JPH0579436A - Ignition device of internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an internal combustion engine ignition device which can prevent over spark advance even on deceleration during start of an internal combustion engine in the case of using over-current cut-off circuit. CONSTITUTION:An over-current cut-off circuit 7 makes a power transistor 5 'off' compulsively and cuts off primary current of an ignition coil 10 when primary current value of the ignition coil 10 exceeds over-current set value. CPU 4 detects deceleration of an internal combustion engine at starting condition of the internal combustion engine, and it starts current carrying by making the power transistor 5 'on' at a fixed timing by a rotation angle sensor 8 and ends current carrying by making the power transistor 5 'off' at trailing edge of pulse signals except the deceleration time in the starting condition of the internal combustion engine. During the deceleration in the starting condition of the internal combustion engine, the power transistor 5 is made 'on' at the trailing edge of the pulse signals, and the power transistor 5 is made 'off' when minimum current carrying time corresponding to power supply voltage of the ignition coil 10 has passed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine ignition device,
A power transistor is provided in the primary coil of the ignition coil. As shown in FIG. 10, when the internal combustion engine is started, the pulse signal N from the rotation angle sensor is input and the power transistor is turned on by the ignition signal IGt synchronized with this signal.・ It is turned off and ignited by the spark plug. Further, the device is provided with a constant current circuit for protecting the power transistor, and the constant current circuit suppresses the current flowing through the power transistor to a predetermined value or less.

Then, it is conceivable to use the overcurrent interruption circuit shown in Nippon Denso Koho Giho 31-258 instead of the constant current circuit for protecting the power transistor. As shown in FIG. 10, this overcurrent cutoff circuit forcibly turns off the power transistor to cut off the primary current of the ignition coil when the primary current value It of the ignition coil exceeds the overcurrent set value Ito. is there. The overcurrent cutoff circuit is less expensive than the constant current circuit and can prevent heat generation of the power transistor.

However, when the overcurrent cutoff circuit is adopted in the system in which the ignition is performed by the ignition signal IGt synchronized with the pulse signal N from the rotation angle sensor, the primary current value It of the ignition coil exceeds the overcurrent set value Ito. In that case, the transistor is forcibly turned off (cut off), and as shown in FIG. 10, an overadvance occurs by θ1.

Therefore, as indicated by the ignition signal IGt 'in FIG. 10, the energization is carried out when a predetermined time To has passed from the rising edge of the pulse signal N from the rotation angle sensor (when the countdown reaches zero). A method of starting and ending energization at the falling edge of the pulse signal N can be considered. This energization time TON (that is, the predetermined time To) is set based on the previous pulse-on time TDWL.

[0006]

However, at the time of deceleration of the internal combustion engine of FIG. 10, the energization start time (countdown time) T from the rising edge of the pulse signal at this time is given.
Since o is set based on the previous pulse-on time TDWL, the energization time To 'during deceleration becomes longer, the overcurrent cutoff circuit operates, and the over-advance angle occurs by θ2.

Therefore, an object of the present invention is to provide an ignition device for an internal combustion engine which can prevent an over-advanced angle even during deceleration at the time of starting the internal combustion engine when an overcurrent cutoff circuit is used.

[0008]

According to the present invention, a rotation angle sensor for detecting a rotation angle of an internal combustion engine, a power transistor for controlling a primary current of an ignition coil, and a primary current value of the ignition coil are set to an overcurrent set value. When it exceeds, an overcurrent cutoff circuit that forcibly turns off the power transistor to cut off the primary current of the ignition coil, a deceleration detection unit that detects deceleration of the internal combustion engine in the starting state of the internal combustion engine, and the deceleration detection unit. Except during deceleration in the internal combustion engine starting state, the power transistor is turned on at a predetermined timing by the rotation angle sensor to start energization, and the power transistor is turned off at a reference crank angle near top dead center. When the internal combustion engine is decelerated by the deceleration detecting means and the deceleration detecting means when the internal combustion engine is in a starting state, the rotation angle sensor detects a value near the top dead center. An ignition device for an internal combustion engine, comprising: a second control means for turning on the power transistor at a quasi crank angle and turning off the power transistor at least when an energization time corresponding to the power supply voltage of the ignition coil has elapsed. To do.

