JPS608468A - Method of controlling ignition timing in internal- combustion engine - Google Patents

Abstract

PURPOSE:To prevent output from reduction by increasing delay of ignition timing under the abrupt acceleration condition in which knocking occurs often and decreasing the delay after said condition is changed over to the steady one in which knocking does not often occur. CONSTITUTION:The opening of a throttle valve 6 is detected by a throttle sensor 22 which generates a signal for judging abrupt acceleration. Upon detecting the abrupt acceleration is obtained abrupt acceleration delay in CPU40. The abrupt acceleration delay is set to a certain angle in detecting the abrupt acceleration and then gradually decreased. Thus, knocking is prevented while preventing the output from reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control method for an internal combustion engine, and particularly to an ignition timing control method during sudden engine acceleration. −'− Conventionally, the basic ignition advance angle is determined according to the engine load (intake air amount and intake pipe pressure per engine rotation) and engine speed, and the knocking state and engine cold period are controlled. It has been known. This amount of intake air is detected by an air flow meter provided downstream of the air cleaner, and the intake pipe pressure is detected by a pressure sensor provided downstream of the throttle valve. In an internal combustion engine in which the ignition timing is controlled by such a method, when the throttle valve is suddenly opened and the throttle valve is suddenly accelerated, the air pressure on the downstream side of the throttle valve is lower than the air pressure on the upstream side of the throttle valve before the throttle valve is suddenly opened. Since the air pressure is the same, more air than the amount of air detected by an air flow meter or the like is instantaneously supplied to the engine combustion chamber.

As a result, the air-fuel ratio becomes lower than the required value, and the actual engine load becomes higher than the detected load, making knocking more likely to occur.

Therefore, in the past, a throttle sensor was attached to the throttle valve to detect sudden acceleration of the engine from the throttle valve's sudden opening state.
When the engine suddenly accelerates, the engine is immediately retarded by a certain amount. However, with this method, even if knocking does not actually occur, the output is significantly reduced and the acceleration feeling deteriorates.

Therefore, when sudden acceleration is detected, the sudden acceleration retardation amount that is set to a predetermined value is held until knocking occurs, and when knocking occurs, the ignition timing is retarded by an amount equivalent to this sudden acceleration retardation amount. It is proposed that

However, if knocking does not occur during sudden acceleration and knocking occurs after the operating conditions have become steady, the amount of sudden acceleration retardation that was maintained will be affected, and even though knocking does not occur frequently, the The problem arises that the ignition timing is retarded and the output decreases.

The present invention was made in order to solve the above problem, and the amount of retardation is increased under conditions of rapid acceleration where knocking occurs frequently, and the amount of retardation is increased after steady conditions where knocking does not occur frequently. An object of the present invention is to provide an ignition timing control method for an internal combustion engine that prevents a decrease in output by reducing the ignition timing of the engine.

In order to achieve the above object, the present invention is configured such that when rapid engine acceleration is detected, the ratio is set to a predetermined value and is reduced by a first ratio in the ratio at which knocking occurs, and the ratio is set to a predetermined value. The ignition timing is controlled based on the value obtained by subtracting the sudden acceleration retardation amount from the predetermined basic ignition advance angle when knocking occurs, taking into account the sudden acceleration retardation amount that is reduced at a second larger rate. It is composed of

In the above configuration of the present invention, the sudden acceleration retardation amount is reduced at a second rate after a predetermined time has elapsed after knocking has occurred, and the sudden acceleration retardation amount is reduced after a predetermined time has elapsed after sudden acceleration has been detected. We can find a way to set the value to 0. In addition, when controlling the ignition timing, a correction delay is used that retards the ignition timing when knocking occurs and advances the ignition timing when no knocking occurs from the value obtained by subtracting the sudden acceleration retardation amount from the basic ignition advance angle. A mode of controlling by subtracting the angle amount can be adopted.

