JPH0531671B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention relates to an ignition device for an internal combustion engine, and more specifically, to comparing voltages from a rotation angle sensor and determining the time period during which current flows through the ignition coil according to on/off thresholds. The present invention relates to an ignition system for an internal combustion engine, comprising a first comparator circuit for controlling an internal combustion engine, and a second comparator circuit having a positive off-threshold value and activating a time signal generating circuit when that value is reached.

(b) Prior art Such an ignition device is described in, for example, German Patent Publication No. 3215728, in which the second
A time signal generation circuit operated by a comparator circuit performs a current cut-off during non-operation. That is, after expiration of a hold period provided by the time signal generator, the ignition coil current is cut off, thereby preventing overheating of the ignition coil and unnecessary power losses. This interruption of the ignition coil current is especially necessary when stopping the internal combustion engine, which is not driven, although the ignition system has been switched off, or when the engine speed is so low that the off-threshold of the first comparator circuit is not reached. .

In the conventional device, the circuit for cutting off the current is an analog circuit, which increases the cost, and since a capacitor is used in the time signal generating circuit, it is difficult to integrate the circuit.

(C) Purpose Therefore, the present invention has been made to solve these conventional drawbacks, and it is possible to integrate circuits in a simple manner without providing additional circuits, and is particularly suitable for digital An object of the present invention is to provide an ignition device for an internal combustion engine that can perform good ignition over various rotation speed ranges by operating the ignition device.

To this end, the present invention provides a comparator circuit controlled by the voltage of an inductive rotation angle sensor, whose positive on-threshold and associated negative off-threshold determine the average rotational speed. a first comparator circuit that controls the energization time of the ignition coil in the region via an ignition switching element; and a comparator circuit that has a positive on threshold and a positive off threshold and is controlled by the voltage of the rotation angle sensor. and a second comparison circuit that activates the time signal generation circuit when the voltage of the rotation angle sensor reaches its positive off threshold; When the voltage does not reach the off threshold of the first comparator circuit, the time signal generating circuit activates the ignition switching element when the standby time has elapsed;
Therefore, in an ignition system for an internal combustion engine in which the ignition coil current is cut off, the time signal generation circuit is configured as a counter that periodically counts the clock frequency when the second comparison circuit is turned off, The bistable switching circuit is switched to the first switching state when the count value reaches the upper count value that defines the lower limit of rotational speed, and when the off threshold of the first comparator circuit is not reached, the bistable switching circuit When the stable switching circuit is switched into the first switching state, the ignition switching element and thus the ignition coil current are interrupted, and if the off-threshold of the first comparator circuit is reached, the bistable switching circuit is first switched off. A count is started anew in the counter which holds the ignition switching element in the cut-off state when the second comparator circuit is next turned on while the bistable switching circuit is in the first switching state; An arrangement is adopted in which, when the counter reaches a second smaller count value while in the switching state, the ignition switching element, and therefore the ignition coil current, is activated with a delay by means of a logical coupling circuit.

(2) Examples Hereinafter, the present invention will be explained in detail according to examples shown in the drawings.

FIG. 1 shows an inductive rotation angle sensor 10 driven by the camshaft or crankshaft of an internal combustion engine.
The two terminals of this sensor are connected via two resistors 11, 12 to 13, 14 respectively to the respective inverting and non-inverting input terminals of operational amplifiers configured as comparison circuits 15, 16. The first comparison circuit 15 is fed back to the non-inverting input terminal via a series circuit of a resistor 17 and a Zener diode 18, while the second comparison circuit 16 is fed back to the non-inverting input terminal.
is also fed back via resistor 19. Power supply voltage terminal 20 is connected to ground via a voltage dividing circuit including resistors 21 and 22. The voltage dividing point between the two resistors 21 and 22 is connected to the connection point between the rotation angle sensor 10 and the resistors 14 and 12, and the inverting input terminal of the second comparison circuit 16 is connected to ground via the resistor 23. There is.

Both comparison circuits with electrically conductive rotation angle sensor 10 essentially correspond to the one described in DE-A-3215728. Further, the circuit described in the publication further describes configurations related to a safety circuit, a disturbance protection circuit, and a voltage stabilization circuit, but these are omitted here for the sake of simplicity.

