JP2854314B2 - Engine valve timing control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for an engine, and more particularly to a device capable of adjusting a switching speed of a valve timing change.

(Prior art)

Conventionally, as an engine with a supercharger, for example, JP-A-61-18
As disclosed in JP-A-7543 and JP-A-61-197720, a mechanical supercharger is provided in an intake passage, and this supercharger is connected to an engine output shaft via a clutch to provide a high-speed high-load region. In the supercharging region, the engine is supercharged by operating the supercharger by connecting the clutch, and its output is increased. And reduce fuel consumption. Further, a timing change device that is driven by a step motor and varies intake / exhaust timing is provided in the valve train of the engine so that the intake / exhaust overlap period can be varied. The amount of overlap between the intake and exhaust gas is made larger than that, and the scavenging of the burned gas in the combustion chamber is promoted to suppress the occurrence of noshing.

On the other hand, Japanese Patent Application Laid-Open No. 62-191636 discloses a valve timing changing device for changing the relative phase between a camshaft and a rotation transmitting member (gear or pulley) provided on the camshaft by a hydraulic actuator. An engine valve timing control device is described in which an electromagnetic on-off valve is provided in a relief passage for relieving pressure oil supplied to an actuator, and valve timing is switched via a hydraulic actuator by controlling opening and closing of the electromagnetic on-off valve. ing.

[Problems to be solved by the invention]

If the intake / exhaust timing of the engine is changed to change the intake / exhaust overlap amount, the characteristics of the engine will fluctuate greatly.However, the conventional valve timing control device adjusts the switching speed when changing and controlling the valve timing. Not to be able to do it. Therefore, the valve timing is switched so that the intake / exhaust overlap amount increases at the same switching speed regardless of whether the vehicle accelerates rapidly or slowly from the low-speed low-load state.

When the switching speed of the valve timing is set to be small, torque shock when switching the valve timing during acceleration / deceleration can be prevented, but the valve timing switching is delayed during rapid acceleration, resulting in lack of responsiveness.

On the other hand, when the switching speed is set to be large, not only is the torque shock increased when switching the valve timing during acceleration / deceleration, but also the torque characteristics of the engine fluctuate rapidly during slow acceleration.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine valve timing control device capable of adjusting a switching speed of a valve timing change.

[Means for solving the problem]

The engine valve timing control device according to claim 1,
With a valve timing change device having a hydraulic actuator that changes the intake timing or the exhaust timing,
In an engine valve timing control device that changes and controls the valve timing according to the operating state of the engine,
Switching speed adjusting means for rapidly changing and controlling the valve timing at the time of rapid acceleration, and gradually changing and controlling the valve timing at the time of gentle acceleration is provided, and the switching speed adjusting means is provided with a supply oil passage for supplying oil pressure to the hydraulic actuator. An oil passage area changing means for changing the area is provided so that the supply oil passage area is increased during rapid acceleration and the supply oil passage area is decreased during slow acceleration.

The engine valve timing control device according to claim 2 is
In the invention of claim 1, two oil passages are provided in at least a part of the supply oil passage, and the oil passage area changing means opens two oil passages during rapid acceleration and only one oil passage during slow acceleration. It is characterized by comprising switching means for opening.

The engine valve timing control device according to claim 3 is
An engine valve timing control device that includes a valve timing changing device that changes an intake timing or an exhaust timing, and that controls a valve timing according to an operating state of an engine, wherein the valve timing changing device is provided on a camshaft and a camshaft. A hydraulic actuator that changes the relative phase with the rotation transmitting member, a supply passage that supplies pressure oil to the hydraulic actuator, a relief passage that reliefs the pressure oil in the supply passage, and an on-off valve that opens and closes the relief passage. And a passage area changing means for increasing the supply passage area during slow deceleration and decreasing the supply passage area during rapid deceleration.

The engine valve timing control device according to claim 4 is:
An engine valve timing control device that includes a valve timing changing device that changes an intake timing or an exhaust timing and that controls a valve timing according to an operating state of an engine. Switching speed adjusting means for gradually changing and controlling the valve timing during deceleration is provided.

