JPH0751925B2 - Ignition timing control method for internal combustion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ignition timing control method for an internal combustion engine, and more specifically, correcting an ignition timing by detecting an acceleration state of engine operation based on a throttle valve opening degree and the like. And an ignition timing control method for an internal combustion engine configured as described above.

(Problems to be Solved by Conventional Techniques and Inventions) Recently, ignition timing control of an internal combustion engine is becoming electronically controlled. However, in such an electronic control system, acceleration is performed, especially when starting and accelerating from around idle or from an intermediate vehicle speed. There was a case where knocking occurred temporarily at the time of sudden acceleration. It has recently been found that such a phenomenon is caused by the fact that the engine speed temporarily decreases during acceleration as shown in FIG. 2, for example, during several ignitions, and then increases. That is, in the ignition timing control of the electronic control system, the basic value is usually calculated from the engine speed and the intake negative pressure or the intake air amount, but the opening operation of the throttle valve immediately causes the intake negative pressure or It may not be detected as a change in the intake air amount, and there may be some detection delay, and the engine speed may be detected only once within one TDC cycle. It turned out that there are cases where it will be ignited. Further, when the ignition timing is once converted into time and is controlled, the angle-time conversion is performed based on the cycle in the angular section such as the crank angle of 30 degrees, so that the ignition timing itself advances as shown in FIG. In addition to the phenomenon that it shifts to the corner side, the cycle itself is gradually extended and the cycle of the section that was the basis of the calculation is different from the cycle of the section to be ignited. Will be lost.

By the way, Japanese Patent Application Laid-Open No. 59-65568 describes a technique for retarding the ignition timing for a certain period of time when a sudden engine acceleration is detected. Although it is common to the present invention in terms of retarding at the time of acceleration, this prior art is made for the purpose of reducing a vehicle body shock due to a discontinuous increase in combustion pressure generated at the time of sudden acceleration, Not only is the purpose different from that of the present invention, but in the case of this prior art, not only in the configuration but also in the case of this prior art, the engine is retarded immediately at the time of sudden acceleration, but the present invention is only at the time of acceleration and when the engine speed is decreasing. In the case of the prior art, in contrast to the fixed value which is a fixed time in the case of the prior art, in contrast to the case of the present invention, the fluctuation of the engine speed is detected and delayed only while it is decreasing. Therefore, the engine output is not unnecessarily reduced by excessively retarding.

As described above, an object of the present invention is to provide an ignition timing control method for an internal combustion engine that effectively avoids knocking due to a temporary decrease in engine speed during acceleration.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present invention is directed to an internal combustion engine that controls ignition timing by an optimum value determined according to the operating state of the engine, as shown in FIG. In the ignition timing control method, the acceleration state is detected from at least the throttle valve opening and / or the change amount of the throttle valve opening, and the fluctuation rate of the engine speed is calculated, and the engine speed is in a decreasing direction in the detected acceleration state. In this case, the ignition timing is configured to be retarded (steps 10 to 16).

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings. For the sake of convenience, an apparatus used for realizing the ignition timing control method for an internal combustion engine according to the present invention will be described first with reference to FIG.

As shown in the figure, an internal combustion engine not shown (six cylinders)
A crank angle sensor 20 composed of an electromagnetic pickup or the like is arranged in the vicinity of the crank shaft or the cam shaft (neither is shown), etc., and as shown in FIG. The TDC signal is generated every 30 degrees, and the unit angle signal for time conversion and engine speed Ne calculation is generated every 30 degrees. The 3
The seed signal is input to the control unit 22 where it is waveform shaped via the waveform shaping circuit 24. A microcomputer 26 is connected to the next stage of the waveform shaping circuit 24, and the circuit 24
Is output to the input interface circuit 26a.

A pressure sensor 28 for detecting the absolute pressure of the air passage is provided at an appropriate position downstream of a throttle valve (not shown) of intake air (not shown) of the internal combustion engine to detect the load state of the engine. To do. Further, a throttle sensor 30 for detecting the amount of change in the opening of the throttle valve is provided to detect the amount of change in the opening of the throttle valve linked with the accelerator pedal (not shown). Further, a water temperature sensor 32 is provided at an appropriate position of an engine cooling water passage (not shown) to detect the cooling water temperature, and the outputs of these sensors are appropriately widened through a level correction circuit 34, and then A / It is input to the D conversion circuit 26b. Further, a voltage signal is sent from the battery 36, and the signal is also input to the A / D conversion circuit 26b via the level correction circuit 34. micro·
In the computer 26, the CPU 26c calculates the ignition timing by using the ROM 26d and the RAM 26e based on the detected value, and after time conversion as described later, outputs it to the drive circuit 38 of the subsequent stage via the output interface circuit 26f. 38 mainly comprises a power transistor 38a, which is turned on by the output signal of the microcomputer 26 as shown in FIG. The transistor 38a is turned off when the output signal from the microcomputer 26 falls to a low level to generate a high voltage in the secondary coil of the time coil 40,
The high voltage discharges between the electrodes of the ignition plug 44 of a predetermined cylinder via the distributor 42 to ignite it. In this case, the ignition order is the order of the first, fifth, third, sixth, second and fourth cylinders. Incidentally, the microcomputer 26
Further comprises an energization timer counter for controlling the transistor on time and an ignition timer counter for controlling the transistor off time, and the cycle of the angular interval between the unit angle signals (hereinafter referred to as “stage” sn) (engine rotation). It has a timer counter for measuring speed) tsn and a stage counter (all not shown) for counting stages.

