JPS63198748A - Engine speed control method - Google Patents

Abstract

PURPOSE:To prevent the occurrence of an engine stop, by a method wherein an ignition timing, where a lag in response to production of torque during idle running is low, is corrected according to a fluctuation in the engine speed, and when an engine speed has a tendency for lowering, its correction amount is increased over that available during rise. CONSTITUTION:An air control valve 30 located between air conduits 18 and 19 situated in a intake air passage in a manner to run around a throttle valve 16 is opened and closed by displacing a diaphragm 33 by means of difference in a pressure between a diaphragm chamber 37 and an atmosphere pressure chamber 38. Further, the opening of a vale body 35 is controlled by regulating a pressure in a diaphragm chamber 37 through control of a solenoid valve 51 in an atmosphere conduit 47. The solenoid valve 51 is controlled together with an ignition deice 60 by means of a control device 20, and the control is effected so that an ignition timing is corrected according to the degree of a decrease and an increase in the engine speed during idle running. The correction amount is set so that an engine speed, having a tendency for lowering, is increased over that available when it has a tendency for a rise.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for controlling the engine speed when the engine is in an idle state, in which the engine speed is controlled to prevent a drop in the engine speed due to changes in the load of an air conditioner, etc., and to prevent fluctuations in the idle speed. Regarding control method.

Conventionally, methods for controlling engine speed at idle include manipulating the amount of intake air (including the amount of mixture) or the degree of mixture (air-fuel ratio) to prevent a drop during load fluctuations; Various control methods have been proposed to prevent rotational speed fluctuations.

In this conventional method, response delays in the intake system and fuel system are dominant, so even if a drop or fluctuation in engine speed is detected and the intake air amount, fuel amount, or mixture amount is added, The added amount generates torque that effectively acts against drops and fluctuations in engine rotational speed only after the rotational speed has decreased to the level determined by the absence of each additional amount, and is particularly effective against sudden changes. It was small. Furthermore, if the control amount is exceeded, problems such as interfering with air-fuel ratio feedback control, resulting in a diffusion system, and disturbance of the air-fuel ratio and occurrence of hunting, may occur.

The present invention has been made in view of the above-mentioned problems, and detects a decrease or increase in engine rotation speed in a system that adjusts the amount of air-fuel mixture to the engine during idling to control the engine rotation speed to a desired value. In this way, the ignition timing with less delay in response to torque generation during engine idling is corrected according to the degree of decrease or increase in rotational speed, and when the rotational speed is on the decreasing side, the ignition timing is corrected more than when it is on the increasing side. By increasing the amount and making it asymmetrical, this engine prevents engine stalling, greatly improves responsiveness when engine speed changes, and greatly reduces the occurrence of dips and fluctuations in engine speed. The purpose is to provide a rotation speed control method.

An embodiment of an apparatus for carrying out the control method according to the present invention will be described below. In this example, the method of the present invention is applied to an engine control device equipped with an electronically controlled fuel injection mechanism, and also equipped with an air passage that bypasses the throat valve and a mechanism for controlling the air flow rate. This is an indication. Of course, the present invention is also applicable to idle adjustment devices that include a carburetor or do not include a bypass air passage.
For example, it can be similarly applied to a device that adjusts the opening degree of a throttle valve, etc.).

An embodiment shown in the drawings will be described below.

In this embodiment, when the engine is idling, the air flow rate control of the bypass air passage and the ignition timing control are used together to control the engine rotation speed.

In FIG. 1, an engine 10 is a known four-stroke spark ignition engine for driving an automobile, and an air cleaner 1
1, air flow meter 12, intake pipe 13, intake branch pipe 14
The fuel, for example gasoline, is injected and supplied from a plurality of electromagnetic fuel injection valves 15 provided in the intake branch pipe 14. .

The main intake air amount of the engine 10 is adjusted by a throttle valve 16 that is arbitrarily operated by an accelerator pedal (not shown), while the fuel injection amount is adjusted by a microphone t-cocomputer 20. microphone lj computer 20
determines the fuel injection amount using the rotational speed detected by the electromagnetic bicycle 21, which is a rotational speed sensor installed in the distributor 24, and the intake air amount measured by the airflow meter 12 as basic parameters. This is a known system that also inputs signals from a warm-up sensor 22, etc. that detects the engine cooling water temperature, and thereby increases or decreases the amount of fuel injection 11'. Also, throttle switch 1
Reference numeral 7 detects whether the throttle valve 16 is fully closed, almost fully closed, or fully opened.

