JPS5810163A - Igniting apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To enable to prevent occurrence of accidents due to short-circuiting of a diode in an igniting apparatus utilizing a semiconductor rectifying circuit, by detecting a trouble of a diode through detection of the change in the direction of current flow, and disconnecting an operating circuit when the change in the direction of current flow is detected. CONSTITUTION:In case that an operating circuit is constituted by a diode D1, ignition plugs P1, P2 and a diode D4, current is passed from D4 P4 P1 D1. When the polarity of the voltage produced by an ignition coil 2 is reversed, current is passed from D2 P2 P3 D3. Here, if a diode D2 causes a trouble of short-circuiting, current is passed reversely through the circuit of the diode D2 and the ignition plug P2 when diodes D1, D4 and ignition plugs P1, P4 are in operation. This reverse current induces a negative voltage in a detecting coil S2 and a control circuit 10 detects occurrence of a trouble from the negative voltage. Then, the control circuit 10 operates to prevent occurrence of an accident by opening an emergency cut-off switch W2 and thereby stopping operation of the ignition plugs P2, P3. Here, since only the ignition plugs P1, P2 are operated in this state, rapid stopping of an automobile is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition device for an internal combustion engine using a semiconductor rectifier.

As shown in FIG. 1, a conventional ignition system for an internal combustion engine with a mechanical power distribution mechanism supplies the voltage of a battery 6 to an ignition coil 2 via a switch 7 and an igniter amplifier 4.
The secondary voltage obtained from the ignition coil 2 is applied as a secondary voltage to the PI using the distributor 1.
Power was distributed to each spark plug 3 of ~P and ignited.

Note that 5 is an ignition signal generator.

However, with the introduction of a contactless system to reduce spark noise during power distribution from the distributor 1, and the introduction of a control circuit using a microcomputer on the primary side of the ignition coil of the ignition system, internal combustion engine manufacturers An ignition device that uses a semiconductor rectifier in the secondary circuit instead of the distributor of the type power distribution mechanism is being considered.

FIG. 2 shows a schematic circuit of an ignition system for a four-cylinder automobile engine using a semiconductor rectifier (hereinafter abbreviated as a diode).

In the circuit of FIG. 2, it has been confirmed that the instantaneous overvoltage applied to each diode 8 of the distributor-less ignition coil 2, ~D, reaches 40 to 50 KVp. This can easily occur due to wear of the discharge terminals of the ignition plaque when the engine is started.

Therefore, in the conventional ignition system of this kind, the transient peak rated voltage of the diodes D1 to D4 is required to have a performance of 50 KVP or more, and two to three diodes 8 are connected in series as shown in Fig. 3. , a structure that obtains a transient peak rated voltage of 50KVP or more is adopted. However, consolidating the diodes 8 into one as shown in Figure 2 is a path to technological progress, and in this case, considering the possibility of overvoltage operation as described above, protective measures should be taken in the event of a diode failure. is necessary.

The most serious and dangerous failure of the diode 8 is the Kuyot phenomenon caused by deterioration of the reverse breakdown voltage characteristics of the diode 8. In the short-circuited diode 8, the secondary high voltage generated from the ignition coil 2 shown in FIG. Ignition will re-ignite the remaining gases from combustion, and the energy of the combustion will be released into the exhaust pipe, causing damage to the exhaust pipe, exhaust gas purification system, and muffler.

In addition, the ignition during the compression process occurs when the piston is still near the bottom dead center, so the intake pulp is not completely closed.
The energy of combustion will be released towards the vaporizer. There is also fuel leakage in the carburetor, which is extremely dangerous and could cause a fire.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition device for an internal combustion engine that includes a detection section that detects a failure of a diode in order to prevent the above-mentioned dangers.

The ignition device of the present invention focuses on the fact that when the ignition plug ignites with the high voltage supplied from the ignition coil, the direction of the current in the operating circuit is always constant if the diode is normal. ing.

That is, in the circuit of FIG. 2, when the operating circuit is composed of diode D11 spark plug PI% spark plug P&, diode D, the current is D4→P4→P,→D
It flows in the order of I. Next, when the voltage generated by the ignition coil 2 becomes reverse polarity, the operating circuit changes to the diode D3.
, spark plug PM, spark plug P3% diode D, and current flows in the order of →P, →P, →D. The current flow order D4→P, →P, →D1%, →P2→P, →D always remains unchanged as long as the diode 8 is normal. However, the rectifying direction of the diode 8 determines the order in which the current flows and the order in which the spark plugs 3 fire.

