AU2006201752A1 - Diagnosing System and Method of LPI Engine - Google Patents

Diagnosing System and Method of LPI Engine Download PDF

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Publication number
AU2006201752A1
AU2006201752A1 AU2006201752A AU2006201752A AU2006201752A1 AU 2006201752 A1 AU2006201752 A1 AU 2006201752A1 AU 2006201752 A AU2006201752 A AU 2006201752A AU 2006201752 A AU2006201752 A AU 2006201752A AU 2006201752 A1 AU2006201752 A1 AU 2006201752A1
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Prior art keywords
fuel pump
cut
valve
relay
malfunction
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AU2006201752A
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AU2006201752B2 (en
Inventor
Deok Ryol Kim
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Hyundai Motor Co
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Hyundai Motor Co
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3082—Control of electrical fuel pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/021—Control of components of the fuel supply system
    • F02D19/022—Control of components of the fuel supply system to adjust the fuel pressure, temperature or composition
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/021—Control of components of the fuel supply system
    • F02D19/023—Control of components of the fuel supply system to adjust the fuel mass or volume flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/025—Failure diagnosis or prevention; Safety measures; Testing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D19/02—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with gaseous fuels
    • F02D19/026—Measuring or estimating parameters related to the fuel supply system
    • F02D19/027—Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/32—Controlling fuel injection of the low pressure type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0203—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels characterised by the type of gaseous fuel
    • F02M21/0209—Hydrocarbon fuels, e.g. methane or acetylene
    • F02M21/0212—Hydrocarbon fuels, e.g. methane or acetylene comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M21/00—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form
    • F02M21/02—Apparatus for supplying engines with non-liquid fuels, e.g. gaseous fuels stored in liquid form for gaseous fuels
    • F02M21/0218—Details on the gaseous fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
    • F02M21/0245—High pressure fuel supply systems; Rails; Pumps; Arrangement of valves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Description

AUSTRALIA
Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT
ORIGINAL
Name of Applicant: Actual Inventor: Address for Service: Invention Title: Hyundai Motor Company Deok Ryol Kim HODGKINSON McINNES PAPPAS Patent Trade Mark Attorneys Levels 3, 20 Alfred Street MILSONS POINT NSW 2061 "Diagnosing System and Method of LPI Engine" Details of Basic Application: Korea Patent Application No. 10-2006-0034611 Filed 17 April 2006 The following statement is a full description of this invention, including the best method of performing it known to us: P20500AU00 TITLE OF THE INVENTION DIAGNOSING SYSTEM AND METHOD OF LPI ENGINE CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2006-0034611 filed in the Korean Intellectual Property Office on April 17, 2006, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a diagnosing system and method of a liquefied petroleum injection (LPI) engine. More particularly, the present invention relates to a diagnosing system and a diagnosing method of an LPI engine having advantages of promptly diagnosing a malfunction of a fuel pump relay by constantly monitoring an output voltage of the fuel pump relay.
Description of the Related Art Generally, an LPI engine refers to an engine where a fuel pump is mounted in a bombe and an LPG fuel is injected to the engine through an injector by supplying the LPG fuel to the injector in a liquid state. The LPI engine may meet emission regulations, and may solve various problems of a conventional LPG system such as bad starting in winter and deterioration of output power.
As shown in FIG. 4, an LPI system includes a bombe 1 having a fuel pump 2 for supplying a liquefied fuel to an engine E, a fuel supply line 4 having one end connected to the fuel pump 2 and the other end connected to an injector 7 of the engine E, a fuel return line 8 having one end connected to the bombe 1 and the other end connected to the engine E.
Therefore, the fuel supplied from the fuel pump 2 is carried successively through the fuel supply line 4 and an injector 7 and injected to a combustion chamber. Then, a remaining fuel is returned to the bombe 1 through the fuel return line 8.
The fuel supply line 4 is provided with a first cut-off valve 3 and a second cut-off valve 5 for cutting off a fuel supply when the engine E stops, and a temperature sensor 6 for detecting a fuel temperature.
The fuel return line 8 is provided with a pressure sensor 9 for detecting a fuel pressure and a pressure regulator 10 for maintaining the fuel pressure within a predetermined range.
In addition, the LPI system is provided with an engine control unit (ECU) 11 for controlling an operation of the engine E and an LPI electronic control unit (ECU) 12 for controlling the fuel supply.
A method of controlling the engine E according to the conventional LPI system is described as follows.
