when the secondary rocker arm 13' swings.

Therefore, when the high speed cam 3b 'rotates, the rocker shaft 9'will always rotate repeatedly at the same time when the secondary rocker arm 13' swings.
By the way, the above-mentioned lock mechanism R'is configured as follows. That is, as shown in FIG. 19, a pin hole 9b 'extending in the radial direction of the shaft 9'is formed in the pivotal support portion of the primary rocker arm 4'of the rocker shaft 9', and this pin hole 9b 'is formed. The lock pin 10 'is loosely inserted.

The lock pin 10 'can be projected outward from the rocker shaft 9'by a pin drive mechanism P, and the lock pin 10' is provided on the inner circumference of a pivotal support portion of the rocker arm 4'to the rocker shaft 9 '. Is formed with a pin lock hole 4a 'into which the lock pin 10' can be fitted. By the way, the pin drive mechanism P of the lock pin 10 'is configured as follows. That is, a hydraulic passage 9a 'extending along the axis of the rocker shaft 9'is provided in the central portion of the rocker shaft 9', and an oil groove 10a 'is formed in the outer periphery of the central portion of the lock pin 10' to form an oil groove 10a '. From the outer peripheral surface of the lock pin 10 'to the axial center portion, and the hydraulic pressure of the hydraulic passage 9a' is controlled by the oil groove 10a 'and the hydraulic pressure supply hole. 10b '
It is adapted to be supplied to the rear end side of the lock pin 10 'via the.

A large diameter portion 10c 'is formed on the outer periphery of the rear end portion of the lock pin 10', and the large diameter portion 1 is formed in the pin hole 9b '.
A large diameter hole for sliding 0c 'and a small diameter hole for sliding the upper part of the lock pin 10' are formed. And the pin hole 9
Step b'from the small diameter hole to the large diameter hole of b'and the lock pin 1
A spring 1 is provided between the stepped portion of the large diameter portion 10c 'of 0'.
1'is interposed to urge the lock pin 10 'toward the rear end side.

As a result, when the hydraulic pressure is not supplied from the hydraulic passage 9a ', the lock pin 10' is driven to the rear end side, and the curved end face at the rear end is the inner circumference of the rocker shaft insertion hole 4b 'of the primary rocker arm 4'. When the lock pin 10 'is engaged with the surface or comes very close to it, the tip of the lock pin 10' is retracted inward from the outer peripheral surface of the rocker shaft 9 ', and the primary rocker arm 4'is fixed to the rocker shaft 9'. It will not be done.

On the other hand, when the hydraulic pressure is supplied from the hydraulic passage 9a ', the hydraulic pressure is supplied to the rear end side of the lock pin 10', and the large diameter portion 10c 'of the lock pin 10' is connected to the front end side and the rear end side. Lock pin 1 due to the differential pressure due to the difference in pressure receiving area
The driving force of 0'acts, and this driving force acts on the spring 11 '.
The lock pin 10 'enters into the pin lock hole 4a' of the primary rocker arm 4 '.

As a result, the lock pin 10 'and the pin lock hole 4a' are fitted, the primary rocker arm 4'and the rocker shaft 9'are fixed, and the primary rocker arm 4'is rocked integrally with the rocker shaft 9 '. Move. The rocker shaft 9'of the primary rocker arm 4 '
The axial position of is held by the snap ring 19 'and the thrust spring 18'.

In such a mechanism, for example, the curve shown in FIG.
As indicated by d, output pressure increases with engine speed
Use an engine pump that
While giving the changing hydraulic pressure to the above valve operating system,
Can be activated. That is, engine rotation
The first number of switching revolutions N₁Both intakes in the following range a
Both valves open and close for low speed. The engine speed is the first cut
Replacement speed N₁If it exceeds, the second switching speed N₂Since
In the lower range b, one intake valve opens and closes for high speed and the other intake valve opens.
The air valve opens and closes for low speed. Furthermore, the engine speed is the second
Switching speed N ₂In the above range c, both intake valves
Open and close for high speed.

As a result, the torque characteristics of the three stages of the low-speed stage, the medium-speed stage, and the high-speed stage in the respective rotational speed regions are shown by t ₁ , t ₂ , and t ₃ , and in the wide rotational speed region of the engine. Large torque, smooth and flat torque characteristics can be obtained. By the way, as described above, by switching the opening / closing timing of the intake valve, the opening time and the valve lift amount by the low speed cam and the high speed cam, while securing the acceleration performance and the high speed performance while using the low speed rotation range of the engine. Although low fuel consumption can be realized, such a method has a limit in improving fuel consumption and reducing harmful exhaust gas.

Therefore, a lean burn engine has been proposed in recent years as a means for reducing harmful exhaust gas while significantly improving the fuel efficiency of the engine. In such a lean-burn engine, the air-fuel ratio A / F of the air-fuel mixture is increased so that sufficient combustion energy can be obtained with a small amount of fuel.
However, if such leaning of the air-fuel mixture is promoted, the combustion speed is lowered and the ignitability is deteriorated when the temperature exceeds a certain condition, resulting in unstable combustion.

By the way, in order to realize the rapid combustion of the engine, it is necessary to promote the mixing of the fuel and the air and to increase the speed of flame propagation after ignition. As a most effective means for this purpose, it is considered that swirl (vortex flow) is generated to increase the flow velocity of the air-fuel mixture in the cylinder. However, in order to generate a strong swirl, there is no choice but to reduce the cross-sectional area of the suction port, and as a result, suction resistance increases and the output of the engine decreases. Also, in a four-valve engine with two intake valves and two exhaust valves,
It is difficult to generate swirl while maintaining engine output. Conversely, if intake air is made to flow from one intake port that is eccentric to the cylinder axis,
Easy to generate swirl.

Therefore, in a valve operating system with a variable valve timing mechanism having two stages, a low speed stage and a high speed stage, one of the two intake valves is stopped as a low speed stage and only one valve is used for intake. Have been developed. In other words, the camshaft is
7 has a cam (valve drive cam) having a characteristic for driving the intake valve with a characteristic shown by 3a 'or 3b and a cam (valve rest cam) close to the base circle, and one of the two intake valves is The switching mechanism can switch between a state in which the valve drive cam is driven and a state in which the valve stop cam is stopped. The other of the two intake valves has no switching mechanism and is always driven by the valve drive cam.

With such a structure, in the high speed stage, both intake valves are driven by the valve drive cam, and in the low speed stage, one of the two intake valves is stopped according to the valve stop cam and the other is driven by the valve drive cam. can do.
According to this, in the low-speed stage, while the swirl is generated, the mixture of fuel and air is promoted, and the air-fuel mixture is distributed in a layered manner, so that the fuel-rich air-fuel mixture can be unevenly distributed in the vicinity of the spark plug. . Then, the speed of flame propagation after ignition can be increased, and lean combustion is realized.

[0027]

By the way, in the case of the two-stage variable valve timing mechanism as described above, in which the intake is performed by only one valve in the low speed stage,
When driving the valve, since is performed by a single valve drive cam, Bal <br/> blanking opening-closing characteristic of the case for opening and closing the intake valve is only one type.

Therefore, if the valve opening / closing characteristic is set for low speed as shown by the curve 3a 'in FIG. 17, for example,
During high speed rotation, both intake valves open and close with low speed opening / closing characteristics, so sufficient torque characteristics cannot be obtained in the high speed rotation range. For example, when mounted on an automobile, the engine can rotate at a high speed sufficient for practical use. Performance cannot be obtained. Conversely, if this valve opening / closing characteristic is set for high speed as shown by the curve 3b 'in FIG. 17, for example, one of the two intake valves will be in a closed state during low speed rotation, and the other will open / close with this high speed opening / closing characteristic. To do. With this high-speed opening / closing characteristic, the valve opening time is long and the valve lift amount is large. Therefore, if the fuel supplied to the combustion chamber is saved, the fuel concentration becomes too lean and appropriate combustion is difficult to perform.

Therefore, it is conceivable to combine the above-mentioned three-stage variable valve timing mechanism (see FIGS. 19 to 23) with this one-valve driving system at low speed. That is, FIG.
One of the low speed cams 3a ', 3a' shown in FIG. 0 is formed as a valve stop cam close to the base circle, and in the low speed stage, one of the intake valves is stopped according to this valve stop cam and the other is operated at low speed. It is driven according to the working cam 3a '. Further, in the medium speed stage, the drive system of one intake valve is switched and driven according to the high speed drive cam, and the other is driven according to the low speed cam 3a '. In the high-speed stage, the drive system of the other intake valve is also switched so that both intake valves are driven according to the high-speed drive cam.

As a result, at the time of high speed rotation, both of the two intake valves open and close with the opening / closing characteristics for high speed, so that the high speed rotation performance of the engine which is sufficient for practical use can be obtained, and at the time of low speed rotation, only one intake valve can be used. Since the open / close drive is performed with the open / close characteristic for low speed, the swirl flow can be used to save the fuel supplied to the combustion chamber, and to perform the appropriate combustion while keeping the fuel concentration to the extent that it does not become too lean.

However, in the case of such a three-stage structure, at the time of medium speed rotation, one intake valve has a high-speed opening / closing characteristic, and the other intake valve has a low-speed opening / closing characteristic, so that they open and close with different characteristics. Such opening and closing of the two valves in different modes makes it difficult to control the fuel supply timing and the like, and may also impair the stability of combustion.

The present invention has been proposed in view of the above problems, and enables easy control of the engine and safe combustion.
Maximum output of engine while ensuring qualitativeness
It is an object of the present invention to provide an engine with a variable valve timing mechanism, which is capable of achieving a significant improvement in fuel consumption while ensuring sufficient fuel consumption.

