JPH0329986B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine ignition control method, and particularly to improving ignition timing during rapid acceleration.

In recent years, with the rapid development of electronic technology, engine control has also become digital. For example, in an electronically controlled engine ignition control circuit,
An angle pulse generated every unit angle rotation of the crankshaft and a reference position pulse indicating the reference position of the crank are generated, and the angle pulses are counted based on the generation point of this reference position pulse. A count start signal is generated when a predetermined value is reached, that is, just before the ignition zone. When this count start signal is generated, the counter that counts the clock pulses starts counting and measures time, and the count value becomes 1.
The ignition timing is controlled by controlling the energization to the ignition coil at the time when the rotation speed reaches a value calculated based on the rotation speed before the cycle.

However, in the conventional engine ignition control circuit described above, the optimum ignition point is calculated based on the rotation speed one revolution before, and the clock pulse is counted based on the starting point of the ignition zone corresponding to this calculated value. Since the advance angle control is performed by performing the A delay in response to rotational fluctuations occurs. As a result, in extreme cases, ignition will occur outside the intended ignition zone, resulting in the problem that sufficient engine output cannot be obtained. In this case, the ignition zone is provided in synchronization with the cycle of the angle pulse, so if you try to make the gear for generating the angle pulse smaller, the number of teeth will decrease and the cycle of the angle pulse will become longer. As a result, a problem arises in which the responsiveness of the control to rotational fluctuations deteriorates.

Therefore, it is an object of the present invention to provide an engine ignition control system that improves the ignition timing during rapid acceleration of the engine to increase control accuracy, and also enables miniaturization of the gear provided for generating angular pulses. That's true. Hereinafter, it will be explained in detail using the drawings.

FIG. 1 is a circuit diagram showing an embodiment of an engine ignition control method according to the present invention. In the figure, 1 is a counter that sequentially counts the angle pulse A of, for example, 30° generated every unit angle rotation of the crankshaft and outputs the counted value n. It is reset by a reference position pulse B having a period six times as long (180 degrees) and indicating the reference position of the crankshaft. 2 is a rotation speed detection circuit,
By counting the clock pulses ₁ between the occurrences of the reference position pulses B, the engine rotational speed N is determined.
I'm looking for. 3 converts analog negative pressure signal C, water temperature signal D, and atmospheric pressure signal E supplied from negative pressure, water temperature, and atmospheric pressure sensors (not shown) into digital signals C', D', and E', respectively, and outputs the digital signals C', D', and E'. analog. Digital conversion circuit, 4 is count value n, rotation speed N, negative pressure signal C', water temperature signal D' and atmospheric pressure signal
A microcomputer that calculates the optimal ignition point, advance angle value α, and energization time control value β and performs various controls by performing various calculations using E' as input;
When reset by the reset signal RS ₁ supplied from the microcomputer 4, the counter 5 generates a count start signal F synchronized with the angle pulse, which inverts to "H" at the time when two angle pulses A are taken in. A count start signal generating circuit includes a counter 6 which is reset by a reset signal _RS1 and generates an output _Q1 to an output F, an inverter 7 which inverts the output _Q1 of the counter 6, and an output of the inverter 7. and an AND gate 8 which supplies the angle pulse A to the counter 6 as the clock CK only during the period when the clock is "H". 9 is the first latch circuit, which connects the data bus DB from the microcomputer 4 to
The advance angle value α supplied via the microcomputer 4 is latched when the latch signal _L1 supplied from the microcomputer 4 is generated. Reference numeral 10 denotes a second latch circuit which latches the energization time control value β supplied from the microcomputer 4 via the data bus DB at the time when the microcomputer 4 generates the latch signal _L2 . Reference numeral 11 denotes a first down counter which receives the latch output of the first latch circuit 9 as an input, and presets the input signal and starts the counting operation at the rising edge of the count start signal F generated from the count start signal generation circuit 5. and then subtract sequentially using clock pulse ₂ .
When the count value reaches zero, the output signal OUT becomes “H”
to be reversed. 12 is a second down counter which presets the latch output of the second latch circuit 10 in response to the rise of the output signal of the first down counter 11, starts counting operation, sequentially subtracts the clock pulse ₃ , and calculates the count. When the value reaches zero, the output signal OUT is inverted to "H". The output of the second down counter 12 is then supplied as an ignition control signal X to a power transistor that controls energization to an ignition coil (not shown). The operation of the circuit with the above configuration will be explained below using the flowcharts shown in FIGS. 2a to 3e.

In the circuit configured in this way, the reference position pulse B is generated as shown in Figure 2a, while the angle pulse A is generated with respect to the reference position pulse B as shown in Figure 2b. For example, it is generated as a signal having six times the frequency. And counter 1
is reset by the reference position pulse B and sequentially counts the falling edge of the angle pulse A.
~ The count value n of #6 is sent to the microcomputer 4.
supply to. In addition, the rotation speed detection circuit 2 counts the clock pulse ₁ between each period of the reference position pulse B, thereby calculating the rotation speed N ₁ per unit time,
N ₂ , N ₃ ...... are calculated sequentially. Furthermore, analog. The digital conversion circuit 3 converts the analog negative pressure signal C, water temperature signal D, and atmospheric pressure signal E supplied from each sensor into digital values C', D',
It converts it into E' and supplies it to the microcomputer 4. The microcomputer 4 calculates the optimum ignition timing by performing various calculations based on this information.