According to the above configuration of the present invention, under operating conditions where knocking occurs frequently during sudden acceleration, the time from sudden acceleration to the occurrence of knocking is short, so the amount of decrease in the sudden acceleration retardation amount is small, and the steady state where knocking does not occur frequently from sudden acceleration is small. As the driving conditions become more favorable, the amount of decrease in the rapid acceleration retardation amount becomes larger, so that it is possible to perform retardation control according to the driving conditions, and to prevent a decrease in output.

Next, an example of an internal combustion engine to which the present invention is applied will be explained with reference to FIG. This engine is controlled by an electronic control circuit such as a microcomputer, and as shown in the figure, is equipped with an air flow meter 2 as an intake air amount sensor downstream of an air cleaner (not shown). The air flow meter 2 is rotatably provided in the damping chamber. *Compensation motion plate 2A
and a potentiometer 2B that detects 1M& of the convention plate 2A. Therefore, the amount of intake air is detected based on the voltage output from the potentiometer 2B. In addition, an intake air temperature sensor 4 that detects the temperature of intake air is installed near the air flow meter 2.
is provided.

A throttle valve 6 is arranged downstream of the air flow meter 2, and a throttle sensor 22 for detecting sudden acceleration of the engine is attached to the throttle valve 6.
A surge tank 8 is provided downstream. An intake manifold 10 is connected to the surge tank 8, and a fuel injection valve 12 is disposed protruding into the intake manifold 10. The intake manifold 10 is connected to a combustion chamber 14A of the engine body 14, and the combustion chamber 14A of the engine is connected via an exhaust manifold 16 to a catalytic converter (not shown) filled with a three-way catalyst. The engine body 14 is provided with a knocking sensor 18 that is composed of a microphone or the like and detects engine vibrations caused by combustion. Note that 20 is a spark plug, and 24 is a coolant temperature sensor that detects the engine coolant temperature.

The spark plug 2° attached to the engine body 14 is connected to a distributor 26, and the distributor 26 is connected to an igniter 28. The distributor 26 is provided with a cylinder discrimination sensor 30 and an engine rotation angle sensor 32, each of which includes a pickup fixed to the distributor housing and a signal rotor fixed to the distributor shaft. This cylinder discrimination sensor 30 outputs a cylinder discrimination signal to an electronic control circuit 34 composed of a microcomputer or the like every 720 degrees of the crank angle, for example, and the engine rotation angle sensor 32 outputs a cylinder discrimination signal based on the crank angle every 30 degrees of the crank angle. A position signal is output to the electronic control circuit 34.

As shown in FIG. 2, the throttle sensor 22 includes an abbreviated rotating piece 80 whose base end is connected to the rotating shaft 6a of the throttle valve 6. One end of a first contact 82 is fixed to the base end of the rotating piece 800 so as to extend in the direction of the distal end of the rotating piece 80 and not to come into contact with the distal end of the rotating piece 80 . Furthermore, one end of a second contact 86 is fixed to the tip of the rotating piece 80 via an insulating material 84 so as to be parallel to the first contact 82 . This second contact 8
6 is grounded. A comb-shaped first VL pole 88 and a comb-shaped second electrode 90 are arranged to face the first contact 82 with the teeth of the other electrode interposed between the teeth of the electrodes. has been done. One ends of the first electrode 88 and the second electrode 90 are connected to a power source via a resistor 92 and a resistor 94, respectively, and are also connected to the electronic control circuit 34, respectively.

In this throttle sensor, when the throttle valve 6 is rotated in the 4 direction (in the direction of the arrow in the figure), the rotating piece 80 rotates to connect the first contact 82 and the second contact. The tip of the first contact 82 is in contact with the first contact 86.
Since the electrode 88 and the second electrode 90 are alternately contacted and grounded, a pulse signal having a waveform as shown in FIG. 3 is output.

Note that when the throttle valve is rotated in the closing direction, the first contact 82 and the second contact 86 are rotated in a non-contact state, so that no pulse signal is output.

