JPH07101028B2 - Ignition timing control device - Google Patents

Description

The present invention relates to an ignition timing control device for electronically controlling the ignition timing of an engine.

[Conventional technology]

5 to 7 show a conventional ignition timing control device. In the figure, (1) is a crankshaft of a 4-cycle 4-cylinder engine, (2) is a disk fixed to this crankshaft and rotating with the rotation of the shaft, and 18 is on the circumference of the disk.
Magnetic bodies (3A) and (3B) are fixed at positions separated by 0 °. (4C) and (4D) are arranged close to the outer periphery of the disc (2) with a predetermined angular difference from each other, and when they face the magnetic body (3A) or (3B), the reference position pulse Pc , Pd for each electromagnetic pickup,
The electromagnetic pickup (4D) is provided to detect the crank angle position corresponding to the most delayed ignition timing in the ignition timing control angle range of the engine.
C) is provided at a position rotated 90 ° from the position of the electromagnetic pick-up (4D) along the outer peripheral direction of the disk 2, and the reference position pulses Pc and Pd alternate every time the crankshaft 1 rotates 90 °. It is configured to be delivered. (5) is an oscillator that outputs a clock pulse CP, (6) is the oscillator (5)
A cycle measuring means for measuring the time interval Tc of the reference position pulse Pc based on the clock pulse CP of the crankshaft, and (9) a crank to be detected by the electromagnetic pickup (4D) based on the information S such as the engine speed and the manifold pressure. An ignition timing calculation means for calculating an ignition advance angle value θ with reference to the reference position of (20) is a basic energization time Tl required for the primary current of the ignition coil (42) to reach a predetermined value from the battery voltage U. Basic energization time calculation means for calculating
It is an ignition time calculation means for inputting Tc and the ignition advance angle θ, and calculating and outputting a time Ts until the ignition after the reference position pulse Pc is sent out in synchronization with the reference position pulse Pc by a method described later. From this time Ts and the basic energization time Tl of the ignition coil (42), the energization start time calculating means (21) obtains the time Toff from the generation of the reference position pulse Pc to the start of energization of the ignition coil (42), and the energization command output means (22) inputs the clock pulse CP, the reference position pulse Pc, and the energization start time Toff, and the ignition coil (42) after the start time Toff has elapsed from the generation of the reference position pulse Pc.
An energization command signal Pon for starting energization is output. The first ignition command output means (30) for inputting the time Ts output from the ignition time calculation means (10), the clock pulse CP, and the reference position pulse Pc is the time Ts from the time when the reference position pulse Pc is input. When the time elapses, an ignition command signal Pspk for interrupting the current of the ignition coil (42) is generated. On the other hand, the second ignition command output means (31) generates the second ignition command signal Psd in synchronization with the input of the reference position pulse Pd. The ignition control signal output means (40) inverts the electrical state from the “L” level to the “H” level in synchronization with the energization command signal Pon, and outputs the first ignition command signal Pspk or the second ignition command signal Psd. Either the electrical state is set to "H" in synchronization with the signal generated earlier in time.
It is composed of an ignition control signal output means (40) for sending out an ignition control signal Ps which is inverted from the level to the "L" level, and the ignition device (41) is activated by this ignition control signal Ps to operate the ignition coil (42). Drive and ignite the engine.

Now, when the reference position pulse Pc sent from the electromagnetic pick-up (4C) is sequentially Pc1, Pc2, Pc3 (Fig. 6a), the period measuring means (6) changes to the clock pulse CP of the reference oscillator (5). Based on the reference position pulse Pc2, input P
The pulse period Tc2 of c1 and Pc2 is time-measured.

When the reference position pulse Pc2 is sent, the ignition time calculation means (10) obtains the time interval Tc and the time Ts2 (FIG. 2c) from the ignition advance value θ to the next ignition time by the following equation.

