JPH0680307B2 - 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.

Conventional Techniques and Problems Conventionally, a basic ignition timing is set according to the engine speed and the engine load (intake pipe pressure or intake air amount per engine revolution), and according to the engine cooling water temperature or the intake air temperature. An ignition timing control method is known in which ignition is performed with an ignition timing in which the basic ignition advance is corrected. In such an internal combustion engine, a knocking sensor for detecting engine vibration is attached to the engine body,
When knocking is detected, the ignition timing is retarded by a predetermined amount to control to an optimum ignition timing at which knocking does not occur. In such an engine, the intake air amount (load) detection delay time and the control system delay response time occur until the ignition timing is retarded according to the knocking state. By comparison, it is possible to control the optimum ignition timing for a slow change in the knocking state.

By the way, in a transient operation state where the throttle valve suddenly opens and accelerates, the knocking limit, which is the limit at which minute knocking occurs, suddenly changes to the retard side, and transient transition occurs in several ignitions in the transient operation state at the initial stage of acceleration. It is known that various notkings occur. The time between several ignitions is sufficiently shorter than the delay response time of the control system, etc. Therefore, the control system using the above-mentioned knocking sensor cannot prevent the occurrence of knocking. There was a problem. In order to solve this problem, in the invention described in JP-A-57-99269, the sudden acceleration is detected and the ignition timing is corrected to the retard side only for a predetermined time or a predetermined number of ignitions. I have to. However, a certain amount of time is required to detect acceleration above a predetermined level, and in particular, when accelerating from the fully closed throttle, knocking may already occur before the acceleration is determined. In Japanese Patent Application No. 58-54500 proposed by the applicant of the present application, a constant crank on the retard side from the basic ignition advance angle for a predetermined number of ignitions from the reference is based on the time when the throttle valve is closed from the fully closed state. Disclosed is a technique in which ignition is performed at a corner. However, this technique can be applied only when the acceleration transition occurs after the throttle valve is fully closed, and there remains a problem when accelerating from a low speed operation.

Means for Solving Problems The basic ignition timing can be obtained by interpolation calculation from a two-dimensional map similar to the conventional one in which engine speed and load are given as parameters. In the present invention, as shown by the solid line in FIG. 3, for example, the maximum allowable advance angle change width is predetermined as a map or as a function with the opening change amount of the throttle valve as a parameter. The amount of advance change for each ignition due to the ignition timing is suppressed within this maximum allowable advance change range. Explaining in more detail with reference to FIG. 3, when the advance angle change amount for each ignition is larger than the maximum allowable advance angle change width (solid line) as shown by the chain double-dashed line, the maximum ignition timing is larger than the previous ignition timing. The angle is advanced by the amount of the allowable angle change range. At this time, the amount of advance change (two-dot chain line) obtained from the basic ignition timing and the maximum allowable advance change width (solid line)
It will be retarded by the difference. Knocking to prevent knocking during transition due to over-advancement.

Example Since an ignition device for an internal combustion engine equipped with an igniter and a distributor is known, a description of such a system configuration will be omitted. The invention relates to the ignition timing control of such an ignition device, which is achieved by the use of a microcomputer known per se as shown in FIG. 2, the functional blocks of which are shown in FIG. ,
The flow chart is shown in FIG.

Referring to FIG. 2, a control device 10 including a microcomputer includes a central processing unit (CPU) 12, a read only memory (ROM) 14, and a random access memory (RAM) 16, which are connected by a bus 18. . Controller 10
Also has a clock (CL) 20. The control device 10 has a load sensor 24 and a rotation speed sensor via the input / output port 22.
26, the throttle position sensor 28 and other detector signals are input, and a control output processed based on the detector signals is output to the ignition device 30. Data for calculating the basic ignition timing, data for calculating the maximum allowable advance angle change width as shown in FIG. 3, and a program are stored in the ROM 14.

FIG. 4 is a program for ignition timing control performed every 180 ° C. In step 40, the engine speed Ne is read, and in step 41, the basic injection time Tp is read. In this case, the basic injection time Tp represents the engine load, and is calculated in another routine based on the detected values of the intake air amount, the intake pipe negative pressure, and the like.

In step 42, the ignition timing SA is obtained by the interpolation calculation of the basic ignition timing from the read rotational speed and load and the stored two-dimensional map. Reading Surotsutoru valve opening V _THR at step 43. Next, at step 44, it is judged if the engine speed Ne is smaller than the reference speed Ne _Ref (for example, 2400 rpm), and if No, SA is output. This is because knocking does not easily occur if the engine speed increases to some extent. If yes, go to step 45,
Obtain the maximum allowable advance angle change width A _Ref . A _Ref is stored in advance as a map or as a function in correspondence with the opening change amount of the throttle valve as shown in FIG. 3, and the opening change amount of the throttle valve as a parameter is the opening V read this time. _The difference _obtained by subtracting the previous opening degree V _THROLD from _THR can be used, and the previous opening degree is stored in the RAM 16 as a value updated for each cycle.

In step 46, the difference obtained by subtracting the previous ignition timing SA _OLD from the current ignition timing SA obtained in the same manner is the advance angle change amount for each ignition, and this is obtained corresponding to the opening change amount of the throttle valve. The maximum allowable advance change width A _Ref is compared. In the case of Yes, it means that the amount of advance angle change is below the maximum permissible amount of advance angle change shown by the solid line in FIG.
Similarly to, the SA value obtained in step 42 is output. If No, step 47 sets SA = SA _OLD + A _Ref , that is,
The SA value is output in step 48 by advancing the maximum allowable advance angle change range from the previous ignition timing. In this series of operations, the advance angle change amount for each ignition is suppressed within the maximum allowable advance angle change range set corresponding to the throttle valve opening change amount. The above description was made with reference to when the throttle valve is operated to the open side, but when operated to the closed side, if the maximum allowable advance angle variation is set to 0, the conventional ignition timing is obtained. be able to.

FIG. 1 is obtained by extracting the above-mentioned flow as a functional block, and each function from block 50 to block 66 will be apparent from the above description. According to the present invention, by introducing the idea of the change of the opening degree of the throttle valve for each ignition, the ignition timing at the time of acceleration is corrected without a response delay and knocking is prevented, and further, the acceleration from any position of the throttle valve is accelerated. Will also be able to deal with.

Effects of the Invention As described above, according to the present invention, it is possible to reliably prevent the occurrence of knocking.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a control device adopted in the present invention,
FIG. 2 is a block diagram of the control device, FIG. 3 is a graph showing an example of the maximum allowable advance angle change width, and FIG. 4 is a flowchart of ignition timing control. 10 ... Control device, 24 ... Load sensor, 26 ... Rotation speed sensor, 18 ... Throttle position sensor, 30 ... Ignition device.

Claims (1)

[Claims] Claim: What is claimed is: 1. An ignition timing control method for an internal combustion engine, wherein a basic ignition timing is obtained in a predetermined relationship corresponding to an engine speed and an engine load. The maximum allowable advance angle change width, which is the maximum allowable value of the advance angle amount of the ignition timing at the time of execution, is set in advance so as to increase as the change amount of the throttle valve opening increases. An ignition timing control method for an internal combustion engine, characterized in that a magnitude of a timing advance angle amount is suppressed within the maximum allowable advance angle change width.