WO2008070895A1

WO2008070895A1 - Engine manifold and fuel delivery system

Info

Publication number: WO2008070895A1
Application number: PCT/AU2007/001741
Authority: WO
Inventors: Geoffrey Russell Turner; James Richard Hunt
Original assignee: Geoffrey Russell Turner; James Richard Hunt
Priority date: 2006-12-13
Filing date: 2007-11-13
Publication date: 2008-06-19

Abstract

An engine manifold is disclosed which has a manifold chamber (502) and a plurality of outlets (506) for supplying air and fuel to inlet ports of an engine. At least one partition (511) divides the chamber (502) into a plurality of chamber sections (510) each containing one of the outlets (506) to prevent fuel robbing by one outlet in a section for another outlet in a neighbouring section.

Description

ENGINE MANIFOLD AND FUEL DELIVERY SYSTEM

Field of the Invention

This invention relates to an engine manifold and to a fuel delivery system using the engine manifold.

Background of the Invention

Our Australian Provisional Patent Application No. 2006906054 describes a fuel delivery system for a diesel engine which concurrently supplies diesel fuel and liquid gas fuel for combustion in the engine.

The diesel fuel is typically injected directly into the cylinders of the engine and the liquid gas fuel is delivered to the inlet manifold of the engine for supply to the cylinder of the engine with air.

Conventional bi-fuel engines which use either liquid gas fuel or petroleum fuel as alternative fuels rather than concurrently as a combined fuel also can deliver fuel and air via the engine inlet manifold.

Furtherstill , engines which run on only one type of fuel also deliver a fuel air mixture to the engine via the inlet engine manifold.

For delivery of fuel via the engine manifold to the inlet ports of the engine can result in fuel robbing in which some of the fuel does not arrive at one of the inlet ports and more fuel than is required arrives at other inlet ports of the engine . This in turn results in inefficient or improper operation of the engine.

Summary of the Invention The invention provides an engine manifold for supplying air and fuel to an engine, comprising: a manifold body defining a main manifold chamber; an inlet for the supply of air to the chamber; a fuel inlet for supply of fuel to the chamber; a plurality of outlets from the chamber for communication with inlet ports of the engine for supply of air and fuel through the outlets to the inlet ports of the engine; and at least one partition for dividing the chamber into a plurality of chamber sections , each containing at least one of the outlets to thereby prevent fuel robbing by one outlet in a section from another outlet in a neighbouring section .

Preferably a plurality of partitions is provided for dividing the chamber into a plurality of sub-manifold chambers, each of the sections containing at least one of the sub-manifold chambers , and each sub-manifold chamber containing one of the outlets to thereby prevent fuel robbing by one of the outlets from a neighbouring outlet.

Preferably each partition comprises an internal wall located between adjacent outlets.

Preferably the inlet is arranged substantially centrally of the manifold body.

The invention also provides an engine having a fuel delivery system comprising: a fuel delivery device for delivering diesel fuel to each cylinder of the engine; an inlet manifold connected to the engine and having a manifold body defining a main manifold chamber; an inlet for the supply of air to the chamber; a fuel inlet for supply of fuel to the chamber; a plurality of outlets from the chamber for communication with inlet ports of the vehicle engine for supply of air and fuel through the outlets to the inlet ports of the engine; and at least one partition for dividing the chamber into a plurality of chamber sections, each containing at least one of the outlets to thereby prevent fuel robbing by one outlet in a section from another outlet in a neighbouring section .

Preferably the inlet is arranged substantially centrally of the manifold body.

Brief Description of the Drawings

A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings in which :

Figure 1 is a schematic diagram of a fuel delivery system for supplying concurrently diesel fuel and liquid gas fuel to a diesel engine ;

Figure 2 is a detailed view of the preferred embodiment of the invention;

Figure 3 is a top cross-sectional view showing four injection devices correctly aligned with the inlet ports of a cylinder head and attached to an inlet manifold according to the preferred embodiment of the invention;

Figure 4 is a plan view of the manifold of the preferred embodiment; and Figure 5 is a schematic perspective broken away view of the manifold of Figure 4. ■— Λ —

Description of the Preferred Embodiment

With reference to Figure 1 liquid petroleum gas tank 12 supplies liquid petroleum gas via tank lock 14 to service line 16 and onto inline filter 4. The filtered liquid petroleum gas is then conveyed through service line 37 to distribution block 38. From the distribution block 38 the liquefied petroleum gas liquid flows through insulated delivery lines 39 to injector housings 3 (shown in more detail in Figure 4) .

With reference to Figure 2 the liquefied petroleum gas from lines 39 enters housing 3, which will be described in detail with reference to Figure 4. The housing 3 has a liquid injector 20 for supplying liquid petroleum gas to engine E.

