Internal-combustion engines – Charge forming device – Gaseous fuel and air mixer
Reexamination Certificate
1998-03-30
2001-01-23
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Gaseous fuel and air mixer
C123S681000
Reexamination Certificate
active
06176224
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to a method of operating a internal combustion engine, and particularly to a method of operating an internal combustion engine which uses a low energy gaseous fuel.
BACKGROUND OF THE INVENTION
Low energy gaseous fuels are an abundant source of cheap energy. These gases are released by coal mines and landfills and contain a quantity of hydrocarbon fuel, such as methane. Typically, these gases can contain as much as fifty percent hydrocarbon fuel, but some sources contain as little as thirty percent hydrocarbon fuel.
One use for this low energy gaseous fuel is to power an internal combustion engine. The internal combustion engine can be used to drive a generator to produce electricity. The electricity can then be fed into a power grid of an electric utility company in order to generate revenue, or alternatively the electricity can be fed to devices (e.g. lights, pumps, etc.) located proximate the generator in order to power such devices.
A drawback to using low energy gaseous fuels is that internal combustion engines that have heretofore been designed cannot be reliably run with fuels that have a hydrocarbon fuel content of less than forty five percent. In these engines, to combust a low energy gaseous fuel with a hydrocarbon fuel content of less than forty five percent, it is necessary to add natural gas, which has a higher energy content, to increase the energy content of the gaseous fuel. A disadvantage to adding natural gas to the low energy gaseous fuel is that natural gas is more expensive than the low energy gaseous fuel.
One objective when using an internal combustion engine is to reduce emissions of oxides of nitrogen (NO
x
) during operation thereof. NO
x
is produced when nitrogen and oxygen are combined at the high temperatures associated with combustion. Catalytic converters have been used with various internal combustion engines to control the emissions of NO
x
. A disadvantage to the use of catalytic converters is that catalytic converters cannot satisfactorily reduce emissions produced by internal combustion engines that combust low energy gaseous fuels. However, emissions can be reduced to a satisfactory level by precisely controlling the ratio of air to fuel combusted in the internal combustion engine.
What is needed therefore is an apparatus and method for controlling an internal combustion engine that uses a low energy gaseous fuel which overcomes one or more of the above-mentioned drawbacks.
DISCLOSURE OF THE INVENTION
In accordance with a first embodiment of the present invention, there is provided a method of controlling an internal combustion engine assembly. The internal combustion engine assembly includes an internal combustion engine having an engine inlet and an engine outlet; a mixing chamber having an air inlet, a gaseous fuel inlet, and a fuel-air mixture outlet; a fuel valve which controls the ratio of air-to-gaseous fuel in a fuel-air mixture advanced from the fuel-air mixture outlet of the mixing chamber; and a throttle operable to control flow rate of the fuel-air mixture which is advanced from the fuel-air mixture outlet to the engine inlet. The method includes the step of determining oxygen content of exhaust gases advanced through the engine outlet and generating a oxygen content signal in response thereto. The method further includes the step of determining a load on the internal combustion engine and generating a load signal in response thereto. The method yet further includes the step of adjusting the fuel valve to alter the ratio of air-to-gaseous fuel advanced through the fuel-air mixture outlet of the mixing chamber based on the oxygen content signal and the load signal.
In accordance with a second embodiment of the present invention, there is provided a method of controlling an internal combustion engine assembly. The internal combustion engine assembly includes (i) an internal combustion engine having an engine inlet and an engine outlet; (ii) a mixing chamber having an air inlet, a gaseous fuel inlet, and a fuel-air mixture outlet; (iii) a fuel valve which controls the ratio of air-to-gaseous fuel in a fuel-air mixture advanced from the fuel-air mixture outlet of the mixing chamber; and (iv) a throttle operable to control flow rate of the fuel-air mixture which is advanced from the fuel-air mixture outlet to the engine inlet. The method includes the step of determining oxygen content of exhaust gases advanced through the engine outlet and generating a oxygen content signal in response thereto. The method further includes the step of determining a load on the internal combustion engine and generating a load signal in response thereto. The method still further includes the step of adjusting the fuel valve to alter the ratio of air-to-gaseous fuel advanced through the fuel-air mixture outlet of the mixing chamber based on the oxygen content signal and the load signal. The internal combustion engine assembly further includes an exhaust conduit positioned in fluid communication with the engine outlet, and an oxygen sensor positioned in the exhaust conduit for generating the oxygen content signal. The internal combustion engine assembly further includes a fuel-air mixture conduit which couples the fuel-air mixture outlet to the engine inlet, and a pressure sensor positioned in the fuel-air mixture conduit for generating the load signal.
In accordance with a third embodiment of the present invention, there is provided a internal combustion engine assembly. The internal combustion engine assembly includes (i) an internal combustion engine having an engine inlet and an engine outlet, (ii) a mixing chamber having an air inlet, a fuel inlet, and a fuel-air mixture outlet, (iii) an exhaust conduit positioned in fluid communication with the engine outlet, (iv) an oxygen sensor positioned in the exhaust conduit for generating the oxygen content signal, (v) a fuel-air mixture conduit which couples the fuel-air mixture outlet to the engine inlet, (vi) a pressure sensor positioned in the fuel-air mixture conduit for generating the load signal, (vii) an engine controller which receives the oxygen content signal and the load signal and generates a fuel valve adjustment signal in response thereto, and (viii) a fuel valve which controls the ratio of air-to gaseous-fuel in a fuel-air mixture advanced from the fuel-air mixture outlet of the mixing chamber based on the fuel valve adjustment signal.
REFERENCES:
patent: 4388611 (1983-06-01), Haferd
patent: 4411243 (1983-10-01), Hardenberg et al.
patent: 4492205 (1985-01-01), Jundt et al.
patent: 4528957 (1985-07-01), Jundt et al.
patent: 4617900 (1986-10-01), Kobayashi et al.
patent: 4843558 (1989-06-01), Bergnann et al.
patent: 4993386 (1991-02-01), Ozasa et al.
patent: 5140959 (1992-08-01), Durbin
patent: 5197450 (1993-03-01), Kitajima et al.
patent: 5224347 (1993-07-01), Yakabe et al.
patent: 5226396 (1993-07-01), Bailey
patent: 5239974 (1993-08-01), Ebinger
patent: 5251602 (1993-10-01), Kurihara et al.
patent: 5255657 (1993-10-01), Stellwagen
patent: 5261382 (1993-11-01), Nikolai
patent: 5311849 (1994-05-01), Lambert et al.
patent: 5337722 (1994-08-01), Kurihara et al.
patent: 5341299 (1994-08-01), Stellwagen et al.
patent: 5353765 (1994-10-01), Saikalis et al.
patent: 5413078 (1995-05-01), Mitsunaga et al.
patent: 5426934 (1995-06-01), Hunt et al.
patent: 5465697 (1995-11-01), Hamburg et al.
patent: 5474053 (1995-12-01), Suzuki
patent: 5476085 (1995-12-01), Becker et al.
patent: 5529048 (1996-06-01), Kurihara et al.
patent: 5666923 (1997-09-01), Collier, Jr. et al.
patent: 5692478 (1997-12-01), Nogi et al.
patent: 5703777 (1997-12-01), Buchhop et al.
patent: 5983877 (1999-11-01), Madugula et al.
Bernardi John J.
Staab Richard P.
Walling Dennis
Wu Min
Caterpillar Inc.
Maginot Addison & Moore
Moulis Thomas N.
LandOfFree
Method of operating an internal combustion engine which uses... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of operating an internal combustion engine which uses..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of operating an internal combustion engine which uses... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2450866