KR20090012937A - Method for changing fuel of bi fuel car - Google Patents

Abstract

An injector malfunction information processing method of a bi-fuel vehicle is provided to automatically convert the fuel and then restrict the fuel conversion in the current operation cycle when the specific injector malfunctions and confirm the normality of the injector by temporarily allowing the fuel conversion in the next operation cycle. An injector malfunction information processing method of a bi-fuel vehicle comprises the steps of: initializing the fuel conversion restriction flag by injector malfunction into zero after starting(103); maintaining a counter at the previously stored value when the corresponding injector malfunction diagnostic flag is zero, while setting the counter to half the set counter critical value when the corresponding injector malfunction diagnostic flag is one(105); diagnosing fault of the corresponding injector in the set cycle when the corresponding injector is driven and increasing or decreasing the counter(109,111,113); and setting the injector malfunction diagnostic flag to zero when the counter reaches zero, while setting the injector malfunction diagnostic flag to one when the counter reaches the counter critical value(117,119,121,123).

Description

How to handle injector failure information for fuel switching in bi-fuel vehicles {METHOD FOR CHANGING FUEL OF BI FUEL CAR}

The present invention relates to a method for switching fuel when diagnosing an injector failure of a bifuel vehicle, and more particularly, when a failure of a specific injector is diagnosed in a bifuel vehicle which drives an engine by combining gasoline fuel and CN fuel. It relates to a method of limiting, or allowing the use of.

In general, the fuel used in Bi-Fuel vehicles uses gasoline or gas, and gasoline and compressed natural gas (CNG) or gasoline and liquefied petroleum gas are used to complement each other's advantages and disadvantages. LPG (Liquid Platum Gas) is used in combination.

Such a bi-fuel vehicle receives a gasoline injection signal supplied from a gasoline engine control unit to generate a gas injection signal at the interface box, and supplies gas fuel (LPG or CNG) in the fuel tank to the gas injector according to the gas injection signal. It is provided.

One of the prior arts for such a bifuel vehicle is to switch to the normal fuel system when an abnormality is found in one fuel system, which usually involves a failure of the injector. For example, a combined gasoline and CNENG vehicle is automatically converted to CNENG when a gasoline injector failure is diagnosed. In contrast, the CNENG injector is automatically converted to gasoline. In addition, when the driver asks the fuel to be switched while driving with gasoline, if the CNENG injector fails, it does not allow the fuel to be switched for the safety of the system, and vice versa when the gasoline injector fails.

These functions are classified as essential for safety, but there is one problem with the injector diagnosis. Diagnosis of failure of the injector, that is, electrical short circuit, disconnection or short circuit, is performed only when the injector is opened. Therefore, in order to determine that the injector that has failed once is normal, the corresponding injector must be driven. However, the above function prevents the injector from running in any case by prohibiting the conversion to the fuel if there is an injector that is determined to be defective. Electrical short circuits or short circuits of the injector are often observed automatically after appearing intermittently due to deterioration of electric wires, rainwater, etc., and thus, the above functions have many limitations.

The present invention has been made to solve the above problems, and an object of the present invention is to separate the 'injector failure' flag and the 'fuel limiting fuel injection by the injector failure' flag operating according to the fault diagnosis result of the injector, and to diagnose the counter. By adjusting the value of on the basis of the start-on, it is possible to switch the fuel in each operation to recheck whether the injector is normal and to accurately determine the latest state of the injector.

Injector failure information processing method for fuel switching of a bi-fuel vehicle according to an aspect of the present invention for achieving the above object,

An injector failure information processing method for fuel conversion of a bi-fuel vehicle which drives an engine by supplying gasoline fuel and CN fuel to each gas injector and gasoline injector using a gasoline engine control unit and an interface box,

a) initializing the fuel conversion limit flag due to injector failure to '0' after starting on;

b) It is determined whether the pre-stored injector fault diagnosis flag indicating the fault diagnosis result of the injector is set to '1', and if the corresponding injector fault diagnosis flag is '0', the counter is kept at the previously stored value. Setting the counter to half of a preset counter threshold value if '1';

c) when the injector is driven, executing fault diagnosis of the injector at predetermined preset periods and increasing or decreasing the counter; And

d) When the counter reaches '0' as a result of step c), the injector failure diagnosis flag is set to '0', and when the threshold is reached, the fuel change limit flag due to injector failure is set to '1'. Characterized in that it comprises a step.

