JPS6141990Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing signal generation circuit for an engine, and particularly to an ignition timing signal generation circuit for a two-plug ignition engine.

In automobile maintenance, it is important to check the ignition timing of the engine. Generally, in order to measure the ignition timing of a two-plug ignition engine that has two spark plugs in one cylinder, two
It was necessary to measure each spark plug individually using a sensor, or to measure each spark plug separately using a single sensor. Therefore, in the former case, two sensors and their respective detection circuits are required, which has the drawback of increasing cost and size. Furthermore, the latter method has disadvantages in that it is time-consuming in operation (measurement) and takes a long time to measure. The present invention was made to eliminate these drawbacks, and is a circuit that generates an ignition timing signal for the other spark plug using a sensor set on one spark plug and a signal on the negative side of the ignition coil. The purpose is to provide

The ignition timing signal generation circuit according to this invention will be explained below with reference to the drawings of FIGS. 1 to 4.

FIG. 1 is a block diagram showing one embodiment of the present invention. In FIG. 1, 11a and 11b are two ignition circuits of a 4-cylinder, 2-plug ignition type engine. To explain this simply, 5a and 5b are ignition coils 6a and 6b are distributors, and 7a to 7d and 8a to 8d are spark plugs for the first to fourth cylinders. In the case of a two-plug ignition system, two spark plugs are installed in one cylinder, and in the case of Fig. 1, each spark plug 7 is installed.
a and 8a, 7b and 8b, 7c and 8c, 7d and 8d
are paired and installed in the first to fourth cylinders.
The sensor 1 is attached to a plug cord 1a connecting the distributor 6a and the first cylinder spark plug 7a.

A sensor 1 detects ignition of the first cylinder, and a sensor detection circuit 2 processes the detection signal. Then, the waveform shaping circuit 3 captures the rising edge of the output A of the sensor detection circuit 2, shapes the waveform, and sends it to the ignition timing measurement circuit 10 as the reference timing for ignition in the first cylinder spark plug 7a. 3 and 4 are time charts for explaining the operations of FIGS. 1 and 2. In FIG. 3, the timing of a specific peak C ₁ of the signal C is the timing of a specific peak D ₁ of the signal D.
Figure 4 shows the timing chart when the timing of peak C ₁ is ahead of the timing of peak D ₁ .
This is a time chart when the timing is behind. Signals A and B are input/output pulse waveforms of the waveform shaping circuit 3, and the ignition timing of the spark plug 7a substantially coincides with the rise of the signal B.

The waveform shaping circuit 9 shapes the waveform of the ignition coil primary side signal D obtained from the negative terminal 9b of the ignition coil 5b of the ignition circuit 11b, and also changes the ignition coil primary side signal D to its rising edge. Synchronize and format. The waveforms of the input/output signals D, E, and F are as shown at D, E, and F in FIGS. 3 and 4. Further, the signal waveform of the negative terminal 9a of the ignition coil 5a of the ignition circuit 11a is as shown in FIG. 3 and FIG. 4C.

The signal E is a pulse obtained by shaping the waveform of the signal D, and has a delay of about 2 ms compared to the rise of the signal D. Further, the signal F is synchronized with the rise of the signal D, and its pulse width is determined by the time constant of the waveform shaping circuit 9. Note that the signals C and D are the contacts 12a and 12b.
The ignition of each spark plug 7a to 7d and 8a to 8d is caused by the opening and closing of the contact point 12.
When the ignition coils 5a and 12b are opened and closed, the electromotive force generated on the secondary side of the ignition coils 5a and 5b is transmitted to each spark plug 7a to 7d by the deflector 6a and 6b.
and 8a to 8d. Therefore, the specific peak C ₁ of signal C
(i.e. _, the ignition timing of the spark plug 7a) and the rise of the signal A almost coincide with each _other , and in the case of the state shown in FIG.
ignition timing, and in the case of the state shown in Figure 4, the peak of signal D immediately before pic _C1 .
The timing of _D1 matches the ignition timing of the spark plug 8a. Therefore, the ignition timing of the spark plug 8a is at its peak in the state shown in FIG.
It is obtained by detecting the peak D ₁ of the signal D immediately after C ₁ , or in the case of the situation shown in FIG. 4, by detecting the peak D ₁ of the signal D immediately before the peak C ₁ . Note that the difference in timing between peak C ₁ and peak D ₁ is based on peak C ₁ and signal D 1.
within the period of time (peak C ₁ as shown in Figure 4)
(within T/2 hours before and after).

This operation will be explained in detail below using FIG. 2.

