JP3129802B2 - Valve timing control system 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 system for an internal combustion engine for controlling the valve timing of an internal combustion engine.
On-time.

[0002]

2. Description of the Related Art A valve timing control apparatus for changing the valve timing of an internal combustion engine according to the operating state of the internal combustion engine has been known (for example, Japanese Patent Laid-Open No. 59-11 / 1984).
No. 9007). That is, this device delays the closing timing of the intake valve when the internal combustion engine is under a low load, reduces pumping loss of intake air, and improves fuel efficiency.

[0003]

Generally, in a vehicle brake system, a negative pressure in an intake pipe is introduced into a brake booster (negative pressure tank), and the negative pressure is used to double a driver's brake depressing force. . Further, there is a device for introducing a fuel evaporative gas into an intake pipe in order to prevent a fuel evaporative gas (evaporative gas) generated from a fuel tank from being released into the atmosphere. Also in this case, the fuel evaporative gas is introduced using the negative pressure in the intake pipe.

In the above-described valve timing control device, if the closing timing of the intake valve is delayed, the negative pressure in the intake pipe becomes small. When the negative pressure in the intake pipe is reduced as described above, a large depressing force is required when the brake is used, and the feeling of use of the brake is deteriorated, or the fuel evaporative gas is not sufficiently introduced into the intake pipe. Such a problem occurs.

Accordingly, the present invention has been made to solve the above problems, and in a device for controlling a valve timing of an internal combustion engine, a device utilizing a negative pressure in an intake pipe always operates normally. It is an object of the present invention to provide a device capable of performing such operations.

[0006]

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
Valve timing control system for an internal combustion engine according to the present invention
Arm, in order to control the closing timing of the intake valve of an internal combustion engine, the valve timing control device for controlling the valve timing, calculates a closing timing of the intake valve in accordance with the operating condition of the internal combustion engine, the result of the calculation First valve timing calculation means for outputting a control signal to the valve timing control device based on the pressure, a negative pressure tank for introducing a negative pressure in an intake pipe of the internal combustion engine and storing the negative pressure, A negative pressure detecting means for detecting a negative pressure stored in the tank; and, based on a detection result of the negative pressure detecting means in the tank, determining that the negative pressure in the tank is more positive than a predetermined pressure. Second valve timing calculating means for outputting a control signal to the valve timing control device in order to advance the closing timing of the valve .
The second valve timing calculating means closes the intake valve.
The valve timing control device for advancing timing
Output the control signal to the first valve tie.
Priority is given to the output of the
Closing the intake valve using the output of the
Adopt the technical means that controls the timing.

[0008]

[0009]

According to the present invention, it detects the pressure of the negative pressure in the tank for storing the negative pressure in the intake pipe, on the basis of the detection result, the negative pressure of the negative pressure in the tank in the second valve timing computing means predetermined When it is determined that the pressure is on the positive pressure side from the pressure, the closing timing of the intake valve of the internal combustion engine may be advanced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 2 is a diagram showing the overall configuration of an internal combustion engine provided with the valve timing control device of the present embodiment.

In FIG. 2, an air cleaner 1 for purifying air and an intake pipe 2 are continuous, and the intake air taken in through the air cleaner 1 passes through the intake pipe 2 and passes through the combustion chamber 16.
Supplied to A throttle valve 8 is provided in the intake pipe 2. The throttle valve 8 opens and closes in conjunction with an accelerator pedal 6, and controls the intake amount of the intake air. Further, an intake valve 10 that opens and closes between the intake pipe 2 and the combustion chamber 16 by the rotational force of the camshaft 3.
Are arranged. Here, the camshaft 3 is provided with a variable valve timing device 4 described later, and the variable valve timing device 4 changes the opening / closing timing of the intake valve 10 based on a control signal from the electronic control device 50. The camshaft is provided with a camshaft position sensor 9 for detecting a camshaft position, and a signal from the camshaft position sensor 9 is input to an electronic control unit 50 described later.

