JPH0440550B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ignition timing control device that controls the ignition timing of an engine. Corrects the ignition timing to compensate for the response delay of the opening/closing valve during transient operation of the engine, in engines where the secondary side intake passage has an opening/closing valve that is controlled to open and close according to the amount of intake air. Regarding measures to be taken.

(Prior Art) Conventionally, as an engine intake system, as disclosed in, for example, Japanese Unexamined Patent Publication No. 55-12261, an intake passage downstream of a throttle valve is divided into a primary intake passage and a secondary intake passage. An on-off valve is interposed in the secondary side intake passage, and an on-off valve control device is provided to control the opening and closing of the on-off valve in response to increases and decreases in the amount of engine intake air, so that the amount of intake air is small. Sometimes, by closing the on-off valve and supplying intake air to the engine only from the primary intake passage, the intake air velocity is increased and swirl is generated in the combustion chamber, improving combustibility during low-load operation. When the amount of intake air is large, intake air is supplied from the secondary intake passage in addition to the above-mentioned primary intake passage, thereby increasing the filling efficiency of intake air into the combustion chamber and improving output during high-load operation. What has been done is known.

(Problem to be Solved by the Invention) Generally speaking, an engine is equipped with an ignition timing setting device that sets the ignition timing to a value suitable for steady operation of the engine based on engine speed, intake negative pressure, etc. Ignition is performed based on ignition timing set by a timing setting device. However, in engines equipped with the above-mentioned conventional intake system, the ignition timing is quickly controlled to an appropriate value by the electrical processing speed during so-called transient operation such as acceleration or deceleration of the engine. On the other hand, the opening/closing valve is controlled to open/close with a delay depending on the mechanical processing speed, and the time lag between the two causes the combustion state of the engine to become unstable. Ignition causes the fuel to ignite prematurely, causing knocking. On the other hand, during deceleration operation, ignition while a relatively weak intake swirl occurs reduces combustibility, resulting in a half-misfire state, causing problems such as car bucking. It was hot.

An object of the present invention is to correct the response of the on-off valve during transient operation by correcting the ignition timing during transient operation of the engine in an engine having an intake system in which an on-off valve is provided in the secondary intake passage as described above. The purpose is to eliminate instability in drivability caused by delays.

(Means for Solving the Problems and Their Effects) In order to achieve the above object, the solving means of the present invention are as follows:
As shown in FIG. 1, the intake passage 7 downstream of the throttle valve 13 is formed into a primary intake passage 7a and a secondary intake passage 7b, and an on-off valve 16 is interposed in the secondary intake passage 7b. It also includes an on-off valve control device that controls opening and closing of the on-off valve 16 in response to increases and decreases in the amount of intake air, and an ignition timing setting means that sets the ignition timing to a value suitable for steady operation of the engine 1. In the engine 1, which performs ignition based on the ignition timing set by the timing setting means, transient operation such as acceleration or deceleration is detected by the transient operation detecting means, and the ignition timing is set. The ignition timing that is set corresponding to the steady operation of the engine is adjusted by the ignition timing correction means,
During acceleration operation, the angle is corrected to the retard side in accordance with the delay in the operation of the on-off valve, and during acceleration operation, the angle is corrected to the advance side in accordance with the delay in the operation of the on-off valve.

(Effects of the Invention) Therefore, according to the present invention, during transient operation of an engine having an intake system in which an on-off valve is provided in the secondary intake passage, the ignition timing is accelerated in accordance with the delay in operation of the on-off valve. The angle is corrected to the retard side during operation and to the advance side during deceleration operation, and each accurately corresponds to the strength of the intake swirl, so it is possible to maintain a stable combustion state during transient engine operation. It is possible to prevent knocking during acceleration and car bucking during deceleration.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described in detail based on the drawings from FIG. 2 onwards.

FIG. 2 shows the overall structure of the first embodiment of the present invention, in which 1 is an engine having a combustion chamber 6 formed by a cylinder 3 in a cylinder block 2, a piston 4 and a cylinder head 5; 8 is an intake passage that supplies intake air to the chamber 6; 8 is an exhaust passage that discharges exhaust gas from the combustion chamber 6; 9 is an intake valve; 10 is an exhaust valve; 11 is a camshaft 12 that opens and closes the intake and exhaust valves 9 and 10. It is a valve train mechanism having the following functions. A throttle valve 13 is provided in the middle of the intake passage 7, and a fuel injection valve 14 is provided downstream thereof.
The intake passage 7 downstream of the throttle valve 13 is connected to the partition wall 1
5 into a primary side intake passage 7a having a relatively small passage area and a secondary side intake passage 7b having a relatively large passage area. An on-off valve 16 for opening and closing the passage 7b is interposed in the secondary intake passage 7b, and an actuator 17, which is made of, for example, a diaphragm device using negative pressure as an operating source, is drivingly connected to the on-off valve 16. .

