WO2000004288A1

WO2000004288A1 - A fuel vaporisation system

Info

Publication number: WO2000004288A1
Application number: PCT/AU1999/000577
Authority: WO
Inventors: Timothy Wyse
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-07-17
Filing date: 1999-07-16
Publication date: 2000-01-27
Anticipated expiration: 2001-01-17
Also published as: GB2358437B; AU4764399A; GB2358437A; AU741692B2; GB0103231D0; HK1039168B; HK1039168A1; DE19983386T1

Abstract

The present invention relates generally to a fuel vaporisation system (10) comprising a fuel vaporisation adaptor (12), heating means in the form of an electrical heating element (14), a digital controller (16), and a temperature sensor (19). The vaporisation system (10) is designed to retrofit to a fuel system of a conventional internal conbustion engine. The vaporisation adaptor (12) is plumbed or conveniently retrofits with a fuel rail (26) and an intake manifold (24) of the combustion engine. The adaptor (12) is die-cast in stainless steel and comprises a conical-shaped body portion (28) which defines an inlet bore (30) formed continuous with an outlet spigot (32) defining an outlet passageway (34). The inlet bore (30) is shaped generally complementary to the fuel injector (15) which is retractably located within the inlet bore (30). The vaporisation adaptor (12) is fitted to an inlet manifold (13).

Description

A FUEL VAPORISATION SYSTEM

FIELD OF THE INVENTION

The present invention relates generally to a fuel vaporisation system and relates particularly, though not exclusively, to a fuel vaporisation adaptor suitable for retrofitting to a conventional internal combustion engine.

BACKGROUND TO THE INVENTION It is widely recognised that internal combustion engines of motor vehicles are major contributors to greenhouse gas emissions. These emissions include CO, C0₂, SOX, and NOX gases together with unburnt fuel. Improving the combustion efficiency of the engine together with optimisation of the fuel to air ratio significantly reduces greenhouse gas emissions. Electronically fuel injected (EFI) engines as compared to carburetted engines provide improved combustion efficiency wherein the injection of fuel and exhaust of emissions is electronically controlled to accurately coincide with the engines cycle. However, particularly under "cold start" conditions, unburnt fuel is still prevalent at relatively high levels exceeding that which can be scrubbed by a catalytic converter. This problem has previously been addressed by incorporating a liquid fuel vaporisation system upstream of the combustion chamber.

The vaporisation system such as that disclosed in US Patent No. 4,452,215 is used in conjunction with a conventional fuel carburettor and regulated via analogue control.

UK patent No. 2263501 describes a fuel injector fitted to a cup of a fuel vaporiser which is mounted to an intake manifold. The fuel vaporiser includes a heating element which is formed of a porous ceramic body having a cavity into which a jet of fuel from the fuel injector is directed. The ceramic heating element is set in the cup of the fuel vaporiser. Fuel is driven through the ceramic body into the manifold as a result of the increased vapour pressure in the cavity.

SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a fuel vaporisation adaptor designed to retrofit to an intake manifold of an internal combustion engine, said adaptor comprising: a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore; and a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector, the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway.

According to another aspect of the present invention there is provided a fuel vaporisation system designed to retrofit to an internal combustion engine, said system comprising: a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore; a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector, the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway; and a digital controller operatively coupled to the heating element whereby in operation vaporisation of the fuel is controlled by the digital controller depending on the temperature and/or pressure of the fuel. Preferably the inlet bore is shaped generally complementary to at least a portion of the fuel injector which thus fits within the inlet bore. More preferably the adaptor includes one or more annular seals disposed between the injector and the body portion of the adaptor.

Typically the adaptor also includes an insulating housing located within the outlet passageway and surrounding the heating element. More typically the insulating housing is a cylindrical-shaped housing formed of a ceramic material such as an alumina ceramic.

Generally the heating element is an elongate wire formed as a helix having its axis coaxial with that of the outlet passageway. In one embodiment the wire helix is formed of nichrome wire.

Preferably the heating element is a variable resistance heating element. More preferably the variable resistance heating element is capable of heating the fuel to between 210 to 260°C to achieve in excess of 90% vaporisation.

Typically the adaptor further includes a temperature sensor connected to the body portion immediately downstream of the heating element. More typically the temperature sensor is a thermocouple element.

Typically, the digital controller includes one or more circuit boards being configured to activate the heating element dependent on temperature and/or pressure signals received from temperature and/or pressure sensors. In one embodiment the vaporisation system includes an interface between the digital controller and an electronic fuel injection (EFI) system, the interface being designed to adjust the EFI system to correct for vaporisation of the fuel. Alternatively, the vaporisation system includes a converter board operatively coupled to the EFI system so as to adjust the system, and in particular pulse signals for activating injector valves, to correct for vaporisation of the fuel.

According to a further aspect of the present invention there is provided a method of improving fuel combustion efficiency in a combustion engine, said method comprising the steps of: providing a fuel vaporisation adaptor including a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore, and a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector; and retrofitting said vaporisation adaptor to an intake manifold of the combustion engine with the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway.

