KR20070028677A - A fuel pump and driver diagnosis system of liquified petroleum gas injection vehicle and method thereof - Google Patents

Abstract

A fuel pump and driver diagnosis system of an LPI(Liquefied Petroleum gas Injection) vehicle and a control method thereof are provided to prevent erroneous diagnosis by diagnosing the abnormality of components associated with the operation of a fuel pump. A fuel pump and driver diagnosis system of an LPI vehicle, comprises an interface unit(10), a control unit(20), a motor driver(30), a switching unit(40), a first reference value set unit(50), a first comparator(60), a second comparator set unit(70), a second comparator(80), and an abnormality detection unit(90). The interface unit interfaces information detected by sensors of the vehicle. The control unit determines the quantity of fuel suitable for the current operation condition in accordance with the information detected by the interface unit, and outputs a PWM control signal by driving the operation speed of a fuel pump. The motor driver is arranged to drive the fuel pump in accordance with the PWM control signal applied from the control unit. The switching unit converts DC voltages into three phase voltages and drives the fuel pump by being switched in accordance with the PWM signal applied from the motor driver. The first reference value set unit has a table where reference PWM signals for each phase for driving the fuel pump are set in accordance with the fuel injection quantity condition. The first comparator detects PWM control signals for each phase output from the motor driver to the switching unit, compares the detected signals with the reference PWM signals set in the first reference value set unit, and outputs the comparison result. The second comparator compares the operation speed of the fuel pump and the reference speed set in the second reference value set unit. The abnormality detection unit diagnoses the signals applied from the first comparator and the second comparator, performs self diagnosis on the disconnection of signal lines or faults of the fuel pump, and provides the self diagnosis result to the control unit.

Description

FUEL PUMP AND DRIVER DIAGNOSIS SYSTEM OF LIQUIFIED PETROLEUM GAS INJECTION VEHICLE AND METHOD THEREOF}

1 is a schematic configuration block diagram of a fuel pump and a diver diagnostic apparatus of a vehicle to which the Elpia system is applied.

2 is a flow diagram of an embodiment of performing fuel pump and driver diagnostics in an Elpia system applied vehicle in accordance with the present invention.

Figure 3 is a block diagram for a fuel pump diagnosis apparatus in a vehicle applying a conventional Elpiai system.

<Explanation of symbols for the main parts of the drawings>

10: interface unit 20: control unit

30: motor driver 40: switching unit

50: first reference value setting unit 60: first comparator

70: second reference value setting unit 80: second comparator

90: abnormal detection unit M: fuel pump motor

The present invention relates to a vehicle to which the Elpia system is applied. More specifically, the fuel pump and the fuel pump of the Elpia vehicle to provide reliability and convenience of self-diagnosis by diagnosing abnormality of the fuel pump and the fuel pump motor driver. And a driver diagnostic apparatus and a control method thereof.

In general, LPG Injection (LPG Injection), which is applied to LPG vehicles, is equipped with a fuel pump in a cylinder and presses fuel by driving the fuel pump to maintain an injector while maintaining a liquid phase. It means the LPG MPI (LIQUIFIED PETROLEUM GAS MULTI POINT INJECTION) system to inject the calculated amount to each cylinder through.

LPG fuel consists of C3 Hydrocarbon (propane) and C4 Hydrocarbon (butane). In Korea, refineries supply mixed propane and butane contents according to the season to ensure starting and operation. have.

That is, in summer, butane is 100%, in winter, the ratio of butane and propane is mixed at 70% to 30%, and in the season, the ratio of butane and propane is mixed at 80 to 90% vs. 10 to 20%. .

The LPG fuel increases its volume by 250 times when the liquid fuel phase changes into the gas phase due to temperature rise or pressure drop.

Therefore, if the phase change of the liquid fuel occurs during engine operation, the engine stop occurs because the amount of fuel actually introduced into the combustion chamber is only 1/250. Therefore, the LPG fuel image is caused by the radiant heat of the engine during driving (including children). The fuel in the cylinder is injected by pressurizing it through the fuel pump so that no change occurs.

The engine control means installed in the vehicle to which the Elpia system is applied determines the fuel injection amount and the rotational speed of the fuel pump according to the pressure and temperature of the fuel line connecting the cylinder and the injector, and the operating speed through the fuel pump driver. It controls the driving of fuel pump by output of pulse width modulation (PWM) signal.