With liquid at injector 20 and a pulse width supplied from ECU 70 to injector 20 the liquid liquefied petroleum gas travels through the injector 20 and is ejected into manifold 32 (see Figure 3) , with the spray directed towards inlet port 29 (see Figure 3) . The injection of the liquefied petroleum gas is timed by the ECU 70 such that the pulse occurs after the closing of exhaust valve 133 (see Figure 3) and before the closing of the inlet valve 132 (see Figure 3) , such that the downward action of piston 131 (see Figure 3) can draw into engine E, all of the liquefied petroleum gas ejected with no blow-by passed exhaust valve 133.

The liquefied gas in the housing 3 which does not enter injector 20, and which can be in a vapour or liquid state, leaves the housing 3 through conduit 240. The conduit 240 passes through a bleed gas heater 250. The bleed gas heater 250 has an inlet 251a and an outlet 252a which can be connected in an engine cooling water conduit so that engine cooling water which is at a temperature of about 70⁰C passes through the heater 250 to supply heat to the heater 250 and, in particular, heat to the part of the conduit 240 which is inside the heater 250. Thus, any liquid gas which passes through the conduit 240 is heated and therefore converts to a vapour state if not already in a vapour state. The conduit 240 is connected to a bleed injector 260 which is designed to eject gas rather than liquid, and the injector 260 injects vapour into the inlet manifold 32, as is shown in Figure 2. The bleed injector 260 is controlled by the ECU 70 via pulses received on line 253. The pulses on the line 253, like the pulses on line 86, are timed such that the injector 260 is actuated when the inlet valve 132 is open and the exhaust valve 133 is closed, so that the liquid petroleum gas in vapour state is supplied to the engine E together with the liquid ejected from the injector 20. Thus, the supply of the vapour is controlled in the same manner as the liquid supply and therefore blow-through of vapour through the engine is prevented or at least greatly reduced. The injectors 260 are sized and the pulses supplied on line 253 of such a length that the desired amount of gas is injected into the engine such that emissions are not adversely affected and, at the same time, the cooling effect provided by the passage of liquid gas through the inlet 11, the housing 203 and the conduit 240 does not adversely affect the cooling of the injector 20.

The bleed gas heater 250 ensures that no liquid gas in the liquid state reaches the bleed injector 260, as this would alter the mixture due to the fuel density difference between liquid and gaseous liquid petroleum gas.

The heat supplied by the bleed gas heater 250 is preferably sufficient to ensure that the temperature is well above the liquid petroleum gas vaporisation point and relatively stable.

Figures 2 and 3 also show diesel injector 171 for supplying diesel fuel to the cylinder of the engine E concurrently with the supply of liquid petroleum gas via the injector 20 and the injector 260. Thus, by supplying fuel in the form of liquid petroleum gas from the injectors 20 and 260, the amount of diesel fuel which is required can be reduced, thereby increasing fuel economy compared to situations which would occur when only diesel fuel is supplied via the diesel injector 171. Furtherstill, by ensuring that the liquid gas which is bubbled off in the housing 203 and used to cool the injector 20 is again delivered to the engine in the form of vapour during the cycle of the engine when the exhaust valve 133 is closed and the inlet valve 132 is open, ensures that that fuel is efficiently used thereby increasing power, which means that not so much throttle pressure is required, thereby further reducing fuel. The fact that the fuel is supplied in this manner also prevents blow-through, which would not only waste the fuel, but also may well increase emissions to an undesirable level.

Full details of the housing 3 shown in Figures 1 to 3 are given in co-pending Australian Patent Application 2006906054. The contents of that patent application are incorporated into this specification by this reference.

Figures 4 and 5 show the manifold 32 in more detail except that the manifold shown in Figures 4 and 5 are applicable to a six cylinder engine rather than a four cylinder engine shown in Figure 3.

The manifold 32 has a manifold body 500 which defines a main manifold chamber 502. The chamber 502 has an inlet 504 for the inlet of air. Liquid gas fuel may be supplied to the manifold 32 by injectors of the type shown in

Figure 3 which are aligned with each of the outlets 506 of the manifold and which in turn connect with the inlet ports 29 of the engine. One of the housings 3 and injectors 20 is schematically shown in Figure 5.

The manifold chamber 502 is divided into a plurality of sub-manifolds 510 by internal walls 511 which extend between the adjacent outlets 506 and therefore separate the outlets 506 from one another. The walls 511 extend from wall 513 of the manifold which has the outlets 506 and terminate short of opposite wall 514. The walls extend all the way between top 515 and bottom 516 of the manifold 32.

