KR100282896B1 - Apparatus and method for determining misfire of a car - Google Patents

Abstract

According to the present invention, the collector voltage of the power transistor is measured in a state in which acceleration and deceleration and high speed are performed, thereby detecting a collector voltage in an abnormal state and a voltage in a steady state with fuel. Therefore, in order to determine whether or not a fire occurs by comparing with the voltage caused by the secondary ignition during the explosion stroke while operating for each situation of the engine on the basis of the preliminary experiments on the shape of the misfire voltage and the voltage of the normal combustion. An ignition device comprising an ignition coil whose current flow is changed by a power transistor whose ON / OFF state is variable according to a signal, comprising: a voltage detector for detecting a collector voltage of the power transistor according to an ignition signal; A first switch for switching the period of time to integrate the signal of the voltage detector for a period of time; An analog-to-digital converter for converting the integrated signal to digital while the first switch is on; The present invention relates to a misfire determination apparatus and method for a vehicle including a reset switch that is changed from an on state to an off state when a reset signal is output to sample a signal applied from an analog / digital converter in an engine control unit and then initialize the signal of the voltage detector.

Description

Apparatus and method for determining misfire of a car

The present invention relates to an apparatus for determining misfire of an automobile, and to an apparatus and method for misfire determination of a vehicle for monitoring combustion in a cylinder by measuring an ignition coil driving transistor collector voltage during ignition in the absence of fuel that causes misfire. It is about.

Currently, the method of detecting whether the mixer is combusted during the explosion stroke of the electric ignition engine can be known by measuring the combustion pressure or changing the angular velocity during the explosion stroke. Since the method of measuring pressure is very difficult for the ECU to simplify in a real engine, most of them use the change in angular velocity.

However, the prior art has a problem that it is difficult to determine the reference value for judging misfire because the speed difference between normal and abnormal when the engine speed is high does not become very large.

The present invention has been made to solve the above problems, by measuring the collector voltage of the power transistor in the state to accelerate and decelerate and rotate at a high speed, there is no fuel that is a condition that a misfire occurs, that is, a collector in an abnormal state By detecting the voltage at the steady state with the voltage and fuel, it compares with the voltage caused by the secondary ignition during the explosive stroke while operating for each situation of the engine based on the pre-experimental fire shape and the normal combustion voltage shape. The purpose is to determine whether or not a true story.

1 is a block diagram of a misfire determination apparatus according to an embodiment of the present invention;

2 is a timing diagram of secondary ignition according to an embodiment of the present invention,

Figure 3a is a graph measuring the collector voltage of the transistor for applying power to the ignition coil when the ignition is performed at the normal ignition timing,

3B is a graph measuring transistor collector voltage for applying power to an ignition coil when secondary ignition is performed during an explosion stroke without fuel.

3C is a graph measuring the transistor collector voltage for supplying power to the ignition coil when the secondary ignition is performed during the explosion stroke with fuel in.

The present invention to achieve the above object

An ignition device comprising an ignition coil whose current flow is changed by a power transistor whose on / off state is variable according to an ignition signal of an engine control unit,

A voltage detector for detecting a collector voltage of the power transistor according to the ignition signal;

A first switch for switching the period of time to integrate the signal of the voltage detector for a period of time;

An analog-to-digital converter for converting the integrated signal to digital while the first switch is on;

In order to initialize the signal of the voltage detector again after sampling the signal applied from the analog-to-digital converter in the engine control unit is characterized in that it consists of a reset switch that is changed from the on state to the off when the reset signal output.

Hereinafter, with reference to the accompanying drawings will be described in detail the most preferred embodiment of the present invention.

Referring to the configuration of the present invention with reference to Figure 1 as follows.

An ignition coil GC whose current flow is changed by the power transistor 50 whose ON / OFF state is changed according to the ignition signal of the microcomputer 10 and the collector voltage of the power transistor 50 are detected according to the ignition signal The voltage detector 60, the analog switch 30 for switching the period of time to integrate the signal of the voltage detector 60 for a predetermined period, and the analog switch 30 converts the integrated signal to digital After sampling the signal applied from the A / D converter 20 and the A / D converter 20 by the microcomputer 10, the signal is reset from the on state to the off state in order to reset the signal of the voltage detector 60 again. It consists of a reset switch 40 which is variable and a capacitor C which accumulates a voltage applied through the analog switch 30 for a predetermined time.

The voltage detector 60 includes a resistor R1 having one terminal connected to a coupling terminal of the power transistor 50 and the ignition coil GC, an anode connected to the other terminal of the resistor R1, and a cathode connected to the battery terminal. The diode is connected, and the diode anode and a resistor R2 having one terminal connected to the other terminal of the resistor R1.

The resistors R1 and R2 are for voltage drop to lower the voltage, and adjust the voltage drop ratio of R1 / R2 to about 10 to 20 to be lowered below 5V.

Referring to Figure 2 the operation of the present invention made as described above is as follows.

First, the fuel is put into operation to analyze the transistor collector voltage shape at steady state.

Therefore, when the driver supplies power for engine operation, the microcomputer 10 injects a predetermined fuel to an engine cylinder (not shown), and outputs a predetermined ignition signal for burning the injected fuel.

The power transistor 50 is turned on / off in accordance with the ignition signal output from the microcomputer 10 to turn on / off the primary current of the ignition coil G.C.

Accordingly, when the primary coil of the ignition coil 20 is turned off, a large voltage is induced to the secondary coil, thereby causing a discharge from the spark plug attached to the engine cylinder (not shown) to burn the injected fuel.

As this affects the primary coil again, the microcomputer 10 compares the shape of the voltage flowing through the primary coil converted by the A / D converter 20 by the voltage drop by the resistor R1.

However, in the present invention, the analog switch 30 is kept on so that voltage is accumulated in the capacitor until the secondary ignition is performed in the explosion stroke without analyzing the voltage by integrating the voltage at the primary ignition timing.

The reason for the voltage analysis at the second ignition time without performing the voltage analysis at the first ignition time as described above is very difficult to analyze because the data of the voltage analysis at the first ignition time do not differ significantly depending on the misfire or not. Because.

At this time, the transistor collector voltage after the secondary ignition is shown in FIG. 3C.

In addition, when the transistor collector voltage after the secondary ignition is analyzed without adding fuel to intentionally cause misfire, it appears as shown in FIG. 3B.

The voltage of FIG. 3b here is not only shown much higher than the voltage of FIG. 3c, but is also wider first.

In FIG. 3B, a high voltage and a large rising area mean that the sparking condition is difficult. On the other hand, in FIG. 3C, a low rising voltage and a small area mean that discharge is easily performed.

Eventually, a lot of ions are generated by the combustion process, which shows that the conditions are likely to spark.

Therefore, when monitoring by varying each engine condition on the basis of the voltage shape after the secondary ignition obtained by intentionally causing misfire or experimenting with fuel normally, if the voltage shape is similar to that of FIG. It is determined to be normal combustion.

According to the present invention, the actual engine is operated based on the transistor voltage signal after the second explosion ignition during the misfire simulation to compare the voltage after the second ignition with the explosion stroke, so that the misfire can be determined. The misfire is judged even in difficult situation, so it can be effectively used for engine development.

Claims (4)

An ignition device comprising an ignition coil whose current flow is changed by a power transistor whose on / off state is variable according to an ignition signal of an engine control unit, A voltage detector for detecting a collector voltage of the power transistor according to the ignition signal; A first switch for switching the period of time to integrate the signal of the voltage detector for a period of time; An analog-to-digital converter for converting the integrated signal to digital while the first switch is on; A misfire determination device for a vehicle comprising a reset switch that is changed from an on state to an off state when a reset signal is output in order to initialize a signal of a voltage detector after sampling a signal applied from an analog / digital converter by an engine control unit. The diode of claim 1, wherein the voltage detector includes: a first resistor having one terminal connected to the power transistor and the ignition coil coupling terminal; an anode connected to the other terminal of the first resistor and a cathode connected to the battery terminal; and a diode anode. And a second resistor having one terminal connected to the other terminal of the first resistor, wherein the first resistor and the second resistor are for a voltage drop to lower the voltage and are about 10 to about 20 to be lowered below 5V. Misfire determination device for a vehicle, characterized in that to match the voltage drop ratio of the second resistance. A first step of igniting once more in an explosion stroke after performing ignition at the normal ignition timing and comparing the transistor collector voltage when the misfire occurs in this state with the transistor collector voltage in a non-fire condition; In fact, if the transistor collector voltage generated after the second ignition in the explosion stroke by rotating the engine for each driving region is similar to the transistor collector voltage shape in the case of misfire analyzed in the second stage, How to judge a true story. The method according to claim 3, wherein the transistor collector voltage is detected in the secondary ignition state in the explosion stroke without comparing the transistor collector voltages at the normal ignition timing for easy comparison.

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