Generally retrofitting of the vaporisation adaptor involves additionally spacing the fuel rail from the intake manifold to accommodate the adaptor. Additionally, if the existing injectors are not disposed parallel to each other, a new fuel rail is included in the installation.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to achieve a better understanding of the nature of the present invention a preferred embodiment of a fuel vaporisation adaptor and fuel vaporisation system will now be described in some detail, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a schematic flow diagram of a fuel vaporisation system included in a fuel system of an internal combustion engine;

Figure 2 is a sectional view of a fuel vaporisation adaptor retrofitted to an inlet manifold of an internal combustion engine; and

Figure 3 is a plan and various sectional views of the vaporisation adaptor of Figure 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in Figure 1 there is a fuel vaporisation system shown generally within broken outline as 10 comprising a fuel vaporisation adaptor 12, heating means 14, a digital controller 16, and a temperature sensor 19. In this embodiment, the vaporisation system 10 is designed to retrofit to a fuel system of a conventional six cylinder internal combustion engine including a fuel pressure regulator 18, a fuel tank 20, fuel pumps 22, an intake manifold 24, a fuel rail 26, and an EFI system (not shown) . Either the existing fuel system or the fuel vaporisation system 10 may include a non-return valve located between the vaporisation adaptor 12 and the fuel pump 22.

The ghost outline of the flow diagram of Figure 1 represents an electronic control line. The vaporisation adaptor 12 is plumbed or conveniently retrofits between the fuel rail 26 and the intake manifold 24. The temperature sensor 19 is connected directly to the vaporisation adaptor 12. The digital controller 16 receives a temperature signal from the temperature sensor 19 whereupon it effects digital control of the heating means 14. The digital controller 16 may also regulate heating based on a pressure signal which is indicative of fuel flow rate.

Figure 2 illustrates a preferred embodiment of the vaporisation adaptor 12 fitted to an inlet manifold 13 with a conventional fuel injector 15 retracted from the adaptor 12. The adaptor 12 is generally die-cast in stainless steel and comprises a conical-shaped body portion 28 which defines an inlet bore 30 formed continuous with an outlet spigot 32 defining an outlet passageway 34. Alternatively the adaptor 12 may be formed of a pair of cylindrical sections which are designed to push fit and then be welded together to form the adaptor 12. The inlet bore 30 is shaped generally complementary to the fuel injector 15 which is retractably located within the inlet bore 30. A rubber seal or grommet 36 locates between the fuel injector 15 and a rebate 38 formed in the adaptor 12. The outlet spigot 32 is shaped substantially identical to a lower end of the fuel injector 15 and similarly includes an O-ring seal (not shown) which permits a corresponding press-fit of the vaporisation adaptor 12 into the inlet manifold 13.

As best shown in Figure 3 the vaporisation adaptor 12 includes a nichrome heating wire as the heating means 14 shaped in the form of a helix. The wire helix 14 is positioned co-axially within the outlet passageway 34 with one end being spot welded to the adaptor 12 and an opposite end welded or soldered to an electrical coupling 35 designed to connect to a power supply. The nichrome wire heating element 14 provides a variable resistance heating element which is capable of heating the fuel to about 235 ± 5°C to achieve around 90% vaporisation. The electrical coupling 35 of this example includes an impregnated glass fibre insulation sleeve 37. The wire helix 14 is wound within an insulation housing 39 which locates within the outlet passageway 34. The insulation housing 39 is formed of an alumina ceramic insert which is shaped generally cylindrical. The O-ring seal 40 is constructed of a high temperature VITON material and prevents the egress of vaporised fuel from the intake manifold 24 in which it is press-fitted. A thermocouple sensor 19 is connected to the adaptor 12 immediately downstream of the heating element 14. An elliptical-shaped plate 44 locates over the injector 15 and includes a pair of holes 46A/46B for fixing of the injector 15 within the adaptor 12.

The heating element 14 is activated by the digital controller 16 depending on the temperature of the fuel. In this example, the temperature sensor or thermocouple 19 provides the required signal for activation of the controller 16. A pressure sensor (not shown) may also be included in the fuel line for control of the heating means 14.

The digital controller 16 includes one or more circuit boards configured to activate the heating element 14 dependent on the temperature signal received from the thermocouple sensor 19. In this embodiment the digital controller 16 is configured so that the temperature of fuel within the outlet passageway 34 of the adaptor 12 is maintained at approximately 235 °C to achieve approximately 90% vaporisation of the fuel. Activation of the heating element 14 may also be varied by the pressure sensor 18 which generally indicates the flow of fuel to the vaporisation adaptor 12.

It is envisaged that incorporation of the vaporisation system 10 within a fuel system including EFI will require "adjustment" of the EFI system to correct for vaporisation of the fuels. In particular, it may be necessary to modify the injection pulse times relayed to the EFI injectors for the fuel system to adequately deal with vaporised as opposed to liquid fuels. For example, it may be necessary to "adjust" the pulse time from 3 to 0.5 milliseconds. This can be achieved by: 1. providing an interface between the digital controller 16 and the EFI system; or 2. retrofitting a converter board to the EFI system.

Another option, although this is not preferred, can involve reprogramming of the EFI system or vehicle computer.