The air conduits 18, 19 are connected to the throttle valve (5) to connect the throttle valve (6), and an air control valve 30 is provided between the side conduits (18, 19). Further, one end of the conduit 19 is connected to an air inlet provided between the throttle valve 16 and the air flow meter 12, and one end of the conduit 19 is connected to an air outlet provided downstream of the throttle valve 16. has been done.

The air control valve 30 is a diaphragm two control valve in this case, and the swinging of a diaphragm 33, which is sandwiched between housings 31 and 32, is controlled by a valve body 3 fixed to a shaft 34.
5 to open and close the valve seat 36. The diaphragm 33 has a diaphragm chamber 37. It is displaced by the pressure difference between the atmospheric pressure chambers 38 and is biased by a compression coil spring 39, thereby applying a valve opening force to the valve body 35.

The valve body 35 is basically a needle valve, and the valve seat 36
The amount of air flowing from the inlet vibe 41 to the outlet vibe 42 is adjusted by continuously changing the flow area formed by the diaphragm 33 according to the displacement of the diaphragm 33, that is, the pressure in the chamber 37. Further, the valve body 35 is arranged opposite to a normal needle valve, and a valve closing force is applied by a relatively weak compression coil spring 43.

The valve body 35 is arranged in the opposite direction to that of a normal needle valve, and opens when the pressure in the chamber 37 increases (approaches atmospheric pressure), and the pressure in the chamber 37 decreases (approaches vacuum). and close the valve. Furthermore, assuming that the lift amount (displacement amount) of the valve body 35 is O at the fully open position shown in FIG. ing.

A holding plate 44 is fixed to the housing 32, and the shaft 34 is guided by this holding plate 44 and a support hole 45 at the bottom.

Further, a small hole 46 is formed in the holding plate 44, and the atmosphere is introduced into the atmospheric pressure chamber through this small hole 46 within three days.

The diaphragm chamber 37 is connected to a boat 48 upstream of the throttle valve 16 via a pipe 47 to introduce atmospheric pressure, and to an intake branch pipe downstream of the throttle valve 16 via a pipe 49 and a throttle 50 to introduce negative pressure. 14.

An on/off type solenoid valve 51 is provided in the middle of the pipe 47 to open and close the pipe 47 and control the pressure in the diaphragm chamber 37 .

The electromagnetic valve 51 is connected to the microcomputer 20, which controls the excitation of the electromagnetic coil 52. The air control valve 30 may also be constructed using a linear electromagnetic control valve, a step morph control valve, or the like.

The microcomputer 20 has an electromagnetic pickup 21.
Warm-up sensor 22. It is connected to the air conditioning switch 23 of an air conditioner such as a car cooler, and inputs an engine rotation speed signal, a cooling water temperature signal, an air δ1/1 unit on/off signal, and in addition to this, an engine 10 The starter signal STA, and the neutral safety signal NSS of the automatic transmission are input.

Here, the electromagnetic pickup 21 is provided facing a ring gear 2L> that rotates in synchronization with the crankshaft of the engine 10, and receives a pulse signal having a frequency proportional to the engine rotational speed (in the case of this embodiment, the crank angle (occurs every 30 degrees). The warm-up sensor 22 is made up of a temperature sensing element such as a thermistor, and detects, for example, the temperature of cooling water, which is representative of engine salt. Further, although not shown, the distributor 24 includes a known structure for distributing high voltage power to each spark plug 25. In addition, the ignition device 26
receives a signal instructing the ignition timing and energization time from the microcomputer 20 and generates a high voltage according to the signal, and an igniter (ignition control device) is connected to -C.
It consists of an ignition coil and an ignition coil.

Also, when the air conditioning switch 23 is turned on, the electromagnetic clutch 2
7 is in a connected state, and the air conditioner compressor 28 is connected as a load of the engine 10.

Further, the vehicle speed meter 29 generates a pulse signal proportional to wheel rotation.

Next, the computer 20 shown in FIG. 2 will be explained.

The microprocessor (CPU) 100 is a known 8.12 or 16-bit microprocessor that calculates control amounts for ignition timing, fuel injection amount, and idle rotation according to a predetermined program.