As shown in FIG. 4, the electronic control circuit 34 includes a random access memory (RAM) 36, a read-only memory (ROM) 38, a central processing unit (CPU) 40,
Clock (CLOCR) 41, first input/output port 42
, a second input/output port 44, a first output port 46, and a second output port 48, and the RAM 36
, ROM 38, CPU 40, CLOCR 41, first input/output port 42, second input/output port 44, first output port 46, and second output port 48 are connected to a bus 50 such as a data bus or a control bus. It is connected.

The first input/output port 42 includes a buffer (not shown),
Multiplexer 54, analog-digital (A/D)
The air flow meter 2, cooling water temperature sensor 24, intake air temperature sensor 4, etc. are connected via the converter 56. This multiplexer 54 and A/D converter 56
It is controlled by a control signal outputted from the input/output port 42 of.

A first electrode 88 and a second electrode 90 of the throttle sensor 22 are connected to the second input/output port 44, and
A cylinder discrimination sensor 30 and an engine rotation angle sensor 32 are connected via a waveform shaping circuit 64. Also, the second
The knocking sensor 18 is connected to the input/output port 44 of the engine via a bandpass filter 60, a peak hold circuit 61, a channel switching circuit 66, and an A/D converter 68. This bandpass filter 60 is an integrating circuit 6
It is connected to the channel switching circuit 66 via No. 3.

This channel switching circuit 66 is connected to either the output of the peak hold circuit 61 or the output of the integration circuit 63.
A control signal for inputting to the /D converter 68 is inputted from the second input/output port 44 , and a reset signal and a gate signal are inputted to the peak hold circuit 61 from the second input/output port 44 . It has been entered.

Further, the first output port 46 is connected to the igniter 28 via a drive circuit 70, and the second output port 48 is connected to the fuel injection valve 12 via a drive circuit 72.

The ROM 38 of the electronic control circuit 34 stores in advance a basic ignition advance angle map and control program determined based on the intake air amount per engine revolution and engine speed, and the air flow meter 2 and engine speed. Angle sensor 3
The basic ignition advance angle is read based on the signal input from the cooling water temperature sensor 24 and the intake air temperature sensor 4.
The basic ignition advance angle is corrected and the igniter 28 and the like are controlled by various signals including signals from the engine.

Next, an embodiment in which the present invention is applied to the engine as described above will be described in detail. In the detailed explanation of the present invention, in order to avoid complication, the explanation will be made using the most convenient numerical values, but the present invention is not limited to these numerical values, and the present invention is not limited to these numerical values. value is selected.

FIGS. 5 to 8 show processing routines in the first embodiment of the present invention. In this embodiment, the sudden acceleration retardation amount θAC is decreased at a first rate of 0.01° CA/4 m5ec from sudden acceleration to the occurrence of knocking, and then immediately after the occurrence of knocking, it is reduced to 0.
Rapid acceleration retardation amount θA at the second rate of 1°CA/4m5ec
In addition to reducing C, the ignition timing is controlled based on the value obtained by subtracting the sum of the corrected retard amount θ and the seventh rapid acceleration angle adjustment cover θAC from the basic ignition advance angle θBAsE.

FIG. 5 shows the main routine of this embodiment. In step 95, the intake air amount per engine revolution, that is, the engine load Q/N is 0.4 L/r e v.

It is determined whether the engine operating conditions are within the knocking control region by determining whether or not the engine rotational speed N is equal to or less than or equal to or less than or equal to or less than or equal to to decide. Load Q/N is 0.4
t/r, tv, and the engine speed N is 8
If it exceeds 00γ, pom, it is determined that the engine operating conditions have entered the knocking control region, and the process proceeds to step 9.
8, the knocking control flag floor A is set. On the other hand, in other cases, the engine operating conditions do not fall within the knocking control region, so the knocking control flag FKCA is reset in step 97.

