JP2003214123A - Valve timing adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve timing adjusting device capable of preventing startability during next starting from extremely worsening even when an engine is stopped irregularly due to an engine stall. <P>SOLUTION: An advance angle restriction groove 17 is formed in a housing member 2 so that it can move with the head part of a rock pin 13 protruding from a vane 10. The advance angle restriction groove 17 is formed that an end part on the delay side is set to a startable phase in which an engine can start. By releasing an oil pressure on the lock pin 13 by turning OFF a second oil pressure control valve 6 during idling, the lock pin 13 is pushed out from the vane 10, and the head part of the lock pin 13 is fitted in an advance angle restriction groove 17. Thus, since even when the engine is abnormally stopped due to an engine stall during idling, rotation of a rotor to the lag angle side (most lag angle side) can be blocked, startability during next starting can be prevented from extremely worsening. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing adjusting device for varying the opening / closing timing of an intake valve or an exhaust valve of an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique of changing the phase of an intake valve or an exhaust valve of an internal combustion engine to improve output and fuel efficiency. For example, in the high engine speed range of an internal combustion engine, even if the piston starts heading toward top dead center, intake air tries to enter the cylinder further due to inertia, so by delaying the closing timing of the intake valve from the piston bottom dead center,
The volumetric efficiency is improved and the output of the internal combustion engine can be improved.

However, if the intake valve is closed later than the bottom dead center of the piston, the output after engine warm-up is improved, but at the time of engine start, since the intake air has no inertia, the compression ratio does not rise (the actual compression ratio is insufficient. However, since the air temperature at the top dead center of the piston does not rise sufficiently, it becomes difficult to start the engine. There is also a problem that the idling stability becomes poor. That is, when changing the phase of the intake valve, the optimum valve timing at the time of starting the engine is different from the optimum valve timing for improving the fuel consumption output after the engine is warmed up.

In order to solve the above problems, there is a valve timing adjusting device which the applicant of the present invention has previously filed (Japanese Patent Application No.
01-285280). This valve timing adjustment device has a lock pin that can hold the rotor at a position (called a lock phase) in which the rotor has advanced by a predetermined angle from the most retarded phase, and this lock pin is used as a dedicated hydraulic control valve. The configuration is controlled by. The lock pin is fitted into the lock recess when the engine is stopped to hold the rotor in the lock phase, so that a predetermined valve timing suitable for starting the engine is obtained. Further, after the engine is started, the lock pin is disengaged from the lock recess, so that the rotor can rotate further toward the retard side than the lock phase, and the valve timing can be changed to both the retard side and the advance side.

[0005]

However, in the above prior art, if the engine stops abnormally due to engine stall during idling after starting the engine, the cam torque causes the rotor to move to the most retarded phase and stops. There was a problem that it would be difficult to start the engine. The present invention was made based on the above circumstances, and its purpose is to:
An object of the present invention is to provide a valve timing adjusting device capable of preventing the startability at the next start from being extremely deteriorated when the engine abnormally stops due to an engine stall or the like.

[0006]

(Means for Solving the Problems) (Means for Claim 1) A valve timing adjusting device according to the present invention comprises a lock pin capable of restraining a rotor in a lock phase, and a second hydraulic pressure controlling means for operating the lock pin. It has a hydraulic control valve and a guide groove that guides the head of the lock pin so that the head of the lock pin can move while protruding from the vane when the rotor is advanced toward the lock phase. The end of the guide groove on the retard side is set to a startable phase in which the engine can be started between the lock phase and the most retarded phase, and the second hydraulic control valve controls the lock pin at the idle time. The hydraulic pressure for the lock pin is controlled so that the head protrudes from the vane and fits in the guide groove.

According to this structure, since the head of the lock pin projects from the vane and fits into the guide groove during idling, even if the engine is abnormally stopped due to engine stall during idling, the rotor is at the most retarded phase. It does not move up to and can be stopped in a startable phase in which the head of the lock pin abuts on the retard side end of the guide groove. By setting the startable phase on the advance side of the most retarded phase (between the most retarded phase and the lock phase), the valve timing at which the engine can be started can be obtained.
As a result, even if the engine stops abnormally during idling, it is possible to prevent the engine startability at the next start from being extremely deteriorated.

(Means of claim 2) In the valve timing adjusting device according to claim 1, the first hydraulic control valve presses the lock pin against the end of the guide groove set to the startable phase during idling. In order to achieve this, a retard angle pressure is applied to the rotor. In this case, the behavior of the rotor can be stabilized by pressing the lock pin against the end of the guide groove, and deviation of the valve timing can be prevented.

