Internal-combustion engines – Charge forming device – Auxiliary air or gas used to inject fuel
Patent
1998-01-21
1999-02-16
Solis, Erick R.
Internal-combustion engines
Charge forming device
Auxiliary air or gas used to inject fuel
F02M 2300
Patent
active
058709983
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to an internal combustion engine having one or more combustion chambers each having an intake port, a fuel injector for injecting fuel into the intake port and means for supplying pressurised gas to assist in fuel atomisation of the fuel metered through the fuel injector.
BACKGROUND OF THE INVENTION
Fuel injection systems with air assisted fuel injection to improve fuel atomisation are well known. The gas supply to the injectors has in the past been drawn from a variety of sources. In the simplest form of such systems, ambient air is used to assist atomisation and is drawn into the intake port near to the fuel jet by the manifold vacuum. Such a system can only be used under low load conditions when the intake manifold vacuum is high and is not effective under high engine load conditions.
Other systems have been proposed that use gas from a rail that is pressurised in some manner when the engine is in operation. The rail can be pressurised by an engine driven compressor or by connecting it through one-way valves to the engine combustion chambers. In the latter case, the pressure in the rail may be too high, in which case a regulator is needed to reduce the delivery pressure of the gas to the intake ports.
The disadvantages with such systems is that the rail is permanently under pressure and delivers gas continuously to the intake ports, even at times when it is not required. As drawing gas from the combustion chambers of the engine or using the engine to drive a compressor both take power from the engine, this continuous supply of gas amounts to a waste of energy that increases fuel consumption.
One can use timed ON/OFF valves to limit the supply of gas from the compressed gas rail to the intake ports to the instants when it is required for fuel atomisation, but this increases system complexity and cost.
OBJECTIVE OF THE INVENTION
The present invention therefore seeks to provide an engine in which gas for assisting in fuel atomisation may be provided intermittently in an inexpensive and energy efficient manner.
SUMMARY OF THE INVENTION
In accordance with a first aspect of the present invention, there is provided an internal combustion engine having one or more combustion chambers each having an intake port, a fuel injector for injecting fuel into the intake port and means for supplying pressurised gas to assist in fuel atomisation of the fuel metered through the fuel injector, characterised in that the means for supplying pressurised gas comprises a passage incorporating a passive flow restrictor having no moving elements, the passage leading from one of the combustion chambers of the engine to the intake port and being operative to deliver a single pulse of gas to the intake port during each combustion cycle of the engine in order to assist in the atomisation of fuel injected into the intake port at the same time as the pulse of gas.
According to an alternative aspect of the invention, there is provided an internal combustion engine wherein each combustion chamber of the engine is connected to an intake port via a passage passing through the wall of the combustion chamber, the passage containing at least one passive flow restricting element to permit flow of gas in either direction driven by pressure pulses in the combustion chamber, and being operative to supply a pulse of gas into the intake port once during each combustion cycle to assist in fuel atomisation.
The invention differs from the prior art proposals using a pressurised rail in that the passages connecting the combustion chambers to the intake ports are all separate and not combined into a common supply rail. Furthermore, the individual passages do not contain a large buffer volume that would tend to even out the pressure pulses from the engine combustion cycles but instead make use of these dynamic pressure pulses to provide a pulsed gas supply to the intake ports. It is also important to note that the passage in the invention contains only passive components and has no moving part
REFERENCES:
patent: 1261466 (1918-04-01), Weiss
patent: 4716877 (1988-01-01), Duret
patent: 4771754 (1988-09-01), Weiss
patent: 5027765 (1991-07-01), Duret
patent: 5095881 (1992-03-01), Nishimura et al.
patent: 5390647 (1995-02-01), Schechter
Ferraro Neil P.
Ford Global Technologies Inc.
Solis Erick R.
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