JPS61116075A - Ignition timing measuring device for engine - Google Patents

Abstract

PURPOSE:To promptly detect the correct ignition timing by computing the rotational angle of a crank shaft from the top dead center to the ignition timing in accordance with each output signal of an ignition timing detecting means and a reference angle detecting means and by displaying the computed results. CONSTITUTION:Articles to be set according to the type of a distributor 15 of a vehicle and articles to be ammended according to the types of vehicle, etc. are set in a setting device 11. The value of a cycle angle A from the top end center of a first cylinder to that in the vicinity of next top end center, and the value of a deviation angle Z before the top end center are read out from a memory 12 to input them to a computing circuit 10. The distributor 15 is provided with an angle detection means 1 and a reference angle detection means 2, while its output is input to a computing circuit 14 together with the output of an ignition timing detection means 3. Then the rotation angle X of a crank shaft from the top dead center of the cylinder to the ignition timing is computed by the above computing means according to the predetermined operation formula. And consequently the value of the obtained results X is displayed on a display 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to an ignition timing measuring device that can accurately determine the ignition timing of an engine during inspection and maintenance of automobiles and other vehicles, especially vehicles with electronic advance devices. Namu (2) Conventional technology Conventionally, a timing light is generally used to know the ignition timing of an engine.The timing light's bin amplifier is attached to the high pressure cord of the first cylinder of the engine, and the timing light is used to start the crank. The advance angle is observed by comparing the alignment mark on the pulley with the advance angle scale attached to the engine body.

(3) Problems to be Solved by the Invention However, according to the measurement of ignition timing using this timing light, the timing light illuminates the alignment mark and the advance angle scale to observe the advance angle, so the surrounding area is bright. It is difficult to observe the ignition timing in a certain location, making it difficult to know the ignition timing accurately, and there are also problems in that measurement errors occur due to different people measuring the ignition timing.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a measuring device that can accurately determine the ignition timing even in a bright place.

(4) Means for solving the problem In order to achieve this object, the present invention provides a signal from an angle measuring means for measuring the rotation angle of the crankshaft of the engine and a reference value near the top dead center of a predetermined cylinder of the engine. The rotation angle of the crankshaft from the top dead center of the cylinder to the ignition timing is calculated by inputting the signal from the reference angle detection means for detecting the angle and the signal from the ignition timing detection means for detecting the ignition timing of the cylinder. It is characterized by comprising a calculation means for calculating the calculation result, and a display means for displaying the calculation result.

(5) The action calculation means calculates an angle corresponding to the time between the signal from the ignition timing detection means and the reference angle detection means based on the signal from the angle measurement means, and then calculates the angle between the reference angle and top dead center. A correction calculation is performed using a known correction angle, and the angle from the top dead center to the ignition timing, which is the calculation result, is displayed on the display means.

(6) Examples An embodiment of the present invention will be described with reference to the drawings.

(1) shows the angle measuring means already attached to the distributor (15) of the engine, and the angle measuring means (
1) consists of a timing rotor (1a) that is fixed to the shaft of the engine's distributor and rotates at the rotational speed of the engine at l/X, and a pickup coil (1b) that is installed close to the timing rotor (1a). , the timing rotor (la) has N teeth formed at equal intervals on its periphery, so that when the timing rotor (1a) rotates once, N teeth are formed as shown in FIG. 3(a). Generate a signal.

(2) indicates a reference angle detection means which is already attached to the distributor (15) of the engine; and (4) the reference angle detection means (2) is fixed to the shaft of the distributor). A rotating timing rotor (2a) and a rotating timing rotor (1) provided adjacent to the timing rotor (2a).
The timing rotor (2a) has one tooth formed on its periphery, and when these teeth are near the compression dead center of the first cylinder, the timing rotor (2a) is most picked up. Since the pickup coil (2b) is installed in a position close to the pickup coil (2b),
The voltage waveform from (b) becomes as shown in (b) of FIG. 3, and the zero point where this voltage waveform changes from positive to negative is near the top dead center.

(3) indicates an ignition timing detection means, which consists of a conventionally known pickup coil attached to the high voltage cord of the first cylinder of the engine, and the voltage waveform of the big amplifier coil is shown in (C) of FIG. ), and the rise of the waveform becomes the ignition timing of the first cylinder.

(4), (5), and (6) are the pickup coil (tb) of the angle measuring means (1) and the reference angle detecting means (2).
) and the first big amplifier coil (2b) connected to the pickup of the ignition timing detection means (3). The second and third waveform conversion circuits are shown, and the first waveform conversion circuit (
4) is a monostable multivibrator that can emit a pass signal at the same time as the input signal changes from positive to negative. The second waveform conversion circuit (5) is composed of, for example, a monostable multivibrator that generates a pulse at the same time as the input signal changes from positive to negative, and converts the signal waveform of (b) in Figure 3 to (e) of the same figure. It has a function of converting the signal waveform into the signal waveform of
The waveform modification circuit (6) is composed of, for example, a monostable multivibrator that generates a pulse at the same time as the input signal changes from zero to positive, and generates a pulse as shown in FIG. 3(f) every time the signal waveform shown in FIG. 3(C) rises. It has the function of

(7) indicates a counter circuit, and the counter circuit (7)
) connects its input to the first waveform conversion circuit (4) and its control input to the second waveform conversion circuit (5), inputs the pulse from the second waveform conversion circuit (5), and converts the first waveform. The pulses from the conversion circuit (4) are counted and the second waveform conversion circuit (
Counting is stopped by the next pulse from 5), and the count aN is determined.

