JP2519619B2 - Internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine, and more particularly to an internal combustion engine capable of intake according to the operating condition of the engine.

[0002]

2. Description of the Related Art Conventionally, by changing the volume of the intake system according to the engine speed, the natural frequency of the intake system is changed so that the charging efficiency corresponds to the engine speed and the fuel consumption in the low speed range is reduced. An internal combustion engine has been realized which is designed to reduce noise and improve output in a high speed range.

[0003]

By the way, a valve operating characteristic changing mechanism for obtaining an output and fuel consumption adapted to the engine operating state by changing the operating characteristic of the intake valve in accordance with the operating state of the engine, and an intake valve An internal combustion engine having both a passage configuration changing mechanism capable of changing the configuration of the passage in accordance with the engine speed is already known (for example, the actual construction number 59-16).
No. 0824), and in such a case,
Output characteristics are obtained by combining changes in the intake valve operating characteristics and changes in the intake passage configuration.

However, in the above-mentioned known device, only one is provided in the middle portion of the high speed intake passage in order to switch the configuration of the intake passage.
Since the individual opening / closing valves are provided to simply control the opening / closing of the intermediate portion of the passage, it is difficult to switch the configuration of the intake passage in various ways. A dead space is formed in the passage from the on-off valve to the downstream end, which causes unstable intake during low-speed rotation (hence, idle instability) and reduced acceleration response from low-speed rotation.

The present invention has been made in view of the above circumstances, and is based on a combination of a change in the intake valve operating characteristic and various changes in the intake passage configuration while avoiding the problem at the time of low speed rotation. It is an object of the present invention to provide an internal combustion engine capable of obtaining excellent output characteristics.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, an intake valve for opening and closing an intake valve opening has an opening / closing operation characteristic of the intake valve. A valve mechanism that can be changed in accordance with the above is linked and connected, and an intake passage is communicated with an intake port provided in the engine body in series with the intake valve opening, and one end of the additional intake volume is connected to the upstream portion of this intake passage. but also that the downstream portion communicates with the other end of the additional suction volume, respectively, the one end and the other end of the additional intake volume, closing valve of a pair that will be closing control in accordance with the engine speed Each is arranged , each opening and closing
Engine speed that switches the valve opening / closing mode and opening / closing of the valve mechanism
The engine speed for changing the operating characteristic is set to be different from each other .

According to a second feature of the present invention, in addition to the structure of the first feature, the pair of on-off valves is reduced in number.
Both are kept closed when the engine speed is below the specified speed.
Be held .

[0008]

[Operation] According to the first feature described above, based on the opening / closing control of the pair of on-off valves located at one end and the other end of the additional intake volume, the additional intake volume is changed in position and the high-speed intake path is used. like the use of it is possible, since the intake passage arrangement can be changed to various switching manner, a change of such intake passage structure embodiment, the valve operating characteristic changing and various combination of the intake valve by the valve mechanism Can
Therefore, various changes can be given to the output characteristics of the engine. Moreover, the engine speed that switches the open / close mode of each on-off valve
And the engine speed that changes the opening / closing operation characteristics of the valve train.
Since they are set differently from each other, changes in the intake passage configuration
And combination of the change in intake valve valve operating characteristics
Not only can it be realized, but the switching
Can be reduced as much as possible.

Further , according to the second feature, the pair of on-off valves are both kept closed at least when the engine speed is equal to or lower than the predetermined speed, so that the bypass between the upper and downstream portions of the intake passage is bypassed. Due to the special provision of the additional intake volume described above, it is effective to cause inconvenience such that it becomes a dead space with respect to the intake passage in the low speed operation region of the engine to make the intake air unstable or reduce the acceleration responsiveness. Avoided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. First, referring to FIG.
This internal combustion engine is a multi-cylinder internal combustion engine. In order to open and close a pair of intake valve openings 1 provided in the engine body E corresponding to each cylinder, an intake valve 2 of each cylinder pair is provided in the engine body E.
The intake valves 2 are opened and closed by the valve operating mechanism 3. Further, an intake port 4 for each cylinder is bored in the engine body E so as to be commonly connected to the pair of intake valve ports 1. Each intake port 4 is provided in an intake box 5 common to each cylinder. Connected via 6. The intake box 5 is further connected to an air cleaner (not shown) via a throttle body (not shown).