Step c)

c-1) executing a failure diagnosis of the corresponding injector every predetermined period;

c-2) decreasing the counter when the injector is normal as a result of the fault diagnosis of the corresponding injector of step c-1), and increasing the counter when a failure occurs;

Step d)

d-1) comparing the counter threshold calculated in step c-2 with the counter threshold value,

d-2) When the value of the counter is a counter threshold as a result of the determination in step d-1), the 'injector failure diagnosis' flag and the 'fuel switching limit due to the injector failure' flag are set to '1', If the value is '0', set the 'Injector Failure Diagnosis' flag and 'Injector Failure Fuel Restriction' flag to '0'.

In the present invention, when the 'fuel limiting fuel injection due to injector failure' flag is '1', the fuel conversion is prohibited, and when '0', the fuel conversion is possible.

As described above, according to the present invention, the automatic switching of the fuel occurs at the first time when the failure of the specific injector is determined and the switching of the fuel is prohibited in the operation cycle. The effect is to recheck whether the injector has returned to normal.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the exemplary embodiment of the present invention, a bifuel vehicle using both CNG and gasoline fuel, which are compressed natural gas fuels, will be described as an example.

FIG. 1 is a diagram illustrating a configuration of a bi-fuel vehicle that drives an engine by combining gasoline and CN fuel of the present invention, and FIG. 2 is a detailed view of a fuel conversion process through the gasoline engine control unit 70 shown in FIG. 1. This is a flow chart for explaining.

As shown in FIG. 1, the internal combustion engine for CNG fuel of a bi-fuel vehicle according to the present invention includes a fuel tank 1 for storing CNG (Compressed Natural Gas) fuel under a pressurized state, and a fuel. The CNG fuel stored in the tank 1 flows in, and the pressure regulator 30 reduces and discharges the pressure of the CNG fuel introduced below a predetermined threshold value, and the fuel discharged from the pressure regulator 30 flows in. Distributor for supplying each of the CNG fuels quantitatively controlled, for example, 5-10 solenoids, to the intake manifold of the engine 3 by quantitative control according to the load state of the engine 3. 40, a gas injector (nozzle) 50 for injecting the fuel quantitatively controlled and distributed by the plurality of solenoids of the fuel distributor 40 into the combustion chamber of the engine intake manifold, and the gasoline engine control unit 70 Cans from Engine speed (RPM), throttle position sensor (TPS), ignition time information, manifold absolute pressure (MAP), coolant temperature, fuel temperature in the pressure regulator 30, oxygen signal and fuel distributor 40 And an interface box 60 for driving control of the plurality of solenoids of the fuel distributor 40 based on the pressure signals at at least two positions of the "

In addition, since the internal combustion engine related to gasoline fuel in the bi-fuel vehicle according to the present invention is already known, a detailed description thereof will be omitted.

In addition, the interface box 60 is provided to receive the injection signal generated in the gasoline engine control unit 70 in accordance with the engine state information through the injection line is converted to gasoline or gas injection signal.

At this time, the pressure of the compressed CN fuel in the fuel tank 1 is about 200 to 250 bar, and the pressure is reduced by the pressure regulator 30 below a predetermined threshold value (about 2 to 10 bar), so that it is supplied to the engine. The injection pressure of the CNG fuel is approximately 2-10 bar.

The interface box 60 further includes a counter for counting the number of failures of the injector, and in addition, the injector failure diagnosis threshold is preset and stored. The injector failure counter threshold is a result obtained through a number of experiments to optimally control the engine.

In other words, the interface box 60 sets the injector failure diagnosis flag and the fuel switching limit flag. Here, the injector fault diagnosis flag is stored as data showing a fault diagnosis result of the injector, and the fuel change limit flag is data for limiting the conversion of the fuel used to the corresponding fuel supplied to the failing injector. Is stored. That is, if the injector failure diagnosis flag of the interface box 60 is '1', the injector is determined to be a failure, and if it is '0', the injector is determined to be normal.

In addition, the interface box 60 limits the switching to the corresponding fuel when the fuel change restriction flag is '1', and allows the switching to the corresponding fuel when the fuel change limit flag is '0'. Determined to be.

That is, the interface box 60 initializes a counter that counts the number of occurrences of the corresponding injector failure signal after the start-up, and determines whether the pre-stored injector failure diagnosis flag is set to '1' indicating that the injector failure has occurred. If the injector failure diagnosis flag is '1', the value of the counter is set to half of the preset threshold.

Subsequently, the interface box 60 executes a fault diagnosis of the injector every predetermined period while the injector is driven, and counts the counter according to a fault diagnosis result of the injector executed every predetermined period. The value is compared with a preset counting threshold.

