JPH0672588B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an internal combustion engine, and more specifically to detecting and avoiding knocking and performing advance correction after avoidance for engine operating conditions. The present invention relates to an ignition timing control device for an internal combustion engine configured to be determined in consideration.

(Prior Art) Even in a conventional ignition timing control device for an internal combustion engine, it is well known that knocking is detected and the ignition timing is corrected. Is set uniformly throughout all operating states of the engine,
Waiting for the number of ignitions to start, advancement was started. As an example thereof, the technique described in JP-A-55-91765 can be mentioned.

(Problems to be solved by the invention) It is desirable for the internal combustion engine to ignite in the vicinity of the trace knock at the time of low speed running in order to obtain the optimum output, but at the time of high speed running, engine damage due to frequent knocking and deterioration of durability It is necessary to control below that in consideration. Therefore the second
As shown in the figure, it is desirable to suppress the knock occurrence frequency level during steady running below the knock occurrence reference frequency (solid line a) that corresponds to the above-described trace knock and that is determined by the engine characteristics and is inversely proportional to the engine speed. Dashed line b). On the other hand,
During transient operation, especially during sudden acceleration, the knocking frequency must be slightly increased due to the increase in output, but it is necessary to suppress it below a predetermined limit to protect the engine (dashed line c). Therefore, when determining the advance angle correction after avoiding knocking, change the knock occurrence frequency in consideration of the engine speed, and set multiple kinds of knock occurrence frequency levels according to changes in steady operation and transient operation. As a result, even if the engine speed increases or decreases, it is possible to control the knock occurrence frequency to be uniform over time, and it is possible to obtain optimum output and drivability, which can also have a favorable effect on the engine itself. .

However, in the conventional technique, since the uniform advance method is used, the knocking frequency varies with time as the engine speed changes, which makes it difficult to perform optimal control as described above. Further, the advance angle characteristic was not changed between the steady operation and the transient operation state. On the other hand, it has been proposed to change the knock determination level according to the engine speed, as in the technique described in Japanese Patent Laid-Open No. 61-23873, but this technique has been limited to showing the knock detecting means.

Therefore, an object of the present invention is to eliminate such drawbacks of the prior art, while maintaining an optimal knock occurrence frequency that becomes uniform over time despite changes in engine speed,
It is an object of the present invention to provide an ignition timing control device for an internal combustion engine, which is capable of performing advance angle correction that makes engine protection and engine output demand compatible with each other in response to changes in the engine operating state.

(Means and Actions for Solving Problems) In order to achieve the above object, the present invention, as shown in FIG. 1, includes an operating state detecting means 10 for detecting the operating state of an engine, and an operating state detecting means. Basic ignition timing calculation means 12 for inputting an output to calculate the basic ignition timing of the engine, knocking detection means 14 for detecting knocking generated in the engine combustion chamber, inputting outputs of the knocking detection means and the basic ignition timing calculation means Of an internal combustion engine having a knocking correction amount calculating means 16 for correcting the basic ignition timing at the time of knocking by a predetermined amount and an ignition means 18 for inputting an output of the knocking correction amount calculating means to ignite the air-fuel mixture in the engine combustion chamber. In the ignition timing control device, the knocking correction amount calculation means retards the ignition timing by a predetermined amount when knocking is detected, and when knocking is not detected, The first allowable knocking frequency corresponding to the transient operating state of the engine, which is set so as to decrease as the function speed increases, is compared with the actual knocking frequency, and the actual knocking frequency is the first allowable knocking frequency. When the knocking occurrence frequency is equal to or higher than the ignition timing, the ignition timing is maintained, and when the knocking occurrence frequency is less than the first allowable knocking occurrence frequency, the engine speed is similarly decreased as the engine speed increases. When the actual knocking occurrence frequency is less than the second allowable knocking occurrence frequency as compared with the second allowable knocking occurrence frequency corresponding to the steady operation state of the engine set in advance so that the value decreases with respect to The ignition timing is configured to be advanced by a predetermined amount.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 3 is a block diagram of an apparatus according to the present invention. In the figure, reference numeral 20 denotes a crank angle sensor arranged in the vicinity of the rotating portion of the internal combustion engine 22, and detects the rotation angle of the crank shaft accompanying the vertical movement of the piston 24. A negative pressure sensor 28 is arranged downstream of the throttle valve 26 in the air introduction path of the internal combustion engine 22 to detect the load state of the engine. The crank angle sensor 20 and the negative pressure sensor 28 constitute the above-mentioned operating state detecting means 10.

The internal combustion engine 22 further includes a cylinder head 30 and a knock sensor.
32 is provided to detect the combustion pressure in the combustion chamber 34. The output of the knock sensor 32 is input to the control unit 36, where only the knocking frequency is extracted by the bandpass filter 38, and then input to the knocking detection circuit 40 including a comparator, and compared therewith to a predetermined level and knocking is performed. Presence or absence of occurrence is detected. The knocking detection circuit 40, the knock sensor 32, and the bandpass filter 38 constitute the knocking detection means 14 described above.

The control unit 36 includes an input / output interface 36a, a CPU 36b
And a memory 36c, and is mainly composed of a microcomputer, and functions as the basic ignition timing calculation means 12 and the knocking correction amount calculation means 16 described above. The output of the knocking detection circuit 40 described above is input to the CPU 36b of the control unit 36, and the output of the crank angle sensor 20 is also subjected to waveform shaping by the waveform shaping circuit 42 and is also input to the negative pressure sensor 28. The output is also digitally converted by the A / D conversion circuit 44 and input, and the control unit 36 calculates the basic ignition timing and the knocking correction amount according to these outputs.

The ignition device 18, which is the above-mentioned ignition means, is provided at the next stage of the control unit 36, and ignites the air-fuel mixture in the combustion chamber 34 via the ignition plug 46 according to the output of the control unit 36.

Next, the operation of the device according to the present invention will be described with reference to the flow chart of FIG.

First, in step 50, the basic ignition timing θb is calculated. This is performed by searching the control value table of the basic ignition timing stored in the memory 36c of the control unit 36 based on the outputs of the crank angle sensor 20 and the negative pressure sensor 28.
Note that corrections other than knocking correction may be appropriately added based on the output of a water temperature sensor (not shown).

Subsequently, in step 52, the reference knocking ignition number is determined from the engine speed N detected by the crank angle sensor 20.
Ikr, advance angle determination ignition number In, and advance angle standby ignition number Iw are selected. This is for the calculation of the knock occurrence frequency described later.
FIG. 5 shows these values which are different according to the engine speed, and these values are stored in the memory 36 of the control unit 36.
It is stored in c and is selected as appropriate from the engine speed.
The characteristic curve of the value shown in FIG. 5 is determined based on the knock occurrence frequency level of FIG.
Ikr / In is the knock occurrence frequency level during transient (Fig. 2c),
1 / Iw corresponds to the knock occurrence frequency level at steady state (Fig. 2b). Thus, the advance waiting ignition number Iw can be understood as the reciprocal value of the knock occurrence rate in that it also means that the knock occurrence is allowed once per the ignition number.

Subsequently, in step 54, it is determined whether or not knocking has occurred this time, and if it has occurred, the knock correction amount θkc is retarded by 1 degree in step 56 (note that subtraction is delayed in this flow chart, Addition means advance.
Also, the knock correction amount θkc is an initial value “0”).

If there is no knocking, continue with step
At 58, the knock occurrence rate Ikr / In is determined. This knock occurrence rate is during transient running as described above.
Reference knock generation ignition count Ikr / advance angle judgment score In selected in 52
Compare the value calculated with the actual knock generation ignition number Ika / advance angle determination point In with the value calculated, and if Ika / In exceeds Ikr / In, advance angle correction is stopped (step 60) .

If the knock occurrence rate is less than the predetermined value in step 58,
Subsequently, in step 62, it is determined whether the advance standby ignition number Iw, which is the reciprocal of the knock occurrence rate during steady running, has elapsed. If it has not elapsed, advance angle correction is stopped, and if it has elapsed, advance angle correction is performed once. (Steps 60, 64). Finally, at step 66, the corrected ignition timing θkc (positive or negative value) is added to the basic ignition timing θb to determine the ignition timing θig.

FIG. 6 shows an example of control based on this flow chart. In this figure, assuming that the time point "a" is the current time and the reference knocking ignition number Ikr is two times, a section (i. The number of knocks actually generated in In is one, so the knock occurrence rate at transition (Ika / In = 1 / In) in step 58 is less than a predetermined value (Ikr / In = 2 / In), In the subsequent steady state knock occurrence rate determination step 62, if the predetermined advance ignition standby ignition number Iw has elapsed, the advance is corrected once. That is, in the figure, it can be estimated that there is frequent knocking before the start of the section In and it is a transient running state,
By inserting the transient knock occurrence rate determination step 58, it is possible to temporarily reduce the knock occurrence frequency and protect the engine. In the prior art, such a judgment step is not involved, and the number of ignitions in the advance standby ignition is uniform.Therefore, the standby time is short at a high rotation speed, and therefore the advance is immediately advanced. Therefore, knocking, retardation, advancement However, there was an inconvenience that repeated knock generation adversely affected the engine.