Further, if the energization time of the ignition coil when the energization is completed at the reference crank angle is shorter than the minimum energization time for securing the ignition energy, the first control means makes the reference crank angle. It is preferable to continuously energize after passing through to ensure the minimum energizing time.

[0010]

The first control means turns on the power transistor at a predetermined timing by the rotation angle sensor to start energization except when decelerating the internal combustion engine by the deceleration detecting means in the starting state, and the top dead center is reached. At a reference crank angle in the vicinity, the power transistor is turned off to terminate the energization. In addition, when the deceleration is detected in the starting state of the internal combustion engine by the deceleration detecting means, the second
The control means turns on the power transistor at the reference crank angle near the top dead center by the rotation angle sensor, and turns off the power transistor at least when the energization time corresponding to the power supply voltage of the ignition coil has elapsed.

That is, during deceleration of the internal combustion engine in the starting state, the second control means energizes for a predetermined time, and the overcurrent cutoff operation of the overcurrent cutoff circuit due to the lengthening of the energization time causes an overcurrent cutoff operation. The advance angle can be avoided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of an ignition device for an internal combustion engine mounted on an automobile in this embodiment. An electronic control unit (hereinafter, referred to as ECU) 1 includes a waveform shaping circuit 2, an A / D exchanger 3, a central processing unit (hereinafter, CPU).
4), a power transistor 5, a resistor 6 and an overcurrent cutoff circuit 7. The rotation angle sensor 8 detects the rotation of the internal combustion engine and outputs a rotation angle signal at a predetermined rotation angle position. The rotation angle signal from the rotation angle sensor 8 is converted into a rectangular wave by the waveform shaping circuit 2 of the ECU 1 and taken into the CPU 4 as the pulse signal N shown in FIG.
The falling edge of the pulse signal N is near the top dead center (TDC) of the internal combustion engine. The sensor group 9 detects the state of the internal combustion engine. Then, the output signal of the sensor group 9 is converted into a digital value by the A / D exchanger 3 of the ECU 1 and taken into the CPU 4.

A battery voltage VB (12 volts) is applied to the primary coil and the secondary coil of the ignition coil 10, and an ignition plug 11 is connected to the secondary coil.
The overcurrent cutoff circuit 7 of the ECU 1 is a D flip-flop 12
And AND circuit 13, comparator 14, resistors 15, 16, 17
It consists of and. The ignition signal IGt (see FIG. 2) from the CPU 4 is input to the CK terminal of the flip-flop 12. A predetermined voltage Vr (5 volts) is applied to the D terminal of the flip-flop 12. Further, the CK terminal and the Q terminal of the flip-flop 12 are connected to the AND circuit 13
Of the AND circuit 13 and the output terminal of the AND circuit 13 is connected to the base terminal of the power transistor 5 via the resistor 6. The power transistor 5 and the resistor 15 of the overcurrent cutoff circuit 7 are connected in series to the primary coil of the ignition coil 10. The primary current of the ignition coil 10 is controlled by turning on / off the power transistor 5. The connection point a between the power transistor 5 and the resistor 15 is connected to the non-inverting input terminal of the comparator 14.
Further, the predetermined voltage Vr (5 volts) is divided by the resistors 16 and 17, and the connection point b between the resistors 16 and 17 is connected to the comparator 14.
It is connected to the inverting input terminal of. The output terminal of the comparator 14 is connected to the CLR terminal of the flip-flop 12.

