JPS6027929B2 - timing measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the relative timing of two impulse trains.

Conventionally, when measuring the timing of engine ignition or fuel injection, for example, an angle encoder is attached to the crankshaft, and the pulse signals obtained from this encoder are counted to determine the delay or advance of the top dead center signal and the ignition signal. Although it is possible to install an encoder on the crankshaft for measurements in a laboratory, etc., it is not possible to implement this on all products on the production line. is extremely difficult. In addition, as a simple measurement method, a rectangular wave signal train that rises in response to the top dead center signal and falls in response to the ignition signal is generated, and the average value obtained by passing this through a low-pass filter is indicated in an analog manner. However, when the engine is rotating at low speed, the period of the original square wave signal becomes long, causing the instruction to pulsate, making it difficult to discuss.

SUMMARY OF THE INVENTION An object of the present invention is to realize a timing measuring device that has high measurement accuracy, digitally displays data in arbitrary units, is easy to take, and has a simple configuration.

FIG. 1 is a block diagram showing one embodiment of the present invention.
I is a generator of a top dead center signal of a piston in an arbitrary cylinder of the engine to be measured, and is composed of, for example, a protrusion made of a magnetic material attached to the crankshaft and a fixed electromagnetic pickup provided opposite to the protrusion.

G2 is the generator of the ignition signal in the cylinder, for example consisting of a coil coupled to the ignition circuit of the cylinder. When generating a fuel injection signal, for example, a protrusion made of a magnetic material attached to a cam of a fuel injection pump and an electromagnetic pickup opposed to the protrusion are used. Note that generators GI and G2 may be provided with front-layer amplifiers as necessary. CNTI to CNT5 are counters, DEC is a decoder, CPI to CP3 are clock pulse oscillators, ANDI to AND3 are AND gate circuits, and RM is a ratio calculator, which is, for example, a so-called thinning circuit. COMP is a digital comparator,
GC is gate opening/closing control circuit, DEL is delay circuit, LAT
I is a latch circuit, and DIS is a display device. Generator GI
The top dead center signal (Fig. 2 g1) obtained from the counter CN
For example, the ignition signal (second illustration) obtained from the generator G2 is input to the count signal input terminal of the TI and is input to the counter CN.
When applied to the reset signal input terminal of TI, counter CN
The count value of TI is "0" or "2" as shown in Figure 2 cl.
It changes periodically over a range of .

This counting output is introduced into the decoder DEC, and as shown in FIG.
As shown in the figure, the signal a is sent from the output terminal A during the period when the count value is "0", and the signal a is sent from the output terminal B during the period when the count value is "1".
When the signal b is sent out from the output terminals A and C during the period when the count value is "2", the AND gate circuits ANDI and AND2 become as shown in FIG.
d2, and the counter CNT4 is kept in the harp reset state while the signals a and c from the output terminal A of the decoder DEC are applied to the reset signal input terminal. In response to the conduction of the AND gate circuits ANDI and AND2, the output pulse of the clock pulse oscillator CPI becomes ANDI.
and counters CNT2 and CNT3 via AND2
The respective counts are shown in Figure 2 C2 and C.
It changes like 3.

The count output of the counter CNT2 is introduced as a control signal to the ratio calculator RM, which changes the frequency of the output signal of the clock pulse oscillator CP2, that is, the reference pulse signal, to a frequency proportional to the count value of the counter CNT2. Counter CN
T4 is the signal C and a from the output terminal A of the decoder DEC.
During the extinction period of , the output pulse signals of the ratio calculator RM are counted, and the counted value C4 is compared with the counted value C3 of the counter CNT3 in the comparator COMP. As is clear from FIG. 2, at the same time as the counter CNT4 starts counting, the signal b is sent from the output terminal B of the decoder DEC to the gate opening/closing control circuit GC, and the AND gate circuit AND3 is made conductive (second and3), the output signal of the clock pulse oscillator PP3 is introduced into the counter CNT5 via AND3 and counted.

Counter CN compared in comparator COMP
When the count values of T3 and CNT4 match, a match signal is sent from COMP, and the control signal from the gate opening/closing control circuit GC disappears and the AND gate circuit AND3 is shut off.At the same time, the match signal from COMP causes the counter CNT to
A count value of 5 is loaded into the latch circuit LATI and displayed on the display device DIS.

Incidentally, the match signal from the comparator COMP is sent to the delay circuit D.
The signal is introduced to the reset signal input terminal of the counter CNT5 via the EL, and is reset to zero in preparation for the next measurement. If the period of the top dead center signal g1 is x (sec), the time from the appearance of the top dead center signal until the appearance of the ignition signal g2 is y (sec), and the oscillation frequency of the PI to the clock pulse oscillator is fl, Count value c2'' until counter CNT2 is reset to zero, c2=fl×x Count value c3' until counter CNT3 is reset to zero
becomes c3'=fixy.

In addition, when the ratio calculator RM is formed using an IG Hayabusa ratio calculator, the number of digits is ・n (=1, 2, 3,...)
and the oscillation frequency of clock pulse oscillator CP2 is f2
, the time from when the counter CNT4 starts counting until its count value matches the count value of the counter CNT3 is △t
(sec), and if the count value of CNT4 when both count values match is c4', then c4'=fixx×10-n×ne×
Δt...fixy Therefore, fixy Δt=fixf2xlo-nxx.

