JPS58217769A - Control circuit for ignition of engine - Google Patents

Abstract

PURPOSE:To enable to fix the time of current supply to an ignition coil constant with high accuracy even if the engine speed is changed abruptly, by controlling the time of current supply by detecting the engine speed at each instant. CONSTITUTION:A velocity signal generating circuit 11 furnished with crankangle pulses KP as an input signal produces a velocity signal B having a level corresponding to the engine speed, and the velocity signal B is integrated by a resistor 12 and a capacitor 13. The capacitor 13 is made to discharge by a transistor 15 which is controlled by an ignition timing signal A. Further, a function generating circuit 17 produces a function signal D that is varied with time and cleared each time the ignition timing signal A is produced. A current supply starting signal is produced by making comparison between the function signal D and a velocity integrated signal C by a comparator 18. With such an arrangement, it is enabled to keep the time of current supply to the ignition coil constant with high accuracy even if the engine speed is changed abruptly.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine ignition control circuit, and particularly to control of energization time of an ignition signal that drives an ignition coil.

In recent years, with the rapid development of electronic technology, engine ignition control has also been electronically controlled. In this case, the objects to be controlled in engine ignition control are broadly divided into ignition timing control and energization time control. Ignition timing is controlled by rotating speed,
It controls the optimal ignition timing in response to ambient conditions such as negative pressure, water temperature, and atmospheric pressure, and also controls the energization time so that it always energizes for a fixed period of time regardless of the rotation speed. It is something to do.

In conventional electronically controlled engine ignition control circuits, the crank angle pulse generated for each unit angular rotation of the crankshaft and the reference position nozzle indicating the reference position of the crankshaft are used. is input into a microcomputer, the crank angle pulses are counted based on this reference position and the time point at which e-rus occurs, and at the time when this counted value is calculated based on the rotational speed one revolution before, the ignition coil is turned on. Through this control, the energization time and ignition timing are controlled.

In this case, since the control range of the ignition timing is relatively narrow, sufficient control accuracy can be obtained by setting the reference position within the control range. However, is there a restriction on power-on time? Since KJ is a control that is intended to be constant over the entire rotation range of the engine, its control range is extremely wide. For this reason, if the energization time is controlled using data from one revolution before, there is a major problem in that the accuracy during rotation fluctuations such as during sudden acceleration is significantly reduced.

Therefore, an object of the present invention is to provide an engine ignition control circuit that can perform highly accurate energization time control even when rotational fluctuations occur.

In order to achieve these objects, the present invention is to: - detect the rotation of the engine in real time and control the energization time; Hereinafter, the engine ignition control circuit according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment of an engine ignition control circuit according to the present invention. In the figure, reference position sensors 1 are provided close to the outer periphery of a reference position rotor 3 mounted on the crankshaft 2 of the engine, and are spaced 180 degrees apart from each other on the outer periphery of the reference position rotor 3. The passage of the protrusion 4, which is disposed in the same direction, is magnetically detected. and,
The protrusion 4 of the reference position rotor 3 represents the piston position of the engine, and the reference position sensor 1 is configured to detect the protrusion 4 at about 10 degrees before the top dead center TDO of the piston. It is positioned. Reference numeral 5 denotes a crank angle sensor, which is installed close to the outer periphery of the crank angle rotor 6 mounted on the crankshaft 2.
An output is generated by magnetically detecting the passage of the teeth 7 provided at a pitch. 8 is a waveform shaping circuit that sends out a reference position pulse RP by shaping the output signal generated from the reference position sensor 1; Pituchi crank angle
This is a waveform shaping circuit that generates the ξ pulse KP. 10 is an ignition timing control circuit which generates an ignition timing signal by inputting and calculating a negative pressure signal, a water temperature signal, an air pressure signal, a reference position nozzle RP and a crank angle pulse KP; 11 is a crank angle nozzle; A speed signal generation circuit that receives KP as an input and generates a speed signal B at a level corresponding to the rotational speed; 12.13 is a resistor and a capacitor that constitute an integrating circuit that integrates the speed signal B supplied via the diode 14; Reference numeral 15 denotes a transistor which is turned on when the ignition timing signal is generated and discharges the photoelectric charge of the capacitor 13, thereby setting the starting point of the integral operation. These speed signal generation circuits 11. resistance 1
The integration circuit constituted by 2 and the capacitor v13 and the transistor 15 constitute an arithmetic circuit 16 that generates a rotational speed integral signal 0 that increases in proportion to the rotational speed. Reference numeral 17 denotes a function generating circuit that is cleared every time the ignition timing signal A is generated and generates a function signal that changes over time. Then, for example, as shown in FIG. 2, the function generating circuit 17 calculates, for example, an energization time of 5 m5ec for graphs a1 to a5 that increase in accordance with the rotation of the engine.
It is configured to generate a function of graph b connecting points at which energization is started, and a read-only memory or the like is used. 18 is a comparator which takes the speed integral signal C as a positive input and the function signal C as a negative input; 19 is a differentiating circuit for differentiating the output of the converter 18; 20 is set by the output of the differentiating circuit 19; Ignition timing signal A flip-flop circuit reset by a person, whose set output Q
is supplied as an ignition control signal X to a transistor (not shown) for driving an ignition coil (not shown).

