JPS6278476A - Control method for ignition timing of 4-cycle engine - Google Patents

Abstract

PURPOSE:To prevent production of ineffective spark and to provide an increased life for an ignition plug, by a method wherein delay angle correction is made on an ignition timing signal based on either an even number-th or an odd number-th pulse, and through observation of a change in the subsequent rotation speed of an engine, an ignition device is controlled. CONSTITUTION:When, with an engine started, an ignition timing foundation signal (pulse signal) is generated from a pickup coil 1, a control part 3 first detects the rotation sped of an engine from the signal to calculate an ignition timing. Thereafter, delay angle correction is made on the ignition timing foundation signal based on either an even number-th or an odd number-th pulse out of the pulse signals, and an ignition device 2 is controlled by means of an ignition timing signal after correction. When the rotation speed of an engine is decreased, the pulse on which delay angle correction is made is selected, meanwhile, when there is no change in the rotation speed of an engine, the pulse on which no delay angle correction is made is selected, and hereafter, the selected signal produces a foundation signal by means of which the ignition device 2 is controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling ignition timing of a four-stroke engine, particularly a four-stroke engine mounted on a two-wheeled vehicle.

[Conventional technology]

4-cycle engines in motorcycles usually do not have a distributor to reduce weight or simplify the structure, and the basis for determining ignition timing is a signal from a pickup coil, etc. that generates one pulse per crankshaft revolution. It is used as a signal.

Therefore, the original effective ignition occurs at compression top dead center, and an ineffective spark is generated at exhaust top dead center.

[Problem that the invention seeks to solve]

However, there is a problem in that such invalid sparks shorten the life of the spark plug. In addition, during high-speed rotation, which consumes a lot of ignition energy, energy loss due to reactive sparks is considerable, and in order to offset this energy loss and still generate sufficient effective sparks, a power supply means with a considerably large capacity is required. is required. Increasing the capacity of power supply means leads to larger and heavier equipment2.
This is a major drawback for wheeled vehicles.

Means for Solving Problem C] The ignition timing control method of the present invention has been made in view of the above problems, and is performed by controlling the even-numbered or odd-numbered pulses of the pulses synchronized with the rotation of the engine crankshaft. The ignition timing signal based on either one is retarded, and the ignition system is driven by this ignition timing signal. When the engine rotation speed decreases, the retarded pulse is selected to prevent changes in engine rotation speed. If there is no retardation correction, the pulse without the retardation correction is selected, and thereafter the ignition device is driven based on the selected pulse.

[Effect]

If the ignition timing signal at the compression top dead center is retarded, the engine output will decrease, but even if the ignition timing signal at the exhaust top dead center is retarded, the engine output will not change because it is originally an invalid ignition. Therefore, if you drive the ignition system by retarding the ignition timing signal based on either the even-numbered pulse or the odd-numbered pulse, and look at the change in engine speed at that time, you will see that either the even-numbered pulse or the odd-numbered pulse is compressed. It can be determined whether this is the basis for the ignition timing signal at top dead center. Thereafter, if the ignition device is driven based on the pulse selected based on this determination result, no invalid spark will be generated.

〔Example〕

Hereinafter, the present invention will be described in detail along with examples.

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing an apparatus for executing the flowchart of FIG. 1, and a waveform diagram showing various signals of FIG. 3.

The pickup coil 1 rotates once the crankshaft of a 4-cycle engine (360'
), and this output signal becomes the basic signal for determining the ignition timing. The ignition device 2 is a full transistor type ignition device that receives energy from a battery (not shown) through a terminal 4 to ignite the ignition device, and operates the ignition coil drive circuit 21 at the timing of an ignition timing signal from the control unit 3. to generate high voltage on the secondary side of the ignition coil 22, and the spark plug 23
It generates sparks.

In such a configuration, when the engine is started, the pickup coil 1 generates an ignition timing basic signal as shown in FIG. 3(A), so the control section 3 first reads this pulse signal (step 101). . After detecting the engine speed based on this pulse signal (step 102), the ignition timing is calculated (step 1o3).
). Here, the engine rotation speed is the pickup coil 1
It can be detected by measuring the period of the output pulse. In addition, in calculating the ignition timing, the output pulse of the pickup coil 1 is advanced in accordance with the engine rotational speed in order to perform ignition at the time when the engine output reaches its maximum. Figure 3 (B) shows the ignition timing signal created based on this calculation result.
) is delayed by one hour from the ignition timing basic signal. However, since this ignition timing signal is a pulse for each crankshaft rotation (360 degrees), effective sparks and ineffective sparks are generated alternately.

Next, the control unit 3 determines whether the test end flag is set (step 104). This test end flag will be described later, but since no test end flag is set at this stage, the process proceeds to step 105.

