JPH11159311A - Adjuster for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine, which is operated in the condition that a compression ratio is set to be lower than an expansion ratio, capable of smoothly performing spark advance adjustment of an intake valve through a valve timing variable mechanism during cold start and favorably preventing the leakage of liquid from the valve timing variable mechanism during hot operation. SOLUTION: An adjuster for an internal combustion engine to forcibly rotate a crank shaft the reverse direction with a generator (served as a starter motor), when the engine is started, and adjust relative rotation between a housing 28 and a vane 31 constituting a valve timing changing mechanism (VVT) 11 to the side of spark advance is formed with the VVT 11, an oil control valve 16, an electronic controller 17 and others. The housing 28 and a cover 38 are formed of iron based sintered metal material and the vane 31 is formed of material with a greater thermal expansion coefficient than the iron based sintered metal material, such as aluminum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to an internal combustion engine such as an internal combustion engine mounted on a hybrid vehicle, which is operated with a compression ratio set lower than an expansion ratio. Also, the present invention relates to an apparatus for advancing an intake valve through a variable valve timing mechanism at the time of starting.

[0002]

2. Description of the Related Art In recent years, it has been desired to minimize the amount of exhaust gas emitted from an internal combustion engine mounted on a vehicle from the viewpoint of environmental protection such as carbon dioxide emission regulations. A hybrid vehicle capable of stopping an internal combustion engine in accordance with a running state of the vehicle and running by an electric motor has been proposed and has come into practical use. This hybrid vehicle has two types of prime movers, such as an internal combustion engine and an electric motor, and switches between the prime movers according to the running state. Such a type of hybrid vehicle is particularly called a parallel hybrid vehicle.

[0003] The design concept of the internal combustion engine mounted on this parallel hybrid vehicle is different from the design concept of an ordinary vehicle, and is focused on improving the thermal efficiency of the internal combustion engine. Therefore, the Atkinson cycle, which is a high expansion ratio cycle, is sometimes applied to an internal combustion engine of a parallel hybrid vehicle. The high expansion ratio cycle is a cycle having an expansion ratio higher than the compression ratio.For example, after setting the volume of the combustion chamber to be small, the closing timing of the intake valve in the compression stroke by the variable valve timing mechanism is set to a normal Otto. The compression ratio in the same stroke is reduced by, for example, greatly delaying the cycle.

As the variable valve timing mechanism, there is known a so-called vane type variable valve timing mechanism for controlling a relative rotation phase between a housing drivingly connected to a crankshaft and a vane connected to, for example, an intake camshaft by hydraulic pressure. Have been.

[0005]

Incidentally, in the internal combustion engine to which the above Atkinson cycle is applied, a smooth start may not be obtained unless a sufficient compression ratio is given to the air-fuel mixture at the time of the start. Therefore, as a method of giving a sufficient compression ratio to the air-fuel mixture at the time of starting, a method of making the valve stroke of the intake valve of the internal combustion engine earlier and extending the compression stroke is considered. As a means for changing the valve timing, a method of using the vane type variable valve timing mechanism is conceivable. That is, the electric motor (starter motor) connected to the crankshaft is rotated at the time of starting,
In this method, the intake camshaft (vane) is advanced relative to the crankshaft (housing) by utilizing the friction (friction) of the intake cam at that time.

[0006] However, this advanced starting is performed at a low temperature, especially-
If the temperature is to be increased in severe cold conditions such as 20 ° C., the sliding resistance between the housing and the vane increases because the viscosity of the lubricating oil existing between the housing and the vane increases, and the housing and the vane rotate integrally. Sometimes. That is, the sliding resistance between the housing and the vane is larger than the friction of the intake cam, and the relative movement of the vane with respect to the housing becomes difficult, so that the intake camshaft can be advanced with respect to the crankshaft. May not be possible.

[0007] In order to avoid such a situation,
A method of reducing the sliding resistance by setting a large clearance between the housing and the vane is also conceivable.However, according to this method, when the variable valve timing mechanism is operated during a warm period, the clearance between the housing and the vane is reduced. A new problem of oil leakage also arises.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine that is operated in a state where the compression ratio is set lower than the expansion ratio. The present invention provides an internal combustion engine adjustment device that can smoothly adjust the advance angle of an intake valve through a variable valve timing mechanism and that can appropriately prevent liquid leakage from the variable valve timing mechanism during a warm period. It is in.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, one and the other of a camshaft having the same rotational axis and driving the engine output shaft and the engine valve to open and close are provided. Liquid is provided on at least one side of the vane by providing a connected first and second rotator and defining a recess formed in the first rotator by a vane formed in the second rotator. A variable valve timing mechanism for forming a chamber and changing the relative rotation phase between the engine output shaft and the camshaft by relatively rotating the first and second rotating bodies based on hydraulic control of the formed liquid chamber; An electric motor capable of driving the engine output shaft to rotate from the outside, and at the time of starting the internal combustion engine, advancing the valve timing variable mechanism through forced rotation of the engine output shaft by the electric motor. An adjusting device, wherein each of the first and second rotating bodies constituting the variable valve timing mechanism has a relation that a material of the first rotating body has a coefficient of thermal expansion <the coefficient of thermal expansion of the second rotating body. The gist is that they have been selected to be satisfied.