[0033]

For this reason, claim 1
The engine with variable valve timing mechanism of the present invention is
Two intake valves, a first intake valve and a second intake valve, and a low speed
Engine with cam profile for hour valve timing
For low speed rotation that corresponds to the rotation of the crankshaft
Cam and cam profile for valve timing at low speed
Cam profile for high speed valve timing including
To rotate in response to the rotation of the crankshaft.
A high speed cam and a rocker pivotally mounted on the required part of the engine.
Directly on the shaft and the low speed cam and high speed cam
So that it does not come into contact but rotates around the rocker shaft
Is provided and is in contact with the first intake valve
A first rocker arm that drives the intake valve to open and close, and for the low speed
A low-speed cam having a low-speed roller capable of contacting the cam
Can swing in response to the cam profile of
A second air intake valve that contacts the second air intake valve and drives the second air intake valve to open and close.
No. 2 rocker arm and a high-speed rocker that contacts the high-speed cam.
Is compatible with the cam profile of the high-speed cam.
Rocker arm that swings and rocks, and the third rocker arm
Do not link the first and second rocker arms above
It is possible to switch between the non-coordination mode and the coordination mode in which the coordination is performed.
The mode switching means and the mode depending on the rotation state of the engine.
Control means for controlling the state of the mode switching means.
It is characterized by that. The variable valve timing mechanism with an engine of the present invention according to claim 2, the two intake valves of the first intake valve and a second intake valve, an engine equipped with a cam profile for low-speed valve timing crank A low speed cam that rotates according to the rotation of the shaft,
A high-speed cam having a cam profile for high-speed valve timing including a cam profile for low-speed valve timing, which rotates in response to rotation of the crankshaft, and a rocker pivotally supported on a required portion of the engine. The shaft and the low speed cam and the high speed cam do not directly contact but are provided so as to rotate around the rocker shaft and contact the first intake valve to open and close the first intake valve. A first rocker arm to be driven and a low speed roller that can come into contact with the low speed cam can be swung in accordance with the cam profile of the low speed cam, and the second rocker arm can be brought into contact with the second intake valve. A second rocker arm for driving the second intake valve to open and close, and a third rocker arm for rocking corresponding to the cam profile of the high-speed cam by providing a high-speed roller for contacting the high-speed cam If, first the second rocker arm
First mode switching means capable of switching between a non-coordination mode in which the rocker arm is not linked and a linkage mode in which the rocker arm is linked, and a linkage for linking the third rocker arm to the non-coupling mode not linked to the first and second rocker arms. A second mode switching means capable of switching the mode, and a control means for controlling the states of the first mode switching means and the second mode switching means according to the rotation state of the engine. It has a feature.

Further, the variable valve timing mechanism with an engine of the present invention according to claim 3, in addition to the second aspect, wherein, the rocker arm of the second rocker arm and said third, both on the rocker shaft A first piston chamber rotatably mounted on the rocker shaft, the first mode switching means being formed on the rocker shaft, and having an opening exposed on the outer peripheral surface of the rocker shaft; and the side of the second rocker arm. A first recess formed in the first piston chamber and aligned with the opening of the first piston chamber when the relative phase between the second rocker arm and the rocker shaft is in a predetermined state; and the rocker shaft in the first piston chamber. Of the rocker shaft, the one end of which is inserted so as to be movable in a direction orthogonal to the axis of the rocker shaft and one end of which is projected from the outer peripheral surface of the rocker shaft and is fitted into the first recess and the one end of which is the rocker And a first drive mechanism that drives the first piston between the projecting position and the retracted position. At the same time, the second mode switching means is formed on the rocker shaft and has a second piston chamber having an opening exposed at the outer peripheral surface of the rocker shaft, and the third rocker arm is formed on the side of the third rocker arm. A second recess that is aligned with the opening of the second piston chamber when the relative phase of the rocker arm and the rocker shaft is in a predetermined state, and is orthogonal to the axis of the rocker shaft in the second piston chamber. A protruding position where one end of the rocker shaft is inserted so as to be movable in the direction and the one end of the rocker shaft is protruded from the outer peripheral face of the rocker shaft, and the one end is not protruded from the outer peripheral face of the rocker shaft. When A second piston that can be taken, is characterized by being configured to include a second drive mechanism for driving between the exit projecting the second piston position and the storage position.

Further, the variable valve timing mechanism with an engine of the present invention described in claim 4, in addition to the configuration of claim 3, wherein said first drive mechanism, the first piston the storage position side or First biasing means for biasing to the projecting position side and hydraulically driving the first piston to the projecting position side or the storage position side against the first biasing means. And a first oil pressure supply means capable of supplying a required oil pressure into the first oil chamber when the engine is in a required rotation state. Drive mechanism for urging the second piston toward the storage position side or the protruding position side and the second piston against the second urging means. A second oil chamber formed to be hydraulically driven to the protruding position side or the storage position side and the engine are required. It is characterized by being configured to include a second hydraulic pressure supply means capable of supplying the required oil pressure to the oil chamber of the second when the rotational state.

According to a fifth aspect of the present invention, there is provided an engine with a variable valve timing mechanism according to the fourth aspect , wherein the first urging means and the second urging means have the first and second urging means. Both the first piston and the second piston are urged toward the storage position side, and the first hydraulic pressure supply means is required in the first oil chamber when the engine is in the medium speed and high speed rotation states. And the second hydraulic pressure supply means is set to supply a required hydraulic pressure into the second oil chamber when the engine is in a high speed rotation state. Is characterized by.

In the engine with a variable valve timing mechanism according to a sixth aspect of the present invention, in addition to the configuration according to the fifth aspect , both the first hydraulic pressure supply means and the second hydraulic pressure supply means are provided. It is characterized in that an engine pump driven by the engine is used as a hydraulic pressure source. Also,
An engine with a variable valve timing mechanism according to a seventh aspect of the present invention is, in addition to the configuration according to the second aspect , the control means has a rotational speed range of the engine in a low speed range, a middle speed range, or a high speed range. Is set to control the states of the first mode switching means and the second mode switching means depending on whether the engine is in the range, and when the engine is in the low rotation speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is set to a non-coupling mode in which the second rocker arm is not linked to the first rocker arm, and the third rocker arm is set to the first and the first mode. A two-valve low-speed operating state in which the first intake valve is closed and the second intake valve is opened / closed in accordance with the cam profile of the low-speed cam by setting the non-coupling mode in which the second rocker arm is not linked. When the engine is in the medium speed range, the second mode switching means and the second mode switching means are used to drive the second mode.
Of the first intake valve by setting the rocker arm of the first rocker arm to the first and second rocker arms in the linkage mode and setting the third rocker arm to the non-coupling mode in which the rocker arm is not linked to the first and second rocker arms. And both of the second intake valves are opened and closed in correspondence with the cam profile of the low speed cam to operate in a two-valve low speed mode, and when the engine is in the high speed rotation range, the first mode switching means and the first mode switching means The second rocker arm is set to a linking mode in which the second rocker arm is linked to the first rocker arm and the third rocker arm is set to a linking mode in which the first and second rocker arms are linked to each other through the second mode switching means. So that both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the high-speed cam so as to be in a two-valve high-speed operating state. It is characterized in that it is a constant.

According to the eighth aspect of the present invention, in addition to the structure of the seventh aspect , the engine with a variable valve timing mechanism further includes the first intake valve and the second intake valve in a downstream portion of an intake passage of the engine. Fuel injection means for injecting fuel toward both sides of the intake valve, and fuel injection guide means for deflecting fuel injected from an injection hole of the fuel injection means to the side of the second intake valve, And a fuel injection guide switching unit that operates the fuel injection guide unit when the first intake valve is closed and stops the fuel injection guide unit when the first intake valve operates. I am trying.

According to the ninth aspect of the present invention, in addition to the structure of the eighth aspect , the engine with a variable valve timing mechanism is provided in the intake passage from an upstream portion to a downstream portion of the intake passage. The intake bypass passage and an opening / closing valve for opening and closing the intake bypass passage are attached, and the downstream end of the intake bypass passage is connected to the fuel injection guide means. The fuel injection guide means is configured to deflect the fuel injected from the injection hole toward the second intake valve by injecting intake air guided by the intake bypass passage in a required direction. The on-off valve is used as the switching means.

Further, in the engine with variable valve timing mechanism according to the present invention of claim 10 , in addition to the configuration of claim 2 , the third rocker arm includes the first rocker arm and the second rocker arm. It is characterized by being installed between.

[0041]

The variable valve tie according to the present invention as set forth in claim 1 described above.
In an engine with a rocking mechanism, the control means
The state of the mode switching means is controlled according to the rotation state. This
As a result, the third rocker is passed through the mode switching means.
Do not link the first and second rocker arms above
When the non-coordination mode is set, the third rocker arm
Movement is transmitted to the first and second rocker arms described above.
Disappear. Therefore, a low speed is applied to the first rocker arm.
Although neither the movement of the cam for high speed nor the movement of the high speed cam is transmitted,
The second rocker arm has its low-speed roller connected to the low-speed cam.
While contacting the
Swing according to the cam profile for
The intake valve is opened and closed at low valve timing. Well
Also, the third rocker arm is connected through the mode switching means.
Linking module for linking the first and second rocker arms described above.
When the card is set, the movement of the third rocker arm is
Is transmitted to the first and second rocker arms described above,
Rocker arm, the first rocker arm, and the second rocker
The arm and the arm swing together, and
Each of the first and second rocker arms has a valve timing at the low speed.
Valve timing at high speed including cam profile for steering
The movement of a high-speed cam with a cam profile for
In response to the cam profile for valve timing at high speed
Therefore, they swing together and make the corresponding intake valves move at high speed.
Open / close drive at the lube timing. In the engine with the variable valve timing mechanism according to the first aspect of the present invention,
The control means controls the states of the first mode switching means and the second mode switching means according to the rotation state of the engine.
As a result, a non-coupling mode in which the second rocker arm is not linked to the first rocker arm is set through the first mode switching means, and the third rocker arm is connected to the first and second rocker arms through the second mode switching means. When the non-coordination mode in which the second rocker arm is not linked is set, neither the movement of the second rocker arm nor the movement of the third rocker arm is transmitted to the first rocker arm, and the second rocker arm and the third rocker arm are not transmitted. There is no linkage with the rocker arm.

