AU703827B2

AU703827B2 - Liquefied petroleum gas injection apparatus

Info

Publication number: AU703827B2
Application number: AU40991/96A
Authority: AU
Inventors: Bill Ross Campbell
Original assignee: GAS INJECTION TECHNOLOGIES Pty
Current assignee: GAS INJECTION TECHNOLOGIES Pty Ltd
Priority date: 1995-01-13
Filing date: 1996-01-15
Publication date: 1999-04-01
Anticipated expiration: 2016-01-15
Also published as: AU4099196A

Description

OBJECT OF TIHE INVENTION It is therefore an object of the invention to provide an improved system for the fuel injection of an alternate fuel (such as LPG) into an internal combustion engine.

DISCLOSURE OF THE INVENTION According to one aspect of the invention there is disclosed a fuel injection system for an internal combustion engine, said system having a first fuel line connected to a first set of injector valves for injecting a first fuel into an inlet manifold of said engine, a second fuel line connected to a second set of injector valves for injecting a second fuel into said inlet ~manifold, a control apparatus being electrically connected to both said first and second set of valves providing a signal for determining injector valve timing for both said first and second set of valves dependent on the operation of said engine when using either said first fuel or said second fuel, wherein said second set injector valves are capable of operating at pressures at 70-100 kPa above manifold pressure.

Preferably the first fuel is liquid petroleum fuel whilst the second fuel is liquefied petroleum gas (LPG) fuel.

In another preferable form, the system includes in the second fuel line a fuel rail to supply the second fuel to the second set of injector valves. The system also includes a pressurised fuel tank with shut off valve means, a pressure reduction device and pressure regulator means, which controls the pressure of the second fuel to be proportional to the manifold vacuum pressure.

In another preferable form, the system includes a heat exchange means in the second fuel line to heat the second fuel as it expands in the pressure reduction device and therefore a supply of heat is desirable for more efficient combustion. In one preferable form the heat exchange means is associated with the pressure reduction device and transfers heat from the engine's coolant to the second fuel. The coolant is preferably ducted through pipes to the pressure reduction device.

In another preferred form, the heat exchange means comprises an air/gas heat exchanger compressor/evaporator located in the air inlet of the manifold. This provides heat transfer to the second fuel as well as transferring heat from the intake air which assists with the combustion efficiency of the second fuel/air mixture.

In a further preferred form, the heat exchange means comprises the evaporator located in the air conditioning unit of the motor vehicle, if there is an air conditioning unit installed.

In another form of the invention, there is disclosed an injector adaptor for use on an internal combustion engine having a duel fuel injection system using a first fuel and a second fuel, said system including a first set of at least one fuel injector valve(s) and a second set of at 10 least one fuel injector valve(s) for feeding corresponding said first and second fuels to an a._ inlet manifold in said engine, said adaptor having first and second inlet ports and an outlet port, said adaptor being fitted to said engine with said outlet port connected to said inlet manifold to said engine, said first inlet port receiving the outlet port of one of said first set of "injector valve(s) which is fitted thereto and said second inlet port communicating with the outlet port of one of said set of second injector valve(s), wherein there is only one set of apertures in said inlet manifold of said engine for the two sets of said fuel injector valve(s).

*Preferably, the first inlet port and the outlet port of the adaptor are aligned along the longitudinal axis of the adaptor with the second inlet port being located along the longitudinal side thereof BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the present invention will now be described with reference to the drawings in which; Fig. 1 is a schematic diagram of an LPG injection unit of a first embodiment; Fig. 2 is a schematic diagram of an LPG injection unit of a second embodiment; Fig. 3 is a schematic diagram of the installation of an LPG injector adaptor apparatus of a preferred embodiment; and Fig. 4 is a detailed transverse cross-sectional view of the LPG injector adaptor apparatus of Fig. 3.