The output of the first comparator circuit 15 is connected to the power supply terminal 20 via a resistor 24, and is also connected to a diode 2
5 to the base of transistor 26. The base and collector of transistor 26 are connected to power supply terminal 20 via resistors 27 and 28, respectively. Also, its emitter is transistor 29
is connected to ground through the base emitter circuit. The collector of transistor 29 is connected to power supply terminal 20 via resistor 30 and also to the base of output transistor 31 . The emitter of the output transistor 31, preferably configured with a Darlington connection, is connected to ground and its collector is connected to the ignition coil arrangement 32. This ignition coil arrangement 32 supplies a high-voltage ignition signal to the spark plug in a well-known manner. The output of the second comparator circuit 16 is connected to the power supply terminal 20 via a resistor 33, to the clock input terminal T of a D flip-flop 35 via an inverter 34, and further to an exclusive OR gate (EXOR) 36 and a D flip-flop 37. Connected to clock input terminal T. Ixkuru-Shivor Gate 3
The output of 6 turns the clock frequency generator 38 on and off, and the counter 39 is reset via the reset input terminal R. Clock frequency generator 38 and counter 39 function as a time signal generating circuit. The clock frequency of clock frequency generator 38 can be controlled by power supply voltage Ub. Further, the frequency of the clock frequency generating circuit 38 is inputted to the clock input terminal T of the counter 39. This counter has four output terminals, each of which generates a signal when a predetermined value B1 to B4 is reached. The output terminal related to the count value B3 is the reset input terminal R of the flip-flop 37.
The output Q of this flip-flop is connected to the D input terminal of the flip-flop 35.
The output terminal of the counter 39 associated with the count value B4 is connected to the clock input T of the D flip-flop 40, and the output Q of the flip-flop 40 is connected to the other input terminal of the exclusive OR gate 36 and to the input terminal of the AND gate 41. At the same time, it is connected to the base of the transistor 29 via a resistor 42.

On the other hand, the output of counter 39 associated with count value B1 is connected to the other input terminal of AND gate 41, and the output of this gate is connected to the reset input terminal of flip-flop 40. Further, the output of the counter 39 associated with B2 is connected via an AND gate 43 to the clock input terminal T of a D flip-flop 44, and the inverted output of this flip-flop is connected via a diode 45 to the transistor 26.
connected to the base of Furthermore, the output Q of flip-flop 35 is connected to the other input terminal of AND gate 43. The output of the first comparison circuit 15 is connected to the reset input terminal R of the flip-flop 44 via an inverter 46. Furthermore, a power supply voltage is supplied to the D input terminals of flip-flops 37, 40, and 44 through power supply terminal 20, respectively.

Figure 2 shows the output voltage from the rotation angle sensor 10.
Ug is illustrated. Since both comparison circuits 15 and 16 have the same on-threshold value Ue ₁ to Ue ₂ ,
Both comparison circuits work together. That is, the output signal changes from a "1" signal to a "0" signal. The second comparator circuit 16 has a positive off-threshold, thus a faster-reaching off-threshold Ua ₂ , while the comparator circuit 15 has a negative off-threshold, thus a slower off-threshold Ua. Has ₁ . When both comparison circuits are turned off, the output signal correspondingly changes from "0" to "1" signal. The ON and OFF thresholds differ depending on the input circuits of the feedback circuits 17, 18 to 19 and the comparison circuits 15, 16. Under normal conditions, that is, when the rotation speed is the average rotation speed, the closing time Ts, that is, the period during which current flows through the primary winding of the ignition coil, is the comparator circuit 1.
5. The ignition point is determined when the off-threshold Ua ₁ is reached, ie when the closing time Ts ends. If at time _t1 the second comparator circuit 16 reaches its off-threshold value _Ua2 , the time processing circuit formed by the clock frequency generator 18 and the counter 39 is activated.

At the end of the hold time defined by this time processing circuit at time t ₂ , the current flowing through the primary is interrupted (usually this has already taken place), so that the current is interrupted during non-operation. If the rotation speed is very small, i.e. the signal level is very small, the threshold Ua ₁
Emergency ignition is performed when the ignition temperature is not reached.

