Internal-combustion engines – Charge forming device – With fuel pump
Patent
1993-10-12
1995-12-26
Moulis, Thomas N.
Internal-combustion engines
Charge forming device
With fuel pump
123447, 123533, F02D 4134, F02M 6914
Patent
active
054778336
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a fuel system for delivering metered quantities of fuel to an internal combustion engine and is particularly applicable to fuel systems incorporating a fuel injector which can deliver fuel either directly to the engine combustion chamber or to the air induction system of the engine.
It is customary to provide in a fuel injection system a fuel pressure regulator to maintain the fuel supply at a preset pressure, as the pressure of the fuel is relevant to the process of motoring the fuel to the engine. Where a conventional pressure regulator is used, it is necessary to provide a fuel return line from the regulator to the fuel reservoir, thus effectively doubling the length of fuel line between the fuel reservoir and the fuel injection equipment that convey fuel at high pressure. The increase in fuel line length represents an expense in both the supply of material and assembly thereof, and also significantly increases the risk of high pressure fuel leakage developing.
From the point of view of safety, and also economy, it is desirable to reduce the extent of fuel lines between the fuel reservoir and the engine. This is particularly so in marine engine installations where leaked fuel can collect in an enclosed area and present a major fire hazard.
More importantly the energy consumed in pumping fuel at a rate substantially in excess of the engine fuel requirement represents a significant energy waste. Currently the fuel pump in a fuel injection system is normally electrically driven and operates continuously, thus consumes substantial electrical energy circulating fuel that is not required. This energy waste particularly occurs during low to medium load and/or speed operation of the engine and as the energy to drive the fuel pump is supplied directly or indirectly from the engine, energy wasted in pumping excess fuel represents a significant component of the fuel consumption of the engine.
There has been proposed such as in U.S. Pat. Nos. 3,967,598 and 4,565,173, fuel injection systems wherein the fuel pump is operated cyclically so as to maintain a substantially constant fuel supply pressure to the injector, and also so as to avoid the necessity of providing a return fuel circuit from the pump to the fuel tank or reservoir.
In both of these proposals, the fuel pump is required to operate at a duty cycle, directly related to the injection frequency, which in turn is related to engine speed. A pump operating on a duty cycle of such high frequency inherently has a low pumping efficiency, and consequently a low energy consumption efficiency. Further, the operation of a pump in a high frequency cycling mode severely reduces the life of the pump.
Although the fuel system proposed in U.S. Pat. No. 3,967,598 does provide an accumulator downstream of the fuel pump, the pump is still required to operate on a cyclic basis at a frequency equal to the frequency of injection. The accumulator is only provided for the purpose of attempting to substantially maintain the designed pressure for the supply of fuel to the injector and to overcome mechanical and hydraulic induced time delays which would otherwise prevent the attaining of substantial synchronism between the injector cycle and the pump cycle.
It is the object of the present invention to provide a method and apparatus for the supply of fuel to an engine which enables the maintenance of accurate metering of the fuel to the engine in accordance with the engine fuel demand, avoids the necessity of a high pressure fuel return line to the fuel reservoir and improve the operational efficiency of the fuel pump.
With this object in view there is provided according to the present invention a method of operating a fuel system supplying metered quantities of fuel for delivery to an internal combustion engine, said system having a cyclically operable fuel pump, a metering means to receive fuel supplied by the pump, and a processor to control the metering means to deliver a metered quantity of fuel to the engine, said processor determining the metered quan
REFERENCES:
patent: 3967598 (1976-07-01), Rachel
patent: 4248194 (1981-02-01), Drutchas et al.
patent: 4565173 (1986-01-01), Oshiage et al.
patent: 4920942 (1990-05-01), Fujimori et al.
patent: 4940034 (1990-07-01), Heim et al.
patent: 4951636 (1990-08-01), Tuckey et al.
patent: 4955350 (1990-09-01), Albertson
patent: 4971005 (1990-11-01), Dyer et al.
patent: 4989568 (1991-02-01), Sougawa
patent: 4993394 (1991-02-01), McKay et al.
patent: 5055758 (1991-10-01), Hock
patent: 5156133 (1992-10-01), Sugimoto et al.
patent: 5237975 (1993-08-01), Betki et al.
patent: 5289812 (1994-03-01), Trombley et al.
Moulis Thomas N.
Orbital Engine Company (Australia) Pty. Limited
LandOfFree
Fuel system for fuel injected internal combustion engines does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel system for fuel injected internal combustion engines, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel system for fuel injected internal combustion engines will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1362502