With this configuration, when the internal combustion engine is started, the output shaft of the internal combustion engine is reversely rotated by the electric motor, and the intake valve is advanced relatively to the output shaft of the internal combustion engine.
At this time, a material having a thermal expansion coefficient larger than that of the material forming the first rotating body was selected as a material forming the second rotating body. In the above, a gap is formed between the first rotator and the second rotator to enable relative rotation between the first rotator and the second rotator. Further, based on the difference in the coefficient of thermal expansion, the gap is suitably narrowed in a warm state. Therefore, the advance angle adjustment can be performed smoothly even at a low temperature, and the first rotating body and the
From the gap with the rotating body, that is, from the variable valve timing mechanism.

Further, according to the second aspect of the present invention, the first aspect of the present invention is provided.
The gist of the above-mentioned control device for a vehicle-mounted internal combustion engine is that the first rotating body is formed of an iron-based material, and the second rotating body is formed of an aluminum-based material.

According to this configuration, the advance angle adjustment and the thermal expansion coefficient difference between the iron-based material and the aluminum-based material (the coefficient of linear expansion of aluminum is almost twice the coefficient of linear expansion of iron) are used. Liquid leakage can be easily and suitably prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the present invention is embodied in an adjusting device provided in a four-cylinder gasoline engine mounted on a hybrid vehicle will be described below with reference to FIGS.
This will be described with reference to FIG.

FIG. 1 is a sectional view showing an intake-side camshaft 12 provided with a vane-type variable valve timing mechanism (hereinafter, simply referred to as "VVT mechanism") 11, and the like. The journal 12 a of the intake side camshaft 12 is rotatably supported by an upper end surface of the cylinder head 18 and a bearing cap 19. As shown in FIG. 3, a plurality of sets (four sets in this embodiment) of cams 20 are formed on the outer peripheral portion of the base end side (the right side in FIG. 1) of the intake side camshaft 12. The upper end of an intake valve (not shown) provided for each cylinder is in contact with each cam 20, and the rotation of the cam 20 drives the intake valve to open and close.

In the camshaft 12 on the intake side, an enlarged diameter portion 21 is formed at a portion on the distal end side (left side in FIG. 1) from the portion supported by the cylinder head 18 and the bearing cap 19. An annular driven gear 22 is rotatably fitted on the outer periphery of the enlarged diameter portion 21. A plurality of external teeth 22a are provided on the outer peripheral portion of the driven gear 22.
The external teeth 22a are meshed with the external teeth 24a of a drive gear 24 provided on the exhaust-side camshaft 23 as shown in FIG. 3 (the drive gear 24 is not shown in FIG. 1). doing).

A plurality of cams 25 (four in this embodiment) are formed on the exhaust-side camshaft 23, similarly to the intake-side camshaft 12. An exhaust valve (not shown) is opened and closed by these cams 25. A cam pulley 26 is fixed to an end of the exhaust-side camshaft 23, and a timing belt 27 is mounted on the pulley 26. Timing belt 27
Is a crank pulley (not shown) attached to a crankshaft (not shown) which is an output shaft of the engine.
It is mounted on.

When the operation of the engine is started, the rotational driving force of the crankshaft is transmitted to the exhaust side camshaft 23 via the cam pulley 26, and the rotational driving force is transmitted to the drive gear 24 and the driven gear 22.
And transmitted to the intake-side camshaft 12 via the

FIGS. 4 and 5 are sectional views taken along the line IV-IV of FIG. 1 (FIG. 1 corresponds to the section II of FIG. 5). FIG. 4 shows a state where the intake side camshaft 12 is at the most retarded angle with respect to the crankshaft (the opening / closing valve timing of the intake valve is the latest). FIG. , The state of the most advanced angle (the opening and closing valve timing of the intake valve is the earliest).

As shown in FIG. 4, the VVT mechanism 11 provides a housing 28, a vane body 31 disposed in the housing 28, and a rotational force in a direction around the axis of the intake-side camshaft 12 to provide the same. An advance hydraulic chamber 13 and a retard hydraulic chamber 14 for rotating the vane body 31 are provided.