Since the present invention eliminates such a disadvantage by inserting the transition time determination step 58, and also increases or decreases the advance standby ignition number in the subsequent steady state determination step 62 in proportion to the change in the engine speed, In both the region and the low rotation region, the knock occurrence frequency can be made uniform over time, and optimum control can be performed while satisfying both the engine output request and the engine protection.

(Effect of the Invention) The present invention retards the ignition timing by a predetermined amount when knocking is detected, and when knocking is not detected, the engine is set in advance so as to decrease as the engine speed increases. The first allowable knocking occurrence frequency corresponding to the transient operating state is compared with the actual knocking occurrence frequency, and when the actual knocking occurrence frequency is equal to or higher than the first allowable knocking occurrence frequency, the ignition timing is held and When the engine speed is less than the allowable knocking occurrence frequency, the engine steady state is preset so that the engine speed decreases as the engine speed increases and the value decreases with respect to the first allowable knocking occurrence frequency. Compared with the second allowable knocking occurrence frequency corresponding to the operating state, and when the actual knocking occurrence frequency is less than the second allowable knocking occurrence frequency, the ignition timing is set to a predetermined amount. Since it is configured to correct the advance angle, the knocking occurrence frequency becomes uniform over time even if the engine speed changes, and the allowable knocking occurrence frequency occurs during a transient time when the engine output is required to increase, such as during sudden acceleration. Is set to a large value in order to respond to it, and in that case as well, control is performed within the prescribed limits, so optimal output is obtained, driveability is improved, and there is no risk of engine damage, resulting in any operation. Optimal engine ignition timing control can be performed depending on the state.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is an explanatory diagram of a control method of the present invention, FIG. 3 is a block diagram showing a configuration of an apparatus according to the present invention, and FIG. 4 is a flow chart showing the operation thereof. A chart, FIG. 5 is an explanatory diagram showing the calculation coefficient of the knock occurrence rate, and FIG. 6 is an explanatory diagram showing a control example based on the flow chart of FIG. 10 ... Operating state detection means (crank angle sensor 20, negative pressure sensor 28), 12 ... Basic ignition timing calculation means, 14 ... Knocking detection means (knock sensor 32, bandpass filter 3)
8, knocking detection circuit 40), 16 ... Knocking correction amount calculation means, 18 ... Ignition means (ignition device), 36 ... Control unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Nagao 1-4-1 Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (56) Reference JP-A-61-23873 (JP, A) JP 58-217775 (JP, A)

Claims (1)

[Claims] Claims: 1. a. Operating state detecting means for detecting the operating state of the engine; b. Basic ignition timing calculating means for inputting the output of the operating state detecting means to calculate the basic ignition timing of the engine; c. Engine combustion Knocking detection means for detecting knocking occurring in the chamber, d. Knocking correction amount calculation means for inputting the outputs of the knocking detection means and the basic ignition timing calculation means, and correcting the basic ignition timing by a predetermined amount during knocking, and e. An ignition timing control device for an internal combustion engine, comprising: an ignition means for inputting an output of the knocking correction amount calculating means to ignite an air-fuel mixture in an engine combustion chamber, wherein the knocking correction amount calculating means detects knocking. The ignition timing is retarded by a predetermined amount, and when knocking is not detected, it is set to a preset engine transient operation state that decreases as the engine speed increases. The first allowable knocking occurrence frequency is compared with the actual knocking occurrence frequency. If the actual knocking occurrence frequency is equal to or higher than the first allowable knocking occurrence frequency, the ignition timing is held and the first allowable knocking occurrence occurs. When the frequency is less than
Similarly, the second value corresponding to the steady operation state of the engine, which is set in advance such that the engine speed decreases as the engine speed increases and the value decreases with respect to the first allowable knocking occurrence frequency,
The ignition timing control of the internal combustion engine is configured to advance the ignition timing by a predetermined amount when the actual knocking occurrence frequency is less than the second allowable knocking occurrence frequency. apparatus.