AU2006201763B2

AU2006201763B2 - System for Preventing Fuel Leakage for LPI Injector

Info

Publication number: AU2006201763B2
Application number: AU2006201763A
Authority: AU
Inventors: Jeong Nam Park
Original assignee: Hyundai Motor Co
Current assignee: Hyundai Motor Co
Priority date: 2005-08-30
Filing date: 2006-04-27
Publication date: 2007-12-13
Anticipated expiration: 2026-04-27
Also published as: ITMI20060793A1; JP2007064197A; CN100420844C; CN1924339A; KR100656022B1; NL1031660C2; AU2006201763A1; NL1031660A1

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 Jeong Nam Park HODGKINSON McINNES PAPPAS Patent Trade Mark Attorneys Levels 3, 20 Alfred Street MILSONS POINT NSW 2061 "System for Preventing Fuel Leakage for LPI Injector" Details of Basic Application: Korea Patent Application No. 10-2005-0080013 Filed 30 August 2005 The following statement is a full description of this invention, including the best method of performing it known to us: P20486AU00 SYSTEM FOR PREVENTING FUEL LEAKAGE FOR LPI INJECTOR CROSS REFERENCE TO RELATED APPLICATION This application claims priority to and the benefit of Korean Patent Application No. 10-2005-0080013 filed in the Korean Intellectual Property Office on August 30, 2005, the entire content of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a system for preventing fuel from being leaked through a nozzle tip of an injector via a cut solenoid valve when an engine is stopped in LPI vehicles, and more particularly to a system for preventing fuel leakage for an LPI injector, in which in a state where the cut solenoid valve is shut off when the engine is stopped, LPG gas filled in a gas holding section inside the cut solenoid valve is discharged to the outside to be collected, so that the LPG gas is prevented from being leaked through a nozzle tip of the injector.

Description of the Related Art In general, an LPG engine is equipped with a system in which fuel supplied from a bombe, an LPG tank is vaporized via a mixer and a vaporizer to be supplied to the engine.

However, such a system employing the mixer and the vaporizer embraces the following several problems. Precise control of the system by ECU is difficult, and hence starting is difficult in wintertime. Also, power performance and fuel consumption ratio level is low as well as there occur idle instability and the abrupt stopping of the engine starting due to a failure in a consumer's observance of maintenance period instructions, which is caused by problems associated with tar contained in the LPG fuel.

There has proposed an LPI engine to address and solve the above problems.

Typically, the Liquefied Petroleum Injection (LPI) engine refers to an engine system in which a fuel pump is installed inside an LPG bombe so that liquid-phase LPG fuel is pumped from the LPG bombe to be delivered under pressure to a carburetor for vaporization via a fuel supply line, and then the high-pressure LPG fuel vaporized in the carburetor is injected into the engine through an injector, dissimilarly to an existing LPG engine adapted to push out fuel by using only vapor pressure.

That is, the LPI engine adopts an injection method in which the LPG fuel is directly injected into a combustion chamber of the engine through an injector nozzle like gasoline vehicles. For such an LPI engine, the LPG fuel is supplied to the combustion chamber through the injector under the precise control of the ECU without using a mixer and a vaporizer, so that fuel consumption ratio and power performance and startability in wintertime are improved, as well as chronic problems associated with old LPG vehicles such as unsatisfaction for maintenance period, etc., are completely resolved.

In the meantime, FIG. 1 is a cross-sectional view illustrating the structure of a conventional injector applied to an LPI engine according to the prior art.

Referring to FIG. 1, at an inside lower portion of an injector 10 is mounted a cut solenoid valve 13 for preventing LPG gas from being leaked when an engine is stopped.

The cut solenoid valve 13 serves to interrupt the introduction of the LPG gas into a combustion chamber through an intake manifold and a surge tank when the engine is stopped so that a large amount of exhaust gas can be prevented from being discharged at the time of re-starting of the engine, thereby coping with the present Ultra Low Emission Vehicle (ULEV) regulation or a higher-level regulation.

In FIG. 1, reference numeral 11 denotes a fuel supply port for charging fuel into the injector 10 therethrough, and reference numeral 12 represents a nozzle tip for injecting the fuel into the engine therethrough.

The cut solenoid valve 13 includes a plunger valve member 14 for opening and closing a fuel passageway inside the injector 10, and a solenoid for operating the plunger valve member 14 when being applied with electric power.