The engine valve timing control device according to claim 5,
According to a fourth aspect of the present invention, the switching speed adjusting means is configured to determine a rapid deceleration and a slow deceleration based on the operating angular velocity of the throttle valve.

[Action]

According to the first aspect of the present invention, a switching speed adjusting means having a hydraulic actuator for controlling suddenly changing the valve timing at the time of rapid acceleration and gradually controlling the valve timing at the time of gentle acceleration is provided. The valve timing is rapidly changed and controlled, so that the valve timing can be switched to a valve timing suitable for the operating state without a response delay of the valve timing switching, and the valve timing is gradually changed and controlled at the time of gentle acceleration, whereby the valve timing is changed. Therefore, it is possible to prevent a sudden change in torque shock and engine characteristics.

The switching speed adjusting means has an oil passage area changing means for changing an area of a supply oil passage for supplying oil pressure to the hydraulic actuator, and at the time of rapid acceleration, the supply oil passage area is enlarged to control sudden change of valve timing. At the time of gentle acceleration, the supply oil passage area is reduced and the valve timing is gradually changed and controlled.

According to the second aspect of the invention, the same operation as the first aspect is achieved, but two oil paths are provided in at least a part of the supply oil path, and the oil path area changing means connects the two oil paths at the time of rapid acceleration. Since the switching means is configured to be opened and only one oil path is opened at the time of gentle acceleration, the configuration of the oil path area changing means is simplified.

In the invention of claim 3, the valve timing changing device includes a hydraulic actuator for changing the valve timing, a supply passage for supplying pressure oil to the actuator, a relief passage for relieving the pressure oil in the supply passage,
It is a hydraulic type provided with an on-off valve for opening and closing a relief passage. The switching speed of the valve timing switching is determined according to the supply flow rate when supplying the hydraulic pressure from the supply passage.

Since the supply passage is switched by the passage changing means to be large during slow deceleration and small during sudden deceleration, the valve timing is switched gradually during slow deceleration and suddenly during rapid deceleration. As a result, torque shock when switching the valve timing during slow deceleration is prevented, and a response delay in switching the valve timing during rapid deceleration does not occur.

According to the fourth aspect of the present invention, the valve speed is suddenly changed and controlled at the time of rapid deceleration by the switching speed adjusting means, so that there is no response delay in switching the valve timing at the time of rapid deceleration, similarly to the third aspect. Further, since the valve speed is gradually changed and controlled at the time of slow deceleration by the switching speed adjusting means, a torque shock at the time of switching the valve timing at the time of slow deceleration can be prevented.

According to the fifth aspect of the present invention, the same operation as in the fourth aspect is achieved, but the switching speed adjusting means determines the rapid deceleration and the slow deceleration based on the operating angular velocity of the throttle valve. Responsiveness of the deceleration determination is increased.

〔The invention's effect〕

According to the first aspect of the present invention, as described in the above section, by providing the switching speed adjusting means, it is possible to enhance the response of the valve timing switching at the time of rapid acceleration to enhance the acceleration response. In addition, at the time of gentle acceleration, it is possible to prevent a torque shock and a sudden change in engine characteristics accompanying the switching of the valve timing.

The switching speed adjusting means has an oil passage area changing means for changing an area of a supply oil passage for supplying oil pressure to the hydraulic actuator, and at the time of rapid acceleration, the supply oil passage area is enlarged to control sudden change of valve timing. At the time of gentle acceleration, the supply oil passage area is reduced and the valve timing is gradually changed and controlled.

According to the second aspect of the present invention, the same effect as that of the first aspect is obtained, but two oil paths are provided in at least a part of the supply oil path, and the oil path area changing means performs two oil paths at the time of rapid acceleration. And the switching means for opening only one oil passage at the time of gentle acceleration, the structure of the oil passage area changing means is simplified.

According to the third aspect of the present invention, as described in the above section, by providing the passage changing means, it is possible to prevent torque shock when switching valve timing during slow deceleration, and to prevent valve shock during sudden deceleration. Responsiveness of timing switching can be enhanced to enhance deceleration responsiveness.

