JPH03217657A - Ignition timing control device for engine - Google Patents

Abstract

PURPOSE:To effectively restrain and prevent the occurrence of shock at the time of operations except idling, by receiving the output of an operating condition detecting means, and thereby limiting a degree of slow change of target ignition timing at the transient time in a transient ignition timing operation means at the time of idling. CONSTITUTION:As a limiting means 26 is out of action when an engine is in operation except idling, ignition timing is thereby slowly changed toward a target ignition timing in accordance with the target ignition timing at the transient time. This thereby allows the combusting condition of air-fuel mixture to be slowly changed in such a way that torque produced is smoothly changed, which will thereby never produce any shock. On the contrary, the limiting means 26 is in operation at the time of idling, the degree of slow change in the target ignition timing at the transient time is limited to a greater extent than in engine operating conditions except idling. This thereby causes the produced torque to be quickly increased when an engine load is abruptly increased, for example, when an on-vehicle air-conditioner is actuated at the time of idling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ignition timing control device for an engine, and particularly to measures for improving idle stability.

(Prior Art) Conventionally, when controlling the ignition timing to change the ignition timing of the air-fuel mixture to the optimum ignition timing depending on the engine operating condition, depending on the engine operating condition, the ignition timing may be adjusted depending on the engine operating condition. If the change is made abruptly, the combustion state of the air-fuel mixture will change greatly, causing a large change in the generated torque value and causing a shock felt by the passengers. In the engine disclosed in Japanese Patent Publication No. 45309, the ignition timing is gradually changed toward the optimum value to smooth the change in the generated torque.

(Problems to be Solved by the Invention) However, it has been found that the above-mentioned conventional device has the following drawbacks. In other words, when the engine is running at idle,
If the engine speed is low and unstable, and the ignition timing is controlled to change slowly, for example, when an on-board air conditioner starts operating, the ignition timing will gradually change even though the engine load increases rapidly. As the engine speed changes, the generated torque also increases gradually and instantly becomes large.As a result, a sudden drop in the idle speed cannot be suppressed, which has the disadvantage of causing the engine to stall.

The present invention has been made in view of the above, and its purpose is to effectively suppress the occurrence of shock caused by sudden changes in ignition timing, and also to suppress sudden changes in idling speed during idling operation. The purpose is to prevent the decline.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the ignition timing is gradually changed during engine operation other than idling operation, and the ignition timing is gradually changed during idling operation. We will try to limit the extent of changes and make changes relatively quickly.

In other words, the specific solution of the present invention includes an operating state detecting means for detecting the operating state of the engine, and an ignition timing for calculating the target ignition timing of the spark plug according to the operating state detected by the operating state detecting means. a calculation means, a transient ignition timing calculation means for calculating a target ignition timing during a transient period so as to gradually change toward the target ignition timing calculated by the ignition timing calculation means, and the transient ignition timing calculation means when changing the ignition timing. The ignition timing control device for an engine is assumed to be equipped with a control means for controlling ignition timing so that the air-fuel mixture is ignited at the transient target ignition timing calculated by . and,
A restricting means is provided for receiving the output of the driving state detecting means and restricting the degree of gradual change in the target ignition timing in the transient ignition timing calculating means during idling operation.

(Function) With the above configuration, in the present invention, the limiting means does not operate during engine operation except during idling operation, so that the ignition timing is gradually adjusted toward the target ignition timing in accordance with the target ignition timing during transition, as in the conventional case. Since the combustion state of the air-fuel mixture changes gradually, the generated torque changes smoothly and no shock occurs.

On the other hand, during idling operation, the limiting means operates to limit the degree of gradual change in the target ignition timing during transient times, and the degree of change becomes larger than in operating states other than the above-mentioned idling time. Therefore, even if the engine load suddenly increases during idling, for example due to the activation of the on-board air conditioner, the generated torque value will quickly increase, effectively suppressing the sudden drop in the idling speed and causing the engine to stall. There isn't.