If an ignition switch is turned on, the ECU 11 controls the LPI ECU 12 to turn on a main relay (not-shown) and a fuel pump relay (not-shown) so as to input a battery power to the fuel pump 2.
Accordingly, the fuel pump 2 is operated and supplies a liquefied fuel from the bombe 1 to the fuel supply line 4.
The LPI ECU 12 opens the first cut-off valve 3 and the second cut-off valve 5 so that the liquefied fuel is supplied to the injector 7.
After that, if the ECU 11 detects that the ignition switch is turned off, the ECU 11 controls the LPI ECU 12 to turn off the main relay and the fuel pump relay. In addition, the LPI ECU 12 closes the first cut-off valve 3 and the second cut-off valve 5 so that the fuel is not supplied to the engine E.
According to the conventional LPI system, in a case that the fuel pump relay malfunctions, the power is not supplied to the fuel pump 2, the first cut-off valve 3, and the second cut-off valve Therefore, in a case that the fuel pump relay is in a state of a simple malfunction, the operation of the fuel pump 2 is stopped and simultaneously the first cut-off valve 3 and the second cut-off valve 5 are closed. Therefore, the fuel supply to the engine E is completely cut off and the engine E is stopped.
Therefore, disastrous accidents may occur if the above situation occurs in a running state of a vehicle.
In addition, in cases that the fuel pump relay is in a state of a simple malfunction, it is impossible for a driver to restart the engine since the fuel supply is completely cut off.
Therefore, the vehicle has to be towed in order to receive maintenance.
In addition, since no malfunction code is stored in spite of the simple malfunction of the fuel pump relay, all starting parts must be checked in order to find a cause of the malfunction.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a diagnosing system and a diagnosing method of an LPI engine having advantages of constantly monitoring an output voltage of a fuel pump relay and determining whether the fuel pump relay malfunctions in order to promote convenient and prompt maintenance.
In addition, the present invention has advantages of supporting safe running by preventing the engine from stopping if the fuel pump relay malfunctions in a running state of a vehicle.
An exemplary diagnosing system of an LPI engine according to an embodiment of the present invention includes: a bombe having a fuel pump driver for controlling an operation of a fuel pump and a first cut-off valve for cutting off a fuel supply to the engine; a pressure regulator having a pressure sensor for detecting a fuel pressure and a second cut-off valve for cutting off the fuel supply to the engine; a relay unit having a fuel pump relay and a main relay; an LPG switch for cutting off the fuel supply to the engine in an emergency; and an LPI ECU electrically connected to the fuel pump driver, the first cut-off valve, the second cut-off valve, the relay unit, and the LPG switch, and controlling an operation thereof, wherein the LPI ECU has a malfunction-diagnosing unit for diagnosing a malfunction of the fuel pump relay.
The malfunction-diagnosing unit may identify the malfunction of the fuel pump relay in cases where an output voltage of the fuel pump relay is smaller than or equal to a predetermined reference voltage.
The predetermined reference voltage may be Meanwhile, the malfunction-diagnosing unit identifies the malfunction of the fuel pump relay in cases where all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction.
An exemplary diagnosing method of an LPI engine according to an embodiment of the present invention includes: determining whether an ignition switch of the engine is turned on; turning on a main relay and a fuel pump relay if the ignition switch is determined to be turned on; operating a fuel pump and opening a first cut-off valve and a second cut-off valve; determining whether an LPG switch is turned on; comparing an output voltage of the fuel pump relay with a predetermined reference voltage if the LPG switch is determined to be turned on; and identifying a malfunction of the fuel pump relay and storing a malfunction code if the output voltage of the fuel pump relay is smaller than or equal to the predetermined reference voltage.
If the LPG switch is determined to be turned off, the exemplary diagnosing method further includes: turning off the fuel pump; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
If the output voltage of the fuel pump relay is greater than the predetermined reference voltage, the exemplary diagnosing method further includes: determining whether the ignition switch is turned off; turning off the main relay and the fuel pump relay if the ignition switch is turned off; and stopping the operation of the fuel pump and closing the first and second cut-off valves.
The predetermined reference voltage may be An exemplary diagnosing method of an LPI engine according to a second embodiment of the present invention includes: determining whether an ignition switch of the engine is turned on; turning on a main relay and a fuel pump relay if the ignition switch is determined to be turned on; operating a fuel pump and opening a first cut-off valve and a second cut-off valve; determining whether an LPG switch is turned on; determining whether all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction if the LPG switch is determined to be turned on; and identifying a malfunction of the fuel pump relay and storing a malfunction code if all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction.