Human power counter], OI is the rotation speed N to the CPU 100.
It is used to send data representing the data to c p u +, o o, and the data is obtained by counting clock pulses based on the pulse signal from the electromagnetic pickup 21. Also,
This counter 101 sends an interrupt command signal to the interrupt control section 102 in synchronization with engine rotation. When the interrupt control unit 102 receives this signal, it outputs an interrupt signal to the CPU 100 through the bus 150.

The input boat 103 inputs signals from each sensor to a lotus 150.
It is for transmitting data to CPU via A/D converter, multiplexer, etc.
Intake air amount signal AFM from the airflow meter 12, cooling water temperature signal T I-(W) from the warm-up sensor 22, air conditioner signal Δ/C1 from the idle speed switch 23, automatic transmission natural safety switch (not shown) Neutral signal NSS from.

A vehicle speed signal SPD from a vehicle speed meter 29, a starter signal ST from an engine start switch, etc. are input.

The power supply circuits 104 and 105 are circuits that make the output voltage of the on-vehicle batch IJ 60 a constant voltage, and the power supply circuit 104 is connected to the battery 60 via the engine key switch 61.
The other power supply circuit 105 is directly connected to the battery 60. Then, the power supply circuit 105 constantly applies voltage to the random access memory 106, and the power supply circuit 104 applies a voltage to the random access memory 106.
When the key switch 61 is turned on, voltage is applied to the units 1- other than 06.

Random access memory (RAM) 106, 107 is
This is a readable/writable memory that is temporarily used by the CPU 100 when executing a program, and the RAM 106 has a configuration in which the stored contents will not be lost even if the key switch 61 is turned off and the engine operation is stopped because voltage is applied thereto. It constitutes a power backup type non-volatile memory.

Read-only memory (ROM) 108 is a memory that stores programs and various constants.
0 reads data from ROM 108 via bus 150.

The timer 109 is a circuit that generates clock pulses and measures elapsed time, and outputs a clock signal to cpuioo and a time interrupt signal to the interrupt control unit 102.

The output circuit 110 is composed of a latch, a down counter, a power transistor, etc., and generates a pulse signal with a time width corresponding to the fuel injection amount based on the data representing the fuel injection amount calculated by the CPU 100, and sends this pulse signal to the fuel injection valve. 1
5.

Like the circuit 110, the output circuit 112 includes a latch, a down counter, a power transistor, etc., and controls the idle rotation calculated by the CPU. A pulse signal with a duty ratio suitable for the control amount is generated based on the data representing ff1NjX, and this pulse signal is applied to the coil 52 of the electromagnetic valve 51.

The output circuit 113 consists of a latch, a down counter, a power transistor, etc., like the output circuit ff6110.
An ignition timing signal corresponding to the control amount is created based on the ignition time data calculated by the CPU 100, and this timing signal is sent to the igniter section in the ignition device 26.

Next, the operation of the above configuration will be explained. In this example, C
P[Jloo is designed for high-speed processing, and the CPU 100 calculates ignition timing, fuel injection amount, and idle speed control amount in the main routine as shown in Figure 3 according to the program stored in ROM 1.08. The computer is configured to perform operations. Calculation processing for specific parameters such as engine speed, vehicle speed, and predetermined time timer is executed in a separate subroutine by interruption. Of course, the various operations mentioned above can be separated from the main routine.
The method of the present invention can be implemented without any problem even if the reading of engine parameters and the like are performed in the main routine, and various calculations are executed each time by interrupt processing.

Now, by turning on the kill switch 610, the CPU to (
1 is activated, and thereafter each calculation routine is executed in order. Here, the idle rotation speed control amount calculation routine will first be explained using FIG. 4. First, the process starts in step 200, and in the next step 201, human input signals necessary for control are read. That is, the cooling water temperature signal T I
- [W, air conditioner signal A/C, torque converter signal NSS,
Starter signal STA, temperature function map F(t) shown in FIG. Load. However, when it is determined that the starter is on based on the starter signal STA, the previous control 1Di-1 is not appropriate, so the temperature function map F (t
), calculate and use this. In step 202, the temperature function map F (t) is used to obtain a reference control amount adjustment value Dmino as a function of water temperature.

In step 203, the target rotational speed (NF) is calculated according to various operation modes. For example, engine cooling water temperature data, torque converter signal is 22-toral (N) is drive (D
) Depending on whether the range or the air conditioner signal is on or off, for example, as shown in FIG. 5(b), a target rotation speed is calculated according to each operating condition.

