JPS61244873A - Low voltage distribution type ignition device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of erroneous ignition, by a method wherein a trouble on an ignition signal distribution circuit is detected from outputs from an ignition signal generating circuit and an ignition signal distributing circuit, and an ignition signal distributing circuit is reset during the occurrence of a trouble. CONSTITUTION:An ON-OFF signal from an ignition coil responding to the ignition timing of an engine is generated by an ignition signal generating circuit 31. A cylinder discriminating signal from a cylinder discriminating sensor 33 is inputted through a waveform shaping circuit 34 to a latch circuit 35. In which case, if no signal is inputted from a trouble detecting circuit 36, a signal V1st is fed to an ignition signal distributing circuit 32 through a circuit 35, and a circuit 32 is reset to decrease all outputs to 'L'. A next inputting ignition signal V1G and the following signals are orderly distributed so as to match each ignition timing. Beside, when an output signal from the circuit 32 is inverted, from an ignition signal V1G and an output signal from an OR circuit 37, inversion of a signal is detected, an output from the circuit 36 is increased to 'H', and the circuit 32 is reset to decrease all output signals to 'L'. This prevents sparks from flying to ignition plugs 4a-4d.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an ignition system for an internal combustion engine, and in particular, the present invention relates to an ignition system for an internal combustion engine, and in particular, the ignition system eliminates a power distribution device that distributes high voltage generated in an ignition coil to spark plugs of each cylinder of the engine. The present invention relates to an ignition device that directly supplies the output voltage of a coil to a spark plug.

[Background of the invention]

In the conventional ignition system, as shown in Fig. 2, the high voltage generated on the secondary side of the ignition coil l by the disconnection of the interrupter 2 is distributed to the spark plugs 48 to 4d of each cylinder by the power distributor 3. Ta. That is, the rotor 3a of the power distributor 3 rotates in synchronization with the rotation button of the engine, and when the rotor 3a comes to the position of the power distribution terminals 3b to 3e, the interrupter 2 is opened and the ignition coil 1 is turned on.
A high voltage is generated on the secondary side of the spark plug, which causes a spark to fly to the spark plug. In this case, the rotor 3a and each terminal 3b to 3e
There is a gap between the spark plugs, and during ignition, discharge occurs in this area, wasting the discharge energy supplied to the spark plug, and reducing performance at high revolutions.

Therefore, as shown in Fig. 3 and Fig. 4,
43143.51-49334 and the like have been proposed. Figure 3 shows one in which the secondary sides of two sets of ignition coils 10 and 11 are connected directly to the spark plugs to generate spark discharge simultaneously in the cylinders of the engine's compression stroke and exhaust stroke, and Figure 4 shows each spark plug 4a. , 4b have ignition coils 10, 11, respectively, and omit the power distributor to provide a highly efficient ignition system with little loss. Note that 12 and 13 in the figure are interrupters.

However, these require as many interrupters as the number of ignition coils to intermittent the primary current of the ignition coil and generate high voltage on the secondary side (in the case of Fig. 3, half the number of cylinders, in the case of Fig. 4). In particular, it is impossible to convert high-voltage distribution type ignition systems to these low-voltage distribution type ignition systems, depending on the number of cylinders.

Therefore, in order to easily modify a high-voltage distribution type ignition system to a low-voltage distribution type ignition system, the number of the interrupters is set to one, and the signal obtained by opening and closing this interrupter is set to a specific ignition signal different from the ignition signal. It is necessary to distribute the ignition signal based on a cylinder discrimination signal that detects the cylinder.

[Purpose of the invention]

An object of the present invention is to match the ignition timing of each of a plurality of ignition coils directly connected to a spark plug.
It is an object of the present invention to provide a low voltage distribution ignition device that distributes ignition signals based on a cylinder discrimination signal.

[Summary of the invention]

According to the present invention, an abnormality in the ignition signal distribution circuit is detected from the output of the ignition signal generation circuit and the output of the ignition signal distribution circuit, and when an abnormality occurs, the ignition jδ distribution circuit is reset.
It is possible to realize a low-voltage distribution ignition device that does not cause erroneous ignition even if the output of an ignition signal distribution circuit does not match the ignition timing of a plurality of ignition coils directly connected to a spark plug for some reason.

[Embodiments of the invention]

Figure 1 is a configuration diagram of an embodiment of the present invention. The ignition signal obtained by the ignition signal generation circuit 31 is sent to the ignition signal distribution circuit 32 and an abnormality detection circuit 36 that detects an abnormality in the ignition signal distribution circuit 32.