As described above, the first ignition command output means (30) outputs the ignition command signal, which is the current cutoff timing of the ignition coil (42), after the time Ts2 obtained by the equation (1) has elapsed from the generation of the reference position pulse Pc2. Generates Pspk2.

Ignition coil (42) in the ignition cycle corresponding to this ignition
The energization start is calculated by the energization start time calculating means (21) as the time Toff from the generation of the reference position pulse Pc2 to the energization start. That is, the energization start time calculation means (21) calculates the basic energization time Tl calculated by the basic energization time calculation means (20) from the time Ts from the reference position pulse Pc previously calculated by the ignition time calculation means (10) to the ignition. Subtraction start time
Calculate Toff.

Toff = Ts-tl (2) The energization command output means is activated at the time when the reference position pulse Pc is generated, and the energization command signal (the sixth value) is passed after the energization start time Toff has elapsed.
Figure d) is generated. The ignition control signal output means (40) starts energizing the ignition coil (42) when the energization command signal Pon is input, and is synchronized with the first ignition command signal Pspk or the reference position pulse Pd (Fig. 6b). Second ignition command signal Ps
An ignition control signal Ps (Fig. 6f) for interrupting the current of the ignition coil (42) and igniting the engine is generated by the ignition command signal of whichever is earlier than d (Fig. 6e). .

The ignition timing control device of FIG. 5 is configured as described above, the time interval TC of the reference position pulse Pc is constant when the engine rotation is constant, and the first ignition command signal Pspk is the second ignition command signal Psd. Ignition is performed by the first ignition command signal Pspk because it occurs earlier. Further, at the time of acceleration as shown in FIG. 7, the engine rotation increases with each ignition, and the time interval Tc of the reference position pulse PC decreases with each ignition.
The time interval of the actual reference position pulse PC becomes shorter than the time TC used when the ignition time Ts is calculated by the formula. Therefore, when the ignition advance value θ is close to O, the second ignition command signal Psd (Psd in FIG. 7C) is output from the first ignition command signal Pspk (FIG. 7C).
(Fig. 7e) occurs first, and ignition is issued. Ignition command Psd for 2
That is, the ignition control signal Ps is configured to be performed in synchronization with the reference position pulse Pd. (Fig. 7f). This prevents the ignition from being delayed from the reference position pulse Pd even in the acceleration state.

If there is no ignition due to this second ignition command signal Psd,
If ignition is performed only by the ignition command signal Pspk of, the ignition command signal Pspk will be generated at a time substantially later than the second reference position pulse Pd during acceleration, and the engine will be retarded at an abnormally retarded position. Ignition occurs and problems such as engine output drop occur.

In this way, in order to realize the ignition control with good response even during acceleration in this kind of ignition timing control device, it can be said that the ignition restriction by the second ignition command signal Psd is a suitable method.

[Problems to be Solved by the Invention]

By the way, the ignition timing control device of FIG.
Although the abnormal retardation is prevented by the ignition command signal Psd, the energization of the ignition coil (42) is started as it is before the first energization time Tl from the first ignition command signal Pspk.
Therefore, under the condition that after the start of energization by the energization command signal Pon, the second ignition command signal Psd which is generated earlier than the first ignition command signal Pspk is ignited, The typical energization time is shorter than the basic energization time Tl.
(Ps2 in Fig. 7f) For example, in normal operating conditions, the most drastic change in rotation speed occurs when racing from the idle state, and at 1 rpm around 1000 rpm.
The number of revolutions increases by about 100 rpm in the ignition cycle. In the ignition timing control device of FIG. 5, the shortage of energization time is most noticeable when the ignition advance value θ is 0. In the above racing state, the ignition time Ts at 1000 rpm (Tc = 15 ms) is (1 From the formula), Ts = 15 (ms) is calculated. On the other hand, if the rotation of the engine uniformly increases at a rate of 100 rpm in the one ignition cycle, the time Tcd from the generation of the reference position pulse PC to the second ignition command signal Psd is about 14.3 (ms), and Tcd-Ts ≒
A time difference of 0.7 (ms) occurs and the energization time is short of 0.7 (ms).

