JP2824583B2 - Engine valve timing control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine valve timing control device that changes valve timing by supplying oil pressure to a variable valve timing mechanism mounted on a camshaft of an engine. Things.

(Prior Art) Conventionally, a hydraulically driven variable valve timing mechanism is mounted on a camshaft of an engine, and a passage for introducing engine lubricating oil through a camshaft bearing is formed in the variable valve timing mechanism. A technique of operating the valve timing variable mechanism by applying a hydraulic pressure to the variable valve timing mechanism by a hydraulic control means during a specific operation to change the valve timing is known as disclosed in, for example, JP-A-62-191636. .

As the variable valve timing mechanism, various mechanisms have been proposed in addition to those that change the relative phase between a cam pulley and a camshaft. A valve that changes the valve timing by switching between a hydraulic supply state and a non-supply state by interposing a switching valve in the middle of the passage, or releasing the hydraulic pressure to the drain side when the hydraulic pressure is always in the supply state and not operating Then, a valve timing is changed.

(Problems to be Solved by the Invention) However, in the above-described valve timing control device, when the hydraulic pressure is not supplied to the variable valve timing mechanism due to the failure of the hydraulic control means or the like, the bearing portion of the camshaft. May cause poor lubrication, which may cause a problem in engine durability.

That is, a part of the engine lubricating oil is supplied to the variable valve timing mechanism mounted on the camshaft from the engine body side via the bearing portion of the camshaft,
The operation of the variable valve timing mechanism is operated, and lubrication of the bearing portion of the camshaft is performed by a part of oil for supplying hydraulic pressure to the variable valve timing mechanism. A malfunction such as disconnection, disconnection, or poor contact of the harness coupler connected to drive the solenoid valve interposed in the hydraulic pressure supply passage for the variable valve timing mechanism occurs, and the oil for the variable valve timing mechanism increases. When the supply of oil becomes impossible, the supply of oil to the bearing portion of the camshaft is stopped, lubrication is insufficient, and high-speed rotation is performed. Camshaft seizure may occur.

In view of the above circumstances, the present invention suppresses the occurrence of a problem caused by insufficient lubrication of a cam shaft bearing when a failure occurs in which hydraulic pressure cannot be applied to a variable valve timing mechanism. It is an object of the present invention to provide an engine valve timing control device.

(Means for Solving the Problems) In order to achieve the above object, a valve timing control device according to the present invention comprises a variable valve timing mechanism A mounted on a camshaft C of an engine E as shown in FIG. Hydraulic control means for introducing an engine lubricating oil through a camshaft bearing portion B and applying a hydraulic pressure to the variable valve timing mechanism A during a specific operation to change the valve timing and lubricate the camshaft bearing portion D, and a failure detecting means F for detecting a failure state in which the hydraulic pressure by the hydraulic pressure control means D cannot act on the variable valve timing mechanism A. The failure detecting means F receives a signal from the failure detecting means F to detect the occurrence of a failure. At the time, a failure control means G for limiting the maximum number of revolutions of the engine to a low level is provided.

It is preferable that the specific operation for supplying the hydraulic pressure to the variable valve timing mechanism is a high rotation time. Further, it is preferable that the failure time control means changes the shift point of the gear position of the automatic transmission to a low rotation side or stops fuel supply to the engine to suppress the maximum rotation number of the engine low. is there. On the other hand, the camshaft bearing is lubricated by a part of engine lubricating oil supplied to the variable valve timing mechanism.

(Operation) In the above-described valve timing control device, during normal operation, hydraulic pressure is supplied to the variable valve timing mechanism by the hydraulic control means in a specific operation state to change the valve timing, while the hydraulic control means performs the above operation. When the failure detecting means detects the occurrence of a failure state in which the hydraulic pressure cannot be applied to the variable valve timing mechanism, the failure-time control means is operated, for example, by stopping the fuel supply, shifting control of the automatic transmission, etc. Is controlled to prevent seizure or the like from occurring in the bearing portion of the camshaft even if the supply of the engine lubricating oil becomes insufficient.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Second
FIG. 1 shows a schematic configuration of an engine including a valve timing control device according to one embodiment.

In a cylinder 1 a of the engine 1, an intake port 5 opened and closed by an intake valve 4 and an exhaust port 7 opened and closed by an exhaust valve 6 are opened in a combustion chamber 3 formed above the piston 2. The exhaust port 7 is connected to the exhaust port 9.

An overhead intake-side camshaft 11 for opening and closing the intake valve 4 of each cylinder 1a is provided, and an overhead exhaust-side camshaft 12 for opening and closing the exhaust valve 6 of each cylinder 1a. . Both camshafts 11, 12
Are rotationally driven in synchronization with the rotation of the engine output shaft 15 via a timing belt 14 by a synchronous drive mechanism 13 installed at each end.

On the other hand, in the intake passage 8 communicating with the intake port 5,
An air cleaner 18, an intake air sensor 19, and a throttle valve 20 are interposed from the upstream side, and a mechanical supercharger 21 is disposed downstream of the throttle valve 20. Further, in the intake passage 8 on the downstream side of the supercharger 21, the cylinder 1a
An injector 23 is formed in an independent intake passage 8a connected to the intake passage 8 and supplies fuel to the independent intake passage 8a.

Further, the supercharger 21 is bypassed to bypass the supercharger 21.
A supercharging bypass valve 25 is interposed in the supercharging bypass passage 24. Supercharged bypass valve 25
Opens according to the intake pressure downstream of the throttle valve 20,
Supercharging bypass passage when supercharging by turbocharger 21 is insufficient
At the same time as supplying the intake air by 24, it opens when the supercharging pressure becomes high and relieves the supercharging air to regulate the upper limit of the supercharging pressure and reduce the driving load.

Further, the exhaust side camshaft 12 with respect to the exhaust valve 6
Is provided with a variable valve timing mechanism 27 that changes the opening / closing timing to change the period of overlap with the intake valve 4. Although the details of the variable valve timing mechanism 27 will be described later with reference to FIG. 4, it is of a hydraulically operated type, in which engine lubricating oil from an oil pump (not shown) of the engine is supplied through an oil supply passage 28. A passage switching mechanism including a three-way solenoid valve 29 is interposed in the middle of the supply passage 28 to switch between hydraulic pressure supply and return opening.

As shown in FIG. 3, a specific structural example of the three-way solenoid valve 29 is such that a spool valve 32 is inserted into a cylinder 31, a return spring 33 is compressed at one end, and a rod 34a of a driving solenoid 34 is mounted at the other end. Abuts the spool valve 3
According to the movement of 2, the communication with the return b port that opens the port a communicating with the oil supply passage 28 to the variable valve timing mechanism 27 into the cylinder head or the communication with the port c that communicates with the on-pump for engine lubrication is switched. It is configured. The d port is opened to the return side to allow the spool valve 32 to move.
The solid line indicates the off state and the chain line indicates the on state. In the off state, the port a and the b port communicate with each other, and no oil is supplied to the variable valve timing mechanism 27. Due to the movement, the port a and the port c communicate with each other, the oil from the oil pump is supplied to the variable valve timing mechanism 27, and a predetermined hydraulic pressure is introduced.

Then, a drive signal is output from the engine controller 36 to the drive solenoid 34 of the three-way solenoid valve 29 according to the operation state, and hydraulic pressure is introduced to the valve timing variable mechanism 27 during a specific operation (high load and high rotation range). To extend the valve overlap period.

The engine controller 36 outputs a fuel injection signal for adjusting the fuel supply amount to the injector 23 of the intake passage 8 and an ignition signal for adjusting the ignition timing to the ignition plug 37 of the cylinder 1a. The engine controller 36 receives an intake air amount signal from an intake air amount sensor 19 and a signal from a throttle sensor 38 for detecting a throttle opening in order to detect an operation state. A hydraulic signal from a hydraulic sensor 39 for detecting a failure state of supply of hydraulic pressure to the engine, a signal from a rotation sensor 40 for detecting engine rotation, and the like are input.

Further, the engine controller 36 outputs a correction signal such as a fuel injection amount and an ignition timing corresponding to the control of lowering the engine speed or the inconsistency of the overlap period when a failure occurs. In another example (an example shown in FIG. 11 described later), the maximum speed of the engine speed is regulated by changing the gear position of the automatic transmission 41, and the solenoid valve 42 of the automatic transmission 41 is controlled. It is configured to output a change signal to the transmission controller 43 that outputs a control signal to the shift controller 43. In order to make a gearshift determination, the gearshift controller 43 receives a rotation signal from the turbine sensor 44,
Speed change signal from inhibitor switch 45, vehicle speed sensor 46
, A throttle opening signal from the throttle sensor 38, and the like.

The detailed structure of the variable valve timing mechanism 27
As shown in the figure, a cylindrical spacer 53 is fixed to the end of the exhaust side camshaft 12, and a driving pulley 54 is mounted outside the spacer 53. This pulley 54 has a boss 55
The distal end is in sliding contact with the outer periphery of the distal end of the spacer 53, and the base end of the boss portion 55 is fixed to a cylindrical connecting member 56 rotatably mounted on the exhaust camshaft 12. A first gear 57 is spline-coupled to the other end of the connecting member 56, and is fixed by a lock nut 58. The first gear 57 is meshed with a second gear 59 fixed to the tip of the intake camshaft 11.

Inside the boss 55 of the pulley 54, an annular piston 60 is incorporated between the pulley 54 and the spacer 53. piston
Reference numeral 60 denotes a structure divided into two parts in the axial direction, and both divided parts are fixed to each other by a plurality of pins 61 arranged at equal intervals in the circumferential direction. Helical splines 62 and 63 in opposite directions are formed inside and outside the piston 60.
A helical spline 64 is formed outside the spacer 53 with respect to the spline 62 inside the piston 60, and a pulley 54 is formed with respect to the spline 63 outside the piston 60.
A helical spline 65 is formed on the outer periphery of the boss portion 55. The piston 60 is biased toward the distal end by a spring 66 mounted between the piston 60 and the end face of the connecting member 56.

The exhaust side camshaft 12 has an oil passage along the axis.
67 are formed. One end of the oil passage 67 communicates with a passage 67a formed in the camshaft 12 in a radial direction at a portion of a bearing portion 72 that supports the camshaft 12, and coincides with a shaft outer peripheral surface opening of the passage 67a. Bearing 72
An annular groove 72a is formed in the inner periphery, and an oil supply passage 28 that has passed from the oil pump through a three-way solenoid valve 29 passes through the bearing 72 and is communicated with the annular groove 72a.

On the other hand, the cylindrical spacer 53 is fixed to the exhaust side camshaft 12 by a fixing bolt 69 via a stopper member 68. The fixing bolt 69 has the oil passage 67
Is provided with an axial through hole 70 that communicates with the shaft. Also,
At the tip of the boss portion 55 of the pulley 54, a pressure chamber 71 for guiding the oil pressure from the oil passage 67 facing the head of the piston 60 is provided. When oil pressure is introduced into these pressure chambers 71 through the oil passage 67 to compress the spring 66 and move the piston 60 in the axial direction, the splines 62 and 63 formed on the inner and outer circumferences of the piston 60 in opposite directions are formed. Mating spacer 5
One of the pulley 3 and the pulley 54 rotates relative to the other. Thus, the phase, that is, the valve timing, between the exhaust-side camshaft 12 and the pulley 54 integrated with the spacer 53 changes.

The hydraulic pressure introduction control is performed by the three-way solenoid valve 29.
Engine controller 36 that outputs drive signals to
This controller 36
Determines the operating area (see FIG. 5) of the variable valve timing mechanism 27 corresponding to the current operating state based on the engine load (for example, throttle opening) and the engine speed to determine the communication state of the three-way solenoid valve 29. The change of the overlap is performed in conjunction with the operation of the supercharger 21.

As shown in FIG. 5, the setting of the control characteristics of the operating region of the variable valve timing mechanism 27 is such that the relationship between the engine load Qa / N and the engine rotational speed N is higher than the setting line Lo. This is a region where the hydraulic pressure is introduced into the variable valve timing mechanism 27. At the time of introducing the hydraulic pressure, the opening and closing timing of the exhaust valve 6 is delayed as shown by a solid line in the valve timing of FIG. This is to increase the open overlap period OL1. A low-load low-rotation region I inside the setting line Lo is a region where the introduction of the hydraulic pressure to the variable valve timing mechanism 27 is stopped. When the introduction of the hydraulic pressure is stopped, the valve timing shown in FIG. As described above, the opening / closing timing of the exhaust valve 6 is advanced to reduce the overlap period OL2 in which both the intake valve 4 and the intake valve 4 are simultaneously open.

The small overlap region I corresponds to a non-supercharging region in which the supercharger 21 is not driven, while the large overlap region II corresponds to a region in which the supercharger 21 is driven to perform supercharging. . And, the overlap period OL1 is the supercharger 21
This is large in the region where the supercharger is driven and supercharged.This is because when the amount of residual exhaust gas remaining in the cylinder 1a is reduced in the operation region with high rotation and high load, the temperature in the cylinder decreases, which is advantageous in knocking resistance. Therefore, the overlap period between the exhaust valve 6 and the intake valve 4 is set to be long, and during this period, the exhaust gas is pushed out from the cylinder 1a by the pressurized air from the supercharger 21 to obtain a scavenging effect. Also, the reason for shortening the overlap period OL2 in the low-load low-speed region I is that when the engine shifts to a low-speed region such as idling with the valve overlap set long as described above, the engine speed decreases. When the supercharging pressure decreases and the exhaust pressure increases, the exhaust gas returns to the intake passage 8, and in the low rotation speed range, the amount of the exhaust gas increases and the combustibility decreases. This is to improve combustion stability by shortening the period.

The processing of the engine controller 36 will be described with reference to the flowcharts of FIGS. 7 to 10. The routine shown in FIG. 7 is executed when a failure occurs in introducing hydraulic pressure to the variable valve timing mechanism 27, for example, when a three-way solenoid valve is used.
7 shows a main routine of failure processing control in a case where a wiring coupler is disconnected from or disconnected from 29, a malfunction occurs due to stick generation of a spool valve 32 of a three-way solenoid valve 29, or a case where hydraulic pressure does not rise above a set value.

After the control is started, in step S1, various data such as the engine speed N and the intake air amount Qa are read, and in step S2, based on the characteristics of the map (FIG. 5), the operation state is in a high-load high-speed range where the overlap is large. Determine whether it is II.
If the determination is YES and the area is a large overlap area, a failure determination is made in step S3, while if it is a small overlap area, a failure determination is made in step S4. This failure determination is based on the state of the failure determination flags F1 and F2 that are set to 1 when a failure is detected by the subroutine shown in FIG.

Then, when a failure occurs in the large overlap region II, that is, even when the engine is in a high-load and high-speed operation state, no hydraulic pressure is introduced to the variable valve timing mechanism 27, and the failure occurs while the overlap remains small. At times, control for regulating the maximum engine speed is performed in steps S5 to S7. That is, in step S5, the overspeed fuel cut speed used in the fuel injection routine according to the subroutine of FIG. 9 described later is changed from the high speed value N1 to the low speed value N2 (see FIG. 5), and is set high in step S6. The lubrication condition is relaxed by setting the load of the load fuel cut line Ls lower than the full load line Lf as shown in FIG.

Further, in step S7, a region II having a large overlap
Of the air-fuel ratio and return of the ignition timing to cope with the increase in the residual exhaust gas while the overlap is kept small. When performing the processing in step S7, it may be performed in place of the processing in step S6, or one of the air-fuel ratio correction and the ignition timing correction may be performed.

On the other hand, the determination in step S2 is NO, the determination in step S4 is YES, and a failure occurs in a state where the hydraulic pressure is introduced to the valve timing variable mechanism 27 in a small overlap region,
If the operating state has a large overlap although the overlap should be small, the target rotational speed of the idle rotational speed control is corrected to be high in step S8. This is to improve the decrease in combustibility due to the increase in the amount of exhaust gas returning to the intake port 5 and the increase in residual exhaust gas when the overlap increases in a low-load low-speed state. The correction is performed so as to increase the bypass air.

To explain the failure determination subroutine of FIG. 8, after starting the control, the signal of the oil pressure sensor 39 is read in step S10. Then, in step S11, as in step S3, the operating state is in the region I where the overlap is large or the region II where the overlap is small.
Is determined. In the case of the large overlap region II, the process proceeds to step S12, and based on the output of the hydraulic pressure sensor 39, it is determined whether or not the hydraulic pressure introduced to the variable valve timing mechanism 27 is equal to or greater than a set value. If the determination is NO and the hydraulic pressure is lower than the set value, it means that the three-way solenoid valve 29 or the like is not operating properly and a failure has occurred, so that step S14 is performed.
In step S13, the flag F1 is set to 0 in step S13.

If the determination in step S11 is NO, ie, in the small overlap region I, the process proceeds to step S15 to determine whether or not the hydraulic pressure introduced into the variable valve timing mechanism 27 is equal to or greater than a set value. If the determination is YES and the hydraulic pressure is higher than the set value, a failure has occurred when the three-way solenoid valve 29 and the like are not operating normally, so that the failure determination flag F2 is set to 1 in step S16, and the hydraulic pressure is normally increased. If it has decreased, the flag F2 is set to 0 in step S17. Corresponding to the set of the failure determination flags F1 and F2,
The failure determination in steps S3 and S4 is performed.

