JP3075126B2 - 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 apparatus for an internal combustion engine, and more particularly to a valve timing control apparatus for an internal combustion engine that controls a period during which an intake valve and an exhaust valve are simultaneously opened (valve overlap period). It concerns the device.

[0002]

2. Description of the Related Art Conventionally, a variable valve timing mechanism for changing a state in which an intake valve and an exhaust valve are simultaneously opened (valve overlap) according to an operating state of an engine has been put to practical use. FIG. 9 is a target displacement angle map in which target displacement angles of valve timing with respect to engine speed and load (intake pressure) are set.

[0003] In this map, when the engine speed is in a high speed range in a high load range, the opening / closing timing of the intake valve is set to the retard side (valve overlap is small) to enter the combustion chamber when the throttle is fully opened. Is set so as to improve the suction efficiency. In addition, when the engine speed is in the low speed range in a high load range, the opening / closing timing of the intake valve is set to the advanced side (valve overlap is large) to improve the efficiency of charging the intake air into the combustion chamber. It is set as follows.

In the middle load range, since the internal EGR causes low emission and low fuel consumption, the opening and closing timing of the intake valve is set to be advanced to the misfire limit. In the light load range, the misfire easily occurs, so that the opening / closing timing of the intake valve is always set to the retard side.

However, the variable valve timing mechanism based on the above map has the following problems. In the map of FIG. 9 , the engine speed is 2000-4000.
At rpm, when the load state changes from the high load range to the low load range, the valve timing changes from the advanced position (high load range) to the most advanced position (medium load range) and then to the retard position (low load range). Load area). Therefore, as shown by two-dot chain line in FIG. 10 (c), when decelerated from the high load region, after the valve timing is temporarily controlled to the most advanced position, retarded as the load is reduced Controlled. Therefore, the valve timing temporarily becomes excessively advanced in the low load range. That is, an operation delay occurs in the variable valve timing mechanism. In this case, since the valve overlap becomes large at a low intake pressure, misfiring or poor combustion occurs, an undershoot of the engine speed or an engine stall occurs, and the drivability deteriorates.

In order to solve this problem, the following valve timing control device has been proposed (Japanese Patent Laid-Open Publication No. Hei 6-1994).
No. 213021). According to the valve timing control device described in this publication, the vehicle speed (engine speed)
Is less than or equal to a predetermined speed (predetermined rotation speed), that is, at the time of deceleration, the variable valve timing mechanism is driven and controlled at a preset valve timing limit advance value corresponding to the vehicle speed at that time. The valve timing limit advance value is obtained by adding a limit to the advance value of the target displacement angle obtained from the engine rotational speed at that time obtained from the map of FIG. 9 and the load. In the case of deceleration, the advance value of the target displacement angle obtained from the map is restricted and set to a limited advance value smaller than the advance value of the target displacement angle.
As a result, as shown in FIG. 10 (d), can be prevented over-advancement of the valve timing by the operation delay of the variable valve timing mechanism during deceleration.

[0007]

However, the prior art described in the above publication has the following problems. At the time of deceleration, the advance value of the target displacement angle is limited, but this limited advance value is a fixed value. For example, as shown in FIG. 10 (e), the limited advance value is set to 20 ° CA, and the actual displacement angle before deceleration is 3 ° on the more advanced side than the limited advance value of 20 ° CA.
In the case of 0 ° CA, the valve timing is forcibly controlled to the retard side despite the advance request. As a result, hunting (shock) occurs and drivability deteriorates.

In order to solve this problem, it is conceivable to set the limit advance value to a high value (around 30 ° CA to 40 ° CA). However, the actual displacement angle at the start of deceleration becomes close to the most retarded angle. In such a case, similarly to the above-described related art, an operation delay occurs in the variable valve timing mechanism, which causes a misfire, poor combustion, or the like.

The present invention was made to solve the above problems, and an object in changing the valve timing during deceleration, the slow operation of the variable valve timing mechanism
While preventing, to provide a valve timing control apparatus for an internal combustion engine capable of preventing the shock at the time of changing the valve timing.

[0010]

To achieve the above object, according to an aspect of, in the invention described in claim 1, in synchronism with the rotation of the internal combustion agencies to be mounted on vehicles are driven at a predetermined timing, the combustion chamber intake passage Michi及 beauty exhaust passage path and intake valves及 beauty exhaust valves for opening and closing respectively, to continuously vary the at least one of the opening and closing timing of the intake valves及 <br/> beauty the exhaust valves communicating detection and variable valve timing Organization driven, the valve timing detection hand stage for detecting the actual displacement angle of the valve at the side of the variable valve timing Organization is disposed, an operating condition of the internal combustion institutions for operating condition detecting hands stage for the operating condition detecting hand stage
More state of the internal combustion institution when it is detected to be in the high load region or low load region, so that the valve overlap amount is small, also is detected to be in the middle load range is state of the internal combustion institutions to and a case, the target displacement angle calculating hand stage valve overlap amount calculates the target displacement angle so that the larger,
For controlling the drive of the variable valve timing mechanism to change the valve overlap amount based on the actual displacement angle detected by the valve timing detection means and the target displacement angle calculated by the target displacement angle calculation means. and drive control means, the increment changes the target displacement angle to be referred to said drive control means to be equal to or less than a predetermined value when said Bal <br/> Bed overlap amount during deceleration of the internal combustion engine is increased Internal combustion engine provided with target displacement angle changing means
The gist is the valve timing control device of Seki .

