JP2810401B2 - Engine valve timing control device - Google Patents

Description

The present invention relates to a valve timing control device for an engine, which restricts a change in valve timing or reduces a combustion control amount when a fluid pressure supplied to a fluid pressure actuator decreases. It relates to what is corrected.

(Prior art)

Conventionally, as an engine with a supercharger, for example, JP-A-61-18
As disclosed in JP-A-753 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 range. 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 to promote scavenging of the burned gas in the combustion chamber, and the occurrence of knocking is controlled.

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 in which an electromagnetic on-off valve is provided in a relief passage for relieving the pressure oil supplied to the actuator, and the electromagnetic on-off valve is opened and closed so that the valve timing is switched to a large or small value via a hydraulic actuator. An apparatus is described. Pressurized oil is supplied from the oil pump of the engine to the hydraulic actuator through the oil gallery of the cylinder block and the cylinder head. In the rotation range where the engine speed is equal to or lower than a predetermined high speed, the valve is set using the engine speed and the engine load as parameters. Timing changes.

[Problems to be solved by the invention]

In the valve timing control device using the hydraulic actuator, the oil pressure of the pressurized oil also decreases as the engine speed decreases, so that the oil pressure drops significantly when the engine speed is low such as at idle. As a result, the operating time of the hydraulic actuator becomes longer or inoperable, for example, when the valve timing is switched due to acceleration in a low rotation state.

However, in response to switching of the normal intake / exhaust overlap amount from "small" to "large", the map for setting the base advance angle of the ignition timing is switched to increase the advance amount, or to increase the air-fuel ratio to the rich air-fuel mixture side. Since the combustion control amount is changed by changing the valve timing, if the operation time of the hydraulic actuator becomes longer or becomes inoperable as described above, the valve timing has not actually been switched yet. Nevertheless, since the combustion control amount is changed, problems such as occurrence of knocking occur.

An object of the present invention is to provide a valve timing control device that does not change the valve timing when the hydraulic pressure is low in a low rotation speed range, and to correct the combustion control amount in synchronization with the valve timing change when the hydraulic pressure is low in a low rotation speed range. To provide a valve timing control device.

[Means for solving the problem]

The engine valve timing control device according to claim 1,
A valve timing changing device that changes intake timing or exhaust timing via a fluid pressure actuator that receives supply of pressure fluid whose pressure increases in accordance with an increase in engine speed, and changes valve timing using at least the engine load as a parameter In the engine valve timing control device, when the engine speed is in a low speed range set in the engine speed range where the pressure of the pressure fluid is equal to or less than a predetermined value, the valve timing using the engine load as a parameter is used. Is provided with a change restricting means for restricting a change from being made.

The engine valve timing control device according to claim 2 is
In the first aspect of the present invention, the fluid pressure actuator is provided at an end of a cam shaft.

The engine valve timing control device according to claim 3 is
In the invention of claim 1, a control valve for opening and supplying a pressure fluid is provided in a pressure fluid supply path to the valve timing changing device, and the change restricting means restricts a valve opening operation of the control valve. It is constituted in.

The engine valve timing control device according to claim 4 is:
In the first aspect of the present invention, the low rotation range is set based on a pressure when the pressure fluid is in a high temperature state.

The engine valve timing control device according to claim 5,
In an engine valve timing control device provided with a valve timing changing device for changing intake timing or exhaust timing via a fluid pressure actuator which receives supply of a pressure fluid whose pressure increases in accordance with an increase in engine speed, the valve timing During the change operation, control amount correction means for correcting the engine combustion control amount in synchronization with the change of the valve timing is provided, and the time for correcting by the control amount correction means is such that the pressure of the pressure fluid becomes equal to or less than a predetermined value. It is configured to be longer at low rotation than at high rotation.

The engine valve timing control device according to claim 6,
In the invention of claim 5, the control amount correction means is configured to correct the combustion control amount of the engine through changing the ignition timing of the engine.