In the vehicle to which the Elpia system is applied, the engine stops because the normal fuel is not pressurized in the combustion chamber when a failure of the fuel pump or a failure of the fuel pump driver occurs, thereby causing a fatal accident. There is a problem that threatens the driver and passengers.

Therefore, in order to prevent such a situation in advance, the self-diagnostic function is applied by monitoring the operation of the fuel pump in the fuel pump driver which drives the driving of the fuel pump.

 As shown in FIG. 3, the control unit 30 is enabled by the set predetermined oscillation frequency output from the oscillator 1, and in this state, the control unit 30 detects the engine speed from the ECU which is the engine control means. Then, the rotational speed of the motor is detected from the fuel pump and compared.

As a result of the comparison, it is determined whether the difference between the engine rotational speed and the rotational speed of the motor exceeds the range of the set reference value, preferably within 30%, and when the fuel pump is normally operated within the range of the set reference value. A signal for normal driving, for example, a frequency of 5 Hz is output and applied to the base terminal of the transistor Q1.

Accordingly, the transistor Q1 operates on / off at a frequency of 5 Hz to be applied to apply a signal for self-diagnosis of the fuel pump to a microcomputer (not shown).

However, if it is determined that the difference between the engine speed and the motor rotation speed exceeds the range of the set reference value, it is determined that there is an error in the driving of the fuel pump and outputs a signal for abnormal driving, for example, a frequency of 10 Hz. To the base terminal of the transistor Q1.

Accordingly, the transistor Q1 operates on / off at a frequency of 10 Hz to be applied to apply a signal for self-diagnosis of the fuel pump to a microcomputer (not shown).

The microcomputer counts the number of occurrences of the signal for abnormal driving of the fuel pump and outputs a fault code of the fuel pump when the counter is set to a predetermined number of times, approximately 50 times, so that the driver can perform a repair replacement.

However, there are various causes of the failure of the fuel pump, for example, short circuit or disconnection of signal line, failure of the driver, failure of the fuel pump, etc. Diagnose only the failure of the pump.

Therefore, even if the cause of the failure is a cause other than the fuel pump, the replacement of the fuel pump assembly occurs, the expensive repair cost is generated, there is a problem that causes consumer complaints.

The present invention has been invented to solve the above problems, the purpose of which is to cause the self-diagnosis of the fuel pump in the vehicle to be applied to the Elpia system for various reasons such as short circuit or disconnection of the signal line, failure of the driver, failure of the fuel pump By self-diagnosing and outputting a diagnostic code accordingly, it is to provide convenience and reliability of maintenance.

The present invention for realizing the above object is an interface unit for interfacing the driving information detected by the various sensors mounted on the vehicle; A control unit for determining and controlling a fuel injection amount suitable for a current driving condition according to the driving information detected through the interface unit, calculating a driving speed of the fuel pump based on the driving information, and outputting a PWM control signal; A motor driver for driving the fuel pump according to the PWM control signal applied from the controller; A switching unit configured of a plurality of semiconductor power devices, the switching unit driving the fuel pump by converting a DC voltage into a three-phase voltage by switching according to a PWM signal applied from a motor driver; A first reference value setting unit for setting a table for each phase reference PWM signal for driving a fuel pump according to a fuel injection amount condition; A first comparator for feedback detection of each phase PWM control signal output from the motor driver to the switching unit, and then comparing with the reference PWM signal set in the first reference value setting unit and outputting a result thereof; A second reference value setting unit for setting a reference value for a driving speed of the fuel pump according to a condition of the fuel injection amount in a table; A second comparator for comparing a driving speed of a fuel pump with a reference speed value set in the second reference value setting unit and outputting a result thereof; And an abnormality detector for analyzing the signals applied from the first and second comparators to perform self-diagnosis for short circuits, disconnection of the signal lines, and failure of the fuel pump, and to provide a result thereof to the controller. Fuel pump and driver diagnosis device of Elpia

In addition, the step of detecting the operation information in the state of starting the fuel injection amount and the driving speed of the fuel pump; Outputting a PWM control signal according to the driving speed of the fuel pump to drive the fuel pump; Monitoring the motor driver controlling the driving of the fuel pump and performing self-diagnosis; Detecting a PWM control signal output by the motor driver for driving the fuel pump and performing self-diagnosis of the short circuit or disconnection of the signal line by comparing with the first reference value set;

