JP2982604B2 - Valve timing control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for controlling the opening and closing timing of intake and exhaust valves in accordance with the operation state of an internal combustion engine.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a valve timing control apparatus which changes a rotation phase of a camshaft according to an operation state of an engine to advance or delay a valve opening / closing timing. The output of the engine and the fuel efficiency are improved by adjusting the timing of opening and closing the valves in the engine.

[0003] In such a valve timing control device, the engine may be stopped in a state of being advanced. For example, this state occurs when the engine is emptied immediately before stopping the engine. When the engine is subsequently started in this state, not only does the engine not start smoothly, but also there is a problem in that the fuel efficiency deteriorates.

In order to solve the problem as described above, Japanese Patent Laid-Open Publication No. Sho 59-51115 discloses that when an ignition switch (hereinafter, simply referred to as a switch) is turned off, the shutoff of the switch is detected. The power supply cutoff is delayed, and within this delay time, the cam follower is shifted from the high speed side (advance side) cam to the low speed side (retard side) cam, and then the battery power is cut off.
In the case of controlling the displacement of the cam follower only at two positions on the low speed side and the high speed side as disclosed in JP-A-59-51115, the delay time is uniquely determined by the delay circuit.

[0005]

However, in a valve timing control device in which an arbitrary valve timing can be set, the valve timing on the low speed side (predetermined retarded state) depends on the advance amount (valve timing) at the time when the switch is turned off. Since the time required for shifting is different, if the delay time is uniquely determined by the delay circuit, if the delay time is lengthened, the extra time after the valve timing has already shifted to the low speed side is wasted, There is a problem of wasting fuel. If the delay time uniquely determined is too short, the power is shut off before the valve timing is shifted to the low speed side, and there is a problem that idling is deteriorated at the next start.

An object of the present invention is to provide a valve timing control apparatus for an internal combustion engine, which can set a valve timing as desired in a valve timing control apparatus that can perform a smooth transition without waste to an optimal valve timing for starting. Is to provide.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, as shown in FIG. 1, an intake passage M3 and an exhaust passage M4 communicating with a combustion chamber M2 of an internal combustion engine M1 are respectively provided. A variable valve timing mechanism M for driving at least one of an intake valve M5 and an exhaust valve M6 that opens and closes to arbitrarily vary valve timing.
And a drive control means M8 for electrically controlling the driving force for the variable valve timing mechanism M7, the valve timing at the time of the ignition switch-off operation is inappropriate at the time of starting. If the valve timing is appropriate, a delay time calculating means M9 for calculating a delay time based on a return time required to shift from a valve timing at the time of an ignition switch OFF operation to a predetermined valve timing suitable for starting, and a delay time A delay shutoff means M11 for shutting off a battery power supply M10 upon elapse of time, wherein the drive control means M8 drives the variable valve timing mechanism M7 toward a valve timing suitable for starting using the delay time. Is the gist.

[0008] The invention of claim 2 is as shown in FIG.
The variable valve timing mechanism M7 is a mechanism that changes the valve timing of the internal combustion engine M1 according to the driving force supplied from the driving control means M8 and the driving reaction force from the intake valve M5 or the exhaust valve M6. The delay time calculation means M9 includes an operation state detection means M12 for detecting an operation state of the internal combustion engine M1, and a predetermined advance position based on the valve advance amount at the time of the ignition switch-off operation detected by the operation state detection means M12. Return time calculating means M13 for calculating the return time required to shift to
An engine stop time calculating means M14 for calculating an engine stop time which is a time required from the battery power cutoff to the engine stop based on the engine speed at the time of the ignition switch off operation detected by the operating state detecting means M12; And a subtraction means M15 for calculating the delay time by subtracting the engine stop time from the time.

According to a third aspect of the present invention, as shown in FIG. 2, the variable valve timing mechanism M7 controls the valve timing of the internal combustion engine M1 with the driving force supplied from the drive control means M8 and the intake valve M5 or the exhaust valve. A delay time calculating means M9 for detecting an operating state of the internal combustion engine M1; and an operating state detecting means M9 for detecting an operating state of the internal combustion engine M1.
A return time calculating means M13 for calculating a return time required to shift to a predetermined advance position based on the valve advance amount at the time of the ignition switch-off operation detected by 12;
Engine stop time calculating means M14 for calculating an engine stop time which is a time required from the interruption of the battery power supply to the engine stop based on the engine speed at the time of the ignition switch off operation detected by the operating state detecting means M12; The gist of the invention is to include an adding means M16 for calculating the delay time by adding the engine stop time.

[0010]

According to the first aspect of the present invention, as shown in FIG.
If the valve timing at the time of the ignition switch off operation is inappropriate at the start, the delay time calculating means M9 is required to shift from the valve timing at the time of the ignition switch off operation to the valve timing suitable for the start. The delay time is calculated based on the return time. Then, the delay cutoff means M11 delays the cutoff of the battery power supply M10 based on the calculation result of the delay time calculation means M9. On the other hand, the drive control means M8 utilizes the delay time to
7 is driven to a valve timing suitable for starting.

The invention according to claim 2 is an embodiment suitable for a case where the predetermined advance position suitable for starting is set to be more retarded than the advance position at the time of the ignition switch-off operation. That is, the return time calculating means M13 of the delay time calculating means M9 determines the return time required to shift to the predetermined retard position based on the valve advance amount at the time of the ignition switch OFF operation detected by the operating state detecting means M12. Calculate.

Further, the engine stop time calculating means M14 of the delay time calculating means M9 is a time required from the interruption of the battery power supply to the stop of the engine based on the engine speed at the time of the ignition switch off operation detected by the operating state detecting means M12. Calculate the engine stop time. The subtraction means M15 calculates the delay time by subtracting the engine stop time from the return time. The drive control means M8 drives the variable valve timing mechanism M7 toward a predetermined advance position suitable for starting using the delay time. When the delay time has elapsed, the delay cutoff means M11 cuts off the battery power M10. Therefore, the variable valve timing mechanism M by the drive control means M8
7, the variable valve timing mechanism M
7 is further driven toward a predetermined advance position within the engine stop time according to the driving reaction force of the intake valve M5 or the exhaust valve M6.