A communication pipe 13 which is continuous with the intake pipe 2 is provided at a part of the intake pipe 2. One end of the communication pipe 13 is connected to the negative pressure tank 11, and a check valve 13 is provided on a part of the communication pipe 13. This allows
The negative pressure in the intake pipe 2 passes through the communication pipe 13 and passes through the negative pressure tank 11.
Introduced within. An operation of doubling a braking force in a brake device (not shown) and an operation of guiding a fuel evaporative gas described later into the intake pipe 2 are executed using the negative pressure in the negative pressure tank 11. Further, the negative pressure tank 11
Is provided with a pressure sensor 12 as a negative pressure detecting means for detecting a pressure in the negative pressure tank 11 and outputting a linear signal according to the pressure, and a signal from the pressure sensor 12 is also provided by an electronic control unit described later. 50 is input.

The combustion chamber 16 is connected to an exhaust pipe 20, and combustion gas generated in the combustion chamber 16 during an explosion stroke of the internal combustion engine is discharged from the combustion chamber 16 through the exhaust pipe 20. An exhaust valve 18 is provided between the combustion chamber 16 and the exhaust pipe 20, and the exhaust valve 18 is also opened and closed by the rotational force of the camshaft 6, similarly to the intake valve 10.

A crank angle sensor 7 for detecting a rotation speed of the internal combustion engine is provided on a crank shaft of the internal combustion engine. A signal from the crank angle sensor 7 is also input to an electronic control unit 50 described later. You.

On the other hand, the liquid fuel stored in the fuel tank 22 is pumped up by a fuel pump 24 and sent to an injector 26 provided in the intake pipe 2 under pressure. Then, the injector 26 supplies the fuel to the combustion chamber 16 at an optimum fuel injection amount and injection timing based on a control signal from an electronic control device 50 described later.

A communication pipe 28 is connected to the fuel tank 22, and the communication pipe 28 connects the fuel tank 22 and the canister 30 to each other. Then, the fuel gas generated from the fuel in the fuel tank 22 is introduced into the canister 30 through the communication pipe 28. Here, an adsorbent 34 is provided in the canister 30, and activated carbon is stored in the adsorbent 34. Thereby, the adsorbent 34
Can adsorb the fuel gas.

On the other hand, an open-to-atmosphere hole 36 is provided at one end of the canister 30 so that outside air can be sucked into the canister 30 through the open-to-atmosphere hole 36. Further, a supply pipe 38 is connected to the canister 30, and the other end of the supply pipe 38 is connected to a purge control valve 40. The purge control valve 40 is provided with a supply pipe 42, and the other end of the supply pipe 42 is connected to the negative pressure tank 11. Thereby, the canister 30 and the intake pipe 2 are connected to the supply pipe 38,
Purge control valve 40, supply pipe 42, and negative pressure tank 11
Is communicated through. The purge control valve 40 opens and closes in response to a control signal from an electronic control unit 50 to be described later, and connects or disconnects the canister 30 and the intake pipe 2. That is, when the purge control valve 40 is opened, the atmosphere is introduced from the atmosphere opening hole 36 due to the negative pressure in the intake pipe 2 and the negative pressure tank 11, and is guided to the intake pipe 2 together with the fuel gas adsorbed by the canister 30. Thus, the fuel gas is burned in the combustion chamber 16.

An electronic control unit (hereinafter referred to as an ECU) 50
Is a control signal for calculating the optimal control amounts of the fuel system and the ignition system based on the detection signals from the sensors (not shown), and for appropriately controlling the injector 26, the purge control valve 40, and the ignition device (not shown). Is a control device that outputs

The ECU 50 includes an arithmetic unit (CPU) 52 for performing arithmetic processing, a read-only ROM 5 for storing a control program and control constants required for the arithmetic operation.
4, a RAM 56 for temporarily storing operation data during the operation of the CPU 52, and an input / output circuit 58 for inputting and outputting signals from outside the ECU 50.

Further, the ECU 50 controls the intake valve 1 based on information from a throttle opening sensor (not shown), a crank angle sensor 7, a camshaft position sensor 9, and the like.
The first valve timing calculating means calculates the closing timing of 0, and the second valve timing calculating means calculates the advance amount of the closing timing of the intake valve 10 based on information from the pressure sensor 12 and the like.

Next, the variable valve timing device 4 shown in FIG. 2 will be described with reference to FIG. In FIG. 3, the shaft 61 is fixed to the camshaft 3 by bolts 62. An external tooth helical spline portion 63 is formed on the shaft 61, and a helical tooth is provided on the outer periphery of the external tooth helical spline portion 63.

On the other hand, the cam pulley 65 is slidably fitted to the camshaft 3 via the shaft 61 and the intermediate shaft 64 in the camshaft rotation direction. An internal tooth helical spline portion 66 is formed inside the cam pulley 65, and a helical tooth is provided on the inner periphery of the internal tooth helical spline portion 66.

The intermediate shaft 64 is provided with an internal spline portion 64a and an external spline portion 64b. The internal spline portion 64a meshes with the external helical spline portion 63 of the shaft 61 and the external spline portion 6
4b is the internal helical spline portion 66 of the cam pulley 65
Are engaged. Thus, the intermediate shaft 64 can slide in the cam shaft direction. Further, the intermediate shaft 64
Is provided with a small-diameter cylindrical bearing contact portion 64c,
A piston 68 is provided coaxially on the outer periphery of the bearing contact portion 64c via a ball bearing 67. The piston 68 is non-rotatable with respect to the inner peripheral wall 69 a of the housing 69, and is slidable oil-tightly in the cam shaft direction via a piston ring 79.

On the other hand, a leg 69b is formed in the housing 69, and the leg 69b and a fixing portion 70 provided on a cylinder head of the internal combustion engine are fixed by bolts 71. The housing 69 supports the intermediate shaft 64 via a bearing 72. A return spring 74 is provided between the intermediate shaft 64 and the shaft 61. The return spring 74 pushes the intermediate shaft 64 leftward in FIG. 3 and also pushes the piston 68 leftward.

On the other hand, a hydraulic chamber 73 is formed between the housing 69 and the piston 68, and hydraulic oil pumped by an oil pump 81 from an oil pan 80 of the internal combustion engine is guided into the hydraulic chamber 73. An electromagnetic valve 82 is provided between the oil pump 81 and the hydraulic chamber 73, and the electromagnetic valve 82 controls hydraulic oil guided to the hydraulic chamber 73. Then, the hydraulic oil introduced into the hydraulic chamber 73 is returned to the oil pan 80 by the electromagnetic valve 83 again. The opening and closing of the solenoid valve 82 and the solenoid valve 83 are controlled by a control signal from the ECU 50 described above.

Next, the operation of the variable valve timing device 4 in the above-described device will be described. The variable valve timing device 4 is controlled by a hydraulic pressure guided to a hydraulic chamber 73. That is, as described above, the solenoid valve 8
When the valve 2 is opened, hydraulic oil is guided from the oil pump 81 to the hydraulic chamber 73. As a result, the pressure in the hydraulic chamber 73 increases, and the pressure acting on the hydraulic chamber 73 is reduced by the return spring 7.
When the pressing force of 4 is exceeded, the piston 68 moves rightward in FIG. When the hydraulic pressure acting on the piston 68 becomes larger than the sum of the thrust load of the external teeth and the internal teeth received by the intermediate shaft 64 and the pressing force of the return spring 74, the intermediate shaft 64 also moves rightward in FIG. As described above, the intermediate shaft 64 slides between the internal tooth helical spline portion 64a and the external tooth helical spline portion 64b.
5, the camshaft 3 is advanced relatively. That is, the closing timing of the intake valve 10 can be advanced.

Thereafter, when the solenoid valve 83 is opened, the hydraulic chamber 7 is opened.
3, the intermediate shaft 64 moves to the left with respect to the cam pulley 65 and the shaft 3 in FIG. Thereby, the camshaft 3 is retarded relatively to the cam pulley 65. That is, the closing timing of the intake valve 10 can be delayed.