If the LPG switch is determined to be turned off, the second exemplary diagnosing method further includes: turning off the fuel pump relay; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
If any one of the fuel pump, the first cut-off valve, and the second cut-off valve does not malfunction, the second exemplary diagnosing method further includes: determining whether the ignition switch is turned off; turning off the main relay and the fuel pump relay if the ignition switch is determined to be turned off; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a diagnosing system of an LPI engine according to an exemplary embodiment of the present invention.
FIG. 2 is a flowchart showing a diagnosing method of an LPI engine according to another exemplary embodiment of the present invention.
FIG. 3 is a flowchart showing a diagnosing method of an LPI engine according to a further exemplary embodiment of the present invention.
FIG. 4 is a schematic diagram of a conventional LPI engine.
DETAILED DESCRIPTION OF THE EMBODIMENTS Hereinafter, referring to figure 1, an exemplary diagnosing system of an LPI engine according to an embodiment of the present invention will be described in detail.
FIG. 1 is a schematic diagram of a diagnosing system of an LPI engine according to an exemplary embodiment of the present invention.
As shown in FIG. 1, an exemplary diagnosing system of an LPI engine according to an embodiment of the present invention includes a bombe 400, a pressure regulator 500, a relay unit 300, an LPG switch 200, and an LPI electronic control unit (ECU) 100.
The bombe 400 stores a fuel in a liquid state. The bombe 400 is provided with a fuel pump driver 405 for controlling an operation of a fuel pump (not shown) in the bombe 400 and a first cut-off valve 401 for cutting off fuel supply to the engine.
The pressure regulator 500 maintains a fuel pressure within a predetermined range so that the fuel is not leaked to a cylinder through an injector. The pressure regulator 500 is provided with a pressure sensor 503 for detecting the fuel pressure and a second cut-off valve 501 for cutting off the fuel supply to the engine.
The relay unit 300 is provided with a main relay 310 for supplying a power to a plurality of sensors and a fuel pump relay 320 for controlling an operation of the fuel pump driver 405.
The LPG switch 200 cuts off the fuel supply to the engine in an emergency according to a driver's control.
The LPI ECU 100 includes a cut-off valve control portion 120, an LPG switch controller 110, a fuel pump relay control portion 101, and a malfunction-diagnosing unit 103.
The cut-off valve control portion 120 includes a first driver 121, a first switching element 123, a second driver 125, and a second switching element 126.
The first driver 121 is connected to the first cut-off valve 401 and controls an operation of the first cut-off valve 401. The first switching element 123 is operated according to a control signal of the first driver 121.
The second driver 125 is connected to the second cut-off valve 501 and controls an operation of the second cut-off valve 501. The second switching element 126 is operated according to a control signal of the second driver 125.
The LPG switch controller 110 includes a switch driver 111 and a switching element 113. The LPG switch controller 110 is connected to the LPG switch 200 and controls an operation of the LPG switch 200. The switch driver 111 operates the switching element 113 according to a control signal input from an engine control unit (not shown).
In addition, an output portion of the LPG switch 200 is electrically connected to the LPI ECU 100 so that the LPI ECU 100 monitors an operation of the LPG switch 200.
The fuel pump relay control portion 101 controls the fuel pump relay 320 according to the control signal input from the engine control unit (not shown).
The malfunction-diagnosing unit 103 is connected to an output portion of the fuel pump relay 320 and constantly monitors an output voltage of the fuel pump relay 320. If the output voltage of the fuel pump relay 320 is smaller than or equal to a predetermined voltage, the malfunction-diagnosing unit 103 identifies a malfunction of the fuel pump relay 320 or its electrical wiring. Then, a malfunction code is output and stored in the LPI ECU 100.
In addition, the malfunction-diagnosing unit 103 monitors an operation of the fuel pump driver 405 included in the bombe 400 and determines whether the fuel pump driver 405 malfunctions. In addition, the malfunction-diagnosing unit 103 constantly monitors an operation of the first cut-off valve 401 included in the bombe 400 and the second cut-off valve 501 included in the pressure regulator 500. The malfunction-diagnosing unit 103 determines whether the first cut-off valve 401 and the second cut-off valve 501 malfunction.
Hereinafter, referring to figure 2, an exemplary diagnosing method of an LPI engine according to another embodiment of the present invention will be described in detail.
FIG. 2 is a flowchart showing a diagnosing method of an LPI engine according to another exemplary embodiment of the present invention.
