JPH0571793B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ignition timing control device for an internal combustion engine,
In particular, the present invention relates to an ignition timing control device for an internal combustion engine suitable for controlling the ignition timing of the engine to be retarded by a predetermined amount during sudden engine acceleration to suppress the occurrence of knocking during sudden acceleration.

[Prior Art] In a vehicle engine such as an automobile, when the engine's ignition timing is retarded during rapid engine acceleration, the pressure between the throttle valve and the engine combustion chamber becomes lower than the pressure between the air flow meter and the throttle valve. Air that exceeds the amount of intake air measured by the airflow meter is momentarily supplied to the engine. For this reason, it is known that the air-fuel ratio becomes leaner than the required value, and the actual engine load becomes higher than the measured load expressed by the ratio of the intake air amount to the engine speed, making knocking more likely to occur.

Therefore, conventionally, when the engine suddenly accelerates, the ignition timing of the engine is retarded by a predetermined amount. However, with this method, the ignition timing is retarded when the engine suddenly accelerates even if no knocking has actually occurred, resulting in an unnecessary drop in output and a worsening of the acceleration feeling.

Therefore, the applicant of the present application determined the initial value of the retard amount, which is the retard amount for correcting the ignition timing when the engine suddenly accelerates, and which gradually attenuates as time passes, and when the occurrence of knocking is detected, We previously proposed a method for retarding the engine's ignition timing based on the amount of retardation when this knocking occurs (Japanese Patent Application No. 58-5616).
issue). According to this method, the engine's ignition timing is not retarded except when knocking occurs.
It is possible to prevent unnecessary reduction in output or deterioration of acceleration feeling.

[Problem that the invention seeks to solve]

However, in the method previously proposed by the applicant, when knocking occurs only once after setting the initial value as the retard amount, the engine ignition timing is retarded based on the retard amount at the time the knocking occurred. Therefore, it is possible to suppress engine vibration caused by knocking, but when knocking occurs again, the amount of retardation has gradually attenuated, so the engine ignition timing is retarded based on the amount of retardation at this time. Even with angle control, there was a risk that engine vibrations caused by knocking could not be sufficiently suppressed.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to sufficiently suppress the occurrence of knocking during sudden acceleration without causing unnecessary reduction in output or deterioration of acceleration feeling. An object of the present invention is to provide an ignition timing control device for an internal combustion engine that is capable of controlling the ignition timing of an internal combustion engine.

[Means for solving problems]

In order to achieve the above object, the present invention includes a throttle sensor that detects engine vibration, a throttle sensor that detects the opening degree of the throttle valve, and a throttle sensor that monitors the detection outputs of a knock sensor and a throttle sensor. When a sudden acceleration state of the engine is detected by the detection output of the sensor, an initial value of the retard amount that is used to correct the ignition timing and that gradually attenuates over time is set, and this initial value is set. After setting the value, when the occurrence of knocking is detected by the detection output of the knock sensor, the engine ignition timing is retarded based on the amount of retardation at the time of knocking occurrence, and if knocking occurs again after this retard control, this knocking is An ignition timing control device for an internal combustion engine includes a control section that returns the amount of retardation at the time of occurrence to an initial value and retards the ignition timing of the engine based on this initial value.

[Effect]

The control unit that controls the ignition timing of the engine monitors the detection output of the knock sensor and the throttle sensor, and when a sudden acceleration state of the engine is detected by the detection output of the throttle sensor, the retardation amount is set to correct the ignition timing. After setting the initial value, when the occurrence of knocking is detected by the detection output of the knock sensor, the amount of retardation when knocking occurs is set. Based on this, the engine's ignition timing is retarded,
When knocking occurs further after this retard control, the retard amount at the time when the knocking occurs is returned to the initial value, and the ignition timing of the engine is retarded based on this initial value.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the configuration of a preferred embodiment of the present invention. In FIG. 1, an air flow meter 2 as an intake air amount sensor is provided downstream of an air cleaner in an engine intake system. This air flow meter 2 includes a compensation plate 2A rotatably provided within a damping chamber.
and a potentiometer 2B that detects the opening degree of the compensation plate 2A, and is configured to detect the amount of intake air based on the output voltage of the potentiometer 2B.

On the downstream side of the air flow meter 2, an intake temperature sensor 4 for detecting the temperature of intake air, a throttle valve 6, and a surge tank 8 are arranged. An intake manifold 10 is connected to the surge tank 8, and a fuel injection valve 12 is disposed in the intake manifold 10. The intake manifold 10 is a combustion chamber 14 of an engine body 14.
A, and the combustion chamber 14A of the engine is connected to the exhaust manifold 16. or,
A throttle sensor 18 is disposed in the intake system to detect the opening degree of the throttle valve 6, and the engine body 14 includes a knock sensor 22, which includes a spark plug 20, a microphone, etc., and detects engine vibrations caused by combustion. A cooling water temperature sensor 24 is provided to detect the engine cooling water temperature.