Therefore, by controlling the hydraulic oil (pressure in the hydraulic chamber 73) guided to the hydraulic chamber 73, the rotation phase of the cam shaft 3 and the cam pulley 65 is shifted, and the valve timing is changed.

Hereinafter, the operation of the variable valve timing device 4 which is a main part of the present embodiment will be described in more detail with reference to the flowcharts shown in FIGS. In addition,
The routines of FIGS. 4 and 5 are interrupted at predetermined time intervals.

In step 100, information on detection signals from the ECU 50, such as the crank angle sensor 7, the camshaft position detection sensor 9, and an unillustrated engine load sensor (for example, a throttle opening sensor) is read. Step 11
At 0, a relative angle difference θ between the crank angle θ ₁ and the cam shaft position θ ₂ is calculated based on the detection results of the crank angle sensor 7 and the cam shaft position detection sensor 9. Note that FIG. 6 shows this angle difference θ, which is calculated in detail based on Equation 1.

[0031]

From the read information in Equation 1] θ = θ ₂ -θ ₁ step 120 At step 100, the target advance angle difference theta in the current internal combustion engine state
to set _a. Specifically, for example, it is set from a two-dimensional map determined from the throttle opening and the engine speed as shown in FIG.

In step 130, the detection of the pressure sensor 12 is performed.
Based on the signal, the pressure P in the negative pressure tank 11_T(Negative pressure)
Read. In step 140, the pressure in the negative pressure tank 11 is
Force P _TIs greater than the predetermined negative pressure P2, or the value of the counter
Whether C satisfies one of the conditions of not 0
Is determined. And if this condition is satisfied,
Proceed to step 150, if not, step 16
Go to 0. Here, it is assumed that the counter value C is not 0.
Is a valve set to be described later to secure a negative pressure in the intake pipe 2.
This means that the control process of the imaging is being executed. Ma
The pressure P_TIs a negative pressure, the pressure P_TIs the predetermined negative pressure P
Greater than 2 means pressure P_TIs on the negative pressure side from the predetermined negative pressure P1
Means that

The pressure P _T in the negative pressure tank 11 in step 150 it is determined whether to satisfy either of the conditions in the range of greater than a predetermined negative pressure P1, or the value C of the counter is 0. Here, if this condition is satisfied, the process proceeds to step 210;
Go to 0. In other words, by executing the determination processing of steps 140 and 150, the negative pressure tank 1 as shown in FIG.
When the pressure _PT in the pump 1 becomes smaller than the predetermined negative pressure P2, a process (to be described later) for increasing the negative pressure in the intake pipe 2 is executed, and thereafter, the above process is executed to reduce the pressure _PT to a predetermined value. When the pressure becomes larger than the negative pressure P1, this processing is terminated.

Steps 160 to 200 show a process for increasing the negative pressure in the intake pipe 2.
In target advancing angle difference theta _a to determine whether or not the maximum advance angle theta _Z smaller. Then, the target advance angle difference theta _a proceeds to step 170 if the maximum advance angle theta _Z smaller, the process proceeds to step 190 if not smaller. Note that the maximum advance angle θ _Z is a value at which the closing timing of the intake valve 10 cannot be advanced any more due to its structure, and is a value that is set in advance for each internal combustion engine.

The incremented counter value C in step 170 (C ← C + 1) , calculates a correction value Z for correcting the step 180 the target advance angle difference theta _a (Z
← Z + alpha) together, by correcting the target advance angle difference theta _a by adding the correction value Z to the target advance angle difference theta _a step 2
Go to 00. As a result, the target advance angle difference θ _a becomes the correction value Z
Only the advance side is controlled. On the other hand, by limiting the step 190 the target advance angle difference theta _a to the maximum advance angle theta _Z Step 2
Go to 00. In step 200, an XBT flag indicating that the above-described process for increasing the negative pressure in the intake pipe 2 is being executed is set (XBT ← 1), and step 3 is performed.
Go to 00.