As shown in FIG. 2, the LPI ECU 100 determines whether an ignition switch is turned on at step S101, in a communication with the engine control unit
(ECU).
If the ignition switch is determined to be turned off, an LPI system remains un-activated. If the ignition switch is determined to be turned on, the main relay 310 is turned on and the fuel pump relay control portion 101 turns on the fuel pump relay 320 at step S102.
When the fuel pump relay 320 is turned on, a power input to the fuel pump relay 320 is supplied to a fuel pump. Therefore, the fuel pump is operated at step S103.
In addition, the cut-off valve control portion 120 opens the first and second cut-off valves 401 and 501 so that a liquefied fuel fed with pressure by an operation of the fuel pump is supplied to the injector at step S104.
After that, while the liquefied fuel is supplied to the injector, the LPI ECU 100 determines whether the LPG switch 200 is turned on at step S105.
If the LPG switch 200 is determined to be turned off, the LPI ECU 100 identifies that a driver intends to urgently cut off the fuel supply to the engine at step S106. In this case, the LPI ECU 100 tums off the fuel pump relay 320 at step S107. In addition, the LPI ECU 100 stops the operation of the fuel pump and closes the first and second cut-off valves 401 and 501 so as to cut off the fuel supply to the engine at step S108.
If the LPG switch 200 is determined to be turned on at the step S 105, an output voltage of the fuel pump relay 320 is detected at step S109 and is compared with the predetermined reference voltage at step S110.
If the output voltage of the fuel pump relay 320 is smaller than or equal to the predetermined reference voltage, the LPI EUC 100 identifies a malfunction of the fuel pump relay 320 or its electrical wiring at step S115, and stores a malfunction code at step S116.
If the output voltage of the fuel pump relay 320 is greater than the predetermined reference voltage at the step S 110, the LPI ECU 100 determines at step S111 whether the ignition switch is turned off.
If the ignition switch is determined to be turned off, the main relay 310 and the fuel pump relay 320 are turned off at step S112 and the fuel pump is stopped at step S113.
In addition, the first and second cut-off valves 401 and 501 are closed at step S114 so as to cut off the fuel supply to the engine.
Meanwhile, the predetermined reference voltage may be Referring to FIG. 3, another exemplary diagnosing method of an LPI engine according to a further embodiment of the present invention will be described in detail.
FIG. 3 is a flowchart showing a diagnosing method of an LPI engine according to the further exemplary embodiment of the present invention.
As shown in FIG. 3, the LPI ECU 100 is interlocked to the engine control unit and determines whether the ignition switch is turned on at step S101.
If the ignition switch is determined to be turned off, the LPI system remains un-activated. If the ignition switch is determined to be turned on, the main relay 310 is turned on and the fuel pump relay control portion 101 turns on the fuel pump relay 320 at step S102.
When the fuel pump relay 320 is turned on, a power input to the fuel pump relay 320 is supplied to the fuel pump. Therefore, the fuel pump operates at step S103.
In addition, the cut-off valve control portion 120 opens the first cut-off valve 401 and the second cut-off valve 501 so that the liquefied fuel fed with pressure by an operation of the fuel pump is supplied to the injector at step S104.
After that, in a state that the liquefied fuel is supplied to the injector, the LPI ECU 100 determines whether the LPG switch 200 is turned on at step S105.
If the LPG switch 200 is turned off, the LPI ECU 100 identifies that a driver intends to urgently cut off the fuel supply to the engine at step S106. In this case, the LPI ECU 100 turns off the fuel pump relay 320 at step S107. In addition, the LPI ECU 100 stops the operation of the fuel pump and closes the first and second cut-off valves 401 and 501 so as to cut off the fuel supply to the engine at step $108.
If the LPG switch 200 is determined to be turned on at the step S105, the LPI ECU 100 determines at step S110' whether all of the fuel pump, the first cut-off valve 401, and the second cut-off valve 501 malfunction.
If all of the fuel pump, the first cut-off valve 401, and the second cut-off valve 501 are determined to malfunction, the LPI EUC 100 identifies a malfunction of the fuel pump relay 320 or its electrical wiring at step S115 and stores a malfunction code at step S116.
If any one of the fuel pump, the first cut-off valve 401, and the second cut-off valve 501 does not malfunction at the step S110', the LPI ECU 100 determines whether the ignition switch is turned off at step S111.
If the ignition switch is determined to be turned off, the main relay 310 and the fuel pump relay 320 are turned off at step S112 and the fuel pump is stopped at step S113.