The intake box 5 forms a long intake chamber 7 along the cylinder arrangement direction of the engine main body E. The intake box 5 has a pair of first cylinders for communicating with the intake manifold 6. The first outlet 8 and the second outlet 9 are provided adjacent to each other.

The intake manifold 6 comprises a first connecting member 10, a passage forming member 11 and a second connecting member 12 which are connected in this order from the upstream end side, that is, the intake box 5 side. The first connecting member 10 is coupled to the intake box 5, and the first connecting member 10 includes a passage portion 13 that communicates with the first outlet 8 of the intake casing 5 and a passage portion 14 that communicates with the second outlet 9. Are provided adjacent to each other. Further, the passage forming member 11 has a passage portion 15 communicating with the passage portion 13 and a passage portion 1
4 and a passage portion 16 leading to 4 are provided over a relatively long distance adjacent to each other. Further, the second connecting member 12 is connected to the intake port 4 of the engine body E, and the second connecting member 12 includes a passage portion 17 that communicates between the intake port 4 and the passage portion 15, and the passage portion 17. 1
Branch passage portion 1 connecting the intermediate portion of 7 and the passage portion 16
And 8 are provided.

By connecting the branch box 5 and the intake port 4 via the intake manifold 6, a main intake passage 19 from the first outlet 8 to the intake port 4 via the passage portions 13, 15, 17 is formed. The length and cross-sectional area of the main intake passage 19 are, as shown in FIG. 2, in the first rotation range A1 defined on the low speed side of the engine rotation range, for example, in the low / medium rotation range of a constant rotation speed N4 or less. It is set to obtain the optimum intake inertia effect. Further, an auxiliary intake passage 20 is formed which is connected to the downstream end of the first intake passage 19 from the second outlet 9 through the passage portions 14 and 16 and the branch passage portion 18, and the length and crossing of the auxiliary intake passage 20 are formed. When the area is combined with the first intake passage 19, the optimum intake inertia effect can be obtained in the second rotation range A2 defined on the high speed side of the rotation range of the engine, for example, in the high speed rotation range exceeding the rotation speed N4. Is set as follows.

The main intake passage 19 constitutes the intake passage of the present invention. The downstream end of the auxiliary intake passage 20 is directly connected to the downstream portion of the main intake passage 19 and the upstream end thereof is connected through the intake chamber 7, and the main intake passage 19 (that is, the present invention). An additional intake volume of the present invention is formed by connecting one end and the other end to the upstream part and the other end of the intake passage).

The upstream end of the second intake passage 20, that is, the first
A butterfly type on-off valve 21 that is driven to open and close by an actuator 23 is disposed in the passage portion 14 of the connecting member 10, and a downstream end portion of the second intake passage 20, that is, a branch passage portion 18 of the second connecting member 12, Butterfly type on-off valve 22 which is opened and closed by an actuator 24
Is arranged. Moreover, the on-off valve 22 is configured so that the volume of the hatched portion indicated by the chain line is as small as possible in order to avoid disturbance of the intake flow between the passage portion 19 of the first intake passage 19 and the intake port 4 when it is fully closed. When the valve is opened, it is arranged so as to avoid obstructing the intake air flow in the first and second intake passages 19 and 20. Further, the second connection member 12 is provided with a fuel injection valve 26 for injecting fuel toward the intake port 4.

By the way, the on-off valve 21 is closed and the on-off valve 2 is closed.
2 is opened, the opening / closing valve 21 of the auxiliary intake passage 20 is opened.
Downstream (ie, branch passage portion 18 and passage portion 1
6) is added to the main intake passage 19 as an additional intake volume. On the other hand, when the opening / closing valve 21 is opened and the opening / closing valve 22 is closed, the opening / closing valve 2 of the auxiliary intake passage 20 is opened.
The upstream side of 2 (that is, the passage portions 14 and 16) is added to the main intake passage 19 as an additional intake volume.