If the oscillation frequency of the clock pulse oscillator CP3 is f3, the count value C5 of the counter CNT5 when the count value of the counter CNT4 matches the count value of CNT3 is c5=ne×△t, so C5: curtain×・bi Become X beauty.

As is clear from the above equation, the count value c5 of counter CNT5
From this, it is possible to know the ratio of y to x, that is, the timing of arrival of the ignition signal.

For example, if x=1 hsec, y=ear hsec, then fl
If you choose =10 female HZ, c2=1000, c3=500
For example, if the number of digits n of the ratio calculator RM is 4, then f
2: IMHZ, if you choose f3 = 3 ship day 2, misery 1 = 36
0 C5=36oX magazine.

= 180 (degrees), and the arrival timing of the ignition signal relative to x = 360 degrees can be indicated in degrees.

Also, for example, x=1hSeC, y=9hSeC, n=
In the case of 4, if f2=IMHZ and f3=1 plate day 2 are selected,
Poison x 1 = 100C5 = oo

In the above case, the ignition signal arrives every other cycle of the top dead center signal.4
Although the case of a cycle engine has been explained, when an ignition signal arrives every cycle of the top dead center signal like a two-cycle engine, the clock pulse oscillators CP2 and CP3 are used.
The timing of the ignition signal can be measured by applying each oscillation frequency of the oscillation frequency to the reset signal input terminal of the power button CNTI using a signal as a frequency sensor.

By setting the count value c3' of the counter CNT3 to a fixed constant w, it is possible to indicate the frequency of the top dead center signal, that is, the rotational speed of the engine to be measured.

If the rotational speed of the engine to be measured is Nrpm, the period of the top dead center signal g is equal to (Sec), so the force counter CNT
The count value c5 of 5 is Takumi = Misanii Ashi.

Therefore, if the oscillation frequencies f2 and f of P2 and CP3 and the fixed constant w are selected in the clock pulse oscillator so that the groove W=1, then c
Since 5=N, the rotational speed of the engine to be measured can be determined from the count value of the counter CNT5.

FIG. 3 is a block diagram showing another embodiment of the present invention,
CNT6 is a counter, LAT2 and LAT3 are latch circuits, FF is a flip-flop circuit, and other symbols are the same as in FIG.

In this embodiment, the oscillation output of the clock pulse oscillator PI is introduced into the count signal input terminal of the counter CNT6, the top dead center signal from the generator GI is applied to the reset signal input terminal of the counter CNT6, and the latch circuit LAT2
When this signal is added as a command signal, the count value corresponding to the period of the top dead center signal, that is, c2 in the previous embodiment, is stored in the latch circuit LAT2.

Furthermore, when the ignition signal from the generator G2 is applied as a command signal to the latch circuit LAT3, LAT3 receives a count value corresponding to the time difference between the top dead center signal and the ignition signal that arrives immediately after that, that is, the previous embodiment. c3' is stored. Furthermore, in this embodiment, the flip-flop circuit FF is set by the ignition signal from the generator G2, and the FF is reset by the top dead center signal from the generator GI.
By configuring the counter CNT4 to start counting at the same time as F is reset, and to make the AND gate circuit AND3 conductive, CNT4 and CNT5
The counting start time can be made exactly the same as in the previous embodiment.

Therefore, the oscillation frequency of the clock pulse oscillator CP2 is changed by the ratio calculator RM in proportion to the value stored in the latch circuit LAT2, and the output signal of the RM is changed to the counter CNT.
4 is introduced and counted, and the counted value is sent to the latch circuit L.
Counter CNT takes the time until it matches the stored value of AT3.
5, the arrival timing of the ignition signal can be known as in the previous embodiment.

The above description has been made regarding the case of measuring the relative timing of the engine top dead center signal and the ignition or fuel injection signal, but it is of course possible to measure the relative timing of any impulse train consisting of two other trains. By appropriately selecting the oscillation frequencies f2 and f3 of the clock pulse oscillators CP2 and CP3, it is possible to stably and accurately provide timing instructions in any display unit.

Brief explanation on the south side of the figure. Figs. 1 and 3 are block diagrams showing one embodiment of the present invention, and Fig. 2 is a waveform diagram for explaining its operation. GI and G2: signal generators , CNTI or CNT
6: Counter, DEC: Decoder, CPI or CP3
: clock pulse oscillator, ANDI or AND3: AND gate circuit, RM: ratio amplifier, COMP: comparator, GC: gate opening/closing control circuit, DEL: delay circuit, LATI or LAT3: latch circuit, DIS: display device, FF: flip-flop circuit. be.

Figure l Figure 2 Figure 3

Claims (1)

[Claims] 1 A first counter that measures the period of the first impulse train, and a second counter that measures the time difference between any impulse in the second impulse train and the impulse in the first impulse train that arrived immediately before it. and a circuit for transmitting an impulse train with a frequency proportional to the count value of the first counter, and a circuit for transmitting an impulse train with a frequency proportional to the count value of the first counter, and in response to arrival of an impulse of the first impulse train that arrives first after the arrival of an impulse in the second impulse train. a third counter that starts counting the output signals of the sending circuit; and a fourth counter that measures the time from the start of counting of the third counter until the counted value matches the counted value of the second counter. A timing measurement device characterized by comprising a counter.