WO1996017164A1

WO1996017164A1 - Fuel vaporisation apparatus

Info

Publication number: WO1996017164A1
Application number: PCT/AU1995/000534
Authority: WO
Inventors: Alan Fraser Simpson; Graeme George Hearn
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-11-25
Filing date: 1995-08-25
Publication date: 1996-06-06
Anticipated expiration: 1997-05-25
Also published as: AUPM967894A0

Abstract

A fuel vaporisation apparatus for an engine having a manifold and a fuel metering device, including a chamber (52) which is connected between the fuel metering device and the manifold, which chamber (52) includes at least one baffle (62) therein, wherein the chamber (52) further includes means (74) for draining or removing any unvapourised fuel and impurities therefrom. The chamber (52) preferably includes at least two baffles (62, 64), each baffle (62) having at least one aperture (68) formed therein and the baffles (62, 64) divide the chamber into at least three sections. An elongated pipe connecting the apparatus to the fuel metering device may have internal ribs which promote greater vaporisation of the fuel and separation of unvapourised fuel and impurities. The elongated pipe preferably has at least one change of direction which is further preferably in a looped shape or in an S-bend configuration.

Description

TITLE

FUEL VAPORISATION APPARATUS

DESCRIPTION

The present invention relates to an apparatus for improving fuel vaporisation. More

S particularly, the present invention relates to an apparatus for improving fuel vaporisation for such fuels as petrol, alcohol, LPG and the like.

FIELD OF THE INVENTION There are grave concerns over the effect that emissions from motor vehicles are having on the environment. Consequently, there are now statutory requirements for Hydrocarbons, Carbon Monoxide and Nitrogen Oxides. These are still excessive and there are no emission levels of the Greenhouse gas carbon dioxide. Many of the emissions from motor vehicles are caused through incomplete combustion of the fuel. The incomplete combustion of the fuel arises, at least in part, due to the fact that many fuels are not completely vaporised when combustion commences. Also, many fuels have impurities which do not allow complete combustion of the fuel.

It would therefore be desirable if all of the fuel was vaporised and impurities removed before combustion commenced. Further, it would be desirable if existing vehicles could be retrofitted to reduce emissions therefrom. French Patent number FR,A,2053750 discloses the feature of a pipe from the manifold to a fuel system in an internal combustion engine where there is a central fuel draining system. However, this fuel draining system relates to a carburettor over flow device to compensate for excess fuel which is redirected back into the venturi. German Patent specification DE,A,2551901 discloses a pipe extending from the manifold to a fuel metering system where there is a central member 7 which drains the fuel. This German patent refers to a drain pipe which heats the petrol by discharging the fuel onto a hot valve.

Japanese Patent application number JP,A,62- 107259 discloses an air bypass pipe near the intake port of an intake pipe. A communication pipe joins the intake pipe to a fuel mixer and also provides a fuel liquid film catching member. This Japanese document refers to an excess fuel drain off pipe.

US Patent number 4132207 discloses a vehicle fuel injection system. The patent specification shows a tube from the discharge opening passing exteriorly of the mixing manifold wherein the tube has at its middle portion a housing chamber which draws the fuel and vaporises the fuel and then reintroduces the fuel via a pipe back into the fuel system.

The prior art does not seek to remove impurities from the fuel. The prior art either attempts to only drain the fuel into a bypass pipe and heat or pressurise the fuel, and then reintroduce the heated or pressurised fuel back into the fuel line with impurities. The prior art also does not seek to provide a dry vapour mixture of fuel to the engine's manifold system for distribution to the engine cylinders with minimal impurities.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a fuel vapourisation apparatus for an engine having a manifold and a fuel metering device characterised by including a chamber connected between the fuel metering device and the manifold, which chamber includes an inlet, an outlet and at least one baffle therein which baffle is pervious to air/fuel mixture, wherein the chamber further includes a drain means for removing unvapourised fuel and impurities therefrom. Preferably, the chamber includes at least two baffles, each baffle having at least one aperture formed therein and dividing the chamber into at least three sections.

Preferably, the chamber has four sections therein.

Further, the elongated pipe is preferably arranged so as to force fuel vapour to undergo at least one direction change preferably as a plurality of direction changes and also the elongated pipe preferably has a length in the range of 600 to 1500 mm and more preferably about 1000mm.