BEST MODE OF CARRYING OUT THE INVENTION One embodiment of a fuel injection system 10 for a motor vehicle (not illustrated) is shown in Fig. 1. The fuel injection system 10 is used to supply two different fuels to the engine (not illustrated) of the motor vehicle with one of the fuels being liquid petroleum (or petrol) and the other fuel being LPG. It is noted again that this embodiment is also suitable when 10 using fuels other than the aforementioned fuels. The system 10 include a conventional fuel S. injection system used for petrol, this conventional system has not been illustrated fully as the components are well known. The conventional petrol fuel injection system includes a petrol fuel line 11 which connects to a petrol rail 12 to which conventional petrol injectors 13 are connected. The petrol injectors 13 are operated by control signals (not illustrated) supplied from an Electronic Engine Management or EEM 14 which travel via leads 15 to electrically operated solenoid valves 16 of the injectors 13 in the conventional manner.

The system 10 also includes an LPG fuel injection apparatus 17 which includes an LPG tank 18 with a shut off valve 19. An LPG fuel line 20 is connected to the shut off valve 19 and a further shut off valve/filter 19a is connected into the LPG fuel line 20 for safety reasons.

The preferred pressure within the LPG tank 18 and adjacent section 20a of fuel line 20 is 700-750 kPa. A primary pressure regulator/heat exchanger 21 is positioned within the fuel line 20 and is used to reduce the LPG pressure to a preferable pressure of about 210 kPa in the next section 20b of the fuel line 20. The primary regulator/heat exchanger 21 requires a heat source to provide the energy for the decrease in the pressure which has associated gas expansion. In this embodiment the heat source is the heat contained in the engine's coolant which passes through pipes 22 to and from the regulator/heat exchanger 21.

A control regulator 23 is located downstream of the primary regulator/heat exchanger 21 in the fuel line 20. The control regulator 23 which has a vacuum line connected thereto, is used to control the LPG pressure to be proportional to the manifold vacuum. In the preferred operation, the LPG pressure in section 20c of fuel line 20 is approximately 70-100 kPa above manifold pressure.

The section 20c of the fuel line 20 is connected to an LPG fuel rail 24 to which injector valves 25 are connected. The LPG fuel rail 24 assists in the even spread of the LPG. The LPG injector valves 25 are operated by control signals supplied by the EEM 14 according to the timing requirements of the valves 25 due to the type of fuel being used. A change over relay 26 is used to change the signal to the appropriate leads 15 depending on the mode of operation of the engine. Solenoids 29 operate the valves ooooo 10 In this embodiment the petrol injectors 13 are fitted to adaptors 27 which are fitted to the fuel inlet of the engine. The LPG injector valves 25 have an extra fuel line 28 which connects between the outlet of the LPG injector valves 25 and the adaptors 27. This ensures that both fuels are fed at the same location and less conversion is required. It is noted that this is only a preferred arrangement and the fuel feed locations can vary according to 15 performance requirements. This embodiment described above has the advantage that the system 10 is simplified compared with known arrangements. The use of the LPG injector valves 25 require operation which has not heretobefore been available. The LPG injector valves 25 are rated to perform injection of LPG at required pressures.

In another embodiment as illustrated in Fig. 2, The components are the same as described above except that the primary regulator/heat exchanger 21 of the above described embodiment is replaced by a pressure regulator 31 which has its output connected to either an air/gas heat exchanger unit 32 located in the air inlet of the air intake manifold, or to an air conditioning unit evaporator 33 (if one is installed in the motor vehicle). The line 20 has a diverter valve 34 which opens and closes sections 20d and 20e of the fuel line 20. A shuttle valve 35 connects these sections back into the fuel line The embodiment as described above has the advantages that the system 10 (Fig. 2) utilises the existing equipment of the motor vehicle to assist in better performance of the engine when operating in the LPG injection mode, or can provide better performance by the addition of extra components, as it has been found that the air flow into the air intake manifold can be reduced by up to 100 C which can improve performance of the engine.

It is noted that even though the embodiment illustrated in Fig. 2, shows either heat exchanger 32 or air conditioning unit evaporator 33, it is within the scope of the invention that either one or both these units can also be installed in any combination with the primary heat exchanger 21 as described in respect of the embodiment illustrated in Fig. 1.

