JPS6235077A - Ignition timing control device in internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the accelerating performance of an engine without occurrence of knocking, by providing a means for setting a maximum spark retardation limit of spark advance, and a means for advancing the maximum spark retardation limit of spark advance in accordance with a predetermined timing. CONSTITUTION:An ignition timing setting means D controls the ignition timing of an internal combustion engine in accordance with the rotational speed and load of an engine. An acceleration detecting means A sets a maximum spark retardation limit of spark advance. When the acceleration detecting means B detects an accelerating condition, a maximum spark retardation limit spark- advancing means C advances the spark angle in accordance with a predetermining timing. With this arrangement, it is possible to enhance the acceleration performance of the engine without occurrence of knocking during abrupt acceleration.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine (hereinafter referred to as engine).

Conventional technology It is known that the ignition timing of a J3 spark ignition engine such as a gasoline engine has a close relationship with the output performance and fuel efficiency of the engine, and R is always adjusted depending on the engine operating condition. This is a so-called electronically controlled ignition timing control device that determines the ignition timing from engine load such as intake air amount and engine speed, and controls the actual ignition timing to obtain the optimum ignition timing. has been put into practical use.

In such an electronically controlled ignition timing control device, when detecting the engine load from the intake air amount, an air 70 meter is generally used to measure the intake air amount.
In this air flow meter, there is a phenomenon in which an intake air amount value that is temporarily larger than the actual intake air amount is output after the throttle valve is suddenly opened due to an increase in the intake air amount during sudden acceleration.

On the other hand, in the electronically controlled ignition timing control device as described above, the ignition timing E is normally adjusted on the high load side where the intake air volume increases.
-y, the above-mentioned phenomenon causes the ignition timing to temporarily become over-retarded, resulting in a problem in that the output decreases and the fuel efficiency deteriorates.

Generally speaking, the ignition timing of an engine is retarded beyond the limit,
In order to prevent ignition from occurring in another cylinder (to prevent flashover), the most retarded limit (hereinafter referred to as lower limit guard) for the ignition advance angle is set, but this problem can be solved. Therefore, an ignition timing control method for an internal combustion engine has been proposed that prevents a drop in engine output during sudden acceleration by temporarily moving this lower limit guard toward the advance side when sudden acceleration is detected. (Unexamined Japanese Patent Publication No. 59-15
No. 3975).

The engine ignition timing control method described in the prior art described above detects sudden acceleration and moves the lower limit guard toward the advance side to maintain a certain set value (constant value) for a predetermined period of time. Therefore, if the set value of this lower limit guard is advanced enough to provide sufficient acceleration performance, knocking may occur immediately after acceleration; If the advance angle is set to a value that is small enough to prevent knocking, there is a problem that acceleration performance during sudden acceleration is insufficient.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an ignition timing control device for an internal combustion engine that overcomes the problems of the prior art described above and ensures sufficient acceleration performance while preventing the occurrence of knocking during sudden acceleration. .

Means for Solving the Problems In order to solve the problems of the prior art described above, the present invention, as shown in the block diagram of FIG. an ignition timing control means for controlling the engine; and an acceleration detection means for detecting the acceleration state of the engine.
means for setting a maximum retardation limit of the ignition advance; and when an acceleration state is detected by the acceleration detecting means, the maximum retardation limit of the ignition advance is set at predetermined timings, for example, every predetermined number of ignitions or every predetermined time. An ignition timing control device for an internal combustion engine is provided.

Function: First, the ignition timing control means advances the ignition timing as the engine speed increases and the engine load decreases, and conversely controls the ignition timing to retard as the engine speed decreases and the engine load increases. do. For example, when the acceleration state of the engine is detected by an acceleration detection means such as the rate of change of the throttle valve opening, the ignition advance angle will be limited by the preset ignition advance maximum retard limit (ignition advance lower limit guard) when the engine suddenly accelerates. Prevents a drop in engine output by controlling the engine so that it does not lag too much. Furthermore, the engine acceleration performance is improved by advancing the lower limit guard stepwise every predetermined number of ignitions or every predetermined time, and regulating the amount of retardation during sudden acceleration using the lower limit guard.