Therefore, although neither the movement of the low speed cam nor the movement of the high speed cam is transmitted to the first rocker arm,
The second rocker arm swings according to the cam profile for the low speed valve timing of the low speed cam while abutting the low speed roller to the low speed cam to move the corresponding intake valve to the low speed valve timing. Open and close with.

Further, a linking mode for linking the second rocker arm to the first rocker arm is set through the first mode switching means, and the third rocker arm is set to the above-mentioned third mode through the second mode switching means. When the non-coordination mode in which the first and second rocker arms are not linked is set,
The movement of the second rocker arm is transmitted to the first rocker arm. However, the third rocker arm does not cooperate with the above-mentioned first and second rocker arms.

Therefore, the movement of the low speed cam is transmitted to the first rocker arm through the second rocker arm, and both the first rocker arm and the second rocker arm have the low speed valve of the low speed cam. It swings according to the timing cam profile, and opens and closes the corresponding intake valves at low speed valve timing. Further, a linking mode for linking the second rocker arm to the first rocker arm is set through the first mode switching means, and the third rocker arm is linked to the first and the third rocker arms through the second mode switching means. When the link mode for linking the two rocker arms is set, the second rocker arm, the third rocker arm, and the first rocker arm swing together.

Then, the second rocker arm, the third rocker arm, and the first rocker arm are provided with a cam profile for high speed valve timing including a cam profile for valve timing at low speed. In response to the movement of the intake valve, it swings integrally according to the cam profile for high speed valve timing, and the corresponding intake valves are opened and closed at the high speed valve timing.

In the engine with variable valve timing mechanism according to the third aspect of the present invention, the first mode switching means is brought into the linked mode by the first drive mechanism through the first piston chamber. One end of the first piston of the second rocker shaft is projected from the outer peripheral surface of the rocker shaft to
Of the rocker arm into the first recess in the protruding position. This causes the second rocker arm to rotate about the rocker shaft through the engagement of the first piston and the first recess.

In order to bring the first mode switching means into the non-coupling mode, one end of the first piston in the first piston chamber is projected from the outer peripheral surface of the rocker shaft through the first drive mechanism. Set it to a storage position that does not allow it. This disengages the first piston from the first recess and allows the second rocker arm to rotate with respect to the rocker shaft.

In order to bring the second mode switching means into the linked mode, one end of the second piston in the second piston chamber is moved from the outer peripheral surface of the rocker shaft through the second drive mechanism. The third rocker arm is projected so as to be in the projecting position fitted in the second recess of the third rocker arm. This causes the third rocker arm to rotate about the rocker shaft through the engagement of the second piston and the second recess. In order to put the second mode switching means in the non-coupling mode, the second drive mechanism is used to prevent the one end of the second piston in the second piston chamber from protruding from the outer peripheral surface of the rocker shaft. To This disengages the second piston from the second recess and allows the third rocker arm to rotate with respect to the rocker shaft.

In the engine with a variable valve timing mechanism according to the fourth aspect of the present invention, the first drive mechanism and the second drive mechanism operate as follows. In the first drive mechanism, when the first hydraulic pressure supply means does not supply the required hydraulic pressure into the first oil chamber, the first piston is moved by the first biasing means to the storage position side or It is urged toward the protruding position.

Further, when the engine is in a required rotation state, the first hydraulic pressure supply means supplies a required hydraulic pressure into the first oil chamber. Then, the first piston is hydraulically driven to the protruding position side or the storage position side against the biasing force of the first biasing means. Therefore, if the first piston is in the retracted position, it is driven to the protruding position,
If the piston is in the projecting position, it is driven to the retracted position.

In the second drive mechanism, when the second hydraulic pressure supply means does not supply the required hydraulic pressure into the second oil chamber, the second piston is stored by the second biasing means. It is urged toward the position side or the protruding position side. Further, when the engine is in the required rotation state, the second hydraulic pressure supply means supplies the required hydraulic pressure into the second oil chamber. Then, the second piston is hydraulically driven to the protruding position side or the storage position side against the biasing force of the second biasing means. Therefore, if the second piston is in the retracted position, it is driven to the projecting position, and if the second piston is in the projecting position, it is driven to the retracted position.

In the engine with the variable valve timing mechanism according to the fifth aspect of the present invention, when the engine is in the low speed rotation state, the first hydraulic pressure supply means and the second hydraulic pressure supply means operate as the first hydraulic pressure supply means. The required hydraulic pressure is not supplied to the oil chamber and the second oil chamber. Therefore, the first
The first piston and the second piston are both in the retracted position by the urging force of the first urging means and the second urging means.

This disengages the first piston from the first recess and puts the second rocker arm into a non-coupling mode rotatable with respect to the first rocker arm. And the second piston disengages from the second recess and the third rocker arm is in a non-coupling mode rotatable relative to the first and second rocker arms. Become.

Further, when the engine is in the middle speed rotation state, the required hydraulic pressure is not supplied from the second hydraulic pressure supply means to the second hydraulic chamber, but from the first hydraulic pressure supply means. A required hydraulic pressure is supplied to the first oil chamber.
Therefore, the second piston is in the retracted position due to the urging force of the second urging means, while the first piston is in the projecting position due to the hydraulic pressure in the first oil chamber.

As a result, the first piston is engaged with the first recess, and the second rocker arm is brought into the state of the linkage mode in which the second rocker arm is linked with the first rocker arm, and the second rocker arm is brought into the linkage mode.
The piston is no longer engaged with the second recess,
The rocker arm is in a non-coupling mode in which the rocker arm is rotatable with respect to the first and second rocker arms. Further, when the engine is in a high-speed rotation state, a required hydraulic pressure is supplied from the first hydraulic pressure supply means and the second hydraulic pressure supply means to the first oil chamber and the second oil chamber.

Therefore, the first piston and the second piston
Of the second oil chamber and the second oil chamber, respectively.
Due to the oil pressure in the oil chamber, it is in the protruding position. As a result, the first piston engages with the first recess, the second rocker arm is brought into a linking mode in which it links with the first rocker arm, and the second piston By engaging the second recess, the third rocker arm is also in the linking mode in which it links with the first and second rocker arms.

In the engine with variable valve timing mechanism according to the sixth aspect of the present invention, both the first hydraulic pressure supply means and the second hydraulic pressure supply means hydraulically drive the engine pump driven by the engine. Supply hydraulic pressure as a source. In the engine with a variable valve timing mechanism according to the present invention described in claim 7 , the control means determines whether the rotational speed range of the engine is in a low speed range, a medium speed range, or a high speed range. The states of the first mode switching means and the second mode switching means are controlled.

Then, when the engine is in the low speed range, the second rocker arm is brought into the non-coupling mode in which the second rocker arm is not linked to the first rocker arm through the first mode switching means and the second mode switching means. At the same time, the third rocker arm is set to the non-coupling mode in which the third rocker arm is not linked to the first and second rocker arms. As a result, the one-valve low speed operating state is achieved in which the first intake valve is closed and the second intake valve is opened / closed in accordance with the cam profile of the low speed cam.

When the engine is in the medium speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is brought into a linkage mode in which the second rocker arm is linked to the first rocker arm, and the third rocker arm is linked to the first and second portions. The non-coordination mode is set so that the rocker arm of is not linked. As a result, a two-valve low-speed operating state is established in which both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the low-speed cam.

When the engine is in the high speed range,
Through the first mode switching means and the second mode switching means, the second rocker arm is brought into a linkage mode in which the second rocker arm is linked to the first rocker arm, and the third rocker arm is linked to the first and second portions. The link mode is set to link to the rocker arm of. As a result, a two-valve high-speed operating state is established in which both the first intake valve and the second intake valve are opened and closed in accordance with the cam profile of the high-speed cam.

In the engine with variable valve timing mechanism according to the present invention described in claim 8 above, when the first intake valve is closed, the fuel injection guide switching means switches the fuel injection guide means to operate. To be Therefore, when the fuel injection means injects fuel from the injection hole toward both sides of the first intake valve and the second intake valve in the downstream portion of the intake passage of the engine, the fuel injection is performed. The fuel injected from the injection hole is deflected to the side of the second intake valve by the guide means.

Therefore, fuel is not injected into the first intake valve which is closed. Further, when the first intake valve is in operation, the fuel injection guide switching means switches the fuel injection guide means to stop. For this reason,
Fuel injection means, in the downstream portion of the intake passage of the engine,
When the fuel is injected from the injection hole toward both sides of the first intake valve and the second intake valve, the fuel injected from the injection hole is directly injected into the first intake valve and the second intake valve. Supplied on both sides of the intake valve.

In the engine with variable valve timing mechanism according to the present invention described in claim 9 , the idle rotation speed adjusting means adjusts the idle rotation speed of the engine while opening and closing the intake bypass passage through the opening / closing valve. When the first intake valve is closed, the on-off valve is opened, and a part of the intake air is guided to an intake bypass passage provided from the upstream portion to the downstream portion of the intake passage.

Then, the intake air introduced into the intake bypass passage is injected from the downstream end of the intake bypass passage through the fuel injection guide means, and the fuel injected from the injection hole is supplied to the side of the second intake valve. Deflected to. In the engine with variable valve timing mechanism of the present invention according to claim 10 described above,
Since the third rocker arm is interposed between the first rocker arm and the second rocker arm, the third rocker arm is
The respective distances between the rocker arm and the first rocker arm and between the third rocker arm and the second rocker arm can be shortened, and torsional deformation and the like between them can be suppressed.

