JPS58214672A - Ignition timing controller - Google Patents

Abstract

PURPOSE:To protect a power transistor and an ignition coil, by forcibly cutting off conduction of an electric current to the ignition coil when an angle pulse signal is not output during rotation of an engine. CONSTITUTION:A flip flop circuit 12 is provided with a reset terminal 12a, to which an angle pulse signal CP output from the first angle sensor 1 is input, a set terminal 12b, to which a reference pulse signal RP output from the second angle sensor 2 is input, and an output terminal 12c. An output signal from the circuit 12 is input to a delay circuit 13, and the circuit 13 delays the input signal by the time Ta corresponding to a pulse width of the reference pulse RP. An ''and'' of the circuit 13 and the sensor 2 is obtained by an AND circuit 14. In this way, when the angle pulse signal is not input, conduction of an electric current is inhibited to an ignition coil, consequently a power transistor and the ignition coil can be prevented from damage.

Description

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

Conventionally, as a device of this type, the one shown in Fig. 1 is an fc
. 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 engine/top dead center. 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 circuit; Connected to one end of 7 and outputs a reset signal R8T 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 terminal 5a that inputs the ignition timing data SPK output from the arithmetic circuit 3, and an output from the second angle sensor. A preset terminal 5b inputs a reference pulse signal RP as a preset signal, a clock terminal 5c inputs an angle pulse signal CP output from the first angle sensor l, and an ignition pulse signal SP is inputted to the OR circuit 7. and an output terminal 5d that outputs to the reset terminal 8a of the flip-flop circuit 8 via. Reference numeral 6 denotes a counter circuit incorporating a presettable subtraction counter, which 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 counter circuit 5 as a preset signal. A preset terminal 6b for inputting the ignition pulse signal SP, and a clock terminal 6 for inputting the angle pulse signal CP output from the second angle sensor 2.
c, and an output terminal 6d for outputting the energization noggle signal DP to the set terminal 8b of the flip-flop circuit 8. 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;
, f.

If so, it is OF F L, and if it is "1", it is turned ON. Reference numeral 11 denotes an ignition coil, one end of which is connected to the collector of the power transistor 10, which conducts energization/cutoff operations when the power transistor 10 is turned on and off, and is configured so that ignition occurs in this cutoff state. .

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

Arithmetic circuit 3 determines the optimum ignition timing SPK according to operating parameters such as engine speed and manifold negative pressure.
is calculated, and 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-energizing angle so as to obtain the optimum ignition coil energizing time according to operating parameters such as engine speed and power supply voltage, and outputs the ignition coil non-energizing angle data DWL to the data input terminal of the counter circuit 6. 6a. The counter circuit 5 sends the reference)4 pulse signal RP output from the second angle sensor 2 to a preset terminal 5b.
At the same time, the ignition timing data SPK applied to the data input terminal 5a is preset to a built-in subtraction counter, and at the same time, subtraction counting is started by the angle pulse signal CP applied to the clock terminal 5c. 0'', the ignition signal SP is output from the output terminal 5d. The ignition pulse signal 5 is connected to the reset terminal 8a of the flip-flop circuit 8 through the PUOR circuit 7.
Therefore, the output terminal 8c of the flip-flop circuit 8 becomes "O", and the power transistor 10 is turned off through the resistor 9. As a result, ignition coil 1
No. 1 changes from the energized state to the cut-off state, and ignition occurs. .

On the other hand, the counter circuit 6 presets the ignition coil de-energization angle data DWL applied to the data input terminal 6a into a built-in subtraction counter at the time when the ignition pulse signal SP is input to the preset terminal 6b, that is, at the time of de-energization. At the same time, subtraction counting is started based on the angle noggle signal CP applied to the clock terminal 6c, and when the counter value reaches 0'', the energization pulse signal DP is output from the output terminal 6d.The energization pulse At the time when the signal DP is generated, the output terminal 8c of the flip-flop circuit 8 becomes .degree.1", and the arm transistor 1.degree. is turned on via the register 9. As a result, the ignition coil 11
energization starts.

Furthermore, when the power is turned on, the reset circuit 4 sends out a reset signal R8T. The reset signal R8T is sent to the reset terminal 8 of the flip-flop circuit 8 through the OR circuit 7.
'a, 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, it is possible to ignite at the ignition timing calculated by the calculation circuit 3 while the engine is rotating, and to obtain the optimum energization time. can. However, if the engine stops while the ignition coil 11 is in the energized state, the angle pulse number CP will no longer be output from the first angle sensor l.
The counter circuit 50 subtraction count also stops, so as long as the engine is stopped, the output terminal 5 of the counter circuit 5
The ignition pulse signal SP is not output from d, and the ignition coil 1
1 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, which far exceeds the allowable current value of the ignition coil 11 and the i4 power transistor 10. There is a drawback that there is a risk that the power transistor 10 may be destroyed. 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 collector-emitter voltage Vc of the power transistor 10 increases. Therefore, the power loss of the power transistor 10 exceeds the allowable value, which also leads to the destruction of the mother power transistor 10.

