WO2008067623A1

WO2008067623A1 - Pneumatic cold start system for multifuel vehicles

Info

Publication number: WO2008067623A1
Application number: PCT/BR2006/000262
Authority: WO
Inventors: Herbert Costa
Original assignee: Delphi Technologies, Inc.
Priority date: 2006-12-06
Filing date: 2006-12-06
Publication date: 2008-06-12

Abstract

A fuel atomizer adaptable for use in cold starting a spark-ignited engine such as a single-cylinder motorcycle engine, especially when fueled by a low volatility fuel such as ethanol. The fuel atomizer comprises a nozzle (26) mounted in an engine air intake manifold (28), a pneumatic air tank (12), and an electrically-operated valve for dispensing air and fuel through the nozzle into the manifold. The air tank is filled by an air pump driven by the engine during periods of engine operation. The nozzle is preferably positioned such that atomized fuel is immediately mixed with air in the manifold. An engine control module monitors the fuel load being supplied to the engine at all times and varies the output of both the fuel atomizer and the individual fuel injectors in a smooth, fuel-efficient, start-up/warm-up protocol.

Description

PNEUMATIC COLD START SYSTEM FOR MULTIFUEL VEHICLES"

TECHNICAL FIELD

The present invention relates to internal combustion engines; more particularly, to devices for assisting in starting an internal combustion engine; and most particularly, to a pneumatic system for providing a combustible air/fuel mixture to the combustion chamber of such an engine, especially under cold-start conditions and especially for engines intended for use with a multiplicity of fuel types .

BACKGROUND OF THE INVENTION

Internal combustion engines fueled by a multiplicity of fuel types are well known. These engines are able to function, generally, on gasoline, ethanol, or any mixtures thereof, as may be available to an operator on a day-today basis or from one country to another.

In order to start and run, internal combustion engines must have a compressed fuel/air mixture that is combustible in a combustion cylinder. For spark-ignited gasoline-fueled engines, such a condition generally presents little problem except at extremely low temperatures. However, for engines fueled by fuels much less volatile than gasoline, for example, alcohols such as ethanol, or mixtures of ethanol and gasoline, starting can be difficult or impossible under low temperature conditions experienced seasonally in many parts of the world.

The problem is further exacerbated by the presence of water in such mixtures, as ethanol cannot be produced inexpensively as a pure compound but rather distills as a 95/5% ethanol/water azeotrope.

In countries where many modern vehicles are fueled by a 95/5/5% azeotrope, it is highly desirable to provide some means for enhancing the cold starting capabilities of such vehicles.

Most spark-ignited vehicles currently being produced for consumer use utilize fuel injectors for dispensing fuel into either the runners of an intake manifold ("port injection") or the cylinders themselves ("direct injection"). It is known to provide means for warming liquid fuel just before the point of injection, to assist in vaporization of the subsequently-injected fuel. See US Patent No. 5,690,080 which discloses within a fuel injector a fuel chamber containing a disk-shaped element formed of an electrically-resistive material having a positive temperature coefficient (PTC) of resistance which draws electric current to heat cold fuel passing by, but gradually shuts down as the fuel temperature is increased. Such an approach can be useful in enhancing starting of direct-injected engines, either spark-ignited or compression-ignited. A drawback is the requirement that all of the fuel injectors in the engine must be so equipped. Another drawback is that volatilization of the fuel is not caused directly and must be assumed to proceed spontaneously as a function of the total heat budget of the engine, air, and warmed fuel.

It is known to equip ethanol-fueled vehicles with an auxiliary fuel tank containing gasoline specifically to assist in starting the engine when cold by injecting gasoline into the engine intake manifold. However, this approach undesirably requires additional hardware, complexity, and manufacturing and operating cost, as well as a source of gasoline.

What is needed in the art is an improved means for enhancing the cold-starting capability of a port-injected, direct injected, or carbureted internal combustion engine, and especially a spark-ignited engine, when fueled by a fuel having relatively low volatility.

It is a principal object of the present invention to increase the ease and reliability of starting such an engine at relatively low ambient fuel and air temperatures.

SUMMARY OF THE INVENTION

Briefly described, in a fuel atomizer system in accordance with the invention, a fuel atomizer nozzle is disposed in the intake manifold of a spark- ignited internal combustion engine, which may be port-injected, direct-injected, or carbureted. The object of the fuel atomizer is to enrich, with atomized and vaporized fuel, the air passing through the manifold to the individual cylinders such that, upon compression within the cylinders, an explosive air/fuel mixture is created that can be discharged by a sparking plug. The fuel to be atomized is preferably drawn from the operating fuel tank of the engine.

The fuel atomizer may be sized such that its output is relatively low and suffices to augment the fuel being supplied ordinarily to the individual cylinders via their dedicated port or direct fuel injectors. Alternatively, the fuel atomizer may be sized such that its output is sufficient to create a combustible mixture within the intake manifold sufficient to start and run the engine without port or direct fuel injection for some period of time.

In either embodiment, a fuel atomizer in accordance with the invention comprises a dedicated fuel injection nozzle mounted in an engine air intake manifold, a pneumatic air tank, and an electrically-operated valve for dispensing an air/fuel mixture through the nozzle into the manifold. The air tank is filled to a high pressure by an air pump driven by the engine during periods of operation. Preferably, the nozzle is positioned within the manifold such that atomized fuel is immediately swept from the atomizer and mixed with air in the manifold; such a currently-preferred location is immediately downstream of the manifold air intake throttle valve.