[0065]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 12 show an engine with a variable valve timing mechanism as a first embodiment of the present invention.
1 is a perspective view of the valve operating system, FIG. 2 is a sectional view showing the variable valve timing mechanism, FIG. 3 is a sectional view showing the variable valve timing mechanism, and FIG. 4 is a schematic sectional view of the intake passage portion. 5, FIG. 5 is a cross-sectional view of an essential part of the intake passage portion, FIG. 6 is a view showing an air injection port member provided in the intake passage portion, and FIG.
8 is a diagram showing the output characteristic of the present engine, FIG. 9 is a diagram showing the valve lift state thereof, and FIGS. 10-12 are diagrams showing the operation of the variable valve timing mechanism. In addition, FIG.
16 shows an engine with a variable valve timing mechanism as a second embodiment of the present invention, FIG. 13 is a sectional view showing the variable valve timing mechanism, and FIGS. 14 to 16 are views showing the operation of the variable valve timing mechanism. Is.

First, the first embodiment will be described. The valve operating system of this embodiment is provided with a first intake valve 3 and a second intake valve 2 as a pair, as shown in FIG. A valve train is configured to open and close the intake valves 2 and 3. This valve train is directly driven by a base circular cam (hereinafter referred to as base circle) 10 and cams 12 and 13 which rotate in response to rotation of an engine crankshaft, and these cams 12 and 13. Rocker arms 14 and 15 and a rocker arm 6 indirectly driven via the rocker arm 14 or 15.

The base circle 10 and the cams 12 and 13 are both provided on the cam shaft 11 which rotates in conjunction with the rotation of the crankshaft of the engine. The cam 12 is a low-speed cam having a cam profile for low-speed valve timing, and the cam 13 is a high-speed cam having a high-speed valve timing cam profile. They have the same base circle diameter. The cam profiles of the low speed cam 12 and the high speed cam 13 have valve lift characteristics as shown in FIG. 9, and the cam profile of the high speed cam 13 is the same as that of the low speed cam 12. It is set to include.

The first rocker arm 6 is a main rocker arm that is in contact with the intake valve 3 and is directly involved in the opening / closing operation of the intake valve 3. Also, the second and third rocker arms 1
Reference numerals 4 and 15 are rocker arms with rollers.
The second rocker arm 14 is a main rocker arm that contacts the intake valve 2 and is directly involved in opening / closing driving of the intake valve 2. The third rocker arm 15 includes the intake valves 2, 3
Is a sub-rocker arm indirectly involved in opening / closing driving of the intake valves 2 and 3 without abutting against.

The main rocker arm 6 is provided integrally with the rocker shaft 16 as shown in FIG. The rocker shaft 16 is pivotally supported by a bearing portion 1A provided on a cylinder head or the like (not shown) of the engine, and the main rocker arm 14 can swing together with the rocker shaft 16. The main rocker arm 6 is provided with a screw mounting portion 6B at its swinging end portion 6A, and an adjusting screw 22 that comes into contact with the stem end portion of the intake valve 3 is screwed into this mounting portion 6B. . 22A is an adjusting nut.

Further, as shown in FIG. 1, a contact surface 6C capable of contacting the base circle 10 is provided at an intermediate portion of the main rocker arm 6, and a hydraulic piston mechanism 17 as a second mode switching means described later is provided. Alternatively, when the hydraulic piston mechanism 27 as the first mode switching means is set to the linkage mode, the contact surface 6C is separated from the base circle 10 and swings in conjunction with the main rocker arm 14 or the sub-rocker arm 15. It has become.

As shown in FIG. 2, the main rocker arm 14 is rotatably supported on the rocker shaft 16 and has a swing end 14A provided with a screw mounting portion 14B. . Then, the adjusting screw 21 that comes into contact with the stem end of the intake valve 2 is screwed to the mounting portion 14B. In addition, 21A is an adjustment nut.

As shown in FIGS. 1 and 2, an intermediate portion of the main rocker arm 14 is provided with a low speed roller 18 capable of contacting the low speed cam 12. This low speed roller 18
Is a shaft 1 pivotally supported in the middle of the main rocker arm 14.
It is pivotally supported by 8A via a roller bearing 18B so that it can smoothly rotate. This main rocker arm 1
The hydraulic piston mechanism 27 described above is provided between the rocker shaft 4 and the rocker shaft 16. This hydraulic piston mechanism 2
7 is a mode in which the main rocker arm 14 is rotatable with respect to the rocker shaft 16 and does not work in association with the rocker shaft 16 (that is, the main rocker arm 6) (uncoupling mode), and the main rocker arm 14 rotates integrally with the rocker shaft 16. Then, it can be set to any one of a mode (coordination mode) in which the main rocker arm 14 is linked to operate.

On the other hand, as shown in FIG. 2, the sub-rocker arm 15 is rotatably supported at its cylindrical base portion 15B so as to be rotatable with respect to the rocker shaft 16, and its swing end portion 15A is provided for high speed. A high speed roller 19 that can come into contact with the cam 13 is provided. As shown in FIGS. 1 to 3, the high-speed roller 19 also includes a roller bearing 19B on a shaft 19A that is rotatably supported by the swing end 15A of the sub-rocker arm 15.
It is pivoted so that it can rotate smoothly through.

Further, between the sub-rocker arm 15 and the rocker shaft 16, the above-mentioned hydraulic piston mechanism 17 is provided.
Is provided. The hydraulic piston mechanism 17 has a mode in which the sub-rocker arm 15 is rotatable with respect to the rocker shaft 16 and does not work in cooperation with the main rocker arm 14 (non-coupling mode), and the sub-rocker arm 15 rotates integrally with the rocker shaft 16 to perform main operation. Rocker arm 14
Can be set to any one of a mode (coordination mode) in which the link operation is performed.

Then, the hydraulic piston mechanism 1 of this embodiment
7, 27 have the same structure as each other as shown in FIGS. That is, the hydraulic piston mechanisms 17, 27 are
Piston chambers 17F, 2 formed in the rocker shaft 16
The pistons 17A and 27A are movably arranged in the diametrical direction of the rocker shaft 16 in 7F, and the pistons 17A and 27A are respectively placed in a position stored in the rocker shaft 16 and a position protruding from the rocker shaft 16. It has driving mechanisms 17J and 27J for driving them.

The drive mechanisms 17J and 27J are pistons 17
Springs 17B and 27B as biasing means for biasing A and 27A toward the storage position, and oil chambers 17G and 2 for hydraulically driving the pistons 17A and 27A toward the protruding position.
7G and means for supplying hydraulic pressure to the oil chambers 17G, 27G. That is, the other end of the piston 17A (the upper end in FIGS. 2 and 3, hereinafter, this end will be referred to as the tip) can enter the required position of the cylindrical base 15B of the sub-rocker arm 15. A recess 17C is formed, and the other end of the piston 27A (the upper end in FIG. 2, which is hereinafter referred to as the tip) is formed at a required position of the cylindrical base 14C of the main rocker arm 14. A recess 27C that can enter is formed. Note that 17E and 27E are lid members that form the recess 17C.

Collar-shaped portions 17H and 27H are formed on the outer circumferences of the base end portions of the pistons 17A and 27A, and step portions 17I and 27I are provided on the inner wall of the piston chamber.
Springs 17B and 27B are interposed in a compressed state between the collar-shaped portions 17H and 27H and the step portions 17I and 27I. Therefore, these pistons 17A, 27
A is urged to the storage position on the base end side by springs 17B and 27B.

Further, one end of the pistons 17A, 27A (the lower end in FIGS. 2 and 3, and this end is hereinafter referred to as the base end) and the sub-rocker arm 15 or the cylindrical base 15B of the main rocker arm 14. Oil chambers 17G and 27G are formed between the inner peripheral surface of 14C and the inner peripheral surface of 14C. Piston 17A,
Oil holes 17D and 27D are formed inside 27A to connect the oil passages 16A and 16B formed in the axial center portion of the rocker shaft 16 and the oil chambers 17G and 27G.

The oil chamber 17G is connected to the oil passage 16A of the rocker shaft 16 and the oil hole 17 of the piston 17A.
Hydraulic oil is introduced from D, and the oil passage 16B of the rocker shaft 16 and the oil hole 2 of the piston 27A are introduced into the oil chamber 27G.
The hydraulic oil is introduced from 7D. As a result, when the hydraulic oil is supplied to the oil chamber 17G, the piston 1 is resisted against the biasing force of the spring 17B as shown in FIG.
7A is driven toward the tip end side, and the tip end portion of the piston 17A comes to a protruding position where it is fitted into the recess 17C. On the other hand, oil chamber 1
When the supply of hydraulic oil to 7G is cut off, the piston 1 is urged by the urging force of the spring 17B as shown in FIGS.
7A is driven to the base end side, and the tip end portion of the piston 17A comes to the retracted position where it is removed from the recess 17C.

That is, in the hydraulic piston mechanism 17, when the hydraulic oil is supplied to the oil chamber 17G, the sub-rocker arm 15 is fitted into the recess 17C at the tip of the piston 17A.
Becomes a mode (coordination mode) in which it rotates integrally with the rocker shaft 16 and cooperates with the main rocker arm 6, and when the supply of hydraulic oil to the oil chamber 17G is cut off, the piston 17A is detached from the recess 17C at the tip, The sub-rocker arm 15 is set so as to be rotatable with respect to the rocker shaft 16 and not to operate in cooperation with the main rocker arm 6 (non-cooperation mode).

When hydraulic oil is supplied to the oil chamber 27G, as shown in FIGS. 10 and 11, the piston 27A is driven toward the tip end side against the biasing force of the spring 27B,
The tip of the piston 27A fits into the recess 27C. On the other hand, when the supply of hydraulic oil to the oil chamber 27G is cut off, as shown in FIG. 12, the piston 27A is driven toward the base end side by the urging force of the spring 27B, and the tip end portion of the piston 27A moves from the recess 27C. I'm supposed to take it off.

That is, in the hydraulic piston mechanism 27, when the hydraulic oil is supplied to the oil chamber 27G, the piston 27A is fitted into the recess 27C, so that the main rocker arm 1 is moved.
4 becomes a mode in which the main rocker arm 14 and the main rocker arm 6 cooperate with each other by rotating integrally with the rocker shaft 16 and the supply of hydraulic oil to the oil chamber 27G is cut off. The main rocker arm 14 is rotatable with respect to the rocker shaft 16 when the main rocker arm 1 is detached from the main rocker arm 1.
4 and the main rocker arm 6 are set so as to be in a mode in which the main rocker arm 6 and the main rocker arm 6 do not cooperate (non-cooperative mode).