The housing 28 has a substantially hollow disk shape as a whole, and the side surface thereof is
2 and is fixed to the gear 22 together with a cover 38 to be described later by a plurality of bolts 30. Therefore, the housing 28, the driven gear 22, and the cover 38 can rotate integrally with the intake side camshaft 12 as a rotation axis. In this embodiment, the housing 2
8 and the cover 38 are formed of an iron-based sintered metal material.

On the other hand, the vane body 31 has an annular central portion 31a located at the center thereof and four vanes 32 formed on the outer periphery of the central portion 31a. Each vane 32 extends radially in the radial direction of the intake-side camshaft 12 and has a substantially cross shape as a whole. Each vane 32 is symmetrically arranged with respect to the axis of the intake camshaft 12. In the present embodiment, the vane body 31 is formed of a material having a larger thermal expansion coefficient than the housing 28 and the cover 38, for example, aluminum.

In the interior of the housing 28, four projections 33 projecting toward the axis of the intake-side camshaft 12 are formed at predetermined intervals in the circumferential direction of the intake-side camshaft 12. . The inner peripheral surface of each of the projections 33 is in sliding contact with the outer peripheral surface of the central portion 31a of the vane body 31.

Further, in the housing 28, each projection 3
A groove (recess) 34 is formed between the three. Each of the vanes 32 is disposed in the groove 34, and both side surfaces thereof are provided with a cover 38 as shown in FIG.
It is in sliding contact with the driven gear 22 and the enlarged diameter portion 21 respectively. The outer peripheral surface of each vane 32 is
Is in sliding contact with the inner peripheral surface.

An outer peripheral groove 35 having a rectangular cross section is formed in the outer peripheral portion of each vane 32. This outer circumferential groove 35
Seal members 36 are respectively disposed inside, and each seal member 36 is urged toward the outer peripheral side by a leaf spring 37. As a result, the outer peripheral surface of the vane 32 and the inner peripheral surface of the housing 28 are sealed by the seal member 36, and the movement of oil between the advance hydraulic chamber 13 and the retard hydraulic chamber 14 is regulated. It has become.

As shown in FIG. 1, a disk-shaped cover 38 is provided at the foremost portion of the intake-side camshaft 12 so as to cover the housing 28 and the tip side surface of the vane body 31. ing. At the center of the cover 38, a mounting hole 39 for mounting the vane body 31 to the camshaft 12 is formed. The vane body 31
A central hole 40 is formed in the central portion of. The mounting bolt 29 inserted into the center hole 40 is screwed into a bolt hole 41 of the intake-side camshaft 12, so that the vane body 31 is fixed to the tip of the intake-side camshaft 12. Further, the vane body 31 and the intake camshaft 1
2 has its phase fixed by a knock pin (not shown).

On the other hand, the space surrounded by the inner peripheral wall of each groove 34, the cover 38, and the driven gear 22 is divided into two hydraulic chambers by the vanes 32.
The hydraulic chamber 14 formed on the same side as the rotation direction (shown in FIG. 4) of the intake side camshaft 12 is a retard side hydraulic chamber, and is formed on the side opposite to the rotation direction. The set hydraulic chamber 13 is an advanced hydraulic chamber.

Oil is supplied to the inside of each of the hydraulic chambers 13, 14 through advance-side and retard-side hydraulic passages P 1, P 2, which will be described later.
In accordance with the magnitude of the hydraulic pressure in each of the hydraulic chambers 13 and 14 acting on the intake camshaft 12 (hereinafter, this rotational direction is referred to as an “advanced rotational direction”), or The shaft 12 can rotate in a direction opposite to the rotation direction (hereinafter, this rotation direction is referred to as a “retarded rotation direction”).

On the other hand, as shown in an enlarged manner in FIG. 8, one of the vanes 32 is formed with an insertion hole 42 having a circular cross section extending in the axial direction of the intake camshaft 12. Is provided with a lock pin 43. Describing in more detail, the insertion hole 42 has a step portion 42a in the middle thereof, and has a shape in which a portion on the tip side (left side in FIG. 8) from the step portion 42a is enlarged in diameter.

The lock pin 43 has a cylindrical shape with a bottom, and an enlarged diameter portion 43a is formed at a tip portion thereof. The lock pin 43 is configured to move in the axial direction of the intake camshaft 12 with its outer peripheral surface slidably contacting the inner peripheral surface of the insertion hole 42.

The annular space surrounded by the inner peripheral side surface of the insertion hole 42 and the outer peripheral side surface of the lock pin 43 defines a hydraulic chamber 44 for releasing the locked state of the lock pin 43. Have been. This hydraulic chamber 44
For example, the first pressure oil passage 4 formed inside the vane body 31
5, is communicated with the advance-side annular passage 46 described later.