Further, 18 is an engine rotation speed sensor that detects the engine rotation speed based on the rotation speed of the camshaft 12, and 19 is an intake passage 7 downstream of the throttle valve 13.
20 is a water temperature sensor that detects the engine 1 cooling water temperature; and 21 is an opening/closing valve opening sensor that detects the opening of the opening/closing valve 16. Each of these sensors 18~
The output signal of 21 is input to a control unit 24 equipped with a microcomputer, and the control unit 24 controls the actuator 17 for driving the fuel injection valve 14 and opening/closing valve 16.
The operation of the ignition coil 23 built into the power distributor for applying high voltage for ignition to the spark plugs 22, 22, . . . is controlled. That is, the control unit 24, the engine rotation speed sensor 1
Engine rotation speed signal from 8 and negative pressure sensor 19
The on-off valve control function detects the amount of intake air taken into the engine 1 based on the negative pressure signal from the engine 1, and controls the opening and closing of the on-off valve 16 in response to an increase or decrease in the intake air amount, and the engine rotation speed signal and An ignition timing setting function that detects the steady operating state of the engine 1 based on a negative pressure signal and sets the ignition timing to a value corresponding to the steady operating state, and a A transient operation detection function detects so-called transient operation during acceleration and deceleration of the engine 1, and an ignition timing that is set by the ignition timing setting function according to the delay in operation of the on-off valve 16 during acceleration operation of the engine 1. an ignition timing correction function that corrects the ignition timing to the retard side and also corrects the ignition timing set by the ignition timing setting function to the advance side according to the delay in operation of the on-off valve 16 during deceleration operation, and the engine rotation speed signal. and the fuel injection valve 1 according to the operating state of the engine 1 detected based on the negative pressure signal.
4, and a water temperature correction function that corrects the ignition timing, fuel injection amount, etc. based on the water temperature signal from the water temperature sensor 20. Note that 25 is a battery.

Next, the operation of the above embodiment will be explained with reference to the control flowcharts shown in FIGS. 3 and 4. The entire control flow is performed according to the flowchart shown in FIG. 3. That is, after the start, the system is initialized, and then the engine speed signal from the engine speed sensor 18, the negative pressure signal from the negative pressure sensor 19, the water temperature signal from the water temperature sensor 20, and the on-off valve opening sensor 21 are transmitted. Each data of the opening/closing valve opening signal is input. After this, it is determined that the engine 1 is not in a stopped state, and if this determination is YES, the basic fuel injection amount is read from the basic fuel injection amount map based on the engine speed and intake negative pressure, and this Water temperature correction and acceleration/deceleration (negative pressure change) for basic fuel injection amount
After performing each correction process in order, the fuel injection amount is converted into pulses, and then the opening/closing valve 16 is adjusted to the target opening determined by the opening/closing valve target opening map for the engine speed and intake negative pressure. After controlling, the flow moves to the ignition timing advance angle calculation flow. On the other hand, if the above judgment is NO, an offset process is performed to correct the variation in the fully closed position of the on-off valve 16, and then the process moves to the advance angle calculation flow via the on-off valve control step.

The advance angle calculation flow described above is performed according to the flowchart shown in FIG. That is, first, the ignition timing advance standard value θo is read from the advance angle map based on the engine speed and intake negative pressure, and then the correction value θw is calculated according to the cooling water temperature. The advance angle value θt corresponding to the target on-off valve opening obtained in the above on-off valve control step is read out from the required ignition timing basic map as shown in the figure.
Furthermore, the advance angle value θr corresponding to the actual opening/closing valve opening is read from the required ignition timing basic map, and then the advance angle values θt and θr are subtracted (θr−θt) to obtain the delay amount θs (minus value). ), and finally the above reference value θo,
The water temperature correction value θw and the delay amount θs are added to form the actual advance value θ, and the ignition timing is set based on this advance value θ. The advance angle calculation flow is thus completed, and then the process returns to the data input step of the overall flow shown in FIG.