The sub-rocker arm 15 is shown in FIGS.
As shown in FIG. 4, the main rocker arms 6 and 14 are arranged between the two main rocker arms 6 and 14, and the distance between the main rocker arms 6 and 14 is short. As a result, even when the main rocker arms 6 and 14 are driven at high speed via the sub-rocker arm 15, a slight twisting deformation is less likely to occur.

The hydraulic oil is supplied to the above-mentioned oil chambers 17G and 27G by the hydraulic oil supply system 5 as schematically shown in FIG.
It is supposed to be done through 1. The hydraulic oil supply system 51 includes a hydraulic pump (engine pump) 52 driven by an engine, and pressure adjusting means 53 for adjusting the hydraulic oil pressurized by the hydraulic pump 52 to a required hydraulic pressure.
The hydraulic oil whose pressure is adjusted by the pressure adjusting means 53 is supplied to the oil passage 16 described above.
It is provided with a switching valve 54 capable of switching between a supply state in which it is supplied to the oil chambers 17G and 27G through A and 16B and a supply stopped state in which it is not supplied.

The switching valve 54 is composed of, for example, a solenoid valve and has an electronic control unit (ECU) as a control means.
The switching valve 54 can be electronically controlled by 50. As a result, for example, as shown in FIG. 8, the switching point C corresponding to the engine speed, output torque, etc.
By setting 1 and C2, the modes of the hydraulic piston mechanisms 17 and 27 can be switched according to the engine speed and the output torque.

That is, in FIG. 8, both hydraulic piston mechanisms 17 and 27 are provided in a region where the engine speed and output torque are smaller than the switching point C1 (regions to the left and below the straight line of the switching point C1 in the figure). So that both are in the non-coordination mode.
No hydraulic pressure is supplied to 7. As a result, the one-valve low speed operation state (low speed stage) is realized.

In addition, the region where the engine speed and the output torque are between the switching point C1 and the switching point C2 (in the figure, the switching point C
1 and C2), the hydraulic piston mechanism 2
The switching valve 54 is set to a state in which hydraulic pressure is not supplied to the hydraulic piston mechanism 17 but hydraulic pressure is supplied to the hydraulic piston mechanism 27 so that the hydraulic piston mechanism 17 is in the cooperative mode and the hydraulic piston mechanism 17 is in the non-coordinated mode. As a result, a 2-valve low speed operation state (medium speed stage) is realized.

In a region where the engine speed and the output torque are larger than the switching point C2 (regions to the right and above the straight line of the switching point C2 in the figure), both hydraulic piston mechanisms 1 are provided.
The switching valve 54 is brought into a state of supplying hydraulic pressure to both hydraulic piston mechanisms 17 and 27 so that both 7 and 27 are in the linked mode. As a result, a 2-valve high-speed operating state (high-speed stage) is realized.

As shown in FIG. 3, a spring retainer 5A is provided on the upper end of the valve stem 3A of the intake valve 3, and a spring retainer 5B is provided on the cylinder head 1 side. 5
A valve spring 4 is interposed between B and B. As a result, the intake valve 3 is biased in the closing direction, that is, toward the upper end of the valve stem 3A. Therefore, the main rocker arm 6 also receives the base circle 1 through the valve spring 4.
The valve spring 4 is biased to the 0 side and acts as a restoring force when the main rocker arm 6 swings.

Although not shown, the intake valve 2 has the same structure as the intake valve 3, and the main rocker arm 14 is also urged toward the cam 12 through a valve spring (not shown) so that the urging force of the valve spring is increased. It acts as a restoring force when the main rocker arm 14 swings. On the other hand, the sub rocker arm 15
In the linkage mode, the main rocker arm 14 is integrated and receives the urging force of the valve spring 4, but in the non-coupling mode, the urging force is not received. Therefore, a means for urging the cam 13 side is provided, and the sub-rocker arm 15 is It is necessary to be able to follow the cam 13. Therefore, the sub-rocker arm 15 is provided with an arm spring mechanism 20.

[0091] The arm spring mechanism 20, as shown in FIG. 3, have a shown installed in a cylinder head, etc.
An outer case 20A secured to the Holder, the inner case 20B provided so as not to leave from and the outer case 20A movable back and forth within the outer case 20A,
The spring 20C interposed between the outer case 20A and the inner case 20B, and the inner case 20
And a contact portion 20D formed at the end of B.
The lever portion 15C provided on the sub-rocker arm 15 is in contact with the contact portion 20D, and the arm sp
By the urging force of the spring 20C of the ring mechanism 20,
The sub rocker arm 15 is pressed against the cam 13 side,
A predetermined movement is performed according to the cam 13.

By the way, the intake system 40 of this engine is
It is configured as shown in FIGS. That is, the throttle valve 43 is provided in the intake passage 42 on the downstream side of the air cleaner 41.
And a branched intake manifold 44 for each cylinder is provided downstream of the throttle valve 43. Further, each intake valve 2, is provided downstream of the intake manifold 44.
Intake ports 44A and 44B that are bifurcated toward 3
Are formed.

An injector (fuel injection means) 46 is installed on the upstream side of the intake ports 44A, 44B toward the opening of the intake ports 44A, 44B to the combustion chamber 45. The injector 46 is attached to the injector attachment portion 1C of the cylinder head with the direction of the fuel injection hole 46B set so that the fuel can be uniformly injected into the openings of the intake ports 44A and 44B.

An injector guide 49 as fuel injection guide means is provided outside the tip portion 46A of the injector 46. This injector guide 49
As shown in FIGS. 6A, 6B, and 6C, is the tip portion 46A of the injector 46 and the injector mounting portion 1C.
Is interposed between the pipe portion 49A and the base portion 49
C and the pipe portion 49A and the base portion 49C
An air flow path 49B and an air injection port 49D are formed inside the. Then, by injecting air from the air injection port 49D, the fuel injected from the injection hole 46B is deflected to one intake valve 2 side. Therefore,
The directions of the air passage 49B and the air injection port 49D are set in the direction of the intake valve 2.

In this embodiment, as shown in FIG. 6 (C), the air injection port 49D is formed by three holes, but the air injection port is not limited to this. As shown in FIG. 7, an air injection port with an arcuate slit 49E can be considered. However, in FIG. 7, the description of the pipe portion 49A is omitted. Further, in this embodiment, an idle speed adjusting means (idle speed controller; hereinafter abbreviated as ISC) is also used as a means for supplying air to the injector guide 49.
The ISC 47 has an intake bypass passage 48A and an opening / closing valve 47A that opens and closes the intake bypass passage 48A. The intake bypass passage 48A is formed from a portion of the intake passage 42 upstream of the throttle valve 43 to each intake manifold 44, and the opening / closing valve 4 is provided at the upstream opening 48B.
7A is provided. And the intake bypass passage 48A
The downstream opening 48C is directed toward the injector guide 49, and the air passing through the intake bypass passage 48A is ejected from the injector guide 49.

The on-off valve 47A also serves as fuel injection guide switching means for switching the operating state of the injector guide 49, that is, the state of injecting air from the air injection port 49D of the injector guide 49 and the state of not injecting air. That is, the opening / closing valve 47A is opened when the intake valve 3 is closed so that the air is injected from the injector guide 49, and is closed when the intake valve 3 is activated to stop the air injection from the injector guide 49. Operate.

The on-off valve 47A is a solenoid 47B.
The solenoid valve is driven by the ECU 50 and its operation is controlled by the ECU 50. That is, the ECU 50
Controls the opening degree of the on-off valve 47A so that a predetermined idle speed state is achieved when the engine is idle, and the on-off valve 47A is opened when the intake valve 3 is closed (at the time of one valve low speed operation).
Control is performed so that A is opened and air is injected from the intake bypass passage 48A and the injector guide 49.

Further, at the time of operation for one valve low speed, the intake air forms a swirl in the combustion chamber 45 to distribute the air-fuel mixture in a layered manner, so that the fuel-rich air-fuel mixture is unevenly distributed in the vicinity of the spark plug as a whole. Is being used to produce lean fuel with less fuel. Therefore, when this one-valve operation is performed, a correspondingly small amount of fuel is injected from the injector 46.

Although not shown, in this engine,
Like the intake valve, the exhaust valve is also provided as a two-valve pair, and these two exhaust valves are also opened and closed in the low speed mode by the low speed cam at the low speed and at the high speed at the high speed as shown in FIG. It is designed to open and close in high-speed mode by the cam. Since the engine with the variable valve timing mechanism according to the first embodiment of the present invention is configured as described above, the intake valves or the exhaust valves 2 and 3 operate as follows according to the engine speed and the output torque. To do.

That is, as shown in FIG. 8, in the low speed rotation region where the engine speed and the output torque are smaller than the switching point C1, the switching valve 54 causes the hydraulic piston mechanisms 17, 2 to operate.
The hydraulic pressure is not supplied to 7. As a result,
As shown in FIG. 2, the pistons 17A and 27A are urged toward the base end side by springs 17B and 27B, respectively, and the pistons 17A and 27A are held in a state in which their tip ends are removed from the recesses 17C and 27C. To be done.

Therefore, the sub-rocker arm 15 and the main rocker arm 14 are both freely rotatable with respect to the rocker shaft 16 and are in the non-coupling mode in which the sub-rocker arm 16 and the main rocker arm 6 do not work together. As a result, the main rocker arm 14
Is opened / closed according to the low speed cam 12, while the main rocker arm 6 is held in a closed state while contacting the base circle 10, and only the main rocker arm 14 is opened / closed at a low speed valve timing. Low speed stage) is realized.