(8) and (9) indicate first and second time counting circuits, and the first time counting circuit (8) is, for example, a timer, and its input is connected to the first waveform conversion circuit (4). The clock pulses between the pulses from the first waveform conversion circuit (4) are counted to calculate the time y between the pulses, and the second time counting circuit (9) is composed of, for example, a timer and its control input is is connected to the second waveform conversion circuit (5) and the third waveform conversion circuit (6), and Glock pulses from the pulse from the third waveform conversion circuit (6) to the pulse from the W42 waveform conversion circuit (5) are connected to the second waveform conversion circuit (5) and the third waveform conversion circuit (6). The time between these pulses
Calculated.

(10) indicates an arithmetic circuit that inputs signals from the counter circuit (7), the first time counting circuit (8), and the second time counting circuit (9); 2 hour counting circuits (8), (9) and arithmetic circuit (1
0) constitutes a calculation means (14), (11) is a setting device for setting predetermined items, (12) is a memory in which numerical values corresponding to each item are stored, and (13) is the calculation means described above. A display device for displaying the calculation results of the circuit (10) is shown.

Here, A is the cycle angle from the reference angle near the top dead center of the first cylinder to the next reference angle near the top dead center, as shown in FIG. 3(b), and A is the normal 4-cycle, 4ki~6%
If the cylinder engine is torn, it will be 360 degrees. If the angle between the pulses in FIG. 3(d) is Y, then Y=A/N, which remains unchanged even if the engine rotation changes as long as the engine is in a normal state. Time X in (f) of Figure 3
If the angle of is X, then X=(x/y)Y=(x/y)(
A/N) is established. Here, point B in Fig. 3 (b) may be slightly deviated from top dead center (C), and if the deviation angle is defined as Z before top dead center, the above formula is X = (x/y) (
A/N)+z needs to be corrected. Here this Z
The value of is known depending on each manufacturer or vehicle model.

The type of distributor of the engine of a car with an electronic advance device measured in this way (Fig. 3 (b) per crank rotation)
) is set in the setting device (11), and correction items corresponding to the manufacturer or model of the vehicle are set in the setting device (11). The value of A according to these items (if the point changes from positive to negative in Figure 3 (b) m times in one revolution of the crank, then
= 360/m. ) and Z value in memory (
12) and input it to the arithmetic circuit (10).

After performing this preliminary action, the input sides of the waveform conversion circuits (4) and (5) are connected to the pickup coils (1b) and (2b) of the automobile distributor, respectively, and the waveform conversion circuit (6) is connected to the pickup coils (1b) and (2b) of the automobile distributor. When the pickup coil on the input side is attached to the high voltage cord of the first cylinder of the engine and the simulated engine is driven, the arithmetic circuit (10) receives a signal corresponding to the value of N from the counter circuit (7). However, a signal corresponding to the value of y is also inputted from the first time counting circuit (8) to the first time counting circuit (8), so that X=(
X/Y)(A/N)+Z is computed, and the computed value of X is displayed on the display device (13).

Here, measurement errors occur due to fluctuations in engine rotation, but if y is measured immediately after measuring X in FIG. 3, there will be almost no measurement errors. When X' of the forked period is measured, the value of y' is used for calculation.

(7) Effects of the Invention As described above, according to the present invention, the calculation means calculates the angle corresponding to the time between the signal from the ignition timing detection means and the reference angle detection means based on the signal from the angle measurement means. A calculation is performed to correct the angle from the reference angle and the known correction angle between the first dead center, and the angle from the top dead center to the ignition timing, which is the result of the calculation, is displayed on the display means, so even if the surroundings are bright, it is accurate. It has the advantage that the ignition timing can be known immediately, and there are no measurement errors caused by different measurement personnel.

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is a plan view of the detection means for the rotation angle of the crankshaft and the reference angle near the top dead center of the cylinder, and Fig. 3 is the block diagram of the above-mentioned block diagram. It is an output waveform diagram of each block of a diagram.

(1)...Angle measuring means (2)...Reference angle detection means (3)...Ignition timing detection means (13) Display means (14)...Arithmetic means Math 2 diagram Figure 3 (d)-

Claims (1)

[Claims] A signal from an angle measuring means for measuring the rotation angle of the crankshaft of the engine, a signal from a reference angle detecting means for detecting a reference angle near the top dead center of a predetermined cylinder of the engine, and an ignition timing of the cylinder are detected. calculation means for calculating the rotation angle of the crankshaft from the top dead center of the cylinder to the ignition timing by inputting a signal from the ignition timing detection means;
An engine ignition timing measuring device comprising display means for displaying the calculation results.