According to a third aspect of the present invention, the predetermined advance position suitable for starting is set to be more advanced than the advance position at the time of the ignition switch-off operation. That is, the return time calculating means M13 of the delay time calculating means M9 determines the return time required to shift to the predetermined retard position based on the valve advance amount at the time of the ignition switch OFF operation detected by the operating state detecting means M12. Calculate.

Further, the engine stop time calculating means M14 of the delay time calculating means M9 is a time required from the interruption of the battery power supply to the stop of the engine based on the engine speed at the time of the ignition switch off operation detected by the operating state detecting means M12. Calculate the engine stop time. The adding means M16 calculates the delay time by adding the engine stop time to the return time. The drive control means M8 drives the variable valve timing mechanism M7 toward a predetermined advance position suitable for starting using the delay time. However, since the delay time is obtained by adding the engine stop time to the return time, the variable valve timing mechanism M7 is driven by a portion corresponding to the engine stop time to a position further advanced from a predetermined advance position. When the delay time has elapsed, the delay cutoff means M11 cuts off the battery power M10. Therefore, the drive control means M8
, The driving force of the variable valve timing mechanism M7 is lost, and the variable valve timing mechanism M7
Alternatively, it is returned to a predetermined advance position within the engine stop time due to the driving reaction force of the exhaust valve M6.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the valve timing control device for an internal combustion engine according to each invention described above is embodied in a gasoline engine will now be described in detail with reference to FIGS.

FIG. 3 is a schematic configuration diagram showing a valve timing control device for an internal combustion engine in this embodiment. The engine 1 as an internal combustion engine having a plurality of cylinders includes a piston 3 that is vertically movable within a cylinder 2 of each cylinder, and a combustion chamber 4 is provided above the piston 3. Each combustion chamber 4 is provided with a spark plug 5. In addition, each combustion chamber 4 is provided with an intake passage 6 and an exhaust passage 7 that communicate with each other through an intake port 6a and an exhaust port 7a. And the intake port 6a
The exhaust port 7a is provided with an intake valve 8 and an exhaust valve 9 for opening and closing, respectively. The intake valve 8 and the exhaust valve 9 are driven by rotation of an intake camshaft 10 and an exhaust camshaft 11. At one end of each of the camshafts 10, 11, an intake-side timing pulley 12 and an exhaust-side timing pulley 13 are provided, respectively. Furthermore, each timing pulley 12, 13
Are drivingly connected to a crankshaft (not shown) via a timing belt 14.

Therefore, when the engine 1 is operating, rotational power is transmitted from the crankshaft to the respective camshafts 10 and 11 via the timing belt 14 and the respective timing pulleys 12 and 13. The valve 8 and the exhaust valve 9 are driven to open and close. Further, the intake valve 8 and the exhaust valve 9 are synchronized with the rotation of the crankshaft, that is, in synchronization with a series of four strokes of an intake stroke, a compression stroke, an explosion / expansion stroke, and an exhaust stroke, at a predetermined opening / closing timing. Driven. In addition, fuel injectors 16 are provided in the vicinity of the intake ports 6a of the respective cylinders.

In the middle of the intake passage 6, there is provided a throttle valve 17 which opens and closes in response to operation of an accelerator pedal (not shown). When the throttle valve 17 is opened and closed, the amount of outside air taken into the intake passage 6, that is, the amount of intake air is adjusted. Further, a surge tank 18 for smoothing intake pulsation is provided downstream of the throttle valve 17. In the vicinity of the throttle valve 17, a throttle sensor 72 for detecting the throttle opening TA is provided.
Further, the temperature of the cooling water (cooling water temperature)
A water temperature sensor 75 for detecting THW is provided.

An ignition signal distributed by a distributor 21 is applied to each ignition plug 5. The distributor 21 has a built-in rotor (not shown) connected to the exhaust-side camshaft 11 and rotated in synchronization with rotation of the crankshaft. Distributor 21
Is provided with a rotation speed sensor 76 as rotation speed detecting means for detecting the rotation speed NE of the engine 1 (engine rotation speed) NE from the rotation of the rotor. Further, a cylinder discrimination sensor 77 for detecting a crank angle reference position GP of the engine 1 at a predetermined ratio according to the rotation of the rotor is attached to the distributor 21. In this embodiment, assuming that the crankshaft makes two rotations in a series of four strokes of the engine 1, the rotation speed sensor 76 detects the crank angle at a rate of 30 ° CA per pulse. The cylinder angle sensor 77 detects the crank angle at a rate of 360 ° CA per pulse.

In addition, in this embodiment, a variable valve timing mechanism (hereinafter simply referred to as “VVT”) which is hydraulically driven to change the opening / closing timing of the intake valve 8 is provided on the intake side timing pulley 12 to make the opening / closing timing of the intake valve 8 variable. 25) are provided.

Next, the configuration of the VVT 25 and the like in this embodiment will be described in detail with reference to FIGS.
4 to 8 are sectional views showing the configuration of the VVT 25 and the like. The journal 10a of the camshaft 10 on the intake side includes a cylinder head 26 of the engine 1 and a bearing cap 27.
And is rotatably supported between them. At one end of the camshaft 10, a VVT 25 is provided integrally with the timing pulley 12. The journal 10a is formed with two journal grooves 31 and 32 extending along the outer periphery. The cylinder head 26 and the bearing cap 27 are provided with a head oil passage 33 extending therethrough. In this embodiment, as shown in FIG. 3, an oil pan 28, an oil pump 29, an oil filter 30, and the like constitute a lubrication system of the engine 1. When the oil pump 29 is driven in conjunction with the operation of the engine 1, lubricating oil is sucked up from the oil pan 28 and discharged from the oil pump 29. After the discharged lubricating oil passes through the oil filter 30, it is supplied to the head oil passage 33 with a predetermined pressure.