[0011] In the invention of claim 2, wherein the target displacement angle changing hands stage, the larger the deceleration degree of the internal combustion agencies, and its gist that it has a setting means for setting a small predetermined value .

[0012]

[Action] In the valve timing control apparatus for an internal combustion engine according to the invention of claim 1 having the above structure, when starting the internal combustion agencies, predetermined timing in synchronism intake valves及 beauty exhaust valves in rotation of the internal combustion agencies in is driven to open and close the intake passage Michi及 beauty exhaust communication passage leading to the combustion chamber. The variable valve timing Organization the intake valves, to change at least one of the valve timing of the exhaust valves. Valve timing detection hand stage detects an actual displacement angle of the valve to be changed. Furthermore, the operating condition detecting hands stage detects an operating state of the internal combustion agencies, detecting a target displacement angle calculating hand stage, the state of the driving state detecting hands stage by Ri internal combustion institution is in the high load region or low load region is the case were, as in the valve overlap amount is small, and when the state of the internal combustion agencies detected to be in the middle load region, the target displacement angle so that the valve overlap amount is large Is calculated. Target displacement angle change hand
Stage, increasing the valve overlap amount at the time of deceleration of the internal combustion institutions
In addition , the drive control means refers to such that the increase amount of the valve overlap amount is equal to or less than a predetermined value .
The target displacement angle is changed.

Therefore, during deceleration of the internal combustion engine, valve over
-When the overlap amount increases , the target displacement angle is changed so that the increase amount of the valve overlap amount becomes a predetermined value or less.
Is, variable valve timing Organization based on the target displacement angle after the change is driven and controlled through the drive control means. As a result, hunting shock is prevented at the time of deceleration of the internal combustion agencies.

[0014] In the valve timing control apparatus for an internal combustion engine according to the invention of claim 2, in addition to the effects of the claims 1 invention, the target displacement angle changing hands stage the larger the deceleration of the internal combustion organizations, by the setting means wherein since the predetermined value is set small, can be brought close the valve timing gradually to the target displacement angle, hunting shock is avoided in further deceleration of the internal combustion agencies.

[0015]

EXAMPLES (First Example) Hereinafter, the valve timing control apparatus for an internal combustion engine of the present invention for the first embodiment embodying the valve timing control system for a gasoline engine, referring to FIGS. 1 to 5 and 8 I will explain.

[0016] First will be described with reference to FIGS. 1 and 2 the configuration of the valve timing control device VC of the engine 10. FIG. 1 is a schematic configuration diagram showing a gasoline engine system including a valve timing control device VC of an internal combustion engine.

An engine 10 as an internal combustion engine includes a cylinder block 11 in which a plurality of cylinders are formed, and a cylinder head 1 connected to an upper portion of the cylinder block 11.
2 and a piston 13 that reciprocates up and down in each cylinder of the cylinder block 11. Further, a crankshaft 14 is connected to a lower end portion of the piston 13, and the crankshaft 14 is rotated by moving the piston 13 up and down.

A crank angle sensor 40 is provided near the crankshaft 14. The crank angle sensor 40 includes a magnetic rotor (not shown) connected to the crankshaft 14 and an electromagnetic pickup (not shown). (Not shown). Here, equiangular teeth are formed on the outer periphery of the rotor, and every time the equiangular teeth of the rotor pass in front of the electromagnetic pickup, a pulse-like crank angle signal is detected. Then, the rotation angle (crank angle) of the crankshaft 14 is detected by measuring the number of generations of the crank angle signal from the crank angle sensor 40 after the generation of the reference position signal by the cylinder determination sensor 42 described later.

The space defined by the inner wall of each cylinder block 11 and cylinder head 12 and the top of the piston 13 forms a combustion chamber 1 for burning an air-fuel mixture.
Functions as 5. At the top of the cylinder head 12, an ignition plug 16 for igniting the air-fuel mixture is provided so as to project into the combustion chamber 15. Each spark plug 1
6 is connected to the distributor 18 via a plug cord or the like (not shown). The high voltage output from the igniter 19 is supplied to the distributor 18
Thus, the fuel gas is distributed to each spark plug 16 in synchronization with the crank angle.

Further, the distributor 18 is connected to the exhaust-side camshaft 33 and is connected to the crankshaft 1.
An engine speed sensor 41 for detecting the speed of the engine 4 is provided. The engine speed sensor 41 includes a magnetic rotor (not shown) that rotates in synchronization with the crankshaft 14 and an electromagnetic pickup (not shown).
The electromagnetic pickup detects the number of rotations of the rotor, so that the number of rotations of the crankshaft 14 (engine speed N
E) will be detected. Further, the distributor 18 is provided with a cylinder discriminating sensor 42 for detecting a reference position of the crank at a predetermined ratio from the rotation of the rotor.