The engine valve timing control device according to claim 7,
In the invention of claim 5, the control amount correction means is configured to correct the engine combustion control amount through a change in the air-fuel ratio of the engine.

The valve timing control device for an engine according to claim 8,
A valve timing change device that changes intake timing or exhaust timing via a hydraulic actuator that receives supply of pressure fluid whose pressure increases in response to an increase in engine speed is provided, and changes valve timing using at least engine load as a parameter. In the valve timing control device for an engine, the overlap amount of the intake and exhaust valves is reduced in a predetermined low-speed low-load region, and the overlap amount is reduced in the other low-speed low-load region. Control map set to be larger than the above, operating means for operating the valve timing changing device based on the control map, in the low rotation region set lower than the predetermined low rotation, the operating means Valve timing prohibits changes to valve timing It is obtained by a grayed change prohibition means.

[Action]

According to the first aspect of the invention, when the engine speed is in the low rotation range, the fluid pressure supplied to the fluid pressure actuator becomes low, so that the operation of the valve timing changing device becomes unstable. Sometimes, the change restricting means restricts the valve timing from being changed using the engine load as a parameter, so that the valve timing is not changed. Therefore, there is no occurrence of operation delay or operation failure of the valve timing changing device caused by low fluid pressure supplied to the fluid pressure actuator.

Since the low rotation range is set in an engine speed range where the pressure of the pressure fluid is equal to or lower than a predetermined value, the pressure of the pressure fluid is equal to or lower than the predetermined value, and the valve timing changing device does not normally operate. Of the valve timing can be prevented.

According to the second aspect of the invention, the same operation as the first aspect is achieved, but since the fluid pressure actuator is provided at the end of the camshaft, the structure of the valve timing changing device can be simplified and downsized. .

According to the third aspect of the invention, the same operation as the first aspect is achieved, but when the control valve provided in the pressure fluid supply path to the valve timing changing device is opened, pressure is supplied to the valve timing changing device. . The change restricting means restricts a valve opening operation of the control valve, thereby restricting a change in valve timing.

According to the fourth aspect of the invention, the same operation as the first aspect is achieved, but the low rotation range is set based on the pressure when the pressure fluid is in a high temperature state. That is, even at the same engine speed, in consideration of the fact that the pressure is lower when the pressure fluid is in a high temperature state than when it is in a low temperature state, the low rotation speed is determined based on the pressure when the pressure fluid is in a high temperature state. The area is set.

According to the fifth aspect of the present invention, during the operation of changing the valve timing, the control amount correcting means corrects the engine combustion control amount in synchronization with the change of the valve timing. It can be adapted to valve timing.

And when the engine speed is in the low speed range,
Since the fluid pressure supplied to the fluid pressure actuator becomes low, the operation of the valve timing changing device is unstable and an operation delay occurs.
At the time of low rotation at which the pressure of the pressure fluid is equal to or less than the predetermined value, the pressure is made longer than at the time of high rotation.

According to the sixth aspect of the present invention, the same operation as in the fifth aspect is provided, but the control amount correction means corrects the combustion control amount of the engine through changing the ignition timing of the engine. The timing can be controlled according to the valve overlap amount.

According to the seventh aspect of the invention, the same effect as that of the fifth aspect is obtained, but the control amount correction means corrects the engine combustion control amount through the change of the engine air-fuel ratio. It can be controlled to a value corresponding to the amount of valve overlap.

In the invention of claim 8, the overlap amount of the intake / exhaust valve is reduced in a predetermined low rotation low load region, and the overlap amount is larger than the overlap amount in the low rotation low load region in other regions. The control map set to perform the operation and the actuating means for operating the valp timing changing device based on the control map are provided, so that the overlap amount of the intake and exhaust valves is reduced in an area other than the predetermined low-speed low-load area. By increasing the value, scavenging of burned gas can be promoted and knocking can be prevented. Further, in a low rotation range set lower than the predetermined low rotation, valve timing change prohibition means for prohibiting the operation means from changing the valve timing is provided. There is no operation delay or malfunction of the valve timing changing device caused by low fluid pressure supplied to the actuator.

〔The invention's effect〕

According to the first aspect of the present invention, as described in the above section, the change restricting means is provided to restrict the valve timing from being changed using the engine load as a parameter when the engine is in the low rotational speed range. Therefore, the valve timing is not changed in the low rotation speed range, and the operation delay or malfunction of the valve timing changing device in the low rotation speed range is reliably prevented, and the above-mentioned operation delay or malfunction is caused. It is possible to prevent erroneous control of the engine. And
It is possible to prevent the valve timing from being changed when the pressure of the pressure fluid is equal to or less than the predetermined value and the valve timing changing device does not operate normally.

According to the second aspect of the invention, the same effect as that of the first aspect is obtained, but since the fluid pressure actuator is provided at the end of the camshaft, the structure of the valve timing changing device is simplified.
The size can be reduced.

According to the third aspect of the present invention, the same effect as the first aspect is obtained, but the operation of the valve timing changing device can be controlled through the control valve having a simple structure.

According to the fourth aspect of the invention, the same effect as in the first aspect is obtained, but the low rotation range is set based on the pressure when the pressure fluid is in the high temperature state. Sometimes, early effects can be achieved.

According to the fifth aspect of the present invention, during the operation of changing the valve timing, the control amount correcting means corrects the combustion control amount of the engine in synchronization with the change of the valve timing. Therefore, the combustion control amount during the operation of changing the valve timing can be adapted to the valve timing.

And when the engine speed is in the low speed range,
Since the fluid pressure supplied to the fluid pressure actuator becomes low, the operation of the valve timing changing device is unstable and an operation delay occurs.
At the time of low rotation when the pressure of the pressure fluid is equal to or lower than the predetermined value, the pressure is made longer than at the time of high rotation.

According to the sixth aspect of the invention, the same effect as that of the fifth aspect is obtained, but the ignition timing can be controlled to a timing according to the amount of overlap of the intake and exhaust valves.

According to the seventh aspect of the invention, the same effect as that of the fifth aspect is obtained, but the air-fuel ratio can be controlled to a value corresponding to the amount of overlap of the intake and exhaust valves.

According to the invention of claim 8, in an area other than the predetermined low-speed low-load area, the amount of overlap between the intake and exhaust is increased, the exhaust of burned gas is promoted, and knocking can be prevented. Further, similarly to the first aspect, there is no occurrence of operation delay or malfunction of the valve timing changing device caused by low fluid pressure supplied to the fluid pressure actuator.

〔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 a supercharged engine of a two-inlet and two-exhaust type of each cylinder of 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 boat 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. An injector 15 for injecting fuel toward each intake port 2 is mounted on the branch pipe 17. Throttle valve 13
The throttle valve 13 is provided with a throttle opening sensor 18 for electrically detecting the opening of the throttle valve 13 and an idle switch (not shown) opened when the throttle valve 13 is fully closed. A bypass passage 19 for bypassing the supercharger 14 is provided, a bypass valve 20 is provided in the bypass passage 19, and the bypass valve 20 is an actuator 21 in which a boost negative pressure is introduced through a negative pressure introducing passage 22. Driven. The characteristics of the valve opening 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 the pulley 26 of the input shaft 14a is connected to the clamp shaft pulley 6 by a belt or a chain. The electromagnetic clutch 25 and a control unit 27 for controlling an overlap switching solenoid 31 of a valve timing changing mechanism 30 for switching the intake / exhaust overlap amount to be described later are provided.
The signal from the throttle valve 12, the signal from the throttle opening sensor 18, the signal from the idle switch, the engine speed signal N from the distributor, and the like are input.

Next, the valve timing changing mechanism 30 will be described with reference to FIGS. In this engine valve gear, a cylindrical spacer is provided at the end of the exhaust camshaft 5.
The drive 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. This first gear 8
A second gear 9 fixed to the tip of the intake camshaft 4 is meshed and connected. 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, and both divided parts are fixed to each other by a plurality of pins 39 arranged at equal intervals in the circumferential direction. 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 splice 40 inside the piston 38, and the pulley 7 is formed on the helical spline 41 on the outer periphery of the piston 38.
A helical spline 43 is formed on the inner periphery of the boss portion. The piston 38 is biased 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 connected to a cylinder head 36.
The bearing 36B is rotatably supported by the bearing 36B, and the end of the pivot 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, the switching valve 52 is in the discharge position and the oil passage 45 is connected to the drain passage 53 as shown in FIG. 3, and when the solenoid 31 is ON, the switching valve 52 is in the supply position. The oil passage 45
(Oil gallery). Pressurized oil is supplied to the hydraulic pressure supply passage 54 from a lubricating oil pump driven by a crankshaft, and this hydraulic pressure increases with a characteristic as shown in FIG. 7 as the engine speed increases.

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.

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. Program P that controls the electromagnetic clutch 25 according to the state
A, a program PB for intake / exhaust overlap amount control for switching the intake / exhaust overlap amount between large and small via the switching solenoid 31 in accordance with the operation state, and other programs for ignition timing control and fuel injection control, etc., are previously input and stored. ing.

FIG. 8 is an explanatory diagram of various areas included in the programs PA and PB in tables and maps. The area A inside the curve a holds the switching solenoid 31 in the OFF state and the oil passage 4
In the overlap small area in which the hydraulic pressure is removed and the intake / exhaust overlap amount is maintained at “small”, the areas B and C outside the curve a maintain the switching solenoid 31 ON to supply the oil pressure to the oil passage 45 and supply the oil. A large overlap region where the amount of exhaust overlap is maintained at “large”, regions A and B inside the folding line b are electromagnetic clutch OFF regions where the supercharger 14 is not operated, and a region C outside the folding line b is a supercharger 14. Is an electromagnetic clutch ON region (supercharging region) in which the supercharging is performed by operating the. The low speed range predetermined rotational speed N ₁ or less of the overlap large area is an area that substantially overlaps the small region by the control program as described below. 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. 5). Next, an outline of the routine of the control program PB will be described with reference to FIG. In the figure, Si (i = 1, 2, 3,...) Indicates each step, and this routine is an interrupt process at predetermined time intervals or a crank output from a crank angle sensor (not shown) every one rotation of the crankshaft. It is executed by interrupt processing every time an angle signal is input.

FIG. 9 shows a routine for controlling the intake / exhaust overlap amount via the valve timing changing mechanism 30 including the switching solenoid 31. After the start of the control, the engine speed N and the intake air amount Q are read, and the operation state overlaps. large regions (regions B and C of Figure 8) is determined whether (S2), when the Yes is determined whether the engine speed N is larger than the predetermined speed N ₁ (S3), N of> N ₁ At this time, the switching solenoid 31 is controlled to be ON (S4), 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. S2 is at low revs result be the result overlap the large region of the determination of the overlap small areas when and S3 not overlap large region of the determination of the N ≦ N ₁ of the switching solenoid 31 OF
F (S5), the oil pressure in the oil passage 45 is discharged,
The timing changing mechanism 30 switches the intake / exhaust overlap amount to “small”. After the execution of the above routine, the process returns to the main routine.

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

The oil pressure supplied to the oil pressure supply passage 54 decreases as the engine speed decreases as shown in FIG. 7, and the oil pressure becomes lower when the oil temperature is higher than when the oil temperature is lower due to the viscosity of the oil. As a result, the operation time from when the switching solenoid 31 is switched from OFF to ON to when the intake / exhaust overlap amount is switched to “large” increases as the engine speed decreases as shown in FIG. .