A timing pulley housing 34 is provided at the tip of the camshaft 10. The timing pulley housing 34 includes the timing pulley 12 and a cover 35 attached so as to cover one side surface of the timing pulley 12 and the tip of the camshaft 10. The timing pulley 12 has a substantially disk shape, a plurality of external teeth 36 formed on the outer periphery thereof, and a boss 3 in the center.
7 are formed. The timing pulley 12 is mounted by its boss 37 so as to be rotatable relative to the camshaft 10. The timing belt 14 described above is mounted on the external teeth 36, and the timing pulley housing 34 is drivingly connected to the crankshaft via the belt 14. On the other hand, the cover 35 has a bottomed cylindrical shape, a flange 38 is formed on the outer periphery thereof, and a communication hole 39 is formed in the center of the bottom. Further, a plurality of internal teeth 35 a are formed on the inner periphery of the cover 35. Cover 35
A plurality of bolts 40 and pins 4
1 is fixed to one side surface of the timing pulley 12. Further, a lid 42 is detachably attached to the communication hole 39. Then, the timing pulley 12 and the cover 35
A space surrounded by the above is a housing space 43 inside the timing pulley housing 34.

In the housing space 43, a cylindrical inner cap 44 is fastened to a tip end of the camshaft 10 by a hollow bolt 45 and is prevented from rotating by a pin 46. The peripheral wall 44a of the inner cap 44 is mounted so as to enclose the boss 37 of the timing pulley 12, and the two 12, 37 are relatively rotatable. A plurality of external teeth 44b are formed on the outer periphery of the peripheral wall 44a of the inner cap 44.

A ring gear 47 is interposed between the timing pulley housing 34 and the camshaft 10, and the ring gear 47 connects the two 34 and 10. That is, the ring gear 47 has an annular shape, and is accommodated in the accommodation space 43 of the timing pulley housing 34 so as to be able to reciprocate along the axial direction of the camshaft 10. This ring gear 47 has a plurality of teeth 4 provided on its inner and outer circumferences.
Both 7a and 47b are helical teeth, and are rotatable relative to the camshaft 10 by moving in the axial direction. The inner teeth 47 a of the ring gear 47 mesh with the outer teeth 44 b of the inner cap 44, and the outer teeth 47 b of the ring gear 47 mesh with the inner teeth 35 a of the cover 35. Therefore, the timing pulley housing 34
Is driven to rotate, the timing pulley housing 34 and the inner cap 44 connected by the ring gear 47 are rotated integrally, and the camshaft 10 is further driven to rotate integrally with the timing pulley housing 34.

In the housing space 43, a first hydraulic chamber 48 is formed between one axial end of the ring gear 47 and the bottom wall of the cover 35. Similarly, in the accommodation space 43, the other end in the axial direction of the ring gear 47 and the timing pulley 1
2, a second hydraulic chamber 49 is formed.

Here, in order to supply hydraulic pressure to the first hydraulic chamber 48 with lubricating oil, a first shaft oil passage 50 extending along the center of the camshaft 10 is formed in the camshaft 10. The distal end side of the shaft oil passage 50 communicates with the first hydraulic chamber 48 through a center hole 45 a of the hollow bolt 45. The shaft oil passage 50 communicates with the journal groove 31 through an oil hole 51 extending in a substantially radial direction of the camshaft 10. In the vicinity of the oil hole 51, a ball 52 for partitioning the shaft oil passage 50 is provided in the middle of the first shaft oil passage 50. The oil hole 51 is formed by the ball 52 in the shaft oil passage 5.
Through the 0 and the center hole 45a, it communicates with only the first hydraulic chamber 48. On the other hand, in order to supply hydraulic pressure to the second hydraulic chamber 49 with lubricating oil, the camshaft 10
Is formed with a second shaft oil passage 53 extending parallel to the first shaft oil passage 50. Also, the camshaft 10
An oil hole 54 that opens to the outer periphery and communicates with the second shaft oil passage 53 is formed at the front end of the oil passage 54. Furthermore,
An oil hole 55 is formed in a part of the boss 37 of the timing pulley 12 to allow the oil hole 54 to communicate with the second hydraulic chamber 49. The base end of the second shaft oil passage 53 communicates with the journal groove 32.

In the above configuration, the oil pan 2
8, oil pump 29, oil filter 30, etc., head oil passage 33, oil hole 51, first shaft oil passage 5
The hydraulic pressure supply system for supplying the hydraulic pressure to the first hydraulic chamber 48 of the VVT 25 is constituted by the 0, the center hole 45a, and the like. Similarly, an oil pan 28, an oil pump 29, an oil filter 30, etc.
Shaft oil passage 53 and oil holes 54, 55
A hydraulic supply system for supplying hydraulic pressure to the second hydraulic chamber 49 at T25 is configured. Here, in the middle of each hydraulic supply system leading to the head oil passage 33, each hydraulic chamber 4 of the VVT 25 is provided.
An electromagnetically controlled oil control valve (OCV) 56 for electrically controlling the supply of hydraulic pressure as a driving force to the motors 8 and 49 is provided. This OCV56,
As shown in FIG. 3, the oil pan 28, the oil pump 2
9. Connected to the oil filter 30.

Next, the OCV 56 will be described in detail. FIG.
As shown in FIGS. 7 and 8, the OCV 56 includes a sleeve 57, a spool 58, and a solenoid 59. The sleeve 57 includes a supply port 60, a first discharge port 61, a second discharge port 62, and a common drain port 66. The supply port 60 is connected to the head oil passage 3
3 and connected to the oil pump 29. Further, the first discharge port 61 communicates with one of the journal grooves 31 through an oil hole 63 formed in the bearing cap 27. The second discharge port 62 communicates with the other journal groove 32 through an oil hole 64 also formed in the bearing cap 27. The common drain port 65 communicates with the oil pan 28 via an oil hole 65 also formed in the bearing cap 27.

A spring 6 is provided on the left side of the spool 58.
The spool 58 is biased by the biasing force of the spring 67 so that the spool 58 can always move to the right. The spool 58 is slidably disposed in the sleeve 57 in the left-right direction in FIG. Two annular concave portions 69 and 70 are formed on the outer periphery of the spool 58 at predetermined intervals.

On the right side of the OCV 56, a solenoid 59 is provided.
Are connected. The excitation of the solenoid 59 is controlled by an excitation current from an electronic control unit (hereinafter simply referred to as ECU) 80 described later.
The spool 58 reciprocates based on the magnitude of the exciting current from the ECU 80.