However, as mentioned above, the cut solenoid valve 13 functions to interrupt the leakage of the LPG fuel from the nozzle tip 12 of the injector into the combustion chamber at the time of stopping of the engine. However, actually in the case where the engine is stopped after the starting of the engine, the temperature of the injector and cut solenoid valve portion sharply rises so that the pressure inside of the cut solenoid valve also rises. Resultantly, it is difficult to maintain air tightness at the seat portion of the cut solenoid valve, which leads to a leakage of gas from the nozzle tip 12 of the injector 10 into the combustion chamber of the engine.

Such gas leakage deteriorates the startability of the engine and contributes to an increase in exhaust gases.] In addition, high electric force is required and the size of the solenoid must be increased in order to operate the cut solenoid valve, which results in an inconvenience of installation.

Table 1 below shows an increase in pressure at the cut solenoid valve portion of the injector at the time of stopping of the engine.

[Table 1] During the Driving (just before starting Starting off (at MAX pressure of injector cut off) solenoid valve) Fuel Pressure Temp. of Fuel Pressure Temp. of Time after pressure in cut ICING tip pressure in cut ICING tip starting off (kg/cm') solenoid (kg/cm') solenoid (sec) valve valve (kg/cm') _(kg/c) Regulator orifice 11.03 0 79 7.057 7.283 90 92.2 (00.2) Regulator orifice 10.28 0 80.9 10.445 10.668 96.9 368.7 (free) SUMMARY OF THE INVENTION Accordingly, the present invention has been made to address and solve the aforementioned problems occurring in the prior art, and it is an object of the present invention to provide a system for preventing fuel leakage for an LPI injector, in which in a state where the cut solenoid valve is shut off when the engine is stopped, LPG gas filled in a gas holding section inside the cut solenoid valve is discharged to the outside to be collected, so that the LPG gas is prevented from being leaked through a nozzle tip of the injector.

To accomplish the above object, according to the present invention, there is provided a system for preventing fuel leakage for an LPI injector, including: an exhaust nipple extendably connected to a gas holding section where LPG gas is hold inside a cut solenoid valve at a state where the cut solenoid valve is shut off inside an injector, in such a fashion as to communicate with the outside; a cut-off solenoid valve installed at the other end of an exhaust hose connected at one end to a distal end of the exhaust nipple and adapted to open/close the exhaust hose under the control of an electric control unit (ECU); and collection means connected to a rear portion of the cut-off solenoid valve via a hose and adapted to adsorb and store the LPG gas which passes through the cut-off solenoid valve and is discharged from the cut-off solenoid valve.

Preferably, the electric control unit may control the cut-off solenoid valve to be closed during the operation of an engine and to be opened during the starting off of the engine.

Also, preferably, the collection means may include a canister which has activated carbons contained therein and is formed at one side with an air discharge port and formed at the other side with a purge side outlet connected to a purge control solenoid valve for inducing the gas adsorbed and stored in the canister into an intake system under the control of the electric control unit when being opened during the operation of the engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view illustrating the structure of a conventional injector applied to an LPI engine according to the prior art.

FIG. 2 is a schematic diagrammatic view illustrating the construction of a system for preventing fuel leakage for an LPI injector according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT Reference will now be made in detail to the preferred embodiment of the present invention with reference to the attached drawings.

The present invention is directed to a system for preventing fuel from being leaked through a nozzle tip of an injector via a cut solenoid valve when an engine is stopped in LPI vehicles, and more particularly to such a system for preventing fuel leakage for an LPI injector, in which in a state where the cut solenoid valve is shut off'when the engine is stopped, LPG gas filled in a gas holding section inside the cut solenoid valve is discharged to the outside to be collected, so that the LPG gas is prevented from being leaked through a nozzle tip of the injector.

The preferred embodiment of the present invention will now be described in detail hereinafter with reference to FIG. 2.

First, at a state where a cut solenoid valve 13 is shut off inside an injector 10, an exhaust nipple 21 communicating with the outside is extendably connected to a gas holding section 16 inside the cut solenoid valve 13 where LPG gas is hold. At this time, to a distal end of the exhaust nipple is connected one end of an exhaust hose 22.

A separate cut-off solenoid valve 23 is installed at the other end of the exhaust hose 22, and collection means 24 is connected to a rear portion of the cut-off solenoid valve 23 via a hose.

The cut-off solenoid valve 23 is adapted to be opened/closed so as to open/close the exhaust hose 22 in response to a signal applied thereto from an electric control unit (ECU) The collection means 24 is adapted to adsorb and store the fuel which passes through the cut-off solenoid valve 23 and is discharged from the cut-off solenoid valve. The collection means 24 is not limited to a canister having any certain structure, but a canister, which can contemporarily store a certain amount of fuel and supply it to an intake system, is sufficient for the collection means. A known HC trap is taken as an example of the collection.