Figure 6 shows a routine for determining sudden acceleration and setting the sudden acceleration retardation amount θAC, which is interrupted by the falling edge of the pulse signal output from the first and second electrodes of the throttle sensor. . In step 100, it is determined whether or not there is an interrupt caused by the falling edge of the output signal of the first electrode. If the interruption is caused by the first electrode, it is determined in step 101 whether or not the flag FeO value is 0, and if the value of the flag Fe is If O, the flag FgO value is inverted in step 103. In addition, when the interruption is not caused by the first electrode, in step 102, the 7-lag FgO
It is determined whether the value is 1 or not, and if the value of the flag Fe is 1, the value of the 7-lag Ft is inverted in step 103. On the other hand, when the value of 7 lag Fe is 1 in step 101 and step 1
If the value of the 7-lag F6 is 0 at 02, the process advances to step 106.

In step 104, the count value TAC of the acceleration timer, which is incremented in step 117 of FIG.
m(8)) or less is determined to determine whether or not there is sudden acceleration. This acceleration timer counts the time between the fall of the signal output from the first electrode and the fall of the signal output from the second electrode, and the smaller the count value TAC, the faster the This indicates acceleration. Count value T
When AC is 25 or less, it is determined that there is a sudden acceleration, and in step 105, the value of the sudden acceleration retardation amount θAC is set to 8°CA and R is performed.
It is stored in a predetermined area of AM and the count value TAC is cleared in step 106. When the count value TAc exceeds 25, the count value TAC is changed directly to step 106.
Clear.

FIG. 7 shows a routine for calculating the corrected ignition retard amount θ and the executed ignition advance angle θ, t.
Interrupted by CABTDC. In step 107, it is determined whether the knocking control flag F'xcA is set, and it is determined whether or not the knocking control region is reached. If it is a knocking control area, step 109
and the predetermined crank angle range of the explosion stroke of each cylinder (for example,
100 CAATDC to 50° CAATDC), the band pass filter 60 and the peak hold circuit 61
, the peak value a of the electric signal in a predetermined frequency range (7 to 8 KHz) inputted via the channel switching circuit 66 and the A/D converter 68, and the explosion stroke of each cylinder,
Bandpass filter 60. It is determined whether υ knocking has occurred by comparing the background level b input through the integrating circuit 63, the channel switching circuit 66, and the A/D converter 68 with a determination level kb obtained by multiplying the background level b by a constant k. to decide.

If it is determined that knocking has occurred, the knocking flag Fx is set in step 111, and the value of the corrected retard amount θ is increased by 0.4° CA in step 112. On the other hand, when it is determined that knocking does not occur, the value of the corrected retard amount θ is set to 0.0 in step 110.
Reduce by 8°CA. In the next step 113, it is determined whether or not the knocking flag FK is set, and if it is set, step 114 and step 116
, the basic ignition advance angle θBASE read from the ROM
Then, the effective ignition advance angle θ is decreased by subtracting the sum of the sudden acceleration retard amount θAC and the corrected retard amount θ. On the other hand, if the knocking flag FK is not set, the value obtained by subtracting the corrected retard amount θK from the basic ignition advance angle θBAsE is set as the effective ignition advance angle θL2 in steps 115 and 116.

When it is determined in step 107 that the engine is not in the knocking control region, the value of the corrected retard amount θ is set to 0 in step 108, and the effective ignition advance angle θL2 is calculated in steps 115 and 116.

FIG. 8 shows an interrupt routine every 4 m5ec that increments the count value TAC, which is a reference for sudden acceleration determination, and decreases the corrected retardation amount θAC. First, in step 117, the count value TAC is incremented by 1, and in step 118, it is determined whether the count value TAC is 30 or less. If the count value TAC exceeds 30, step
19, the count value TAC is set to 30. Step 120
Then, it is determined whether or not the knocking flag Fx is set, that is, whether or not the occurrence of knocking is detected. If the flag Fx is reset, the sudden acceleration retardation amount θAC is decreased by 0.01°α in step 122. Let flag FX
is set, the sudden acceleration retardation amount θ is determined in step 121.
Decrease AC by 0.1°CA. Then, in Step 12, it is determined whether the sudden acceleration retardation amount θAC is 0 or more, and if the sudden acceleration retardation amount is less than 0, the sudden acceleration retardation amount is set to 0 in Step 124, and in Step 125 7 lag FX
Reset. Note that if the sudden acceleration retardation amount θAC is 0 or more, the process directly advances to the next routine.