(Means for Claim 3) In the valve timing control apparatus according to claim 2, the first hydraulic control valve is delayed relative to the rotor when the oil temperature during idling or the engine cooling water temperature is equal to or higher than a predetermined temperature. It is characterized by applying an angular pressure. The higher the oil temperature, the lower the oil pressure and the more difficult it is to control the fluttering of the rotor. Therefore, when the oil temperature is high (when the oil temperature or the engine cooling water temperature is higher than a specified temperature), retard angle pressure is applied to the rotor. By pressing the lock pin against the end of the guide groove, the flap of the rotor due to the torque fluctuation of the cam shaft can be prevented.

(Means of claim 4) In the valve timing adjusting device according to any one of claims 1 to 3, the lock pin is biased by a spring in a direction of being pushed out from the vane, and at the same time, a second hydraulic control is provided. The hydraulic pressure supplied from the valve acts in the direction to push the lock pin back into the vane against the biasing force of the spring, and the second hydraulic control valve stops the hydraulic pressure supply to the lock pin during idling. And In this configuration, when the supply of the hydraulic pressure to the lock pin is stopped by the second hydraulic control valve, the lock pin is pushed out of the vane by the urging force of the spring and the pin head is fitted into the guide groove. Therefore, at the time of idling, by stopping the power supply to the second hydraulic control valve, the power consumption can be reduced and the fuel consumption can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is an axial plan view showing an internal structure of a valve timing adjusting device, and FIG. 2 is a system diagram showing a valve timing adjusting device (radial sectional view) and a hydraulic circuit. Valve timing adjusting device 1 (hereinafter referred to as VVT)
Includes a housing member 2 that is rotated by transmitting the rotational force of the engine, and a rotor 4 that is fixed to a camshaft 3 for opening and closing an intake valve or an exhaust valve of the engine, and a hydraulic circuit (see FIG. 2). Is hydraulically controlled via a first hydraulic control valve 5 and a second hydraulic control valve 6 provided in the.

The housing member 2 is rotatably fitted to an end portion of a cam shaft 3 to which a rotor 4 is fixed, and a rotational force is transmitted by a chain drive from a drive shaft (not shown) of the engine to drive the drive shaft. It rotates in synchronization with. As shown in FIG. 1, the housing member 2 is provided with four fan-shaped recesses 2a on the inner side in the circumferential direction. Between the recess 2a and the rotor 4, there are hydraulic chambers (the retard chamber 7 and the advance chamber). 8) is formed.

The rotor 4 is fixed to the camshaft 3 by a bolt 9 (see FIG. 2) inserted in the center of the boss portion 4a, with the boss portion 4a of the rotor 4 abutting on the end surface of the camshaft 3. . The rotor 4 is provided with four vanes 10 around the boss portion 4a, and each vane 10 is housed in a fan-shaped recess 2a provided in the housing member 2,
The hydraulic chamber is divided into a retard chamber 7 and an advance chamber 8. Also,
As shown in FIG. 2, the rotor 4 is biased toward the advance side by a spring 11 interposed between the housing member 2 and the rotor 4.

A retard limit pin 12 is provided on one vane 10.
And the lock pin 13 are incorporated. The retard limit pin 12 prevents the rotor 4 from rotating further toward the retard side from the lock phase (described below) when the engine is stopped (except for abnormal stop due to engine stall or the like), and as shown in FIG. In addition, it is incorporated in the vane 10 so as to be able to move forward and backward, and operates by the balance between the urging force of the spring 14 and the hydraulic pressure applied to the flange portion of the retard angle limiting pin 12. Specifically, when hydraulic pressure is applied to the flange portion of the retard angle limiting pin 12, the retard angle limiting pin 12 is pushed back into the vane 10 against the urging force of the spring 14, and when the hydraulic pressure is released, the spring is released. Being biased by 14, the head of the retard angle limiting pin 12 projects from the vane 10.

The lock pin 13 locks the rotor 4 in the lock phase when the engine is stopped, and holds the rotor 4 in the startable phase (described below) when the engine abnormally stops during idling. As shown in FIG. 3, the vane 10 is incorporated in the inside of the vane 10 so as to be able to move forward and backward, and operates by the balance between the urging force of the spring 15 and the hydraulic pressure applied to the collar portion of the lock pin 13. Specifically, when hydraulic pressure is applied to the collar portion of the lock pin 13, the lock pin 13 is pushed back into the vane 10 against the biasing force of the spring 15, and when the hydraulic pressure is released, the spring 15 is biased. Then, the head of the lock pin 13 projects from the vane 10.

