JPS61241466A - Ignitor for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve combustion efficiency by using a dc voltage power source having the energy sufficient for the continuation of electric discharge and markedly controlling the ignition energy for the engine operation state. CONSTITUTION:In an electric-discharge continuation time control circuit 23, the signals for detecting the engine operation state which is obtained according to an acceleration speed sensor 25, load detecting sensor 26, idling detecting sensor 27, and a starting-time detecting sensor 28 are input into an OR circuit 29. The signals for controlling the dc high voltage power sources 15-18 connected to the spark plugs 6-9 through the second switching circuits 19-22 are generated. A pulse generating circuit 24 connected to the circuit 23 generates the pulses in a certain frequency per revolution of a crankshaft in synchronization with the engine revolution. Therefore, the crank angle for the cycle of pulses is always set constant and the trouble of too long or too short electric discharge time is avoided. Therefore, the combustion efficiency can be improved, and the waste use of energy can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention relates to an ignition device for an internal combustion engine, and in particular to an ignition device for an internal combustion engine suitable for changing spark energy according to the operating state of the engine to improve combustion efficiency. Regarding the ignition device.

[Background of the invention]

Conventionally, as shown in Japanese Unexamined Patent Publication No. 59-103968, an ignition coil with independent primary and secondary windings was connected, one of which was connected to the ignition plug via a power distributor, and the other to a DC high-voltage power source. An ignition device has been proposed in which the ignition energy is controlled by increasing the ignition energy by increasing the ignition energy, and further by cutting off the DC high-voltage power supply. However, since such ignition devices use a power distributor, the maximum discharge duration is determined by the fixed electrode and rotating electrode within the power distributor, making it difficult to significantly control the ignition energy.

For example, if we take a 6-cylinder 4-stroke engine as an example and assume that the angle at which the fixed electrode and rotating electrode in the power distributor face each other is 36°, and the angle at which power is actually distributed is 18°, then the engine speed is 600. At °rpm, the maximum discharge duration is only 1 m880 sh, therefore,
Even if the discharge duration is extended using the DC voltage power source, the time during which the spark plug actually produces a spark does not extend, which has the disadvantage that energy is wasted.

[Object of the Invention] The object of the present invention is to improve combustion efficiency by controlling ignition energy (discharge duration) according to engine operating conditions;
Moreover, it is an object of the present invention to provide an ignition device for an internal combustion engine that can prevent energy wastage.

[Summary of the invention]

The present invention improves combustion efficiency and reduces energy waste by using a DC voltage power source with sufficient energy to sustain discharge and greatly controlling ignition energy for each engine operating condition. It is intended to prevent this.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

FIG. 1 shows an embodiment of the invention.

In the figure, the number of ignition coils 2, 13, 4, and 5 is the same as the number of cylinders in one engine (four cylinders in this example);
3, 4.5, respectively, the first switching circuit 11, 12, 13° 14 and the spark plug 6, 7, 8.9
and a primary winding 2a of the ignition coil 2, 3, 4.5.
, 3a.

A power supply battery 1 is connected to one of 4a and 5a, and a corresponding first switching circuit 11 and 12 is connected to the other side, respectively.
are connected to form a current cutoff circuit. Further, corresponding spark plugs 6, 7°8.9 are connected to one of the secondary windings 2b to 5b of the ignition coils 2, 3, 4.5, respectively, and the secondary winding 2a.

A first switching circuit 1 is connected to the other of 3a, 4a, and 5a.
Ignition coils 2, 3 when 1, 12, 13, 14 are turned off
, 4, 5 secondary windings 2b, 3b.

DC high-voltage power supplies 15, 16, 17, and 18 are connected to each other so as to have the same polarity as the high voltage generated at terminals 4b and 5b. The voltage value of this DC high voltage power supply 15, 16° 17.18 is lower than the discharge starting voltage of the spark plugs 6, 7, 8.9, and the spark plugs 6, 7° 8.9 are discharged due to other factors. The first switching circuit 11 has a voltage value such that no current flows unless the voltage occurs (IKV to -4KV).
Ignition signal control circuit 10 connected to ゜12.13.14
The spark plugs 6 and 7 connected to each cylinder of the engine are activated based on the ignition signal obtained in synchronization with the engine rotation and ignition timing.
, 8.9, the ignition signal is passed through the first switching circuits 11, 12, . 13. ．． This is for distribution to 14 people.

