JPH06272580A - Control of valve timing for internal combustion engine - Google Patents

Abstract

PURPOSE:To change the intake air timing so that generating torque can be changed in response linearly to throttle valve opening. CONSTITUTION:Target torque TQ required by a driver is found (n1-n3) from throttle valve opening (theta) and rotational speed NE of an internal combustion engine, and a spark advance quantity SA of the intake air timing is found (n4) from this target torque TQ and the rotational speed NE. Thereby, when the intake air timing is found (n5) from an intake air quantity by using an air flow meter, since the intake air quantity is saturated, a linear feeling is not produced in obtained torque, on the one hand, when the target torque TQ is used, even if the intake air quantity is saturated, the linear feeling can be given to generating torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for a so-called variable valve timing device capable of changing the operation timing of at least an intake valve of an internal combustion engine.

[0002]

2. Description of the Related Art A variable valve timing device is a device for increasing the operation timing of an intake valve at a high rotation speed as compared with a low rotation speed in order to obtain a high charging efficiency from a low rotation speed region to a high rotation speed region of an internal combustion engine. .

In such a variable valve timing device, in a typical conventional technique, the rotational speed of the internal combustion engine detected by a crank angle sensor and the intake air amount detected by an air flow meter are created in advance as parameters. The optimum timing is read from the stored map, and the timing is controlled so as to be that timing.

[0004]

In the above-mentioned prior art,
Due to saturation of the intake air amount, that is, whether the throttle valve opening is 50% or 100%, for example, there is not much difference in the amount of combustion air actually flowing into the intake pipe. Therefore, if the rotation speed of the internal combustion engine is set to a constant value, the intake air amount becomes saturated with an increase in the throttle valve opening θ as indicated by reference numeral α3 in FIG. The amount data becomes a constant value. As a result, the valve timing cannot be changed as indicated by reference numeral α1a above the saturation point P, and the torque indicated by reference numeral α2a cannot be generated with good linearity with respect to the throttle valve opening. There is a problem.

An object of the present invention is to provide a method of controlling valve timing of an internal combustion engine which can generate torque with good linearity with respect to throttle valve opening.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a valve timing control method for an internal combustion engine, which is capable of changing the rotational timing of at least a camshaft for an intake valve. A method for controlling valve timing of an internal combustion engine, characterized in that the determination is made based on a speed and a desired torque.

[0007]

According to the present invention, in the variable valve timing device capable of changing the rotation timing of at least the camshaft for the intake valve, the rotation timing, that is, the operation timing of the intake valve is set to at least the rotation speed of the internal combustion engine. And the desired torque. The torque is calculated according to the amount of depression of the accelerator pedal.

Therefore, for example, when the rotation speed of the internal combustion engine is constant, the operation timing of the intake valve becomes faster in accordance with the depression amount of the accelerator pedal, and the torque generated by the internal combustion engine also increases linearly. .

[0009]

1 is a block diagram showing an internal combustion engine control apparatus 1 according to an embodiment of the present invention and a configuration related thereto.
The combustion air introduced from the intake port 2 is supplied to the air cleaner 3
After being purified by, the amount of inflow is adjusted via the intake pipe 4 by the throttle valve 5 interposed in the intake pipe 4, and then flows into the surge tank 6. The combustion air flowing in from the surge tank 6 is mixed with the fuel injected from the fuel injection valve 8 interposed in the intake pipe 7, and passes through the intake valve 9 to the internal combustion engine 1
0 into the combustion chamber 11. A spark plug 12 is provided in the combustion chamber 11, and the exhaust gas from the combustion chamber 11 is discharged through an exhaust valve 13 and is discharged from the exhaust pipe 14 into the atmosphere through a three-way catalyst 15.

An intake air temperature detector 21 for detecting the temperature of intake air is provided in the intake pipe 4, and the throttle valve 5
A throttle valve opening detector 22 is provided in relation to the above, and an intake pressure detector 23 that detects the pressure of the intake pipe 7 is provided in the surge tank 6. A cooling water temperature detector 24 is provided near the combustion chamber 11, an oxygen concentration detector 25 is provided upstream of the three-way catalyst 15 in the exhaust pipe 14, and an exhaust temperature is provided inside the three-way catalyst 15. A detector 26 is provided. The rotation speed of the internal combustion engine 10, that is, the rotation speed per unit time is detected by the crank angle detector 27.