The lower limit guard is a retard angle m that does not cause engine knocking.
This is set so that the advance angle is increased stepwise every predetermined number of ignitions or every predetermined time. According to the present invention, when the engine suddenly accelerates, the lower limit guard advances the ignition timing from the calculated value determined by the ignition timing control means, thereby providing an engine that does not cause knocking and has even better acceleration performance. be able to.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Embodiment FIG. 2 shows an example of an engine to which the present invention is applied, and shows an engine that employs an air flow meter as a measuring means for intake air. However, the engine shown in FIG. 2 is only an example of an engine to which the present invention is applied, and the present invention detects the pressure inside the intake pipe with a pressure sensor instead of the air 70 meter, and uses this pressure to detect the intake air. Of course, it can also be applied to a type of engine that detects.

This engine is controlled by an electronic control circuit such as a microcomputer, and as shown in the figure, is equipped with an air 70 meter 2 as an intake air amount sensor downstream of an air cleaner (not shown). The air 70 meter 2 includes a potentiometer 2B that detects the opening degree of a convention plate 2Δ rotatably provided within the damping chamber. Therefore, the intake air area is detected from the voltage output from the potentiometer 2B. Further, in the vicinity of the air flow meter 2, an intake air fat hood 4 is provided to detect the temperature of intake air.

A throttle valve 6 is arranged downstream of the aphrometer 2, and a throttle sensor 22 that detects sudden engine acceleration and an idle switch that detects the fully open position of the throttle valve 6 are installed on the throttle valve 6. 23 is attached, and a surge tank 8 is provided downstream of the throttle valve 6. 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 is provided with a knocking sensor 18, which is made of a microbon 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.

A spark plug 20 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 made up 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. 3, 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 80 so as to extend in the direction of the distal end of the rotating piece 80 and not 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 86 is grounded. The comb-shaped first electrode 88 and the comb-shaped second -1f pole 90 are arranged to face the first contact 82 with the teeth of the other electrode interposed between the teeth of the electrodes. It is located in 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.

This throttle sensor is connected to the direction in which the throttle valve 6 opens (
When the rotating piece 80 is rotated in the direction of the arrow in the figure), the rotating piece 80 rotates and the first contact 82 and the second contact 86 are rotated.
Since the tip of the first contactor 82 alternately contacts the first electrode 88 and the second electrode 90 and is grounded while the electrodes are in contact with each other,
A pulse signal having a waveform as shown in FIG. 4 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. 5, the electronic control circuit 34 includes a random access memory (RAM) 36 and a read only memory (RO).
M) 38, central processing unit (CPLJ) 40, clock (
CLOCK) 41, a first input/output boat 42, a second input/output boat 44, a first output boat 46, and a second output boat 48, RAM 36, ROM 3
8, CPU 40, CLOCK 41, first input/output boat 42, second input/output boat 44, first output boat 46
and the second output port 48 are connected by a bus 50 such as a data bus or a control bus.

The first input/output boat 42 includes a buffer (not shown),
An air flow meter 2, a cooling water temperature sensor 24, an intake air temperature sensor 4, etc. are connected via a multiplexer 54 and an analog-to-digital (A/D) converter 56. The multiplexer 54 and A/D converter 56 are controlled by a control signal output from the first input/output port 42. The second input/output boat 44 includes a throttle sensor 22
The first electrode 88 and the second electrode 90 are connected, and
An idle switch 23 is connected, and a cylinder discrimination sensor 30 and an engine rotation angle sensor 32 are further connected via a waveform shaping circuit 64. Further, the knocking sensor 18 is connected to the second input/output boat 44 via a bandpass filter 60, a peak bold circuit 61, a channel switching circuit 66, and an A/D converter 68. This bandpass filter 60 is connected to a channel switching circuit 66 via an integrating circuit 63. This channel switching circuit 66 receives a signal for inputting either the output of the peak hold circuit 61 or the output of the integrating circuit 63 to the A/D converter 68.
A reset signal and a gate signal are input to the peak hold circuit 61 from the second input/output port 44.
It is input from.

