JPS6324147B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for controlling the ignition timing of an engine by electronic means.

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a first angle sensor that outputs an angle pulse signal CP every time the engine crankshaft rotates once, and 2 is a reference pulse signal RP that outputs a reference pulse signal RP at a predetermined crank angle before the top dead center of the engine. 3 is an arithmetic circuit that inputs the reference pulse signal RP output from the second angle sensor 2 and outputs ignition timing data SPK and ignition coil non-energized angle data DWL; 4 is an OR
A reset circuit is connected to one end of the circuit 7 and sends out a reset signal RST when the power is turned on. 5 is a counter circuit with a built-in subtraction counter that can be preset, and a data input for inputting the ignition timing data SPK output from the arithmetic circuit 3. a terminal 5a, a preset terminal 5b for inputting the reference pulse signal RP as a preset signal output from the second angle sensor, and a clock terminal for inputting the angle pulse signal CP output from the first angle sensor 1. 5c and the ignition pulse signal SP to the reset terminal 8 of the flip-flop circuit 8 via the OR circuit 7.
and an output terminal 5d that outputs to a. Reference numeral 6 denotes a counter circuit incorporating a subtraction counter that can be preset, and includes a data input terminal 6a for inputting the ignition coil de-energized angle data DWL output from the arithmetic circuit 3, and a data input terminal 6a for inputting the ignition coil de-energized angle data DWL output from the arithmetic circuit 3, and a preset signal output from the counter circuit 5. A preset terminal 6b to which the ignition pulse signal SP is input, a clock terminal 6c to which the angle pulse signal CP output from the second angle sensor 2 is input, and an energizing pulse signal DP to the set terminal 8b of the flip-flop circuit 8. and an output terminal 6d. 9 is a register,
10 is a power transistor, which inputs the output signal from the output terminal 8c of the flip-flop circuit 8 to its base via the register 9; if the input signal is zero, that is, "0", it turns OFF; if it is "1", it turns OFF. It is configured to turn on. 11 is an ignition coil, one end of which is connected to the collector of the power transistor 10;
The structure is such that the power is turned on and off by turning on and off, and ignition occurs in this cutoff state.

Based on the above configuration, the operation of the conventional example will be explained.

The calculation circuit 3 calculates the optimum ignition timing SPK according to operating parameters such as engine speed and manifold negative pressure, and calculates the ignition timing data SPK.
is sent to the data input terminal 5a of the counter circuit 5. Further, the arithmetic circuit 3 calculates the ignition coil non-energization angle so as to obtain the optimum ignition coil energization time according to operating parameters such as engine speed and power supply voltage, and calculates the ignition coil non-energization angle data.
DWL is sent to the data input terminal 6a of the counter circuit 6. When the counter circuit 5 presets the ignition timing data SPK applied to the data input terminal 5a at the time when the reference pulse signal RP outputted from the second angle sensor 2 is inputted to the preset terminal 5b into a built-in subtraction counter. At the same time, subtraction counting is started by the angle pulse signal CP applied to the clock terminal 5c, and when the counter value reaches "0", the ignition pulse signal SP is outputted from the output terminal 5d. The ignition pulse signal SP is OR
Since the voltage is applied to the reset terminal 8a of the flip-flop circuit 8 through the circuit 7, the output terminal 8c of the flip-flop circuit 8 becomes "0", and the power transistor 10 is turned off through the register 9. As a result, the ignition coil 11 changes from the energized state to the energized state, and ignition occurs.

On the other hand, the counter circuit 6 receives the ignition pulse signal.
When SP is input to the preset terminal 6b, that is, when the current is cut off, the ignition coil de-energized angle data DWL applied to the data input terminal 6a is preset to the built-in subtraction counter, and at the same time, the ignition coil de-energized angle data DWL applied to the data input terminal 6a is preset. Subtraction counting is started by the angle pulse signal CP, and when the counter value reaches "0", the energization pulse signal DP is output from the output terminal 6d. The energizing pulse signal DP
occurs, the flip-flop circuit 8
The output terminal 8c becomes "1", and the power transistor 10 is turned on via the resistor 9. As a result, energization of the ignition coil 11 is started.

