JPH01142269A - Ignition device - Google Patents

Abstract

PURPOSE:To miniaturize ignition parts and obtain a low-cost ignition device by making two ignition plugs which are connected to the secondary winding of a simultaneous ignition coil simultaneously carry out spark discharge. CONSTITUTION:When an engine is rotated, a control circuit 2 outputs an ignition signal to power transistors 3, 4 according to an ignition order while cutting off the ignition signals at a defined timing. As one power transistor 3 is turned off, a high voltage is generated on the secondary side of a simultaneous ignition coil 5 causing ignition plugs 7, 8 to carry out spark discharge. Also, a mono- multi 6 is operated to feed a switching signal to a switching transistor 12. As a result, a DC high voltage power source 11 is operated to charge capacitors 16, 17, with a high voltage, thereby, allowing the ignition plugs 7, 8 to continue spark discharge. At this time, no current is fed to the other ignition plugs 9, 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition system for an internal combustion engine, and more particularly to a distributorless ignition system using a simultaneous ignition coil.

(Prior art) Conventionally, long discharge and high energy in a distributorless ignition system is described in Japanese Patent Application Laid-Open No. 61-218773, but this method uses an independent ignition coil for each spark plug. However, no particular consideration was given to a simultaneous ignition method in which two spark plugs are ignited at the same time.

[Problem that the invention seeks to solve]

The above conventional technology does not take into account the simultaneous ignition system, and only has the function of supplying voltage from the second power source to the spark plug connected to the negative terminal of the secondary winding of the simultaneous ignition coil. It did not have the function of supplying voltage from the second power source to the spark plug connected to the positive terminal, which is generated by this method.

An object of the present invention is to provide an inexpensive ignition system ignition device with miniaturized ignition parts by a simultaneous ignition type distributor-less ignition device in which two spark plugs connected to a simultaneous ignition coil discharge sparks at the same time. be.

[Means for solving problems]

The above problem is the first problem when the negative electrode is grounded? i! source and the first
One end of the primary winding is connected to the positive pole of the power supply, the other end is grounded through a switching element, both terminals of the secondary winding are connected through two spark plugs arranged in series, and the two a simultaneous ignition coil formed by grounding the connecting portions of the ignition plugs; a control circuit that outputs an ignition signal to the switching element at a predetermined timing; and a pulse oscillation circuit that outputs a switching signal in synchronization with the ignition signal. , and a second power source that supplies voltage to both terminals of the secondary winding of the simultaneous ignition coil according to the switching signal.

[Effect]

The control circuit causes two spark plugs connected to the secondary winding of the ignition coil to simultaneously discharge sparks at a predetermined timing, and the pulse oscillation circuit generates a switching signal in synchronization with the predetermined timing. The second power supply supplies a continuous voltage to the secondary winding of the co-ignition coil according to the switching signal.

〔Example〕

Hereinafter, a lower embodiment of the present invention will be explained with reference to FIG. 1st
The figure shows an embodiment in which the present embodiment is applied to a four-cylinder engine, and a simultaneous ignition coil 5, which is formed by integrally molding two ignition coils, is provided for spark plugs 7 to 1o. The first power supply 1 supplies power to this simultaneous ignition coil 5 . Further, the control circuit 2 mainly composed of a microcomputer is in charge of controlling the energization of the simultaneous ignition coil 5, and the ignition signal is sent to the power transistor 3, 4, thereby controlling the timing of starting and cutting off the primary coil current of the simultaneous ignition coil 5.

Next, a DC high voltage power supply 11 consisting of a DC-DC converter includes a switching transistor 12, a step-up transformer 13,
Consisting of diodes 14, 15 and capacitors 16 and 17, a signal synchronized with the ignition signal given to the power transistors 3 and 4 by the control circuit 2 is given to the switching transistor 12 by a monomulti (monostable multivibrator) 6, and this signal switching transistor 1
2 turns on and off, and this causes boosting 1-2 of lance 13.
Next, a high voltage pulse is generated in the coil, and the diode 14.1
5 to generate a high voltage (several KV) DC voltage with the polarity shown between the terminals of the capacitors 16 and 17.

Next, the operation of this embodiment as a whole will be explained.

When the engine rotates, the control circuit 2 outputs an ignition signal to each power transistor 3, 4 according to the ignition order, and cuts off the ignition signal at the ignition timing.

Therefore, if the power transistor 3 is turned off at a certain timing according to the ignition order, a high voltage is generated on the secondary side of the simultaneous ignition coil 5, and the spark plug 7.
8 produces a spark discharge. On the other hand, the monomulti 6 operates at the timing when the power transistor 3 is turned off, and supplies a switching signal for a certain specified time to the switching transistor 12.

As a result, the DC high voltage power supply 11 operates, and the capacitor 1
Since the spark plug 6.17 is charged with a high voltage, the spark plug 7.8, which has started spark discharge with the output voltage of the simultaneous ignition coil 5, is subsequently supplied with a discharge current from the DC high voltage power source 11.
Even after the output of the simultaneous ignition coil 5 disappears, the discharge continues, and high ignition energy is generated due to the long time discharge.

Then, when the rectangular wave signal from the monomulti 6 disappears, the DC high voltage power supply 11 stops operating, and as a result, the spark plug 7
．． 8 also stops.

On the other hand, when the DC high voltage power supply 11 is operating in this way, its output is also applied to the other spark plugs 9, 10, but at this time, the spark plugs 7. Since the discharge voltage of spark plug 8 is lower than the discharge voltage of other spark plugs 9 and 10, no current flows to the other spark plugs, and the discharge current from the DC high-voltage power supply 11 is guaranteed only to the spark plug that is discharging. will be supplied.

Hereinafter, the ignition timing of the ignition plugs 9, 10 operates in the same manner, and when the ignition plugs 9, 10 start discharging due to the output of the simultaneous ignition coil 5, the DC high voltage power supply 11 operates for a specified time, Supply discharge current only to that spark plug. Note that, after discharging by the output of such an ignition coil, a discharge current is subsequently supplied from another power source for a predetermined period of time to sustain the discharge, which is called superposition discharge.

FIG. 2(a) shows a normal discharge current waveform using only the ignition coil, and FIG. 2(b) shows a discharge current waveform in the case of superimposed discharge according to the above embodiment.

τ indicates the superimposed DC power supply voltage operating time.

〔Effect of the invention〕

According to the present invention, since it is possible to simultaneously discharge sparks to two spark plugs connected to the secondary winding of a simultaneous ignition coil, it is possible to downsize the ignition parts and provide an inexpensive ignition system.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram of an embodiment of the present invention, and FIG.
The figure is a diagram showing a discharge current waveform. DESCRIPTION OF SYMBOLS 1...First power source, 2...Control circuit, 5...Simultaneous ignition coil, 6...Mono multi, 7-1o...Spark plug. 11...DC high voltage power supply.

Claims (1)

[Claims] 1. A first power supply whose negative terminal is grounded; 1 connected to the positive terminal of the first power supply;
One end of the secondary winding is connected, the other end is grounded through a switching element, and both terminals of the secondary winding are connected through two spark plugs arranged in series. a simultaneous ignition coil whose connecting portion is grounded; a control circuit that outputs an ignition signal to the switching element at a predetermined timing; a pulse oscillation circuit that outputs a switching signal in synchronization with the ignition signal; Therefore, the ignition device is characterized by comprising: a second power source that supplies voltage to both terminals of the secondary winding of the simultaneous ignition coil.