For example, when the solenoid 59 is demagnetized (duty ratio = 0%), the spool 58 moves to the right by the urging force of the spring 67 and stops at the position shown in FIG. Then, the first discharge port 61
Is connected to the common drain port 66, and the oil hole 63 is connected to the oil pan 28 via the oil hole 65. This oil hole 6
The connection amount between the oil pan 3 and the oil pan 28 is maximum (100%). On the other hand, the second discharge port 62 is connected to the supply port 60.
, And the oil hole 64 is connected to the oil pump 29. The connection amount between the oil hole 64 and the oil pump 29 is maximum (100%).

Therefore, as shown in FIG.
V56 through the oil passage 64, the journal groove 32, the second shaft oil passage 53, and the oil holes 54 and 55 to the second hydraulic chamber 4
9. The lubricating oil in the first hydraulic chamber 48 is supplied to the first shaft oil passage 50, the oil hole 63, the first discharge port 6.
1 and the oil pan 28 through the common drain port 66
Is discharged. Therefore, when the lubricating oil pressure supplied to the second hydraulic chamber 49 is applied to the other end of the ring gear 47, the ring gear 47 is axially moved against the lubricating oil remaining in the first hydraulic chamber 48. While the camshaft 10 is twisted in the opposite direction. As a result,
The relative position of the camshaft 10 and the timing pulley housing 34 in the rotation direction is changed, and the intake valve 8
Opening / closing timing is retarded. That is, FIG.
As shown in FIG. 1A, the opening and closing of the intake valve 8 is delayed, and the intake valve 8 is changed to a direction in which the valve overlap in the intake stroke is eliminated. As described above, when the hydraulic pressure is applied to the second hydraulic chamber 49, the ring gear 47 is moved as a stroke end to a position close to the cover 35 as shown in FIG. , That is, the position where the advance amount is zero.

When the solenoid 59 is excited by the maximum exciting current (duty ratio = 100%), the spool 58 moves to the left against the urging force of the spring 67 and stops at the position shown in FIG. It has become. Then, the first discharge port 61 is connected to the supply port 60, and the oil hole 63 is connected to the oil pump 29. The connection amount between the oil hole 63 and the oil pump 29 is maximum (100%). On the other hand, since the second discharge port 62 is connected to the common drain port 66, the oil hole 64 is connected to the oil pan 28. The connection amount between the oil hole 64 and the oil hole 65 is maximum (100%). Accordingly, as shown in FIG. 6, lubricating oil is supplied from the OCV 56 to the first hydraulic chamber 48 through the oil hole 63, the journal groove 31, the oil hole 51, the first shaft oil passage 50, and the center hole 45a. or,
The lubricating oil in the second hydraulic chamber 49 is supplied to the second shaft oil passage 5
3. The oil is discharged to the oil pan 28 via the oil hole 64, the second discharge port 62, the common drain port 66, and the oil hole 65.

Accordingly, when the oil pressure of the lubricating oil supplied into the first hydraulic chamber 48 is applied to one end of the ring gear 47, the ring gear 47 is connected to the lubricating oil remaining in the second hydraulic chamber 49 and the camshaft 10 and the inner shaft. The camshaft 10 is rotated while being moved in the axial direction against the reaction force from the intake valve 8 transmitted to the helical teeth via the cap 44 while being moved in the axial direction. As a result, the relative position of the camshaft 10 and the timing pulley housing 34 in the rotation direction is changed, and the opening / closing timing of the intake valve 8 is advanced. That is, as shown in FIG. 11B, the opening and closing of the intake valve 8 is advanced, and the valve overlap between the intake valve 8 and the exhaust valve 9 in the intake stroke is changed to a direction in which the valve overlap increases. Thus, by supplying the hydraulic pressure to the first hydraulic chamber 48,
As shown in FIG. 6, the ring gear 47 is moved to a position close to the timing pulley 12 as its stroke end, and the stroke end becomes the position on the maximum advance side.

Further, in this embodiment, when the solenoid 59 is excited with an exciting current corresponding to a duty ratio of about 28% to 70%, the spool moves in proportion to the magnitude of the exciting current. At this time, as shown in FIG. 8, although the amount of connection varies depending on the amount of movement of the spool 58,
The supply port 60 is provided with first and second discharge ports 61 and 62.
Are connected at the same time. Similarly,
Although the amount of connection varies depending on the amount of movement of the spool 58, the common drain port 66 is connected to the first and second discharge ports 61 and 62 at the same time.

At this time, the lubricating oil supplied from the supply port 60 is discharged to the common drain port 66, but the lubricating oil can also be supplied to the oil holes 63 and 64. Accordingly, lubricating oil is supplied to the first hydraulic chamber 48 and the second hydraulic chamber 49, and the lubricating oil can simultaneously generate hydraulic pressure in the first hydraulic chamber 48 and the second hydraulic chamber 49. It has become.

When the duty ratio is 28% or less, the spool 58 stops at the position shown in FIG. 5 as described above, and when the duty ratio is 70% or more, the spool 58 It stops at the position shown in FIG.

FIG. 9A shows the amount of movement of the spool 58 moved by the exciting current based on the duty ratio. A change in the amount of movement of the spool 58 changes the amount of connection between the supply port 60 and the first and second discharge ports 61 and 62. When lubricating oil is supplied to the first hydraulic chamber 48 and the second hydraulic chamber 49 due to the change in the amount of movement of the spool 58, the change in the hydraulic pressure in the hydraulic chambers 41 and 42 is shown in FIG. .

The first hydraulic chamber 48 and the second hydraulic chamber 4
FIG. 9C shows a characteristic indicating whether the ring gear 47 at that time moves to the advance side or the retard side due to the change of the oil pressure in the cylinder 9. When the duty ratio is 55% or less, the ring gear 47 moves to the retard side (the first hydraulic chamber 48 side). This is because while the hydraulic pressure is applied to the first and second hydraulic chambers 48 and 49, respectively,
The reason for this is that the hydraulic pressure inside the first hydraulic chamber 48 is higher than the hydraulic pressure inside the first hydraulic chamber 48 and the thrust force of the ring gear 47. Here, when the duty ratio is between 48% and 55%, the ring gear 47 moves to the retard side due to the hydraulic pressure of the second hydraulic chamber 49 even though the hydraulic pressure of the first hydraulic chamber 48 is larger. The reason is that the thrust force generated in the ring gear 47 is larger than the pressure difference between the hydraulic pressures of the hydraulic chambers 48 and 49 on both sides.