On the other hand, the ignition zone is predetermined, for example, as periods #5 and #6 of angle pulse A, as shown by Z in FIG. 2b. Then, the microcomputer 4 determines to what position of the angle pulse A within the ignition zone Z the previously calculated ignition timing belongs, and at the leading edge of the cycle of the angle pulse A to which this ignition timing belongs. A reset signal _RS1 is generated so that the count start signal F is inverted to "H".

In this case, the count start signal generation circuit 5
is configured to count two angle pulses A and invert the output, so the count start signal F is output at the leading edge of the period of the target angle pulse A.
In order to invert the signal to "H", it is sufficient to generate the reset signal _RS1 two cycles before.

Such operations are processed by the microcomputer 4 according to the flowchart shown in FIG. 3. When the microcomputer 4 starts when the power is turned on, initialization processing is performed in step _S1 . step after
The process moves to step _S9 via S ₂ , S ₃ , S ₄ , S ₅ , and S ₆ , and it is determined in what part of the ignition zone the ignition timing calculated here is located, that is, in what part of the angular pulse A. It is determined whether it is located in a periodic part. Next, when the count value n of counter 1 reaches #3, the process moves from step _S2 to step _S10 .
If the previously calculated ignition timing belongs to the #5 cycle of the angle pulse A, a reset signal _SR1 is generated in step _S11 and the counter 6 is reset. In this way, when the counter 6 is reset, the count start signal F output from the count start signal generation circuit 5 becomes the second
The signal is inverted to "L" as shown at time _t1 in FIG.

Next, when the count value n of the counter 1 reaches #4, the process moves from step _S3 to step _S12 , and it is determined whether the ignition timing belongs to the #5 period of the angle pulse A. In this case, since the ignition timing belongs to the #5 cycle, the process moves to steps S ₁₄ and S ₁₅ to calculate the advance angle value α and the energization time control value β, and the first and second latch circuits 9, A latch to 10 is performed. In this case, to latch the lead angle value α to the first latch circuit 9, the microcomputer 4 sends the lead angle value α as parallel data via the data bus DB, and in synchronization with this, the latch signal _L1 is generated. It is done by doing.
Similarly to the case described above, the energization time control value β is latched to the second latch circuit 10 by sending the energization time control value β as parallel data from the microcomputer 4 via the data bus DB, and synchronizing with this. This is done by generating the latch signal _L2 .

Next, when the count start signal generating circuit 5 inputs the generation of the reset signal _RS1 , in particular, the two angle pulses A, the generated count start signal F becomes the angle pulse as shown at time _t2 in FIG. 2c. It is inverted to "H" in synchronization with the fall of count value #4 at A, that is, the start of count value #4. When the count start signal F is inverted to "H", the first down counter 11 is switched to the first latch circuit 9.
The latch output _α1 is preset to invert the output signal G to “L” as shown in FIG. 2d, and
Start counting down clock pulse ₂ .
When the first down counter 11 finishes counting down the preset lead angle value α ₁ and its count reaches zero, the output signal G becomes “0” as shown at time t ₃ in FIG. Flips to "H". When the output signal G becomes “H”, the second down counter 12
presets the latch output _β1 of the second latch circuit 10, and the ignition control signal X as its output signal is inverted to "L" as shown in FIG.
Start counting down the clock pulse.
Here, when the ignition control signal X is reversed to "L",
Since the power transistor (not shown) is turned off and the current to the ignition coil is cut off, a high voltage is generated in the ignition coil, and ignition is performed during the period when the count value n of the counter 1 is #5. Therefore, the second
The "H" period of the ignition control signal X generated from the down counter 12 is the energization time, and the microcomputer 4 controls the energization time to be always constant by varying the energization time control value β. In this case, the counting period of the advance angle value α by the first down counter 11 is equal to the angle pulse A.
As a result, the ignition timing can be controlled with high accuracy even when the engine rotation suddenly changes.

Next, the ignition timing calculated by the microcomputer 4 is determined when the count value of the counter 1 is #6.
If it belongs to the period shown in FIG. 3, the flowchart shown in FIG. ₃ moves from step S3 to step _S12 and then to step _S13 . And this step S ₁₃
At this point, the counter 6 is reset and the count start signal F is inverted to "L". Next, in step _S4 , when it is detected that the count value n of the counter 1 has reached #5, the process moves to step _S16 , where the ignition timing is determined. In this case, since the ignition timing belongs to #6, the advance angle value α and the energization time control value β are calculated in steps S ₁₇ and S ₁₈ and the ignition timing is transferred to the first and second latch circuits 9 and 10. After the latching is performed, the ignition control signal X is inverted to "L" and becomes "L" within the period of count value #6, as shown at time _t4 in FIG. ignition takes place.