The discharge duration control circuit 23 inputs signals for detecting the operating state of the engine obtained from the acceleration detection sensor 25, the load detection sensor 26, the idling detection sensor 27, and the starting detection sensor 28 to the OR circuit 29. Each spark plug 6, 7 via a switching circuit 19, 20, 21° 22
, 8.9 are connected to the DC high voltage power supplies 15, 16, 17.
This is a circuit that generates a signal to control 18. A pulse generator 24 connected to the discharge duration control circuit 23 generates a fixed number of pulses per revolution of the crankshaft in synchronization with the rotation of the engine. Assuming that the discharge time is always constant, the angle through which the crankshaft rotates while the discharge continues is small at low speeds and large at high speeds. Therefore, if the discharge time is adjusted to a low speed, the discharge time is too long at a low speed, and conversely, if the discharge time is adjusted to a high speed, the discharge time is too short at a low speed, resulting in poor ignitability. By the way, when the pulses are synchronized with the rotation of the engine, the crank angle with respect to the period of the pulses is always constant. Therefore, when the discharge time is controlled by this pulse, the problem of the discharge time being too long or too short does not occur.

FIG. 2 shows the second switching circuit 19 shown in FIG. 1, the DC high voltage power supply 15. A detailed circuit of the discharge duration control circuit 23 is shown. Further, FIG. 3 shows the operation of FIG. 2. In FIG. 2, circuits and elements corresponding to the circuit shown in FIG. 1 are given the same reference numerals. In FIG. 2, the second switching circuit 19 is composed of a transistor 3o that continues the DC high voltage power supply 15, and a transistor 81 that controls this transistor 30. Also.

The DC high voltage power supply 15 is a general C-DC converter composed of two transistors 37 and 38, a transistor 39, a rectifier circuit 40, and a capacitor 41.

The discharge duration control circuit 23 includes two counters 32 which are time setting circuits that set a time width corresponding to the discharge duration.
．． 33 counts the pulses generated by the pulse generator 34, and the outputs of the counters 32 and 33 are transmitted to the transistors 36 and 33.
The inverter element 35 and OR element 34 are used to select according to the operating state of the engine.

The waveform A-H in FIG. 3 is the waveform A-H shown in FIG.
3(A) is the signal waveform of the stitching circuit 11 in FIG. 1, and FIG. 3(B) is the time taken for the signal in FIG. 3(A) to become "Low". This is a waveform obtained by integrating the signal in FIG. 3(A) in order to delay the signal. Also, Figure 3 (
C) is the output waveform of the pulse generator 24, FIG. 3(D) is the output waveform of the counter 32, FIG. 3(E) is the output waveform of the counter 33, and FIG. 3(F) is when the engine is in an acceleration state/high This is an energy request signal outputted via the OR element 34 when more ignition energy is required than during normal driving, such as in a loaded state, idling state, or starting state. Also, Figure 3 (
G) is the signal waveform that connects and disconnects the DC voltage power supply 15, and FIG.
H) is the secondary voltage waveform of the ignition coil 2, and FIG.
) to (H), the logical values corresponding to each signal are a to h, respectively.
The operation of the embodiment shown in the first figure in zero order will be explained using second order and third order. Note that the ignition signal control circuit 1
0 outputs independent signals to the ignition coils 2, 3, 4, and 5.

Here, one representative example will be explained.

First, when the first switching circuit 11 is turned off as shown in FIG. 3(A), at the instant of this turning off, current flows through the ignition plug 6 and ignites the air-fuel mixture. If current does not flow through the ignition plug 6 once, dielectric breakdown will occur in the ignition plug 6, and after that, current will flow from the DC high voltage power supply 15 to the ignition plug 6, as shown in Fig. 3 (H
), the discharge continues. Since this discharge continues until the DC high voltage power supply 15 is turned off, this DC high voltage power supply 1
The discharge time is controlled by controlling the time until 5 is turned off. Here, the two counters 32 and 33 in the discharge duration control circuit 23 are input to the clock terminal C after the reset signal input to the reset terminal R changes from "High" to "Low" as shown in FIG. ), the number of pulses as shown in FIG.
h”, which is obtained from the first switching circuit 11 as a reset signal for the counters 32 and 33.
When a signal A as shown in FIG.
The output signals R and E as shown in (E) are set respectively after ignition and become "High" for a period of time.
The output signal as shown in Fig. 3 (D) is “H”.
The number of pulses of the clock signal C shown in FIG. 3(C) while the counter 33 is "High" is nl, and while the output signal E shown in FIG. 3(E) output from the counter 33 is High. The number of pulses of the clock signal C shown in 31st!!I (C) is n8, and the number of pulses shown in FIG. 3 (C) output from the pulse generator 24 during one rotation of the crankshaft is n. , binding, 0≦n1≦ns <<n.