According to the invention of claim 4, the switching speed adjusting means
Since the valve timing is suddenly changed and controlled at the time of sudden deceleration, a response delay of the valve timing switching at the time of sudden deceleration does not occur. Further, since the valve speed is gradually changed and controlled at the time of slow deceleration by the switching speed adjusting means, a torque shock at the time of switching the valve timing at the time of slow deceleration can be prevented.

According to the fifth aspect of the present invention, the same effect as in the fourth aspect is obtained, but the switching speed adjusting means determines the rapid deceleration and the slow deceleration based on the operating angular speed of the throttle valve.
Responsiveness of determination of sudden deceleration and slow deceleration is improved.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The present embodiment is an example in which the present invention is applied to an engine with a supercharger of a two-cylinder intake two-valve exhaust two-valve type for an automobile.

As shown in FIG. 1, each of the four cylinders 1 of the engine E has an intake port 2 opened and closed by an intake valve 2a and an exhaust valve.
An exhaust port 3 which is opened and closed by 3a is provided, and eight intake valves 2a are driven by an intake camshaft 4, and eight exhaust valves are provided.
3a is driven by the exhaust camshaft 5. The camshafts 4 and 5 are linked to a crankshaft pulley 6 as described later.

In the intake passage 10 of the engine E, an air cleaner 11, an air flow meter 12, a throttle valve 13, a mechanical supercharger 14, and a surge tank 16 are provided in this order from the upstream side.
Are connected to the intake port 2 at each branch intake pipe 17. Further, an injector 15 for injecting fuel toward each intake port 2 is mounted on the branch intake pipe 17. The throttle valve 13 is connected to an accelerator pedal, and the throttle valve 13 is provided with a throttle opening sensor 18 for electrically detecting the opening thereof and an idle switch (not shown) which is closed when the throttle valve 13 is fully closed. I have. A bypass passage 19 that bypasses the supercharger 14 is provided.
The bypass valve 20 is driven by an actuator 21 to which a boost negative pressure is introduced via a negative pressure introducing passage 22.
The valve opening characteristics of the bypass valve 20 are as shown in FIG.

An electromagnetic clutch 25 is interposed on the input shaft 14a of the supercharger 14, and a pulley 26 of the input shaft 14a is linked to the crankshaft pulley 6 by a belt or a chain. A control unit 27 for controlling the electromagnetic clutch 25 and an overlap switching solenoid 31 of a valve timing changing mechanism 30 for switching the intake / exhaust overlap amount to be described later between magnitude and magnitude, and an electromagnetic opening / closing valve 58 is provided. Is a signal from the air flow meter 12, a signal from the throttle opening sensor 18, a signal from the idle switch, an engine speed signal N from the distributor, and the like.

Next, the valve timing changing mechanism 30 will be described with reference to FIGS. In the valve gear of the engine E, a cylindrical spacer 32 is fixed to an end of the exhaust camshaft 5, and a driving pulley 7 is mounted outside the spacer 32. The pulley 7 is in sliding contact with the outer periphery of the distal end of the spacer 32 at the distal end of the boss portion 34, and the proximal end side of the boss portion 34 is fixed to a cylindrical connecting member 35 rotatably mounted on the exhaust camshaft 5. I have. The connecting member 35 is rotatably supported by a bearing portion 36A of the cylinder head 36, and a first gear 8 is spline-connected to the other end of the connecting member 35 and fixed by a lock nut 37. The first gear 8 is meshed with a second gear 9 fixed to the tip of the intake camshaft 4. An annular piston 38 is incorporated between the spacer 32 and the boss 34 of the pulley 7. The piston 38 has a structure divided into two parts in the axial direction,
Both divided parts are provided with a plurality of pins 39 arranged at equal intervals in the circumferential direction.
Are fixed to each other. Helical splines 40 and 41 in opposite directions are formed inside and outside the piston 38. A helical spline 42 is formed on the outer periphery of the spacer 32 with respect to the spline 40 inside the piston 38, and a helical spline 43 is formed on the inner periphery of the boss portion 34 of the pulley 7 with respect to the helical spline 41 on the outer periphery of the piston 38. . The piston 38 is urged toward the distal end by a spring 44 mounted between the piston 38 and the end face of the connecting member 35.