The spark plug 20 is connected to a distributor 26 that supplies an ignition signal to the spark plugs of each cylinder, and an igniter 28 is connected to the distributor 26. The distributor 26 includes a cylinder discrimination sensor 30 and an engine rotation angle sensor 32, each of which includes a pick-up fixed to the distributor housing and a signal rotor fixed to the distributor shaft.
is provided. The cylinder discrimination sensor 30 outputs a cylinder discrimination signal, for example, at every crank angle of 720 degrees, and the engine rotation angle sensor 32 outputs a cylinder discrimination signal, for example, at every crank angle of 720 degrees.
It is configured to output a crank angle reference position signal every 30 degrees. And air flow meter 2,
The detection outputs of sensors that detect various operating states of the engine, such as the intake temperature sensor 4, throttle sensor 18, cooling water temperature sensor 24, knock sensor 22, rotation angle sensor 32, and cylinder discrimination sensor 30, are transmitted to the control unit 34.
is supplied to.

As shown in FIG. 2, the control unit 34
RAM36, ROM38, CPU40, clock 4
1, input/output ports 42, 44, output port 46,
48, etc., and each part is connected by a bus line 50 such as a data bus or a control bus.

The input/output port 42 includes a multiplexer 54 having a buffer circuit, an analog/digital (A/
Output signals of the air flow meter 2, cooling water temperature sensor 24, and intake air temperature sensor 4 are supplied via a D converter) 56. In addition, the multiplexer 54, A/
The D converter 56 is controlled by a control signal output from the input/output port 42.

A throttle sensor 18 is connected to the input/output port 44.
The detection outputs of the cylinder discrimination sensor 30 and the rotation angle sensor 32 are also supplied via the waveform shaping circuit 64. Furthermore, the input/output port 44 includes a bandpass filter 60, a peak hold circuit 61, and a channel switching circuit 6.
6. Knock sensor 18 via A/D converter 68
detection output is supplied. A channel switching circuit 66 is connected to the hand pass filter 60 via an integrating circuit 63, and either one of the output signal of the peak hold circuit 61 and the output signal of the integrating circuit 63 is connected to the channel switching circuit 66. is configured to be selected and supplied to the A/D converter 68. Also, peak hold circuit 6
1 is supplied with a reset signal and a gate signal from an input/output port 44. When the engine vibrates due to knocking, this vibration is detected by the knock sensor 22 and a signal of 6 to 8 KHz is supplied to the bandpass filter 60. Since the bandpass filter 60 is configured to attenuate the levels of low and high frequency signals, the output signal of the knock sensor 22 is supplied to the peak hold circuit 61 and the integration circuit 63 via the bandpass filter 60. . Therefore, the peak value of the detection output of the knock sensor 22 is supplied to the input/output port 44 via the peak hold circuit 61, the channel switching circuit 66, and the A/D converter 68. On the other hand, out of the detection output of the knock sensor 22, the band pass filter 6
The integral value of the signal passing through 0 is sent to the input/output port 4 via the channel switching circuit 66 and the A/D converter 68.
4. Then, by comparing the peak value and the integral value of the detection output of the knock sensor 22, the CPU 40 determines whether knocking has occurred.

Further, the output port 46 is connected to the igniter 28 via the drive circuit 70, and the output port 48
is connected to the fuel injection valve 12 via a drive circuit 72. That is, the igniter 28 is supplied with a control signal for controlling the ignition timing, and the fuel injection valve 12 is supplied with a control signal for controlling the fuel injection time.

Further, the ROM 38 stores in advance various data such as map data of basic ignition advance angle expressed by engine speed and intake air amount (or load), basic fuel injection amount, etc., and control programs.
The CPU 40 is configured to perform calculations for controlling the operating state of the engine based on the control program and detection outputs of various sensors. For example, control data for the basic ignition advance angle and basic fuel injection amount are read from the ROM 38 based on the detection output of the air flow meter 2 and the detection output of the rotation angle sensor 32, and based on the detection outputs of the cooling water temperature sensor 24, the intake air temperature sensor 4, etc. A corrected retard amount and corrected fuel injection amount with respect to the basic ignition advance angle and basic fuel injection amount are calculated, and the operations of the igniter 28 and the fuel injection valve 12 are controlled based on the calculated values.