Next, proceed to step 204, but here step 202
It is determined whether the idle reference correction amount Δ[)H stored in the nonvolatile memory read in is within a normal range. In other words, as in this embodiment, the key switch 61
The value of ΔD11 stored in the nonvolatile memory 106 to which the battery 60 is directly connected without passing through the battery is
Determine whether the battery terminal has been disconnected or whether the value is abnormal due to other circumstances.

If it is determined in step 204 that ΔN)H is an abnormal value, the process proceeds to step 205, where the appropriate fixed correction amount ΔDIIO stored in the ROM 10B is determined as ΔN)II.
, perform initial settings, and proceed to step 210. If the idle reference correction amount Δ1)+1 is within the normal range at step 204, the process proceeds to step 206.

In step 206, it is determined whether the operating conditions are in a stable idle state, for example, the air conditioner signal and torque converter signal have not changed from the previous time, and the cooling water temperature is above the set temperature and the engine has been warmed up sufficiently. , the previous engine rotation speed (Ni −1) and the current engine rotation speed (
Check that the deviation of Ni) is smaller than the set value.

When all of the above conditions are met, it is determined that the engine is in a stable idle state, and the process proceeds to step 207. If the above conditions are not satisfied, the process proceeds to step 210.

In step 207, the stability condition in step 206 is determined under what operating conditions (whether the torque converter signal is in N range or D range,
Depending on whether the air conditioner signal is on or off)
Use the previous control '411ffiDi-1 to create a control corresponding to the condition where the torque converter signal is in the N range and the air conditioner signal is off.
Calculate t8WDbee1.

In step 20, the control amount Di obtained in step 207
-1 is the idle reference control amount [)re, and step 20
The reference control lower limit value Drnin obtained in step 2.

The correction amount Δ[)II is corrected so that the difference between the two values becomes a constant value ΔH1, and the correction amount Δ[)II is stored in the RAM 106. That is, ΔD' −
The calculation DrD-Dmino-ΔN1 is performed.

In step 210, the correction amount ΔpH stored in the RAM 106 is read out, and this value is used for the reference operating condition (
Control amount (duty ratio) upper limit value Dmax, lower limit value Dm when the torque converter signal is in N range and the air conditioner signal is off)
Calculate in. That is, Dmin=Dmino+ΔD
', Dmax-Dmin+ΔH2 is calculated. (
Note that ΔN2 is a constant value) Next, the process proceeds to step 211, where the upper limit value Dmax and lower limit value Dm of the control amount are determined depending on the operating conditions (whether the torque converter signal is in the N range or D range, and whether the air conditioner signal is on or off).
Correct in.

In step 212, the engine rotation speed N read in step 201 and the target rotation speed N obtained in step 203 are used.
The deviation ΔN from F (ΔN=Ni−NF) is calculated.

Next, the process proceeds to step 213, where the control correction value for the absolute value of the deviation ΔN as shown in FIG. 5(d) is determined.
The previous control 1Di-1 read in step 201 is corrected based on the positive/negative of , and is set as control ff1D. That is, when ΔN>O, DmDi-1-ΔD, and when ΔN≦00, D-Di-1+ΔN.

Next, proceeding to step 214, when the operating conditions change (when the torque converter signal or air conditioner signal is different from the previous time and this time),
In order to reduce overshoot or undershoot of the engine speed due to changes in operating conditions, the control amount determined in step 213 is prospectively corrected in accordance with the changes in operating conditions.

In step 215, the control amount obtained in step 214 is equal to the lower limit value Dmax of the control amount obtained in step 211.
It is determined whether or not it is within the range of and Dmin, and if it is within the range, the process advances to step 217.

In step 211, the control 11D is set to Dmax if the control fiD is greater than the upper limit Dmax, and to Dmin if it is smaller than the lower limit Dmin.

Controlled by step 217? RA with affiD as Di-1
The control amount is stored in M106, and the control amount is outputted to the output circuit 112 in step 218, and this calculation routine is ended.

The control scale indicating the duty ratio calculated by the CPU 100 is output to the output circuit 112 and latched as shown in FIG. It is converted into a signal and output to the solenoid valve 51. Thus, the amount of auxiliary air that bypasses the throttle valve 16 is controlled so that the idle rotational speed of the engine becomes the target rotational speed.