The actuators 23, 24 are individually controlled by a control means 25 such as a computer. The control means 25 controls the actuators 23, 24 in accordance with the engine speed detected by the engine speed detector 27. The operation of 24 is controlled individually, so that the on-off valves 21 and 22 are individually opened and closed. That is, the on-off valve 21 is shown in FIG.
As shown by, the valve is opened when the engine speed is relatively low, that is, when the engine speed N1 is lower than the engine speed N4, and the engine speed is higher than the engine speed N1 and is higher than the engine speed N.
When the rotation speed N3 lower than 4 is exceeded, the valve is closed, and when the rotation speed N4 is exceeded, the valve is opened. The open / close valve 22 opens when the rotation speed N3 is exceeded.

Referring also to FIGS. 3, 4 and 5,
A valve mechanism 3 for opening and closing the pair of intake valves 2 is provided integrally with a cam shaft 28 that is rotationally driven from a crankshaft (not shown) of the engine at a speed reduction ratio of 1/2, and the cam shaft 28. A pair of low-speed cams 29, 29 and a high-speed cam 30, a rocker shaft 31 fixed to the engine body E in parallel with the cam shaft 28, and first, second, and third shafts pivotally supported by the rocker shaft 31. Camshaft 2 including third rocker arms 32, 33, 34 and valve operation changing means 35 provided between the rocker arms 32 to 34.
8 is rotatably arranged above the engine body E,
The low speed cams 29, 29 are integrated with the cam shaft 28 at positions corresponding to the intake valves 2, 2, and the high speed cam 30 is integrated with the cam shaft 28 between the low speed cams 29, 29. The low speed cam 29 is a valve operating valve corresponding to a third rotation range A3 (see FIG. 2) which is set at a low speed side in the rotation range of the engine by making the engine rotation speed range different from the first rotation range A1. This is for obtaining the characteristic, that is, the low speed operation characteristic, and the third rotation range A3 is set to be equal to or lower than the second rotation speed N2 which is larger than the first rotation speed N1 and smaller than the third rotation speed N3. Further, the high-speed cam 30 operates at a speed higher than the third rotation range A3 and corresponds to a fourth rotation range A4 (see FIG. 2) which is set by making the engine rotation speed range different from the second rotation range A2. This is for obtaining the valve characteristic, that is, the medium / high speed operation characteristic, and the fourth rotation range A4 is set to a rotation speed range exceeding the second rotation speed N2. The low speed cam 29 is used for the camshaft 2
Higher portion 29a having a relatively small protrusion amount along the radial direction of 8
And a high-speed cam 30 having a constant radius base circle portion 29b, a high-level portion 30a in which the protrusion amount and center angle range along the radial direction of the camshaft 28 are larger than the high-level portion 29a, and a constant radius. And a base circle portion 30b.

The rocker shaft 31 has one intake valve 2
The first rocker arm 32 that is interlocked with and connected to the third rocker arm 32 that is interlocked and connected to the other intake valve 2 and the second rocker arm 33 that is disposed between the first and third rocker arms 32 and 34 are mutually connected. Is pivoted adjacent to. Also, one of the low speed cams 2 is provided above the first rocker arm 32.
9 is provided with a cam slipper 36, a second rocker arm 33 is provided with a cam slipper 38 which is brought into sliding contact with the high speed cam 30, and a third rocker arm 34 is brought into sliding contact with the other low speed cam 29 above the third rocker arm 34. A cam slipper 37 is provided.

Collar portions 39 are provided above the intake valves 2, respectively, and valve springs 40 are provided between the collar portions 39 and the engine body E. The valve spring 40 urges the valve in the valve closing direction, that is, upward. Further, tappet screws 41 capable of contacting the upper ends of the intake valves 2 are respectively screwed to the tip ends of the first and third rocker arms 32, 34 so as to be able to move forward and backward.