As a result of the comparison, when the counting value is equal to or greater than the counting threshold value, the corresponding injector failure warning light is turned on, and then the injector failure diagnosis flag is set to '1', and the fuel change limit flag is set to '1', respectively. do.

The fuel conversion process of the bifuel vehicle through the gasoline engine control unit 70 will be described in more detail with reference to FIG. 2.

First, the interface box 60 first initializes the counter (103) after starting on (103), determines whether the stored injector failure diagnosis flag is' 1 '(105), and the injector failure diagnosis flag is' 1 ', the counter is set to half of the pre-stored injector failure diagnosis threshold (107). In addition, when the injector failure diagnosis flag is '0', the counter is maintained at a previously stored value. (108).

Thereafter, the interface box 60 executes the fault diagnosis of the injector every predetermined period while the injector is driven (109), and determines whether the injector failure has occurred as a result of the corresponding injector failure diagnosis performed every predetermined cycle (111). After the failure of the injector occurs, the counter is counted (113).

The increased counting value of the step 113 is compared with the counting threshold set in the step 107 (115), and if the counting value is greater than the counting threshold value as a result of the comparison, the injector failure warning light turns on after the injector failure warning light is turned on. The diagnostic flag is set as the first data (117), and the fuel change limit flag is set as the first data (119).

Thereafter, the gasoline engine control unit 70 determines whether the engine is turned off (120), and if not started, proceeds to the step 109, and if the engine is turned off, the program ends.

On the other hand, when the counting value is less than the counting threshold value through the step 115, the injector failure warning light is turned off, the injector failure diagnosis flag is set as the second data (121), and the corresponding fuel change limit flag is set to the second. After setting with data (123), the process proceeds to step 120.

In addition, if a failure of the corresponding injector does not occur through the step 111, the counting value of the counter is decreased (125) and the process proceeds to the step 115.

Therefore, as an example, rainwater was injected into the injector connector while driving to CNG, and the injector was diagnosed as a failure, and the automatic conversion to gasoline was performed immediately. After that, the gasoline pump failed when the injector returned to normal. In this case, if the engine switching is prohibited due to the failure of the CNENG injector and the engine is turned off, steering and braking will not function properly, which will cause adverse effects in various aspects, including safety. It is reasonable to keep.

As such, those skilled in the art to which the present invention pertains will understand that the present invention may be embodied in other specific forms without changing to the technical spirit or essential features of the present invention. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. .

1 is a schematic view showing the configuration of a bi-fuel vehicle according to the present invention.

2 is a flowchart illustrating a fuel conversion process according to the present invention.

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

1: fuel tank 3: engine

30: pressure regulator 40: fuel distributor

50: gas injector 60: interface box

70: gasoline engine control unit

Claims (3)

A bi-fuel vehicle which drives an engine by supplying gasoline fuel and CN fuel to each gas injector and gasoline injector using a gasoline engine control unit and an interface box, a) initializing the fuel conversion limit flag due to injector failure to '0' after starting on; b) It is determined whether the pre-stored injector fault diagnosis flag indicating the fault diagnosis result of the injector is set to '1', and if the corresponding injector fault diagnosis flag is '0', the counter is kept at the previously stored value. Setting the counter to half of a preset counter threshold value if '1'; c) when the injector is driven, executing fault diagnosis of the injector at predetermined preset periods and increasing or decreasing the counter; And d) When the counter reaches '0' as a result of step c), the injector failure diagnosis flag is set to '0', and when the threshold is reached, the fuel change limit flag due to injector failure is set to '1'. Injector failure information processing method for the fuel conversion of the bi-fuel vehicle, characterized in that it comprises a. The method of claim 1, wherein c) c-1) executing a failure diagnosis of the corresponding injector every predetermined period; c-2) reducing the counter when the corresponding injector is normal as a result of the fault diagnosis of the corresponding injector of step c-1), and increasing the counter when the failure occurs. Method of processing injector failure information. The method of claim 2, wherein d) d-1) comparing the counter threshold calculated in step c-2 with the counter threshold value, d-2) When the value of the counter is a counter threshold as a result of the determination in step d-1), the 'injector failure diagnosis' flag and the 'fuel switching limit due to the injector failure' flag are set to '1', If the value is '0', the injector failure information processing method for the fuel conversion of the fuel vehicle, characterized in that the 'injector failure diagnosis' flag and the 'fuel conversion limit by the injector failure' flag is set to '0'.

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