Obviously, combinations of these two embodiments are also possible, and an engine control module can readily monitor the fuel load being supplied to the engine at all times and can controllably vary the output of both the fuel atomizer and the individual port or direct injectors in a smooth, fuel- efficient, start-up/warm-up protocol.

A fuel atomizer in accordance with the invention is readily adaptable for use in cold starting a spark-ignited engine, more especially a small engine such as a single-cylinder motorcycle engine, and most especially a small engine fueled by a low volatility fuel such as ethanol. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic drawing of a fuel atomizer system in accordance with the invention, shown in a first mode wherein a compressed air tank is filled;

FIG. 2 is a schematic drawing of the fuel atomizer system shown in

FIG. I₅ shown in a second mode wherein the compressed air tank is discharged to entrain and then inject atomized fuel into an engine manifold.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a fuel atomization system 10 for supplying atomized fuel to an exemplar port-injected internal combustion engine 11, in accordance with the invention, comprises a compressed air tank 12, and an air pump 14 for supplying compressed air to tank 12 through a first check valve 16. System 10 receives fuel from a prior art engine fuel rail 18 through a second check valve 20. Fuel rail 18 may be fluidly connected to conventional fuel injectors (not shown) for feeding fuel to the cylinders of engine 11 as known in the art. A third check valve 22 cooperates with second check valve 20 to prevent backflows between tank 12 from fuel rail 18. On command from an engine control module (ECM) 23, fuel and air from fuel rail 18 and tank 12, respectively, may be supplied through an electric control valve 24 to an atomizing nozzle 26 mounted within an engine intake manifold 28. The flows of fuel and air may be limited to the approximate fuel/air ratio and volume by, for example, fixed orifices 27,29, respectively.

In a first operating mode, shown in FIG. 1, valve 24 is closed, and tank 12 is filled 30 through first check valve 16 to a predetermined internal pressure by pump 14 which preferably is powered by engine 11 during operation thereof, for example, directly as by a belt or indirectly as by electric current generated by an engine driven alternator. Various sensors and controls, as are well known in the art of compressor controls, are obviously required but need not be shown in these drawings.

In a second operating mode, and referring now to FIG. 2, valve 24 is opened allowing air 32 to flow from tank 12 through third check valve 22. At junction 31, air 32 entrains fuel 34 that flows under pressure from fuel rail 18 through second check valve 20. The combined fuel 34 and air 32 pass through valve 24 and are discharged through nozzle 26, forming an atomized spray -36 within manifold 28.

System 10 is controlled by ECM 23. During normal engine operation (first mode), when the engine is running, pump 14 is turned on by ECM 23 to fill air tank 12. ECM 23 is provided with a temperature signal (not shown) and is programmed with an algorithm that engages system 10 during starting of engine 11 when the fuel in fuel rail 18 is recognized as a low- volatility fuel such as ethanol and when the ambient temperature is below a predetermined value, generally about 18oC, or the flash point of ethanol. System 10 may continue to be operated for some period of time after engine 11 starts, and may fuel engine 11 alone or may cooperate with and thereby supplement the engine's own fuel injection system, as may be desired. ECM 23 can readily monitor the fuel load being supplied to the engine at all times and can controllably vary the output of both the fuel atomizer and the engine's individual port or direct injectors (not shown) in a smooth, fuel-efficient, startup/warm-up protocol.

While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.

Claims

1. A fuel atomizing system for use in starting an internal combustion engine, comprising: a) a tank for receiving and dispensing compressed air; b) a fuel source; c) a valve, in flow communication with said tank and said fuel source, for controlling flows of said dispensed air and fuel from said fuel source; and d) a nozzle disposed in flow communication with at least one cylinder of said internal combustion engine for receiving said dispensed air and said fuel from said valve and for atomizing said dispensed flows air and fuel into said at least one engine cylinder.

2. A fuel atomizing system in accordance with Claim 1 wherein said engine includes an air intake manifold in flow communication with said at least one engine cylinder and said atomized flow of air and fuel is received by said air intake manifold from said valve.

3. A fuel atomizing system in accordance with Claim 1 further comprising pump for providing compressed air into said tank.

4. A fuel atomizing system in accordance with Claim 3 wherein said pump is energized by said engine.

5. A fuel atomizing system in accordance with Claim 3 further comprising a first check valve disposed between said pump and said tank.

6. A fuel atomizing system in accordance with Claim 1 further comprising a second check valve disposed between said fuel source and said valve.

7. A fuel atomizing system in accordance with Claim 1 further comprising a third check valve disposed between said tank and said valve.

8. A fuel atomizing system in accordance with Claim 3 further comprising an engine control module for controlling the action of said pump and said valve in response to a plurality of input signals.

9. A fuel atomizing system in accordance with Claim 8 wherein said input signals include an ambient temperature signal.

10. A fuel atomizing system in accordance with Claim 9 wherein said input signals further include a fuel type signal.

11. An internal combustion engine comprising a fuel atomizing system for use in starting said engine, said fuel atomizing system including a tank for receiving and dispensing compressed air, a fuel source, a valve, in flow communication with said tank and said fuel source, for controlling flows of said dispensed air and fuel from said fuel source, and a nozzle disposed in flow communication with at least one cylinder of said internal combustion engine for receiving said dispensed air and said fuel from said valve and for atomizing said flows of air and fuel into said at least one engine cylinder.