Next, refer to the signal waveform diagram shown in Figure 3.
We will explain two cases. First, it is assumed that the internal combustion engine has an average rotational speed, for example, 2000 to 3000 rpm. As already explained in connection with FIG. 2, the output signals U15, U15,
U16 is output. When the comparison circuit 16 is off,
That is, when the output changes from a "0" signal to a "1" signal, a "1" signal is generated at the output of the exclusive OR gate 36 during this "1" signal (other than the exclusive OR gate). A ``0'' signal is applied to the input terminal of . This causes the clock frequency generator 38 to operate, and the clock signal U38 is counted by the counter 39 (Z39). The next edge of signal U16 resets counter 39 again. The average rotational speed can be defined as the rotational speed at which the counting state is between count values B3 and B4. Since the count value B4 is not reached, flip-flop 40 remains reset and takes no action. As will be explained in detail later, in this rotation speed range, the output of the flip-flop 35 is also at the 0 level, so the flip-flop 44 also has no effect. In this rotational speed range, the time during which current flows through the ignition coil 32, ie the closing time, is therefore determined solely by the comparison circuit 15 and its output signal U15.

Next, a case in the low rotational speed region will be explained.
When the rotational speed is below 2000 rpm or 1500 rpm, it is considered to be a low frequency circuit.
This limit rotation speed is determined by count value B4.
In FIG. 3, the signal waveforms of low rotational speeds are shown as the fifth to tenth signals. Since the rotation speed is in the low range, the counter 39 is the counted value.
B4, thereby producing a "1" signal at its output, which causes flip-flop 40
is set. The counter 39 is reset by the output signal U40 of the flip-flop 40 via the exclusive OR gate 36. When the output signal of the comparator circuit 16 changes to a 0 signal, the counter 39 starts counting again because a signal of "1" is applied to the input of the exclusive OR gate 36 via the output of the flip-flop 40. When the count reaches B1, flip-flop 40 is reset via AND gate 41, which turns off transistor 29 and allows current to flow through transistor 31.
The counter 39 is reset again via the exclusive OR gate 36 and starts counting anew from the next rising edge of the signal U16. In this way, the time Tv is obtained from the count value B1, and the start of current flowing to the ignition coil is delayed by that amount.

In this way, the cam angle is reduced at reduced rotational speeds, and power loss in this region can be effectively reduced. In FIG. 4, the variation of this cam angle at 1500 revolutions per minute is illustrated by a solid line. What is shown by the dotted line is the characteristic when this cam angle does not decrease. FIG. 4 shows the duty ratio STV of the signal of the output transistor 31 with respect to the rotational speed.

The reaching of the count value B4 simultaneously means the end (T ₂ ) of the waiting time obtained by the time signal generator starting at time t ₁ and constituted by circuits 38, 39. Due to the reason stated at the beginning, the signal from the comparator circuit 15 is at the off threshold value Ua ₁
If the comparator circuit is not turned off for other reasons, current will continue to flow through the ignition coil 32 without producing an ignition spark. However, at time _t2 , flip-flop 40 is set and a ``1'' signal is formed at the base of transistor 29, thereby cutting off transistor 31 and cutting off the current flowing through the coil. This results in a non-operating current interruption when the internal combustion engine is stopped, while an auxiliary ignition spark is produced at low engine speeds. Off threshold Ua ₂
Since is positive, the time signal generating circuits 38 and 39 are reliably operated when the internal combustion engine is stopped in any case.

When the rotational speed is in the average value or in the low range region, the count value of the counter 39 will be larger than B3, so that the flip-flop 37, which is set by the rising edge of the signal U16, will change the count value.
When it reaches B3, it is reset by the counter 39. The output of flip-flop 37 has a signal example U37.
is obtained. Since the flip-flop 35 receives the output signal of the flip-flop 37 at the end of the signal U16 by the inverter 34 (always zero at this point), the output signal of the flip-flop 35 is zero. Therefore, and gate 4
3 is in a blocked state. The flip-flop 44 therefore has no effect in the reduction and average speed ranges.

Next, the case of a high rotation speed, for example, 3000 rotations/minute or more will be explained. This example is shown in Figure 3.
The signals are shown as the 15th to 15th signal strings. Since the count value does not reach B3 at high rotation speeds,
Flip-flop 37 is no longer reset.
Therefore, a signal of "1" is always obtained on the output side, so that a signal of "1" always appears in the flip-flop 35. Therefore, the AND gate 43 receives the output B2 from the counter 39. is open. When the count reaches B2, flip-flop 44 is set (a zero signal appears at the inverted output) and reset by the rising edge of signal example U15 (a "1" signal appears at the inverted output). The signal sequence appearing at the output of the flip-flop 44 obtained in this way
U44 acts on the base of transistor 26, and as long as a zero signal appears at the output of flip-flop 44, transistor 26 is turned off regardless of what signal appears at the output signal of comparator circuit 15. When transistor 26 is turned off, current flows through ignition coil 32. If the flip-flop 44 is not provided, the current starts to flow for the first time at time _t3 , so if the flip-flop 44 is provided, the cam angle Tg increases at high rotational speeds. FIG. 4 shows that at 3500 revolutions per minute, the cam angle increases as the curve shown by the solid line changes.

Instead of increasing the cam angle only once in the high rotational speed region, it is also possible to increase the cam angle several times at different rotational speeds. This is illustrated in dotted lines in FIG. When using the same counter 39, other output terminals B5 and B6 are provided in place of the output terminals B2 and B3 for each cam angle variation, and the circuits 34, 35, 37, and 4 are connected via them.
The circuit corresponding to No. 3 is driven. When a plurality of AND gates 43 are provided in multiple stages as described above, the output thereof must be input to the clock input of the flip-flop 44 via a circuit. In this way, it is possible to increase the cam angle finely and stepwise in a high rotation range using a small number of circuits and an inexpensive circuit.

Here, one counter 39 is provided in the time signal generation circuit.
The provision of the It can be seen that an increase in the cam angle can be achieved. For this purpose, it is only necessary to provide a relatively simple and inexpensive circuit for the counter 39.

The characteristics shown by the dashed line in FIG. 4 show the characteristics when the power supply voltage becomes large (for example, when the battery charge value is large). The curve can be shifted by controlling the clock frequency of the clock frequency generator 38 according to the supply voltage Ub. Thereby, it is possible to reach the values of the count values B1 to B4 at different times, and it is possible to functionally match the range in which the characteristics vary not only with respect to the rotation speed but also with respect to the power supply voltage. Furthermore, current interruption during non-operation can be performed functionally correctly. That is, when the power supply voltage increases, it can be performed faster.

For example, the circuit element 74 for the counter 39
C161 and for the flip-flop, for example, circuit element 4013 (eg, Motorola, National) can be used.

As explained above, in the embodiments of the present invention, processing is performed digitally, which simplifies processing, allows for circuit integration, and further enables implementation by a microcomputer. In particular, the cam angle can be reduced in the reduced speed range using a time signal generator configured as a digital counter, with the advantage that no additional circuitry is required.

Furthermore, in the embodiment of the present invention, the time signal generation circuit or the rotation speed information obtained by the time signal generation circuit is used to increase the cam angle in the high rotation speed region, thereby requiring an even more expensive circuit. This means that the counter used as the time signal generation circuit is used three times as much. Furthermore, in the present invention, the clock frequency input to the counter can be controlled in relation to the power supply voltage, thereby functionally matching the cam angle not only with the rotational speed but also with the power supply voltage, so that the clock frequency input to the counter can be controlled in relation to the power supply voltage. It is possible to reduce power loss in the region, and it is also possible to obtain a sufficient cam angle in the high rotation speed region.

(e) Effects As described above, the present invention includes a counter that is activated when the voltage of the rotation angle sensor reaches the positive off threshold of the second comparison circuit.
During non-operation, when the engine is stopped and the rotational speed is 0, the counter reaches the predetermined count value and the voltage of the rotation angle sensor does not reach the off threshold of the first comparison circuit, so the bistable By switching the switching circuit into the first switching state, the ignition switching element and thus the ignition coil current are cut off, and the ignition coil current is cut off during non-operation. In this manner, the ignition coil current is reliably cut off during non-operation when the internal combustion engine is stopped, thereby preventing the ignition coil from overheating and unnecessary power consumption.

On the other hand, at such low rotational speeds that the counter reaches the above-mentioned count value and the voltage of the rotation angle sensor reaches the off threshold of the first comparator circuit, the count that keeps the ignition switching element in the cut-off state is changed again in the counter. The ignition coil current is applied with a corresponding delay, reducing the energization time of the ignition coil. Therefore, even when the rotational speed is in the low rotational speed range, auxiliary ignition can be performed and the energization time of the ignition coil in the low rotational speed range can be reduced.

Thus, in the present invention, by providing a counter that is activated when the voltage of the rotation angle sensor reaches the positive off threshold of the second comparator circuit, the ignition coil current can be interrupted when the internal combustion engine is not operating. In addition, it is possible to realize the auxiliary ignition in the reduced rotational speed region and to reduce the energization time of the ignition coil.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the schematic configuration of the ignition device according to the present invention, Fig. 2 is a characteristic diagram showing the characteristics of the signal obtained from the rotation angle sensor, and Fig. 3 is the
FIG. 4 is a signal waveform diagram for explaining the operation of the circuit shown in the figure, and FIG. 4 is a characteristic diagram showing the characteristics of the cam angle. 10... Rotation angle sensor, 15, 16... Comparison circuit, 31... Output transistor, 32... Ignition coil, 38... Clock frequency generator, 39...
counter.