Then, the output signal E as shown in FIG. 3(E) outputted from the counter 33 becomes "High" from the time when FIG. 3(D) outputted from the counter 32 is "High".
The logical value g of the output signal G outputted from the discharge duration control circuit 23 as shown in FIG.
When the energy request signal F as shown in FIG. 3(F) is High, g = b + d + e = b + e, and when the energy request signal F as shown in FIG.
When Q w u, the input terminal of the OR element 34 connected to the collector of the transistor 36 to turn on the transistor 36 becomes "Low". Therefore, the discharge duration control circuit 23 outputs the signal shown in FIG. 3 (G). The logical value g of the output signal G as shown in FIG.
Since the discharge of the ignition plug 6 continues until it becomes ``OW'', the discharge time becomes longer when a large amount of ignition energy is required, such as during acceleration, high load, idling, and starting. The same applies to the output of .

In this embodiment, the discharge duration is controlled using two counters and a pulse generator synchronized with the rotation of the engine as a time setting circuit for setting the discharge time.

Transistors and inverter elements as selection circuits.

Although an OR element was used, instead of the above-mentioned counter, a plurality of time setting circuits using signals from a crank angle sensor, etc., and one time setting circuit from the plurality of time setting circuits depending on the operating state of the engine were used.
It is clear that this can also be realized using a selection circuit that selects one.

In addition, since this embodiment does not use a power distribution device, the discharge time is not controlled by the time that the fixed electrode and rotating electrode face each other in the power distribution device, so the 1 ignition energy (discharge time) can be controlled over a wide range. .

Therefore, according to this embodiment, the discharge time can be lengthened only when a large amount of ignition energy is required, such as during acceleration, high load, idling, and starting, and the ignition energy can be reduced at other times.

Moreover, since the discharge time is automatically corrected according to the engine speed, it is possible to provide an ideal ignition system that provides ignition energy that meets the requirements of the engine.

Further, according to this embodiment, since there is no power distributor, it is possible to eliminate the problem of energy loss and noise generation due to the gap between the fixed electrode and the rotating electrode in the power distributor.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to optimally control the ignition energy according to the operating state of the engine, improve combustion efficiency, and prevent wastage of energy.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
A detailed circuit diagram of the switching circuit, DC voltage power supply, and discharge duration control circuit, and FIG. 3 is an operating waveform diagram of the circuit of FIG. 2. 2.3, 4.5... Ignition coil, 10... Ignition timing control circuit, 11, 12, 13.14... First switching circuit, 15, 16, 17.18... DC high voltage Power supply, 19, 20, 21, 22... Second switching circuit, 23... Discharge duration control circuit, 24... Pulse generator, 25... Acceleration detection sensor, 26...
Load detection sensor, 27... Idling detection sensor,
28...Start 1 o'clock detection sensor, 32, 33...Counter. 39...Transformer, 40...Rectifying element.

Claims (1)

[Claims] 1. A plurality of spark plugs corresponding to the number of cylinders of the engine, a plurality of ignition coils corresponding to the spark plugs, and a plurality of spark plugs connected to the primary windings of each of the ignition coils. 1 switching circuit, an ignition timing control circuit that controls the switching circuit, a plurality of DC high voltage power supplies connected to each secondary winding of the ignition coil, and a plurality of second DC high voltage power supplies that control the DC high voltage power supplies. An ignition device for an internal combustion engine, comprising: a switching circuit; and a discharge duration control circuit that controls the second switching circuit according to the operating state of the engine. 2. In the invention as set forth in claim 1, the discharge duration control circuit includes a time setting circuit that sets a time width corresponding to a plurality of predetermined discharge durations according to the rotation speed; An ignition device for an internal combustion engine, comprising a selection circuit that selects the plurality of time setting circuits based on a detection signal that detects an operating state of the engine.