Instead of detecting the oil pressure by the oil pressure sensor 39, a solenoid voltage value of the three-way solenoid valve 29 is detected, and it is determined whether or not the driving state of the solenoid valve 29 and the actual operating state are coincident. The determination may be made.

Next, FIG. 9 shows a fuel injection control routine including a correction process at the time of occurrence of a failure. After the control is started, it is determined in step S20 whether or not the engine is started. Ts (fixed value) is calculated, and step S2
In step 2, the final injection pulse Ti is set.

On the other hand, when the engine is not started, the basic injection amount Tb is calculated from the engine speed N and the intake air amount Qa in step S23,
After calculating various correction values Ca such as temperature correction and feedback correction in step S24, it is determined in step S25 whether or not the failure determination flag F1 indicates a failure occurrence state. Then, in the state where a failure has occurred, a correction value Co corresponding to the air-fuel ratio correction of step S7 is calculated in step S26, and a high-load fuel cut corresponding to step S6 is performed in steps S27 and S28. That is, step S27
It is determined whether or not the engine load Qa / N is greater than the set value Ls. If it is, the basic injection amount Tb is set to 0 in step S28 to prevent fuel injection.

The basic injection amount Tb calculated as described above, the correction values Ca, C
On the basis of o, a final injection pulse Ti is calculated in step S29, and the final injection pulse Ti is preset in an injection counter in step S32, and fuel injection is performed.
In steps S30 and S31, a fuel cut corresponding to the engine speed N corresponding to step S5 is performed. That is,
In step S30, the engine speed N is set according to the failure occurrence state.
(Fig.) It is determined whether it is higher or not, and if it is higher, step S3
In step 1, the last injection pulse is set to 0, and the fuel injection is stopped.

Next, FIG. 10 is an ignition advance control routine including a correction process at the time of failure occurrence.After starting the control, it is determined in step S41 whether or not the engine is starting. On the other hand, in the case other than the starting time, it is determined whether or not the engine is idling in step S43. When the engine is idling, the idling advance angle θidl is calculated in step S44, and the final advance angle θ is calculated in step S45.
Set to ig.

When the engine is not idling, the process proceeds to step S46, where the basic advance angle θb is calculated from the map based on the engine speed N and the intake air amount Qa, and various correction values θa such as temperature correction are calculated in step S47. It is determined from the state of the failure determination flag F1 whether or not a failure has occurred. Then, in a state where a failure has occurred, a correction value θc corresponding to the ignition advance correction in step S7 is calculated in step S49, and in a normal state, this correction value is set to 0 in step S50.

The basic advance angle θb, correction value θa,
In step S51, the final ignition advance angle θig is calculated based on θc, and in step S52, the final ignition advance angle θig is preset in an ignition counter to execute ignition.

According to the embodiment as described above, a failure occurs in the hydraulic system for the valve timing
When the lubricating oil amount for the 12 bearings 72 is insufficient,
By changing the fuel cut speed Nc and setting the fuel cut load Ls, the maximum speed is regulated low to suppress the occurrence of problems due to poor lubrication, and the occurrence of knocking due to incompatibility between the operating state and the overlap period And the like can be solved by correcting the air-fuel ratio and / or the ignition timing.

Next, FIG. 11 is a flowchart of a process of the shift controller 43 in an example in which the shift point of the automatic transmission 41 is changed to regulate the maximum engine speed when a failure occurs as another embodiment. Show.

After the start of the control, various data such as the throttle opening and the vehicle speed are read in step S61, and the occurrence of a failure is determined in step S62 based on the state of the failure determination flag F1. In the state where no failure has occurred, in step S63, in the shift pattern shown in FIG. 12, the shift characteristic by the shift line U1 set on the normal high speed side indicated by the solid line is selected. Then, it is determined in step S64 whether or not it is a shift point. When the shift point is reached, a corresponding shift command is issued in step S68, and a signal is output to the solenoid valve 42 of the transmission 41 in step S70.

On the other hand, in the state where a failure has occurred, the speed change line U2 set at the low speed side as indicated by the broken line in FIG. 12 in step S65.
Select the shift characteristics according to. Then, in step S66, it is determined whether or not the current point is a shift point.
In S67, it is determined whether or not the gear position after the shift is other than the first speed. When the shift is other than the first speed, the corresponding shift command is issued in the step S68. After a shift stop command is issued in S69, step S70
And outputs a signal to the solenoid valve 42 of the transmission 41.