When the duty ratio is equal to or greater than 60%, the ring gear 47 moves to the advance side (the second hydraulic chamber 49 side). This is because the hydraulic pressure is applied to the first and second hydraulic chambers 48 and 49, respectively, but the hydraulic pressure in the first hydraulic chamber 48 is higher than the hydraulic pressure in the second hydraulic chamber 49. It is.

Further, when the duty ratio is set to 55% to 60%, the ring gear 47 does not move to either the advance side or the retard side, and stops at that position. At this time, the hydraulic pressure in the first hydraulic chamber 48 is higher than the hydraulic pressure in the second hydraulic chamber 49. This difference hydraulic pressure balances the thrust force of the ring gear 47, and stops the ring gear 47.

The VVT 25 is configured as described above. By driving the VVT 25, the opening / closing timing of the intake valve 8, that is, the valve overlap between the intake valve 8 and the exhaust valve 9 is reduced as shown in FIG. ) Can be continuously and arbitrarily changed between the state at the time of maximum retardation shown in FIG. 11) and the size at the time of maximum advancement shown in FIG.

As shown in FIG. 3, in this embodiment, in order to detect the actual rotation angle of the intake-side camshaft 10, that is, the cam rotation angle θCAM at a predetermined rate, the cam rotation angle sensor 78 is used. Is provided. That is, the cam rotation angle sensor 78 detects the actual cam rotation angle θCAM when the rotation phase of the camshaft 10 is changed to the advance side or the retard side by the operation of the VVT 25 as the advance amount. In addition, in this embodiment, the oil filter 3 is provided in a hydraulic supply system for supplying a drive hydraulic pressure to the VVT 25.
0 and the OCV 56, the oil temperature THO
An oil temperature sensor 79 is provided as an oil temperature state detecting means for directly detecting the oil temperature.

As shown in FIG. 3, each injector 16, igniter 22, and OCV 56 are electrically connected to an electronic control unit (hereinafter, simply referred to as "ECU") 80. Controlled. In this embodiment, the ECU 80 constitutes delay time calculating means, drive control means, and delay cutoff means. In this embodiment, the delay time calculating means further includes an operating state detecting means, a return time calculating means, an engine stop time calculating means, and a subtracting means. EC
U80 is also configured as a means for detecting on / off of the switch SW. The ECU 80 includes the throttle sensor 74, the water temperature sensor 75, and the rotation speed sensor 7.
6. The cylinder discrimination sensor 77, the cam rotation angle sensor 78, and the oil temperature sensor 79 are connected respectively. The ECU 80 suitably controls the driving of each injector 16, the igniter 22, and the OCV 56 based on the output signals from the sensors 74 to 79 and the like. Further, in this embodiment, an operating state detecting means for detecting an operating state of the engine 1 necessary for controlling the valve timing by a throttle sensor 74, a rotation speed sensor 76, a cam rotation angle sensor 78, an oil temperature sensor 79 and the like. Is configured.

Next, the electrical configuration of the ECU 80 will be described with reference to the block diagram of FIG. The ECU 80 includes a central processing unit (CPU) 81, a read-only memory (ROM) 82 in which a predetermined control program and the like are stored in advance,
A random access memory (RAM) 83 for temporarily storing the calculation results of the PU 81 and the like, a backup RAM 84 for storing previously stored data, and the like are provided. The ECU 80 controls the external input circuit 8 including the analog / digital converter for each of the members 81 to 84.
5 and an external output circuit 86 are connected by a bus 87.

The external input circuit 85 includes the throttle sensor 74, water temperature sensor 75, rotation speed sensor 76, cylinder discrimination sensor 77, cam rotation angle sensor 78, and oil temperature sensor 7.
9 are connected to each other. On the other hand, the external output circuit 8
6, each injector 16, igniter 22 and OC
V56 are connected respectively.

The CPU 81 reads the detection signals of the sensors 74 to 79 and various sensors (not shown) input through the external input circuit 85 as input values and stores them in a predetermined area of the RAM 83. Also, the CPU 81
Are used to execute fuel injection amount control, ignition timing control, idle speed control, valve timing control, etc., based on input values read from the sensors 74 to 79 and various sensors (not shown). And the OCV 56 and the like are suitably controlled.

In addition to the above configuration, in order to make the valve timing suitable for idling after the switch SW is turned off, a circuit configuration is adopted in which power is applied to each circuit even after the key switch is turned off. ing.

That is, the external output circuit 86 is connected to the base terminal of the transistor TR. The emitter terminal of the transistor TR is connected to the input terminal of the power holding circuit 88, and the collector terminal is grounded. The other input terminal of the power supply holding circuit 88 is connected to a power supply circuit 89 including a battery via a switch SW. A resistor R1 is connected between the switch SW and the power holding circuit 88, and a negative terminal of the resistor R1 is grounded via a resistor R2. or,
The output terminal of the power holding circuit 88 is connected to the power circuit 89. The power supply circuit 89 is connected to various electric circuits mounted on the vehicle and supplies power stably. The power supply circuit 89 is operated by the High signal from the power supply holding circuit 88 and is stopped by the Low signal.

The power holding circuit 88 is provided with a switch SW.
Is turned on, a High signal is output from the output terminal. When a drive signal from the external output circuit 86 is output to the transistor TR, the transistor TR operates and a High signal is output from the output terminal of the power holding circuit 88. The power holding circuit 88 is described in Japanese Patent Application Laid-Open No. Sho 60-166705, page 5, upper left column, line 19 to upper right column, line 12.
This can be realized by an R gate and a relay.

Next, among the various processing contents executed by the ECU 80, the processing contents of the valve timing control will be described. FIG. 16 is a flowchart showing a “valve timing control routine” executed by the ECU 80 to change the opening / closing timing of the intake valve 8 when the switch SW is turned off from the time of operation of the engine 1. The processing of this routine is executed when the switch SW is turned off.

That is, when the switch SW is turned off,
The fact that the switch SW has been turned off is recorded in the RAM 83, and the ECU 80 determines whether or not the switch SW is on in an interrupt routine that is executed at predetermined time intervals, and shifts to this valve timing control routine. Therefore, the ECU 80 serves as a means for detecting the operation of turning off the switch SW.

Now, when the processing shifts to this routine,
First, in step 101, a drive signal is output to the transistor TR via the external output circuit 86. As a result,
As in the case where the transistor TR operates and the switch SW is turned on, the output terminal of the power holding circuit 88
The igh signal is output, and the power supply circuit 89
It continues to operate by the High signal from. Next, in step 102, immediately before the switch SW is turned off, R
Based on the detection values of the sensors 76, 78, and 79 stored in the AM 83, input values such as the engine speed NE, the cam rotation angle θCAM, and the oil temperature THO are read. Subsequently, in step 103, a return time T1 based on the cam rotation angle θCAM read this time, a return correction coefficient P based on the rotational speed NE, a return correction coefficient Q based on the oil temperature THO, and a control based on the rotational speed NE. The engine stop time T2 is calculated.

The return time T1 is determined by the switch SW
This is the time required to shift from the valve timing at the time of the OFF operation to the valve timing suitable for starting (in this embodiment, the maximum retardation (the advance amount is zero)), and the calculation is as shown in FIG. Is performed with reference to a map including the cam rotation angle (advance angle) and the return time. This map is stored in the ROM 82 in advance. In this map, as the cam rotation angle θCAM (advance angle) increases, the return time T1 is set to have a proportional relationship that increases with the cam rotation angle θCAM, and these values are obtained in advance by experiments or the like.

The calculation of the return correction coefficient P is as shown in FIG.
As shown in (1), this is performed by referring to a map composed of the rotational speed NE and the return correction coefficient P. This map is stored in ROM 82 in advance.
Is stored in In this map, the return correction coefficient P is set so as to gradually decrease as the rotational speed NE increases.

The return correction coefficient P is equal to the engine speed NE.
This is a coefficient for correcting the influence of the change in the driving force on the VVT 25 due to the above. The return of the VVT 25 due to the driving reaction force from the intake valve 8 is promoted as the engine speed NE increases, so that the return time of the VVT 25 is shortened. That
When an engine-driven oil pump is used, the lubricating oil pressure increases as the engine speed NE increases to a certain extent, and the operating speed of the VVT 25 increases, so that the return time is shortened. Is set to gradually decrease as the value increases. Further, the calculation of the return correction coefficient Q is performed with reference to a map composed of the oil temperature THO and the return correction coefficient Q as shown in FIG. This map is stored in the ROM 82 in advance. In this map, as the oil temperature THO increases,
The return correction coefficient Q is set to increase. The return correction coefficient Q is a coefficient for correcting a change in the driving force to the VVT 25 due to the oil temperature THO. As the oil temperature THO increases, the viscosity of the lubricating oil decreases, and the hydraulic pressure as the driving force decreases. Since the time increases, it is set to increase as the oil temperature THO increases. The engine stop time T2 represents the time from when the power is cut off until the engine is completely stopped, and the calculation is made up of the engine speed NE and the engine stop time T2 as shown in FIG. This is done with reference to the map. This map is stored in the ROM 82 in advance. In this map,
The engine stop time T2 is set to gradually increase as the rotational speed NE increases. This is because the higher the engine speed, the greater the rotational inertia and the longer it takes to stop.

In step 104, the delay time T is calculated by the following formula based on the determined return time T1, return correction coefficient P, return correction coefficient Q, and engine stop time T2.

T = P * Q * T1-T2 That is, the delay time T is obtained by subtracting the engine stop time T2 from the value obtained by multiplying the return time T1 by the return correction coefficients P and Q, respectively. The delay time T is obtained as a delay time necessary and sufficient for the valve timing to shift to the maximum retardation time after the switch SW is turned off and before the engine is stopped. In this embodiment, the maximum retardation is set to zero (the advance amount is zero). However, the present invention is not limited to this. Any advance position at start-up may be used.

Then, at step 105, the time of the delay time is counted, and the routine goes to step 106. At step 106, the ECU 80 controls the VVT 25 to the maximum retard side by controlling the opening of the OCV 56. In step 107, it is determined whether or not the delay time T has elapsed. If the delay time T has not elapsed, the process returns to step 106. When the delay time T has elapsed, the output of the drive signal to the transistor TR via the external output circuit 86 is stopped in step 108. As a result, the transistor TR is turned off.
The ow signal is output to the power supply stabilization circuit 89, and the power supply circuit 89 is cut off.

[0060] Even after the power supply circuit 89 is cut off, the engine 1 continues to operate during the engine stop time T2. Then, after the power supply circuit 89 is cut off,
Although the control signal from the ECU 80 to the OCV 56 is no longer output, since the OCV 56 is moved rightward in FIG. 5 by the spring 67, the hydraulic pressure is continuously supplied to the second hydraulic chamber 49. As a result, the engine 1 is stopped in a state where the stroke end of the ring gear 47 is at the maximum retard side. Therefore, at the start, the engine is started on the optimal maximum retard side, and the startability can be improved.

In this embodiment, even after the power supply circuit 89 is shut off, the valve timing is adjusted to the maximum retard side using the engine stop time T2.
Unlike the conventional case, the delay time can be set to the minimum necessary time.

From the above, in this embodiment, step 103 corresponds to the return time calculating means for calculating the return time T1, and also corresponds to the engine stop time calculating means for calculating the engine stop time T2. Further, in this embodiment, step 103 corresponds to a correction coefficient calculating means for calculating a return correction coefficient Q based on the oil temperature at the time when the switch SW is turned off and a return correction coefficient P based on the engine speed. In step 104, P * Q * T
This corresponds to subtraction means for subtracting the engine stop time T2 from 1. Further, step 104 corresponds to a correction return time calculating means for calculating a correction return time P * Q * T1 based on the correction coefficients P and Q at the return time T1. Steps 103 and 104 constitute a delay time calculating means. Step 106 corresponds to the drive control means.
Steps 107 and 108 constitute the delay control means.

Next, a second embodiment will be described with reference to FIG. This embodiment is an embodiment in which the preferred advance position at the time of starting is set, and the valve timing at the time of the OFF operation of the switch SW is set to the advance side from the first embodiment. In this embodiment, only different points from the first embodiment will be described for convenience of description, and the description of the same configuration will be omitted.

FIG. 17 is a flowchart showing a "valve timing control routine" executed by the ECU 80 to change the opening / closing timing of the intake valve 8 when the switch SW is turned off during the operation of the engine 1. The processing of this routine is executed when the switch SW is turned off.

This flowchart is different from the first embodiment in that step 111 is substituted for step 104 and step 112 is substituted for step 106 in the first embodiment.

In step 111, step 10
The delay time T is calculated by the following formula based on the return time T1, the return correction coefficient P, the return correction coefficient Q, and the engine stop time T2 obtained in Step 3.

T = P * Q * T1 + T2 This delay time T is a delay time sufficient and sufficient for the valve timing to shift to a suitable advanced position at the time of starting after the switch SW is turned off and before the engine is stopped. Is required.

That is, when the preferred advance position at the time of starting is set to be more advanced than the valve timing at the time of the OFF operation of the switch SW, the valve timing is advanced during P * Q * T1. Even if the valve timing shifts to the retard side again due to the driving reaction force from the intake valve 8 during the time T2 after the power is cut off, P * Q * T
The delay time T is calculated by adding the time T2 to the value of 1.

The return time T1 is determined by the switch SW
This is the time required to shift from the valve timing at the time of the OFF operation to the valve timing suitable for startup (in this embodiment, the predetermined advance position (advance amount ≠ 0)).

Then, at step 105, the time of the delay time is counted, and at step 112, the ECU 80
Is controlled by controlling the opening of the OCV 56 so that the VVT 25
Is controlled to a suitable advanced position at the time of starting. Then, when the delay time T has elapsed in step 107, the output of the drive signal to the transistor TR via the external output circuit 86 is stopped in step 108. As a result, since the transistor TR is turned off, a Low signal is output from the power holding circuit 88 to the power circuit 89, and the power circuit 89 is cut off.

Even after the power supply circuit 89 is cut off, the engine 1 continues to operate during the engine stop time T2. Then, after the power supply circuit 89 is cut off,
The control signal from the ECU 80 to the OCV 56 is no longer output, but is moved to the right by the spring 67 of the OCV 56 as shown in FIG. Shifts to the retard side. As a result, the engine 1 is stopped while the stroke end of the ring gear 47 is at a suitable advance angle at the time of starting. Therefore, at the start, the engine is started at the optimum advance position, and the startability can be improved.

From the above, in the second embodiment, step 103 corresponds to the return time calculating means for calculating the return time T1, and the engine stop time T2
Is calculated. Step 111 corresponds to adding means for adding the engine stop time T2 from P * Q * T1. Steps 103 and 111 constitute a delay time calculating means. Step 112 corresponds to the drive control means, and steps 107 and 108 constitute the delay control means.

The present invention can be implemented as follows with a part of the configuration changed. (1) In the above embodiment, the valve overlap is adjusted by changing only the opening / closing timing of the intake valve 8 by the VVT 25 provided on the camshaft 10 on the intake side. On the other hand, the valve overlap may be adjusted by providing a VVT on the exhaust-side camshaft 11 and changing only the opening / closing timing of the exhaust valve 9 using the VVT. That is, the exhaust valve is adjusted so as to open and close in a direction in which the valve overlap is eliminated in the intake stroke.

Alternatively, a VVT is provided on each of the camshafts 10 and 11 on the intake side and the exhaust side, and the respective VVTs are provided.
By changing the opening / closing timing of the intake valve 8 and the exhaust valve 9 respectively, the opening and closing of the intake / exhaust valve may be adjusted in such a manner that the valve overlap is eliminated in the intake process.

(2) In the above embodiment, the oil temperature sensor 79 for directly detecting the oil temperature THO in the hydraulic pressure supply system is provided as the oil temperature state detecting means. On the other hand, the oil temperature sensor 79 is omitted, and instead, the water temperature sensor 75 is also used as oil temperature state detecting means, and the cooling water temperature THW detected by the sensor 75 is used as an oil temperature equivalent value. May be used as the oil temperature substitute value. As a result, since there is no need to provide an oil temperature sensor, costs can be reduced.

(3) In the above embodiment, the return correction coefficient P,
Although the return time is multiplied by Q, the delay time T may be obtained by subtracting the engine stop time T2 from the return time T1 without multiplying the return correction coefficients P and Q. In this case, the delay time P
Although the valve timing shifts to the maximum retard during * Q * T1, the valve timing does not further retard even if a valve driving reaction force is received during T2 thereafter.

(4) In the above embodiment, the engine stop time T2 is subtracted from the corrected return time P * Q * T1 to obtain the delay time T. However, the case where the valve timing at the time of starting is set to the maximum retarded angle is set. , The corrected return time P * Q * T1 may be used as the delay time without subtracting the engine stop time T2.

(5) In the above-described embodiment, the VVT 25 is embodied as a hydraulic drive type. However, the VVT 25 may be embodied as a VVT which can obtain an arbitrary valve timing by applying a twist to a camshaft by a step motor. . In the technology of driving the valve timing to the retard side or the advance side at the time of starting, there is a problem that since the starter is operating at the start, the voltage is reduced, and it is difficult to control the step motor to the retard side or the advance side. However, there is an advantage that such a problem does not occur if a delay time for delaying the cutoff of the battery power is provided when the switch is turned off and the step motor is driven and controlled using the delay time.

If the valve timing does not shift due to the driving reaction force from the intake / exhaust valve in the step motor type, the valve timing does not change during the engine stop time T2. Irrespective of the above, the delay time T may be P * Q * T1.