On the other hand, the cylinder discrimination signal obtained by the cylinder discrimination sensor 33 is shaped by the waveform shaping circuit 34, and when an abnormality occurs, the cylinder discrimination signal is
The ignition signal is sent to the ignition signal distribution circuit 32 via the latch circuit 35 holding the reset signal No. 2, the ignition signal distribution circuit 32 distributes the ignition signal based on the cylinder discrimination signal, and the ignition signal is directly connected to the spark plug. This is in addition to the plurality of ignition coil driving power transistors 21-24. Also, the signals applied to the power transistors 21 to 24 are
The abnormality detection circuit 36 detects an abnormality in the output signal of the ignition signal distribution circuit 32 from the output signal of the OR circuit 37 and the ignition signal, and if there is an abnormality, the latch circuit 35 Since the reset signal of the ignition signal distribution circuit 32 is held until the cylinder signal of 2 is input, no erroneous ignition occurs.

The operation of the embodiment of the present invention will be explained below.

In the ignition signal generation circuit 31, an ignition coil ON-OF'F signal corresponding to the ignition timing of the engine is generated. Further, the cylinder discrimination signal V obtained from the cylinder discrimination sensor 33 is waveform-shaped by a waveform shaping circuit 34 and sent to a latch circuit 35. If no signal is input from the abnormality detection circuit 36, the cylinder discrimination signal V1. ．． is sent to the ignition signal distribution circuit 32 via the latch circuit 35,
Reset the ignition signal distribution circuit 32 and set all outputs to -Low
' to. Then, the ignition signal VXa that is input next is distributed sequentially to match each ignition timing, and this output signal drives the power transistors 21 to 24 to generate a high voltage on the secondary side of the ignition coils 14 to 17. This causes spark discharge to occur in the spark plugs 4a to 4d, igniting the air-fuel mixture.

At this time, if the output signal of the ignition signal distribution circuit 32 is inverted for some reason, the ignition signal VIG and the OR circuit 37
The abnormality detection circuit 36 detects the opposite meaning of the signal from the output signal of
The output of the latch circuit 35 becomes ')high' and the output of the latch circuit 35 also remains 'high' until the next cylinder discrimination signal V 1 @t is input, so the ignition signal distribution circuit 32 is reset and all output signals are ')'. Low”. Therefore, sparks do not fly to the spark plugs 4a to 4d, and erroneous ignition does not occur.

FIG. 5 is a block diagram of the ignition signal distribution circuit 32.
It consists of a multiplier circuit 41 and a ring counter 44. Also the 6th
The figure is a diagram showing the operation timing. The ignition signal distribution method will be explained below. Ignition signal generation circuit 31
In addition to the pulse doubling circuit 41, which generates short-term pulses at the rising and falling edges of the ignition signal, generated by a circuit breaker (for example, an interrupter built into a power distribution device), the pulse doubling circuit 41
Doubler circuit 41 (7) output pulse V! A2 is used as a clock to drive the power transistors 21 to 24 with voltages sequentially generated at the outputs QG, Q2, Q4, and Qs of the shift register 42 in addition to the ring counter 44 composed of the shift register 42 and the NOR circuit 43. It is configured. Also, the output v1 of the cylinder discrimination sensor 33. ．． is shaped by the waveform shaping circuit 34 and sent to the latch circuit 35 as the cylinder discrimination signal v1.1, and if the output of the abnormality detection circuit 36 is "@LOW", the latch circuit 35 outputs the cylinder discrimination signal v1.
□ Output as is. This cylinder discrimination signal V, @*
to reset the ring counter 44 and set all outputs of Qo and Qa to -Low level.Ring counter 4
4 is the clock after reset (the ignition signal is “l(high”)
Counting is started from the output point A of the pulse doubling circuit 41 that appears when

Qo is the ignition signal V! after the first cylinder ignites. . ga”)(igh
When ``,'' becomes ``)(high'', the third cylinder can be ignited by driving the power transistor 21 with this signal.Next, Q! becomes ``)(igh'') after the third cylinder ignites. Since this is the time when the ignition signal becomes @H=gh#, this is the signal for the 4th cylinder.Similarly, Q4 is the signal for the 2nd cylinder, Qa is the signal for the 1st cylinder, and hereafter QG, Q=
, Q4, and Q- to sequentially drive the power transistors 21, 22, 23, and 24, ignition can be performed according to the ignition order of the engine. That is, ignition can be performed according to a series of ignition signals.

FIG. 7 shows one embodiment of the latch circuit, which is composed of an R87 lip-flop 51 and an OR circuit 52.

FIG. 8 is an explanatory diagram of the operation of the latch circuit of FIG. 7.

When the output terminal of the abnormality detection circuit 36 is "LOIV", R
The output Q of the S flip-flop 51 becomes "Low" at the first cylinder discrimination signal Vl, , and continues to be "Low" thereafter. Therefore, the output of the OR circuit 52 is the cylinder discrimination signal v1. ．． is output in the same format. Here, if the output of the abnormality detection circuit 36 becomes @High# even for a moment, the output Q of the RS flip-flop 51 becomes the next cylinder discrimination signal vl @
In order to hold "@High" until * is input,
The output of the OR circuit 52 also becomes @)(igh", and all the outputs of the ignition signal distribution circuit 32 become @I, ow #.