(Effects of the Invention) As explained above, according to the engine ignition timing control device of the present invention, the degree to which the ignition timing is gradually changed is made different during idling operation and during other operations. ,
It is possible to effectively suppress and prevent the occurrence of shock during driving other than idling, and even when the engine load suddenly increases during idling, it is possible to effectively suppress a sudden drop in the idle speed and prevent engine stalling.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, ]. 2 is an engine, 2 is a combustion chamber whose volume is variable by a piston 4 slidably inserted into a cylinder 3 of the engine 1, and 5 has one end communicating with the atmosphere and the other end opening into the combustion chamber 2. An intake passage 6 for supplying intake air is an exhaust passage whose one end communicates with the combustion chamber 2 and whose other end is open to the atmosphere to discharge exhaust gas. The intake passage 5 includes a throttle valve 7 for adjusting the amount of intake air;
A fuel injection valve 8 for injecting and supplying fuel is disposed downstream of the throttle valve 7, and a catalyst device 9 for purifying exhaust gas is disposed in the exhaust passage 6. Furthermore, in the combustion chamber 2, an intake valve 10 is provided at the opening of the intake passage 5.
Exhaust valves 11 are arranged at the openings of the exhaust passages 6, and spark plugs 12 for igniting the air-fuel mixture in the combustion chamber 2 are arranged at the top. In addition, 13 is an ignition coil that generates high voltage, and 14 is a power distributor that distributes the high voltage of the ignition coil 13 to the spark plug of the cylinder that is in the combustion stroke, and that controls the crank angle (engine speed). It also functions as a rotation speed sensor.

In addition, 15 is a hot-wire type air flow sensor that detects the amount of intake air; 16 is an idle switch that is turned on when the throttle valve 7 is fully opened to detect when the engine 1 is running at idle; 14 and/or the air flow sensor 15, the engine 1
Operating state detection means 22 configured to detect the operating state of
It consists of

The detection signals from each of the sensors described above are input to a controller 20 having an internal CPU and the like. The controller 2
0 adjusts the amount of fuel injected from the fuel injection valve 8, and also adjusts the ignition timing of the air-fuel mixture in the combustion chamber 2 by the ignition plug 12 by adjusting the output timing of the ignition signal to the ignition coil 13. Function.

Next, the control of ignition timing by the controller 20 will be explained based on the control flow shown in FIG. 2.

In the figure, after the engine starts and the detection signals from the above-mentioned sensors are read in step S1, step S2 determines that the engine is running at idle, that is, when the engine speed is below a predetermined low rotational speed and the throttle valve 7 is fully closed. In step S3, the basic ignition timing IGB is calculated and set according to the engine speed and the engine load (intake air amount) from a pre-stored map. A correction amount IOC is calculated based on the engine coolant temperature, etc., and the target final ignition timing IG is calculated by adding and correcting the basic ignition timing IGB calculated above with the correction amount IOC in step S5.

After that, the current value I of the target final ignition timing IG
Average value JIG of C(i) and previous value I C(i-1)
(i)+I G(i-1))/2 is calculated, the result of the calculation is set as the final ignition timing IG during the transient period, and the value during the transient period is set smaller than the final value (target value). In step S7, the ignition coil 1 is set so that the mixture is ignited at the final ignition timing IC during this transition.
Control 3 and return.

On the other hand, in the case of idling operation in step S2, the idle rotation speed is feedback-controlled to the target rotation speed by controlling the ignition timing in step S8 and thereafter. That is, in step S8, the basic ignition timing I during idling operation is
The GID is set from a preset map according to the engine speed, and in step S9 the target engine speed No. is set to a higher speed as the engine coolant temperature is lower, as shown in Fig. 3, and the actual engine speed is set in step SIO. The rotational deviation ΔNe (-Ne-No) between the rotational speed Ne and the target rotational speed NO is calculated, and in step Sl+, the minute amount ΔGfb for feedback control of the ignition timing is calculated based on the map in FIG. The larger the value, the larger the value, and this minute amount ΔGfb
is added to the previous feedback correction amount IGfb(1-1) to obtain the current feedback correction amount IGfb, and a basic ignition timing correction amount IOC is calculated in step SI2.

After that, only when the in-vehicle air conditioner starts operating.
Annealing to the target ignition timing will be prohibited. In other words, the state of the in-vehicle air conditioner is determined in step SI3,
If it is in the OFF state, in step S+4, the final ignition timing IC is set based on the basic value ICID, the feedback correction value IGfb, and the correction amount IOC.
After calculating = IGID + IGfb + IGC, the process returns to step S6 and smoothing processing to the target ignition timing is performed.