I.e. when against such spring 44 of the valve timing changing mechanism 30 the piston 28 is oil pressure is lower than the minimum oil pressure P ₁ necessary for switching reliably actuated intake and exhaust amount of overlap from "small" to "large" when the engine speed is Figure 7 below a predetermined rotational speed N ₁ of the low-speed range, while the operation of the valve timing changing mechanism 30 is uncertain, the ignition timing control in accordance with the intake and exhaust amount of overlap switching is since is also switched map of basic ignition timing (base advance angle) setting, when operating the valve timing change mechanism 30 when: the predetermined rotational speed N _1, intake and exhaust overlap amount actually still is "large" The ignition timing control of the erroneous control is performed assuming that the switching has been switched to "large" although the switching has not been performed.

Therefore, in the valve timing control device of the present embodiment,
When the engine speed is less than the predetermined rotational speed N ₁ is adapted not to perform any change of valve timing.

<Second Embodiment> ... See FIGS. 10 to 14 In this embodiment, the hydraulic pressure supplied to the valve timing changing mechanism 30 fluctuates according to the engine speed N, and as a result, the valve timing switching is performed. In view of the fact that the operating time varies as shown in FIG. 6, the ignition timing is corrected during the operating time in synchronization with the switching of the valve timing. However, the configuration other than the control program is the same as that of the above embodiment.

The ignition timing of the engine E is controlled by an ignition timing control program, and the base advance amount of the ignition timing is set in advance for each of a number of small regions obtained by dividing the engine operation region as shown in FIG. RO as the base advance amount map
The ignition timing in the large overlap region (region outside the curve a) is stored in the small overlap region (curve a
It is then advanced by Ig _o compared with the ignition timing of the inner region). By the way, during the operation time immediately after the valve timing is changed by the valve timing control, the ignition timing control is performed as if the valve timing has been changed even though the valve timing has not been changed yet. is there. The valve timing change control program stored in the ROM of the microcomputer of the control unit 27 includes a valve timing change mechanism that sets the engine speed N as a parameter as shown in FIG.
30 operating hours (this is when switching solenoid 31 is turned on from OFF)
) Is stored in advance as a table.

FIG. 10 shows a routine of the valve timing change control and the ignition timing correction control of the present embodiment, and this routine is executed by an interrupt process based on a crank angle signal inputted every one revolution of the crankshaft. Note that this routine is also
Stored in M.

After the start of the control, the engine speed N and the intake air amount Q are read (S10), and it is then determined whether or not the operation state of the engine E is in the large overlap region (regions B and C in FIG. 8) (S1).
1) If Yes, it is determined whether or not the operation state was the small overlap area at the time of the previous interruption (S12). However,
This determination is made using a flag (not shown). When the result of the above determination is Yes, that is, when the transition is made from the small overlap region to the large overlap region, the switching solenoid 31 is controlled to be ON (S13), the hydraulic pressure is supplied to the pressure chamber 49, and the intake / exhaust overlap amount is set to “ Large ". Next, operation time T _l read out from a table using the engine rotational speed N is set in the soft timer T (S1
4), then FIG. 13 of the first correction amount ΔIg ignition timing equal the retard direction _o the correction amount ΔIg is output to the ignition timing control device (S15), the ignition timing is corrected at the ignition timing control.

Next, when the result of determination in S12 is No, that is, when the overlap area was also the previous time, the switching solenoid 31 is controlled to be ON, and the intake / exhaust overlap amount is held at "large" (S16). It is determined whether or not the timer T is zero (S17).
The ignition timing correction amount ΔIg as shown in FIG. 13 by using the elapsed time T _i of the timer T when not elapsed, that operation time T _l is calculated when (S18), the next to the retard direction The correction amount ΔIg is output (S19). As a result of the determination in S17, when the timer T is zero, the operation time _Tl has already elapsed and no correction is required, so that the process returns to the main routine.