FIG. 9 shows an embodiment of an abnormality detection circuit using an exclusive OR circuit. Since the Exclusive OR circuit outputs "High" when the input signals are different, the inversion of the output signal of the ignition signal distribution circuit 32 can be detected by this circuit.

Fig. 1O shows the @High” portion of the ignition signal, and Fig. 11 shows the “LOW” portion of the ignition signal, showing the ignition signal distribution circuit 32.
This is an embodiment of an abnormality detection circuit that detects the reversal of the output signal of the ignition signal distribution circuit.If the time delay C circuit becomes complicated between the ignition signal and the output signal of the ignition signal distribution circuit, the operation time of the circuit becomes longer.
This is effective when there is a time delay).

The operation of the circuit shown in FIG. 10 will be explained with reference to FIG. 12. In Fig. 10, the ignition signal is changed by increasing the resistance value of resistor R1 to increase the charging time constant of capacitor C, and decreasing the resistance value of resistor R2 to decrease the discharging time constant of capacitor C. Let TitWTat be the relationship between the time Tit when the signal is "high" and the time Tax when the OR circuit 37 is "high".If the output of the ignition signal distribution circuit 32 is normal in this state, the output of the AND circuit 53 is @I, Ow # However, if the output of the ignition signal distribution circuit 32 is inverted, it becomes ``)(igh'', and the output of the latch circuit 35 also becomes ``)(igh'', so the ignition signal distribution circuit 32 is reset. It is clear that the circuit shown in Fig. 11 can also be realized by setting the relationship between the time TLI during which the ignition signal is "LoW" and the time TL2 during which the output of the OR circuit 37 is LOW# as Th+WTci. be.

In the embodiment of the present invention, one ignition coil is connected to each of the four cylinder spark plugs, but as shown in FIG. The same applies to those whose secondary side is directly connected to the ignition plug, or when a conventional ignition system is modified to use a low-voltage distribution type ignition system.Also, even in the case of 5 or more cylinders, the number of ring counters and abnormality detection Needless to say, this problem can be solved simply by increasing the number of input terminals of the OR circuit that generates the input signal for the circuit.

In this way, the present invention detects an abnormality in the ignition timing based on the ignition signal and the output signal of the ignition signal distribution circuit that distributes the ignition signal in a predetermined order, and prevents the ignition coil from generating any high voltage in the event of an abnormality. This prevents accidental ignition. In addition, the interrupter used up until now can be used as a means for generating ignition signals, and the power distributor can be used as a means for determining cylinders, so a conventional high-voltage distribution type ignition system can be converted to a low-voltage distribution type ignition system by simply adding a circuit. It becomes possible to remodel.

〔Effect of the invention〕

As described above, according to the present invention, even if for some reason the ignition timing of each of the ignition coils having a plurality of IIs differs from the ignition timing required by the engine, erroneous ignition will not occur, so even in the worst case, the engine will not be damaged. It is possible to provide safety functions that would not otherwise be available.

[Brief explanation of the drawing]

1 and 13 are circuit configuration diagrams of an embodiment of the present invention, and FIG.
Figures 3 and 4 are block diagrams of a conventional ignition device, Figure 5 is a block diagram of an ignition signal distribution circuit according to an embodiment of the present invention, and Figure 6 is a diagram for explaining the operation of the ignition signal distribution circuit. , FIG. 7 is a block diagram of the latch circuit according to the embodiment of the present invention, FIG. 8 is a diagram for explaining the operation of the latch circuit, and FIGS. 9, 10, and 11 are diagrams of the abnormality detection circuit according to the embodiment of the present invention. The configuration diagram and FIG. 12 are diagrams for explaining the operation of the abnormality detection circuit. 31... Ignition signal generation circuit, 32... Ignition signal distribution circuit, 33... Cylinder discrimination sensor, 34... Waveform shaping circuit, 35... Latch circuit, 36... Abnormality detection circuit, 14 ~17...Ignition coil, 21~24・
...puff -transistor.

Claims (1)

[Scope of Claims] 1. An ignition signal generating means for generating an ignition signal in accordance with the ignition timing of the engine, a cylinder discriminating means for periodically discriminating a reference cylinder of the engine, and a discriminating signal of the cylinder discriminating means. ignition signal distribution means for distributing the ignition signal in a predetermined order and controlling the switching means connected to the primary sides of the coils of a plurality of ignitions. a detection means for detecting an abnormality in the signal; and a control means for resetting the ignition signal distribution means using the detection signal of the abnormality detection means and holding the reset signal until the next cylinder discrimination signal is output. A low-voltage distribution type ignition device characterized by: 2. The low voltage distribution type ignition device according to claim 1, wherein the abnormality detection means detects from the output signal of the ignition signal generation means and the output signal of the ignition signal distribution means.