The ignition signal IGt from the CPU 4 controls the power transistor 5 to be turned on / off via the AND circuit 13, and when the power transistor 5 is turned on, a current flows through the primary coil of the ignition coil 10. The primary current value It is detected by the resistor 15, the voltage value at the connection point a and the voltage value at the connection point b are compared by the comparator 14, and the primary current value It is determined as the overcurrent predetermined value Ito. When it becomes larger, the output of the comparator 14 becomes high level, and the level of the Q terminal of the flip-flop 12 becomes low. as a result,
The output of the AND circuit 13 becomes low level and the power transistor 5 is turned off regardless of the content of the ignition signal IGt. That is, when the primary current value It of the ignition coil 10 exceeds the overcurrent setting value Ito, the power transistor 5 is forcibly turned off to interrupt the primary current of the ignition coil 10.

The ECU 1 also inputs a switch signal (not shown) (for example, an idle switch or a neutral switch), and takes in the signal level-converted by the I / O circuit to the CPU 4. Then, the CPU 4 outputs an ignition signal IGt, an injection signal (not shown), and the like. still,
The injector drive circuit and the like are not shown in FIG.

Next, the output processing of the ignition signal IGt in the CPU 4 will be described by taking a 4-cylinder engine as an example. Hereinafter, description will be made with reference to the timing chart of FIG. FIG. 4 shows the processing of the main loop.

First, the CPU 4 calculates the battery voltage VB, the engine speed, etc. in step 100, and then executes step 1
In 01, the map is used to calculate the energization time TON according to the battery voltage VB. Then, the CPU 4 executes step 10
In step 2, the minimum energization time TONG is calculated by multiplying the energization time TON by 3/4. This minimum energizing time TONG
Is the minimum energization time for securing the ignition energy by the primary coil of the ignition coil 10. Furthermore, CP
U4 calculates the fuel injection amount, ignition timing, etc. in step 103. Such processing is repeated in the main loop.

FIG. 5 shows an interrupt activated in synchronization with the rising edge (NON) of the pulse signal N. That is,
It starts at the timing of t1, t3, t5, t7 in FIG. In step 200, the CPU 4 subtracts the pulse falling time from the pulse rising time of the pulse signal N to calculate the pulse off time TBDWL of the pulse signal N.
Further, in step 210, the CPU 4 determines whether or not the startup state determination flag XSTA is "1". If XSTA = 1, it is determined that the engine is in the startup state, and in step 220, the startup process to be described later is performed and the interrupt process is completed. On the other hand, CPU4 is XS
If TA = 0, it is determined that the engine is not in the starting state, and the normal processing is performed in step 230 to end the interrupt processing.

FIG. 6 shows the start-up process of step 220. CPU4 compares whether the pulse-off time TBDWL _i of the current pulse signal at step 221 is longer than the pulse off time TBDWL _i-1 of the previous pulse signal, a deceleration determination flag XSGEN at step 222, if not the deceleration is shorter "0" Then, in step 223, t in FIG.
As indicated by 1, t3 and t5, the energization start is set so that the energization is started when the time TDON (= TDWL-TON) has elapsed from the occurrence of the rising edge of the pulse signal N, and the interrupt process is ended. As a result, t1 and t in FIG.
The countdown is started at the timing of 3, t5 and the ignition signal IGt is raised at the timing of t1a, t3a, t5a where the count value becomes zero. TDW
L is the immediately preceding pulse-on time, which will be described later in step 310.
Described in.

If the current pulse-off time TBDWL _i is longer than the previous pulse-off time TBDWL _i-1 in step 221 of FIG. 6, the CPU 4 determines that the vehicle is decelerating (timing t7 of FIG. 2), and in step 224, the deceleration determination flag is set. Set XSGEN to "1" and exit the interrupt.

FIG. 7 shows an interrupt process activated in synchronization with the falling edge (NOFF) of the pulse signal N. That is, it starts at the timing of t2, t4, t6, t8 in FIG.

In step 300, the CPU 4 obtains 180 ° A time (T180) equal to the ignition cycle. That is, the previous pulse fall time is subtracted from the pulse fall time of the current pulse signal N to obtain 180 ° C. A time (T18
0) is calculated. Further, in step 310, the CPU 4 subtracts the pulse rising time from the pulse falling time of the pulse signal N to obtain the pulse ON time TD of the pulse signal N.
Calculate WL. Then, the CPU 4 checks the starting state determination flag XSTA in step 320, and if it is "1", the starting state is determined to be the starting state in step 330, and the process at the time of starting described later is performed, and the process proceeds to step 350. On the other hand, when the CPU 4 determines that XSTA = 0 in step 320, the CPU 4 determines that the engine is not in the start-up state, executes normal processing in step 340, and proceeds to step 350.