Further, the first output boat 46 is connected to the invenitor 28 via a drive circuit 70, and the second output boat 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 map and control program for the u-primary ignition advance angle, which is determined based on the amount of intake air per engine revolution and the engine speed. The basic ignition advance angle is read based on the signal input from the angle sensor 32, and the basic ignition advance angle is corrected based on various signals including signals from the cooling water wetness sensor 24 and the air temperature sensor 4. 28 etc. are controlled.

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 invention, the most convenient numerical values will be used to avoid complication, but the present invention is not limited to these numerical values, and can be applied to various engines. The optimal value is selected.

In this embodiment, when an acceleration state is detected, the ignition advance angle during sudden acceleration is regulated by a preset ignition advance lower limit guard, and the lower limit guard is roughly set in steps every predetermined number of ignitions or every predetermined time. This is an ignition timing control device that can provide an engine with good acceleration performance without causing knocking by advancing the ignition timing accordingly.

Next, the operation of the ignition timing control device of the present invention will be explained with reference to the flowchart of FIG. 6th
The figure shows a routine executed at every constant crank angle. First, in step 101, data is read from each sensor such as the airfmeter 2 and the rotation angle sensor 32. Next, in step 102, the intake air amount Q is determined from the air 70 meter signal.
In step 103, intake air ff1Q/N per engine rotation is calculated from the engine rotation speed N. Next, in step 104, the above-mentioned Q/N
The basic ignition timing A is calculated from a map stored in the ROM 38 based on the engine speed N. The relationship between the ignition timing and the engine speed is, for example, as shown in FIG. 7 when the engine load is constant, and this relationship is stored in the ROM 38. This map generally sets the ignition timing to have a certain margin against knocking.

Next, in step 105, the acceleration detection means detects whether or not the vehicle is in an accelerated state. As the acceleration detection means, for example, when the idle switch 23 is turned from on to off,
The rate of change in throttle valve opening, the rate of change in Q/N, the rate of change in intake pipe pressure 1) M, etc. can be used. If it is determined in step 105 that the vehicle is in an accelerated state, it is determined in step 106 whether or not the previous detection was in a steady state. If it is determined in step 106 that the previous detection was not in an acceleration state (or in a steady state), the process proceeds to step 107 and the counter CNT is cleared to O, and in step 108 the counter CNT is counted up.On the other hand, in step 105, the acceleration state If it is determined that this is not the case, or if it is determined in step 106 that the previous detection is not in a steady state, counting up is continued in step 108 without clearing the counter CNT.

Next, in step 109, it is compared whether the value of the counter CNT is 10 or more, and if it is 10 or more, the value of the counter CNT is set to 10 in step 110 to prevent overflow of the counter. Then step 1
Step 11 compares whether the value of the counter CNT is less than a predetermined value α, and if it is less than α, the ignition timing lower limit guard B is set to Ll in step 112.

In step 111, if the value of the counter CNT is larger than α, the process proceeds to step 113 and the counter CNT is
It is compared whether the value of is less than or equal to β which is greater than a. In step 113, if the value of the counter CNT is less than or equal to β, in step 114 the ignition timing lower limit guard B is set to 12, which is greater than Ll (advanced). If the value of the counter CNT is greater than β in step 113, the process proceeds to step 115, and the lower limit guard B at the time of ignition is set to L3 (advanced by more than 2).

Here, the values of α and β mentioned above may be determined according to a predetermined number of ignitions after acceleration is detected, or may be determined according to a predetermined time. When determining the values of α and β according to a predetermined number of ignitions, the above process is performed in one step.
Execute every 20° crank angle (12° for a 6-cylinder engine.

(in order to ignite once for each ignition), the value of the counter CNT is incremented by one for each ignition. For example, if 4 ignitions are used for α and 5 ignitions are used for β, α-4 and β=5. However, as mentioned above, the counter CNT is incremented by one at regular time intervals, for example, every 4 ms.
The process shown in the figure may be executed at regular time intervals.