[0036] to determine whether the actual angular difference obtained in step 110 In step 300 theta is equal to the target advance angle difference theta _a, the process proceeds to step 320 if match, the solenoid valve in step 320 82 and 83 are closed,
Proceed to step 350. Thereby, the piston 68 is held at a predetermined position, and the valve timing is also held at an optimum value. On the other hand, when the angle difference theta is determined not to match the target advance angle difference theta _a in step 300 proceeds to step 310, determine the angular difference at step 310 theta is whether smaller target advance angle difference theta _a If it is smaller, the process proceeds to step 340, and if not, the process proceeds to step 330.

At step 340, the solenoid valve 82 is opened and the solenoid valve 83 is closed, and the routine proceeds to step 350.
Accordingly, the hydraulic pressure guided to the hydraulic chamber 73 increases as described above, and the piston 68 moves rightward in FIG. 3 to increase the angle difference θ. At step 330, the solenoid valve 82 is closed, and the solenoid valve 83 is opened.
Proceed to. As a result, the hydraulic pressure in the hydraulic chamber 73 decreases, and the piston 68 moves to the left in FIG. 3 to reduce the angle difference θ. Step target advancing angle difference in set in the current execution timing 350 theta _a previous target advance angle difference theta
This routine ends as _a-1 . That is, by executing the processing of steps 300 to 340, the angle difference θ
There is feedback controlled so that the target advancing angle difference theta _a, always angular difference theta is controlled to an optimum value in accordance with the operating state of the internal combustion engine.

At the next execution timing, step 140
In step 15, since the value C of the counter is not 0,
Proceeds to 0, the pressure P _T is a predetermined negative pressure P in the pressure P _T is determined whether or not larger than the predetermined negative pressure P1 in step 150
The process of increasing the negative pressure in the intake pipe 2 (steps 160 to 190) is repeatedly executed until the pressure becomes larger than 1.

[0039] Here, More particularly the process of securing a negative pressure in the intake pipe 2, in which by increasing the step 180 the correction value Z by the predetermined value alpha, gradually increasing the target advance angle theta _a is there. As a result, the closing timing of the intake valve 10 is gradually controlled to the advanced side, and the advance of the closing timing of the intake valve 10 prevents the backflow of the intake air from the intake valve 10 so that the intake pipe 2 is closed. The negative pressure increases.

[0040] Then, the pressure P _T is greater than a predetermined negative pressure P1, the process proceeds to step 210 is affirmative determination is made in step 150. In step 210, it is determined whether or not the XBT flag is set. If the XBT flag is set, the process proceeds to step 220, and if not, the process proceeds to step 260.

The target advancing angle difference theta obtained in the target currently obtained in step 220 advance angle difference theta _a and the previous execution timing
the absolute value of the difference between the _a-1 it is determined whether or not larger than a predetermined value theta _b, the process proceeds to if step 260 large, the process proceeds to step 230 if not greater.

[0042] Step 230 to 250 in order to increase the negative pressure in the intake pipe 2, the target advance adapted to the operating state is gradually retarded target advance angle difference theta _a set to the advance side as described above shows a process for approximating the angle difference theta _a, first calculates the correction value Y for correcting the step 230 the target advance angle difference theta _a. Here, the initial value of the correction value Y is the final value of the correction value Z obtained in step 180. In this embodiment, by setting the predetermined value β to a value larger than the above-mentioned predetermined value α, it is possible to perform control so as to quickly converge to a value corresponding to the state of the internal combustion engine (the value obtained in step 120). However, the value β is not particularly limited to this, and the value β may be set to a value equal to the value α.

In step 240, it is determined whether or not the correction value Y is larger than 0.
In step 250, the target advance angle difference θ _a is calculated using the correction value Y.
Is corrected, the routine proceeds to step 300, where the above-described processing is executed, and this routine is terminated. Then, until it is determined in step 240 that the correction value Y is not larger than 0,
Target advancing angle difference theta _a other words repeatedly corrects the target advance angle difference theta _a to a value before being controlled to the advance side in step 180. Thereafter, if it is determined that the correction value Y is not larger than 0, an affirmative determination is made in step 240 and the process proceeds to step 260.

Here, the conditions for executing the process of step 260 will be described in more detail. First, when the pressure _PT is higher than the predetermined negative pressure P2 and the processing for increasing the negative pressure in the intake pipe 2 in steps 160 to 190 is not performed, the processing in steps 230 to 250 needs to be performed. There is no. Therefore, it is determined in step 210 that the XBT flag has not been set, and step 260
Proceed to. Second, when the absolute value of the deviation from the target advance angle difference θ _a-1 obtained at the previous execution timing is larger than the predetermined value θ _b, it is a case where the driver intentionally changes the driving state. Therefore, at this time, the target advance angle difference θ is gradually increased as described above.
There is no need to change _a . Therefore, the determination at step 220 is affirmative and the routine proceeds to step 260. Third, the processing of steps 160 to 190 is executed to obtain the target advance angle difference θ.
_{If a} is retarded by the amount controlled to the advance side, step 24
If the answer is 0, the process proceeds to step 260.

In step 260, the counter value C is reset (C ← 0) and the XBT flag is reset (XBT ← 0). Without correcting the step 270 the target advance angle difference theta _a with it set to the value determined in step 120, it resets the correction value Z and the correction value Y (Z ← 0, Y ← 0) to proceed to step 300 After executing the above-described processing, this routine ends.

Therefore, as described above, the pressure sensor 1
Based on the detection signal from the 2, when the intake pipe negative pressure is smaller than a predetermined negative pressure, finally the actual angular difference theta increases in order to target advance angle difference theta _a is set to a large value, thus The closing timing of the intake valve 10 can be advanced, and the negative pressure in the intake pipe can be increased. Therefore, there is no inconvenience that the feeling of use of the brake is deteriorated due to a decrease in the negative pressure in the intake pipe or that the fuel evaporative gas is not sufficiently introduced into the intake pipe.

Further, since the pressure _PT in the negative pressure tank 11 is detected, and when the pressure becomes lower than the predetermined negative pressure P2, the above-described processing is executed to increase the negative pressure in the intake pipe 2. The inside of the negative pressure tank 11 can always be maintained at a predetermined negative pressure or higher. Therefore, for example, when the vehicle is running on a highway, such as when the internal combustion engine is operated under a low load state for a long time, the brake usage feeling is deteriorated even when the driver suddenly uses the brake. There is nothing.

[0048] Further, in the time of advancing the valve tine timing to increase the negative pressure in the intake pipe 2, because they gradually changed target advancing angle difference theta _a, it is changed valve tine timing internal combustion The output of the engine does not change rapidly. As a result, the driver can unconsciously obtain a large negative pressure in the intake pipe 2 and the negative pressure tank 11 without causing the driver to feel uncomfortable due to occurrence of longitudinal vibration of the vehicle or the like.

In the above-described processing, the pressure P _T
When the pressure becomes smaller than the predetermined negative pressure P2, a process for increasing the negative pressure in the intake pipe 2 is executed, and when the pressure _PT becomes larger than the predetermined negative pressure P1 larger than the predetermined negative pressure P2, the process is stopped. Since the predetermined negative pressure is provided with hysteresis, it is possible to prevent the processing for increasing the negative pressure in the intake pipe 2 from being performed or to stop the operation from being repeated frequently.

In this embodiment, a pressure sensor 12 is provided in the negative pressure tank 11, and it is determined whether or not to advance the closing timing of the intake valve based on a comparison result between the negative pressure in the negative pressure tank 11 and a predetermined negative pressure. However, a negative pressure sensor may be provided in the intake pipe 2 to determine whether or not to advance the intake valve closing timing based on a result of comparison between the negative pressure in the intake pipe and a predetermined negative pressure. A pressure sensor may be provided in the negative pressure chamber in the booster.

