Internal-combustion engines – Charge forming device – Heating of combustible mixture
Patent
1996-08-16
1997-12-09
McMahon, Marguerite
Internal-combustion engines
Charge forming device
Heating of combustible mixture
123533, F02M 5306, F02M 6904, F02M 3118
Patent
active
056949065
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention concerns a fuel injection system for an internal combustion engine.
BACKGROUND INFORMATION
A fuel injection system having an injection valve and a fuel vaporizer connected to it is already known from SAE article 930710 "Cold start performance of an automotive engine using prevaporized gasoline." The fuel vaporizer there consists of an electrically heated tube into which the fuel is injected from the injection valve.
To bring the stream of fuel in contact with the inside wall of the tube so the fuel will be vaporized, three compressed air nozzles are provided in the connection area between the fuel vaporizer and the injection valve, so that one nozzle injects air radially to the fuel to deflect the stream of fuel while the two other nozzles inject the air tangentially to cause the deflected fuel stream to rotate, so the fuel stream moves essentially in a spiral line through the electrically heated vaporizer tube.
German Patent Application NO. DE 2,843,534 describes another fuel injection system with an injection valve, where the outlet channel connected to the injection orifice of the injection valve has an electric heating element to vaporize the fuel sprayed onto it. An air jet opens into the area of the outlet channel between the injection orifice of the injection valve and the heating element, and by utilizing the pressure gradient in the intake tube, the air jet receives air from the intake tube which is then added to the fuel stream from the injection valve.
Use of fuel vaporizers in fuel injection systems has proven successful in reducing pollution emissions when starting up a combustion engine. Such a reduction in pollutant emissions is necessary until the catalyst integrated into the exhaust system of the combustion engine has reached its operating temperature, when it becomes fully functional. However, as soon as the catalyst has been heated to its operating temperature, prevaporization of the fuel is no longer necessary, so the fuel vaporizer can be turned off in normal operation of the combustion engine. However, if the fuel vaporizers that are connected directly to the injection valve are not heated electrically, problems occur in producing the fuel-air mixture, because the fuel vaporizer impairs the fuel stream produced by the injection valve and thus interferes with fuel delivery.
SUMMARY OF THE INVENTION
The system according to the present invention has the advantage in comparison with the prior art that the vapor jet leaving the fuel vaporizer is shaped by the supply of air in the area of the outlet orifice of the fuel vaporizer, and furthermore improved atomization of the ejected fuel stream is achieved while the fuel vaporizer is not operating, i.e., the fuel vaporizer is not heated.
It is especially advantageous that appropriate guidance of the air to be mixed with the fuel stream produces a suction effect that greatly improves fuel delivery from the vaporization area of the fuel vaporizer. Especially suitable nozzles include annular gap nozzles and nozzles with several orifices arranged around the outlet orifice of the fuel vaporizer through which air can be injected essentially radially into the fuel stream leaving the fuel vaporizer. Thanks to the suction effect achieved according to this invention, fuel deposits on the inside walls and on the vaporizer structure can be prevented especially in an unheated fuel vaporizer.
It is especially advantageous if the blow-out orifice is designed so its effective cross section determines how much air is to be added to the fuel stream. As an alternative, the air inlet system may be connected to an idling air regulator of a combustion engine, so all the idling air is added to the fuel stream through the air supply system.
For even better prevention of fuel deposits with unheated fuel vaporizers, it is advantageous to also provide an air supply to the inlet orifice of the fuel vaporizer in addition to the air supply in the area of the outlet orifice, thus purging the vaporizer area and the vaporizer struc
REFERENCES:
patent: 4325341 (1982-04-01), Yamauchi et al.
patent: 4572146 (1986-02-01), Grunwald et al.
patent: 4604975 (1986-08-01), Frey et al.
patent: 4627405 (1986-12-01), Imhof et al.
patent: 4676216 (1987-06-01), Ohsawa et al.
patent: 5129381 (1992-07-01), Nakajima
patent: 5156133 (1992-10-01), Sugimoto et al.
patent: 5218943 (1993-06-01), Takeda et al.
patent: 5255658 (1993-10-01), Hoffer et al.
SAE article 390710 "Cold Start Performance of an Automotive Engine Using Prevaporized Gasoline".
Gladigow Herbert
Lange Jorg
McMahon Marguerite
Robert & Bosch GmbH
Texas Instruments Holland B.V.
Ulev GmbH
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