Furthermore, when the power is turned on, a reset signal RST is sent out from the reset circuit 4. The reset signal
Since RST is applied to the reset terminal 8a of the flip-flop circuit 8 through the OR circuit 7, the output terminal 8c of the flip-flop circuit 8 becomes "0" and the ignition coil 11 is initialized to a non-energized state.

Since the conventional ignition timing control device is configured as described above, if the angle pulse signal CP and the reference pulse signal RP are input normally, ignition can be performed at the ignition timing calculated by the calculation circuit 3. ,
In addition, an optimum energization time can be obtained. However, if the angle pulse signal CP is no longer input due to a failure or disconnection of the first angle sensor 1 while the ignition coil 11 is in the energized state, the counter circuit 5 stops counting.
The ignition pulse signal SP is not output from the output terminal 5d of the ignition coil 11, and the ignition coil 11 maintains the energized state. As a result, the current flowing through the ignition coil 11 increases to a value determined by the resistance value of the ignition coil 11, and the ignition coil 11 and the power transistor 1
Since the current value far exceeds the allowable current value of 0, there is a disadvantage that there is a risk of causing destruction of the ignition coil 11 and the power transistor 10. Furthermore, some conventional devices have a current control circuit added to the power transistor 10 to limit the current flowing to a constant value, but in this case, the voltage V _CE between the collector and emitter of the power transistor 10 increases. There was a drawback that the power loss of the power transistor 10 exceeded the allowable value, resulting in destruction of the power transistor 10.

This invention was made to eliminate the drawbacks of the conventional ones as described above. When the engine is rotating but the angle pulse signal is no longer input, this invention is detected and the ignition coil is energized. The object is to provide an ignition timing control device that forcibly shuts off and protects the power transistor and ignition coil.

An embodiment of the present invention will be shown below along with FIGS. 2 to 4.

FIG. 2 shows an embodiment of the present invention, in which the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and detailed explanation thereof will be omitted.

In FIG. 2, reference numeral 12 denotes a flip-flop circuit, which has a reset terminal 12a that inputs the angle pulse signal CP output from the first angle sensor 1, and a reference pulse signal output from the second angle sensor 2.
A set terminal 12b that inputs RP, and an output terminal 12c that outputs a signal that becomes "1" when the reference pulse signal RP is input to the set terminal 12b.
Equipped with. 13 is the flip-flop circuit 1
Input the output signal from 2 to generate the reference pulse signal RP.
A delay circuit 14 delays the input signal by a time Ta corresponding to the pulse width of and outputs the signal; 14 has one end of the input connected to the delay circuit 13, the other end of the input connected to the second angle sensor, and an output terminal connected to the OR This is an AND circuit connected to circuit 7.

Next, the operation will be explained with reference to FIGS. 3 and 4.

First, the operation when the angle pulse signal CP is normally inputted will be explained with reference to FIG.

Set terminal 12b of flip-flop circuit 12
When the reference pulse signal RP as shown in FIG. 3a is input to the flip-flop circuit, the output terminal 12 of the flip-flop circuit
c becomes "1" and a waveform as shown in FIG. 3c is obtained. After a time Ta after this output terminal 12c becomes "1", the output terminal 13a of the delay circuit 13 becomes "1" as shown in FIG. 3d. At this point,
Since the reference pulse signal RP is already "0", the two input terminals of the AND circuit 14 will not become "1" at the same time, and the output terminal 14a of the AND circuit 4 will be as shown in FIG. It holds "0" as shown. Further, since the reset terminal 12a of the flip-flop circuit 12 is connected to the first angle sensor 1 which outputs the angle pulse signal CP as shown in FIG. 3b, it is set to "1" by the reference pulse signal RP.
The output terminal 12c becomes "0" in response to the first angle pulse signal CP after the reference pulse signal is generated. Time after the output terminal 12c becomes “0”
After Ta, the output terminal 13a of the delay circuit 13 is also “0”
becomes. It is clear that in this case as well, the output terminal 14a of the AND circuit 14 remains at "0". When the angle pulse signal CP is input normally, the above operation is repeated, so the output terminal 14a of the AND circuit 14 is always "0". Therefore, since the operation when the angle pulse signal CP is normally input does not affect the operation of the flip-flop circuit 8, it is exactly the same as the conventional ignition timing control device shown in FIG. 1 above. .

