JPH0756251B2 - Internal combustion engine ignition device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an internal combustion engine ignition device that performs ignition timing control using a microcomputer.

[Conventional technology]

Conventionally, there is an internal combustion engine ignition device of this type shown in FIG. In the figure, 1 is a magneto coil of a magneto generator driven by an internal combustion engine (hereinafter referred to as engine) not shown, 2 is a diode for rectifying the power output of the power coil 1, and 3 is charged by the rectified output of the diode 2. It is a capacitor to be used. Reference numerals 4 and 5 denote diodes connected between both ends of the power generation coil 1 and ground, 6 denotes a power supply circuit connected to one end of the power generation coil 1, and 7 denotes connection between a connection point between the diode 2 and the capacitor 3 and ground. The thyristor receives the ignition signal of the ignition timing control circuit 13 described later at the ignition timing of the engine and transfers the charge stored in the capacitor 3 to the ignition coil.
It is to discharge to 10. Further, 8 is a resistor provided between the gate of the thyristor 7 and the ground, and 9 is a capacitor 3
Is a diode for the back electromotive force side path of the primary coil of the ignition coil 10 provided between the connection point of the ignition coil 10 and the ground, and the ignition circuit 11 is constituted by these diodes 2 to 9. There is. The secondary winding of the ignition coil 10 is grounded via the ignition plug 12.

The ignition timing control circuit 13 receives a waveform shaping circuit 15 that inputs an output signal of a signal coil 14 that generates an ignition signal in synchronization with the rotation of the engine and an output of the waveform shaping circuit 15 via an input interface 16. Microcomputer 17 to insert,
It is composed of an output interface 18 for supplying the output of the microcomputer 176 to the gate of the thyristor 7 of the ignition circuit 11. Also, these waveform shaping circuits
15 to the output interface 18 are connected to the power supply circuit 6 and grounded so that the power from the power supply circuit 6 is supplied.

Next, the operation of the internal combustion engine ignition device configured as described above will be described. The power generation output of the power generation coil 1 is the diode 2
Is rectified by and charges the capacitor 3. An ignition signal corresponding to the rotation of the engine is output from the signal coil 14, and the ignition signal is waveform-shaped by the waveform shaping circuit 15 and then input to the micro computer through the input interface 16.
Entered in 17. The microcomputer 17 calculates a predetermined ignition timing based on this signal and supplies the ignition signal to the gate of the thyristor 7 via the output interface 18. As a result, the thyristor 7 becomes conductive, and the charge of the capacitor 3 passes through the thyristor 7 and the ignition coil 10
Is discharged to the primary coil. As a result, a secondary voltage is generated in the secondary coil of the ignition coil 10, and spark discharge is generated in the spark plug 12. In this way, the charge stored in the capacitor 3 is discharged according to the ignition timing of the engine, and spark discharge is generated in the spark plug 12 to operate the engine.

[Problems to be solved by the invention]

The conventional internal combustion engine ignition device is configured as described above, but since the microcomputer 17 operates at high speed, it is very susceptible to noise. Since the spark discharge at the spark plug 12 is originally a noise source, the microcomputer 17 has a problem that it malfunctions due to this noise. Therefore, conventionally, the ignition circuit 11 and the ignition timing control circuit 13 are divided,
By storing these in separate cases, the malfunction of the micro computer 17 due to noise was prevented. However, such a method has a problem that it requires separate cases, is costly, and is extremely disadvantageous in terms of space.

The present invention has been made to solve the above problems, and a circuit and a microcomputer that cannot suppress noise due to the influence of spark discharge can be housed in an integrated case, which can be miniaturized and reduced in size. An object is to obtain a cost-effective internal combustion engine ignition device.

[Means for solving problems]

An internal combustion engine ignition device according to the present invention includes a noise removal filter provided on a signal line that connects a waveform shaping circuit, an input interface, a microcomputer, an output interface, and an ignition circuit, and a noise removal filter, an input interface, Connects the power supply lines for the input interface, microcomputer, and output interface to the ground separation coil provided between the common ground line connecting the ground lines for the microcomputer and output interface and the ground point of the other circuit. The power supply separation coil is provided between the common power supply line and the power supply line of another circuit.

[Work]

In the present invention, noise generated by the spark discharge is absorbed by the filter, so that malfunction of the microcomputer is prevented. Further, since the ground line is common, it is cut off from the voltage fluctuation of the noise source. Furthermore, by separating the common ground wire of the computer and the filter on the input / output side of this computer from the ground potential of the other circuit by a coil, even if the ground potential of the other circuit fluctuates due to noise, etc. The influence on the microcomputer by is canceled by the coil.