If the result of determination in S11 is that the vehicle is in the small overlap region, the process proceeds to S20, where it is determined whether or not the previous time was the large overlap region. 31 is controlled to OFF and intake / exhaust overlap amount is "small"
Switched to (S21), then operation time T _l as with the soft timer T is set (S22), then the ignition timing to the equal advance direction on the first ignition timing correction amount ΔIg of FIG. 13 The correction amount ΔIg is output (S23).

As a result of the determination in S20, if the previous time is also in the small overlap region, the switching solenoid 31 is controlled to be turned off, the intake / exhaust overlap amount is held at "small" (S24), and then the timer T is set to zero. the determined (S25), the elapsed time T _i of the timer T when the clogging operation time T _l when no is not passed
Is used to calculate the ignition timing correction amount ΔIg (S26), and then the correction amount ΔIg in the advance direction is output (S27). S25
If the result of the determination is that the timer T is zero, the operation time _Tl has already elapsed and no correction is required, so the program returns to the main routine.

In the valve timing control apparatus of the present embodiment, switching of the valve timing, since the ignition timing is corrected to the operating time T _l of the valve timing changing mechanism 30 in synchronism with the switching has elapsed, the valve timing change mechanism 30 Erroneous control of the ignition timing due to the operation delay can be prevented.
In particular, when the engine speed N is in the low rotation range, the operation delay becomes remarkable due to the decrease in the oil pressure. Therefore, performing the ignition timing correction is extremely effective in terms of the combustion control of the engine E.

In the above embodiment, the ignition timing is corrected in synchronization with the switching of the valve timing. However, instead of correcting the ignition timing, the valve timing is synchronized with the switching of the valve timing as shown in FIG. The air-fuel ratio may be corrected until the operating time _Tl of the changing mechanism 30 elapses. That is, when the switching solenoid 31 is switched from OFF to ON, the air-fuel ratio is largely corrected in the mixture rich direction to prevent knocking, and when the switching solenoid 31 is switched from ON to OFF, the air-fuel ratio is mixed to compensate for a decrease in output. The correction is made smaller in the air rich direction.

As described above, when the air-fuel ratio is corrected, the ignition timing correction amount ΔIg in the routine of FIG. 10 may be replaced with the air-fuel ratio correction amount, and the description of this control routine will be omitted.

<Third Embodiment> See FIG. 15 The valve timing control device of the engine of the third 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. 15, the switching solenoid 31 and the switching valve
A relief valve comprising a relief valve body 61 from which an end of the oil passage 45 is provided on the end side of the exhaust camshaft 5 and a relief solenoid 62 for controlling the opening and closing of the relief valve 61, from which the plug 52 and the plug 51 are removed. There are 60 provided. Relief valve 60
When the valve is opened, part of the oil pressure in the oil passage 45
Of the pressure chamber 49 is reduced.

The hydraulic supply path 54 is formed in the pivotal support portion 36A of the cylinder head 36 and connected to the oil gallery of the cylinder head 36,
Pressurized oil is supplied from an oil gallery. The oil pressure supply passage 54 is provided with an annular groove 54a of the exhaust camshaft 5 and a through hole 54b.
And are communicated with the oil passage 45.

When the operating state of the engine E is in the small overlap region, the relief solenoid 62 is held OFF and the valve is opened, and when the engine E is in the large overlap region, the relief solenoid 62 is switched ON and closed. However, the relief solenoid 62 when the same manner as in the case the engine rotational speed N ≦ predetermined rotational speed N ₁ of the first embodiment regardless of the magnitude of the load CF
It is held in F.

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.