Still more preferably, the elongated pipe is annular in shape and has a ribbed internal surface, either circumferentially, longitudinally, helically (either left or right handed) or any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompany drawings, in which: Figure 1 is a schematic view of a fuel vaporisation apparatus in accordance with the present invention;

Figure 2 shows an expanded view of an elongated pipe used in the present invention;

Figure 3 is a cross-sectional view of the elongated pipe as shown in Figure 2;

Figure 4 shows the elongated pipe of Figure 2 arranged in a first configuration to cause fuel vapour to undergo directional changes;

Figure 5 shows the elongated pipe of Figure 2 arranged in a second configuration to cause fuel vapour to undergo directional changes;

Figure 6 is a perspective view of a chamber of the fuel vaporisation apparatus of Figure

1 to an enlarged scale. DESCRIPTION OF THE INVENTION

In Figure 1 there is a shown a fuel vaporisation apparatus 10 for an engine having a manifold 40 and a fuel metering device 50, including an elongated pipe 12, having a first end 14 and a second end 16. A chamber 52 is connected to the first end 14 of the elongated pipe 12. The elongated pipe 12 is preferably looped. The chamber 52 is then connected to a short delivery hose 75. The hose 75 is then connected to an inlet butterfly valve 73 which is in turn connected to the manifold 40. The chamber 52 includes a pair of draining pipes 76 which end in a holding tank 78.

In Figure 2 there is shown an expanded view of the elongated pipe 12. A plate 20 is provided at the second end 16. The plate 20 has 4 holes 22 provided therein to allow connection to the engine's fuel metering device 50. The plate 20 further has an aperture

23 provided therein. The aperture 23 is of a similar size to the fuel metering device's outlet.

The holes 22 and the plate 20 allow a convenient means for the elongated pipe 12 to be screwed or bo ed to the engine's fuel metering device 50. The fuel metering device 50 can be of any known type which supply a fuel/air mixture, such as a carburettor or fuel injection. Because of the accurate control afforded by fuel injection, it is preferred that the fuel metering device 50 is of the fuel injection type. 5 The elongated pipe 12 may be of a larger diameter than the outlet of the fuel metering device, thereby allowing increased vapourisation of fuel entering the elongated pipe 12. The elongated pipe 12 has sufficient length to allow an extended period of time for vaporised fuel to separate from the unvapourised fuel and impurities. The elongated pipe 12 preferably has a length from 600 to 1500 mm. The elongated pipe 12 is most preferably

10 1000mm in length.

In Figure 3 there is shown a cross section of an elongated pipe 12. Ribs 24 are provided on an internal surface 26 of the elongated pipe 12. The ribs 24 may extend circumferentially around the elongated pipe 12, or may extend longitudinally along the elongated pipe 12, or may extend helically along the elongated pipe 12, or any

15 combination of these types. Further, the ribs 24 may be male or female, that is they may project from the internal surface 26 or they may be recessed into the internal surface 26. To further assist in fuel vapourisation, it is preferable that the elongated pipe 12 causes fuel/air mixture to undergo directional changes. Figures 4 and 5 show two alternate arrangements of the elongated pipe 12 which provide 0 directional changes in fuel vapour. In Figure 4, the elongated pipe 12 is looped at 25 so as to require the fuel/air mixture to undergo a plurality of changes of direction. It should be appreciated that more than one loop may be provided in the elongated pipe 12. In Figure 5, the elongated pipe 12 is shown in a configuration having a plurality of S bends 27, which again forces the fuel/air mixture to undergo a plurality of changes of 5 direction. It should be appreciated that combinations of the arrangement shown in Figures 4 and 5 may be adopted, as may any other suitable arrangement. Shown in Figure 6 is a chamber 52 having a first end 54, a top 55, a second end 56 and a bottom 57. The first end 54 has an aperture 58 formed therein. The second end 56 has an aperture 60 formed therein. The apertures 58 and 60 are formed below the centre of the first end 54 and the second end 56, respectively. Other than the apertures 58 and 60, the chamber 52 is closed in use. The bottom 57 is cambered as shown in Figure 6. Three baffles 62, 64 and 66 are provided in the chamber 52. The baffles 62,64 and 66 are 5 disposed parallel to the ends 54 and 56 and are approximately equidistantly spaced therebetween. The baffles 62, 64 and 66 each have at least one aperture 68 formed therein. The baffles 62 and 66 each have two apertures 68 formed therein while the baffle 64 has a single aperture 68. An aperture 68 is disposed centrally and close to the bottom 57 in the baffle 64. Further, two apertures 68 are disposed off-centre and close to the top

10 55 in the baffles 62 and 66.

The baffles 62, 64 and 66 extend across the width of the chamber 52, however the baffles 62, 64 and 66 extend to the full height of the chamber 52, a gap 70 is formed between each of the baffles 62, 64 and 66 and one side of the bottom 57 of the chamber 52 and similarly a gap 72 is formed between each of the baffles 62, 64 and 66 and the bottom 57 5 of the opposite side of the chamber 52.