In this example as described above, a failure occurs in the hydraulic system for the variable valve timing
When the lubricating oil amount for the 12 bearings 72 is insufficient,
By changing the shift pattern so as to shift from a low vehicle speed state to a higher gear stage with a smaller gear ratio, the engine speed is controlled to be lower even at the same vehicle speed, and the gear ratio is reduced even at a lower vehicle speed. The shift to the first speed, which is large, is stopped to suppress the maximum engine speed.

In the above embodiment, the on / off of the introduction of the hydraulic pressure to the variable valve timing mechanism 27 is switched by the three-way solenoid valve 29, but the operating state is operated by draining the supply hydraulic pressure. Even if it is configured to introduce the engine lubricating oil through the bearing 72 of the camshaft 12, the same is applicable.

Further, the variable valve timing mechanism 27 having the structure shown in FIG. 4 can be formed compact, and may vary the phase of the exhaust valve 6 or the phase of the intake valve 4. Further, the design of the variable valve timing mechanism 27 can be appropriately changed to another configuration.

(Effect of the Invention) According to the present invention as described above, the engine lubricating oil is introduced into the variable valve timing mechanism mounted on the camshaft of the engine via the camshaft bearing, and the hydraulic pressure is changed during the specific operation. When changing the valve timing by acting on the mechanism, when the occurrence of a failure state in which the hydraulic pressure by the hydraulic control means cannot act on the variable valve timing mechanism is detected by the failure detection means, the failure control means is activated, By limiting the maximum engine speed by stopping the supply and controlling the speed of the automatic transmission, seizure etc. may occur on the camshaft bearing even if the engine lubrication oil supply is insufficient. This can be prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of the present invention, FIG. 2 is an overall configuration diagram of an engine having a valve timing control device in a specific example, and FIG. 3 is a cross-sectional view of a main part showing a configuration example of a three-way solenoid valve. FIG. 4, FIG. 4 is a sectional view of a main part showing a specific example of a variable valve timing mechanism, FIG. 5 is a characteristic diagram showing a control region of the variable valve timing mechanism, and FIG. 6 is a change of overlap between an exhaust valve and an intake valve. 7 to 10 are flow charts for explaining the processing of the engine controller, FIG. 11 is a flow chart for explaining the processing of the transmission controller in another embodiment, and FIG. The figure is a shift map showing the shift characteristics in the process of FIG. E, 1… Engine, C, 11,12 …… Camshaft, A, 27 ……
Variable valve timing mechanism, B, 72: Cam shaft bearing, D: Hydraulic control means, F: Failure detection means, G:
Fault control means, 4 ... intake valve, 6 ... exhaust valve, 28 ...
Oil supply passage, 29 …… Three-way solenoid valve, 36,43
…… Controller, 39 …… Hydraulic sensor.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hidefumi Fujimoto 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (56) References JP-A-61-145310 (JP, A) JP-A-63 -1727 (JP, A) JP-A-61-268810 (JP, A) JP-A-1-110844 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01L 13/00301 F01L 13/00 302 F01L 1/34

Claims (5)

(57) [Claims] An engine lubricating oil is introduced into a variable valve timing mechanism mounted on a camshaft of an engine via a camshaft bearing, and the valve timing is changed by applying a hydraulic pressure to the variable valve timing mechanism during a specific operation. A valve timing control device provided with hydraulic pressure control means for lubricating the camshaft bearing, wherein failure detection means for detecting a failure state in which the hydraulic pressure by the hydraulic control means cannot act on the variable valve timing mechanism; A valve timing control device for an engine, comprising: a failure control means for receiving a signal from the failure detection means and suppressing a maximum engine speed when an occurrence of a failure is detected. 2. The valve timing control device for an engine according to claim 1, wherein the specific operation of supplying the oil pressure to the variable valve timing mechanism is a high rotation time. 3. The automatic transmission according to claim 1, wherein the control unit changes the shift point of the gear position of the automatic transmission to a low rotation side to suppress the maximum rotation speed of the engine. Engine valve timing control device. 4. The valve timing control device according to claim 1, wherein the camshaft bearing is lubricated by a part of engine lubrication oil supplied to the variable valve timing mechanism. 5. The valve timing control device for an engine according to claim 1, wherein said failure control means stops the fuel supply to the engine to suppress the maximum engine speed to a low value.