Detecting a driving speed of the fuel pump and comparing the preset second reference value with a self-diagnosis of the failure of the fuel pump; It provides a fuel pump and driver diagnostic method for an Elpia vehicle comprising the step of outputting the result of the self-diagnosis as a diagnostic code.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The fuel pump and driver diagnosis apparatus for an Elpia vehicle according to the present invention includes an interface unit 10, a control unit 20, a motor driver 30, a switching unit 40, a first reference value setting unit 50, and a first unit. The comparator 60, the second reference value setting unit 70, the second comparator 80, and the abnormality detection unit 90 are configured to be included.

The interface unit 10 controls operation information detected by various sensors (not shown), such as intake air amount, opening of the throttle valve, temperature and pressure of the fuel supply line, intake air temperature, cooling water temperature, and the like. And self-diagnostic information related to the fuel pump M determined by the control unit 20 to be output to the display means not shown so that the code of the self-diagnosis can be displayed.

The control unit 20 analyzes and matches the driving information detected through the interface unit 10 through a set algorithm to determine and control the fuel injection amount suitable for the current operating conditions, and to determine the fuel injection amount to be injected into the combustion chamber. The driving speed of the pump M is calculated and applied to the motor driver 30 as a PWM signal.

In addition, by monitoring the operation of the motor driver 30, it is determined whether the motor driver 30 is abnormal, and outputs a self-diagnosis code thereof to the interface unit 10, the short circuit or disconnection of the fuel pump (M) or the signal line, etc. The self-diagnosis code is output to the interface unit 10 according to the diagnosis result.

The switching unit 40 is composed of a plurality of semiconductor power devices, preferably a plurality of FET devices (FET1-FET6), and is switched according to the PWM signal applied to the gate terminal of the motor driver 30 so as to provide a DC supply voltage (V). _BATT ) is converted to three-phase [(U +, U-), (V +, V-), (W +, W-)] voltages and applied to the fuel pump M as a phase voltage to the fuel pump motor M. Allow drive to take place.

The first reference value setting unit 50 is a table of each phase reference PWM signal for driving the fuel pump (M) in accordance with the respective fuel injection amount conditions, the table of the reference PWM signal is an optimal value determined through repetitive learning to be.

The first comparator 60 feedback-detects each phase PWM signal outputted by the motor driver 30 to switch the plurality of FET devices FET1-FET6 in the switching unit 40, and then the first reference value setting unit ( Compare with the reference PWM signal set in 50) and outputs the result.

The second reference value setting unit 70 sets a reference value for the driving speed of the fuel pump M according to the condition of each fuel injection amount as a table, and the reference speed value is an optimal value determined through repetitive learning.

The second comparator 80 compares the driving speed of the fuel pump M with a reference speed value set in the second reference value setting unit 70 and outputs a result thereof.

The abnormality detection unit 90 analyzes signals applied from the first comparator 60 and the second comparator 80 and performs self-diagnosis for short circuits, disconnection of the signal line, and failure of the fuel pump M. The result is provided to the control unit 20.

If the information applied from the first comparator 60 is abnormal, the abnormality detection unit 90 determines that a normal PWM signal is not output due to a short circuit or a disconnection of the signal line outputting the PWM control signal.

In addition, the abnormality detection unit 90 determines that a failure that the fuel pump (M) is not normally driven when the information applied from the second comparator 80 is abnormal.

That is, when the driving speed of the fuel pump (M) is included in the range of the set reference value, for example, 30% of the reference value, it is determined that the driving of the fuel pump (M) is normally performed, and outputs a self-diagnosis code thereof. If it exceeds the range of the set reference value, it is determined that the fuel pump (M) is a failure and outputs a self-diagnosis code for it.

The operation of the present invention including the above functions will be described with reference to FIG. 2 as follows.

In the state in which the engine of the vehicle to which the Elpia system is applied is maintained at start-up (S101), various sensors connected to the interface unit 10 are driven from the intake manifold through the driving information under current conditions, for example, a MAP sensor. The amount of intake air flowing into the combustion chamber, the opening of the throttle valve linked to the operation of the accelerator pedal, the pressure and temperature of the fuel supply line, the intake temperature, the cooling water temperature, and the like are detected and applied to the controller 20 (S102).