In addition, the first cut-off valve 401 and the second cut-off valve 501 are closed so as to cut off the fuel supply to the engine at step S114.
While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
As described above, the present invention identifies a malfunction of a fuel pump relay and its electrical wiring and stores a malfunction code in an LPI ECU. Therefore, convenient maintenance is possible according to the present invention.
In addition, in a case that a fuel pump relay is in a state of simple malfunction, an engine is maintained to operate such that a vehicle moves to an inspection station under a predetermined condition.
The term "comprising" (and its grammatical variations) as used herein is used in the inclusive sense of "having" or "including" and not in the exclusive sense of "consisting only of'.

Claims (13)

1. A diagnosing system of an LPI engine, comprising: a bombe having a fuel pump driver for controlling an operation of a fuel pump and a first cut-off valve for cutting off a fuel supply to the engine; a pressure regulator having a pressure sensor for detecting a fuel pressure and a second cut-off valve for cutting off the fuel supply to the engine; a relay unit having a fuel pump relay and a main relay; an LPG switch for cutting off the fuel supply to the engine in an emergency; and an LPI ECU electrically connected to the fuel pump driver, the first cut-off valve, the second cut-off valve, the relay unit, and the LPG switch and controlling an operation thereof, wherein the LPI ECU has a malfunction-diagnosing unit for diagnosing a malfunction of the fuel pump relay.
2. The diagnosing system of claim 1, wherein the malfunction-diagnosing unit identifies the malfunction of the fuel pump relay in cases where an output voltage of the fuel pump relay is smaller than or equal to a predetermined reference voltage.
3. The diagnosing system of claim 2, wherein the predetermined reference voltage is
4. The diagnosing system of claim 1, wherein the malfunction-diagnosing unit identifies the malfunction of the fuel pump relay in cases where all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction.
A diagnosing method of an LPI engine, comprising: determining whether an ignition switch of the engine is turned on; turning on a main relay and a fuel pump relay if the ignition switch is determined to be turned on; operating a fuel pump and opening a first cut-off valve and a second cut-off valve; determining whether an LPG switch is turned on; comparing an output voltage of the fuel pump relay with a predetermined reference voltage if the LPG switch is determined to be turned on; and identifying a malfunction of the fuel pump relay and storing a malfunction code if the output voltage of the fuel pump relay is smaller than or equal to the predetermined reference voltage.
6. The diagnosing method of claim 5, further comprising: turning off the fuel pump relay if the LPG switch is determined to be turned off; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
7. The diagnosing method of claim 5, further comprising: determining whether the ignition switch is turned off if the output voltage of the fuel pump relay is greater than the predetermined reference voltage; turning off the main relay and the fuel pump relay if the ignition switch is determined to be turned off; and stopping the operation of the fuel pump and closing the first and second cut-off valves.
8. The diagnosing method of claim 5, wherein the predetermined reference voltage is
9. A diagnosing method of an LPI engine, comprising: determining whether an ignition switch of the engine is tumrned on; turning on a main relay and a fuel pump relay if the ignition switch is determined to be turned on; operating a fuel pump and opening a first cut-off valve and a second cut-off valve; determining whether an LPG switch is turned on; determining whether all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction if the LPG switch is determined to be turned on; and identifying a malfunction of the fuel pump relay and storing a malfunction code if all of the fuel pump, the first cut-off valve, and the second cut-off valve malfunction.
The diagnosing method of claim 9, further comprising: turning off the fuel pump relay if the LPG switch is determined to be turned off; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
11. The diagnosing method of claim 9, further comprising: determining whether the ignition switch is turned off if any one of the fuel pump, the first cut-off valve, and the second cut-off valve does not malfunction; turning off the main relay and the fuel pump relay if the ignition switch is determined to be turned off; and stopping an operation of the fuel pump and closing the first and second cut-off valves.
12. A diagnosing system of an LPI engine as substantially hereinbefore described and with reference to Figures 1-3.
13. A diagnosing method of an LPI engine as substantially hereinbefore described and with reference to Figures 1-3. Dated this 2 7 t h day of April 2006. Hyundai Motor Company HODGKINSON MclNNES PAPPAS Patent Attorneys for the Applicant
AU2006201752A 2006-04-17 2006-04-27 Diagnosing System and Method of LPI Engine Ceased AU2006201752B2 (en)

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ITMI20060839A1 (en) 2007-10-18
NL1031709C2 (en) 2009-01-20
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CN100520018C (en) 2009-07-29
AU2006201752B2 (en) 2009-03-05

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