In step 105, it is determined whether the output pulse of the pickup coil 1 read in step 101 is for the n-th test ignition, and then in step 106, it is determined whether or not it is an odd-numbered pulse. Note that n is predetermined to be a value equivalent to about 1 second during idling rotation. now,
Assuming that the first pulse a1 has just been read, the process proceeds from step 106 to step 107, where the ignition timing signal b1 is retarded and the corrected ignition timing signal CI is output to the ignition device 2. Then, the process returns to step 101 again and the output pulse a2 of the pickup coil 1 is read. Next, the process goes through steps 102 to 105 and then proceeds to step 106 to step 108, where the ignition timing signal b2 is directly output to the ignition device 2 without being retarded. By repeating the same process below,
An ignition timing signal in which only the odd-numbered pulses are retarded and corrected as shown in FIG. 3(C) is generated and output to the ignition device 2.

At the time when the output pulse of the n-th pickup coil 1 is read, the process moves from judgment 105 to steps 109 to 110. Here, in step 109, a test lure flag is first set, and then in step 110, a change in engine speed is checked. Here, the engine rotation speed is shown in Figure 3 (D
), it can be said that the even numbered pulses are the basis of the ignition timing signal at compression top dead center; It can be said that this is the basis of the ignition timing signal at compression top dead center.Therefore, if the engine speed is not changing as shown by the broken line, set the even flag, and if it has changed, set the even flag. In this embodiment, it is assumed that the engine rotational speed has changed, and the even number flag is not set.

When the process returns to step 101, the output of the pickup coil 1 is read again, and when the process returns to step 104, the test end flag has already been set at step 109, so the process moves to step 112. As described above, since the even number flag is not set, the process moves to steps 115 and 116. In step 115, it is determined whether the output pulse of the big amplifier coil 1 that has just been read is an odd-numbered pulse, and if it is an odd-numbered pulse, an ignition timing signal is output according to the ignition timing calculated in step 103, and even If it is the second pulse, no ignition timing signal is output. Thereafter, steps 101 to 104, 112, 1
By repeating steps 15 and 116, the ignition timing signal output from the control unit 3 to the ignition device 2 becomes as shown in FIG. Does not produce sparks.

Note that if it is determined in step 110 that the engine speed has not changed, the even flag is set, so the process moves from step 112 to steps 113 and 114, and thereafter steps 101 to 1β4, 112, 113
．． By repeating step 114, an ignition timing signal based only on even-numbered pulses is created as shown in FIG. I won't let you.

In this embodiment, the reference pulse for the even-numbered pulses or the odd-numbered pulses can be arbitrarily determined. Furthermore, in this embodiment, the number of test ignitions n is determined so that the time '' for determining the engine speed is about 1 second, but this time may be selected as appropriate depending on the engine to which the present invention is applied. .

Furthermore, in this embodiment, the pulse that becomes the ignition timing signal at compression top dead center is determined based on the change in engine speed when the odd-numbered pulse is retarded, but the even-numbered pulse is It is also possible to perform the retardation correction for the odd-numbered (or even-numbered) pulses for determination, and then for confirmation, perform the retardation correction for the even-numbered (or odd-numbered) pulses. It is also good to perform angle correction for discrimination.

Furthermore, although this embodiment has been described for a single-cylinder engine, the present invention can be similarly applied to a multi-cylinder engine.

Furthermore, although it is desirable to carry out the present invention after the engine rotational speed becomes stable, any method may be used to detect the stable state in that case.

〔Effect of the invention〕

As explained above, according to the ignition timing control method of the present invention, the ignition timing signal based on either the even-numbered pulse or the odd-numbered pulse is retarded to drive the ignition device, and the engine rotational speed at that time is By observing the change in , it is determined whether an even number or an odd number of pulses forms the basis of the ignition timing signal at compression top dead center, and thereafter the ignition device is driven based on the pulse selected based on this determination result. So no invalid spark occurs. Therefore, the life of the spark plug is extended, and since there is little energy loss, the energy consumption for ignition is low even during high speed rotation, and therefore the power supply capacity etc. can be reduced.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing an apparatus for carrying out the embodiment of FIG. 1, and FIG. 3 is a waveform diagram showing various signals. 1...Pickup coil, 2...Ignition device, 3.
...Control unit. Patent applicant: Yamaha Motor Co., Ltd. Agent: Masaki Yamakawa (and 2 others) Figure 2 Figure 3

Claims (1)

[Claims] In a four-stroke engine equipped with an ignition device that uses pulses synchronized with the rotation of the engine crankshaft as the basis for ignition timing, the ignition timing is based on either the even-numbered or odd-numbered pulses among the pulses when the engine starts. The ignition timing signal is retarded, and the ignition device is driven by this ignition timing signal. If the engine speed decreases, the retarded pulse is selected, and if there is no change in the engine speed, the ignition timing signal is retarded. An ignition timing control method characterized by selecting the uncorrected pulse and thereafter driving the ignition device based on the selected pulse.