A draining means 74 is further provided, comprising a pair of draining pipes 76 attached to the bottom 57 of the chamber 52 adjacent the second end 56 on opposing sides thereof. The draining pipes 76 drain to a holding tank 78 via a pipe 77, optionally utilising a pump or the engine vacuum by means not shown. Further, the chamber 52 is mounted in an 0 inclined manner such that the chamber 52 slopes downwardly towards the second end 56. In use, unvapourised fuel within the chamber 52 is displaced towards the second end 56 under the influence of gravity. The cambered bottom 57 ensures unvapourised fuel and impurities will collect where the drain pipes 76 can remove the unvapourised fuel and impurities from the chamber 52. The gaps 70 and 72 between the baffles 62,64 and 66 5 and the bottom 57 provide a mechanism for unvapourised fuel and impurities caught between the baffles 62 and 64, or between the baffles 64 and 66 or between the baffle 66 and the first end 54 to drain to the draining means 74. In use, the first end 14 of the elongated pipe 12 is attached to the chamber 52 and the second end 16 is attached, by the plate 20, to the fuel metering device of the engine. Since the elongated pipe 12 is of a substantial length in the range of 600 to 1500 mm, more time is provided for unvapourised fuel in the fuel/air mixture to vapourise. If ribs 24 are provided in the elongated pipe 12, then unvapourised fuel has an increased surface area in which to vapourise. Preferably, the elongated pipe 12 has an arrangement such as that shown in Figures 4 or 5 to require the air and fuel mixture to undergo a plurality of directional changes. As the fuel/air mixture undergoes a directional change there is an increase in the turbulence therein so that the vapourisation of unvapourised fuel droplets will be enhanced. In use, the chamber 52 is connected to the engine's manifold and the elongated pipe 12. The second end 14 of the elongated pipe 12 is attached to the second end 56 such that fuel and air from the elongated pipe 12 enter through the aperture 60. Further, the manifold inlet butterfly valve 73 is attached to the second end 54 via a short hose 75 such that fuel/air mixture is drawn through the aperture 58 into the manifold 40. As fuel and air is drawn into the chamber 52, through the aperture 60, the baffles 62,64 and 66 create turbulence within the chamber 52. As fuel/air mixture enters the chamber 52 through the aperture 60, it is deflected by the baffle 62 and circulates in the region of the chamber 52 between the end 56 and the baffle 62 before being drawn through the apertures 68 in the baffle 62. The fuel/air mixture then circulates between the baffles 62 and 64 before being drawn through the aperture 68 in the baffle 64. Again, the fuel/air mixture is caused to circulate between the baffle 64 and 66 before passing through the apertures 68 in the baffle 66. Finally, the air and fuel again circulates between the baffle 66 and the first end 54 before being drawn through the aperture 58 into the hose 75 and then through to the inlet manifold butterfly valve 73 of the engine.

By offsetting the positions of the apertures 68 in the baffle 62 with respect to the aperture 60, a turbulent flow is provided along with slowing the charge velocity to facilitate further vapourisation. Further, the baffle 64 has only a single aperture 68, again offset from the apertures 68 in the baffle 62 to further promote vapourisation. Similarly, the baffles 66 has two apertures 68 formed therein which are offset from the aperture 68 in the baffle 64 to again facilitate vapourisation. Finally, the apertures 68 in the baffle 66 are offset from the aperture 58 to provide further vapourisation. A significant proportion of unvapourised fuel and impurities which enters the chamber 52 through the aperture 60 will initially impact the baffle 62 . Any residual, entrained unvapourised fuel and impurities will tend to impact either the baffle 64, the baffle 66 or the first end 54. As the unvapourised fuel and impurities is deposited on one of the baffles 62,64 and 66, or the first end 54 it will run down the respective baffle or the end 54 and collect on the bottom 57.The coUected material runs to the draining means 74 under the influence of gravity because of the incline of the bottom 57. Any unvapourised fuel which reaches the draining means 74 is likely to have a high degree of contaminants and therefore not be a useful contributor to combustion. It should be appreciated that the number of baffles which are provided may be varied, and further that the number of apertures formed therein and the positions therefor may also be varied. Further, the baffles 62,64 and 66 may be formed of a porous material to allow unvapourised fuel to be absorbed therein. A porous material may have to be periodically cleaned and/or replaced. By combining the elongated pipe 12 and the chamber 52, a fuel vaporising apparatus 10 is produced which provides a greatly increased opportunity for the maximum amount of fuel to vaporise and produce a dry air/fuel mixture by the removal of any non volatile fuel and impurities prior to the mixture being delivered to the engine manifold 40 via the butterfly valve 73. Further, the fuel vaporisation apparatus 10 of the present invention may be earthed to prevent build up of static electricity. There may also be a number of flame arresters between the elongated pipe 12, chamber 52 and the short hose 75. The fuel vaporisation apparatus of the present invention produces a continuous dry, vapour mixture under all conditions, e.g. cold start, idle, cruise and full load and is reliable since there are no moving parts. The fuel vaporisation apparatus provides vaporisation of fuel without heating the fuel mixture or using fuel additives.