At this time, the opening / closing valve 47A is opened, and the intake bypass passage 48A and the injector guide 4 are opened.
Air is ejected from the air ejection port 49D of No. 9. And
By the air that is injected against, the fuel injected from the injection hole 46B is deflected to the side of the intake valve 2 that opens and closes.
As a result, fuel is not injected to the side of the intake valve 3 that is at rest, combustion fluctuation due to fuel accumulation on the side of the pause valve is prevented, normal combustion is secured, and deterioration of exhaust gas is also prevented. There is an advantage.

Particularly, in this embodiment, since the fuel injection direction is deflected by utilizing the ISC 47, there is an advantage that such fuel accumulation can be prevented at low cost. In this one-valve low-speed operating state, the intake air can form a strong swirl in the combustion chamber 45, and the intake air can be stratified to partially unevenly distribute the rich fuel mixture in the vicinity of the spark plug. it can. As a result, lean combustion can be realized while stabilizing the combustion without lowering the combustion speed and deteriorating the ignitability, and it is possible to significantly improve the fuel efficiency of the engine and reduce harmful exhaust gas.

As a result, in the one-valve low speed operation state, the output torque of the engine peaked in the low speed rotation range of the engine can be obtained with a small fuel consumption, as shown by the curve a.
Further, in general, when the hydraulic pump 52 is driven by an engine, no hydraulic output is generated at the time of starting. However, in this embodiment, the low speed stage is set to each hydraulic piston mechanism 1
Since this is realized without supplying hydraulic pressure to 7 and 27, the engine can be started in the low speed stage of the one valve low speed operation without requiring hydraulic pressure.

Therefore, when starting the engine, only one valve needs to be operated, and the cranking force of the starter is sufficient to correspond to the valve spring force of only one valve. As a result, there is an advantage that the starter can be downsized.
Further, as shown in FIG. 8, in the medium speed rotation region in which the engine speed and the output torque are larger than the switching point C1 and smaller than the switching point C2, the hydraulic piston mechanism 1 is operated by the switching valve 54.
The hydraulic pressure is not supplied to 7, but the hydraulic piston mechanism 27 is supplied with the hydraulic pressure.

As a result, as shown in FIG. 11, the piston 17A is urged by the spring 17B toward the base end side thereof, and the tip end thereof is held in a state of being released from the recess 17C. On the other hand, due to the hydraulic pressure supplied to the oil chamber 27G, the piston 27A is driven toward the tip end side against the biasing force of the spring 27B, and the tip end portion is fitted into the recess 27C.

Therefore, the main rocker arm 14 is rotated integrally with the rocker shaft 16 to enter the link mode in which the main rocker arm 6 is linked to the main rocker arm 6, and the sub rocker arm 15 is rotatable with respect to the rocker shaft 16 and linked to the main rocker arm 6. Not in non-coordination mode. As a result, the main rocker arms 14 and 6 both open and close according to the low speed cam 12, and the main rocker arm 1
A 2-valve low speed operating state (medium speed stage) in which 4 and 6 are opened and closed at low speed valve timing is realized.

In this two-valve low-speed operating state, the output torque of the engine has a peak in the medium-speed rotation range of the engine, as shown by the curve b. Further, as shown in FIG. 8, in the high speed rotation region where the engine speed and the output torque are larger than the switching point C2, the switching valve 54 causes the hydraulic piston mechanism 17 to operate.
Also, the hydraulic pressure is supplied to the hydraulic piston mechanism 27.

As a result, as shown in FIG. 10, the pistons 27A and 27A are driven toward the tip end side against the urging force of the springs 17B and 27B by the hydraulic pressure in the oil chambers 17G and 27G. The tip is a recess 17C,
Insert into 27C. Therefore, the main rocker arm 1
4 and the sub-rocker arm 15 rotate integrally with the rocker shaft 16 to enter a linkage mode in which the sub-rocker arm 16 and the main rocker arm 6 are linked.

Since the cam profile of the high speed cam 13 is large so as to include the cam profile of the low speed cam 12, both the main rocker arms 14 and 6 are opened and closed according to the high speed cam 13 so that the main rocker arms 14 and 6 are used for high speed. A 2-valve high-speed operating state (high-speed stage) that opens and closes at valve timing is realized. In the two-valve high-speed operating state, the output torque of the engine peaks in the high-speed rotation range of the engine, as indicated by the curve c.

Thus, while switching the intake valves 2 and 3 between the low speed stage, the medium speed stage and the high speed stage, efficient combustion can be realized in a wide rotation range of the engine, especially at low speed rotation. It is possible to achieve significant fuel economy savings due to lean combustion, and to obtain sufficient output in the mid-high speed rotation range. In particular, when the engine rotates at medium speed, both intake valves 2 and 3 open and close with the low-speed opening / closing characteristic, so that control including the timing of fuel supply can be appropriately performed, and combustion stability can be secured.

Further, when the low speed stage and the medium speed stage are switched, one of the intake valves is switched from the rest to the low speed opening / closing, so that the change of the intake can be made gradually near this switching point, and the smooth engine output characteristic can be obtained. Easy to get. Further, in this embodiment, since the hydraulic piston mechanisms 17 and 27 are similarly configured, there is an advantage that the manufacturing cost can be reduced by sharing the parts.

Further, since the sub-rocker arm 15 is arranged between the two main rocker arms 6 and 14, the accuracy is high when the both main rocker arms 6 and 14 are driven at high speed through the sub-rocker arm 15 in the high speed stage. There is also an advantage that the valve is driven well and properly. Next, a second embodiment will be described. In this embodiment, the hydraulic piston mechanism 3 on the main rocker arm 14 side is used.
7 is different from that of the first embodiment.

That is, as shown in FIG. 13, the hydraulic piston mechanism 37 includes a piston 37A movably arranged in the diameter direction of the rocker shaft 16 in a piston chamber 37F formed in the rocker shaft 16. One end of the piston 37A (upper side end portion in FIGS. 2 and 3;
This end is referred to as a tip, and the other end is referred to as a base). .

Further, inside the piston 37A, an oil hole 37D is formed which connects the oil passage 16B formed in the axial center portion of the rocker shaft 16 and the oil chamber 37C. Further, a spring 37B is interposed in a compressed state at the base end of the piston 37A. Incidentally, 37E is a spring retainer. As a result, when the hydraulic oil is supplied to the oil chamber (recess) 37C, the piston 37A is driven to the rear end side against the biasing force of the spring 37B, as shown in FIG. The tip portion is adapted to come out of the recess 37C. On the other hand, when the hydraulic oil supply to the oil chamber 37G is cut off, the piston 37A is driven toward the tip end side by the biasing force of the spring 37B, and the tip end portion of the piston 37A is recessed 37C as shown in FIGS. It is designed to fit in.

That is, in the hydraulic piston mechanism 37, when the hydraulic oil is supplied to the oil chamber (recess) 37C, the piston 37
By detaching the tip end of A from the recess 37C, the main rocker arm 14 is rotatable with respect to the rocker shaft 16, and the main rocker arm 14 and the main rocker arm 6
When and are in a mode in which they do not work together (non-coupling mode), and the supply of hydraulic oil to the oil chamber (recess) 37C is cut off, the main rocker arm 14 is inserted into the recess 37C at the tip of the piston 37A, causing the rocker shaft 14 to move. It is set so that the main rocker arm 14 and the main rocker arm 6 rotate in unison with each other 16 to operate in a coordinated manner (cooperative mode).

The engine having a variable valve timing mechanism according to the second embodiment of the present invention constructed as described above operates in substantially the same manner as that of the first embodiment, except for the hydraulic control of the hydraulic piston mechanism 37. However, almost the same action and effect can be obtained. In each of the above embodiments, the first rocker arm (main rocker arm) 6 is formed integrally with the rocker shaft 16.
It suffices that the rocker arm 6 can rotate around the rocker shaft 16, and when the rocker arm 6 is configured separately from the rocker shaft 16, the rocker arm 6 and the rocker arms 14 and 15 are provided with mode switching means 17 and 27, respectively.
Should be installed. Note that in each of the above-described embodiments, the low speed
Three stays, a tage, a medium-speed stage, and a high-speed stage
Is provided, but for example, abolishing the medium-speed stage
Only two stages, low speed stage and high speed stage
Even with the configuration provided, it is possible to operate at low speed with one valve at low speed.
Saving fuel consumption and operating two valves at high speed for high speed
It is possible to secure the output of the engine by. Of course,
The output characteristics of gin are such that three stages can be switched.
Is not flat, but it is a phase of low fuel consumption and securing output.
It can solve contradictory problems at the same time.