On the other hand, a housing hole 47 extending in the axial direction is formed inside the lock pin 43, and a spring 48 as urging means is disposed in the hole 47. The lock pin 43 is biased by the spring 48 toward the base end side of the intake camshaft 12, that is, toward the driven gear 22 side.

On the tip side surface of the driven gear 22,
At the position facing the base end face of the lock pin 43, the pin 4
Locking hole 49 as a locking portion into which the base end portion of 3 can be fitted.
Are formed. When the lock pin 43 urged by the spring 48 fits into the locking hole 49, the relative rotation between the vane body 31 and the driven gear 22 is restricted.
As a result, the intake-side camshaft 12, the vane body 31, the driven gear 22, and the housing 28 rotate integrally. Further, the locking hole 49 is communicated with one of the advance hydraulic chambers 13 by a second pressure oil passage 50 formed on a side portion of the vane 32, for example. When the lock pin 43 is locked as shown in FIG. 4, the locking hole 49 causes the vane body 31 to move in a state where the rotational phase of the intake-side camshaft 12 is most advanced with respect to the housing 28, that is, It is provided so as to be in the advanced position. FIG. 5 shows the vane body 31 fixed at the most advanced position.

Next, advancing-side and retarding-side hydraulic passages P1 and P2 constituting a pressure passage for supplying oil to the advancing-side hydraulic chamber 13 and the retarding-side hydraulic chamber 14, and an oil control valve A configuration such as 16 (hereinafter referred to as “OCV”) will be described.

As shown in FIG. 1, the advance head oil passage 53 and the retard head oil passage 5 are provided inside the cylinder head 18.
4 are formed. Each of the head oil passages 53 and 54 is
An oil pan 57 can be connected via the CV 16, the oil filter 55, the oil pump 15, and the oil strainer 56. When the oil pump 15 is driven with the operation of the engine, the oil stored in the oil pan 57 is sucked by the pump 15. Then, the oil is introduced into the oil pump 15 via the oil strainer 56, and is pressurized and discharged from the pump 15. The discharged oil is supplied to the oil filter 55.
, And is selectively pumped to the head oil passages 53 and 54 by the OCV 16.

Oil grooves 58, 59 are formed in the upper end portion of the cylinder head 18 and the bearing cap 19 so as to surround the outer periphery of the journal 12a, and the head oil passages 53, 54 are formed in the respective oil grooves 58. , 59.

A retard-side shaft oil passage 60 extending in the axial direction is formed inside the intake-side camshaft 12, and the tip end thereof communicates with the bolt hole 41. A circumferential groove 6 extending in the circumferential direction is provided on the outer peripheral portion of the enlarged diameter portion 21.
1 is formed, and the groove 61 and the distal end side of the retard-side shaft oil passage 60 are communicated by a communication oil passage 62.

A retard-side oil hole 63 extending in the radial direction of the intake-side camshaft 12 is formed inside the journal 12a. The retard shaft oil passage 60 communicates with the one oil groove 59 through the retard oil hole 63.

An advanced shaft oil passage 64 is formed inside the intake camshaft 12 and extends in a direction inclined with respect to the axial direction. An advance-side oil hole 65 extending in the radial direction of the intake-side camshaft 12 is formed inside the journal 12a. The advance shaft oil passage 6
The base end side of the oil passage 4 communicates with the other oil groove 58 through the advanced oil hole 65.

As shown in FIG. 4 and the like, the driven gear 22 is formed with four cut grooves 66 having a fan-shaped cross section.
The peripheral groove 61 and each retard side hydraulic chamber 14 are formed by each cut groove 66.
And are communicated.

Further, on the side surface on the distal end side of the enlarged diameter portion 21,
As shown in FIG. 1, a cylindrical protrusion 67 protruding toward the distal end side is provided.
Are formed. A step portion 68 is formed on the base end portion of the vane body 31 so as to surround the projecting portion 67. The inner peripheral wall of the step 68 and the protrusion 67
The space enclosed by the diameter-enlarging portion 21 forms a ring-shaped advance-side annular passage 46. The leading end of the advance shaft oil passage 64 opens into the advance annular passage 46.

Further, inside the vane body 31, FIG.
As shown in FIG. 5, four advance-side supply oil holes 69 extending radially are formed, and the inner peripheral side of the oil hole 69 communicates with the advance-side annular passage 46. Further, the outer peripheral side of each advance side supply oil hole 69 is open to each advance side hydraulic chamber 13 described above.

As described above, the advance side head oil passage 53 and the oil groove 5
8, the advance-side oil hole 65, the advance-side shaft oil passage 64, the advance-side annular passage 46, and each advance-side supply oil hole 69 constitute an advance-side hydraulic passage P1. Oil passage 5
4. Oil groove 59, retard side oil hole 63, retard side shaft oil passage 6
0, the communication oil passage 62, the circumferential groove 61, and each of the cut grooves 66 constitute a retard side hydraulic passage P2.