On the other hand, if the in-vehicle air conditioner is in the ON state in step S+3, the previous state of the in-vehicle air conditioner is determined in step Sl5, and if it was in the OFF state last time, it is determined that it is time to start operating the in-vehicle air conditioner, and step After the timer T is set as the time for prohibiting the smoothing process in SI6, until the timer T reaches zero value in step S+7,
While decrementing this timer value in step S+8, the final ignition timing IC is changed in step Sl9 to the step 8 above.
14, and control the ignition coil 13 in step S7 to achieve this final ignition timing IG.
Return.

Therefore, in the control flow of FIG. 2 above, step S
5 and SI4 constitute an ignition timing calculating means 23 which calculates the final target ignition timing IC of the spark plug 12 according to the engine operating state detected by the operating state detecting means 22, and also includes step S6. Accordingly, the transient ignition timing is calculated by performing smoothing processing so as to gradually change toward the final target ignition timing IC calculated by the ignition timing calculation means 23, and calculating the final target ignition timing during the transition. It constitutes the calculation means 24. Also,
In step S7, when changing the ignition timing, the ignition coil 13 is controlled to ignite the air-fuel mixture at the transient target ignition timing calculated by the transient ignition timing calculating means 24, thereby controlling the ignition timing. It constitutes the control means 25. Further, by immediately proceeding from step SI9 to step S7 in the same control flow, the degree of gradual change to the target ignition timing in the transient ignition timing calculation means 24 is limited during the idling operation detected by the operating state detection means 22. The limiting means 26 is configured to immediately set the target ignition timing IG to the final target ignition timing IG.

Therefore, in the above embodiment, when the engine is operating other than when idling, the target final ignition timing IG is smoothed, and the actual ignition timing of the air-fuel mixture is adjusted according to the target final ignition timing IG during the transient period. Since the value of the generated torque changes gradually toward , the value of the generated torque does not change suddenly and greatly, and the shock felt by the vehicle occupant is effectively suppressed or prevented.

On the other hand, during idling, the idling speed Ne is feedback-controlled to the target speed NO by adjusting the ignition timing, but when the on-board air conditioner starts operating, the engine load suddenly increases and the idling speed is This tends to cause a sudden drop in rotational speed. However, in this case, as shown in Fig. 5, the ignition timing annealing process is prohibited and the ignition timing is immediately controlled to the calculated final target ignition timing IG. The combustion condition of the engine is adjusted to a favorable one in a short period of time, and the generated torque suddenly increases. As a result, a sudden drop in idle speed is quickly suppressed, and engine stalling is effectively prevented.

In the above embodiment, gradual changes in the ignition timing are prohibited during idling operation, but it is of course possible to limit the extent to which the ignition timing is changed gradually. In addition, in the above embodiment, the idle rotation speed Ne was feedback-controlled to the target value NO by the ignition timing during idle operation.
Needless to say, the present invention can be similarly applied to engines that do not perform this control.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is an overall configuration diagram, FIG. 2 is a flowchart showing ignition timing control, and FIG. 3 is a diagram showing target rotation speed characteristics in idle rotation speed control.
FIG. 4 is a characteristic diagram of the minute correction amount taken for the rotation speed deviation in feedback control of the idle rotation speed, and FIG. 5 is an explanatory diagram of the operation. 1...Engine, 12...Spark plug, 13...
Ignition coil, 14... Rotation speed sensor, 15... Air flow sensor, 20... Controller, 22... Operating state detection means, 23... Ignition timing calculation means, 24... Transient ignition timing calculation Means, 25... Control means, 26... Limiting means. 2 idiots

Claims (1)

[Claims] (1) An operating state detecting means for detecting the operating state of the engine, an ignition timing calculating means for calculating a target ignition timing of the spark plug according to the operating state detected by the operating state detecting means, and an ignition timing calculating means for calculating the target ignition timing of the spark plug according to the operating state detected by the operating state detecting means. a transient ignition timing calculating means for calculating a transient ignition timing so as to gradually change toward the calculated target ignition timing; and a transient target ignition timing calculated by the transient ignition timing calculating means when changing the ignition timing. control means for controlling the ignition timing so as to ignite the air-fuel mixture at the time of idling; 1. An engine ignition timing control device, comprising: limiting means for limiting the degree of change.