This invention was made to eliminate the drawbacks of the conventional ones as described above, and when the engine is rotating but the angle pulse signal is no longer input, this invention is detected and the ignition coil is forced to be energized. The object of the present invention is to provide an ignition timing control device that protects the power transistor and the 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 equivalent parts,
I will omit the detailed explanation.

In FIG. 2, 12 is a flip-flop circuit;
a reset terminal 12a that receives the angle reference pulse signal CP output from the second angle sensor 1; a set terminal 12b that receives the reference pulse signal RP output from the second angle sensor 2; and a set terminal 12b that receives the reference pulse signal RP output from the second angle sensor 2. is the set terminal 1
2b, the output terminal 12c outputs a signal that becomes "■" when inputted to the flip-flop circuit 12, and 6 13 is a time period corresponding to the pulse width of the reference pulse signal RP when the output from the flip-flop circuit 12 is inputted. a delay circuit 14 which delays the input signal by 1 and outputs the input signal, and 14 is an AND circuit whose one end of the input is connected to the delay circuit 13, the other end of the input is connected to the second angle sensor, and the output terminal is connected to the OR circuit 7. It is a circuit.

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

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

When the reference pulse signal RP as shown in FIG. 3a is input to the set terminal 12b of the flip-flop circuit 12 and the angle nogle signal CP as shown in FIG. 3 is input to the reset terminal 12a, the flip-flop circuit Output terminal 12C of
becomes "l" and obtains a waveform as shown in FIG. 3C. After a time Ta after the output terminal 12c becomes "1", the output terminal 13a of the delay circuit 13 becomes "1" as shown in FIG. 3d.
°.

At this point, the reference pulse signal RP is already at "O", so the two input terminals of the AND circuit 14 do not become "L" at the same time, and the output terminal 14a of the AND circuit 14 is at the third As shown in Figure e, the reset terminal 121L of the flip-flop circuit 12 is held at "0".
Since the output terminal 12c is connected to the first angle sensor 1, the output terminal 12c which is set to "1" by the reference pulse signal RP becomes "0" by the first angle pulse signal CP after the reference pulse signal is generated. After a time Ta after 12c becomes "0", the output terminal 13a of the delay circuit 13 also becomes "0".
becomes. In this case as well, the output terminal 14a of the AND circuit 14
It is clear that the angle pulse signal C remains at °0''.
When P is input normally, the above operation is repeated, so the output terminal 14a of the AND circuit 14 is always 0''. Therefore, when the angle pulse signal CP is input normally, the operation is as follows. Since it 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 described 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 input to the set terminal 12a of the flip-flop circuit 12 as shown in FIG. 4a, but if the angle pulse signal CP is not input as shown in FIG. The pull circuit 12 is shown in FIG.
As shown in the figure, it is not reset. As a result, after the reference pulse signal RP is input, if the next reference pulse signal RP is input without any angle pulse signal CP being input, the output terminal 13a of the output terminal 13 of the delay circuit 13 will be As shown in FIG. 4d, it remains at "l", so the output terminal 14a of the A, N-D circuit 14
A pulse signal as shown in Figure e is output.

This pulse signal passes through the OR circuit 7 and is applied to the reset terminal 8a of the flip-flop circuit 8 described above. Turn off the power lanyard 10. 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 applied to the reset terminal 12a of the flip-flop circuit 12, but as another embodiment of the present invention, the angle pulse signal CP is applied to the reset terminal 12a of the flip-flop circuit 12.
Taking advantage of the fact that the ignition/stable signal SP is no longer output when the signal SP is no longer input, as shown in FIG.
It is clear that the same effect can be obtained by applying the ignition pulse signal SP instead of the angle noculus signal CP.

It goes without saying that the above-mentioned two-actuator side 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. Even if the engine is rotating but a multi-angle pulse signal is not input due to a failure or disconnection of the first angle sensor, it is possible to prevent the ignition coil from continuing to be energized, and as a result, the power transistor and This has the effect of being able to prevent the ignition coil from being destroyed.

[Brief explanation of drawings]

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. FIG. 5 is a block diagram showing another embodiment of the 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, i3...Delay circuit. Agent Shin Kuzuno −

Claims (3)

[Claims] (1) A first angle sensor that generates an angle/base pulse signal every time the engine rotates by a predetermined angle, and generates a number of reference/-1' pulse signals corresponding to the number of cylinders during one rotation of the engine. a second angle sensor that calculates the ignition timing according to the operating state of the engine; and a calculation circuit that detects that the angle signal is no longer input even though the engine is rotating. a detection circuit that counts the angle no. 9 pulse signal from the point in time when the reference/base pulse signal is input, and when the counted value matches the ignition timing calculated by the arithmetic circuit; An ignition timing control device comprising ignition control means for generating an ignition signal for cutting off current to an ignition coil when detecting that an angle/arm pulse signal is no longer input. (2) The detection circuit determines that the angle pulse signal is no longer 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 fli control device according to claim 1, characterized in that: (3) A patent claim characterized in that the detection circuit 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 reference pulse No. 117 is input. 1. The ignition timing control device according to item 1.