The cylinder block 11 is provided with a water temperature sensor 43 for detecting the temperature of the cooling water flowing through the cooling water passage (cooling water temperature). The cylinder head 12
It has an intake port 22 and an exhaust port 32. The intake port 20 is connected to the intake passage 20, and the exhaust port 32 is connected to the exhaust passage 30. The intake port 22 of the cylinder head 12 has an intake valve 2
The exhaust port 32 is provided with an exhaust valve 31.

Above the intake valve 21, an intake camshaft 2 for opening and closing the intake valve 21 is provided.
The exhaust side camshaft 33 for opening and closing the exhaust valve 31 is disposed above the exhaust valve 31. At one end of each of the camshafts 23 and 33, an intake-side timing pulley 27 and an exhaust-side timing pulley 34 are mounted.
7 and 34 are connected to the crankshaft 14 via a timing belt 35.

Therefore, when the engine 10 is operating, the camshafts 23, 3 are transmitted from the crankshaft 14 via the timing belt 35 and the timing pulleys 27, 34.
3 is transmitted to the respective camshafts 23, 33.
, The intake valve 21 and the exhaust valve 31 are opened and closed. These valves 21 and 31 are
At a predetermined opening / closing timing, in synchronization with the rotation of the crankshaft 14 and the vertical movement of the piston 13, that is, in synchronization with a series of four strokes of the engine 10 including an intake stroke, a compression stroke, an explosion / expansion stroke, and an exhaust stroke. Driven.

Further, a cam angle sensor 44 for detecting the valve timing of the intake valve 21 is provided near the intake side camshaft 23.
Reference numeral 4 denotes a magnetic rotor (not shown) connected to the intake-side camshaft 23 and an electromagnetic pickup. A plurality of teeth are formed at equal angles on the outer circumference of the magnetic rotor. For example, before the compression top dead center (TDC) of a predetermined cylinder, between 90 ° and 30 ° BTDC, the intake side cam is formed. A pulse-like cam angle signal accompanying the rotation of the shaft 23 is detected.

An air cleaner 24 is connected to the air intake side of the intake passage 20, and a throttle valve 26 which is opened and closed in conjunction with an accelerator pedal (not shown) is provided in the intake passage 20. ing. The intake air amount is adjusted by opening and closing the accelerator pedal.

In the vicinity of the throttle valve 26, a throttle sensor 4 for detecting the throttle opening TA is provided.
5 are provided. Further, a surge tank 2 for suppressing intake pulsation is provided downstream of the throttle valve 26.
5 are formed. And in the surge tank 25,
An intake pressure sensor 46 for detecting an intake pressure PW in the surge tank 25 is provided. An injector 17 for supplying fuel to the combustion chamber 15 is provided near the intake port 22 of each cylinder. Each injector 17 is an electromagnetic valve that is opened by energization,
Each injector 17 is supplied with fuel pumped from a fuel pump (not shown).

Therefore, when the engine 10 is operating, the air filtered by the air cleaner 24 is taken into the intake passage 20, and fuel is injected from each injector 17 toward the intake port 22 at the same time as taking in the air. You. As a result, an air-fuel mixture is generated at the intake port 22, and the air-fuel mixture is opened with the opening of the intake valve 21.
It is sucked into the combustion chamber 15. In the middle of the exhaust passage 30,
A catalytic converter 36 including a three-way catalyst for purifying exhaust gas is provided. In the middle of the exhaust passage 30, an oxygen sensor 4 for detecting the oxygen concentration in the exhaust gas is provided.
7 are provided.

In the gasoline engine system of this embodiment, the variable valve timing mechanism 50 (hereinafter referred to as “V”) is driven by hydraulic pressure in order to change the opening / closing timing of the intake valve 21 to change the valve overlap amount.
VT ”. ) Are arranged. This VVT50
Is the crankshaft 14 (the intake-side timing pulley 2
This is a mechanism for continuously changing the valve timing of the intake valve 21 by changing the phase of rotation of the intake side camshaft 23 with respect to the rotation of 7).

[0029] for such VVT50 system configuration will be described with reference to FIG. Here, FIG. 2 is VVT5
FIG. 5 is an explanatory diagram showing a cross section near the intake side camshaft 23 where 0 is disposed, and an entire control system of the VVT 50.

The control system of the VVT 50 includes a VVT 5
0, an oil control valve 80 (hereinafter referred to as “OCV”) for applying a driving force to the VVT 50, a cam angle sensor 44 for detecting a cam angle signal, various other sensors, and various types of sensors including the cam angle sensor 44. An electronic control unit (hereinafter, referred to as “ECU”) 70 that controls driving of the OCV 80 based on an input signal from a sensor is provided.

The VVT 50 is disposed between the intake side camshaft 23 and the intake side timing pulley 27,
The intake camshaft 23 is rotatably supported between the cylinder head 12 and the bearing cap 51. An intake-side timing pulley 27 is mounted near the tip of the intake-side camshaft 23 so as to be relatively rotatable. An inner cap 52 is attached to the tip of the intake-side camshaft 23 by a hollow bolt 53 and a pin 54. It is attached so that it can rotate integrally.

