JPS58202374A - Engine ignition timing control device - Google Patents

Abstract

PURPOSE:To improve an engine output in summer by advancing ignition timing by a prescribed angle when the intake air temperature exceeds a value corresponding to the fresh air temperature in summer. CONSTITUTION:When the intake air temperature exceeds the fresh air temperature in summer, a flug 2 is set. In the step 142, whether the flag 2 is set or not is judged. If the flag 2 has been set, the amount of correction DELTAtheta is made 3 deg., and if the flag 2 has not been set, the amount of correction DELTAtheta is made 0 deg.. In the step 148, an ignition timing operation is performed, and the amount of correction DELTAtheta is added. Hereby, no knocking is produced even if the ignition timing is advanced since the knocking is hardly to be produced in summer, enabling an engine output to be improved.

Description

[Detailed description of the invention] The present invention relates to an ignition timing control device for an engine.

15 vr Specifically, the present invention relates to an engine ignition timing control device that optimally controls -C ignition timing according to outside temperature.

As is well known, knocking that occurs in an engine causes a reduction in engine output or overheating, leading to engine destruction. This knocking has a close relationship with the ignition timing, and it is known that the engine output will be maximized if the ignition timing, that is, the ignition advance angle, is set just before the characteristic F knocking of the engine occurs. Therefore, in order to avoid knocking, if the ignition advance angle is set too low, the engine output will drop by 1 degree.

On the other hand, knocking is more likely to occur when the outside temperature is low, so it is more likely to occur throughout the year, especially in winter. Conventional ignition timing control devices of this type set the ignition timing to 1-1 to prevent knocking in the winter, so the engine output could be reduced in the summer when knocking was more likely to occur. He was able to absorb all his losses without hesitation.

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine ignition timing control device that optimally controls the engine output while preventing the occurrence of non-king.

The feature of the present invention is that the basic ignition timing toLK is determined based on the engine speed and intake air data, and the ignition timing is set as the basic ignition timing when the engine is in a steady operating state and the intake temperature exceeds a value equivalent to the outside temperature VC in summer. The ignition timing is configured to be advanced by a predetermined amount from the ignition timing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to all the drawings.

FIG. 1 shows the overall configuration of an engine control device. In the figure, 1 is an engine, the intake air necessary for combustion is measured by an air flow meter 17, and a throttle valve provided in a throttle chamber 18 is used. 19. It is taken into the engine 1 via the surge tank 12 and the intake manifold 11. Here, the air flow meter 17 has a measuring plate 48 that changes depending on the intake air flow.
A potentiometer 49 interlocked with the measuring plate 48 converts the opening degree into an electrical signal.

The signal is output to the control circuit 14.

On the other hand, fuel is fed under pressure from a fuel system (not shown), and the opening time of the fuel injection chamber 15 is controlled by a control signal from the control circuit 14, so that a predetermined amount of fuel is periodically injected into the intake manifold 7. . The air-fuel mixture introduced into the cylinder 5 is ignited at a predetermined timing by an ignition signal output from the igniter 41 to the spark plug via the distributor 42. It is exhausted to the outside through an exhaust pipe 13 via an exhaust manifold 9.

Next, various sensors will be explained. 49 is a knock sensor that detects knocking occurring in the engine, 43.4
Reference numerals 4 denote a cylinder discrimination sensor and a rotation angle sensor fixed to the shaft of the distributor 42, respectively. The cylinder discrimination sensor 43 discriminates the cylinder to be ignited and detects the top dead center position of the piston 3. The one rotation angle sensor 43 detects the engine rotation speed. 49, and outputs one pulse every predetermined rotation angle (for example, 30 degrees) of the crankshaft.

Furthermore, 45 is a water temperature sensor that detects the engine cooling water temperature.

46 is O to be careful about the residual oxygen concentration in the exhaust gas.

A sensor 47 is an intake air temperature sensor that detects the total temperature of intake air flowing into the throttle chamber 8.

The detection outputs of these various sensors are taken in by the control circuit 14vc, and based on various control programs, the ignition timing control signal and the fuel injection control signal are sent to the igniter 41. The n1 ignition timing control and fuel injection control are performed by outputting the signal to the fuel injection valve 15. Since the invention relates only to ignition timing control, other explanations will be omitted.

Next, FIG. 2 shows only the portion of the control circuit 14 relating to ignition timing control. In the figure, 50 is a read-only memory (ROM) in which fixed data and various programs are stored;
60 is a random access memory (RAM) that reads and writes various data; 70 is a microprocessor unit (MPU) that performs various arithmetic operations based on programs stored in the ROM 60;

Also, 80.82 is an input/output boat, 84 is an output port), 8
An A/D converter that converts the analog signal taken in by the 6Fi multiplexer 88 into a digital signal; 90 is a waveform shaping circuit that shapes pulsed signals from the cylinder discrimination sensor 43 and the rotation angle sensor 44; 92 is an output port 84;
The drive circuits 94, 96, and 98 amplify the signals output from the air flow meter 17 to a predetermined level, respectively.
Intake temperature sensor 47. This is a buffer amplifier that amplifies the detection output of the vehicle speed sensor 40.

Next, the processing contents of the control circuit 14 will be explained based on FIGS. 3 to 5. In FIG. 3, an initial processing program is shown. In the same figure, when the program is started by operating an ignition switch, etc. in step lOO, the registers and f engine in the input/output board 80 and 82 are processed in the first step 102. Initial setting of control data necessary for ignition timing control, etc. is performed. Furthermore, in step 104, R
The memory contents of AM60 are cleared and initial data is set. Next, in step 106, the input/output capo) 80.82
A block definition is made to the registers within. This block definition means, for example, settings such as the period for performing A/D conversion.

Furthermore, in step 108, interrupt linkage is set.