The exhaust camshaft 5 has an oil passage along the axis.
45 are formed. The cylindrical spacer 32 is fixed to the exhaust camshaft 5 by a fixing bolt 47 via a stopper member 46. The fixing bolt 47 has an axial through hole 48 communicating with the oil passage 45.

At the tip of the boss portion 34 of the pulley 7, a pressure chamber 49 for guiding the oil pressure from the oil passage 45 is provided facing the head of the piston 38. The other end of the exhaust camshaft 5 is rotatably supported by a bearing portion 36B of the cylinder head 36, and the end of the support hole 50 is closed by a plug 51.

As shown in FIGS. 2 and 3, in order to supply the oil pressure to the oil passage 45 or to discharge the oil pressure from the oil passage 45, the cylinder head 36 is switched over to the cylinder head 36 at the side of the pivot hole 50. Switching valve 52 operated by solenoid 31
When the solenoid 31 is OFF as shown in FIG. 3, the switching valve 52 is in the discharge position, the oil passage 45 is connected to the drain passage 53, and when the solenoid 31 is ON, the switching valve is
Reference numeral 52 denotes a supply position, in which the oil passage 45 is connected to a hydraulic supply path 54 (oil gallery), and pressurized oil is supplied to the hydraulic supply path 54 from a lubricating oil pump driven by a crankshaft.

That is, when the switching solenoid 31 is turned on to switch the switching valve 52 to the supply position, the oil pressure is supplied to the pressure chamber 49 through the oil passage 45 to compress the spring 44 and move the piston 38 in the axial direction. As a result, one of the spacer 32 and the pulley 7, which is fitted to the splines 40 and 41 formed in the inner and outer circumferences of the piston 38 in the opposite directions, rotates relatively to the other. Thus, the relative phase between the exhaust camshaft 5 integrated with the spacer 32 and the pulley 7 changes.

A small-flow oil passage 56 provided with an orifice 55 in the hydraulic supply passage 54 on the upstream side of the switching valve 52, and this small-flow oil passage
A large flow oil passage 57 having a large oil passage cross-sectional area bypassing 56 is provided, and the large flow oil passage 57 is provided with an electromagnetic on-off valve 58 for opening and closing this oil passage, and the electromagnetic on-off valve 58 is controlled by the control unit 27. Controlled. The electromagnetic on-off valve 58 is kept open only during rapid acceleration, as described later, and is kept closed otherwise.

As described later, in the large overlap region, the oil passage
Since the hydraulic pressure is supplied to 45, the exhaust valve closing timing shifts to the delay side as shown in FIG. 4, and the intake valve opening timing does not change, so that the amount of overlap between intake and exhaust increases. On the other hand, in the overlap small area, the oil pressure of the oil passage 45 is discharged,
Since the piston 38 is returned by the elastic force of the spring 44, the overlap amount is reduced.

The control unit 27 has a general configuration including an A / D converter, a waveform shaping circuit, an input / output interface, a microcomputer, a plurality of drive circuits, and the like. A program that controls the electromagnetic clutch 25 according to the operating state
PA, an intake / exhaust overlap amount control program PB for switching the intake / exhaust overlap amount to a large or small value via the switching solenoid 31 according to the operating state, the intake / exhaust overlap amount from "large" to "small" and vice versa A switching speed adjustment program PC that controls the switching speed when switching to the electromagnetic opening / closing valve 58 so as to be adapted to rapid acceleration / deceleration, and other programs such as ignition timing control and fuel injection control are input and stored in advance. .