In the present embodiment, oil is supplied from the oil pump 15 into the hydraulic chambers 13 and 14 by switching the communication state between the hydraulic passages P1 and P2 and the oil pump 15 and the oil pan 57 by the OCV 16. Alternatively, the oil is drained from the hydraulic chambers 13 and 14 and the oil pan 5
It is going to return to 7.

The OCV 16 is controlled in duty by controlling the opening thereof, so that the advance-side and retard-side hydraulic chambers 13,
14 is for controlling the hydraulic pressure supplied to 14. Hereinafter, the configuration of the OCV 16 will be described.

As shown in FIG. 1, a casing 70 constituting the OCV 16 has first to fifth ports 71 to 75. The first port 71 is in communication with the advance side head oil passage 53, and the second port 72 is in communication with the retard side head oil passage 54. Also, the third and fourth ports 73, 7
4 is connected to an oil pan 57, and the fifth port 75 is connected to the discharge side of the oil pump 15 via an oil filter 55.

A skewer-shaped spool 76 is provided inside the casing 70. The spool 76 has four columnar valve bodies 77, which can reciprocate in the axial direction. The casing 70 is provided with an electromagnetic solenoid 78 for moving the spool 76 between a first operating position shown in FIG. 1 and a second operating position shown in FIG. A spring 79 is provided in the casing 70, and the spring 79
Are biased toward the first operating position.

The OCV 16 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 17 shown in FIG. The ECU 17 is connected to a rotation speed sensor 80 and an intake pressure sensor 81 for detecting an operating state of the engine, and a crank angle sensor 82 and a cam angle sensor 83 for detecting a rotation phase of the intake camshaft 12. And
The ECU 17 determines the operating state of the engine and the intake camshaft 12 based on the detection signals of the sensors 80 to 83.
Is detected. And EC
U17 determines a deviation between the actual rotation phase of the intake-side camshaft 12 and a target rotation phase suitable for the operating state of the engine, and controls the OCV 16 so that the deviation is equal to or less than a predetermined value.

Next, a hybrid system and an intake valve timing of a hybrid vehicle to which the present embodiment is applied will be described with reference to FIG. 6 and FIG. FIG.
Shows a system configuration of a hybrid system. The system includes an engine 90, a generator 91, an inverter 92, a battery 93, a motor 94, a speed reducer 95, a power split device 96, a tire 97, and the like. Further, a transmission mechanism 98 is formed by the generator 91, the motor 94, the speed reducer 95, and the power split mechanism 96. Here, the generator 91 also has a function of a starter motor that starts the engine 90 via the power split device 96 under the control of the inverter 92 by the ECU 17.

The running mode of the hybrid vehicle includes an engine mode in which the vehicle is driven by the engine 90, a motor mode in which the vehicle is driven by the motor 94, and a combined mode in which the vehicle is driven by using both the engine 90 and the motor 94. There are three types. That is, when the vehicle is running at high speed, the engine mode is set. When the vehicle is running at low speed and the accelerator pedal depression amount is large,
For example, when climbing a slope while traveling at low speed, the combination mode is set. The motor mode is set at the start of the vehicle or when the vehicle is running at a low speed and the accelerator pedal depression amount is small.

The engine 90 is operated by applying the Atkinson cycle, which is the high expansion ratio cycle described above, and the expansion ratio is higher than the compression ratio. At this time, in order to obtain a low compression ratio, the VVT mechanism 1
7, the closing timing of an intake valve (not shown) is greatly delayed in the compression stroke as shown in FIG. 7, for example. As a result, the actual compression starts after the intake valve is closed, shortening the compression stroke period, lowering the compression ratio,
The expansion ratio is larger than the compression ratio.

Next, the operation of the adjusting device for an internal combustion engine according to the present embodiment configured as described above will be described. Note that the adjustment device includes the VVT mechanism 11 and the OCV 1
6. It is composed of a generator (starter motor) 91, the ECU 17, and the like.

In such a hybrid system, as described above, the engine 9 operating at a low compression ratio is used.
When starting 0, a sufficient start may not be obtained unless sufficient compression pressure is applied to the air-fuel mixture. Therefore, only at the time of starting, it is necessary to advance the valve timing of the intake valve, that is, to lengthen the compression stroke to secure a sufficient compression pressure. Therefore, the ECU 17 sets the inverter 92
, A crankshaft (not shown) is forcibly rotated by a predetermined amount by a generator (starter motor) 91 in a direction opposite to the rotation direction during operation of the engine 90. At this time, the intake camshaft 12 is fixed without rotating due to the friction (friction) generated between the intake cam 20 and the intake valve, and the housing 28 drivingly connected to the crankshaft.
Only, the intake camshaft rotates in a direction opposite to the rotation direction of the intake camshaft shown in FIGS. This has the same effect as advancing the intake camshaft. Finally, FIGS.
As shown in FIG. 7, the lock pin 43 is locked in the locking hole 49, and the intake camshaft 12 is locked in the most advanced state. As a result, the valve timing of the intake valve is advanced at the time of starting, that is, the compression stroke can be lengthened to ensure a sufficient compression ratio.