Therefore, in this case, during acceleration operation of the engine 1, the operation of the on-off valve 16 is determined by comparing the advance angle value θt corresponding to the target opening degree of the on-off valve 16 with the advance angle value θr corresponding to the actual opening degree. Since the ignition timing is delayed by the amount θs corresponding to the delay, during acceleration operation when the opening degree of the on-off valve 16 is small due to the delay in operation and a strong intake swirl is generated due to the supply of intake air from the primary intake passage 7a. Even if this occurs, the ignition timing can be maintained appropriately, thereby preventing the occurrence of knocking during accelerated operation.

FIG. 6 shows a second embodiment, in which the advance angle calculation flow in the first embodiment is modified, and the other components have the same configuration as the first embodiment.

That is, in this embodiment, in the advance angle calculation flow, the advance angle reference value θo of the ignition timing is determined from the advance angle map.
After reading out, the current and previous intake negative pressures P and P' detected each time the control loop transition is repeated are detected. Next, based on this negative pressure change, it is determined whether or not the engine 1 is in an accelerating operation state, that is, dp/
It is determined whether dt is larger than the reference value α (dp/dt>α), and if this determination is YES, a predetermined time T is stored in the memory n, and then a certain delay from the advance angle reference value θo is performed. The actual lead angle value θ is obtained by subtracting the amount θk, and the point angle timing is set based on this lead angle value θ.

On the other hand, if the above judgment is NO, memory n
It is determined that is not zero, and since n=0 at the time of the first loop transition, the ignition timing is advanced by using the actual advance value θ as the advance reference value θo. On the other hand, in the second and subsequent loops, n≠0, so after reading n-1 into the memory n, the actual lead angle value θ (=θo=
θk). Then, the advance angle correction is performed by this delay amount θk until the memory n becomes zero, that is, until the predetermined time T elapses, and the control is thus completed.

Therefore, in this embodiment, the ignition timing of the engine 1 is retarded by the delay amount θk until a predetermined time T has elapsed from the time when the engine 1 is in accelerated operation.
The ignition timing can be corrected using a so-called expected retard, and as in the first embodiment, the imbalance in the ignition timing due to the delay in the operation of the on-off valve 16 during acceleration operation of the engine 1 is corrected to prevent the occurrence of knocking. It can be prevented.

In each of the above embodiments, the ignition timing is corrected to the retarded side when the engine 1 is running at high speed to prevent knocking, but conversely, when the engine 1 is running at deceleration, the ignition timing is adjusted to the late side to prevent knocking. By correcting to the side, it is possible to compensate for the inactivity of the intake swirl due to the delay in the operation of the on-off valve 16, improve combustibility, and prevent car barking from occurring.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is an overall configuration diagram of the first embodiment, FIG. 3 is an overall diagram of the control flowchart, and FIG. 4 is an explanatory diagram of the advance angle calculation flowchart. FIG. 5 is an explanatory diagram of the basic required ignition timing map, and FIG. 6 is a diagram corresponding to FIG. 4 showing the second embodiment. 1...Engine, 7...Intake passage, 7a...1
Next side intake passage, 7b... Secondary side intake passage, 13...
...throttle valve, 16...opening/closing valve, 17...actuator, 18...engine speed sensor, 1
9... Negative pressure sensor, 20... Water temperature sensor, 21...
...Opening/closing valve opening sensor, 24...Control unit.

Claims (1)

[Claims] 1 The intake passage downstream of the throttle valve is formed into a primary intake passage and a secondary intake passage, and an on-off valve is interposed in the secondary intake passage, and the on-off valve corresponds to an increase or decrease in the amount of intake air. and an ignition timing setting means for setting the ignition timing to a value suitable for steady operation of the engine, and ignition is performed based on the ignition timing set by the ignition timing setting means. In such an engine, there is provided a transient operation detection means for detecting a transient operation of the engine, and when the transient operation detection means detects acceleration operation, the ignition timing setting means according to the delay in operation of the on-off valve. The ignition timing set by the ignition timing setting means is corrected to the retarded side, and when deceleration operation is detected, the ignition timing set by the ignition timing setting means is corrected to the advanced side in accordance with the delay in operation of the on-off valve. 1. An ignition timing control device for an engine, comprising ignition timing correction means.