FIG. 5 is an explanatory diagram of various areas included in the programs PA, PB, and PC in a table and a map. In a low-speed and low-load area A inside the curve a, the switching solenoid 31 is held OFF and the oil is stored. In the overlap small area where the hydraulic pressure of the passage 45 is removed and the intake / exhaust overlap amount is kept “small”, the areas B and C outside the curve a maintain the switching solenoid 31 ON and supply the oil pressure to the oil passage 45. A large overlap region where the intake / exhaust overlap amount is maintained at “large”, and a region C outside the broken line b is an electromagnetic clutch ON region (supercharge region) in which the supercharger 14 is operated to perform supercharging. Note that the bypass valve 20 is fully opened in a region on the low load side from the straight line c, and the opening degree of the bypass valve 20 decreases in accordance with the shift to the high load side from the straight line c. It is closed (see FIG. 6).

Next, an outline of a routine of the control program PB / PC will be described with reference to FIGS. In the figure, Si (i
= 1, 2, 3,...) Indicate the respective steps. These routines are executed every time a predetermined time interval of an interrupt process or every input of a crank angle signal output from a crank angle sensor (not shown) for each rotation of the crankshaft. Executed in interrupt processing.

FIG. 7 shows that the intake / exhaust overlap amount is “small” when the operation state is in the small overlap region, and the intake / exhaust overlap amount is “large” when the operation state is in the large overlap region.
This is a routine for controlling the intake / exhaust overlap amount via the valve timing changing mechanism 30 including the switching solenoid 31. After the control is started, the engine speed N and the intake air amount Q are read (S1), and the operation is started. It is determined whether the state is a large overlap area (areas B and C in FIG. 5) (S2), and Yes
In this case, the switching solenoid 31 is turned ON (S3), hydraulic pressure is supplied to the oil passage 45, and the intake / exhaust overlap amount is switched to "large" (shown by a dotted line in FIG. 4) by the valve timing changing mechanism 30. . On the other hand, when the overlap area is not the large overlap area, the switching solenoid 31 is controlled to be turned off (S4), the oil pressure in the oil passage 45 is discharged, and the intake / exhaust overlap amount is “small” by the valve timing changing mechanism 30.
Is switched to After the execution of the above routine, the process returns to the main routine.

FIG. 8 is a switching speed adjustment control routine for changing the switching speed when changing the intake / exhaust overlap amount so that the switching speed becomes sharp at the time of rapid acceleration and gradually at the time of gentle acceleration. The throttle opening .theta. From the sensor 18 is read (S10), and the angular velocity A of the throttle valve 13 is determined based on the past throttle opening .theta. Data and the current throttle opening .theta. Data stored in the RAM memory. There is calculated (S11), then the angular velocity a is determined whether or not a predetermined value a ₀ is greater than whether that rapid acceleration state (S12), when the rapid acceleration state solenoid valve 58 is controlled to the valve opening ( S13),
When the vehicle is not in the rapid acceleration state (including the gentle acceleration state), the electromagnetic on-off valve 58 is controlled to close (S14), and thereafter, returns to the main routine.

Next, the operation of the engine valve timing control device will be described.

Since the intake / exhaust overlap amount is maintained at “large” also in the medium speed / medium load region B inside the supercharging region C shown in FIG. It flows back to the intake port 2 due to negative pressure and mixes with fresh air.
The same fuel economy reduction effect as when exhaust gas recirculation is performed can be obtained.

In the supercharging region C, the intake / exhaust overlap amount is “large”
, The high-temperature burned gas is scavenged to reliably prevent knocking.

On the other hand, as described by the flow chart of Figure 8, since the angular velocity A is the rapid acceleration time greater than the predetermined value A ₀ opens the solenoid valve 58, the high flow fluid passage 57 in addition to the small flow rate oil passage 56 Pressure oil is supplied to the pressure chamber 49 therethrough. Therefore,
The switching speed when the intake / exhaust overlap amount is switched from "small" to "large" in response to sudden acceleration increases, and the switching is performed in a short time. Since the valve timing of the exhaust valve 3 is switched without a response delay in this manner, there is no fear of knocking occurring immediately after sudden acceleration, and the acceleration response is also improved.

On the other hand, since the solenoid on-off valve 58 is kept closed at times other than sudden acceleration, the orifice
Pressure oil is supplied to the pressure chamber 49 through 55. Accordingly, the switching speed when the intake / exhaust overlap amount is switched from “small” to “large” and vice versa is reduced. If the valve timing is suddenly switched such as during slow acceleration and the characteristics of the engine change suddenly, problems such as torque shock and a sudden change in vehicle speed may occur, but the valve gradually slows during slow acceleration or deceleration as described above. Since the timing is switched, the above problem does not occur.