In the meantime, the canister 24 is formed at one side with an air discharge port 25 similarly to a typical canister, and formed at the other side with a purge side outlet 24 connected to a purge control solenoid valve (hereinafter, referred to as "PCSV") 28 via a hose 27.

Further, the PCSV 28 is connected to an intake system of the engine, a surge tank so as to induce the gas adsorbed and stored in the canister 24 into the intake system when being opened.

Herein, the PSCV 28 is adapted to be opened/closed in response to a signal applied thereto from the electric control unit (ECU) Now, the operation of the present invention will be described in detail hereinafter.

First, the cut-off solenoid valve 23 is closed during the operation of the engine, and is opened at the time of stopping of the engine under the control of the electric control unit At this time, the electric control unit 30 generates a control signal to close the cut-off solenoid valve 23 during the starting-on of the engine, i.e., when the engine is started and a control signal to open the cut-off solenoid valve 23 during the starting-off of the engine, when the engine is stopped.

That is, the cut-off solenoid valve 23 is closed/opened according to the startingon/off state of the engine under the control of the electric control unit In this manner, when the cut-off solenoid valve 23 is opened at the time of stopping of the engine, the LPG gas is discharged to the cut-off solenoid valve through the exhaust nipple 21 of the injector 10 and is introduced into the canister 24, which in turn adsorbs the LPG gas on the surfaces of activated carbon particles contained therein to store it therein, and then discharge air to the air through an air discharge port In addition, when the cut-off solenoid valve 23 is shut off at the time of starting of the engine, the electric control unit 30 controls the PSCV 29 to be opened so as to induce the gas stored in the canister 24 to an intake system, a surge tank together with external air under suction negative pressure.

As described above, according to the inventive fuel leakage-preventing system for an LPI injector, at the time of stopping of the engine, LPG gas leaked from the gas holding section of the cut solenoid valve inside the injector through the exhaust nipple is contemporarily adsorbed and stored in the collection means, and then is induced to the intake system of the engine at the time of operating the engine. As a result, the LPG gas is prevented from being leaked from the gas holding section of the cut solenoid valve through the nozzle tip of the injector.

As apparent from the foregoing, the inventive fuel leakage-preventing system for an LPI injector has an advantageous effect in that LPG gas leaked from the gas holding section of the cut solenoid valve of the injector through the exhaust nipple at the time of stopping of the engine is contemporarily adsorbed and stored in the collection means, and then is induced to the intake system of the engine at the time of operating the engine, so that the LPG gas can be prevented from being leaked from the gas holding section of the cut solenoid valve through the nozzle tip of the injector as well as emission of the exhaust gas can be minimized at the early time of the starting of the engine.

Furthermore, since the present invention makes it possible to automatically reduce the pressure in the gas holding section of the cut solenoid valve inside the injector, it can completely resolve the conventional problems in that the size of the solenoid must be increased in order to operate the cut solenoid valve.

While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.

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

1. A system for preventing fuel leakage for an LPI injector, comprising: an exhaust nipple extendably connected to a gas holding section of the injector where LPG gas is hold inside a cut solenoid valve at a state where the cut solenoid valve is shut off inside the injector, in such a fashion as to communicate with the outside; a cut-off solenoid valve installed at the other end of an exhaust hose connected at one end to a distal end of the exhaust nipple and adapted to open/close the exhaust hose under the control of an electric control unit (ECU); and collection means connected to a rear portion of the cut-off solenoid valve via a hose and adapted to adsorb and store the LPG gas which passes through the cut-off solenoid valve and is discharged from the cut-off solenoid valve.

2. The system set forth in claim 1, wherein the electric control unit controls the cut-off solenoid valve to be closed during the operation of an engine and to be opened during the starting off of the engine.

3. The system set forth in claim 1, wherein the collection means comprises a canister which has activated carbons contained therein and is formed at one side with an air discharge port and formed at the other side with a purge side outlet connected to a purge control solenoid valve for inducing the gas adsorbed and stored in the canister into an intake system under the control of the electric control unit when being opened during the operation of the engine.

4. A system for preventing fuel leakage for an LPI injector as substantially hereinbefore described and with reference to the accompanying Figures. Dated this 2 7 t h day of January 2006. Hvundai Motor Comoanv HODGKINSON MclNNES PAPPAS Patent Attorneys for the Applicant