After controlling the auxiliary air amount in this manner, the engine parameter reading routine reads the intake air amount (Q), cooling water temperature, etc. through the input port 103, and then the idle ignition timing correction calculation routine is executed again.

Fig. 6 shows the calculation routine.Ignition timing calculation starts at step 300, and in the next step 301, input information necessary for control among the information processed in the engine parameter reading routine etc. is read from the RAM. put out. That is, the engine rotation speed N, intake air amount signal Q, cooling water temperature signal THW, starter signal STA, vehicle speed signal SPD, air conditioner signal A/C, throttle switch signal, etc. are output one after another. At step 302, the basic advance angle θ8. . is the basic advance angle map θ which is mainly a function of (Q/Ni, Ni)
,! This is calculated and used from E (θ/Nt, Ni). In this embodiment, the engine rotational speed signal N is generated every 30° (crank angle CA), and Ni is the average rotational speed during a crank angle of 120°. Furthermore, the basic advance angle map technology is well known and will not be described in detail.

In step 303, an ignition advance correction calculation is performed according to various engine parameters to obtain an advance angle correction amount Qa. For example, warm-up advance angle correction and fixed advance angle correction are applicable, and these correction amounts are stored in advance in a correction map and are read out and used each time.

Then, in the next steps 304 to 306, it is determined whether or not the idle ignition timing control should be further implemented. That is, in step 304, it is determined that the cooling water temperature is equal to or higher than the set temperature and that the engine has been sufficiently warmed up;
In step 5, it is confirmed that the throttle valve 16 is fully closed or almost fully closed and the engine is in an idling state, and in step 305, it is confirmed that the vehicle speed is less than, for example, 2 knl/)l and the vehicle is stopped or almost stopped. .

If any one of the above conditions is not met, the process proceeds to step 307; on the other hand, if all of the above conditions are met, it is determined that the engine is in an idle state and the process proceeds to step 310. Therefore, when the engine is not in an idling state, in step 307, the idling advance angle correction amount θ1. c=0, and in step 308, the previously determined basic advance angle values θ, sE, various advance angle correction amounts θα, and idle special advance angle correction amounts θ1. c (in this case, θ+5c=0) is added to obtain the advance angle value θ. In step 309, this value θ is output to the output circuit 113 as an ignition timing signal and latched. Then, the output timing of the output circuit 113 is controlled according to an output timing command from the CPU 100,
Ignition is performed using the ignition device 26 at the advance angle value θ.

On the other hand, when the engine is in an idle state, the process proceeds from step 306 to step 310. In step 310, the average value N of the engine rotational speed N during the latest crank angle 120@ obtained in step 302 is successively calculated, and the latest target rotation obtained by the idle rotational speed control amount calculation routine shown in FIG. Read the speed N. Then, the deviation ΔN (ΔN=N, -Ni) between the two is calculated. Step 311
Now, depending on the calculated deviation ΔN, the idling advance angle correction amount θr is determined from the (ΔN) map shown in the characteristic line ■ or ■ in Fig. 7.
Find sc. In addition, both the characteristic lines ■ and ■ in FIG. 7 show that when the deviation (ΔN) is positive (lower rotation side), the correction amount θ18. is set asymmetrically to increase the rotation speed, thereby preventing a drop in rotation with good response.

Now, in step 311, the idle advance angle correction amount θI3c
Once obtained, the advance angle value θ (θ=θll5E+θα+θ15c) is calculated in step 308 in the same manner as described above, and in step 309, the advance angle value θ is outputted to the output circuit 113 as an ignition timing signal. No Jōgi (Change in content) Then, the advance angle value θ is set at a predetermined timing according to an output timing command from the CPU 100.
The ignition operation is performed.

As described above, when the ignition timing calculation routine is completed, the fuel injection amount calculation routine is subsequently executed, but this calculation routine calculates the basic injection time from the engine rotational speed N and intake air MQ, and then This is a known method that performs correction according to engine parameters such as cooling water temperature and intake air temperature, and will not be described in detail.

As described above, each calculation routine is processed at high speed in the main routine, and the calculated value is output to each actuator and driven at a predetermined timing determined by the CPU. As a result, when the engine is in a predetermined idle state, both the auxiliary air amount and the ignition timing are skillfully manipulated to adjust the engine rotational speed to the target rotational speed N. Therefore, when the engine rotational speed fluctuates sharply, the ignition timing can be effectively operated with quick response, and the rotational speed fluctuation can be effectively suppressed.