A housing 56 having a cap 55 is provided on the intake-side timing pulley 27 with bolts 57 and pins 5.
The housing 56 covers the distal end of the intake-side camshaft 23 and the entire inner cap 52. Further, on the outer periphery of the intake-side timing pulley 27, a number of external teeth 27a for mounting the timing belt 35 are formed.

The intake side camshaft 23 and the intake side timing pulley 27 are connected by a ring gear 59 interposed between the housing 56 and the inner cap 52. The ring gear 59 has a substantially annular shape, and is housed in a space S surrounded by the intake-side timing pulley 27, the housing 56, and the inner cap 52 so as to be able to reciprocate in the axial direction of the intake-side camshaft 23.
A large number of teeth 59a, 5
9b is formed.

Correspondingly, a large number of teeth 52a, 5a are provided on the outer circumference of the inner cap 52 and the inner circumference of the housing 56.
6b are respectively formed. These teeth 59a, 5
9b, 52a, and 56b are helical teeth whose tooth traces intersect with the axis of the intake-side camshaft 23 at a predetermined angle. That is, the teeth 52a and the teeth 59b
Form a helical spline in which the teeth 56b and the teeth 59b are in mesh with each other. Then, by the engagement of these, the intake-side timing pulley 2
7, the housing 56 and the inner cap 52 are rotated.
Is transmitted to the intake side camshaft 23 through the Since the teeth 59a, 59b, 52a, and 56b are helical teeth, when the ring gear 59 moves in the axial direction of the intake-side camshaft 23, a twisting force is applied to the inner cap 52 and the housing 56, and the intake-side cam The shaft 23 moves relative to the intake-side timing pulley 27.

In the space S, a first hydraulic chamber 60 is formed at the front end of the ring gear 59 and a second hydraulic chamber 61 is formed at the rear end of the ring gear 59 in order to move the ring gear 59 in the axial direction. I have. The bearing cap 51 has a first hydraulic pressure supply hole 51a and a second hydraulic pressure supply hole 51b. Further, a first hydraulic pressure supply hole 51a and a first hydraulic chamber 6 are provided inside the intake side camshaft 23.
0 and a second hydraulic pressure supply passage 63 that connects the second hydraulic pressure supply hole 51b and the second hydraulic pressure chamber 61 are formed.

The lubricating oil sucked up from the oil pan 65 by the hydraulic pump 64 is supplied to each of the hydraulic pressure supply holes 51a and 51b through the oil filter 66 at a predetermined pressure. In addition, each hydraulic supply path 62, 6
In order to selectively supply the hydraulic pressure to each of the hydraulic chambers 60 and 61 through the respective hydraulic pressure supply holes 51a and 51b, an OCV8 is provided.
0 is connected.

The OCV 80 is a four-port directional control valve for switching a lubricating oil flow direction by causing a plunger 83 driven by an electromagnetic actuator 81 and a coil spring 82 to reciprocate a spool 84 in an axial direction. The duty of the electromagnetic actuator 81 is controlled, so that the opening is adjusted, and the magnitude of the hydraulic pressure supplied to the hydraulic chambers 60 and 61 is adjusted.

The casing 85 of the OCV 80 has a tank port 85t, an A port 85a, a B port 85b, and a reservoir port 85r. The tank port 85t is connected to the oil pan 65 via a hydraulic pump 64, and the A port 85a is connected to the first hydraulic supply hole 51.
a and the B port 85b are connected to the second hydraulic pressure supply holes 51b, respectively. The reservoir port 85r is connected to the oil pan 65.

The spool 84 is a cylindrical valve body.
It has four lands 84a for sealing the flow of the lubricating oil between the two ports, a passage 84b communicating between the two ports and allowing the flow of the lubricating oil, and two other passages 84c. .

In the VVT 50 having these configurations, OVT
When the drive of the CV 80 is controlled and the spool 84 is moved to the left in the drawing, the central passage 84b communicates the tank port 85t with the A port 85a, and lubricating oil is supplied to the first hydraulic supply hole 51a. . Then, the lubricating oil supplied to the first hydraulic pressure supply hole 51 a is supplied to the first hydraulic pressure chamber 60 via the first hydraulic pressure supply path 62, and the hydraulic pressure is applied to the distal end side of the ring gear 59. At the same time, the passage 84c on the right side in the figure is the B port 85b and the reservoir port 85r.
And the lubricating oil in the second hydraulic chamber 61 is supplied to the second hydraulic supply passage 63, the second hydraulic supply hole 51 b, and the B of the OCV 80.
The oil is discharged to the oil pan 65 via the port 85b and the reservoir port 85r.

Accordingly, the ring gear 59 is moved while rotating to the rear end side (rightward in the drawing) by the hydraulic pressure applied to the front end side, and twist is applied to the intake side camshaft 23 via the inner cap 52. . As a result, the rotation phase of the intake side camshaft 23 with respect to the intake side timing pulley 27 (crankshaft 14) is changed, and the intake side camshaft 23 rotates from the most retarded position to the most advanced position, and the intake valve 21 Is advanced.