Further, as described above, the vane body 31 is formed of a material having a larger thermal expansion coefficient than the housing 28 and the cover 38, for example, aluminum. Therefore, even at the time of low-temperature start (start in severe cold conditions such as -20 ° C) in which the viscosity of the lubricating oil increases, due to the difference in the coefficient of thermal expansion,
8, the clearance C between the vane body 31, the housing 28, and the cover 38 is ensured. That is,
The clearance C of the vane body 31 is smaller than that of the housing 2.
8 and the cover 38 are contracted more greatly than those of the cover 8 and the cover 38. As a result, even if the viscosity of the lubricating oil is high, it is possible to lock the intake camshaft 12 in the most advanced state in a state where the sliding resistance between the vane body 31 and the housing 28 and the cover 38 is small. That is, even in severe cold, the engine 90 can be smoothly advanced.

Subsequently, after a predetermined time has elapsed after the operation of the engine 90 has been started, the oil pump 15 is driven to
5 discharges oil. The discharged oil is the OCV1
The hydraulic pressure is supplied from one of the hydraulic passages P1 and P2 selected by 6 to the hydraulic chambers 13 and 14 of either the advance hydraulic chamber 13 or the retard hydraulic chamber 14. At this time, oil is supplied to the inside of the hydraulic chamber 44 or the locking hole 49 through the first pressure oil passage 45 or the second pressure oil passage 50.

When the hydraulic pressure in the hydraulic chamber 44 or the inside of the locking hole 49 increases to a predetermined value or more, initially, as shown in FIG.
The lock pin 43 in the state shown in (1) moves toward the distal end of the intake side camshaft 12 against the urging force of the spring 48 by the oil pressure. By this movement, the locking of the vane body 31 is released, and the relative rotation of the vane body 31 with respect to the housing 28 becomes possible.

As shown in FIG. 1, in the OCV 16, when the spool 76 is placed in the first operating position by the urging force of the spring 79, the discharge side of the oil pump 15 and the retard side head oil passage 54, and the advance side head oil passage 53 and the oil pan 57 are communicated. Therefore,
While oil is supplied to each of the retard hydraulic chambers 14 through the retard hydraulic passage P2, the oil in each of the advance hydraulic chambers 13 is returned to the oil pan 57 through the advance hydraulic passage P1.

As a result, each of the vanes 32 has a corresponding one of the retard-side hydraulic chambers 1, which is relatively higher than the hydraulic pressure of each of the advance-side hydraulic chambers 13.
4, the vane body 31 is rotated relative to the housing 28 in the retard rotation direction indicated by the arrow B in FIG. Thus, the vane body 31 is
8, the intake camshaft 1
As a result, the opening / closing timing of the intake valve is delayed.

On the other hand, as shown in FIG.
When the spool 76 is located at the second operating position against the urging force of the oil pump 15, the discharge side of the oil pump 15 communicates with the advance head oil passage 53, and the retard head oil passage 54 communicates with the oil pan. 57 is communicated. Therefore, while the oil is supplied to each advance-side hydraulic chamber 13 through the advance-side hydraulic passage P1,
The oil in each retard side hydraulic chamber 14 is returned to the oil pan 57 via the retard side hydraulic passage P2.

As a result, the vane 32 is urged by the hydraulic pressure in each advance-side hydraulic chamber 13 which is relatively increased from the hydraulic pressure in each retard-side hydraulic chamber 14. 5 rotates in the advance rotation direction indicated by the arrow A in FIG. By rotating the vane body 31 with respect to the housing 28 in this manner, the rotational phase of the intake-side camshaft 12 advances as compared with the driven gear 22, so that the opening and closing timing of the intake valve is advanced.

As described above, the intake-side camshaft 1
When the rotation phase of the OCV 16 is changed and the deviation between the rotation phase and the target rotation phase adapted to the operating state of the engine becomes equal to or smaller than a predetermined value, the ECU 17 sets the first port 71 and the second port 72 of the OCV 16 to both ports. The spool 7 is moved so that 71 and 72 are closed by the valve body 77.
The position of the spool 6 is controlled (hereinafter, the position of the spool 76 is referred to as an “intermediate holding position”). Thus, the spool 76
When the position of the hydraulic chamber 13 becomes the "intermediate holding position",
The supply of oil to the hydraulic chamber 4 and the discharge of oil from the hydraulic chambers 13 and 14 are not performed. Since each vane 32 is held from both sides by the hydraulic pressure in each of the hydraulic chambers 13 and 14, the rotation of the vane body 31 is restricted, and the housing 2
The position of the vane body 31 in the rotation direction with respect to 8 is fixed. As a result, the opening / closing timing of the intake valve is maintained at a predetermined timing.