[0118]

As described above in detail , the book according to claim 1
According to the engine with a variable valve timing mechanism of the invention
For example, two intake valves, a first intake valve and a second intake valve,
Equipped with a cam profile for valve timing at low speed
The low rotation that corresponds to the rotation of the engine crankshaft.
High speed cam and cam profile for valve timing at the low speed
Cam profile for valve timing at high speed
Rotation, corresponding to the rotation of the crankshaft.
High speed cam and pivotally supported on the required parts of the engine
For the rocker shaft, the low speed cam and the high speed cam,
It does not come into direct contact, but it rotates around the rocker shaft.
And is in contact with the first intake valve and
A first rocker arm for opening and closing the intake valve of No. 1 and
For low speed rollers that can contact the high speed cam
It can swing according to the cam profile of the cam,
Abut the second intake valve to open / close the second intake valve.
The second rocker arm and the high speed that abuts the high speed cam.
For the high speed cam profile with a roller
And a third rocker arm that swings in response to the rocker arm.
Link the arm to the first and second rocker arms described above.
Switch between non-coordination mode and non-coordination mode
Depending on the rotation mode of the engine
And a control means for controlling the state of the mode switching means.
In this way, the intake valve can
While switching between two stages, the fast stage,
The wide rotation range of the gin enables efficient combustion and low speed
Fuel economy can be saved during rotation and sufficient in high speed range
It will be possible to obtain various output. In addition, claim 2
Engine with Variable Valve Timing Mechanism of the Present Invention Described
According to the above , there are two intake valves, a first intake valve and a second intake valve, and a low speed cam that has a cam profile for low speed valve timing and that rotates in response to rotation of the crankshaft of the engine. A high-speed cam that includes a cam profile for high-speed valve timing including a cam profile for low-speed valve timing and that rotates in response to rotation of the crankshaft, and is pivotally supported by a required portion of the engine. The rocker shaft is provided so as not to directly contact the low speed cam and the high speed cam but to rotate about the rocker shaft and to contact the first intake valve to connect the first intake valve to the first intake valve. A first rocker arm that is driven to open and close, and a low speed roller that can abut the low speed cam are provided so that the rocker can swing in response to the cam profile of the low speed cam and the second intake air. A third rocker arm that abuts on the second intake valve to drive the second intake valve to open and close, and a high-speed roller that abuts the high-speed cam. The third rocker arm swings corresponding to the cam profile of the high-speed cam. The rocker arm, a first mode switching means capable of switching between a non-coupling mode in which the second rocker arm is not linked to the first rocker arm and a linked mode in which the second rocker arm is linked to the first rocker arm, and the third rocker arm having the first and second rocker arms described above. Second mode switching means capable of switching between a non-cooperative mode in which the rocker arm is not linked to the rocker arm and a linked mode in which the rocker arm is linked, and states of the first mode switching means and the second mode switching means according to the rotation state of the engine. With a configuration that includes a control means for controlling the In a wide rotational range of engines, can achieve efficient combustion, can savings in fuel consumption during low-speed rotation, it is possible to obtain a sufficient output in the mid-high speed range.

In particular, since both intake valves can be opened / closed at low speed opening / closing characteristics, for example, when the engine rotates at medium speed, control including the timing of fuel supply can be appropriately performed to ensure combustion stability. it can. Furthermore, since one of the intake valves can be switched from the rest state to the low speed opening / closing state, the intake air can be changed gently near this switching point, and a smooth engine output characteristic can be easily obtained.

[0120] Further, according to the variable valve timing mechanism with an engine of the present invention described in claim 3, the rocker arm of the second rocker arm and the third are both rotatably mounted to said rocker shaft, The first mode switching means is formed on the rocker shaft, has a first piston chamber having an opening exposed on the outer peripheral surface of the rocker shaft, and the second rocker arm is formed on the side of the second rocker arm. And a first recess that is aligned with the opening of the first piston chamber when the relative phase between the rocker shaft and the rocker shaft is in a predetermined state, and a direction that is orthogonal to the axis of the rocker shaft in the first piston chamber. And a projecting position in which one end of the rocker shaft is inserted into the first recess and the one end of the rocker shaft is projecting from the outer peripheral surface of the rocker shaft. And a second drive mechanism for driving the first piston between the projecting position and the retracted position. Second mode changing means is formed in the rocker shaft and has an opening exposed on the outer peripheral surface of the rocker shaft, and the third rocker arm and the rocker shaft are formed on the side of the third rocker arm. And a second recess that is aligned with the opening of the second piston chamber when the relative phase between the second piston chamber and the second piston chamber is in a predetermined state, and the second recess can move in a direction orthogonal to the axis of the rocker shaft. And a storage position in which one end of the rocker shaft is protruded from the outer peripheral surface of the rocker shaft and is fitted into the second recess and a storage position of which the one end is not projected from the outer peripheral surface of the rocker shaft. 2 fixers When, by being configured to include a second drive mechanism for driving between the second piston projecting position and the retracted position, the above-mentioned 3
It is possible to reliably switch between the two stages and to achieve efficient combustion in a wide rotation range.

[0121] Further, according to the variable valve timing mechanism with an engine of the present invention described in claim 4, said first drive mechanism, to urge the first piston to the retracted position side or the protruding position side A first urging means, a first oil chamber formed to drive the first piston against the first urging means toward the projecting position side or the retracted position side, and the engine Is provided with a first hydraulic pressure supply means capable of supplying a required hydraulic pressure into the first oil chamber when the rotational speed is the required rotation state, and the second drive mechanism includes the second piston. Second urging means for urging the second piston toward the storage position side or the protruding position side and the second piston against the second urging means toward the protruding position side or the stored position side. The second formed to
Oil chamber and the second when the engine is in the required rotation state.
And a second hydraulic pressure supply means capable of supplying a required hydraulic pressure into the oil chamber, so that the hydraulic pressure can be supplied while using, for example, an engine-driven hydraulic pump, and the variable valve described above is used. The timing mechanism can be easily realized.

According to the fifth aspect of the engine with a variable valve timing mechanism of the present invention, the first urging means and the second urging means include the first piston and the second urging means. All the pistons are urged toward the retracted position,
Is set so as to supply a required hydraulic pressure into the first oil chamber when the engine is in a medium speed or high speed rotation state, and the second hydraulic pressure supplying means controls With the configuration in which the required oil pressure is supplied to the second oil chamber in the high speed rotation state, for example, when the oil pressure is supplied by using the engine-driven hydraulic pump, when the engine is started, It is possible to realize a mode in which only one intake valve is operated. As a result, the cranking force of the starter is sufficient to correspond to the valve spring force of only one valve, and there is an advantage that the starter can be downsized. Further, there is an advantage that the manufacturing cost can be reduced by sharing the two parts of the hydraulic piston mechanism.

According to the engine with variable valve timing mechanism of the present invention as defined in claim 6, an engine pump in which both the first hydraulic pressure supply means and the second hydraulic pressure supply means are driven by the engine. The variable valve timing mechanism can be easily realized by the configuration in which the hydraulic pressure source is used. Further, according to the engine with a variable valve timing mechanism of the present invention as set forth in claim 7 , the control means determines whether the rotational speed range of the engine is in a low speed range, a medium speed range or a high speed range. The first mode switching means and the second mode switching means are set so as to control the states of the first mode switching means and the second mode switching means, and when the engine is in the low rotation speed range. Through the mode switching means, the second rocker arm is set to a non-coupling mode in which it is not linked to the first rocker arm, and the third rocker arm is set to a non-coupling mode in which it is not linked to the first and second rocker arms. Then, the first intake valve is closed and the second intake valve is opened / closed in accordance with the cam profile of the low speed cam to set a 1-valve low speed operating state, and the engine is in the medium speed range. To Through the first mode switching means and the second mode switching means,
By setting the second rocker arm in a linkage mode in which the first rocker arm and the first rocker arm are linked to each other, and setting the third rocker arm in a non-linkage mode in which the third rocker arm is not linked to the first and second rocker arms, Intake valve and the second
Both of the intake valves are opened and closed in correspondence with the cam profile of the low speed cam to operate at a low speed of two valves, and when the engine is in a high rotational speed range, the first mode switching means and the second mode switching The second rocker arm is linked to the first rocker arm by a means, and the third rocker arm is linked to the first and second rocker arms. With a configuration in which both the first intake valve and the second intake valve are set to be in a two-valve high speed operation state in which they are opened and closed in accordance with the cam profile of the high speed cam,
Achieves efficient combustion in a wide engine rotation range,
In particular, when the engine runs at low speeds, it is possible to realize a significant saving in fuel consumption due to lean combustion, and it is possible to obtain sufficient output in the mid-high speed rotation range.

According to the eighth aspect of the engine with a variable valve timing mechanism of the present invention, both the first intake valve and the second intake valve are provided on the downstream side of the intake passage of the engine. Fuel injection means for injecting fuel toward the second intake valve, and fuel injection guide means for deflecting the fuel injected from the injection hole of the fuel injection means toward the second intake valve side; The fuel injection guide switching means is provided to operate the fuel injection guide means when the valve is open and to stop the fuel injection guide means when the first intake valve is open. Has an advantage that fuel is not injected, combustion fluctuation due to fuel accumulation on the pause valve side is prevented, normal combustion is secured, and deterioration of exhaust gas is prevented.

Further, according to the engine with a variable valve timing mechanism of the present invention as defined in claim 9, in the intake passage,
Downstream of the intake bypass passage is provided with an idle rotation speed adjusting means provided with an intake bypass passage provided from an upstream portion to a downstream portion of the intake passage and an opening / closing valve for opening and closing the intake bypass passage. An end portion is connected to the fuel injection guide means, and the fuel injection guide means injects the intake air guided by the intake bypass passage in a required direction to thereby inject fuel injected from the injection hole into the second intake valve. With the configuration in which the fuel injection guide switching unit is configured to be deflected to the side and the on-off valve is used as the fuel injection guide switching unit, there is an advantage that the fuel pool can be prevented at low cost.

According to the engine with a variable valve timing mechanism of the present invention as defined in claim 10 , the third rocker arm is interposed between the first rocker arm and the second rocker arm. According to the configuration, there is an advantage that the valve can be driven accurately and appropriately.

[Brief description of drawings]

FIG. 1 is a perspective view of a valve train of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 2 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 3 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 5 is a sectional view of an essential part of an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 6 is a view showing an air injection port member provided in an intake passage portion of an engine with a variable valve timing mechanism as a first embodiment of the present invention, where (A) is (B) and FIG.
3 is a view as viewed from an arrow A in FIG.

FIG. 7 is a view showing a modified example of the air injection member of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 8 is a diagram showing output characteristics of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 9 is a diagram showing a valve lift state of an engine with a variable valve timing mechanism as a first embodiment of the present invention.

FIG. 10 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 11 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 12 is a diagram showing an operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the first embodiment of the present invention.

FIG. 13 is a sectional view showing a variable valve timing mechanism of an engine with a variable valve timing mechanism as a second embodiment of the present invention.

FIG. 14 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 15 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 16 is a diagram showing the operation of the variable valve timing mechanism of the engine with the variable valve timing mechanism as the second embodiment of the present invention.

FIG. 17 is a diagram showing a cam profile of a conventional engine with a variable valve timing mechanism.

FIG. 18 is a diagram showing output characteristics of a conventional engine with a variable valve timing mechanism.