The second rocker arm 33 is elastically urged in a direction of sliding contact with the high speed cam 30 by elastic urging means 42 provided between the second rocker arm 33 and the engine body E. This bullet urging means 42
Is equipped with a bottomed cylindrical lifter 43 whose closed end is in contact with the second rocker arm 33, and a lifter spring 44 interposed between the lifter 43 and the engine body E. It is slidably fitted in the provided bottomed hole 45.

The valve operation changing means 35 is a first switching pin 51 that can connect the third and second rocker arms 34 and 33.
, A second switching pin 52 that can connect the second and first rocker arms 33, 32, and a first and second switching pin 5
A third switching pin 53 for restricting the movement of 1, 52 and a return spring 54 for urging the respective switching pins 51-53 toward the connection release side are provided.

In the third rocker arm 34, a bottomed guide hole 55 parallel to the rocker shaft 31 has a second open end.
The first switching pin 51 is slidably fitted in the guide hole 55, and the hydraulic chamber 56 is provided between the first switching pin 51 and the closed end of the guide hole 55. Is defined. Moreover, a regulation step portion 57 is provided on the inner surface of the intermediate portion of the guide hole 55 so as to face the open end side, and when the one end of the first switching pin 51 abuts against the regulation step portion 57, the other end surface thereof is the third. And has an axial length such that it is located between the second rocker arms 34, 33. Further, a communication passage 58 communicating with the hydraulic chamber 56 is bored in the third rocker arm 34, and a hydraulic pressure supply passage 59 is bored in the rocker shaft 31. Further, the communication passage 58 and the hydraulic pressure supply passage 59 are
Through the communication hole 60 formed in the side wall of the rocker shaft 31, the third rocker arm 34 is always communicated regardless of the rocking state.

In the second rocker arm 33, a guide hole 61 of the same diameter corresponding to the guide hole 55 is bored in parallel with the rocker shaft 31 between both side surfaces thereof, and the guide hole 61 has a second switching pin 52. Are slidably fitted.

In the first rocker arm 32, a bottomed guide hole 62 having the same diameter corresponding to the guide hole 61 is bored in parallel with the rocker shaft 31 and the open end is on the second rocker arm 33 side. 62 to the third switching pin 53
Are slidably fitted. Moreover, the shaft portion 63 coaxially connected to the third switching pin 53 is movably inserted into the guide hole 64 formed at the closed end of the guide hole 62. Return spring 5
4 is provided between the closed end of the guide hole 62 and the third switching pin 53 so as to surround the shaft portion 63 coaxially, and the return spring 5
The switching pins 51 to 53 that are in contact with each other by 4 are urged toward the disconnection side, that is, the hydraulic chamber 56 side.

When the hydraulic pressure supplied to the hydraulic chamber 56 is released, the respective switching pins 51 to 53 are moved to the connection release side by the spring force of the return spring 54. In this state, the first and second switching pins 51 are released. The abutment surfaces of 52 are the third and the second.
It is between the rocker arms 34 and 33, the contact surfaces of the second and third switching pins 52 and 53 are between the second and first rocker arms 33 and 32, and the rocker arms 32 to 34 are not connected and operate at low speed. It becomes a state. Therefore, the intake valves 2 and 2 are opened and closed at the timing and lift amount corresponding to the shape of the low speed cams 29 and 29, that is, the third rotation range A3.

When the hydraulic pressure is supplied to the hydraulic chamber 56, each of the switching pins 51 to 53 moves in the direction away from the hydraulic chamber 56 against the spring force of the return spring 54, and the first switching pin 51.
Is fitted in the guide hole 61, and the second switching pin 52 is fitted in the guide hole 62 to connect the rocker arms 32 to 34 to each other, which results in a medium / high speed operation mode. Therefore, the intake valves 2 and 2 have the same shape as the high-speed cam 30, that is, the fourth rotation range A.
It opens and closes at the timing and lift amount corresponding to 4.