Here, in the present embodiment,
Thus, the vane body 31 connects the housing 28 and the cover 38.
Made of a material with a higher coefficient of thermal expansion than the constituent material
Have been. Due to this difference in the coefficient of thermal expansion,
The gap of the clearance C which existed at
The vane body 31 and the housing 28
Oil is prevented from leaking from the gap with the cover 38.
You. Incidentally, the housing 28 and the cover 38 are thermally expanded.
Coefficient (linear expansion coefficient) 1.2 × 10^-Five/ C is iron-based material
And the vane body 31 has a thermal expansion coefficient (linear expansion coefficient).
Number) 2.4 × 10 ^-Five/ ° C for aluminum-based materials
The VVT mechanism 11 of the present embodiment
For example, between -30 ° C and 120 ° C, approximately 40μ
m clearance C is obtained.

The effects obtained by the above-described embodiment will be described below. In the present embodiment, the vane body 31 is formed of a material having a larger thermal expansion coefficient than the housing 28 and the cover 38, for example, aluminum. Therefore, even at the time of a low temperature start (the temperature is extremely cold at −20 ° C. or the like) when the viscosity of the lubricating oil increases, the clearance C between the vane body 31 and the housing 28 and the cover 38 is determined based on the difference in the thermal expansion coefficient. Is secured. As a result, the intake camshaft 12 can be locked in the most advanced state without bothering the sliding resistance between the vane body 31 and the housing 28 and the cover 38 and the viscosity of the lubricating oil. That is, even in severe cold, the engine 90 can be smoothly advanced. Further, at high temperatures, the gap of the clearance C, which was initially present at the time of low temperature starting, is narrowed as the oil temperature rises due to the difference in the coefficient of thermal expansion.
Oil is prevented from leaking from the gap between the housing 28 and the cover 38.

The above embodiment can be embodied by changing the configuration as follows. In the above embodiment, the housing 28 and the cover 38 are formed of an iron-based sintered metal material, and the vane body 31 is formed.
Is formed of aluminum, but the present invention is not limited to this. In short, it is only necessary that the constituent materials are determined so that the thermal expansion coefficients of the constituent materials of the vane body 31 are larger than the thermal expansion coefficients of the constituent materials of the housing 28 and the cover 38. At this time, the materials are selected so as to secure the required clearance C in the temperature environment in which the adjusting device for the internal combustion engine is used.

In the above embodiment, the housing 28 and the cover 38 are formed of an iron-based sintered metal material. However, the present invention is not limited to this. Only the cover 38 may be formed of an iron-based sintered metal material. . Even in this case, it is desirable that the housing 28 be made of a material having a smaller coefficient of thermal expansion than the vane body 31.

In the above embodiment, the locking holes 49
When the lock pin 43 is locked to the housing 2, the rotational phase of the vane body 31,
8 so as to be the most advanced angle to 8
However, the position of the locking hole 49 is not limited to this. That is, it may be provided at a position corresponding to the advance angle required according to the compression ratio.

In the above embodiment, the engine 9
Although the configuration is such that the starter motor 0 is also used as the generator 91, a configuration in which a starter motor is separately provided may be employed. In the above embodiment, the hydraulic chambers 13 and 14 are provided on both sides of the vane 32. However, the present invention is not limited to this, and only one of them may be provided. In that case, the other side is provided with a biasing member such as a spring.

In the above embodiment, the driven gear 22 is changed to a cam pulley, and the VVT mechanism 11 is changed to a configuration in which a timing belt is mounted on the pulley, and the pulley is directly driven by the rotational driving force of the crankshaft. It may be driven to rotate.

In the above embodiment, the vane body 3
Although the configuration in which four vanes 32 are formed in one is adopted,
A configuration having three or less or five or more vanes 32 is also possible. When the number of the vanes 32 is smaller than that in each of the above embodiments, the configuration of each of the hydraulic passages P1 and P2 can be simplified. A larger rotation torque can be applied.

In the above embodiment, the VVT mechanism 11 having a configuration in which the cam pulley 26 is changed to a timing sprocket and the timing belt 27 is changed to a timing chain may be adopted.

In the above embodiment, the exhaust camshaft 23 is driven and connected to the crankshaft. However, the intake camshaft 12 may be driven and connected to the crankshaft.