The intake valve 21 whose valve opening timing is advanced in this way is opened while the exhaust valve 31 is opened, and the valve over which the intake valve 21 and the exhaust valve 31 are simultaneously opened. The lap period is extended. The movement of the ring gear 59 toward the rear end is regulated by the ring gear 59 abutting on the intake-side timing pulley 27. When the ring gear 59 abuts on the intake-side timing pulley 27 and stops, the intake valve 21 is stopped. The valve opening timing is the earliest.

On the other hand, when the drive of the OCV 80 is controlled and the spool 84 is moved rightward in the drawing, the central passage 84b communicates the tank port 85t with the B port 85b and lubricates the second hydraulic supply hole 51b. Oil is supplied. Then, the lubricating oil supplied to the second hydraulic pressure supply hole 51b is supplied to the second hydraulic pressure chamber 61 via the second hydraulic pressure supply path 63,
Oil pressure is applied to the rear end side of the ring gear 59.

At the same time, the passage 84c on the left side in FIG.
Communicates the A port 85a with the reservoir port 85r, and the lubricating oil in the first hydraulic chamber 60
2. The oil pan 6 via the first hydraulic pressure supply hole 51a, the A port 85a of the OCV 80, and the reservoir port 85r.
It is discharged to 5.

Accordingly, the ring gear 59 is moved while rotating to the front end side (left side in the drawing) by the hydraulic pressure applied to the rear end side, so that the intake camshaft 23 is twisted in the opposite direction via the inner cap 52. Granted. As a result,
Intake side timing pulley 27 (crankshaft 14)
, The rotational phase of the intake-side camshaft 23 is changed, the intake-side camshaft 23 rotates from the most advanced position to the most retarded position, and the valve opening timing of the intake valve 21 is retarded.

By delaying the valve opening timing of the intake valve 21 in this manner, the valve overlap period during which the intake valve 21 and the exhaust valve 31 are simultaneously opened is reduced or eliminated. The movement of the ring gear 59 toward the distal end is regulated by the contact of the ring gear 59 with the housing 56. When the ring gear 59 contacts the housing 56 and stops, the valve opening timing of the intake valve 21 becomes the latest. .

The valve timing of the intake valve 21 changed by the VVT 50 is determined based on the cam angle signal output from the cam angle sensor 44 and the crank angle signal output from the crank angle sensor 40 with respect to the crankshaft 14. The actual displacement angle of the intake camshaft 23 is calculated.

[0048] Next, will be described with reference to the control block diagram shown in FIG. 3 the control system of the valve timing control device VC for an internal combustion engine according to this embodiment. The ECU 70 includes a central processing unit (CPU) 71, a read-only memory (ROM) 72 in which a predetermined control program and the like are stored in advance, a CPU 71
Random access memory (R
AM) 73, a backup RAM 74 for storing data stored in advance, and the like, and a logical operation circuit in which these components are connected to an input interface 76, an output interface 77, and the like by a bidirectional bus 75.

The input interface 76 includes the throttle sensor 45, intake pressure sensor 46, engine speed sensor 41, cylinder discriminating sensor 42, water temperature sensor 43,
Oxygen sensors 47 are connected respectively. On the other hand, the injector 17, the igniter 19, and the OCV 80 are connected to the output interface 77, respectively.

The CPU 71 reads as input values signals from the fully closed switch 14a, the intake pressure sensor 46, the sensors 14, 30 to 34, the starter switch 39, and the like, which are input via the input interface 76. When reading this input value, the input interface 7
6, the throttle sensor 45, the intake pressure sensor 46,
Input values from the water temperature sensor 43 and the oxygen sensor 3 are subjected to analog / digital conversion processing. In the input interface 76, the engine speed sensor 4
1. Input values from the cylinder discrimination sensor 42, the vehicle speed sensor 34, and the like are subjected to waveform shaping processing. And
The CPU 71 includes an intake pressure sensor 46 and each of the sensors 30 to 34.
The injector 17 and the igniter 19 are suitably controlled based on the input values read from the.

The CPU 71 outputs the throttle opening degree TA, the engine speed NE, the intake pressure PW and the like among the signals read as input values from the intake pressure sensor 46, the sensors 40 to 47, etc. via the input interface 76. OCV as a data signal through the interface 77
Output to 80.

Next, the operation of the valve timing control device VC for the internal combustion engine configured as described above will be described.
4 (a) is a flow chart of the "main routine" executed by the ECU 70, is executed as an interrupt at predetermined time intervals for each 8 ms.

First, in this routine, in step 101, the throttle opening TA, the engine speed NE, and the intake pressure PW, which are detected by the throttle sensor 45, the engine speed sensor 41, and the intake pressure sensor 46, are read. The throttle opening change amount ΔTA by subtracting the throttle opening TA _i-1 read at the previous routine from the throttle opening degree TA _i read in this routine at the next step 102. And step 1
At 03, it is determined whether or not the throttle opening difference ΔTA is smaller than a preset deceleration determination value X (X is a value of “0” or “minus”). If the throttle opening difference ΔTA is smaller than the deceleration determination value X, it is determined that the vehicle is decelerating, and the process proceeds to step 104. In step 104, the deceleration determination count ΔTAC is not incremented. On the other hand, the throttle opening change amount ΔTA
If is not smaller than the deceleration determination value X, it is determined that the vehicle is not decelerating, and the routine proceeds to step 105, where the count value of the deceleration determination count value ΔTAC is incremented.