FIG. 19 is a cross-sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

FIG. 20 is a side view showing a cam of a valve train of an engine with a variable valve timing mechanism of another conventional example.

FIG. 21 is a diagram showing output characteristics and hydraulic control characteristics of a valve operating system of a conventional engine with a variable valve timing mechanism.

FIG. 22 is a cross-sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

FIG. 23 is a sectional view showing a valve train of another conventional engine with a variable valve timing mechanism.

[Explanation of reference numerals] 1A bearing part 1C injector mounting part 2 second intake valve 3 first intake valve 3A valve stem 4 valve springs 5A, 5B spring retainer 6 first rocker arm (main rocker arm) 6A swinging end part 6B Screw mounting part 6C Contact surface 10 Base circular cam (base circle) 11 Cam shaft 12 Low speed cam 13 High speed cam 14 Second rocker arm (main rocker arm) 14A Swing end 14B Screw mounting part 14C Cylindrical base 15 Third rocker arm (sub rocker arm) 15A Swing end portion 15B Cylindrical base portion 15C Lever portion 16 Rocker shaft 16A, 16B Oil passage 17 Hydraulic piston mechanism as second mode switching means 17A Piston 17B Spring 17C Recess 17D Oil hole 17E Lid member 17F Piston chamber 17G Oil chamber 17H Collar portion 17I Stepped portion 18 Low speed roller 18A Shaft 18B Roller bearing 19 High speed roller 19A Shaft 19B Roller bearing 20 Arm spring mechanism 20A Outer case 20B Inner case 20C Spring 20D Abutting portion 21,22 Adjust Screws 21A, 22A Adjustment nut 27 Hydraulic piston mechanism as first mode switching means 27A Piston 27B Spring 27C Recess 27D Oil hole 27E Lid member 27F Piston chamber 27G Oil chamber 27H Collar 27I Stepped portion 37 Hydraulic piston mechanism 37A Piston 37B Spring 37C Recess 37D Oil Hole 37E Spring Retainer 37F Piston Chamber 37G Oil Chamber 40 Intake System 41 Air Cleaner 42 Intake Passage 43 Throttle Valve 44 Intake Manifold 44A, 44B Intake port 45 Combustion chamber 46 Injector (fuel injection means) 46A Injector tip portion 46B Fuel injection hole 47 Idle rotation speed adjusting means (ISC) 47A Open / close valve as fuel injection guide switching means 47B Solenoid 48A Intake bypass passage 48B Upstream side opening 48C Downstream side opening 49 Injector guide as fuel injection guide means 49A Pipe part 49C Base part 49B Air flow path 49D Air injection port 49E Arc-shaped slit as air injection port 50 Electronic control unit as control means (ECU) 51 Hydraulic oil supply system 52 Hydraulic pump (engine pump) 53 Pressure adjusting means 54 Switching valve

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masahiko Kubo 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Noriyuki Miyamura 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Automobile Industry Co., Ltd. (72) Inventor Hiroshi Kamata 5-3-8, Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Industry Co., Ltd.

Claims (9)

[Claims] 1. A low-speed cam which has two intake valves, a first intake valve and a second intake valve, and a cam profile for low-speed valve timing, and which rotates in response to rotation of a crankshaft of an engine. A cam profile for high speed valve timing including a cam profile for low speed valve timing, and a high speed cam that rotates in response to rotation of the crankshaft, and is pivotally supported at a required portion of the engine. The rocker shaft does not directly contact the low speed cam and the high speed cam,
A first rocker arm that is provided so as to rotate around the rocker shaft and that abuts against the first intake valve to open / close the first intake valve; A second rocker arm that includes a roller and can swing in response to the cam profile of the low speed cam and that opens and closes the second intake valve by abutting against the second intake valve; A third rocker arm that has a high-speed roller that abuts on the cam and swings corresponding to the cam profile of the high-speed cam, and a second rocker arm that is not linked to the first rocker arm are linked to a non-coupling mode. Switching between a first mode switching means capable of switching between a linked mode and a linked mode in which the third rocker arm is linked to a non-linked mode in which the first and second rocker arms are not linked to each other. And a control means for controlling the states of the first mode switching means and the second mode switching means according to the rotational state of the engine. , Engine with variable valve timing mechanism. 2. The second rocker arm and the third rocker arm are both rotatably mounted on the rocker shaft, and the first mode switching means is formed on the rocker shaft. A first piston chamber having an opening exposed on the outer peripheral surface of the shaft, and a first rocker arm formed on the side of the second rocker arm, and the first phase when the relative phase between the second rocker arm and the rocker shaft is in a predetermined state. A first recess aligned with the opening of the piston chamber, and is inserted into the first piston chamber so as to be movable in a direction orthogonal to the axis of the rocker shaft, one end of which is inserted into the rocker shaft. A first piston capable of having a projecting position projecting from the outer peripheral surface and fitted into the first recess and a storage position in which the one end does not project from the outer peripheral surface of the rocker shaft; and the first piston. The second mode switching means is formed on the rocker shaft and is exposed on the outer peripheral surface of the rocker shaft, the first mode driving mechanism being configured to have a first drive mechanism for driving between a protruding position and the retracted position. A second piston chamber having an opening formed therein, and an opening of the second piston chamber formed on the side of the third rocker arm when the relative phase between the third rocker arm and the rocker shaft is in a predetermined state. A second recess that is aligned with the second recess is inserted into the second piston chamber so as to be movable in a direction orthogonal to the axis of the rocker shaft, and one end of the recess is projected from the outer peripheral surface of the rocker shaft. A second piston capable of having a protruding position fitted in the second recess and a retracted position in which the one end does not protrude from the outer peripheral surface of the rocker shaft; and the second piston having the protruding position and the retracted position. Between positions The engine with a variable valve timing mechanism according to claim 1, wherein the engine is provided with a second drive mechanism for driving. 3. A first urging means for urging the first drive mechanism to urge the first piston toward the storage position side or the protruding position side, and the first piston to move the first piston to the first position. A first oil chamber formed so as to be hydraulically driven to the protruding position side or the storage position side against the biasing means; and in the first oil chamber when the engine is in a required rotation state. A first hydraulic pressure supply means capable of supplying a required hydraulic pressure, and the second drive mechanism urges the second piston toward the storage position side or the protruding position side. Two biasing means, a second oil chamber formed to hydraulically drive the second piston to the projecting position side or the storage position side against the second biasing means, A second hydraulic pressure supply means capable of supplying a required hydraulic pressure into the second oil chamber when the engine is in a required rotation state. Characterized in that it is made, the variable valve timing mechanism with an engine according to claim 2, wherein. 4. The first urging means and the second urging means urge both the first piston and the second piston toward the storage position side, and the first hydraulic pressure. The supply means is set so as to supply a required hydraulic pressure into the first oil chamber when the engine is in a medium speed and high speed rotation state, and the second hydraulic pressure supply means causes the engine to rotate at a high speed. The engine with variable valve timing mechanism according to claim 3, wherein the engine is set so as to supply a required hydraulic pressure into the second oil chamber when in the state. 5. The variable valve according to claim 4, wherein both the first hydraulic pressure supply means and the second hydraulic pressure supply means use an engine pump driven by the engine as a hydraulic pressure source. Engine with timing mechanism. 6. The first mode switching means and the second mode depending on whether the rotation speed range of the engine is in a low speed range, a medium speed range, or a high speed range. When the engine is set to control the state of the switching means and the engine is in the low rotation speed range, the second rocker arm is moved to the first rocker arm through the first mode switching means and the second mode switching means. By setting the non-coupling mode in which the rocker arm is not linked to the third rocker arm and setting the non-coupling mode in which the third rocker arm is not linked to the first and second rocker arms, the first intake valve is closed and the second intake valve is closed. The one-valve low-speed operating state in which the intake valve of the engine is opened / closed corresponding to the cam profile of the low-speed cam, and when the engine is in the medium-speed rotation range, the first mode switching means and the second mode switching Through means By setting the second rocker arm in a linkage mode in which the first rocker arm and the first rocker arm are linked to each other, and setting the third rocker arm in a non-linkage mode in which the third rocker arm is not linked to the first and second rocker arms, Both the second intake valve and the second intake valve are opened and closed in correspondence with the cam profile of the low speed cam, and a two-valve low speed operation state is set, and when the engine is in the high speed rotation speed range, the first mode switching means. And a linking mode for linking the second rocker arm to the first rocker arm through the second mode switching means, and a linking mode for linking the third rocker arm to the first and second rocker arms. By doing so, the first intake valve and the second intake valve are both set to a two-valve high-speed operating state in which they are opened and closed in accordance with the cam profile of the high-speed cam. Characterized in that it is configured to, according to claim 1 variable valve timing mechanism with the engine according. 7. A fuel injection means for injecting fuel toward both sides of the first intake valve and the second intake valve is provided in a downstream portion of an intake passage of the engine, the fuel injection means. Fuel injection guide means for deflecting the fuel injected from the injection hole of the first intake valve to the side of the second intake valve, and the fuel injection guide means for operating the first intake valve when the first intake valve is closed. 7. An engine with a variable valve timing mechanism according to claim 6, further comprising fuel injection guide switching means for stopping the fuel injection guide means when the valve is operated. 8. An idle rotation speed adjusting means comprising an intake bypass passage provided in the intake passage from an upstream portion to a downstream portion of the intake passage, and an opening / closing valve for opening and closing the intake bypass passage. Attached, the downstream end of the intake bypass passage is connected to the fuel injection guide means, and the fuel injection guide means injects the intake air guided in the intake bypass passage in a desired direction to thereby inject the injection hole. 8. The variable valve timing according to claim 7, wherein the injection fuel from the fuel injection system is configured to be deflected to the side of the second intake valve, and the on-off valve is used as the fuel injection guide switching means. Engine with mechanism. 9. The engine with variable valve timing mechanism according to claim 1, wherein the third rocker arm is provided between the first rocker arm and the second rocker arm.