Reduced emissions elevated altitude diesel fuel injection...

Details Reduced emissions elevated altitude diesel fuel injection... Reduced emissions elevated altitude diesel fuel injection...

1999-09-07

2001-09-11

Moulis, Thomas N. (Department: 3747)

Internal-combustion engines

Engine speed regulator

Having condition responsive means with engine being part of...

C123S500000, C123S501000

Reexamination Certificate

active

06286480

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates generally to diesel engines and, more particularly, to medium speed diesel engines for operation at high altitudes.
Power is generated in a diesel engine by diffusing and combusting diesel fuel in a plurality of engine cylinders. Liquid fuel is injected into the engine cylinders full of compressed air at high temperature. The fuel is broken up into droplets, which evaporate and mix with the air in the cylinders to form a flammable mixture. Complete and efficient combustion in the cylinders requires full oxidation of fuel though evaporation, species diffusion, and mixing with air, and timely heat release during the combustion process. Thus, the amount of cylinder-charged air, or air to fuel ratio of the mixture, plays an important role in diesel engine fuel-air mixing and combustion, which, in turn affects fuel efficiency and exhaust emissions. This is particularly true for quiescent chamber type medium speed heavy-duty diesel engines where the cylinder air intake swirling is slight, such as locomotive or marine type engines having cylinders with relatively large displacement volumes. The fuel injection timing of medium speed diesel engines operating at full load is typically set so that the actual peak firing pressure in the cylinders is at or below a maximum cylinder filing pressure under normal altitude operation, i.e., at about sea level.
Engine exhaust emissions, including carbon monoxide (CO), particulate matters (PM) and smoke, are generated when the air-fuel mixture is incompletely combusted. When engines are operated at higher altitudes, i.e., at a low barometric pressure, lesser amounts of air are introduced into the cylinders, causing the air-fuel mixing process to be deteriorated relative to lower altitude, higher ambient pressure environments. This combination of factors increases late and incomplete combustion in the engine cylinders which lowers fuel efficiency and increases exhaust emissions of CO, PM, and smoke. The reduced amount of air for the fuel-air mixture combustion, together with the increased late and incomplete combustion, typically leads to reduced peak cylinder firing pressure and increased cylinder exhaust gas temperatures. For engines including a turbocharger, the decreased barometric pressure and the increased exhaust temperature cause an increase in turbocharger speed. This usually requires power deration to prevent turbocharger damage from overheating and excessive speed.
Accordingly, it would be desirable to operate a diesel engine at higher altitudes that avoids the resultant increase in exhaust emissions. Additionally, it would be desirable to operate a diesel engine at higher altitudes with minimal deterioration of engine efficiency, power capacity, and engine performance relative to normal altitude operation.
BRIEF SUMMARY OF THE INVENTION
In an exemplary embodiment of the invention, a fuel injection system for a diesel engine having at least one fuel injection pump and at least one fuel injector connected to at least one engine cylinder includes a fuel injection controller, a throttle position sensor and a barometric pressure sensor. The barometric pressure sensor is in fluid communication with an engine air supply, i.e., the air surrounding the engine, and is connected to the fuel injection controller. The barometric pressure sensor supplies a barometric pressure signal to the fuel injection controller, which then adjusts the fuel injection timing by controlling the fuel injection pump and the fuel injector accordingly to advance or retard fuel injection timing to reduce untimely and incomplete combustion in the engine cylinders. Engine efficiency may therefore be optimized and/or exhaust emissions reduced when the engine is operated at higher altitudes at a desired speed and power determined by a selected throttle position.
The fuel injection controller is an electronic controller, such as a microprocessor having a table, or tables, of predetermined fuel injection timing values that have been found to minimize exhaust emissions while optimizing steady state engine operation under the corresponding barometric pressure without exceeding a maximum peak firing pressure in the engine cylinders. Thus, the engine may be continuously and optimally operated under varying pressure conditions while minimizing exhaust emissions and maintaining optimum engine performance. As exhaust emissions are reduced and combustion in the cylinders is more timely and complete, engine power deration due to turbocharger overspeed is largely avoided.


REFERENCES:
patent: Re. 34803 (1994-12-01), Chasteen
patent: 4469066 (1984-09-01), Yuzawa
patent: 4901701 (1990-02-01), Chasteen
patent: 5284116 (1994-02-01), Richeson, Jr.
patent: 5446665 (1995-08-01), Adrian et al.
patent: 5494018 (1996-02-01), Black et al.
patent: 5630402 (1997-05-01), Devine et al.
patent: 5809954 (1998-09-01), Devine et al.
patent: 5813374 (1998-09-01), Chasteen
patent: 5848582 (1998-12-01), Ehlers et al.

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