The above-mentioned lock phase is the rotor position (see FIG. 6 (b)) that can realize the optimum valve timing for starting the engine. The startable phase is the rotor position (see FIG. 6 (a)) that is set between the lock phase and the most retarded angle phase and that can realize the valve timing that enables engine start. In this embodiment, the idle phase (rotor position during idling) is set slightly ahead of the startable phase.

The housing member 2 includes a retard angle limiting pin 12
Angle limiting groove 16 for guiding the head of the retard angle limiting pin 12 so that the head of the user can move while protruding from the vane 10.
Similarly, an advance angle limiting groove 17 (guide groove of the present invention) for guiding the head of the lock pin 13 is provided so that the head of the lock pin 13 can move in a state of protruding from the vane 10. . However, the retard limit groove 16 is provided in a range where the rotor 4 can move between the lock phase and the most advanced phase, and the advance limit groove 17 allows the rotor 4 to move between the locked phase and the startable phase. It is provided within the range of movement. A lock recess 18 into which the head of the lock pin 13 can be fitted is provided in the lock phase of the housing member 2, and the advance angle limiting groove 1 is provided.
It is formed one step deeper than 7 (see FIG. 3).

The first hydraulic control valve 5, as shown in FIG.
The hydraulic pressure of the retard chamber 7 and the advance chamber 8 is controlled via the advance oil passage 19 and the retard oil passage 20, and an electromagnetic actuator 5a for driving a built-in spool (not shown) is provided. The duty of the current supplied to the electromagnetic actuator 5a is controlled by an ECU (electronic control unit) not shown. The second hydraulic control valve 6 is used for the pin control oil passage 2
The hydraulic pressure for the retard angle limiting pin 12 and the lock pin 13 is controlled via 1 and an electromagnetic actuator 6a for driving a built-in spool (not shown) is provided, and the energizing current for this electromagnetic actuator 6a is turned on by the ECU. / OFF is controlled.

Next, the operation of this embodiment will be described. a) During normal operation. During normal operation, the rotation limit of the rotor 4 by the retard limit pin 12 and the lock pin 13 is released so that the rotor 4 can rotate to the retard side or the advance side. That is, as shown in FIG. 4, when the energizing current to the second hydraulic control valve 6 is turned on, the hydraulic pressure is applied to the retard angle limiting pin 12 and the lock pin 13, and the hydraulic pressure overcomes the biasing force of the spring. The retard limit pin 12 and the lock pin 13 are pushed back into the vane 10 to release the rotation limit of the rotor 4. Further, the ECU duty-controls the energization current to the first hydraulic control valve 5 according to the operating state of the engine.

B) During normal stop. Normally, the idle phase is on the retard side with respect to the lock phase, so it is necessary to advance the VVT 1 to the lock phase when the engine is stopped. Therefore, it is considered that the advance angle control is performed at the same time as the ignition is turned off, and the engine is stopped by fuel cut and ignition cut after advancing to a predetermined phase.

Therefore, when the engine is normally stopped from the idling state, the advance angle control is performed at the same time as the ignition is turned off, and the second hydraulic control valve 6 is turned off to release the hydraulic pressure to the lock pin 13. 13 is fitted in the advance angle limiting groove 17 (see FIG. 5). When the VVT 1 is advanced in this state, the lock pin 13 comes into contact with the advance side end of the advance limiting groove 17 to stop the rotation of the rotor 4, and the head of the lock pin 13 is fitted into the lock recess 18. Together, the rotor 4 is constrained to the lock phase.

C) When the rotor 4 stops on the advance side. When the phase of VVT1 is stopped on the advance side due to engine stall, failure, etc. (see Fig. 6 (c)), the rotor position is set to the ECU.
Can be stored in. In this case, the VVT 1 is retarded at the next start, and the second hydraulic control valve 6
Is turned off to release the hydraulic pressure to the retard angle limiting pin 12, and the retard angle limiting pin 12 is fitted into the retard angle limiting groove 16. If the VVT 1 is retarded in this state, the rotor 4 is rotated to the retard side by the drive torque of the camshaft 3 even when there is no hydraulic pressure at the time of starting, so that the retard limit pin 12 of the retard limit groove 16 moves. The rotation of the rotor 4 is stopped by coming into contact with the retard side end.