Alternatively, rather than providing the housings 3 and injectors 20 aligned with each of the outlets 506, an injector can be provided for delivering fuel into the inlet 504.

Regardless of the location of the injection of the fuel, the fuel is drawn into the engine with air through the outlet 506 and inlet port 29 during movement of the pistons of the engine and opening of the inlet valves 132.

The internal walls 511 which divide the manifold chamber 502 into sub-chambers 510 prevent fuel robbing whereby fuel supplied to the chamber 510 tends to go more to one of the outlets 506 and therefore the cylinder associated with that outlet 506, rather than a neighbouring outlet 506 and the cylinder associated with that outlet 506.

The walls 511 provide good air separation so that air and therefore fuel is directed to each of the outlets 506 to thereby prevent one of the outlets 506 from robbing fuel from a neighbouring outlet 506.

As shown in Figure 4, the wall 511 which is generally aligned with the inlet 504 is slightly longer than the other walls . This wall provides separation between the inlet ports 506 to the left of the longer wall 511 and to the right of the longer wall 511. The specific walls between the adjacent outlets 506 then further divide the airflow so that good air separation is achieved and substantially equal amounts of air flow to each of the outlets 506 thereby drawing fuel to each of the outlets 506 and preventing fuel robbing from occurring.

The longer wall 511 therefore divides the chamber 502 into two chamber sections , one which contains three outlets and the other which also contains three outlets . This therefore separates the three outlets to the left of the longer wall 511 from those to the right of the longer wall 511 , and therefore prevents fuel robbing occurring by one of the outlets to the left from one of the outlets to the right of the longer wall . In particular embodiments of the invention, further sub-division of the manifold chamber may not be needed. Furthermore, whilst in the embodiment just described there are even numbers of outlets on each side of the longer wall, the longer wall could be located at a different position so that a different number of outlets are provided on each side of the longer wall , that is , the separation being between different numbers of outlets on the respective sides of the longer wall 511.

In the most preferred form of the invention the chamber is further sub-divided into the sub-manifolds by the shorter walls 511 as previously described, so that only one outlet is associated with each of the sub-manifold chambers and therefore, each outlet is effectively separated from each neighbouring outlet or outlets .

In the preferred embodiment of the invention, the engine is a diesel engine which is converted to run concurrently on diesel fuel and liquid gas fuel. However, in other embodiments, the engine could be a diesel engine which runs of bi-fuel, i.e. either on diesel fuel or on liquid gas fuel, or which is converted to run only on a liquid gas fuel or other fuel (other than diesel or petrol) .

Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove .

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense , i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention .

Claims

1. An engine manifold for supplying air and fuel to an engine, comprising: a manifold body defining a main manifold chamber; an inlet for the supply of air to the chamber; a fuel inlet for supply of fuel to the chamber; a plurality of outlets from the chamber for communication with inlet ports of the engine for supply of air and fuel through the outlets to the inlet ports of the engine ; and at least one partition for dividing the chamber into a plurality of chamber sections , each containing at least one of the outlets to thereby prevent fuel robbing by one outlet in a section from another outlet in a neighbouring section .

2. The engine manifold of claim 1 wherein a plurality of partitions is provided for dividing the chamber into a plurality of sub-manifold chambers , each of the sections containing at least one of the sub-manifold chambers , and each sub-manifold chamber containing one of the outlets to thereby prevent fuel robbing by one of the outlets from a neighbouring outlet.

3. The engine manifold of claim 1 wherein each partition comprises an internal wall located between adjacent outlets.

4. The engine manifold of claim 1 wherein the inlet is arranged substantially centrally of the manifold body.

5. A fuel delivery system comprising: a fuel delivery device for delivering diesel fuel to each cylinder of the engine; an inlet manifold connected to the engine and having a manifold body defining a main manifold chamber; an inlet for the supply of air to the chamber; a fuel inlet for supply of fuel to the chamber; a plurality of outlets from the chamber for communication with inlet ports of the vehicle engine for supply of air and fuel through the outlets to the inlet ports of the engine; and at least one partition for dividing the chamber into a plurality of chamber sections, each containing at least one of the outlets to thereby prevent fuel robbing by one outlet in a section from another outlet in a neighbouring section.

6. The fuel delivery system of claim 5 wherein a plurality of partitions is provided for dividing the chamber into a plurality of sub-manifold chambers, each of the sections containing at least one of the sub-manifold chambers , and each sub-manifold chamber containing one of the outlets to thereby prevent fuel robbing by one of the outlets from a neighbouring outlet.

7. The fuel delivery system of claim 5 wherein each partition comprises an internal wall located between adjacent outlets.

8. The fuel delivery system of claim 5 wherein the inlet is arranged substantially centrally of the manifold body.