Furthermore, Ll, L2, and L3 are each, for example, -5 degrees B
The settings should be TD010 degrees BTDC, 5 degrees BTDC, etc. However, these values are not limited, and of course other ignition advance angles may be used.

If the ignition advance lower limit guard has been set according to each counter value in steps 112, 114, and 115, the process proceeds to step 116, where the ignition timing A calculated in step 104 and the lower limit guard B are compared. If the ignition timing A is smaller than the lower limit guard B, that is, if the advance value of the ignition timing A is behind the lower limit guard B, step 1
17, the ignition timing A is set to an advance value regulated by the lower limit guard value. In step 116, if the ignition timing A is greater than the lower limit guard B, and in step 117
After setting ignition timing A to lower limit guard B,
The program proceeds to step 118, stores the ignition timing A in the RAM 36, and ends this routine.

As described in detail above, in this embodiment, after detecting the acceleration state, the lower limit guard is raised stepwise every predetermined number of ignitions or every predetermined time to ensure the acceleration performance of the engine during sudden acceleration. This will be explained in an easy-to-understand manner with reference to FIG. In FIG. 8, an idle switch is employed as the acceleration detecting means, and FIG. 8A shows the time of slow acceleration, and FIG. 8B shows the time of sudden acceleration. During slow acceleration, Q/N, N
Since the basic ignition timing determined by the engine is not retarded that much,
Ignition timing is determined without being affected by the lower limit guard. On the other hand, during sudden acceleration, the basic ignition timing is rapidly retarded and becomes below the lower limit guard, as shown in FIG. 8B. In the present invention, a lower limit guard for ignition timing is provided, and by raising the lower limit guard in a stepwise manner, the ignition timing during sudden acceleration is regulated by the lower limit guard, so that acceleration performance during sudden acceleration can be improved.

The present invention has been described above in detail with respect to specific embodiments, but
Of course, the present invention is not limited to these embodiments, and many modifications may be made within the IFB of the present invention.

As described in detail above, the present invention is configured to raise the ignition advance lower limit guard in a stepwise manner according to the predetermined number of ignitions or according to the predetermined time, thereby preventing the occurrence of knocking during sudden acceleration. This has the effect that acceleration performance can be improved without any interference.

Another method to achieve both acceleration performance and knock prevention during sudden acceleration is to temporarily advance the ignition timing for intake air and the ignition timing itself, which is calculated from the engine speed, after sluggish acceleration. However, it is difficult to match the intake air condition and the ignition timing, making control complicated. The present invention also has the effect of achieving both acceleration performance and knocking prevention with simple control.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a schematic diagram showing an example of an engine to which the present invention is applied, Fig. 3 is a circuit diagram showing details of a throttle sensor, and Fig. 4 is a throttle sensor. 5 is a block diagram showing details of the electronic control circuit of FIG. 2, FIG. 6 is a flowchart showing a processing routine of an embodiment of the present invention, and FIG. A graph showing an example of the relationship between the engine speed and the ignition timing when the engine load is constant, and Fig. 8 is an explanatory diagram showing the relationship between the ignition timing calculation result and the lower limit guard, where A is during slow acceleration and B is at sudden acceleration. Indicates when accelerating. 2... Air flow meter, 6... Throttle valve, 22... Throttle sensor, 23... Idle switch, 32... Rotation angle sensor, 34... Electronic control circuit. Applicant: Toyota Motor Corporation Figure 1 Figure 3 Figure 4 Figure 2 Figure 5. Figure 7. Gotsukun rotation 4 times (rpm) Figure 8.

Claims (1)

[Claims] ignition timing control means for controlling ignition timing of an internal combustion engine according to engine speed and load; acceleration detection means for detecting an acceleration state of the engine; means for setting a maximum retardation limit of ignition advance; and said acceleration detection means. An ignition timing control device for an internal combustion engine, comprising means for advancing the ignition advance maximum retard limit according to a predetermined timing when an acceleration state is detected by the means.