In addition, the technical ideas grasped from the above-described embodiments other than the claims of the present invention will be described below together with the effects. (A) In the second aspect, when the hydraulic pressure operated VVT is used, the delay time calculating means includes a return correction coefficient based on the temperature of the liquid at the time of the ignition switch-off operation detected by the operating state detecting means. Correction coefficient calculating means for calculating a return correction coefficient based on the engine speed; and a correction return time for calculating a correction return time based on the correction coefficient calculated by the correction coefficient calculation means based on the return time calculated by the return time calculation means. A valve timing control device for an internal combustion engine, comprising: arithmetic means; and wherein the subtraction means subtracts the engine stop time from the corrected return time.

In this control device, according to the engine speed,
Further, the corrected return time can be obtained according to the liquid temperature, and the delay time T can be obtained with higher accuracy. (B) The valve timing control device for an internal combustion engine according to claim 1 or 2, wherein the delay time calculation means calculates a time required to drive from the valve timing at the time of the switch-off operation to the valve timing of the maximum delay. .

With this control device, the effects described in claim 1 can be obtained for an engine whose valve timing at the maximum retardation is suitable at the time of starting.

[0083]

As described above in detail, according to the first aspect of the present invention, in a valve timing control apparatus capable of setting an arbitrary valve timing, even if the valve timing is an arbitrary valve timing at the time of a switch-off operation, the starting is performed. Thus, there is an effect that a smooth start can be surely performed without wasting up to the optimal valve timing.

Further, according to the second aspect of the present invention, the valve timing is adjusted to the retard side by utilizing the time during which the engine is stopped even after the battery power is cut off. It can be.

According to the third aspect of the present invention, even when the preferred advance position at the time of starting is set to an advance side from the valve timing at the time of turning off the ignition switch, even after the battery power is cut off, The valve timing can be adjusted to the advanced side by utilizing the time during which the engine is stopped.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram showing a basic conceptual configuration of the invention of claim 1;

FIG. 2 is a conceptual configuration diagram showing a basic conceptual configuration of the invention of claim 2;

FIG. 3 is a schematic configuration diagram showing a valve timing control device for an internal combustion engine according to a first embodiment of the invention.

FIG. 4 is a sectional view showing a configuration of a VVT and the like.

FIG. 5 is a sectional view showing the structure of the OCV.

FIG. 6 is a sectional view showing a configuration of a VVT and the like.

FIG. 7 is a sectional view showing the structure of the OCV.

FIG. 8 is a sectional view showing the structure of the OCV.

9A is a characteristic diagram of the amount of movement of the spool with respect to the duty ratio, FIG. 9B is a characteristic diagram of the first hydraulic chamber and the second hydraulic chamber with respect to the duty ratio, and FIG. FIG. 4 is a characteristic diagram showing a moving direction of the image.

FIG. 10 is a block diagram showing a configuration of an ECU and the like.

FIG. 11 is an explanatory diagram showing a valve overlap between an intake valve and an exhaust valve.

FIG. 12 is a map showing a relationship between a cam rotation angle and a return time T1.

FIG. 13 is a map showing the relationship between the engine speed and the return correction coefficient P.

FIG. 14 is a map showing the relationship between the oil temperature and the return correction coefficient Q.

FIG. 15 is also the engine speed and the engine stop time T.
2 is a map showing a relationship with the second map.

FIG. 16 is a flowchart of a valve timing control routine.

FIG. 17 is a flowchart of a valve timing control routine in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine as an internal combustion engine, 4 ... Combustion chamber, 6 ... Intake passage, 7 ... Exhaust passage, 8 ... Intake valve, 9 ... Exhaust valve, 25 ... Variable valve timing mechanism (VVT), 56
... OCV, 74 ... Throttle sensor, 75 ... Water temperature sensor, 76 ... Rotation speed sensor, 78 ... Rotation angle sensor, 79 ...
Oil temperature sensors (74, 76, 7) as oil temperature state detecting means
8, 79 and the like constitute operating state detecting means), 80 ... ECU (80 constitutes delay time calculating means, delay breaking means and drive control means, and the delay time calculating means comprises return time calculating means And an engine stop time calculating means.) 89, power supply circuit.

Claims (3)

(57) [Claims] A variable valve timing mechanism for driving at least one of an intake valve and an exhaust valve respectively opening and closing an intake passage and an exhaust passage communicating with a combustion chamber of an internal combustion engine to arbitrarily vary a valve timing; In a valve timing control device for an internal combustion engine, comprising: a drive control means for electrically controlling a driving force with respect to a variable valve timing, when the valve timing at the time of an ignition switch-off operation is an inappropriate valve timing at the time of starting, A delay time calculating means for calculating a delay time based on a return time required to shift from a valve timing at the time of an ignition switch OFF operation to a predetermined valve timing suitable for starting, and a delay for shutting off battery power when the delay time has elapsed. And a drive control means. A valve timing control device for an internal combustion engine, wherein the variable valve timing mechanism is driven toward a valve timing suitable for starting using the delay time. 2. The variable valve timing mechanism changes a valve timing of an internal combustion engine according to a driving force supplied from the driving control means and a driving reaction force from an intake valve or an exhaust valve. The delay time calculation means includes: an operation state detection means for detecting an operation state of the internal combustion engine; and a shift to a predetermined advance position based on the valve advance amount at the time of the ignition switch off operation detected by the operation state detection means. Return time calculating means for calculating the return time required for the engine, and the engine stop time, which is the time required from the battery power cut-off to the engine stop, based on the engine speed at the time of the ignition switch-off operation detected by the operating state detecting means. Engine stop time calculating means for subtracting the engine stop time from the return time to calculate a delay time The valve timing control apparatus for an internal combustion engine according possible to claim 1, characterized in that comprises a. 3. The variable valve timing mechanism changes a valve timing of the internal combustion engine according to a driving force supplied from the driving control means and a driving reaction force from an intake valve or an exhaust valve. The delay time calculation means includes: an operation state detection means for detecting an operation state of the internal combustion engine; and a shift to a predetermined advance position based on the valve advance amount at the time of the ignition switch off operation detected by the operation state detection means. Return time calculation means for calculating the return time required for the engine, and the engine stop time, which is the time required from the battery power cut-off to the engine stop, based on the engine speed at the time of the ignition switch-off operation detected by the operating state detection means. Engine stop time calculating means for adding the engine stop time from the return time to calculate a delay time The valve timing control apparatus for an internal combustion engine according possible to claim 1, characterized in that comprises a.