Here, the above explanation is for the case where the rotation of the engine does not suddenly change, but if the engine that is generating the reference position pulse B and angle pulse A in the states shown in Fig. 4 a and b is suddenly accelerated. The period of the reference position pulse B' and the angle pulse A' is shortened as shown in FIGS. 4c and 4d in response to the acceleration of rotation. In this case, in the conventional circuit,
In order to continue the ignition control operation based on the previous information regardless of sudden acceleration, the count start signal F, the output G of the first down counter 11, and the ignition control signal X are as shown in FIG. 4 e to g. As a result, the ignition time _t5 at which the ignition control signal X is inverted to "L" is delayed to the period when the count value n of the counter 1 is #6, making it impossible to perform optimal ignition.

On the other hand, in this embodiment, when the period #6 is detected in step _S5 of FIG. 3, the process moves to step _S19 and the ignition timing is determined. If the ignition timing is in period #5, it is determined that the ignition timing is relatively delayed due to sudden acceleration, and a reset signal _RS2 is generated in step _S20 . In this way,
When the reset signal _RS2 is generated at the start of #6, the first down counter 11 is reset to zero, so that the output signal G' becomes as shown in Fig. 4, as in the case at the end of counting. i is forcibly inverted to "H" as shown at time _t6 .

When the output signal G' is inverted to "H", the second reset counter 12 is preset and starts counting, and its output signal, that is, the ignition control signal X, is inverted to "L" to perform ignition control.

Further, when the ignition timing is in the period of count value #6, similar control is performed in steps S ₆ , S ₇ , and S ₈ of the flowchart shown in FIG. Ignition control is forcibly performed at the start point.

Therefore, in the circuit configured in this way, the period of the angle pulse A to which the calculated ignition timing belongs is calculated in advance, and if this ignition timing exceeds the calculated period, the engine is It is determined that the relative relationship has shifted due to sudden acceleration, and the ignition is forcibly ignited at the beginning of the next cycle of angle pulse A. As the ignition timing falls within the predetermined period, the amount of deviation in the ignition timing decreases. Therefore, the period of the angle pulse A can be relatively long, for example, 30 degrees, and accordingly, the gear that generates the angle pulse A can be made smaller by reducing the number of teeth. This makes it possible to reduce costs and incorporate it into a distributor.

In the above embodiment, a case has been described in which forced ignition is performed by forcibly resetting the first down counter, but the present invention is not limited to this. Any method may be used as long as it forcibly inverts the ignition control signal X to "L", presets the second down counter 12, and starts the counting operation.

As explained above, in the engine ignition control method according to the present invention, the cycle portion of the angular pulse to which the pre-calculated ignition timing belongs is determined, and the ignition timing is adjusted to the next cycle of the angular pulse as the engine suddenly accelerates. If there is a deviation in the ignition timing, the ignition is forcibly ignited at the start of the next period of the pre-calculated angle pulse period, so the amount of deviation in ignition timing during sudden acceleration is much smaller than before. will be significantly reduced. In addition, since the amount of deviation in the ignition timing is within the period of the angle pulse, the number of teeth on the gear used to generate the angle pulse can be reduced, and the cost is reduced due to the miniaturization of the gear. It has an excellent effect of allowing gears to be mounted inside the down and distributor.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram for explaining an embodiment of the engine ignition control method according to the present invention, and FIG. 2 a to e
1 is an operation waveform diagram of each part of the circuit shown in FIG. 1, FIG. 3 is a flowchart showing the operation of FIG. 1, and FIGS.
j is an operation waveform diagram of each part for explaining the operation of FIG. 1; DESCRIPTION OF SYMBOLS 1...Counter, 2...Rotation speed detection circuit, 3...Analog-digital conversion circuit, 4...Microcomputer, 5...Count start signal generation circuit, 6
... Counter, 7... Inverter, 8... AND gate, 9, 10... First and second latch circuits, 11, 1
2...First and second down counters.

Claims (1)

[Claims] 1 Optimized by microcomputer control by inputting a reference position pulse indicating the reference position of the crankshaft, a large angle pulse such as 30° generated every unit angle rotation of the crankshaft, and information such as negative pressure, water temperature, and atmospheric pressure. In an engine ignition control method in which the ignition timing is calculated to perform advance angle control and energization control to the ignition coil, the microcomputer calculates the cycle portion of the angular pulse to which the optimum ignition timing, calculated from the previous cycle of the ignition zone, belongs. If the ignition point exceeds this discrimination cycle, it is determined that a relative deviation has occurred due to sudden acceleration of the engine, and the ignition is forcibly ignited at the start of the next cycle of the angle pulse after the discrimination cycle. An engine ignition control method characterized in that the relative amount of ignition deviation during sudden acceleration is reduced by