JPS5928134Y2 - engine ignition system - Google Patents

Description

[Detailed description of the invention] This invention is an engine ignition system that generates ignition voltages by controlling the energizing currents of the ignition coils to different ignition timings, and supplies each ignition voltage to at least two spark plugs. It is related to.

Conventional ignition devices of this kind control the current flowing through the ignition coil, for example, they are equipped with a semiconductor switching element that switches on and off, and two ignition signal generators that generate ignition signals at different times. The switching element is operated, and the ignition voltage generated in the ignition coil at different times is supplied to each of the two ignition plugs through the power distribution device.

However, since the above-mentioned method requires two ignition signal generators, the device becomes expensive and requires a large installation space.

On the other hand, it has also been proposed to use one ignition signal generator and control the ignition signal with a complex electronic circuit, resulting in two ignition signals being generated at different times. The disadvantage is that the circuit is very complex and expensive.

This invention was developed in view of the above-mentioned drawbacks, and the purpose is to provide an engine ignition system that uses only a single ignition signal generator and is designed to be compact, simple, and inexpensive.

Hereinafter, as shown in Figure 1, spark plugs are installed in the rich mixture cylinder and the lean mixture cylinder, and when these spark plugs are suitably ignited, toxic exhaust gas is discharged from the rich mixture cylinder. An embodiment in which the present invention is applied to an ignition device that purifies toxic exhaust gas by causing an oxidation reaction with excess oxygen discharged from a lean mixture will be described.

In Fig. 1, 1 indicates the first cylinder 1a, the second cylinder 1b, and the third cylinder.
It is a 4-cylinder engine with cylinder 1 c b and 4th cylinder 1d, and the firing order is 1st cylinder 1a → 3rd cylinder 1c → 4th cylinder 1
d→second cylinder 1b.

2 is a carburetor that supplies a lean mixture to the first cylinder 1a and the fourth cylinder 1d; 3 is a carburetor that supplies a rich mixture to the second cylinder 1b and the third cylinder 1c; and 4a.

4b, 4c, and 4d are the respective cylinders 1a, 1b, and lc.

A plurality of spark plugs 1d are respectively attached, 5 is a DC power source, and 6 is an ignition coil supplied with power by the DC power source 5, which is composed of a primary coil 6a and a secondary coil 6b.

γ is a signal coil that is an ignition signal generating coil that generates an ignition signal voltage in synchronization with the 10 revolutions of the four-cylinder engine, and has an intermediate tap 1a.

Although this signal coil T is not shown, it is built into a signal generator installed in the power distribution device.

8 is an ignition timing determining device which receives the ignition signal voltage of the signal coil 7 and determines the ignition timing when the ignition signal voltage reaches a predetermined level (corresponding to a trigger level to be described later);
It is composed of a Schmitt circuit and a switching circuit, and the trigger level of this Schmitt circuit is △e (V)
The ignition timing is set to be reversed (ignition timing).

Reference numeral 9 indicates a high-voltage generator that controls the energizing current of the primary coil 6a of the ignition coil 6 based on the ignition timing of the ignition timing determining device 8, and generates an ignition voltage in the secondary coil 6b; The ignition voltage of the next coil 6b is set to each spark plug 4a.
This is a power distribution device that sequentially distributes power to 4d and 4d, and constitutes two parts of the main body of the power distributor, and is composed of the following parts.

Reference numeral 11 denotes a center electrode, 12a, 12b, 12c, 12, which is attached to a power distributor cap (not shown) and to which an ignition voltage is applied.
13 is a peripheral electrode attached to the cap and connected to each of the spark plugs 4a to 4d; 13 is a peripheral electrode that rotates in synchronization with the 10 rotations of the engine, and connects the ignition electric motor to the center electrode 11 with each of the peripheral electrodes 12a to 1;
This is a power distribution rotor that sequentially distributes power to 2d.

14 controls (increases or decreases) the inductance of the signal coil 7, decreases or increases the ignition signal voltage given to the ignition timing determining device 8, varying the timing at which it reaches the trigger level De, and controlling the ignition timing by the ignition timing determining device 80. This embodiment shows a switch, and this switch 1
4 is connected to one output end of the signal coil T and the intermediate tap 7a, and is opened and closed in accordance with the ignition timing of each cylinder 1a to 1d of the engine to increase or decrease the inductance of the signal coil 7.

That is, this switch 14 opens and closes in synchronization with the rotation of the power distribution rotor 13, that is, with the 10 rotations of the engine.

Next, the operation of the embodiment will be explained using the operation diagrams shown in FIGS. 2 and 3.

FIG. 2A shows the ignition signal voltage waveform generated in the signal coil 7, where a is generated when the detection switch 14 is open, and a is generated when the detection switch 14 is closed.

These signal voltages are constant values from low speed to high speed rotation of the engine 1, and generate values based on the rotation speed and the number of turns of the coil.

Δe is the trigger level of the Schmitt circuit 8.

The opening indicates the ignition timing of each cylinder 1a to 1d of the engine 1.

FIG. 3 is a graph showing the advance angle characteristic of the ignition timing θ with respect to the rotational speed N of the engine 1, where C is a characteristic obtained based on the ignition signal voltage a, and d is a characteristic obtained based on the ignition signal voltage S.

First, when the engine 1 is started, alternating current signal voltages of positive E and negative F are generated in the signal coil 7 in synchronization with the ten revolutions of the engine, as shown in FIG. 2A.