The CPU 4 determines the starting state in steps 350 to 400. That is, when it is determined in step 350 that the engine has already started (XSTA = 1), the start determination time STT180 is 500 rp in step 360.
Set 180 ° CA time (60 ms) corresponding to m. On the other hand, when XSTA = 0 in step 350, the start determination time STT180 is set to 300r in step 370.
Set 180 ° CA time (100 ms) corresponding to pm. Next, in step 380, T180 obtained in step 300 is compared with the start determination time STT180. If T180 is small (high rotation),
In step 390, the starting state determination flag XSTA is set to "0".
If it is not smaller, XSTA = 1 is set in step 400, and the interrupt is exited.

FIG. 8 shows the starting process of step 330. The CPU 4 determines in step 331 the deceleration determination flag XS
It is determined whether or not GEN is "1", and when XSGEN = 0 (when deceleration is not performed), it is checked at step 332 whether or not the energization guard is necessary. That is, the actual energized scheduled time TON is compared with the minimum energized time TONG to determine the actual energized scheduled time T.
When ON is longer than the minimum energization time TONG, it is determined that the energization guard is unnecessary, and when the actual scheduled energization time TON is smaller than the minimum energization time TONG, it is determined that the energization guard is necessary. If the energization guard is not necessary, the CPU 4 causes the ignition signal IGt to fall in synchronization with the falling edge of the pulse signal N in step 334 to perform ignition (timing t2, t4, t6 in FIG. 2). Also, CPU
In step 4, if the energization guard is required in step 332, the energization guard process shown in FIG. 3 is performed in step 333. That is, if the energization time TON of the ignition coil when the energization ends at the trailing edge of the pulse is smaller than the minimum energization time TONG for securing the ignition energy, the energization continues after the trailing edge of the pulse. To secure the minimum energization time TONG.

On the other hand, when the deceleration determination flag XSGEN is "1" in step 331 (timing t8 in FIG. 2), the CPU 4 outputs the pulse signal N in step 335.
One-shot energization is performed from the falling edge of.
That is, the ignition signal IG is generated at the falling edge of the pulse signal N.
t is raised, and when the minimum energization time TONG has elapsed, the ignition signal IGt is lowered to energize only TONG (shown at t8 to t9 in FIG. 2).

On the other hand, when the primary current value It of the ignition coil 10 exceeds the overcurrent set value Ito due to an abnormal fuel supply of the engine or the like, the overcurrent cutoff circuit 7 forcibly turns off the power transistor 5 to turn off the ignition coil 10. Shut off the primary current.

The start condition determination flag XSTA and the deceleration determination flag XSGEN are set to "1" by initialization by turning on the ignition switch. In this way, by controlling the ignition signal IGt at the time of starting, ignition can be performed at the falling edge of the pulse signal N in the normal state (when not decelerating) in the starting state, and the overcurrent interruption circuit 7
By using, it is possible to properly control the energization time at the time of starting and prevent unnecessary heat generation of the power transistor. The minimum energization time T during deceleration of the internal combustion engine in the starting state
Only the ONG is energized, and as shown by the broken line in FIG. 2, the over-advanced angle due to the overcurrent cut operation of the overcurrent cutoff circuit 7 due to the prolonged energization time can be avoided, and good starting can be performed. ..