Figure 2 shows the waveform shaping circuit 3 and the reference signal generation circuit 4.
4a is a direct clear synchronous binary counter,
The operation is performed at the falling edge of the clock CK, and if the clear CLR input is at the "L" level, all outputs of the counter 4a become "L". The signal G that becomes the clear CLR input of the counter 4a is AND
The output of the gate 3b is inverted by the inverter 3C, and is synchronized with the rise of the output B of the waveform shaping circuit 3. First, the counter 4a is cleared by the signal G at the ignition timing of the spark plug 7a,
Start counting the pulse signal E. As described above, the difference between the ignition timing of the first cylinder of the ignition circuit 11a and the ignition timing of the first cylinder of the ignition circuit 11b is the peak C ₁
is within the time of one cycle of signal D,
Here, since there are four cylinders, the ignition timing of the spark plug 8a coincides with the timing of the rise of the pulse signal F, which comes immediately after the fourth fall of the pulse signal E after the counter 4a is cleared by the signal G. Therefore, the output Qc of the counter 4a when the fourth pulse signal E falls is latched 4b.
As input. The output of this latch 4b goes to the "H" level at the rising edge of the clock, and if the clear input is at the "L" level, the output of the latch 4b goes to the "H" level.
becomes “L”. In other words, in synchronization with the fourth fall of pulse signal E, signals 1 and L go to "H" level, and after output L of latch 4b goes to "H" level, AND gate 4c receives pulse signal F, In synchronization with the rise of pulse signal F,
The output J of the AND gate 4c is output.

This rising edge is captured by the one shot 4d and becomes the output signal H, and at the same time, the output signal K of the gate 4e
As a result, latch 4b is cleared.

Note that signals from automobile engines are extremely noisy, and the noise may cause malfunctions in electrical circuits. Therefore, in the present invention, as described above, the counter 4a is cleared every cycle of the signal A with the signal G synchronized with the ignition timing signal A of the first cylinder of the ignition circuit 11a, and the counter 4a is cleared in the ignition circuit 11b.
By clearing the latch circuit 4b every cycle of the signal H using the signal H synchronized with the ignition timing of the first cylinder, the influence of the above-mentioned noise is prevented as much as possible, and the circuit operation is made more reliable.

Thereafter, the same operation as above is repeated. The rising timing of the signal H obtained in this way is
At the same time as the pulse signal F rises, the ignition circuit 11b
This corresponds to the ignition timing of the first cylinder. This signal is sent to the ignition timing measuring circuit 10 of FIG. 1 and used as the ignition timing of the ignition circuit 11b.

As described above, according to the present invention, the ignition coil signal of the second ignition circuit of an engine having at least two spark plugs in one cylinder and two ignition circuits for each is counted. , a counter that is cleared by the ignition timing signal of the plug of the first ignition circuit, a latch circuit that holds the value when the output of the counter reaches a predetermined value, and an output of the latch circuit and a second ignition circuit. The present invention includes a pulse generating circuit that generates an ignition timing pulse for the plug of the second ignition circuit from the ignition coil signal of the ignition coil, and a means for clearing the latch circuit with the pulse generated from the pulse generating circuit.
A low-cost and small-sized timing signal generating device using only one sensor can be obtained, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a circuit diagram of the main part related to FIG. 1, and FIGS. 3 and 4 illustrate the operation of FIGS. 1 and 2. This is a time chart for explanation. 1...Sensor, 2...Sensor detection circuit, 3...
Waveform shaping circuit, 4...Reference signal generation circuit, 5a,
5b...Ignition coil, 6a, 6b...
Distributor, 7a, 7b, 7c, 7d,
8a, 8b, 8c, 8d...Spark plug, 9...
Waveform shaping circuit, 10...Ignition timing measurement circuit, 11a, 11b...Ignition circuit, 12a, 12
b...Point contact, 4a...Counter, 3b,
4c, 4e...AND gate, 4b...Latch,
3a, 4d...One shot.

Claims (1)

[Scope of utility model registration request] Count the ignition coil signal of the second ignition circuit of an engine with at least two spark plugs in one cylinder, each with two ignition circuits for the plugs, and count the ignition coil signal of the plug of the first ignition circuit. A counter that is cleared by the ignition timing signal, a latch circuit that maintains the state when the output of the counter reaches a predetermined value, and a second ignition coil signal from the output of the latch circuit and the ignition coil signal of the second ignition circuit. An ignition timing signal generation circuit for an engine, comprising: a pulse generation circuit for generating an ignition timing pulse for a plug in an ignition circuit; and means for clearing the latch circuit with a pulse generated from the pulse generation circuit.