The controller 1 includes the detectors 21 to 27.
At the same time, the vehicle speed detector 28, the start detector 29 that detects whether or not the starter motor 33 that starts the internal combustion engine 10 is activated, the air conditioning detector 30 that detects the use of the air conditioner, and the internal combustion engine 10 When the vehicle equipped with is equipped with an automatic transmission, detection results are input from a neutral detector 31 for detecting whether or not the shift stage of the automatic transmission is in the neutral position.

Furthermore, the control device 1 includes a battery 3
4, the control device 1 controls the fuel injection amount and the ignition timing based on the detection results of the detectors 21 to 31 and the power supply voltage of the battery 34 detected by the voltage detector 20. And the like to control the fuel injection valve 8, the spark plug 12, and the like.

The intake valve 9 and the exhaust valve 13 are driven to open and close by a cam shaft (not shown), and the cam shaft is driven by a crank shaft 35 via a timing belt with a timing pulley attached to the cam shaft. Is driven to rotate. A timing conversion means 36 is provided in relation to the intake valve 9, and this timing conversion means 36 is obtained based on the throttle valve opening detected by the throttle valve opening detector 22 as described later. The phase between the timing pulley and the camshaft is changed so that the opening / closing timing is determined corresponding to the target torque to be achieved and the rotation speed of the internal combustion engine 10 detected by the crank angle detector 27.

FIG. 2 is a sectional view of the vicinity of the timing pulley 51 on the intake valve 9 side which constitutes the timing conversion means 36. The timing belt is wound around and meshed with the outer peripheral surface 51a of the timing pulley 51, whereby the timing pulley 51 is rotationally driven without a phase shift with respect to the timing belt.

The base portion 51b of the timing pulley 51 is formed with a cylindrical receiving portion 52 having an inner peripheral surface formed with a helical spline 52a. Corresponding to this, a helical spline 53a is also formed on the outer peripheral surface of the end portion 53b of the cam shaft 53 that drives the intake valve 9 to open and close. These timing pulley 51 and camshaft 53
The piston 54 having an inner peripheral surface corresponding to the helical spline 53a of the camshaft 53 and an outer peripheral surface corresponding to the helical spline 54a of the timing pulley 51. Has been done. The piston 54 is elastically biased in the direction of arrow 56 by a return spring 55.

On the other hand, the piston chamber 5 is provided between the tip portion 54b of the piston 54 and the base portion 51b of the timing pulley 51.
7 is formed, and pressure oil for driving is supplied to the piston chamber 57 via a passage 58 formed in the cam shaft 53. The pressure oil is supplied from an oil switching valve or the like driven by the control device 1. When the pressure oil is supplied, the return spring 55
Against the elastic force of the piston 54
Is driven to be displaced in the direction opposite to the arrow 56, whereby the phases of the piston 54 and the timing pulley 51 and the cam shaft 53 are changed by the helical splines 52a, 53a, 54a. In this way, the amount of displacement of the phase between the timing pulley 51 and the cam shaft 53 can be changed in accordance with the supply amount of the pressure oil, so that the opening / closing timing of the intake valve 9 can be continuously changed.

FIG. 3 is a block diagram showing a specific configuration of the control device 1. The detection results of the detectors 20 to 25 are
It is given from the input interface circuit 41 through the analog / digital converter 42 to the processing circuit 43 realized by a microcomputer or the like. Also, the detector 22,
The detection results of 27 to 31 are the input interface circuit 44.
To the processing circuit 43. Processing circuit 43
A memory 45 for storing various control maps and learning values is provided inside the processing circuit 4.
3, the electric power from the battery 34 is supplied to the constant voltage circuit 4
It is supplied via 6.

The control output from the processing circuit 43 is derived through the output interface circuit 47, is supplied to the fuel injection valve 8 to control the fuel injection amount, and is also supplied to the ignition plug 12 via the igniter 48. Thus, the ignition timing is controlled, the ignition timing is further applied to the timing conversion means 36 to control the opening / closing timing of the intake valve 9, and the fuel pump 32 is driven.

The detection result of the exhaust gas temperature detector 26 is given to the exhaust gas temperature detection circuit 49 in the control device 1. When the detection result is abnormally high, the warning lamp 51 is turned on via the drive circuit 50. To be done.