In the circuit configured in this way, when the engine is rotating, the three reference position rotors attached to the crankshaft 2 are rotating, and the reference position sensor 1 is at this reference position. The passage of a protrusion 4 provided on the outer periphery of the rotor 3 is detected and its output is changed. The output of this reference position sensor 1 is generated as a reference position pulse RP shown in FIG. 3(,) via a waveform shaping circuit 8.

On the other hand, the crank angle sensor 5 also detects the passage of the teeth 7 provided on the outer periphery of the crank angle rotor 6 and changes its output.

The output of the crank angle sensor 5 is then passed through a waveform shaping circuit 9 into a crank angle pulse K as a periodic signal corresponding to the rotation of the engine as shown in FIG. 3(b).
It is generated as P. The ignition timing control circuit 10 calculates the next ignition timing based on the reference position, data from the previous cycle of orus RP, the negative pressure signal, the water temperature signal, and the atmospheric pressure signal, and the count value of the crank angle census KP corresponds to the calculated value. At the point in time corresponding to the value, the ignition timing signal person turns on the ignition timing signal in Fig. 3 (C
) is generated as shown in 11 speed signal generation circuits,
When the crank angle pulse KP is supplied, a speed signal B corresponding to its frequency, that is, corresponding to the rotation speed, is generated, and this speed signal B is passed through a diode 14 to a resistor 1.
2 and a capacitor 13. In this case, since the transistor 15 which is turned on by the ignition timing signal is provided between both ends of the capacitor 13, integration is started every time the ignition timing signal A is generated. Therefore, a speed integral signal C, which is obtained by integrating the speed signal B every time the ignition timing signal A is generated, is outputted from the arithmetic circuit 16 in a sawtooth shape as shown in FIG. 3(d).

On the other hand, the function generating circuit 17 generates a function signal shown in FIG. 2 which is cleared every time the ignition timing signal A is generated and changes over time. This function signal always changes at a constant rate regardless of the rotational speed of the engine, and the changes in each ignition cycle are as shown in FIG. 3 fd).

Then, the controller 18 compares the speed integral signal C and the function signal R, and when the speed integral signal C exceeds the function signal R, the output of the controller 18 is reversed from "L" to @H. This output change is differentiated in the differentiating circuit 19 and outputted as shown in FIG. 3(e). Since the output signal of the differentiating circuit 19 is supplied to the set terminal SK of the flip-flop circuit 20, the flip-flop circuit 20 is set, and the ignition control signal X generated from the set output terminal Q is transmitted as shown in FIG. f) becomes “H”. When the ignition side (supply) signal , when the next ignition timing signal A is generated, the flip-flop circuit 20 is reset and the ignition control signal When the timing signal A is generated, the transistor 15 is turned on, rapidly discharging the charge in the capacitor 13, restarting the integration operation of the speed signal B, and clearing the function generation circuit 17, which changes over time. Regenerate the function signal.

By sequentially performing such operations, ignition control is performed in which the set period of one flip-flop circuit 20 is set as the energization time.

In this case, since rotation detection and control are performed in real time to control the energization time to a predetermined constant value at each rotation speed, A highly accurate energization time control system can be used even during fluctuations.

In the above embodiment, a case has been described in which the analog circuit is used. However, in the case of digital processing, the inside of the arithmetic circuit 16 is configured to count the crank angle nozzle KP as shown in FIG. The function generating circuit 17 is configured by a counter 21 that outputs an ignition timing signal and is reset by the operator.
The flip-flop circuit 20 can be set using the output of a digital comparator 18' which compares the output signal C' of the counter 21 with the output signal D'.

As explained above, the engine ignition control circuit according to the present invention detects the engine rotation speed in real time and controls the energization time, so even if the engine rotation speed suddenly changes, the ignition coil This has the excellent effect of making it possible to keep the energization time constant with high precision.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the engine ignition control circuit according to the present invention, FIG. 2 is a graph showing the characteristics of the function generating circuit shown in FIG. 1, and FIG. FIG. 4 is a circuit diagram showing another embodiment. 1... Reference position sensor, 3... Reference position rotor, 5
... Crank angle sensor, 6... Crank angle rotor, 8, 9... Waveform shaping circuit, 10... Ignition timing side circuit, 11... Speed signal generation circuit, 1
2...i anti-%1.3...capacitor, 15...transistor, 16...arithmetic circuit, 17...function generation circuit, L8, l8'...converter, 1
9... Differential circuit, 20... Flip-flop circuit,
21...Counter.

Claims (1)

[Claims] (1) A reference position sensor that generates a reference position nozzle indicating the engine position, a crank angle sensor that detects engine rotation and generates a crank angle nozzle for each unit angular rotation, and the reference position an ignition timing control circuit that receives a nozzle and the crank angle nozzle as input and generates an ignition timing signal; and an arithmetic circuit that generates a speed integral signal that integrates the rotational speed of the engine while being cleared by the ignition timing signal. a function generation circuit that is reset by the ignition timing signal and generates a function signal that changes over time; a controller that detects that the output of the arithmetic circuit exceeds the output value of the function generation circuit; a flip-flop circuit set by the output of the comparator and cleared by the ignition timing signal;
An engine ignition control circuit characterized in that the set period of this fritz flop circuit is supplied as an energization period signal to a transistor for driving an ignition coil.