Referring again to FIG. 1, an oil passage 67 communicating with the hydraulic pressure supply passage 59 in the rocker shaft 31, an oil supply passage 69 communicating with a hydraulic pressure supply source 68 such as a hydraulic pump, and an oil tank 70.
A control valve 66 that is switched between by the excitation and demagnetization of the solenoid 65 is provided between the return oil passage 71 and the return oil passage 71. The solenoid 65 of the control valve 66 controls the control means 25.
The excitation and demagnetization state can be switched by
In the third rotation range A3 where the engine speed is equal to or lower than the second speed N2, the solenoid 65 is demagnetized, the valve mechanism 3 is in the low speed operation mode, and the engine speed exceeds the second speed N2. In the four rotation range A4, the solenoid 65 is excited, and the valve mechanism 3 is in the medium / high speed operation mode.

Next, the operation of this embodiment will be described with reference to FIG. 2. In the low speed rotation range below the first rotation speed N1, both the on-off valves 21 and 22 are closed and the auxiliary intake passage 20 is shut off. Therefore, the valve mechanism 3 is in a low speed operation mode, and the output torque at this time is a curve a indicated by a broken line.
That is, since the length and the cross-sectional area of the main intake passage 19 are set so as to obtain the optimum intake inertia effect in the relatively low first rotation range A1, it is possible to obtain a high torque. Moreover, the opening / closing valve 2 at the downstream end of the auxiliary intake passage 20
Since 2 is closed, the dead space generated at the downstream end of the auxiliary intake passage 20 can be minimized, and the stability of idle rotation can be ensured, and
It is possible to improve the responsiveness when suddenly accelerating from around the idle speed.

Further, the second rotation speed N is exceeded by exceeding the first rotation speed N1.
In the rotation range of 2 or less, the valve mechanism 3 is in the low speed operation mode, and the opening / closing valve 21 at the upstream end of the auxiliary intake passage 20 is
Is opened, and the open / close valve 22 at the downstream end remains closed. In this rotation range, since the passage portions 14 and 16 are added to the intake chamber 7 as the additional intake volume, the natural vibration in the main intake passage 19 changes, and the torque peak is displaced like the curve b1 indicated by the broken line. You can

In the rotation range of the second rotation speed N2 and the third rotation speed N3 or less, the valve mechanism 3 changes from the low speed operation mode to the medium / high speed operation mode, so that the torque peak has a curve b2 indicated by a broken line. It shifts as shown in.

Further, in the rotation range of the third rotation speed N3 and the fourth rotation speed N4 or less, the valve mechanism 3 remains in the medium / high speed operation mode, whereas the upstream end portion of the auxiliary intake passage 20 The on-off valve 21 closes and the on-off valve 22 at the downstream end opens. Thereby, the branch passage portion 18 and the passage portion 1
6 is added to the main intake passage 19 as an additional intake volume, the natural frequency of the main intake passage 19 changes, and the torque peak deviates as indicated by a broken line b3. Moreover, in the case of a multi-cylinder internal combustion engine, it is possible to shift the rotational speed that causes intake interference.

In the rotation range exceeding the fourth rotation speed N4, both on-off valves 21 and 22 are opened, and the auxiliary intake passage 20 is in a communication state. The equivalent pipe length and the cross-sectional area of the sub intake passage 20 and the main intake passage 19 are set so that the optimum intake inertia effect can be obtained in the fourth rotation range A4, and therefore, as indicated by a curve c indicated by a broken line. It is possible to obtain a high output.

In this way, in the entire engine speed range,
It is possible to obtain five torque peaks indicated by a, b1, b2, b3 and c, and it is possible to obtain an output torque in which those torque peaks are connected like a curve indicated by a solid line, and high output in a wide range. Can be obtained.