In the control device 1 configured as described above, the opening / closing timing of the air supply valve 9 is controlled as follows. First, the control device 1 is shown in FIG. 4 in correspondence with the rotational speed NE of the internal combustion engine 10 detected by the crank angle detector 27 and the throttle valve opening θ detected by the throttle valve opening detector 22. The target torque TQ desired by the driver is read from the graph shown in FIG. The graph shown in FIG. 4 is stored in advance in the memory 45 in the control device 1 as a map as shown in FIG. The control device 1 reads the crank angle (° CA) of the optimum advance amount SA from the map shown in FIG. 6 based on the target torque TQ thus obtained and the rotational speed NE. In FIG. 5 and FIG. 6, the portion where the target torque TQ is shown as negative represents the time when the engine brake is operating. Like FIG. 5, FIG. 6 is also stored as a map in the memory 45 in advance.

Thus, the target torque TQ and the rotation speed NE are
By determining the intake timing on the basis of the above, the intake timing becomes faster as the throttle valve opening θ increases, as shown by reference numeral α1 in FIG. Also increases linearly as indicated by the reference symbol α2. However, since the intake air amount is saturated at the opening degree θ1 or more as indicated by the reference numeral α3, the intake timing is indicated by the reference numeral α1a in the conventional technique, and therefore the generated torque is also indicated by the reference numeral α2a. The linearity is impaired as described above.

FIG. 8 is a flow chart for explaining the intake timing control operation as described above. In step n1, the rotational speed NE of the internal combustion engine 10 is obtained from the detection result of the crank angle detector 27, and in step n2, the throttle valve opening θ is detected from the detection result of the throttle valve opening detector 22. In step n3, the above step n
Based on the detection results of 1 and n2, the target torque TQ is read from the map shown in FIG.

At step n4, the advance amount SA of the intake timing is read from the map shown in FIG. 6 based on the target torque TQ and the rotational speed NE, and step n
5, the oil switching valve is controlled so that the read advance amount SA is reached, and the timing pulley 5
The phase of 1 and the cam shaft 53 is controlled so as to be the advance amount SA read in step n4, and the operation is ended.

The target torque TQ may be obtained from the accelerator pedal depression amount, which corresponds to the throttle valve opening θ, and the timing conversion means 36.
The phase of the timing pulley 51 and the cam shaft 53 may be changed by a method other than hydraulic pressure.

Furthermore, the amount of depression of the accelerator pedal is electrically detected, and the throttle valve is driven and controlled by an actuator such as a motor in accordance with the detection result, so-called electronic throttle or fly-by.・ In the case of devices called wires,
An arbitrary linear or non-linear relationship can be provided between the depression amount and the throttle valve opening. Depending on such a configuration, the target torque TQ can be arbitrarily set according to the depression amount of the accelerator pedal. can do.

[0026]

As described above, according to the present invention, the operation timing of the intake valve is determined at least on the basis of the rotational speed of the internal combustion engine and the desired torque. The actual generated torque can be linearly obtained corresponding to the desired torque.

[Brief description of drawings]

FIG. 1 is a block diagram showing a control device 1 for an internal combustion engine of an embodiment of the present invention and a configuration related thereto.

FIG. 2 is a cross-sectional view of the vicinity of a timing pulley 51 that constitutes the timing conversion means 36 of the embodiment of the present invention.

FIG. 3 is a block diagram showing a specific configuration of the control device 1.

FIG. 4 is a graph showing a relationship between a throttle valve opening θ and a rotational speed NE and a target torque TQ.

FIG. 5 is the map of FIG.

FIG. 6 is a map showing intake timing corresponding to the target torque TQ and the rotational speed NE.

FIG. 7 is a graph showing the relationship between the intake air amount, the intake timing, and the generated torque corresponding to the throttle valve opening θ.

FIG. 8 is a flowchart for explaining an intake timing control operation.

[Explanation of symbols]

 1 Control device 5 Throttle valve 9 Intake valve 10 Internal combustion engine 20-31 Detector 35 Crankshaft 36 Timing conversion means 51 Timing pulley 53 Camshaft

Claims (1)

[Claims] 1. A method for controlling a valve timing of an internal combustion engine capable of changing the rotational timing of at least a camshaft for an intake valve, wherein the rotational timing is at least a rotational speed of the internal combustion engine and a desired torque. A method for controlling valve timing of an internal combustion engine, characterized in that it is determined based on the above.