Further, in this embodiment, the throttle sensor 1
Since the sudden acceleration is determined based on the detection output of the throttle sensor 18, the throttle sensor 18 is configured as follows. That is, as shown in FIG. 3, the throttle sensor 18 has a substantially L-shaped rotating piece 80, and the base end of the rotating piece 80 is connected to the rotating shaft 6a of the throttle valve 6. . Also rotating piece 8
At the base end of the rotary piece 80, there is a first portion extending along the distal end of the rotary piece 80 and not in contact with the distal end of the rotary piece 80.
One end of the contact 82 is fixed. Furthermore, a second contact 86 is fixed to the tip of the rotating piece 80, extending parallel to the first contact 82, with an insulating material 84 interposed therebetween. This second contact 86 is grounded. The first contact 82 and the second contact 86 rotate together with the rotating piece 80, and these rotating paths include a comb-shaped first electrode 88 and a second electrode 90.
is installed. The first electrode 88 is the electrode 88
a, 88b, 88c, and 88d, and the second electrode 90 has electrodes 90a, 90b, 90c, and 90d, each electrode 88a to 88d and electrode 90a to 90d.
are arranged alternately. and a first electrode 88,
One end of the second electrode 90 has resistors 92 and 94, respectively.
The controller 34 is connected to the power supply via the
It is connected to the input/output port 44 of.

In the throttle sensor 18, when the throttle valve 6 rotates in the opening direction (in the direction of the arrow in the figure), the rotating piece 80 rotates, and the contacts 82,
The tip of the contact 82 rotates while being in contact with the first electrode 88 and the second electrode 90 alternately. Since the contactor 86 is grounded, when the contactor 82 contacts the electrode 88 and the electrode 90 alternately, the first electrode 88 and the second electrode 9
From 0, a pulse signal as shown in FIG. 4 is output. Note that when the throttle valve 6 rotates in the closing direction, the contact 86 and the contact 82
The first electrode 8 rotates in a non-contact state.
8. No pulse signal is output from the second electrode 90, and the output level of each electrode is maintained at a high level. The output signals of these electrodes 88 and 90 are then supplied to the input/output port 44. Then, when the throttle valve 6 is suddenly opened and the interval between the output pulses of the electrode 88 and the output pulse of the electrode 90 is less than 20 ms, the controller 34 determines that rapid acceleration is occurring.

The present embodiment has the above-described configuration, and its operation will now be explained based on the flowcharts shown in FIGS. 5 to 7. Note that the main routine processing of fuel injection control, air-fuel ratio control, and ignition timing control is the same as the conventional one, so a description thereof will be omitted.

First, as an interrupt routine at the time of sudden acceleration, as shown in FIG. 5, it is determined based on the detection output of the throttle sensor 18 whether or not the interval between output pulses of the electrodes 88 and 90 is within 200 mS ( Step 100). If the determination in this step is NO, the process moves to the next routine, and if the determination is YES, the process moves to step 102. That is, when the throttle valve 6 is suddenly opened and the output pulse generation interval of the electrodes 88 and 90 becomes less than 200 mS, this is a retard amount for correcting the ignition timing, and the retard angle gradually attenuates as time passes. Set the initial value of the amount (step 102). For example, processing is performed to set the initial value of the retard amount Q _ACC as 10° CA. Once this initial value setting has been performed, the process moves to an interrupt routine that is performed every 4 mS, as shown in FIG.

In this routine, first, as shown in step 200, it is determined whether the retard amount _{Q_ACC} is greater than zero. If it is determined as YES in this step, the process moves to step 202 and the retard amount Q _ACC is set to 0.1°CA.
Performs attenuation processing. On the other hand, at step 200
If the determination is NO, proceed to step 204.
Perform processing to set the retard amount Q _ACC to 0°CA. In other words, in this routine, the retard amount Q _ACC is set every 4 mS.
Processing is performed to attenuate by 0.1°CA. Therefore, as shown in Fig. 8, when sudden acceleration is detected at time t ₁ , the retard amount Q _ACC is set as 10° CA, and this retard amount Q _ACC is changed every 4 mS. Performs gradual attenuation processing.