On the other hand, the switch 14 opens and closes corresponding to each cylinder 1a to 1d of the engine 1.

That is, the switch 14 is opened at the ignition timing of the first and fourth cylinders 1a and 1d, and is closed at the ignition timing of the second and third cylinders lb and Ic.

Therefore, when igniting the first cylinder 1a into which a lean air-fuel mixture is taken in, the switch 14 is in the open period, so the signal coil 7 is turned off.
A signal voltage a is generated.

This signal voltage a is applied to a Schmitt circuit 8, and this Schmitt circuit 4 is triggered at position A in FIG.

This trigger position A linearly advances as the rotational speed N of the engine 1 increases, and is based on the ignition advance characteristic shown in FIG. 3C.

Based on this trigger position A, the high voltage generator 9 operates to generate an ignition voltage in the ignition coil 60 and the secondary coil 6b.

This ignition voltage is distributed to the spark plug 4a of the first cylinder 1a via the center electrode 11 of the power distribution device 10 → the power distribution rotor 13 → the peripheral electrode 12a, so the spark plug 4a discharges sparks and the first
To suitably burn a lean air-fuel mixture in a cylinder 1a.

Next, when the switch 14 is closed when igniting the third cylinder 1c into which the rich air-fuel mixture is sucked, the intermediate tap 7a of the signal coil γ and one output end are short-circuited. A signal voltage S having a value smaller than the signal voltage a is generated.

When this signal voltage is applied to the Schmitt circuit 8, the Schmitt circuit 8 moves to the B position which is delayed by θ from the trigger position A at the engine speed N of 10 revolutions when the first cylinder 1a is ignited. is triggered.

As before, this trigger position B linearly advances parallel to the characteristic C as the rotational speed N of the engine 1 increases, and is based on the ignition advance characteristic shown in FIG. 3d.

Based on this trigger position B, an ignition voltage is generated in the ignition coil 60 and the secondary coil 6b, and the power is distributed to the ignition plug 4c via the power distribution device 10, and the ignition plug 4c discharges sparks to cause the rich mixture in the third cylinder 1a. Burn the qi properly.

Thereafter, the lean mixture in the fourth cylinder 1d and then the rich mixture in the second cylinder 1b are suitably combusted in the same manner.

In this way, by changing the ignition timing of the first and fourth cylinders 1a+1d and the second and third cylinders 1bt1c, the toxic exhaust gases CO, HC, and NOX emitted from the second and third cylinders 1bt1c can be reduced. Excess oxygen discharged from the first and fourth cylinders 1a and 1d causes an oxidation reaction and purifies the exhaust gas into harmless exhaust gas, thereby purifying the exhaust gas.

In the above embodiments, the control means is not limited to the mechanical switch 14, but may be an electrical switch constructed from an electronic circuit such as a semiconductor. It can be integrated as a whole.

Furthermore, although the signal coil 7 has an intermediate tap 7a, two other signal coils may be provided and connected in series or parallel to each other for switching.

Furthermore, there is a method in which the ignition timing is varied for the purpose of exhaust gas purification (as explained above, a method in which at least two ignition plugs are installed in the same cylinder and the spark generation timings of these ignition plugs are made to differ). It may also be applied to, and by doing so, it is possible to improve the engine output.

As described above, this invention controls the inductance of a single ignition signal generating coil by means of a control means in accordance with the timing of supplying ignition voltage to one of at least two ignition plugs, and generates an ignition signal. Decreasing or increasing the ignition signal voltage generated in the generating coil to make the timing at which the ignition signal voltage reaches a predetermined level (i.e., the ignition timing determined by the ignition timing determining device) different from the timing of the other ignition plug. As a result, at least two spark plugs are supplied with ignition voltages that occur at different ignition timings. Not only is the device smaller and simpler than the previous device, but the trigger positions corresponding to each of the two spark plugs advance linearly as the engine speed increases. , one ignition plug and the other ignition plug have the effect of independently obtaining different ignition advance characteristics as shown in C and d in FIG.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of this invention, FIG. 2 is an operation diagram showing the signal voltage waveform generated in the signal coil 7 and the ignition timing of each cylinder 1a to 1d in FIG. 1, and FIG. Figure 3 is an engine ignition advance angle characteristic diagram. In the figure, 1 is a multi-cylinder engine, 1a to 1d are first to fourth cylinders, 4a to 4d are spark plugs, 5 is a DC power source, 6 is an ignition coil, 7 is a signal coil, 7a is an intermediate tap, 8 is an ignition timing determining device, 9 is a high voltage generator, 10 is a power distribution device, 1
4 is a switch.

Claims (1)

[Scope of utility model registration request] In a device that generates ignition voltage by controlling the current of the ignition coil at different times, and feeds the ignition voltage generated at different times to at least two spark plugs, it is synchronized with the rotation of the engine. A single ignition signal generating coil that generates an ignition signal voltage, an ignition timing determining device that receives the ignition signal voltage and sets the ignition timing at the time when the ignition signal voltage reaches a predetermined level, and an ignition timing determination device of this ignition timing determining device. an energizing current control device that controls the energizing current of the ignition coil to generate the ignition voltage according to the timing of supplying the ignition voltage to one of the at least two ignition plugs; to control the inductance of the ignition signal generating coil to reduce or increase the ignition signal voltage applied to the ignition timing determining device from the ignition signal voltage applied to the other ignition plug to reach the predetermined level. An engine ignition system comprising control means for controlling the ignition timing of the ignition timing determining device.