[0054] Referring now to FIG. 4 the operation of the "VVT control routine"
This will be described with reference to the flowchart of FIG. Step 1
In step 06, the target displacement angle VTTB is calculated from the map shown in FIG. 9 based on the engine speed NE and the intake pressure PM read in the main routine. In step 107, the deceleration determination count value ΔTAC counted in the main routine is compared with a predetermined time Y for executing the advance angle restriction after the deceleration determination. here,
If the deceleration determination count value ΔTAC is smaller than the predetermined time Y, the process proceeds to step 108. In step 108, the previous control target displacement angle VTT _i-1 used when the OCV 80 was driven and controlled in the previous routine, and the target displacement angle VTTB calculated in step 106.
Compare with Here, the previous control target displacement angle VTT
_{If i-1} is smaller than the target displacement angle VTTB, the process proceeds to step 109. In step 109, the control target displacement angle VTT _i used when the OCV 80 is driven and controlled in this routine is set to the previous control target displacement angle VTT _i-1 used in the previous routine.

On the other hand, if the deceleration determination count value ΔTAC is not smaller than the predetermined time Y in step 107, the process proceeds to step 110. If the previous target displacement angle VTT _i-1 is not smaller than the target displacement angle VTTB in step 108, the process proceeds to step 110. The control target displacement angle VTT _i used in the routine at step 110, sets the target displacement angle VTTB calculated in step 106,
Move to step 111.

In step 111, the drive duty DVT of the OCV 80 is calculated by the following equation. DVT = (VTT _i -VT) * KP + GDVTH VTT _i : target displacement angle for current control VT: actual displacement angle of cam angle with respect to crank angle KP: proportional gain GDVTH: holding duty Controls the drive of the OCV 80 with the calculated drive duty DVT, and terminates the subsequent processing once.

As described above, the valve timing is changed.
The valve timing control for changing the valve timing is executed. This
As described above, in the present embodiment, during deceleration, the previous valve
Previous control target displacement angle V used during timing control
TT_i-1Than the map based on this driving condition
If the calculated target displacement angle VTTB is large,
Control target displacement angle VTT_i-1Is the control eye used this time
Target displacement angle VTT_iIs set as On the other hand,
Previous control target displacement angle used during the timing control
VTT _i-1Rather than the target change calculated in this routine.
When the position angle VTTB is small, the target displacement angle VTTB is
Control target displacement angle VTT used this time_iSet as
It is. In other words, when decelerating, the eye with the smaller advance update amount
Target displacement angle VTTB or VTT_i-1Is selected and set as appropriate
You. Then, the target displacement angle VTTB on the selected side or
Is VTT_i-1Based on the predetermined time (Y seconds
During this period, the advance update amount is limited and the VVT 50 is driven.
Dynamic control.

[0058] As a result, it changes the state of the control target displacement angle VTT and the target displacement angle VTTB in when it is decelerated from the high load region in a low load region as shown in FIG. 5 (c). Target displacement angle VTTB when decelerating from a high load range to a low load range
As shown by the solid line in the figure, as described in the above-mentioned prior art, after once reaching the most advanced position near the middle load range, it changes to the retard side.

On the other hand, in the present embodiment, as shown by the dotted line in the figure, the change state of the control target displacement angle VTT is a predetermined time after the previous control target displacement angle VTT _i-1 is continued from the start of deceleration. Used until (Y seconds) elapse. That is, in the present embodiment, the predetermined value of the increase amount of the valve overlap amount is set to “0” during deceleration. After the elapse of Y seconds, the control target displacement angle VTT is set to the target displacement angle VTTB.
As a result, an over-advance of the actual displacement angle VT (shown by a dashed line in the figure) at the time of deceleration is prevented, and misfiring or poor combustion in a low load region due to the over-advance of the valve timing, and drivability Can be prevented from deteriorating.

Further, in this embodiment, unlike the prior art in which the limit advance value is fixed, the control target displacement angle VTT is set to the control target displacement angle VTT _i-1 used last time. As a result, even if the actual displacement angle VT before deceleration is near the maximum advance side (for example, 30 ° CA), the shock and the actual displacement angle VT generated by forcibly changing the valve timing to the retard side are reduced. It is possible to prevent a shock caused by a large change, and to further improve drivability.

Further, in the present embodiment, the target displacement angle VTTB calculated from the map is used as the control target displacement angle VTT during deceleration in the low load range and during acceleration from the low load range, so that emission and fuel efficiency are good. Can be held.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In this embodiment, since the mechanical and electrical configuration is the same as that of the first embodiment, the same reference numerals are given and the description thereof will be omitted, and in particular, the difference from the first embodiment will be described. This will be mainly described.

In this embodiment, the contents of control by the ECU 70 are different from those in the first embodiment. Next, a VVT control program in the valve timing control device VC of the internal combustion engine according to the present embodiment will be described. 6 (a) is a flowchart showing the "main routine" executed by the ECU 70. First, in step 201, the throttle opening T based on the detection of the throttle sensor 45, the engine speed sensor 41, the intake pressure sensor 46, and the like.
A, the engine speed NE, the intake pressure PW, etc. are read. Next in step 202 by subtracting the intake air pressure PM _i-1 read at the previous routine from the intake pressure PM _i read in the current routine intake pressure change amount ΔP
Find M.

