Power plants – Combustion products used as motive fluid
Reexamination Certificate
1999-06-02
2001-05-08
Thorpe, Timothy S. (Department: 3746)
Power plants
Combustion products used as motive fluid
C060S039281, C060S039463
Reexamination Certificate
active
06226976
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to gas turbine engine controls, and in particular to fuel control systems and methods for gas turbine engines.
BACKGROUND OF THE INVENTION
The operation of gas turbine engines, whether used on the ground for power generation or in flight for propulsion or secondary power, is controlled by an electronic control unit commonly referred to as an ECU. Incorporated in the ECU are control schedules and control logic for the engine. For example, LaCroix, U.S. Pat. No. 4,337,615 discloses a start control logic that is embodied in the engine's ECU. This start control logic, like other control logic in the ECU, is related to fuel flow to the engine and includes calculating the temperature rise in the combustor of the engine. To determine this temperature rise, the ECU must know the heating value of the fuel with the fuel's lower heating value commonly used. Thus, these types of engine controls are developed on the assumption that the lower heating value of the fuel is known and will remain constant during the life of the engine.
Some gas turbine engines are used as pollution control devices. Such devices are disclosed in Dodge et al, U.S. Pat. No. 5,592,811 and Maese et al, U.S. Pat. No. 5,673,553 in which volatile organic compounds, (VOCs), are burned and destroyed in the combustor. A problem that has arisen with the use of gas turbine engines in this manner, is that the in these applications the constituents of the gas or fuel being burned in the combustor can vary greatly resulting in a large variation in the lower heating value of the fuel. Sometimes the heating values can vary as much as fifty percent. It has been observed that large variations in lower heating value change the performance of the engine and can cause the engine to over speed or under speed at its normal operating condition.
Accordingly, there is a need for an engine control system and method that adjusts for changes in the lower heating value of the fuel.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a control and method that adjusts fuel sensitive schedules in the ECU of a gas turbine engine for variations in the heating value of the fuel being combusted in the engine.
The present invention achieves this object by providing a control and method programmed into the ECU. The control and method includes the steps of calculating an expected fuel flow for a baseline fuel type and an actual fuel flow as the engine is running. A ratio of these two fuel flows is determined and applied to the heating value of a baseline fuel type, which is preprogrammed into the ECU. This results in a scale factor that is then applied to fuel sensitive schedules in the ECU.
REFERENCES:
patent: 4472936 (1984-09-01), Uchiyama et al.
patent: 5555719 (1996-09-01), Rowen et al.
patent: 6082092 (2000-07-01), Vandervort
patent: 56207062 (1983-07-01), None
patent: 59160227 (1986-02-01), None
Scott Michael W.
Zimmerman Jeffrey S.
Allied-Signal Inc.
Desmond, Esq. Robert
Hayes Eric D.
Thorpe Timothy S.
LandOfFree
Variable fuel heating value adaptive control for gas turbine... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Variable fuel heating value adaptive control for gas turbine..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable fuel heating value adaptive control for gas turbine... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521341