In particular, in engines that have been set to a high maximum speed, such as the recent DOHC engine, in order to secure the output voltage in the high speed range, the primary current rises quickly so that the specified secondary output can be obtained in a short energization time. Ignition coils are used. For example, in an ignition coil with a basic energization time Tl of 3 (ms), the secondary output voltage is 2 even if the energization time of only 0.7 (ms) is insufficient.
It may decrease by about 5% and may cause engine performance deterioration and breathing due to misfire.

No matter how accurately the basic energization time calculation means (20) calculates the basic energization time Tl required to obtain a predetermined secondary output, the ignition coil energization time is inevitably short because it is reduced during acceleration.

The present invention has been made to solve the above-described problems, and prevents the occurrence of an abnormal retardation of the ignition timing when the engine speed increases due to acceleration, and prevents the ignition coil from igniting due to an insufficient energization time of the ignition coil. An object of the present invention is to provide an ignition timing control device that prevents a shortage of the next output voltage.

[Means for Solving the Problems]

The ignition timing control means according to the present invention comprises an energization time correction means for correcting the energization time of the ignition coil primary current according to the rotation cycle of the engine.

[Action]

According to the present invention, since the energization time of the ignition coil primary current is corrected according to the rotation cycle of the engine, a sufficient secondary voltage can always be obtained.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In FIG. 1 in which the same parts as those in FIG. 5 are designated by the same reference numerals, (23) is a basic energization time calculating means (20).
It is an energization time correction means for determining the energization time of the ignition coil (42) by correcting the basic energization time Tl of the ignition coil (42) calculated in step 1 according to the measurement cycle Tc of the cycle measuring means (6).

The energization time correction amount ΔT calculated by the energization time correction means (23) is set so that the energization time of the ignition coil responds sufficiently to the acceleration of the rotation speed increase of 100 rpm in one ignition cycle described above, and It is calculated by the following equation (3) so that the power consumption of the ignition device and the heat generation of the ignition coil are not increased by increasing the correction amount more than necessary.

This formula (3) shows that when the engine speed obtained from the cycle Tc when the energization time is set is Ne (rpm), the engine
Assuming that the number of revolutions increases by Ne + 50 (rpm) during ignition after 0 ° rotation, the shortage time Δt without energization time correction is calculated as follows, and the correction amount ΔT is set to compensate for this shortage time. It has been set.

FIG. 3 shows the energization time correction amount ΔT in terms of the ratio of time to one ignition cycle Tc. The correction rate is smaller in the higher rotation range, and on the contrary, the correction rate is higher in the low rotation range.

The basic energization time Tl is corrected by this correction amount ΔT, and the actual energization time control value becomes Tl + ΔT.

Therefore, the energization start time that determines the energization start timing of the ignition coil (42) is expressed by the following equation (4).

Toff = Ts- (Tl + ΔT) (4) FIG. 2 shows the operation during acceleration according to the present embodiment.
Since the energization start time is advanced by ΔT (FIG. 2c), the ignition control signal Ps can secure a sufficient energization time even if ignition is performed at Psd. (Fig. 2f) With this correction, 1 (1 ignition cycle at around 1000 rpm)
Considering the state where the number of revolutions increases at 00 rpm, the correction amount ΔT of the energization time is 0.7 (ms) from the equation (3), and the lack of the energization time of 0.7 (ms) can be compensated.

As described above, according to the equation (3), it is possible to compensate for the lack of the energization time over the entire engine rotation range and to prevent the engine malfunction due to the lack of the secondary output voltage.

Although the correction formula (3) is simple as a formula, if it is attempted to perform this calculation by a low-level microcomputer, it may take a processing time to execute the multiplication, which may cause a problem in the S / W structure.