FIG. 6 shows another embodiment of the present invention in which both the on-off valves 21 and 22 are opened when the engine speed exceeds the fourth speed N4. Even when the valve operating mechanism 3 is changed from the low speed operation mode to the medium / high speed operation mode when the rotation speed exceeds the second rotation speed N2, three torque peaks can be generated, and each torque peak can be generated. High power can be obtained in a wide range by connecting them. Since the on-off valve 22 is closed in the low speed rotation range,
The stability of the idle rotation and the response at the time of sudden acceleration can be ensured as in the above-mentioned embodiments.

[0036]

As described above, according to the first feature of the present invention, in the intake valve that opens and closes the intake valve opening, the opening / closing operation characteristic of the intake valve can be changed according to the engine speed. One end of the additional intake volume is connected to the upstream part of the intake passage, which is linked and connected to the intake valve port via the intake port, and the other end of the additional intake volume is connected to the downstream part thereof. Since a pair of open / close valves that are controlled to open / close according to the engine speed are provided at one end and the other end of the additional intake volume, the addition of the additional intake volume by simply opening / closing control of both open / close valves. The configuration of the intake passage can be changed to various switching modes such as the position change and the use as a high-speed intake passage. Therefore, the change of the intake passage configuration and the valve actuation of the intake valve by the valve mechanism are possible. multi-between the characteristic change By a combination, to be able to provide various changes in the output characteristics of the engine, excellent operating characteristics such as may output a high torque can be obtained over a wide operating range.
In addition, the engine speed that changes the opening / closing mode of each on-off valve
The engine speed, which changes the opening / closing operation characteristics of the valve mechanism,
Since it is set differently, the change of the intake passage configuration mode,
The combination with changes in the valve operating characteristics of the intake valve can be further diversified.
In addition to the switching shock
The intake can be reduced as much as possible and smoother intake control is possible.
It becomes Noh.

Further , according to the second aspect of the present invention, since the pair of on-off valves are both kept closed at least when the engine speed is equal to or lower than the predetermined speed, the upper and downstream portions of the intake passage. Due to the special provision of the above-mentioned additional intake volume that bypasses the space, it may cause inconvenience such that it becomes a dead space with respect to the intake passage in the low speed operation region of the engine, which makes the intake unstable or reduces the responsiveness of acceleration. It can be effectively avoided, and in combination with the effect of changing the valve operating characteristics of the intake valve by the valve mechanism, it greatly contributes to the improvement of the idle stability of the engine and the acceleration response from the low speed operation range. it is Ru can.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is an output torque characteristic diagram.

FIG. 3 is an enlarged view taken along the arrow III in FIG.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

5 is an enlarged cross-sectional view taken along line VV of FIG.

FIG. 6 is an output torque characteristic diagram of another embodiment of the present invention.

[Explanation of symbols]

 1 Intake valve port 2 Intake valve 3 Valve mechanism 4 Intake port 19 Main intake passage as an intake passage 20 Sub intake passages 21 and 22 as an additional intake volume

Claims (2)

(57) [Claims] 1. An intake valve (2) for opening and closing an intake valve opening (1)
Shows the opening / closing operation characteristics of the intake valve (2) at the engine speed (N
The valve mechanism (3) configured to be changeable according to 2) is interlocked and connected, and the intake passage is connected to the intake port (4) provided in the engine body (E) in series with the intake valve opening (1). (1
9) communicates with each other, one end of the additional intake volume (20) communicates with the upstream portion of the intake passage (19), and the other end of the additional intake volume (20) communicates with the downstream portion thereof. At one end and the other end of the intake volume (20), the engine speed (N1, N3, N4) a pair of open-close valve that will be closing control in accordance with the (21, 22) are disposed respectively, each Turn off the on / off valve (21, 22)
Engine speed to change (N1, N3, N4) and valve mechanism
With the engine speed (N2) that changes the opening / closing operation characteristic of (3)
The internal combustion engine is characterized in that the two are set differently from each other . 2. The pair of on-off valves (21, 22) are small in number.
Even if the engine speed is below the predetermined speed (N1)
The internal combustion engine according to claim 1, wherein the internal combustion engine is held in a closed state .