In this embodiment, the pressure sensor 12 for outputting a linear signal in accordance with the negative pressure in the negative pressure tank 11 is provided. However, a pressure switch for generating a high-level or low-level signal at a predetermined negative pressure is provided. It may be provided.

[0052] Although not obtained such effects as those described above, without gradually advancing the target advancing angle difference theta _a in increasing the negative pressure in the intake pipe 2, the intake pipe 2 is a negative pressure The closing timing of the intake valve 10 may be stored in advance so as to be suitable for each internal combustion engine, and the timing may be advanced by a predetermined amount to control the timing. upon a pressure P1 or more, it may be by a predetermined amount retarded without gradually retarding of the target advance angle difference theta _a.

[0053] Further, in accordance with the deviation between the pressure P _T and the predetermined negative pressure P2, the predetermined value α may be variable for incrementally advancing the target advancing angle difference theta _a. Further, although the above-described effects cannot be obtained, a process for increasing the negative pressure in the intake pipe 2 based on whether or not the pressure _PT is larger than the predetermined negative pressure without performing hysteresis at the predetermined negative pressure is executed. Alternatively, it may be determined whether to stop.

[0054]

As described above, according to the present invention, by controlling the closing timing of the intake valve, it is possible to reduce the pumping loss of the intake air, for example, when the internal combustion engine is under a low load. When it is determined that the detection result is on the positive pressure side from the predetermined negative pressure, the closing timing of the intake valve is advanced, so that the negative pressure in the intake pipe can be increased, and a device utilizing the negative pressure in the intake pipe is required. An excellent effect that a normal function can always be achieved is achieved.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a diagram showing an overall configuration of an internal combustion engine provided with a variable valve timing device used in the present invention.

FIG. 3 is a diagram showing a configuration of a variable valve timing device shown in FIG. 2;

FIG. 4 is a flowchart provided for the operation of the variable valve timing device.

FIG. 5 is a flowchart provided for the operation of the variable valve timing device.

FIG. 6 is a diagram showing a relationship between a crank position angle and a cam shaft position angle.

FIG. 7 is a two-dimensional map for setting a target advance angle difference.

FIG. 8 is a diagram showing a predetermined negative pressure P for explaining the operation of FIGS. 4 and 5;
FIG. 4 is a diagram showing a relationship between 1 and a predetermined negative pressure P2.

[Explanation of symbols]

 Reference Signs List 2 intake pipe 3 camshaft 4 variable valve timing device 5 phase converter 10 intake valve 50 electronic control unit (ECU) 11 negative pressure tank 12 negative pressure sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-159427 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 13/02

Claims (2)

(57) [Claims] 1. A valve timing control device for controlling a valve timing for controlling a closing timing of an intake valve of an internal combustion engine, and a closing timing of the intake valve is calculated in accordance with an operation state of the internal combustion engine. First valve timing calculating means for outputting a control signal to the valve timing control device based on the result; a negative pressure tank for introducing a negative pressure in an intake pipe of the internal combustion engine and storing the negative pressure; Negative pressure detecting means for detecting a negative pressure stored in the negative pressure tank; and, based on a detection result of the negative pressure detecting means, determining that the negative pressure in the tank is more positive than a predetermined pressure, the intake valve. comprising closing the second valve timing calculation means for outputting a control signal to the valve timing control device so as to advance the timing of the second Barubutaimi Operating means is the intake valve
Valve timing system to advance the closing timing of the valve
When a control signal is output to the control device, the first valve
Priority to the output of the second timing calculating means.
Using the output of the lubrication timing calculating means.
A valve timing control system for an internal combustion engine, which controls a closing timing of a valve. 2. The second valve timing calculating means, when judging that the negative pressure is on the positive pressure side from a predetermined pressure, sends a control signal to the valve timing control device to gradually advance the closing timing of the intake valve. 3. The valve timing control system for an internal combustion engine according to claim 2 , wherein the system outputs the output.