Therefore, equation (3) may be approximated by an equation that is easier to calculate.
For example, by using the following equation (5), it is possible to correct the shortage of energization time under the above-described acceleration condition in the engine speed range of 500 rpm to 2200 rpm.

The energization time correction amount ΔT is shown in FIG. 4 when expressed as a rate of time for one ignition cycle Tc, as in FIG. 3 relating to the equation (3).

In addition to these equations, an equation that corrects the energization time shortage for engine acceleration by the engine rotation cycle is conceivable. There is a difference in the degree of acceleration depending on the engine model, and even if an optimum energization time correction formula is provided for each engine, it does not affect the essence of the present invention. The engine rotation cycle used for this energization time correction may be the rotation cycle predicted by measuring the cycle between different predetermined rotation angles of the engine and increasing or decreasing the cycle.

Further, in order to detect the crank reference angular position, in the above-mentioned embodiment, two detectors of magnetic pickup (4C) and (4D) are used. Two crank reference positions may be detected using an angle detector that changes from a high level to a low level at position Pd, and one magnetic pick-up may be used to chronologically determine both reference positions Pc and Pd. It may be configured to detect and determine Pc and Pd by a detector other than this.

[Advantages of the Invention] As described above, according to the present invention, the energization time required for the pre-calculated ignition coil to generate a predetermined secondary output voltage is increased and corrected in accordance with the engine rotation cycle. Also, there is no shortage of energization time even when the rotation cycle is reduced during acceleration, and therefore it is possible to prevent the occurrence of engine performance deterioration and breathing phenomenon due to insufficient secondary output voltage of the ignition coil. is there.

[Brief description of drawings]

FIG. 1 is a block diagram of an ignition timing control device according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of FIG. 1, and FIGS. 3 and 4 show the operation of FIG. Characteristic diagram to explain, No. 5
FIG. 6 is a block diagram of a conventional ignition timing control device, No. 6
FIG. 7 and FIG. 7 are waveform charts for explaining the operation of FIG. 1 ... Crank shaft, 2 ... Disc, 3A, 33 ... Magnetic material, 4C,
4D: Electromagnetic pickup, 5 ... Oscillator, 6 ... Cycle measuring means, 9 ... Ignition timing calculation means, 10 ... Ignition time calculation means, 20 ... Basic energization time calculation means, 21 ... Energization start time calculation Means, 22 ... energization command output means, 23 ... energization time correction means, 30 ... first ignition command output means, 31 ... second
Ignition command output means, 40 ... Ignition control signal output means, 41
...... Ignition device, 42 ...... Ignition coil

Claims (1)

[Claims] 1. A reference position detecting means for generating a reference position signal at a predetermined crank angle position of an engine, a rotation cycle measuring means for obtaining a rotation cycle of the engine based on the reference position signal, and a primary current of an ignition coil in advance. Based on the rotation cycle and the ignition timing, a basic energization time calculating means for obtaining a basic energization time required to reach a predetermined value, an ignition timing calculating means for calculating an ignition timing according to the operating state of the engine, Ignition time calculating means for calculating an ignition time from the reference position to the ignition timing, and an energization start time from a predetermined reference position to the ignition coil energization start timing based on the ignition time and the ignition coil energization time. Energization start time calculating means and an energization finger that generates an energization command signal for starting energization of the ignition coil after the energization start time has elapsed from the time point of the predetermined reference position. Output means, an ignition command output means for generating an ignition command signal for interrupting the energization of the ignition coil after the ignition time has elapsed from the time when the reference position signal was generated, and an ignition command for starting the energization of the ignition coil by the energization command signal. And a ignition control signal output means for outputting to the ignition device an ignition control signal for interrupting the energization of the ignition coil by a signal, the basic energization time is corrected in accordance with the rotation cycle of the engine to determine the energization time of the ignition coil. An ignition timing control device comprising an energization time correction means for determining.