Therefore, the controller 20 analyzes the detected driving information through a set algorithm to determine the fuel injection amount, and determines the speed of the fuel pump M according to the determined fuel injection amount (S103) to control the PWM in the motor driver 30. The signal is output (S104).

The motor driver 30 controls the driving of the fuel pump M with a three-phase voltage by switching a plurality of FET elements FET1-FET6 in the switching unit 40 according to the PWM control signal applied from the control unit 20. (S105).

In the state of controlling the driving of the fuel pump M as described above, the controller 20 monitors the state of the motor scriber 30 (S106), and determines whether normal operation is being performed (S107).

If the operation of the motor driver 30 is not normal in the determination of step S107, it is determined that there is a fault in the internal circuit (S108), and outputs a set self-diagnosis code, preferably a signal of 10 Hz, to the interface unit 10. Through the display means not shown through the display (S109).

However, when it is determined in S107 that the motor driver 30 is operating normally, the first comparator 60 monitors the driving signal for feedback detection of each phase PWM control signal output to the motor driver 30. (S110).

Thereafter, the monitored driving signal is compared with a reference value according to a current fuel injection amount condition set as a table in the first reference value setting unit 50, and the result thereof is output to the abnormality detection unit 90 (S111).

In addition, the second comparator 80 detects the speed of the fuel pump M by feedback (S112), and determines the speed of the fuel pump M according to the current fuel injection amount condition set in the second reference value setting unit 70. The result of comparison with the reference value is output to the abnormality detector 90 (S113).

At this time, the abnormality detection unit 90 analyzes the signal applied from the first comparator 60 to determine whether the control signal for driving the fuel pump M is normally output (S114), the second comparator 80 By analyzing the applied signal, it is determined whether the fuel pump M is driven within a normal speed, that is, within 30% of the set reference value (S115).

If it is determined in S114 that the driving control signal of the fuel pump M output from the motor driver 30 is in an abnormal state, it is determined that a short circuit or disconnection of the signal line is generated, and the diagnostic information about the control unit 20 is determined. It is applied to (S116).

Accordingly, the control unit 20 outputs a self-diagnosis code for a short circuit or disconnection of the signal line, preferably a signal of 20 Hz, to the fuel pump M driving signal line to display means not shown through the interface unit 10. It indicates the information that a disconnection or short circuit has occurred (S117).

As a result of the determination in S114, the driving control signal of the fuel pump M output from the motor driver 30 is determined to be in a normal state, and as a result of the determination in S115, the fuel pump M is in a range of a normal speed, that is, a set reference value. If it is determined that the operation within%, it is determined that it is operating normally (S118), and the diagnostic information about it is applied to the control unit 20 (S118).

Therefore, the control unit 20 outputs a self-diagnosis code, preferably 5 Hz, signal indicating that the fuel pump M is operating normally, and instructs the display means (not shown) through the interface unit 10 (S119). ).

However, if it is determined in S115 that the fuel pump M is operating at an abnormal speed, that is, out of 30% of the set reference value, it is determined that the fuel pump M is malfunctioning and the diagnostic information is determined. 20) (S120).

Therefore, the control unit 20 outputs a self-diagnosis code for the failure of the fuel pump M, preferably a signal of 15 Hz, to be displayed on the display unit (not shown) through the interface unit 10 (S121).

As described above, according to the present invention, in diagnosing a failure of a fuel pump in a vehicle to which an Elpia system is applied, the present invention diagnoses an error of a fuel pump by diagnosing abnormalities of peripheral parts and lines related to the operation of the fuel pump. This prevents this from happening and provides reliability and stability in maintenance based on self-diagnosis information.