In another form of the invention, the adaptors 27 are illustrated in greater detail in Figs. 3 and 4. The adaptors 27 each have a generally tubular body 37 with a first inlet port 38 and an outlet port 39 aligned with the longitudinal axis of the body 37. The first inlet port 38 is shaped to receive the outlet port 40 of a petrol injector 13, as illustrated in Fig. 3. The outlet port 39 is shaped identically to the outlet port 40 of the petrol injector 13 so that it can be received in a fuel inlet 41 of the inlet manifold 42 of the engine. The adaptors 27 also have a second inlet port 43 which is connected by the extra fuel line 28 to the outlet (not illustrated) of the LPG injector valve 25. The second inlet port 43 connects to the side of 15 the tubular body 37.

The adaptors 27 enable the system 10 to be implemented without the need for extra apertures to be made in the manifold 42 and ensures efficient operation as the LPG is injected at the optimum position, and the injector valves 25 can be positioned at the most advantageous position and not necessarily fitted to the inlet manifold 42 of the engine.

The foregoing describes only some embodiments of the present invention and modifications obvious to those skilled in the art can be made thereto without departing from the scope of the present invention.

The claims defining the invention are as follows: 1. A fuel injection system for an internal combustion engine, said system having a first fuel line connected to a first set of injector valves for injecting a first fuel into an inlet manifold of said engine, a second fuel line connected to a second set of injector valves for injecting a second fuel into said inlet manifold, a control apparatus being electrically connected to both said first and second set of valves providing a signal for determining injector valve timing for both said first and second set of valves dependent on the operation of said engine when using either said first fuel or said second fuel, wherein said second set injector valves are capable of operating at pressures at 70-100 kPa above manifold pressure.

@oo 10 2. A fuel injection system as claimed in claim 1, the system further includes in the second o" fuel line a fuel rail to supply the second fuel to the second set of injector valves, a 0*go •pressurised fuel tank with shut off valve means, a pressure reduction device and pressure •regulator means, which controls the pressure of the second fuel to be proportional to the C..o manifold vacuum pressure.

3. A fuel injection system as claimed in claim 1 or 2, wherein the system further includes a heat exchange means in the second fuel line.

4. A fuel injection system as claimed in claim 3, wherein the heat exchange means •comprising an air/gas heat exchanger compressor/evaporator located in the inlet manifold which provides heat transfer to the second fuel as well as transferring heat from intake air 20 which assists with the combustion efficiency of the second fuel/air mixture.

A fuel injection system as claimed in claim 3, wherein the heat exchange means comprises the evaporator located in the air conditioning unit of the motor vehicle, if there is an air conditioning unit installed.

6. A fuel injection system as claimed in any one of the preceding claims, further including an injector adaptor having first and second inlet ports and an outlet port, said adaptor being fitted to said engine with said outlet port connected to said inlet manifold to said engine, said first inlet port receiving the outlet port of one of said first set of injector valves which

Claims

7. A fuel injection system as claimed in claim 6, wherein the first inlet port and the outlet port of the adaptor are aligned along longitudinal axis of the adaptor with the second inlet port being located along the longitudinal side thereof.
8. A fuel injection system as claimed in any one of the preceding claims, wherein the first fuel is liquid petroleum fuel whilst the second fuel is liquefied petroleum gas (LPG) fuel. oII °e DATED this FIFTH day of FEBRUARY 1999 10 GAS INJECTION TECHNOLOGIES PTY LIMITED Patent Attorneys for the Applicant WILSON YOUNG S us S SS S AE hsFIT a fFERAY19 ABSTRACT LIQUEFIED PETROLEUM GAS INJECTION APPARATUS A fuel injection system (10) for an internal combustion engine is disclosed. The system has a first fuel line (11) connected to a first set of injector valves (13) for injecting a first fuel into an inlet manifold (42) of the engine and a second fuel line (20) connected to a second set of injector valves (25) for injecting a second fuel into the intake manifold A control apparatus (14) is electrically connected to both the first and second set of valves (13, 25) for determining injector valve timing for both said first and second set of valves (13, dependent on the type of fuel and required operation of the engine when using either the first fuel or the second fuel, wherein the second set of injector valves (25) are capable of operating at pressures greater than conventional fuel injector valves (13). Fig. 2 oo o*