[0064] Next, the action of "VVT control routine" 6
This will be described with reference to the flowchart of FIG. Step 2
In step 03, the target displacement angle VTTB is calculated from the map shown in FIG. 9 based on the engine speed NE and the intake pressure PM read in the main routine. In step 204, the previous control target displacement angle VTT _i-1 and the target displacement angle V
If the previous control target displacement angle VTT _i-1 is smaller than the target displacement angle VTTB, the process proceeds to step 205. In step 205, the target displacement angle update amount Δ
Calculate VTT. The calculation of the target displacement angle update amount ΔVTT is made with reference to the map shown in FIG 8 which is stored in advance in ROM 72. This map shows the intake pressure change amount ΔPM
, The target displacement angle update amount ΔVTT is set.
The target displacement angle update amount ΔVTT is set to decrease as the intake pressure change amount ΔPM increases, that is, as the degree of deceleration increases.

In step 206, the previous control target displacement angle VT is calculated from the target displacement angle update amount ΔVTT and the target displacement angle VTTB calculated in step 203.
The value obtained by subtracting T _{i- 1} is compared with the actual displacement angle update amount.
If the target displacement angle update amount ΔVTT is less than the actual displacement angle update amount, the process proceeds to step 207. Step 20
In step 7, the value obtained by adding the target displacement angle update amount ΔVTT calculated in step 205 to the previous control target displacement angle VTT _i−1 is used as the control target displacement angle VTT used in the current routine.
TT _i is set, and the routine goes to Step 208.

On the other hand, if the previous control target displacement angle VTT _i-1 is not smaller than the target displacement angle VTTB in step 204, the process proceeds to step 209. Also,
In step 206, the target displacement angle update amount ΔVTT
If is not smaller than the actual displacement angle update amount, step 2
Move to 09. In step 209, the target displacement angle VTTB is used as the control target displacement angle V used in the current routine.
TT _i is set, and the routine goes to Step 208. In steps 208 and 210, the drive duty DVT of the OCV 80 is calculated, and the OCV8 is calculated based on the drive duty DVT.
0, and the subsequent processing is once ended.

As described above, the valve timing control for changing the valve timing is executed. As described above, in the present embodiment, at the time of deceleration, the previous target displacement angle VTT used during the previous valve timing control is used.
_{If the} target displacement angle VTTB calculated from the map based on the operating state is larger than _i-1 , the target displacement angle VTT _i-1 is set to the target displacement angle .DELTA.PM (degree of deceleration) of the intake pressure PM at that time. The displacement angle obtained by adding the displacement angle update amount ΔVTT is set as the control target displacement angle VTT _i used this time.

As a result, the same effect as in the first embodiment can be obtained.
Obtainable. Further, in the present embodiment, during deceleration,
The predetermined value of the increase of the lube overlap amount is determined by the degree of deceleration.
Is set smaller as7
As shown in (e) and (f), from a high load range to a low load range,
Or, when decelerating from a high load area to a medium load area,
The target displacement angle VTT gradually
Can be approached. As a result, overspeed during deceleration
-Controlling the overlap amount to the valve overlap amount
It is possible to prevent shocks during normal control without limiting
it can.

The present invention can also be configured as follows. (1) In each of the above embodiments, the VVT 50 driven by using a hydraulic pressure as a drive source for continuously changing the opening / closing timing of the intake valve 21 is used. However, the VVT driven by an actuator such as a step motor as a drive source is used. May be used.

(2) In the above embodiment, the target displacement angle VTT
Although the detected value of the intake pressure PM is used to calculate B, the target displacement angle VTTB may be calculated by using the detected value of the intake air amount instead of the intake pressure PM.

(3) In each of the above embodiments, the intake valve 2 is controlled by the VVT 50 provided on the camshaft 23 on the intake side.
Only the opening / closing timing of No. 1 was changed to adjust the valve overlap. On the other hand, a VVT may be provided on the exhaust-side camshaft 33, and only the opening / closing timing of the exhaust valve 31 may be changed by the VVT to adjust the valve overlap. Alternatively, VVTs may be provided on both the intake and exhaust camshafts 23, 33, and the valve overlap may be adjusted by changing the opening / closing timing of the intake valve 21 and the exhaust valve 31 with each VVT. Good.

(4) In each of the above embodiments, the present invention is embodied by a valve timing control device of a gasoline engine, but may be embodied by a valve timing control device of a diesel engine.

[0073]

As described above, according to the valve timing control apparatus for an internal combustion engine according to the first aspect, when the valve timing is changed at the time of deceleration, the amount of increase in the valve overlap amount is equal to or less than a predetermined value. In this way, the target displacement angle is changed. As a result, it is possible to prevent the Re retardation operation of the variable valve timing mechanism, able to prevent the shock at the time of changing the valve timing. Further, even if the actual displacement angle before deceleration is near the maximum displacement angle, the valve timing is not forcibly changed to the retard side, so that a shock at the time of changing the valve timing can be prevented. As a result, there is an excellent effect that drivability, fuel efficiency and the like can be favorably maintained.