As described above, in this embodiment, when the primary current value It of the ignition coil 10 exceeds the overcurrent set value Ito by the overcurrent cutoff circuit 7, the power transistor 5 is forcibly turned off and the primary of the ignition coil 10 is forced. When the current is cut off, the CPU 4 (deceleration detection means, first control means, second control means) detects deceleration of the internal combustion engine in the starting state of the internal combustion engine, and during deceleration in the starting state of the internal combustion engine. Other than that, the power transistor 5 is turned on at a predetermined timing by the rotation angle sensor 8 to start energization, and the power transistor 5 is turned off at a reference crank angle near the top dead center (falling edge of pulse). When the internal combustion engine is decelerated while the engine is started, the rotation angle sensor 8 outputs power at the reference crank angle near the top dead center (falling edge of pulse). Turns on the transistor 5, and so as to turn off the power transistor 5 when the minimum energizing time corresponding to the power supply voltage VB of at least the ignition coil 10 TONG has elapsed. Therefore, when the overcurrent interruption device 7 is used, it is possible to prevent the over-advanced angle as shown by the broken line in FIG. 2 even during deceleration at the start of the internal combustion engine.

Further, the CPU 4 determines that the energization time TON of the ignition coil when the energization is terminated at the reference crank angle (the falling edge of the pulse) is shorter than the minimum energization time TONG for securing the ignition energy. Since the minimum energization time TONG is ensured by continuously energizing even after the reference crank angle (falling edge of the pulse) has elapsed, ignition is reliably performed.

The present invention is not limited to the above embodiment. For example, in the above embodiment, a pulse of the number of cylinders is used for the rotation angle sensor, but in addition, as shown in FIG. In the case of multiple pulses in which the angle signal is input for each time, similarly, the same angle (for example, TBDWL or T31) is compared before and after this ignition cycle, and TDC is used during deceleration.
One-shot energization from, and BT when not decelerating
It is also possible to energize after TDON (= T31−TON) from the DC 30 ° edge and ignite at the pulse rising edge at TDC. However, when the actual energization time is shorter than the minimum energization time TONG, the ignition timing is delayed so as to prevent the energization time from becoming TONG or less.

[0031]

As described in detail above, according to the present invention,
When the overcurrent cutoff circuit is used, an excellent effect of preventing an over-advance angle even during deceleration at the time of starting the internal combustion engine is exhibited.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an ignition device for an internal combustion engine of the present embodiment.

FIG. 2 is a timing chart for explaining various signal processes.

FIG. 3 is a timing chart for explaining signal processing.

FIG. 4 is a flowchart for explaining the operation.

FIG. 5 is a flowchart for explaining the operation.

FIG. 6 is a flowchart for explaining the operation.

FIG. 7 is a flowchart for explaining the operation.

FIG. 8 is a flowchart for explaining the operation.

FIG. 9 is a timing chart for explaining various signal processes in another example.

FIG. 10 is a timing chart for explaining a conventional technique.

[Explanation of symbols]

4 CPU as deceleration detection means, first control means, second control means 5 Power transistor 7 Overcurrent interruption circuit 8 Rotation angle sensor 10 Ignition coil

Claims (2)

[Claims] A rotation angle sensor for detecting a rotation angle of an internal combustion engine, a power transistor for controlling a primary current of an ignition coil, and a power transistor forcibly when the primary current value of the ignition coil exceeds an overcurrent set value. An overcurrent cutoff circuit for turning off the transistor to cut off the primary current of the ignition coil, deceleration detection means for detecting deceleration of the internal combustion engine in the starting state of the internal combustion engine, and deceleration in the starting state of the internal combustion engine by the deceleration detection means. At times other than time, the power transistor is turned on at a predetermined timing by the rotation angle sensor to start energization, and the power transistor is turned off at a reference crank angle near top dead center to end energization. During deceleration of the internal combustion engine by the control means and the deceleration detection means in the starting state, the power is applied at the reference crank angle near the top dead center by the rotation angle sensor. Turning the transistor, an ignition apparatus for an internal combustion engine characterized by comprising a second control means for turning off the power transistor when a current time corresponding to the power supply voltage of at least the ignition coil has elapsed. 2. The reference crank angle when the energization time of the ignition coil when the energization is terminated at the reference crank angle is shorter than the minimum energization time for securing the ignition energy. The ignition device for an internal combustion engine according to claim 1, wherein a minimum energization time is ensured by continuously energizing even after passing through.