EXAMPLES OF THE INVENTION

A sample of exhaust emissions were taken from a 1968 6 cylinder Holden engine during dynamometer testing. The first sample (A) was taken with the engine fitted with a fuel vaporisation apparatus fitted in accordance with the present invention. The second comparison sample (B) was taken from the same vehicle under similar conditions without the vaporisation apparatus fitted.

A B Carbon Monoxide 0.2% 6.5%

Hydrocarbons 175 P.P.M. 500 P.P.M.

Further analysis of the engines exhaust emissions by the W.A. Government Chemistry

Centre verified the dynamometer results. The chemistry report also noted a "more complete fuel burn" in the modified Holden and an increased nitrogen oxide level when compared to the standard vehicle.

A comparative emission testing was completed on a 19924000 km Australian Ford Laser vehicle fitted with Australian compliance emission devices and catalytic converter and without the fuel vaporisation apparatus. The levels were:

Carbon Dioxide (COz) 12% Carbon Monoxide (CO) 1.9%

Oxygen (O^ 1%

Hydrocarbons (HC) 500 ppm

The fuel vaporising system was fitted to a second test engine with an improved fuel metering device, (constant vacuum carburettor) and a catalytic converter fitted. The exhaust emissions were again analysed by the W.A. Government Chemistry Centre with the following verified results.

Carbon Dioxide 7%

Carbon Monoxide 10 P.P.M. Oxygen 13%

Hydrocarbons 20 P.P.M.

Nitrogen Oxides 12 P.P.M.

A comparison emission sample with the catalytic converter removed was analysed with fiirther reductions being recorded for carbon dioxide down to 5.5% and nitrogen oxides reduced to 1.5 P.P.M. It is evident from the high free oxygen level and significant decrease in carbon dioxide level that the engine's thermal efficiency has been dramatically increased resulting in improved fuel economy.

Modifications and variations such as would be deemed apparent to a skilled addressee are deemed within the scope of the present invention.

Claims

1. A fuel vapourisation apparatus for an engine having a manifold and a fuel metering device characterised by including a chamber connected between the fuel metering device and the manifold, which chamber includes an inlet, an outlet and at least one baffle therein which baffle is pervious to air/fuel mixture, wherein the chamber further includes a drain means for removing unvapourised fuel and impurities therefrom.

2. A fuel vaporisation apparatus as defined in claim 1, characterised in that the chamber includes at least two baffles therein thereby dividing the chamber into at least three sections.

3. A fuel vaporisation apparatus as defined in claim 1 or 2, characterised in that the chamber has a laterally sloped bottom and is longitudinally inclined so that unvapourised fuel and impurities will collect at the drain means.

4. A fuel vapourisation apparatus as defined in claim 1, 2 or 3 characterised in that the baffles contain aperture means.

5. A fuel vapourisation apparatus according to claim 4 characterised in that the aperture means is a baffle adjacent to the inlet and is vertically offset from the inlet, and the aperture means in each succeeding baffle are vertically opposed from the aperture means in the preceding baffle.

6. A fuel vaporisation apparatus as defined in any one of the preceding claims, characterised in that the fuel vaporisation apparatus further includes an elongated pipe connected between the chamber and the fuel metering device, such that the elongated pipe delivers an air/fuel mixture with increased vapourisation to the chamber.

7. A fuel vaporisation apparatus as defined in claim 6 characterised in that the elongated pipe is arranged so as to cause the air/fuel mixture to undergo at least one change in direction.

8. A fuel vapourisation apparatus according to claim 7 characterised in that the elongated pipe is arranged so as to cause the air/fuel mixture to undergo a plurality of changes of direction.

9. A fuel vapourisation apparatus according to claims 7 and 8 characterised in that the elongated pipe is looped or is in a configuration having a plurality of S bend.

10. A fuel vaporisation apparatus according to any one of claims 6 to 9 characterised in that the elongated pipe has an internally ribbed configuration which promotes enhanced vapourisation of the fuel.

11. A fuel/air mixture vapourisation apparatus according to any one of claims 6 to 10 characterised in that the elongated pipe is in a range of 600 to 1500 mm in length.