In the above-described embodiment, the valve timing changing mechanism 30 is incorporated in the exhaust camshaft 5, but this is incorporated in the intake camshaft 4 to fix the exhaust valve timing and change the intake valve timing. The lap amount may be changed.

<Another Embodiment> See FIGS. 9 to 11 The engine valve timing control device of this embodiment
The following changes have been made to the supply system for supplying pressure oil to the valve timing change mechanism 30 and the discharge system for discharging pressure oil, and the other points are the same as in the previous embodiment, and are the same or the same. Components having similar functions are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 9, the switching solenoid 31 and the switching valve
The relief valve body 61 facing the end of the oil passage 45 on the end side of the exhaust camshaft 5 with the 52 and the plug 51 removed, and a relief solenoid 62 for controlling opening and closing of the relief valve body 61
Is provided. Relief valve
When the valve 60 is opened, part of the pressure oil in the oil passage 45
Since the fluid flows from the end of 50 to the drain passage 53, the hydraulic pressure of the pressure chamber 49 decreases.

The hydraulic supply passage 54 branches into a small flow oil passage 56 having an orifice 55 and a large flow oil passage 57 having a large passage cross-sectional area in the pivot portion 36A, and the small flow oil passage 56 is formed by an annular groove 56b and a through hole 56a. The large flow oil passage 57 communicates with the oil passage 45 through an annular groove 57b and a through hole 57a, and the large flow oil passage 57 is provided with an electromagnetic on-off valve 58 that can open and close the passage. The relief solenoid 62 and the solenoid on-off valve 58 are connected to the control unit 27.
Is controlled by

During operation of the engine E, pressurized oil is supplied to the oil supply passage 54 from an oil gallery of lubricating oil. When the relief valve 60 is closed, the oil pressure in the oil passage 45 and the pressure chamber 49 increases, and the piston 38 Is driven, the intake / exhaust overlap amount is switched to “large”, and when the relief valve 60 is opened,
The oil pressure in the oil passage 45 and the pressure chamber 49 decreases, and the intake / exhaust overlap amount is switched to “small”. FIG. 10 corresponds to the routine of FIG. 7 and will be described.

After the start of the control, the engine speed N and the intake air amount Q are read (S20), and it is then determined whether or not the operation state is in the large overlap region (S21). If Yes, the relief solenoid 62 is brought to the closed position. Controlled (S22), resulting in a pressure chamber 49
, The piston 38 moves against the spring 44, and the intake / exhaust overlap amount is switched to “large”.
On the other hand, when the overlap area is not the large area, the relief solenoid 62 is controlled to the open position (S23). As a result, the oil pressure in the pressure chamber 49 decreases, the piston 38 is pushed by the spring 44, and the intake / exhaust overlap amount becomes " Is switched to "Small".
FIG. 11 corresponds to the routine of FIG. 8 and will be described.

After the control starts, the throttle opening θ is read (S30),
Next, the angular velocity A = dθ / dt is calculated in the same manner as in the above embodiment (S31). Next, it is determined whether or not the angular velocity A is A> 0, that is, whether or not the vehicle is accelerating (S32). A
There predetermined value a ₀ is greater than whether That rapid acceleration whether the determination (S33), the solenoid valve 58 is controlled to open when the A> a ₀ (S34). On the other hand, when the vehicle is accelerating but not suddenly accelerating, the electromagnetic on-off valve 58 is controlled to close (S37).

In contrast, the result of the determination in S32, when it is not in the acceleration state, A <0 whether words is determined whether deceleration state (S35), when the Yes is | A |> or a ₀ or whether that is rapid deceleration Is determined (S36), and when the vehicle is suddenly decelerated, the solenoid on-off valve 58
Is controlled to close (S37), and when not suddenly decelerating, the electromagnetic on-off valve 58 is controlled to open (S34). Further, when the result of the determination in S35 is No, that is, when it is in a steady state, the solenoid on-off valve 58
Is not operated, the current position is maintained, and the process returns to the main routine after the end of S30 to S37.