〔Example〕

FIG. 1 is a circuit diagram of an internal combustion engine ignition device according to an embodiment of the present invention. In the figure, 1 to 18 are the same as those of the conventional device of FIG. 19, 20 are coils as a power source separation coil, 21 is a capacitor, and these constitute a low frequency filter, and are provided in a power supply path from the power supply circuit 5 to the input interface 16, the microcomputer 17 and the output interface 18. Has been. 22a to 22c are resistors connected between the waveform shaping circuit 15 and the input interface 16, and 23a to 23c.
Are capacitors connected in parallel to these resistors 22a to 22c, respectively, and each constitutes a CR filter. 24a to 24c
Reference numerals 25a to 25c are resistors and capacitors which similarly form a CR filter, and are connected between the input interface 16 and the micro computer 17. Further, on the output side of the micro computer 17, a filter including a resistor 26 and a capacitor 27 is provided between the output interface 18 and the output interface 18, and the output interface 18 and the thyristor 7 are connected.
A filter including a resistor 28 and a capacitor 29 is provided between the two. The ground of each of the above filters and the ground of the input interface 16, the micro computer 17, and the output interface 18 are connected to a common ground wire 30. Connected to circuit 15 ground.

In the internal combustion engine ignition device configured as described above, the normal ignition operation is the same as that of the conventional device, and thus the description thereof is omitted here. The noise from the power supply circuit 5 side is the coil 1
Absorbed by a filter consisting of 9,20 and condenser 21,
The noise from the signal line is not input to the input interface 16, the micro computer 17, and the output interface 18, and the noise from the signal line is not included in the resistors 22a to 22c and the capacitor.
Noise from the input side of the micro computer 17 is absorbed by the filter composed of 23a to 23c and the filter composed of the resistors 24a to 24c and the capacitors 25a to 25c, and the noise from the output side of the micro computer 17 is absorbed by the resistor 28 and the capacitor 29. Is absorbed by the filter composed of and the filter composed of the resistor 26 and the capacitor 27. Then, each filter and the input interface 16 to the output interface 18 are connected by a common ground wire 30, and this common ground wire 30 and
The waveform shaping circuit 15, which is the ground potential of the device, the power supply circuit 6, the diodes 4, 5 and 9, the thyristor 7, and the ground side potential of the resistor 8 are separated by the coil 31. Even if it fluctuates, it is not affected by this.
Therefore, noise due to spark discharge or the like is not input and output to the output interfaces 16 and 18 and the micro computer 17, and malfunction of the micro computer 17 is prevented. As a result, there is no need to divide the ignition circuit and the ignition timing control circuit into separate cases as in the conventional case, and the entire circuit can be accommodated in one case 32.

〔The invention's effect〕

As described above, according to the internal combustion engine ignition device of the present invention, noise from the input / output signals of the input interface, the microcomputer, and the output interface can be removed, and the influence of the fluctuation of the ground potential of the device or the fluctuation of the power supply can be minimized. Since it does not affect the computer, an ignition circuit that easily generates high-frequency noise and a microcomputer that is particularly prone to malfunction due to high-frequency noise because high-speed arithmetic processing is required can be housed in one case, and a small and inexpensive internal combustion engine There is an effect that the ignition device can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an internal combustion engine ignition device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional internal combustion engine ignition device. 1 ... Generating coil, 3 ... Capacitor, 7 ... Thyristor, 10 ... Ignition coil, 11 ... Ignition circuit, 12 ... Ignition plug, 13 ... Ignition timing control circuit, 14 ... Signal coil, 17
...... Microcomputer, 19,20,31 …… Coil, 21,2
3a ~ 23c, 25a ~ 25c, 27, 29 ... capacitors, 22a ~ 22c, 24a
~ 24c, 26, 28 …… resistance, 30 …… signal line. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A magneto coil of a magnet generator, an ignition circuit for generating an engine ignition voltage of the ignition coil at a predetermined ignition timing by the output of the magneto coil, and an ignition plug connected to the ignition coil for igniting the engine. A signal coil for generating an ignition signal in synchronization with the rotation of the engine; a waveform shaping circuit for shaping the output signal of the signal coil; and an input interface for receiving the output signal of the waveform shaping circuit to a microcomputer. A microcomputer that calculates an ignition timing of the ignition circuit based on a signal from the input interface and outputs the calculation result, an output interface that receives the calculation result and transmits the result to the ignition circuit, the waveform shaping circuit, The input interface, the microcomputer, the output interface, and A noise removing filter provided on a signal line connecting each of the ignition circuits, a common ground line connecting the noise removing filter, the input interface, the microcomputer, and the output interface with each other, and another circuit. Between a common power supply line connecting the power supply lines of the input interface, the microcomputer, and the output interface, and a power supply line of another circuit, and a grounding coil provided between the power supply line of the input interface, the microcomputer, and the output interface. A power source separation coil, the ignition circuit, the waveform shaping circuit, the input interface, the microcomputer, the output interface, the noise removal filter,
An ignition device for an internal combustion engine, comprising: a case for accommodating an earth separation coil and a power supply separation coil.