In the above embodiment, an example in which the internal combustion engine adjusting device according to the present invention is applied to a hybrid vehicle has been described. However, the present invention is not limited to this, and the operation is performed with the compression ratio set lower than the expansion ratio. Any internal combustion engine may be used, and its application is not limited to automobiles. For example, it can be mounted on transportation means such as ships and airplanes and various other industrial machines.

In addition, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects. (1) The internal combustion engine adjusting device according to claim 1 or 2, wherein the internal combustion engine is connected to a motor for a prime mover.

According to this structure, in an internal combustion engine connected to a motor for a prime mover, for example, an internal combustion engine of a hybrid vehicle, the advance of the intake valve at the time of the low-temperature start can be smoothly performed and the fluid at the time of the warm operation can be smoothly increased. Leakage can be prevented. Therefore, the efficiency of the internal combustion engine can be improved.

(2) The internal combustion engine adjusting apparatus according to the above (1), wherein the generator for charging the battery also serves as a motor for rotatingly driving the engine output shaft. According to the configuration, the generator for charging the battery can also serve as the motor for rotatingly driving the engine output shaft. Therefore, the weight of the vehicle can be reduced as compared with a configuration in which the motor is separately provided. as a result,
For example, fuel efficiency of a hybrid vehicle is improved.

(3) The adjusting device for an internal combustion engine according to any one of (1) and (2), wherein the liquid whose hydraulic pressure is controlled is oil. According to the same configuration,
Since the hydraulic pressure control of the VVT mechanism using the lubricating oil of the internal combustion engine becomes possible, the manufacture of the adjusting device for the internal combustion engine becomes easier as compared with the case where other hydraulic pressure controls are used. Further, the oil also functions as a lubricating oil for the VVT mechanism.

(4) The internal combustion engine is a gasoline engine of a hybrid vehicle, the motor for the prime mover is the drive motor of the vehicle, and the liquid whose hydraulic pressure is controlled is oil. Adjustment device for internal combustion engine.

According to this configuration, in a hybrid vehicle to which the Atkinson cycle is applied, the engine can be smoothly started at a low temperature, and oil leakage from the VVT mechanism can be prevented.

[0078]

According to the first aspect of the present invention, there is provided an internal combustion engine which is operated in a state where the compression ratio is set lower than the expansion ratio. The advance angle of the valve can be smoothly adjusted, and liquid leakage from the variable valve timing mechanism during a warm state can be suitably prevented.

According to the second aspect of the present invention, the advance angle adjustment and the prevention of liquid leakage can be easily and suitably performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of an adjusting device for an internal combustion engine according to the present invention.

FIG. 2 is a partial cross-sectional view showing an example of an operating state of the OCV.

FIG. 3 is a plan view showing the valve operating structure of the embodiment.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 1;

FIG. 5 is a sectional view showing an example of an operation state of the VVT.

FIG. 6 is a schematic configuration diagram of a vehicle on which the adjusting device for an internal combustion engine according to the present invention is mounted.

FIG. 7 is an explanatory diagram showing opening and closing timings of a valve.

FIG. 8 is an enlarged sectional view showing the periphery of a lock pin.

[Explanation of symbols]

11 VVT mechanism (valve timing mechanism), 12 intake camshaft, 13 advance hydraulic chamber, 14 retard hydraulic chamber, 16 OCV (oil control valve),
17 ECU (electronic control unit), 18 cylinder head, 22 driven gear, 28 housing, 31 vane body, 32 vane, 38 cover, 42 insertion hole,
43: lock pin, 45: first pressure oil passage, 48: spring, 49: locking hole, 50: second pressure oil passage, 90: engine, 91: generator (starter motor), 92: inverter, 93 ... Battery, 94 ... motor.

Claims (2)

[Claims] A first rotating body connected to one and the other of a camshaft having an identical rotation axis and driving an engine output shaft and an engine valve to open and close; A liquid chamber is formed on at least one side of the vane by dividing a recess formed in the body with a vane formed in the second rotating body, and the first and the second liquid chambers are controlled based on a liquid pressure control for the formed liquid chamber. A variable valve timing mechanism that changes a relative rotation phase between the engine output shaft and the camshaft by relatively rotating a second rotating body; and an electric motor that can externally drive the engine output shaft. An adjusting device for an internal combustion engine, wherein at the time of starting, the advance angle of the variable valve timing mechanism is adjusted by forcibly rotating the engine output shaft by the electric motor, wherein the first variable valve mechanism comprises the first variable valve timing mechanism. And an adjusting device for the internal combustion engine, wherein each material of the second rotating body is selected so as to satisfy a relation of a thermal expansion coefficient of the first rotating body <a thermal expansion coefficient of the second rotating body. 2. The internal combustion engine adjusting device according to claim 1, wherein said first rotating body is formed of an iron-based material, and said second rotating body is formed of an aluminum-based material.