As a result of the above, the sudden acceleration retardation amount θAC is set to a predetermined value at the time of sudden acceleration and is decreased at a first rate until knocking occurs, and is reduced at a second rate that is larger than the rate of the second section 1 at which knocking occurs. is reduced by Then, when knocking occurs, the sum of the correction retard amount and the sudden acceleration retard amount is subtracted from the basic ignition advance angle, and is further corrected according to the engine coolant temperature, etc., and ignition is performed with the corrected value. The igniter is controlled to turn on and off.

Rapid acceleration retardation lid θAC when controlled as above
Figure 9 shows the changes in . The broken line in the figure shows the calculation result.

In the above embodiment, when knocking occurs during sudden acceleration, the retardation is retarded by the sum of the correction retardation amount and the sudden acceleration retardation amount, so that the retardation control is performed according to the engine operating conditions before sudden acceleration. You can get the effect that you can do it. In other words, the amount of correction retardation is increased under driving conditions where knocking occurs frequently before sudden acceleration, so when knocking occurs during sudden acceleration, the angle will be retarded to a greater extent than under driving conditions where knocking does not occur before sudden acceleration. .

Next, regarding the second embodiment of the present invention, FIGS.
This will be explained with reference to FIG. In this embodiment, the idle acceleration retardation amount is set to 0.01 for 300 m5ec after sudden acceleration is detected.
300 by decreasing at the rate of °CA/4 m5ec
m5et: The sudden acceleration retardation amount is set to 0 when it has elapsed, and when knocking occurs, 01°CA 74 m5e
The rapid acceleration retardation amount θAC is reduced by a ratio of c. Note that FIG. 10 in this embodiment corresponds to FIG. 6 in the first embodiment, and FIG. 11 corresponds to FIG. 8, so the same parts are given the same reference numerals and explanations will be omitted. Further, the other routines of this embodiment are the same as those of the first embodiment, so their explanation will be omitted.

In FIG. 1θ, after the sudden acceleration retardation amount θAC is set to 8° CA in step 105, in step 126, 00
The count value TACt of the timer that reduces the amount of sudden acceleration/retardation at a rate of 1° CA/4 m5ec is set to 75 (= 3
00 m5ec). In FIG. 11, when it is determined in step 120 that the knocking flag FK has been reset, the count value T is determined in step 127.
Decrement ACt by 1. In the next step 128, it is determined whether the count value TACt is less than or equal to θ, and if it is less than 0, the count value TACt is set to O in step 130. On the other hand, if the count value TAct exceeds 0, the rapid acceleration retardation amount θAC is set to 0.01°C in step 122.
A decrease. In addition, after decreasing the sudden acceleration retardation amount θAC by 0.16 CA in step 12゛1, in step 129
Let the count value TAct be O.

As a result of the above, the idle acceleration retard amount is reduced at the first rate for a predetermined time after sudden acceleration is detected, and after knocking occurs, the sudden acceleration retard amount is reduced at the second rate, and After a period of time has elapsed, the rapid acceleration retardation amount is set to O.

According to the second embodiment, the sudden acceleration retardation amount is reduced to 0 after a predetermined time.
Because of this, it is possible to obtain the effect that the output rises quickly.

Next, a third embodiment of the present invention will be described based on FIG. 12. Figure 12 shows the 4 m
This shows an interrupt routine for each st<, and corresponds to the routine of FIG. 8 in the first embodiment, so the same parts are given the same reference numerals and the explanation will be omitted. Further, other routines in the unimplemented embodiment are the same as those in the first embodiment, and therefore their explanations will be omitted. In this example, 0 is maintained until 100 m5ec elapses after knocking occurs from sudden acceleration.
．． The rapid acceleration/retardation amount is decreased at a rate of 0.1°CA/4 m(8), and then the rapid acceleration/retardation amount is decreased at a rate of 0.1°CA/4m5ec.