However, if diode D2 has failed and lost its reverse voltage characteristics and is in a short-circuit state, then diode DI,
D4, spark plug P r , P 4 circuit is in operation, diode D shorted.

And a current flows through the spark plug P2 in the opposite direction to that in the normal operating state.

The present invention is characterized in that a diode failure is detected by detecting a change in the direction of this current, and a circuit operating due to the diode failure is disconnected.

FIG. 4 shows an ignition device for an internal combustion engine including a diode failure detection section according to an embodiment of the present invention.

The ignition device according to the present invention is mainly composed of the following parts.

That is, D1 generates high voltages with alternately reversed polarities.
A distributorless ignition coil 2 having diodes 8 of ~D, and a spark generating circuit P, -
The spark plugs 3 of P, constitute an ignition section, each coil 9 of 81 to 'S4 detects the direction of high voltage current, a control circuit 10 determines the direction of the detected current, and a control circuit 10 in the event of a failure. A diode failure detection section consisting of emergency cutoff switches 11 for each of W and -W operated by the switch is attached.

When the diode 8 is operating normally, the detection coil 9 is set to a high voltage cord so as to induce a positive voltage in the control circuit 10.

Therefore, under normal conditions, a positive signal enters the control circuit 10,
It can be determined that the diode 8 is normal.

That is, the control circuit 10 is mainly composed of, for example, a transistor, and the output of the detection coil 9 is applied to its pace. The collector current or emitter current of the transistor is used as a driving power source for the emergency disconnect switch 11. For example, when current is normally flowing through the diode 8, the base of the transistor is reverse biased and the transistor is in a non-conducting state. It is designed to be kept.

Incidentally, the detection coil 9 and the emergency cutoff switch 11 may be provided anywhere on the line connecting each diode 8 and the spark plug 3.

Now, if diode D2 has failed and its reverse breakdown voltage has deteriorated, resulting in a short circuit, the spark plug PI.

When P4 and diode D+ -D4 are in operation, a current flows in the circuit of diode D2 and spark plug P2 in the opposite direction to that in the normal state. This current is connected to the detection coil S,
A negative voltage is induced in the diode D2, and the control circuit 10 can detect that a failure has occurred in the diode D2.

As a result, when the control circuit 10 is operated and the emergency cutoff switch W is opened, the ignition of the spark plug P2 is prevented, and the dangerous situation described in the section of the prior art does not occur.

Similarly, when the emergency disconnect switch W2 opens, the diodes D, D
8, and spark plug P! The circuit consisting of -Ps stops operating, and the engine operates only in the cylinders of spark plugs P, , P, and the output naturally decreases.

However, the engine does not stop functioning at all, so even if a failure occurs while driving, the car will not come to a sudden stop, but will be able to come to a gentle stop, making it completely safe.

As explained above, according to the present invention, in a vehicle ignition system that uses a diode and does not have a distributor, it is possible to prevent accidents caused by a diode failure and to stop the vehicle safely. .

Note that the present invention is not limited to the above-mentioned embodiments, but can be applied to internal combustion engines with various ignition systems.

[Brief explanation of drawings]

Figure 1 is a circuit diagram of an ignition system for an internal combustion engine using a conventional distributor, Figure 2 is a circuit diagram of an ignition system for an internal combustion engine that uses a semiconductor rectifier without a distributor, and Figure 3 is a circuit diagram of an ignition system for an internal combustion engine that uses a semiconductor rectifier without a distributor. A partial circuit diagram of a conventional ignition system for an internal combustion engine in which two rectifiers are connected in series. FIG. 4 is a partial circuit diagram of an ignition system for an internal combustion engine using a semiconductor rectifier according to an embodiment of the present invention. It is. 2...Ignition coil, 3...Spark plug,
4... Igniter amplifier, 5... Ignition signal generator, 6... Battery, 7... Switch, 8... Diode, 9... Detection coil, 10... Control circuit, 11 ...Extremely poor grade 1

Claims (1)

[Claims] 1. In an ignition device for an internal combustion engine in which the output of an ignition coil is applied to a spark plug via a semiconductor rectifier in a predetermined rectification direction, means for detecting the direction of the current flowing through the semiconductor rectifier is provided in the semiconductor current device. An emergency cut-off switch provided on the line is opened in the event of an abnormality by a control circuit installed on the line connecting the ignition plug and the spark plug, and receiving the output of the detection means to determine whether the direction of the current is normal or not. An ignition device for an internal combustion engine characterized by: