KR100272731B1 - A method and device for diagnosing the engine at the automobile - Google Patents

Abstract

PURPOSE: Examining method and device for an engine are provided to examine state of the engine through detecting transformation of breakdown voltage according to mixture self-ionization in a combustion chamber of a cylinder by using a spark plug. CONSTITUTION: In a self-ionization state of mixture in a combustion chamber, voltage is continuously supplied for obtaining a breakdown voltage. According to the supplied voltage, the mixture is self-ionized under specific temperature and pressure while having ion current. Then, a voltage forming a point of inflection is detected according to the self-ionization. Therefore, pressure in the combustion chamber is detected. Then, the detected breakdown voltage is compared with a reference breakdown voltage for displaying a calculated value.

Description

Diagnostic method of the engine and its device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine diagnostic method and apparatus thereof, and more particularly, to detect breakdown vo1tage deformation effects due to mixed gas self-ionization in a combustion chamber in a cylinder. The present invention relates to an engine diagnosis method and apparatus for detecting knocking, misfire, etc. to protrude information on a pressure waveform and an engine state.

Engine Diagnostics in a vehicle checks the explosion performance of the engine and obtains data for optimizing it, which can be divided into detection of knocking and detection of misfire.

In particular, the detection system of the misfired state includes on-board diagnosics II (OBDII) or environmental protection agency (EPA), which is expected to be implemented in various countries such as the United States and Europe, which strictly regulates the regulation of air pollution and noise by exhaust gas. It is required to be mounted on a vehicle under the provisions of

BACKGROUND ART Engine diagnostic methods widely used in the related art include pressure measuring methods, ion current testing methods, combustion heat detection methods, and the like. Among them, the pressure measuring methods are widely used.

The pressure measurement method uses a piezo sensor and an EM sensor. The piezo sensor can protrude an accurate pressure waveform on the oscilloscope, but it is too expensive and has a disadvantage of forming a hole in the engine. .

In addition, the ion current inspection method is based on the ion concentration of the gas, which is not related to temperature and pressure in the engine, and thus, accurate data cannot be obtained.

As the engine diagnosis system, a device for detecting knocking has developed a device for measuring and detecting vibration or sound waves generated from an engine at BOCH, which requires a separate sensor and distinguishes each cylinder of the engine. Could not be measured.

In addition, the apparatus for measuring vibration of the engine is easy to process signals, but expensive, and the apparatus for measuring sound waves generated from the engine is difficult to process signals. There is a problem that can not calculate the correct data.

In addition, a device for detecting knocking using an SAAB ion current must be amplified because the detected signal is too small, and a countermeasure for preventing noise is needed.

In addition, the method of detecting and detecting a change in the crankshaft rotation speed in detecting misfire cannot be applied to an engine of six cylinders or more, it is difficult in signal processing, and a detection error occurs on rough roads. There are disadvantages.

In addition, the exhaust gas pulse measuring method is accurate and good in the detection result, but it is impossible to measure when the engine idle rotates, and also has a short life and a high cost. In addition, the pressure measurement method can protrude an ideal result in the self-diagnosis, but there is a problem that the engine must be processed and the applied sensor is expensive.

According to the self-diagnosis method and apparatus of the engine according to the prior art, firstly, the equipment is expensive, and secondly, the engine must be separately processed, and thirdly, the engine cannot be diagnosed without being influenced by surroundings. There was a problem that the misfire cannot be measured together.

The present invention was invented to solve the above problems, and an object of the present invention is to provide a spark plug having a blackdown voltage deformation effect due to mixed gas self-ionization in a combustion chamber in a cylinder. It detects knocking or misfire of engine and protrudes into pressure waveform to diagnose engine. Firstly, it is easy to apply to engine, and the signal generated is large so that no separate amplifier is needed. Engine abnormality can be detected, the structure of the device is simple, and secondly, it is possible to determine the air-fuel ratio and misfire degree of fuel without being limited by the number of cylinders of the engine, and to quickly affect the response and the road condition. It is an object of the present invention to provide an engine diagnostic method and apparatus for easily processing a signal.

In order to achieve the above object, the present invention includes a high voltage generation step of continuously supplying a voltage in order to obtain a block down voltage of the mixed gas in the combustion chamber in the self-ionization state; A self-ionization generating step of self-ionizing the mixed gas with ion current at a constant temperature and pressure according to the voltage supplied in the high voltage generating step; A blockdown voltage detection step of detecting a voltage forming an inflection point according to self-ionization in the self-ionization generation step; And a signal processing step of displaying a value calculated by comparing and processing the blockdown voltage and the reference blockdown voltage detected in the blockdown voltage detection step.

In addition, the present invention, the high-voltage generator for generating a high voltage of -20,000V and using the secondary voltage of the generator or battery; A self-ionization and blockdown voltage detection unit connected to the high voltage generation unit and receiving a high voltage; The engine is characterized in that the voltage is applied to the self-ionization and the blockdown voltage detection unit connected in parallel with the high voltage generating unit is applied to the reference value based on this process and is configured as a signal processing unit forming a divider unit It is a diagnostic device.

1 is a view showing an execution process of a diagnostic method of an engine according to an embodiment of the present invention.

2 is a self-ionization characteristic curve of a gas applied to the present invention.

3 is a circuit diagram for explaining an engine diagnostic apparatus according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: high voltage generation step 12: self-ionization step

14: blockdown voltage detection step 16: signal processing step

20: high voltage generator 22: self-ionization and black down detection unit

24: signal processor 26: divider unit

Rl, R2, R3: Resistor Dl, D2: Diode

SP: Spark Plug

Hereinafter, the most preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

1 is a diagram illustrating an execution process of a diagnostic method of an engine according to an exemplary embodiment of the present invention.

The diagnostic method of the engine of this embodiment includes a high voltage generation step (10); Magnetic ionization generating step (12); A blockdown voltage detection step 14; And the procedure of the signal processing step 16 is performed.

The present invention is to self-ionize the mixed gas in the combustion chamber of the cylinder of the engine, which will be described with reference to the self-ionization characteristic curve shown in FIG.

The gas generally has a proportional ion current up to a constant voltage and at this constant voltage it has an inflection point. The inflection point is different depending on the type of gas (A, B, C), and each point (Vl, V2, V3) is the point where the ionization starts. Therefore, before reaching the inflection point (V1, V2, V3) refers to a state that is not ionized. That is, the state of a point in the A gas curve, b point in the B gas curve, and c point in the C gas curve.

The voltage up to this inflection point is called a blockdown voltage, and each ion current corresponding to it is a function of pressure and temperature. Therefore, the pressure change can be calculated through the ion current and the blackdown voltage generated at this time.

On the basis of this, returning to the first degree, the high voltage generation step 10 is to continuously supply the voltage to obtain a block down voltage of the mixed gas in the combustion chamber in the self-ionization state.

The self-ionization generation step 12 refers to the self-ionization of the mixed gas with ion current under a constant temperature and pressure according to the voltage supplied in the high voltage generation step 10.

The blackdown voltage detection step 14 refers to detecting a voltage forming an inflection point according to self-ionization, and through this, it is possible to estimate the pressure in the combustion chamber.

The signal processing step 16 displays a value calculated by comparing and processing the blockdown voltage and the reference blockdown voltage detected in the blockdown voltage detection step 14.

3 is a circuit diagram for explaining an engine diagnosis apparatus according to an embodiment of the present invention, which includes a high voltage generator 27, a self-ionization and a blockdown voltage detector 22, and a signal processor 24. It is composed.

The high voltage generator 20 generates a high voltage of -20,000 V, and uses a secondary voltage of a generator or a battery for this purpose. The self-ionization and blockdown voltage detection unit 22 and the signal processing unit 24 are connected in parallel to the high voltage generator 27, and the resistor R1 is connected between the connection point Pl of the signal processing unit 24. There is a diode Dl between the connection point P2 of the self-ionization and the blockdown voltage detection unit 22.

The self-ionization and blockdown voltage detection unit 22 uses a spark plug SP mounted toward the combustion chamber in the engine. That is, the blockdown voltage according to the self-ionization in the combustion chamber detected through the spark plug SP is detected, and the blockdown voltage according to the self-ionization of the mixed gas is the value of the ion current according to the pressure change in the combustion chamber. Since the specific voltage value is applied according to the abnormal pressure caused by knocking and misfire of the cylinder. Accordingly, the signal processing unit 24 connected in parallel with the self-ionization and blockdown voltage detection unit 22 from the high voltage generator 20 according to the voltage applied to the self-ionization and blockdown voltage detection unit 22. The voltage is applied and processed based on the comparison with the reference value.

However, when the voltage applied from the high voltage generator 20 is applied as it is, the signal processor 24 constitutes a divider unit 26 that distributes the damage due to the high voltage. In the present embodiment, the resistors R2 and R3 are respectively configured before and after the point P3 to which the signal processing unit 24 is connected in the divider unit 26, and through this, each voltage is down so that the signal processing unit 24 Is applied. In the present embodiment, the resistance R2 is preferably 10GΩ and the resistance R3 is 10kΩ.

On the other hand, the self-ionization and the blockdown voltage detection unit 22 is connected to the distributor while constituting the diode (D2), is receiving a power source that generates a spark of the spark plug (SP). Therefore, the diodes D1 and D2 are for protecting the respective circuits by preventing the high voltage supplied from the high voltage generator 20 and the distributor from flowing back to each other.

Therefore, according to a preferred embodiment of the present invention, the power generated by the high voltage generator 20 is to keep the current down while maintaining the voltage at the resistor (Rl), which is the self-ionization and blackdown voltage detection unit 22 It is such that the spark plug SP is not affected. In this embodiment, it is preferably 100 ns. Therefore, the high voltage power generated by the high voltage generator 20 does not affect the spark plug SP while the power generated by the distributor is applied to the self-ionization and the blockdown voltage detector 22. The magnetic ionization and the blockdown voltage detector 22 and the signal processor 24 are separately applied. Since the voltage applied to the signal processor 24 is the same as the voltage applied to the spark plug SP, it is influenced by the voltage received by the spark plug SP. In addition, since the spark plug SP receives a different voltage value according to the pressure in the combustion chamber, the signal processor 24 can obtain a pressure waveform according to the pressure change in the combustion chamber of the cylinder. You can also get information about engine failures directly. As a result, engine misfire and knocking can be detected, pre-ignition can be detected, and the braking average effective pressure, that is, the engine output and thermal efficiency can be measured.

As described above, the engine diagnosis method and the apparatus according to the present invention, firstly, not only does not require a separate sensor and equipment, but also does not require processing for mounting the sensor to the engine, and secondly, the measuring range is knocked. Alternatively, all abnormalities in the engine can be detected, not limited to misfire detection. Third, information on pressure changes in the cylinder can be obtained without using a pressure sensor. Therefore, direct information on pressure waveforms or engine abnormalities can be obtained. It can be effective.

Since what has been described above is merely a mere example in all respects, the present invention should not be limitedly interpreted based on this. Therefore, modifications and equivalent embodiments that fall within the true spirit and scope of the present invention shall fall within the claims of the present invention.

Claims (10)

A high voltage generating step (10) of continuously supplying a voltage in order to obtain a block down voltage in the self-ionization state of the mixed gas in the combustion chamber; A self-ionization generating step 12 in which a mixed gas is self-ionized with an ion current under a constant temperature and pressure according to the voltage supplied in the high voltage generating step 10; A blockdown voltage detection step 14 of detecting a voltage forming an inflection point according to the self-ionization in the self-ionization generating step 12; And a signal processing step (16) for displaying a value calculated by comparing and processing the blockdown voltage and the reference blockdown voltage detected in the blockdown voltage detection step (14). A high voltage generator 20 for generating and applying a high voltage; A self-ionization and blockdown voltage detection unit 22 connected to the high voltage generation unit 20 to detect a block down voltage while applying a high voltage to self-ionize the mixed gas; It is composed of a signal processor 24 for applying a voltage corresponding to the voltage applied to the self-ionization and the blockdown voltage detection unit 22 connected in parallel in the high voltage generation unit 20 and compares it with a reference value based on this. An engine diagnostic apparatus. The engine diagnostic apparatus according to claim 2, wherein the high voltage generator (20) generates a power of -20.000V using the secondary voltage. 3. The engine diagnostic apparatus according to claim 2, wherein the high voltage generator (20) constitutes a resistor (Rl) before being connected to the self-ionization and block down voltage unit (22). 5. The engine diagnostic apparatus according to claim 4, wherein the resistance Rl is 100 kW. 3. The apparatus of claim 2, wherein the self-ionization and blockdown voltage portion (22) is a spark plug (SP). 3. The engine diagnostic apparatus according to claim 2, wherein the signal processing unit (24) configures the divider unit (26) before connection with the high voltage generation unit (20). 8. The engine diagnostic apparatus according to claim 7, wherein the divider section (26) constitutes a resistor (R2) (R3) before and after the connection point (P3) of the signal processing section (24). 9. The engine diagnostic apparatus according to claim 8, wherein the resistor (R2) is 10GΩ. 9. The engine diagnostic apparatus according to claim 8, wherein the resistance (R3) is 10 kΩ.

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