When sudden acceleration is detected in the interrupt routine shown in FIG. 5, the process shown in FIG. 7 is performed. That is, it is determined whether or not knocking has occurred based on the detection output of the knock sensor 22 (step 300). When it is detected in this step that knocking has occurred, the process moves to step 302, where it is determined whether the retard amount _{Q_ACC} is greater than zero. When the determination in this step is YES, the process moves to step 304, where the count value C ₁ of the counter for determining presence of knocking is set to C ₁ +1, and the process moves to step 306. In step 306, it is determined whether the count value _C1 is greater than 2 or not. If the count value _C1 is smaller than 2 in this step, that is, if the determination is NO, the process moves to step 310. In step 310, when knocking occurs for the first time after sudden acceleration (time t ₁ ), the amount of retardation of knocking occurrence (time t ₂ ) is determined.
A process is performed in which Q _ACC is the retard amount and the basic ignition advance angle Q _BSE − retardation effort Q _ACC at time t ₂ is set as the engine ignition timing Qig. For example, the amount of retardation at time t ₂
Q When _ACC is 8° CA, the basic ignition advance angle is from Q _BSE .
Retard control is performed to set the engine ignition timing to the value obtained by subtracting 8°CA.

On the other hand, if the determination in step 306 is YES, that is, if the knock occurs again after time _t2 (time
At t ₃ ), processing is performed to return the retard amount Q _ACC to its initial value, that is, 10° CA. Then, Q _BSE −10°C is treated as the engine ignition timing Qig. That is, when knocking occurs again after time _t2 , it is not sufficient to retard the engine's ignition timing at time _t2 , so at time _t3 , the retardation amount _QACC is set to a value larger than the retardation amount QACC at time _t2 . The ignition timing of the engine is controlled based on the amount of retardation, that is, the initial value. Note that even if knocking occurs after this, the process of returning the retard amount to the initial value is performed.

If the determination in step 302 is NO, the process moves to step 312, where the count value _C1 is set to 0, and the entire process of this routine is completed.

In this way, in this embodiment, the initial value of the retard amount is set for correcting the ignition timing when a sudden acceleration state of the engine is detected, and the retard amount gradually attenuates as time passes. When the occurrence of knocking is detected after setting this initial value, the engine's ignition timing is retarded based on the amount of retardation at the time when the knocking occurred, and when further knocking occurs after this retard control, the ignition timing at the time when the knocking occurs is retarded. By returning the retard amount to its initial value and retarding the engine's ignition timing based on this initial value, knocking can be prevented without causing an unnecessary drop in output or deterioration of acceleration feeling during sudden acceleration. This can be sufficiently suppressed, and damage to the engine due to the occurrence of knocking can be prevented.

In addition, in order to prevent knocking from occurring more than once during sudden acceleration, it is possible to set the initial value of the retard amount to a large value, but if this initial value is increased, there is a risk of misfire. . For this reason, it is desirable to retard the ignition timing of the engine every time knocking occurs, as in the embodiment described above.

〔Effect of the invention〕

As explained above, according to the present invention, when a sudden acceleration state of the engine is detected, the initial value of the retard amount is the retard amount for correcting the ignition timing and gradually attenuates as time passes. When the occurrence of knocking is detected after setting the initial value, the engine's ignition timing is retarded based on the amount of retardation when knocking occurs, and after this retard control, when knocking occurs again. Sometimes, the amount of retardation when this knocking occurs is returned to its initial value, and the engine's ignition timing is retarded based on this initial value.
It is possible to sufficiently suppress the occurrence of knocking during sudden acceleration without causing an unnecessary drop in output or deterioration of acceleration feeling, and the excellent effect of fully contributing to engine protection can be obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an engine to which the device according to the present invention is applied, FIG. 2 is a configuration explanatory diagram of the control section 14,
Fig. 3 is a configuration diagram of the throttle sensor, Fig. 4 is a diagram showing the output waveform of the throttle sensor, Fig. 5 is a flowchart for explaining the processing of the interrupt routine during sudden acceleration, and Fig. 6 is a diagram showing the output waveform of the throttle sensor. A flowchart showing a processing routine for attenuating the amount of retardation during sudden acceleration, FIG. 7 is a flowchart illustrating the processing routine of knock control, and FIG. 8 shows the output signal of the throttle sensor 18 and the amount of retardation. FIG. 6...Throttle valve, 12...Fuel injection valve, 1
4...Engine body, 22...Knock sensor, 2
6...distributor, 34...control unit.

Claims (1)

[Claims] 1 A knock sensor that detects engine vibration,
The throttle sensor detects the opening degree of the throttle valve, and the detection outputs of the throttle sensor and throttle sensor are monitored. After setting the initial value, when the occurrence of knocking is detected by the detection output of the knock sensor, the retard angle at the time of knocking is set. The engine's ignition timing is retarded based on the amount, and if knocking occurs after this retardation control, the retard amount at the time of knocking is returned to the initial value, and the engine's ignition timing is controlled based on this initial value. An ignition timing control device for an internal combustion engine, comprising: a control section that retards the ignition timing of an internal combustion engine.