Next, the operation when the angle pulse signal CP is no longer input will be explained with reference to FIG.

The reference pulse signal RP is periodically applied to the set terminal 1 of the flip-flop circuit 12 as shown in FIG.
2a, but unless the angle pulse signal CP is input as shown in FIG. 4b, the flip-flop circuit 12 will not be reset as shown in FIG. 4c. As a result, after the reference pulse signal RP is input, the engine rotates due to inertia without any angle pulse signal CP being input, and when the next reference pulse signal RP is input, the output terminal 13a of the delay circuit 13 becomes , remains at "1" as shown in FIG. 4d, so that the output terminal 14a of the AND circuit 14 outputs a pulse signal as shown in FIG. 4e. This pulse signal passes through the OR circuit 7 and is sent to the reset terminal 8a of the flip-flop circuit 8.
is applied to the flip-flop circuit 8.
The output terminal 8c becomes "0", and the power transistor 10 is turned off via the register 9. As a result, the ignition coil 11 changes from the energized state to the energized state, and ignition occurs.

Further, in the above embodiment, the angle pulse signal CP is connected to the reset terminal 12a of the flip-flop circuit 12.
However, as another embodiment of the present invention, by utilizing the fact that when the angle pulse signal CP is no longer input, the ignition pulse signal SP is no longer output, as shown in FIG. It is clear that the same effect can be obtained by applying the ignition pulse signal SP to the reset terminal 12a of the flip-flop circuit 12 instead of the angle pulse signal CP.

It goes without saying that the above two embodiments shown in FIGS. 2 and 5 can be easily constructed using a device having arithmetic capabilities such as a microcomputer and peripheral elements having a timer function.

As described above, according to the present invention, when the angle pulse signal is no longer input, this state is detected and the energization of the ignition coil is forcibly cut off, so all that is required is an energization cutoff means. Although this is a simple configuration, the engine is rotating when the ignition coil is energized, but even if the angle pulse signal is not input due to a failure or disconnection of the first angle sensor, the ignition coil continues to be energized. As a result, the power transistor and the ignition coil can be prevented from being destroyed, which is a great effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional ignition timing control device, FIG. 2 is a block diagram showing an embodiment of the present invention, FIGS. 3 and 4 are waveform diagrams showing the operation of each part in FIG. FIG. 5 is a block diagram showing another embodiment of the present invention. 1, 2...Angle sensor, 3...Arithmetic circuit, 4...
...Reset circuit, 5, 6... Counter circuit, 8,
12...Flip-flop circuit, 10...Power transistor, 11...Ignition coil, 13...Delay circuit.

Claims (1)

[Scope of Claims] 1. A first angle sensor that generates an angle pulse signal every time the engine rotates by a predetermined angle, and a first angle sensor that generates a number of reference pulse signals corresponding to the number of cylinders during one rotation of the engine. An angle sensor No. 2, an arithmetic circuit that calculates the ignition timing and energization start timing of the ignition coil according to the operating state of the engine, and an arithmetic circuit that inputs and counts the angle pulse signal, and calculates the energization based on the counted value. energization control means that generates an energization signal for starting energization of the ignition coil at a start time; and energization control means that counts the angle pulse signal from the time point when the reference pulse signal is input, and the counted value is calculated by the arithmetic circuit. ignition control means for generating an ignition signal for cutting off current to the ignition coil when the ignition timing coincides with the ignition timing; An ignition timing control device comprising: energization cutoff means for cutting off energization to a coil. 2. The energization cutoff means determines that the angle pulse signal is no longer being input when the next reference pulse signal is input without any angle pulse signal being input after the reference pulse signal is input. An ignition timing control device according to claim 1. 3. The current cutoff means determines that the angle pulse signal is no longer input when the next reference pulse signal is input without the ignition signal being input after the reference pulse signal is input. The ignition timing control device according to scope 1.