The lock pin 13 and the retard limit pin 12 are
As shown in FIG. 6B, in the lock phase in which the head of the lock pin 13 fits into the lock recess 18, the retard limit pin 1
2 is positioned slightly ahead of the retard angle side end of the retard angle limiting groove 16. Therefore, the retard angle limiting pin 12 is not
When the rotor 4 is rotated to a position where it abuts against the retard angle side end of 6, the lock pin 13 can be fitted into the advance angle limiting groove 17. In this state, when the rotor 4 fluctuates due to the fluctuating torque of the camshaft 3 and moves to the advance side, the lock pin 13 comes into contact with the advance side end of the advance limiting groove 17 and can be locked. The head of the is fitted into the lock recess 18 to restrain the rotor 4 in the lock phase.

D) When the rotor 4 stops on the retard side. When the phase of VVT1 is stopped on the retard side due to engine stall, failure, etc. (see FIG. 6 (a)), the rotor position is set to the ECU.
Can be stored in. In this case, the VVT 1 is advanced and controlled at the next start, and the second hydraulic control valve 6
Is turned off to release the hydraulic pressure to the lock pin 13, and the lock pin 13 is fitted into the advance angle limiting groove 17. When the VVT 1 is advanced in this state, the lock pin 13 comes into contact with the advance side end of the advance limiting groove 17 to stop the rotation of the rotor 4, and the head of the lock pin 13 is fitted into the lock recess 18. Together, the rotor 4 is constrained to the lock phase. Even when there is no hydraulic pressure at the time of starting, it is possible to advance the angle by the biasing force of the spring 11 (see FIG. 2).

E) When stopped due to engine stall during idling. This is because when the rotor 4 stops on the retard side, it often stops abnormally due to engine stall during idling. In this case, the basic operation is the same as in the case of d) above, but when idling, the second hydraulic control valve 6 is turned off to release the hydraulic pressure to the lock pin 13, and the lock pin 13 is moved to the advance angle limiting groove 17 The difference is that it is fitted to. Even if the engine abnormally stops due to engine stall or the like in this state, the lock pin 13 is already fitted in the advance angle limiting groove 17, so that the phase is delayed from the startable phase which is the retard side end portion of the advance angle limiting groove 17. It is possible to prevent the rotor 4 from rotating to the angle side (the most retarded angle side).

(Effect of this embodiment) In the present invention, since the head of the lock pin 13 projects from the vane 10 and fits into the advance angle limiting groove 17 during idling, even when the engine is abnormally stopped due to engine stall or the like. The rotor 4 does not move to the most retarded phase, and it can be stopped at the startable phase in which the head of the lock pin 13 contacts the retarded side end of the advance limiting groove 17. This startable phase is set on the advance side (between the most retarded angle phase and the lock phase) of the most retarded angle phase, so that the valve timing at which the engine can be started can be obtained. It is possible to prevent the startability from being extremely deteriorated.

Further, in the conventional VVT, since the advance angle limiting groove is provided up to the most retarded phase, as shown in FIG. 7, when the engine abnormally stops, the rotor 4 retards to the most retarded phase, After that, the lock phase is advanced by the advance control, so that the swing of the rotor 4 becomes large, and the advance cannot be smoothly advanced. On the other hand, the VVT1 of this embodiment is
Since the rotor 4 stops in the startable phase even when the engine stops abnormally, the rotor 4 can be restrained from swinging during advance control as shown in FIG. 8, and the advance can be smoothly advanced. It is possible.

Further, when the energization of the second hydraulic control valve 6 is stopped, the hydraulic pressure applied to the lock pin 13 is released and the lock pin 13 is pushed out of the vane 10 by the urging force of the spring 15 to cause the lock pin 13 to move. The head has an advance restriction groove 17
To fit. Therefore, at the time of idling, since the lock pin 13 is pushed out of the vane 10 to stop the energization of the second hydraulic control valve 6, the power consumption is reduced and the fuel consumption can be improved.

(Second Embodiment) This embodiment is an example in which a retard angle pressure is applied to the rotor 4 in order to press the lock pin 13 against the end portion of the advance angle limiting groove 17 during idling. When the oil temperature is high, the oil pressure is low and it becomes difficult to suppress the fluttering of the rotor 4. Therefore, when the oil temperature is high, a retard angle pressure is applied to the rotor 4 to move the lock pin 13 to the advance limiting groove 17.
It is possible to prevent the fluttering of the rotor 4 due to the torque fluctuation of the camshaft 3 by pressing the rotor 4 against the end of the rotor 4.