The fuel vaporisation system 10 described above is well suited to retrofitting in a fuel system of a conventional internal combustion engine. It is envisaged that the system 10 will be supplied as a retrofit kit. The general steps involved in a retrofit include:

1. mounting of the digital controller within the engine bay area or interior cockpit;

2. insertion of each of the fuel vaporisation adaptors within the respective inlet of the intake manifold of the engine;

3. fitting of the fuel injectors to each of the vaporisation adaptors;

4. fitting of the fuel line and electronics to each of the fuel injectors; and 5. including the vaporisation system interface between the digital controller and the EFI system and if necessary reconfiguring the EFI system or computer vehicle.

It will be appreciated that fuel vaporisation system 10 lends itself to relatively lean fuel to air mixtures.

This is largely as a result of vaporisation of the fuel as effected by the digital controller. Furthermore "adjustment" of the EFI system similarly allows accurate burning of the fuel and air in stoichiometric amounts. In combination with the fuel vaporisation system the combustion process of a conventional internal combustion engine can be finely tuned and rapidly altered in response to changes in engine operating conditions. This permits leaner fuel to air mixtures without significant power reduction. Now that a preferred embodiment of the invention has been described in some detail, it will be apparent to those skilled in the art that the fuel vaporisation system has at least the following advantages: 1. the fuel vaporisation system can be retrofitted to a fuel system of a conventional internal combustion engine such as that in a motor vehicle, aircraft, ships or trucks; 2. the fuel vaporisation system provides effective and accurate fuel vaporisation through digital control; and 3. the fuel vaporisation system permits leaner mixtures of fuel to air approaching stoichiometric requirements and allows efficient burning of fuels so as to reduce greenhouse gas emissions.

Those skilled in the art will appreciate that the invention described herein is suitable to variations and modifications other than those specifically described. For example, the fuel vaporisation adaptor may be of practically any configuration provided it can be retrofitted to a conventional intake manifold and permits housing of a fuel injector which together allows for heating and vaporisation of fuel. The specific heating element described may be substituted with heating elements of other configurations.

All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A fuel vaporisation adaptor designed to retrofit to an intake manifold of an internal combustion engine, said adaptor comprising: a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore; and a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector, the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway.

2. A fuel vaporisation adaptor as defined in claim 1 wherein the inlet bore is shaped generally complementary to at least a portion of the fuel injector which thus fits within the inlet bore.

3. A fuel vaporisation adaptor as defined in claim 2 also including one or more annular seals disposed between the injector and the body portion of the adaptor.

4. A fuel vaporisation adaptor as defined in any one of the preceding claims further including an insulating housing located within the outlet passageway and surrounding the heating element.

5. A fuel vaporisation adaptor as defined in claim 4 wherein the insulating housing is a cylindrical-shaped housing formed of a ceramic material.

6. A fuel vaporisation adaptor as defined in any one of the preceding claims wherein the heating element is an elongate wire formed as a helix having its axis coaxial with that of the outlet passageway.

7. A fuel vaporisation adaptor as defined in claim 6 wherein the heating element is a variable resistance heating element which is capable of heating the fuel to between 210 to 260°C to achieve in excess of 90% vaporisation.

8. A fuel vaporisation adaptor as defined in any one of the preceding claims further including a temperature sensor connected to the body portion immediately downstream of the heating element.

9. A fuel vaporisation adaptor as defined in claim 8 wherein the temperature sensor is a thermocouple element.

10. A fuel vaporisation system designed to retrofit to an internal combustion engine, said system comprising: a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore; and a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector, the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway; and a digital controller operatively coupled to the heating element whereby in operation vaporisation of the fuel is controlled by the digital controller depending on the temperature and/or pressure of the fuel.

11. A fuel vaporisation system as defined in claim 10 wherein the digital controller includes one or more circuit boards being configured to activate the heating element dependent on temperature and/or pressure signals received from temperature and/or pressure sensors.

12. A fuel vaporisation system as defined in claim 10 or 11 also including an interface between the digital controller and an electronic fuel injection (EFI) system, the interface being designed to adjust the EFI system to correct for vaporisation of the fuel.

13. A fuel vaporisation system as defined in claim 10 or 11 further including a converter board operatively coupled to the EFI system so as to adjust the system, and in particular pulse signals for activating injector valves, to correct for vaporisation of the fuel.

14. A method of improving fuel combustion efficiency in a combustion engine, said method comprising the steps of: providing a fuel vaporisation adaptor including a body portion having an inlet bore being configured to retractably receive a fuel injector, and an outlet passageway formed continuous with the inlet bore; and a heating element connected to the body portion and positioned within the outlet passageway immediately downstream of the fuel injector retrofitting said vaporisation adaptor to an intake manifold of the combustion engine with the heating element being in direct contact with fuel ejected from the fuel injector and being configured to effect substantially complete vaporisation of said fuel which flows directly to the intake manifold via the outlet passageway.

15. A method as defined in claim 14 wherein retrofitting of the vaporisation adaptor involves additionally spacing the fuel rail from the intake manifold to accommodate the adaptor .