FIGS. 8 and 9 show experimental results for explaining the effects of using the method of the present invention. Figure 8 shows the effect of improving idle stability. Figure (A) shows the fluctuation state of engine speed when only adjusting the auxiliary air amount, and Figure (B) shows the same condition. 7 shows the fluctuation state of the engine rotational speed and the advance angle correction amount θllIc when the adjustment of the auxiliary air amount and the advance angle correction (using the (ΔN) map of the characteristic line ■ in FIG. 7) are used together. As is clear from this figure, the rotational speed fluctuation (deviation) ΔN is suppressed to approximately half or less.

In addition, Figure 9 shows the effect of improving transient response during idling, and Figure (A) shows the effect of improving the transient response during idling. Figure (B) shows the engine rotation speed when adjusting the amount of auxiliary air and adjusting the advance angle (using the (ΔN) map of characteristic line ■ in Figure 7) under the same conditions. The fluctuation state and the advance angle correction amount θISC are shown. As is clear from this figure, the rotation drop (or rotation increase) when the engine load is applied (or when the load is released) is suppressed to about half.

In the above embodiment, as a method of correcting the idle advance angle, the advance angle correction amount θ0 is calculated using a (ΔN) map obtained by determining the deviation ΔN between the target rotational speed N and the latest engine rotational speed Ni.
5. However, in the calculation routine of FIG. 6, step 41 shown in part (1) is substituted for steps 310 and 311.
0.411, and the (ΔN) map shown in FIG. 1O may be used instead of FIG. 7.

In other words, instead of the previous deviation ΔN, the deviation (change amount) dN=Ni-1-Ni between the engine rotation speed Ni-1 obtained last time and the latest engine rotation speed Ni is calculated, and this deviation dN
In accordance with this, the advance angle correction amount θIsc is determined using a (dN) map as shown in FIG. Using this method is particularly effective when the engine speed changes suddenly, making it possible to effectively suppress rotational fluctuations.

In addition, the characteristic line ◎ in Figure 10 indicates that the advance angle correction at idle is performed even if the deviation dN swings in either a positive or negative direction.
On the other hand, the characteristic line (3) is a map in which the idle acceleration angle correction is performed only when the deviation dN swings positively. Both characteristic lines ◎ and ■ are set asymmetrically so that when the deviation dN is positive (lower rotation side), the correction amount is larger than when it is negative (lower rotation side).

As described above, according to the present invention, during engine idling operation, in addition to controlling the air-fuel mixture amount to the engine, the ignition timing is corrected according to the degree of decrease or increase in engine rotation speed, so We can respond with good response to
This has an excellent effect in that the drop in rotation can be made very small even when there is a sudden load change during idling (for example, when the power steering is turned off). Moreover,
Since the ignition timing correction amount is increased on the side where the engine speed is low, where engine stalls tend to occur, there is also the effect that optimal control can be performed for engine speed fluctuations.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is a block diagram of the computer shown in FIG. 1, FIG. 3 is a flowchart showing the overall flow of the computer, and FIGS. 4 and 5. Idle speed control '411! Flowcharts and characteristic diagrams to explain the calculation routine, Figures 6 and 7 are flowcharts and characteristic diagrams to explain the ignition timing calculation routine, and Figures 8 and 9 are experimental data showing an example of idle rotation speed control. , FIG. 10 is a characteristic diagram for explaining another example of the ignition timing calculation routine. 10... Engine, ia, 19... Air conduit, 20
... Microcomputer, 26 ... Ignition device, 3
0...Air control valve. Representative Patent Attorney Takashi Okabe Figure 2 Figure 3 Figure 4 (a) (b) (c) ((i) ΔN
(rpm+ Fig. 7 drawing sexual punishment (no change in content) ヱ'' Hill degree 11 虱- (A) (B) Fig. 8 rihen d, main Fig. 9 dN (rpm) Fig. 10 procedure Amendment (c) February 5, 1986

Claims (1)

[Claims] The engine rotation speed is detected during engine idling operation, and the amount of air-fuel mixture supplied to the engine is controlled so that the engine rotation speed matches a target rotation speed set in advance according to engine operating conditions. The ignition timing is corrected according to the degree of decrease or increase in engine rotation speed, and the amount of correction is made asymmetrical so that when the engine rotation speed is on the decrease side, it is larger than when it is on the increase side. Characteristic engine speed control method.