In this case, for example, the oil temperature of the hydraulic circuit is detected by the oil temperature sensor 22 (see FIG. 2), and when the detected temperature is equal to or higher than the preset temperature, the rotor 4 is activated by the first hydraulic control valve 5. A retard angle pressure is applied to. In addition to the oil temperature, the first hydraulic control valve 5 may be controlled based on the temperature of the engine cooling water.

[Brief description of drawings]

FIG. 1 is an axial plan view showing an internal structure of a valve timing adjusting device.

FIG. 2 is a system diagram showing a valve timing adjusting device and a hydraulic circuit.

FIG. 3 is a schematic view showing a configuration of a retard angle limiting pin and a lock pin.

FIG. 4 is an operation explanatory diagram during normal operation.

FIG. 5 is an operation explanatory view at the time of normal stop.

FIG. 6 is an operation explanatory diagram when the vehicle is stopped on the advance side and the retard side.

FIG. 7 is a graph showing the behavior of the rotor associated with the advance control at the time of starting (conventional VVT).

FIG. 8 is a graph showing the behavior of the rotor associated with the advance angle control at the time of starting (VVT of the present invention).

[Explanation of symbols]

1 VVT (valve timing adjustment device) 2 Housing member 3 cam shaft (cam shaft) 4 rotor 5 First hydraulic control valve 6 Second hydraulic control valve 7 retard room 8 Advance room 10 vanes 13 Lock pin 15 spring 17 Lead angle limiting groove (guide groove) 18 Lock recess

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 41/08 320 F02D 41/08 320 F term (reference) 3G018 AB02 BA09 BA10 CA20 DA22 DA70 EA02 EA12 EA17 EA21 FA01 FA07 GA11 3G092 AA11 DA09 DG05 EA11 EA29 EC01 FA32 GA01 GA04 GA10 HE01Z HE08Z 3G301 HA19 JA03 KA01 KA07 KA28 LA07 PE01Z PE08Z PE10A

Claims (4)

[Claims] 1. A housing member, which is rotated by transmitting a rotational force from a drive shaft of an internal combustion engine, is fixed to a cam shaft of the internal combustion engine, and is provided so as to be rotatable relative to the housing member within a predetermined angle range. A rotor, a hydraulic chamber formed inside the housing member between the rotor and the rotor, the rotor is provided integrally with the rotor, and is housed in the hydraulic chamber to form the advance chamber and the retard chamber. A vane that divides the vane into two parts, a first hydraulic control valve that controls the hydraulic pressure of the advance chamber and the retard chamber, and an engine between the most advanced phase and the most retarded phase of the rotor with respect to the housing member. An optimum lock phase for starting is set, and a lock recessed portion provided in the housing member corresponding to this lock phase, and a retractably incorporated into the vane, the head of the body protrudes from the vane. Previous A lock pin for restraining the rotor to the lock phase by fitting the locking recess, the second for controlling the hydraulic pressure for operating the locking pin
Of the hydraulic control valve, and guides the head of the lock pin so that the head of the lock pin can move in a state of protruding from the vane when advancing the rotor toward the lock phase. A valve timing adjusting device having a guide groove, wherein the guide groove has a retard side end portion set to a startable phase capable of starting an engine between the lock phase and the most retarded phase. The second hydraulic control valve controls the hydraulic pressure for the lock pin so that the head of the lock pin projects from the vane and fits in the guide groove when idling. . 2. The valve timing adjusting device according to claim 1, wherein the first hydraulic control valve presses the lock pin against an end portion of the guide groove set to the startable phase during idling. Therefore, the valve timing adjusting device is characterized in that a retard angle pressure is applied to the rotor. 3. The valve timing adjusting device according to claim 2, wherein the first hydraulic control valve applies a retard angle pressure to the rotor when an oil temperature during idling or an engine cooling water temperature is equal to or higher than a predetermined temperature. A valve timing adjusting device characterized by being provided. 4. The valve timing adjusting device according to claim 1, wherein the lock pin is biased by a spring in a direction to be pushed out from the vane, and the lock pin is operated by the second hydraulic control valve. The supplied hydraulic pressure acts against the biasing force of the spring to push the lock pin back into the vane, and the second hydraulic control valve stops the supply of hydraulic pressure to the lock pin during idling. A valve timing adjusting device characterized in that