That is, when an interrupt occurs, the address of the program counter in the MPU 70 and the degenerate area of the register in the RAM 60 is specified.

Next, in step 110, permission for interrupts is made.

In step 112, the air flow meter 17. The intake air ambiguity factor Q is determined from the detection output of the rotation angle sensor 44.

Engine speed data N and intake pipe negative pressure Q/N are in ROM5
The basic ignition timing θ- is calculated by the MPU based on the program stored in the ROM 50 in the primary step 114.
It is calculated based on map data of advance angle values stored in advance. When the basic ignition timing is calculated in step 114, the process returns to step 106 and similar processing is performed.

Figure 4 shows the contents of the interrupt task that is activated at regular intervals. In the figure, when the task is activated in step 120, it is determined in the first step 122 whether flag 1 indicating that the vehicle speed is 40 fx/h or more is set. If it is determined in step 122 that "°YesS", the process moves to step 124, in which the flag is reset by 1, and in step 126, the contents of the soft counter C provided in the RAM 60 are incremented by +1. At step 128, it is determined whether the content of the soft counter C is C≧N.In other words, it is determined whether a predetermined time has elapsed since the vehicle speed reached 40 km/h or more. The interrupt task activation cycle is 50 msec.

If N=500, at step 128 the vehicle speed is 40 km.
A determination will be made as to whether the state of /h or more has continued for 25 seconds.

If the vehicle speed remains at 40/h or higher for about 25 seconds, the intake temperature detected by the intake temperature sensor 47 will be approximately equal to the outside temperature. "state".

Now, if the determination in step 128 is "Yes", the next step 130 determines whether or not the intake air temperature THA exceeds 30°C, that is, the temperature at which the intake air temperature corresponds to the outside air temperature in summer.
′ is exceeded. If the determination in step 130 is "Yes", in the next step 132 flag 2 is set indicating that the outside temperature is 30° C. or higher (summer), and the process proceeds to step 134.

and in steps 122, 128, and 130, respectively.

If the determination is "No", the process similarly moves to step 134, and in step 134, the current vehicle speed is determined to be 40 km/h.
It is determined whether or not this is the case, and if the determination is "Yes", flag 1 is set in step 136, and the execution of the task is ended in step 138.

On the other hand, if the determination in step 134 is "NO", the process moves to step 138, and the execution of the task ends at step 138.

The setting and resetting of the t-flag 1%2 is performed by searching a predetermined bit of the status register provided in the input/output port 82.

Next, FIG. 5 shows the processing contents of the ignition timing calculation interrupt task. This interrupt task is activated every time the piston 3 reaches the top dead center position. First, when a task is activated in step 140, it is determined in the fifth step 142 whether flag 2 is set.

If the determination in step 142 is NO, the process proceeds to step 146, where the ignition timing correction amount is set to Δθt o O, and the process proceeds to step 148.

On the other hand, if the determination in step 142 is "Yes", the process proceeds to step 144, where the correction amount Δθ is set to 3 degrees, and the process proceeds to step 148. In step 148, the ignition timing θ is calculated using the following equation.

θ=01+Δθ (1) Here, θSa is the basic ignition timing obtained in step 114 of the initial program.

Furthermore, in step 150, data indicating the ignition timing .theta. determined in step 148 is set in the output register provided in the output port 84. Next, in step 152, the bit corresponding to flag 2 of the status register is reset, and in step 154, the execution of the task is completely completed.

As explained above, in the present invention, the basic ignition timing is calculated based on the engine speed and intake air amount data, and when the engine is in a steady operating state and the intake temperature exceeds a value corresponding to the outside temperature in summer. Since the ignition timing tube is configured to advance the basic ignition timing by a predetermined amount, the present invention provides an ignition timing control plan for an engine that completely prevents knocking and improves engine output in summer. realizable.

[Brief explanation of the drawing]

Figure 1 is an overall configuration diagram of the engine control device, and Figure 2 is the
Figure 3 is a block diagram showing the specific configuration of the control circuit shown in Figure 5. Figure 5 shows the processing content of the ignition timing control of the control circuit shown in Figure 2, and Figure 3 shows the processing content of the initial processing program. FIG. 4 is a flowchart showing the processing contents of an interrupt task activated at regular intervals, and FIG. 5 is a flowchart showing the processing contents of the ignition timing calculation interrupt task. ]4... Control circuit, 17... Air flow meter,
40 Pa vehicle speed sensor, 41... Idanita, 43...
Cylinder discrimination sensor, 44...Rotation angle sensor, 47°゛°
Intake temperature sensor, 50-ROM, 60-RA
M, 70...MPU. Figure 2 1, Figure 3, Figure 4, Figure 5

Claims (1)

[Scope of Claims] (1) An ignition timing control device that takes in detection outputs from various sensors and controls ignition timing according to engine operating conditions through digital arithmetic processing, which includes a detection means for detecting engine rotational speed, and a throttle chamber. An air flow meter that measures the amount of intake air flowing into the engine, a vehicle speed sensor that detects vehicle speed, and an intake temperature sensor that detects intake air temperature.
The basic ignition timing is calculated based on the engine speed and intake air amount data obtained from the front engine speed detection means and the air flow meter, and the engine is in a steady operating state and the intake temperature is a value that corresponds to the outside temperature in summer. 1. An ignition timing control device for an engine, comprising: control means for advancing the ignition timing by a sufficient amount from the total basic ignition timing when the ignition timing exceeds the total basic ignition timing. (b) The control means determines that the engine is in a steady operating state when a predetermined period of time has elapsed since the vehicle speed reached 40 km/h or more.
) The ignition timing control device for the engine described in item 2. (3) The engine ignition timing control device according to claim (1), wherein the value corresponding to the outside temperature in summer is set to around 30°C.