Claims (1)

Claims: 1. A comparator circuit controlled by the voltage of an inductive rotation angle sensor 10 which, by virtue of its positive on-threshold and associated negative off-threshold, controls the ignition coil in the average speed range. a first comparator circuit 15 that controls the energization time of 32 via the ignition switching element 31; and a comparator circuit that has a positive on threshold and a positive off threshold and is controlled by the voltage of the rotation angle sensor. When the voltage of the rotation angle sensor reaches its positive off threshold, the time signal generation circuit 39
and a second comparison circuit 16 that operates the time signal generating circuit when the rotational speed of the internal combustion engine is below the lower limit value and the voltage of the rotation angle sensor does not reach the off threshold of the first comparison circuit 15. In an ignition system for an internal combustion engine in which the ignition switching element 31 and therefore the ignition coil current are cut off when the standby time has elapsed, the time signal generation circuit 39 is periodically activated by turning off the second comparison circuit 16. The bistable switching circuit 40 is configured as a counter that counts the clock frequency at the same time, and when the counted value reaches the upper counted value (B4) that determines the lower limit of the rotational speed, the bistable switching circuit 40 is switched to the first switching state. If the off-threshold of the first comparator circuit 15 is not reached, the bistable switching circuit 40 is switched into the first switching state so that the ignition switching element 31 and thus the ignition coil current is interrupted and the first If the off threshold of the comparator circuit 15 is reached, first while the bistable switching circuit 40 is in the first switching state, the second comparator circuit 16 is next turned on and the ignition switching element 31 is switched on. The counting is started anew in the counter 39 to keep the switch in the cut-off state, and if the counter 39 then reaches a second smaller count value (B1) while the bistable switching circuit 40 is in the first switching state, the logical combination An ignition system for an internal combustion engine, characterized in that the ignition switching element 31 and thus the ignition coil current are activated with a delay (Tv) by means of a circuit 41. 2. Ignition device for an internal combustion engine according to claim 1, characterized in that the delayed activation of the ignition switching element 31 is carried out by switching the bistable switching circuit 40 to a second switching state. . 3. The clock frequency is activated and the counter 39 is reset only when the bistable switching circuit 40 enters the first switching state via the gate circuit 36 or when the second comparator circuit 16 enters the off state. An ignition device for an internal combustion engine according to claim 1 or 2. 4. If the counter 39 does not reach the count value (B3) corresponding to the high rotation speed, in order to increase the cam angle, when the counter 39 reaches another small predetermined count value (B2), another bistable The internal combustion engine according to any one of claims 1 to 3, characterized in that the switching circuit 44 is activated and the activated bistable switching circuit 44 causes current to flow through the ignition coil. Engine ignition system. 5. In order to activate the other bistable switching circuit 44, a bistable switching device 34, 35, 37 is provided which is switched into a first switching state by the second comparison circuit 16, the second switching state of which is switched to the counter. 5. The ignition system for an internal combustion engine according to claim 4, wherein the ignition system is obtained when B39 does not reach the count value (B3) corresponding to a high rotational speed. 6. The bistable switching device comprises third and fourth bistable switching circuits 37, 35 set by different signal ends of the second comparator circuit 16.
A third bistable switching circuit 3
7 is reset when the counter 39 reaches the count value (B3) corresponding to the high frequency rotation speed, and when the set signal appears, the output signal of the third bistable switching circuit 37 is switched to the fourth bistable switching circuit. The ignition device for an internal combustion engine according to claim 5, wherein the ignition device is sent to the circuit 35. 7 The other bistable switching circuit 44 is the first
5. The ignition system for an internal combustion engine according to claim 4, wherein the ignition system is reset by an off signal from the comparison circuit 15. 8. In order to control the energization time, the output of the bistable switching circuit 40 as well as the other bistable switching circuit 44 is connected to the output transistor 31 of the ignition switching element which controls the ignition coil current.
Drive transistors 29 and 26 connected to the front stage of
The ignition device for an internal combustion engine according to any one of claims 4 to 7, characterized in that the ignition device is connected to a base of the invention. 9. Claim 1, characterized in that the clock frequency can be adjusted according to the power supply voltage (Ub).
The ignition device for an internal combustion engine according to any one of Items 1 to 8.