[Brief description of the drawings]

The drawings show an embodiment of the present invention, in which a primary part is a main part configuration diagram of a supercharged engine, FIG. 2 is a sectional view of a valve timing changing mechanism, FIG. 3 is a sectional view of a switching valve, and FIG. 4 is an explanatory diagram of valve timing, FIG. 5 is a characteristic diagram of an opening degree of a bypass valve, FIG. 6 is a characteristic diagram of an operation time of a valve timing changing mechanism, FIG. 7 is a characteristic diagram of pressurized oil hydraulic pressure, FIG. Is an explanatory diagram of a large overlap area and a small overlap amount area, etc., FIG. 9 is a flowchart of a routine of intake / exhaust overlap amount control, and FIG. 10 is a flowchart of a routine of intake / exhaust overlap amount control and ignition timing correction control. FIG. 11 is a conceptual diagram of a map of a base advance amount of an ignition timing, FIG. 12 is an explanatory diagram of an operation time, FIG. 13 is an explanatory diagram of an ignition timing correction amount, and FIG.
FIG. 14 is an explanatory diagram of the air-fuel ratio correction amount, and FIG. 15 is a diagram corresponding to FIG. 2 of a valve timing changing mechanism according to another embodiment. E: engine, 4: intake camshaft, 5: exhaust camshaft, 12: air flow meter, 27: control unit, 30: valve timing change mechanism, 31: switching solenoid, 60: Relief valve, 62 ……
Solenoid for relief.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-150449 (JP, A) JP-A-63-124839 (JP, A) Fully open 63-112 (JP, U) Really open Showa 61- 186708 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F01L 13/00 301 F01L 13/00 302 F01L 1/34 F02D 13/02

Claims (8)

(57) [Claims] A valve timing changing device for changing an intake timing or an exhaust timing via a fluid pressure actuator which receives a supply of a pressure fluid whose pressure increases in accordance with an increase in the engine speed; In the valve timing control device of the engine, the valve load is changed, and when the engine speed is in a low speed range set in the engine speed range in which the pressure of the pressure fluid is equal to or lower than a predetermined value, the engine load is reduced. An engine valve timing control device, comprising a change restricting means for restricting a change of a valve timing as a parameter. 2. The engine valve timing control device according to claim 1, wherein said fluid pressure actuator is provided at an end of a camshaft. 3. A control valve for supplying a pressure fluid by opening a valve in a pressure fluid supply path to the valve timing changing device, wherein the change restricting means restricts a valve opening operation of the control valve. The valve timing control device for an engine according to claim 1, wherein: 4. The engine valve timing control device according to claim 1, wherein the low rotation range is set based on a pressure when the pressure fluid is in a high temperature state. 5. A valve timing control of an engine provided with a valve timing changing device for changing an intake timing or an exhaust timing via a fluid pressure actuator which receives a supply of a pressure fluid whose pressure increases in accordance with an increase in the engine speed. In the apparatus, during the operation of changing the valve timing, control amount correction means for correcting the combustion control amount of the engine in synchronization with the change of the valve timing is provided, and the time to be corrected by the control amount correction means is set to the pressure of the pressure fluid. The valve timing control device for an engine is configured to be longer at a low rotation speed than at a predetermined rotation speed than at a high rotation speed. 6. The valve timing control of an engine according to claim 5, wherein said control amount correction means is configured to correct the combustion control amount of the engine through changing the ignition timing of the engine. apparatus. 7. The valve timing control of an engine according to claim 5, wherein said control amount correction means is configured to correct the combustion control amount of the engine through a change in the air-fuel ratio of the engine. apparatus. 8. A valve timing changing device for changing an intake timing or an exhaust timing via a fluid pressure actuator receiving a supply of a pressure fluid whose pressure increases in accordance with an increase in the engine speed, wherein at least the engine load is controlled by a parameter. In the valve timing control device for an engine in which the valve timing is changed, the overlap amount of the intake / exhaust valve is reduced in a predetermined low-speed low-load flow region, and the overlap amount is reduced in the other regions by the low-speed low-load. A control map set to be larger than the overlap amount of the region, an actuation means for operating the valve timing changing device based on the control map, and a low rotation region set lower than the predetermined low rotation, Change of valve timing is prohibited for the above operation means The valve timing control apparatus for an engine characterized by comprising a valve timing change prohibition means, the for.