Claims (16)

In the vehicle fuel pump self-diagnosis device of Elpia, An interface unit to interface driving information detected by various sensors mounted on the vehicle; A control unit for determining and controlling a fuel injection amount suitable for a current driving condition according to the driving information detected through the interface unit, calculating a driving speed of the fuel pump based on the driving information, and outputting a PWM control signal; A motor driver for driving the fuel pump according to the PWM control signal applied from the controller; A switching unit configured of a plurality of semiconductor power devices, the switching unit driving the fuel pump by converting a DC voltage into a three-phase voltage by switching according to a PWM signal applied from a motor driver; A first reference value setting unit for setting a table for each phase reference PWM signal for driving a fuel pump according to a fuel injection amount condition; A first comparator for feedback detection of each phase PWM control signal output from the motor driver to the switching unit, and then comparing with the reference PWM signal set in the first reference value setting unit and outputting a result thereof; A second reference value setting unit for setting a reference value for a driving speed of the fuel pump according to a condition of the fuel injection amount in a table; A second comparator for comparing a driving speed of a fuel pump with a reference speed value set in the second reference value setting unit and outputting a result thereof; An abnormality detector for analyzing the signals applied from the first and second comparators and performing self-diagnosis on short circuits, disconnections, and failures of the fuel pumps and providing the results thereof to the controller; Fuel pump and driver diagnostic apparatus for an Elpia vehicle comprising a. The method of claim 1, And the interface unit outputs self-diagnostic information related to the fuel pump determined by the control unit to the display unit so that the code of the self-diagnosis can be displayed. The method of claim 1, The control unit monitors the operation of the motor driver and outputs a self-diagnosis code for an abnormality to the interface unit, and transmits a self-diagnosis code for a short circuit / disconnection of a fuel pump or a signal line according to the diagnostic information applied from the abnormality detecting unit. Fuel pump and driver diagnostic apparatus for an Elpia vehicle, characterized in that the output. The method of claim 1, The switching unit comprises a plurality of FET device fuel pump and driver diagnostic apparatus for an Elpia vehicle. The method of claim 1, And the abnormality detector detects a short circuit or a disconnection of the signal line outputting the PWM control signal when the information applied from the first comparator is abnormal. The method of claim 1, The abnormality detecting unit of the fuel pump and driver diagnostic apparatus of the Elpia vehicle, characterized in that it determines that the failure of the fuel pump when information applied from the second comparator is abnormal. The method of claim 1, The second comparator determines that the fuel pump is normal when the driving speed of the fuel pump is within the range of the set reference value (30%), and judges that the fuel pump is faulty only if the fuel pump is out of the range of the set reference value. Fuel pump and driver diagnosis device for child car. The method of claim 1, The control unit is a fuel pump and driver diagnostic apparatus for an Elpia vehicle, characterized in that for outputting a 20Hz signal for the short circuit or disconnection of the signal line. The method of claim 1, The control unit is a fuel pump and driver diagnostic apparatus for an Elpia vehicle, characterized in that for outputting a 10Hz signal for the failure of the motor driver as a self-diagnosis code. The method of claim 1, The control unit is a fuel pump and driver diagnostic device for an Elpia vehicle, characterized in that for outputting a 15Hz signal for the failure of the fuel pump as a self-diagnosis code. The method of claim 1, The control unit is a fuel pump and driver diagnostic apparatus for an Elpia vehicle, characterized in that for outputting a signal of 5Hz for the steady state with a self-diagnosis code. Detecting fuel injection amount and driving speed of the fuel pump by detecting operation information in the state of starting-up; Outputting a PWM control signal according to the driving speed of the fuel pump to drive the fuel pump; Monitoring the motor driver controlling the driving of the fuel pump and performing self-diagnosis; Detecting a PWM control signal output by the motor driver for driving the fuel pump and performing self-diagnosis of the short circuit or disconnection of the signal line by comparing with the first reference value set; Detecting a driving speed of the fuel pump and comparing the preset second reference value with a self-diagnosis of the failure of the fuel pump; Outputting the result of the self-diagnosis as a diagnostic code; Fuel pump and driver diagnostic method of the vehicle is an Elpia comprising a. The method of claim 12, If the failure of the motor driver is determined, the fuel pump and driver diagnostic method for an Elpia vehicle, characterized in that to output a self-diagnosis code with a signal of 10Hz. The method of claim 12, And a self-diagnosis code is output as a signal of 20 Hz when it is determined that the signal line for transmitting the PWM control signal is shorted or disconnected. The method of claim 12, If the failure of the fuel pump is determined, the fuel pump and driver diagnostic method for an Elpia vehicle, characterized in that to output a self-diagnosis code with a signal of 15Hz. The method of claim 12, If a failure is not detected in the fuel pump system, the fuel pump and driver diagnostic method for an Elpia vehicle, characterized in that to output a self-diagnosis code with a signal of 5Hz.

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