Next, an embodiment of the control method according to the present invention will be described with reference to the flow chart of FIG. This calculation is started every 30 degrees when the unit angle signal is generated.

First, in step 50, it is detected whether or not the engine operation is in an accelerating state from the output of the throttle sensor 30, and if it is in an accelerating state, then in step 52, the engine speed
The fluctuation rate dNe of Ne is calculated. This is performed using the output of the stage cycle timer counter, and is calculated by comparing the cycles of the preceding stage and the stage immediately before it.

Then, in step 54, the engine speed fluctuation rate dNe
Is greater than or equal to a predetermined reduction rate, and if it is greater than or equal to the predetermined value, the acceleration correction value θKA (initial value zero) is set to a predetermined value θ
ACC is subtracted (step 56). In this flow chart, subtraction means retard correction and addition means advance correction.

If it is determined in step 54 that the engine speed fluctuation rate dNe is smaller than the predetermined decrease rate, then in step 58, the engine speed fluctuation rate dNe is, on the contrary, whether or not the predetermined value increase rate or more, that is, In FIG. 2, after reversing the engine speed in the increasing direction, it is judged whether or not the increasing degree is a predetermined value or more,
If it has increased by a predetermined value or more, in step 60 the fixed value θACC is added to the acceleration correction value θKA to advance back,
If this is not the case, it is assumed that the advance is not made in advance (step 6).
2). If acceleration is not detected in step 50, retard correction is not performed (step 64). The above calculation
It is performed every 30 degrees and the acceleration correction value θKA is calculated each time.

Next, the overall ignition timing will be described. At a predetermined angle, for example, the TDC position, the main calculation procedure shown in FIG. 7 is started, and first, at step 100, the ignition timing θb is calculated. This is determined by searching the map value in the ROM 26d from the engine speed Ne and the pressure value Pba, and subsequently adding the correction of the water temperature and the like as appropriate.

Then, in step 102, the final ignition timing θig is determined by adding the acceleration correction value θKA calculated in the flow chart of FIG. 6 to the ignition timing θb, and in step 104, the time is set based on an appropriate stage cycle tsn. After conversion, in step 106, as shown in FIG. 4, the ignition timer is started to ignite. In the time conversion, the cycle varies greatly from stage to stage as shown in FIG. 3, so the period of the stage closer to the scheduled ignition stage is used. still,
Although not shown, it goes without saying that the energization time is similarly determined, the time is converted, and the energization timer is appropriately started at the stage to energize as shown in FIG.

FIG. 8 and FIG. 9 show a second embodiment of the present invention, showing an example of ignition at a fixed angle when acceleration is detected. Explaining only the points different from FIG. 6,
When it is determined in step 74 that the engine speed has decreased by a predetermined value or more, the ignition timing is fixed to a predetermined angle (step 76), and the ignition timing θig is also determined in the ignition timing calculation flow chart of FIG. If the fixed angle value is determined in FIG. 8, it is preferentially followed (step 200). It has an advantage that the control can be simplified as compared with the first embodiment. Needless to say, the return advance angle may be added when the rotational speed fluctuation rate increases by a predetermined rate or more as in the first embodiment.

(Effects of the Invention) The present invention detects the acceleration state from the amount of change of the throttle valve opening, calculates the engine speed variation rate, and retards the ignition timing when the engine speed is decreasing in the acceleration state. With such a configuration, there is an advantage that it is possible to effectively avoid knocking that temporarily occurs during acceleration.
Also, since the retard angle region is limited to the case where the engine speed is in the decreasing direction, it is possible to keep it within the minimum range necessary to avoid the retard angle correction knocking, and prevent unnecessary reduction of the engine output. It has the advantage that

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the ignition timing control method for an internal combustion engine according to the present invention, FIG. 2 is an explanatory graph showing fluctuations in engine speed during engine acceleration, and FIG. 3 is an engine in an angle-time conversion control system. FIG. 4 is an explanatory graph showing the influence of fluctuations in the rotational speed on the ignition timing, FIG. 4 is a block diagram showing the configuration of an apparatus used to realize the present method, FIG. 5 is a timing chart showing its operation, and FIG. 7 and FIG. 7 are explanatory flow charts showing an embodiment of the present invention, and FIGS. 8 and 9 are explanatory flow charts showing a second embodiment of the present invention.

Claims (4)

[Claims] 1. An ignition timing control method for an internal combustion engine, wherein ignition timing is controlled by an optimum value determined in accordance with an operating state of the internal combustion engine, wherein acceleration is at least based on a throttle valve opening and / or a variation of the throttle valve opening. An ignition timing control method for an internal combustion engine, comprising: detecting a state, calculating a fluctuation rate of an engine speed, and retarding the ignition timing when the engine speed is in a decreasing direction in a detected acceleration state. 2. The ignition timing control method for an internal combustion engine according to claim 1, wherein retardation correction is performed when the engine speed fluctuation rate exceeds a predetermined value in the decreasing direction. 3. The ignition timing control method for an internal combustion engine according to claim 2, wherein the retard correction is performed while the engine speed fluctuation rate exceeds the predetermined value. 4. The ignition timing control method for an internal combustion engine according to claim 2, wherein the ignition timing corrected for retarding is set to a fixed angle.