JPS59126071A - Ignition timing control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make expensive crank angle sensor as well as an ignition timing measuring counter unnecessary and reduce the cost of the device by a method wherein an ignition signal is outputted by operating an absolute time till the optimum ignition timing after detecting a reference crank angle position. CONSTITUTION:When a contact point 4 is opened at every moment in which a piston passes a position located at 90 deg. before the upper dead point thereof, a transistor 6 is put ON upon every opening motions thereof and an output is generated from a monostable multivibrator 7 for a predetermined period of time to input the detecting signal A of the reference crank angle position into a control unit 3. The output of the monostable multivibrator 7 serves also as the detecting signal of the revolving number of the engine and the optimum ignition timing is obtained in the unit 3 based on both of the outputs of the monostable multivibrator and a load sensor 1. The unit 3 operates the absolute time from said reference crank angle position to the optimum ignition timing to set a timer and outputs the ignition signal B to an ignition coil 19 through a driver circuit 11 when the set time is elapsed after inputting the signal from the monostable multivibrator 7.

Description

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

Conventionally, when controlling the ignition timing of an internal combustion engine electronically, detection signals of the reference crank angle position (for example, the position corresponding to piston top dead center) and the crank angle position that changes from moment to moment are used to determine the optimum ignition timing. Looking for ignition timing.

That is, the ignition timing is controlled so that the crank angle position detection signal is counted by a counter from the time when the reference crank angle position detection signal is output, the crank angle position corresponding to the optimum ignition timing is detected, and the ignition signal is output.

However, in such a conventional ignition timing control device, a crank angle sensor is required to detect the reference crank angle position and the crank angle position that changes from time to time. Since a counter is required for this purpose, there is a problem in that the cost is high.

The present invention has been made in view of the above-mentioned circumstances, and has a configuration in which the ignition timing is timer-controlled by detecting one reference crank angle position and setting the interval from this crank angle position to the optimum ignition timing using an absolute time. In particular, it is an object of the present invention to provide an ignition timing control device that is lower in cost than conventional ones.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

In FIG. 1, a load sensor 1 is comprised of a variable resistor whose resistance value changes depending on the degree of accelerator opening, for example. The load signal from the load sensor 1 is digitized by an A/D converter 2 and input to a controller unit 3. Reference numeral 4 denotes a contact point built into the distributor, which is configured to always open at a constant crank angle position, and is used to detect the reference crank angle position and also to detect the engine speed. The opening operation position of this contact point 4 is a crank angle position that is further advanced than the maximum advance value of the ignition range used during engine operation, for example, 90 degrees before piston top dead center (hereinafter referred to as BTDC).
90°).

5 is a signal processing circuit that generates signals of the reference crank angle position and engine speed according to the opening operation of the contact point 4;
The transistor 6 has an input terminal connected to the collector side of the transistor 6, and a one-shot multipipe rake T whose output terminal is connected to the control unit 3. 8, 9, and 10 are fixed resistances.

Then, the control unit 3 reads out the optimum ignition timing corresponding to the operating condition based on the signals from the load sensor 1 and the contact point 4 from the data of the ignition timing characteristics inputted in advance. The absolute time from the reference crank position to the optimum ignition timing is calculated and set in a timer, and an ignition signal is output at the optimum ignition timing.

Reference numeral 11 denotes a driver circuit which cuts off the primary current supplied from the battery of the ignition coil 19 when the ignition signal is output from the control unit 3, and a PNP type transistor 12 which turns on and off according to the output of the control unit 3. The base is connected to the collector side of this transistor 12, and the ON/O of the transistor 12 is controlled.
It includes an NPN type transistor 13 that turns on and off in synchronization with the FF. 14 is a Zener diode, 15
．． 16, 17, and 18 are fixed resistances.

Next, the action will be explained.

The contact point 4 opens every time the crank angle position reaches 90° BTDC, regardless of the operating state. Each time this opening operation is performed, the transistor 6 is momentarily turned on, a trigger pulse is input to the one-shot multi-pipe rake T, and the multi-vibrator T also generates an output for a predetermined period of time, causing the control unit 3 to receive a signal as shown in FIG. A detection signal of a reference crank angle position is input. Moreover, the output signal of this one-shot multi-pipe rake 7 also serves as a detection signal of the engine rotation speed, and in the control unit 3,
Based on this detection signal and the load signal input from the load sensor 1 via the A/D converter 2, the optimum ignition timing corresponding to the current operating condition is determined, and the optimum ignition timing is calculated from the reference crank angle position to the optimum ignition timing. The absolute time (indicated by T in FIG. 2 (J3)) is calculated, and the timer is set based on the result of this calculation.

After the timer setting time has elapsed since the signal from the one-shot multivibrator T was input, the control unit 3 outputs an ignition signal (FIG. 2(B)).

That is, by controlling the absolute time T according to the operating condition, the ignition timing is optimally controlled. When this ignition signal is output, the transistor 12 is turned off, the other transistor 13 is also turned off, and the ignition coil 1 is turned off.
The primary current of 9 is cut off, a high voltage is generated on the secondary side, and ignition is performed.

In this way, the opening timing of contact point 4 is fixed and the opening signal is used as a reference signal, and the time setting from this reference position to the optimum ignition timing is controlled by a timer using absolute time, which is different from the conventional method. This eliminates the need for an expensive rank angle sensor and a counter that measures the crank angle from the reference position to the ignition timing, thereby reducing costs.

Incidentally, re-ignition control can also be performed by similarly setting an appropriate dwell time.

As described above, the present invention eliminates the need for an expensive rank angle sensor that detects both the reference crank angle position and the crank angle position that changes as the engine rotates.
To provide a low-cost ignition timing control device since the measurement from the reference crank angle position to the ignition timing is controlled by a timer using absolute time, thereby eliminating the need for a counter for measuring ignition timing, which was conventionally necessary. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG.
F]) respectively show time charts of the detection signal of the reference crank angle position and the ignition signal. 1...Load sensor 2...A/D converter 3.
...Control unit 4...Contact point 5...Signal processing circuit 11...Driver circuit 19...Ignition coil patent Applicant Fujio Sasashima, patent attorney, Japan Electronics Co., Ltd.

Claims (1)

[Claims] In an ignition timing control device for an internal combustion engine that controls ignition to occur at an optimal ignition timing corresponding to the operating state of the internal combustion engine, a detection means for detecting and outputting a reference crank angle position;
An ignition timing control device for an internal combustion engine, comprising: a control means for calculating an absolute time from the output of the detection means to the optimum ignition timing and outputting a large point signal.