If it is determined in step 120 that the knocking flag FK is set, in step 131 the count value TA of the timer indicating the time from the occurrence of knocking is set.
Ct1 is incremented by 1, and in step 132 it is determined whether the count value TAct1 is equal to or greater than 25 (=100 m5ec). Count value TActt is 25
In the above case, in order to prevent overflow, the count value TAct1 is set to 25 in step 133, and step 1
21, the sudden acceleration retardation amount θAC is decreased by 0.1°CA.

On the other hand, when the count value TActs is less than 25, the rapid acceleration retardation amount θAC is decreased by 0.01°CA in step 122. Further, when it is determined in step 120 that the knocking flag FK has been reset, in step 13
After setting the count value TActl to O in step 4, step 12
2, the sudden acceleration retardation amount θAC is decreased by 0.01°CA.

As a result of the above, the sudden acceleration retardation amount is set at the time of sudden acceleration, and the sudden acceleration retardation amount is decreased at the first rate until a predetermined time elapses after the occurrence of knocking, and the sudden acceleration retardation amount is reduced at the ratio of Apprentice 2. reduced.

According to the above-mentioned embodiment, since the rapid acceleration/retardation amount with a small decreasing rate is maintained for a certain period of time after the occurrence of knocking, the period during which the sudden acceleration/retardation amount is effective can be adjusted by appropriately setting the count value TActl. The effect is that it can be easily adapted.

FIG. 13 shows changes in the amount of sudden acceleration and retardation in this embodiment. Note that the broken line indicates the calculated value.

In addition, although the engine that determines the basic ignition advance angle according to the intake air amount per engine rotation and the engine rotation speed has been described above, the present invention sets the basic ignition advance angle according to the intake pipe pressure and the engine rotation speed. It is also possible to apply it to the specified engine.

In this case, the intake pipe pressure is detected by a pressure sensor provided downstream of the throttle valve.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of an engine to which the present invention is applied, Fig. 2 is a circuit diagram showing details of a throttle sensor, Fig. 3 is a diagram showing a signal waveform output from the throttle sensor, and Fig. 4 is a diagram showing an example of an engine to which the present invention is applied. The figure is a block diagram showing the details of the electronic control circuit of Fig. 1, Fig. 5 is a flowchart showing the main routine in the first embodiment of the present invention, and Fig. 6 is a flowchart showing the main routine in the first embodiment of the invention. A flowchart showing the interrupt routine, FIG. 7 is a 90° CABTD in the first embodiment.
A flowchart showing the interrupt routine in C, FIG. 8 is a flowchart showing the interrupt routine every 4 m5ec of the first embodiment,
FIG. 9 is a diagram showing changes in the amount of sudden acceleration/retardation in the first embodiment, FIG. 10 is a flowchart showing an interrupt routine based on the signal of the throttle sensor in the second embodiment of the present invention,
FIG. 11 is a flow chart showing the interrupt routine for every 4 m5ec in the second embodiment, FIG. 12 is a flow chart showing the interrupt routine for every 4 m5ec in the third embodiment of the present invention, and FIG. 13 is a flow chart showing the interrupt routine for every 4 m5ec in the third embodiment of the present invention. FIG. 3 is a diagram showing changes in the amount of sudden acceleration/retardation in the example of FIG. 6... Throttle valve, 18... Knocking sensor, 22... Throttle sensor, 34... Electronic control circuit. Agent Tatsuyuki Unuma (ti 17mon Figure 10 Figure 11

Claims (1)

[Claims] (1) When sudden engine acceleration is detected, it is set to a predetermined value and is decreased at a first rate until knocking occurs, and after knocking occurs, it is decreased at a second rate that is larger than the first rate. An ignition timing control method for an internal combustion engine, in which the ignition timing is controlled based on a value obtained by subtracting the sudden acceleration retardation amount from a predetermined basic ignition advance angle when knocking occurs.