According to the valve timing control device for an internal combustion engine according to the second aspect, in addition to the effect of the first aspect, the larger the deceleration of the internal combustion engine, the larger the amount of increase in the valve overlap amount. Since the target displacement angle is changed so as to decrease the valve timing, the valve timing can be gradually approached to the target displacement angle, and further, an excellent effect that a shock at the time of changing the valve timing can be prevented can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine system and the like in a first embodiment.

FIG. 2 is a schematic configuration diagram of a variable valve timing mechanism system according to the first embodiment.

FIG. 3 is a block diagram illustrating an electrical configuration of an ECU and the like according to the first embodiment.

FIG. 4A is a flowchart showing a “main routine” executed by the ECU, and FIG. 4B is a flowchart showing a “VVT control routine” executed by the ECU.

FIG. 5A is a graph showing a change in a throttle opening.
(B) is a graph showing a change in intake pressure. (C) is a graph showing changes in the target displacement angle, the control target displacement angle, and the actual displacement angle when decelerating from a high load range to a low load range.

FIG. 6A is a flowchart illustrating a “main routine” executed by the ECU according to the second embodiment, and FIG. 6B is a flowchart illustrating a “VVT control routine” executed by the ECU.

FIG. 7A is a graph showing a change in throttle opening.
(B) is a graph showing a change in intake pressure. (C) is a graph showing a change in an intake pressure change amount. (D) is a graph showing a change in a control target displacement angle change amount. (E) is a graph showing changes in the target displacement angle, the control target displacement angle, and the actual displacement angle when decelerating from a high load region to a low load region. (F) is a graph showing changes in the target displacement angle, the control target displacement angle, and the actual displacement angle when decelerating from a high load region to a medium load region.

FIG. 8 is a map showing a relationship between a control target displacement update amount and an intake pressure change amount.

FIG. 9 is a map showing a relationship between a target displacement angle with respect to an engine speed and an intake pressure.

FIG. 10A is a graph showing a change in throttle opening. (B) is a graph showing a change in intake pressure. (C) is a graph showing the change in the target displacement angle and the actual displacement angle when decelerating from a high load range to a low load range in the conventional art. (D) is a graph showing changes in the target displacement angle and the actual displacement angle when decelerating from a high load range to a low load range in which the actual displacement angle is controlled by adding a limit value to the advance angle value. (E) is a graph showing changes in the target displacement angle and the actual displacement angle when the actual displacement angle before deceleration is on the advance side of the limit advance value.

[Explanation of symbols]

10 engine as internal combustion engine, 15 combustion chamber, 20
... intake passage, 21 ... intake valve, 22 ... intake port, 2
6 ... Throttle valve, 30 ... Exhaust passage, 31 ... Exhaust valve, 40 ... Crank angle sensor, 41 ... Engine speed sensor, 44 ... Cam angle sensor, 45 ... Throttle sensor, 46 ... Intake pressure sensor, Each of the sensors constitutes operating state detecting means, and the cam angle sensor 4
Reference numeral 7 and the like constitute valve timing detection means. ),
50: variable valve timing mechanism; 70: ECU constituting target displacement angle calculation means, drive control means, target displacement angle change means, setting means, VC: valve timing control device for internal combustion engine.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-3-189336 (JP, A) JP-A-6-173723 (JP, A) JP-A 8-49576 (JP, A) JP-A-7- 301106 (JP, A) Japanese Utility Model Hei 5-66237 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 13/02 F01L 1/34 F02D 45/00

Claims (2)

(57) [Claims] 1. An intake valve and an exhaust valve which are driven at a predetermined timing in synchronization with the rotation of an internal combustion engine mounted on a vehicle to open and close an intake passage and an exhaust passage leading to a combustion chamber, respectively, A variable valve timing mechanism driven to continuously change at least one of the opening and closing timings of the exhaust valve, and a valve timing for detecting an actual displacement angle of the valve on a side where the variable valve timing mechanism is disposed. Detecting means; operating state detecting means for detecting an operating state of the internal combustion engine; and a valve when the operating state detecting means detects that the state of the internal combustion engine is in a high load range or a low load range. If it is detected that the amount of overlap is small, or if the state of the internal combustion engine is detected to be in the middle load range, the valve overlap Target displacement angle calculating means for calculating a target displacement angle so that the amount of displacement becomes large; an actual displacement angle detected by the valve timing detecting means; and a target displacement angle calculated by the target displacement angle calculating means. based, a drive control means for driving and controlling the variable valve timing mechanism so as to change the valve overlap amount, the increase amount when said valve overlap amount during deceleration of the internal combustion engine is increased and the predetermined value or less It said drive control means a valve timing control apparatus of combustion engine Ru and a target displacement angle changing means for changing the target displacement angle referenced so. 2. The valve timing control of an internal combustion engine according to claim 1, wherein the target displacement angle changing means has a setting means for setting the predetermined value to be smaller as the degree of deceleration of the internal combustion engine is larger. apparatus.