In the valve timing control device according to this embodiment, since the electromagnetic on-off valve 58 is opened during rapid acceleration as described above, the supply flow rate of the pressure oil increases, and the intake / exhaust overlap amount “small” to “large” Is rapidly performed, and the electromagnetic switching valve 58 is closed during slow acceleration, so that the above-described switching is performed gradually.

Also, at the time of sudden deceleration, since the electromagnetic on-off valve 58 is closed,
The switching of the intake / exhaust overlap amount from “large” to “small” is rapidly performed, and the above-described switching is gradually performed since the electromagnetic opening / closing valve 58 is opened during slow deceleration.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of the present invention. FIG. 1 is a structural view of a main part of a supercharged engine, FIG. 2 is a sectional view of a valve timing changing mechanism, FIG. 4 is an explanatory diagram of valve timing, FIG. 5 is an explanatory diagram of a large overlap region and a small overlap region, FIG. 6 is a characteristic diagram of an opening degree of a bypass valve, and FIG. 7 is a routine of intake and exhaust overlap amount control. FIG. 8 is a flowchart of a switching speed adjustment control routine, and FIGS. 9, 10, and 11 relate to another embodiment. FIG. 9 is a diagram corresponding to FIG.
Fig. 11 is a flowchart of a routine of intake / exhaust overlap amount control, and Fig. 11 is a flowchart of a routine of switching speed adjustment control. E: engine, 4: intake camshaft, 5: exhaust camshaft, 12: air flow meter, 27: control unit, 30: valve timing change mechanism, 31: switching solenoid, 55 ... Orifice, 56 ……
Small flow oil passage, 57 ... High flow oil passage, 58 ... Solenoid on-off valve, 60
… Relief valve, 61… Relief valve body, 62… Relief solenoid.

Continuation of the front page (56) References JP-A-54-117813 (JP, A) JP-A-55-87811 (JP, A) JP-A-59-119007 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) F01L 1/34 F01L 13/00

Claims (5)

(57) [Claims] 1. A valve timing control device for an engine, comprising: a valve timing changing device having a hydraulic actuator for changing an intake timing or an exhaust timing, wherein the valve timing is controlled in accordance with an operation state of the engine. Switching speed adjusting means for rapidly changing and controlling the valve timing at the time of gentle acceleration, wherein the switching speed adjusting means changes the area of a supply oil passage for supplying oil pressure to the hydraulic actuator. An engine valve timing control device comprising a road area changing means, wherein the supply oil path area is increased during rapid acceleration and the supply oil path area is reduced during slow acceleration. 2. An oil passage area changing means, comprising: two oil passages provided at least in a part of the supply oil passage;
2. A switching means for opening one oil passage and opening only one oil passage during gentle acceleration.
3. The valve timing control device for an engine according to claim 1. 3. A valve timing control device for an engine, comprising: a valve timing changing device for changing an intake timing or an exhaust timing, wherein the valve timing changing device controls the valve timing in accordance with an operation state of the engine. A hydraulic actuator for changing the relative phase between the hydraulic actuator and a rotation transmitting member provided on the camshaft, a supply passage for supplying pressure oil to the hydraulic actuator, a relief passage for relieving the pressure oil in the supply passage, and a relief passage. A valve timing control device for an engine, comprising: an on-off valve that opens and closes, and a passage area changing unit that increases the supply passage area during slow deceleration and reduces the supply passage area during rapid deceleration. 4. A valve timing control device for an engine, comprising: a valve timing changing device for changing an intake timing or an exhaust timing, wherein the valve timing is changed according to an operation state of the engine. A valve timing control device for an engine, comprising switching speed adjusting means for controlling and gradually changing the valve timing during slow deceleration. 5. The valve timing of an engine according to claim 4, wherein said switching speed adjusting means is configured to judge a rapid deceleration and a slow deceleration based on an operating angular speed of a throttle valve. Control device.