초록 ▼

A method of engine starting in a gas turbine engine comprises rotating the engine to provide an air flow into a combustor of the engine and injecting fuel into the combustor at a varying rate until the engine is lighted-off. The varying rate of the fuel flow is a function of time and is represented

A method of engine starting in a gas turbine engine comprises rotating the engine to provide an air flow into a combustor of the engine and injecting fuel into the combustor at a varying rate until the engine is lighted-off. The varying rate of the fuel flow is a function of time and is represented by a curve having at least one high frequency with respect to a light-off time, representing instant changes of the rate for intersecting a light-off zone while reducing a quantity of fuel injected into the combustor. After the light-off occurrence fuel is continuously injected into the combustor to accelerate the engine to a self-sustaining operation condition. This method of the present invention is adapted to find light-off points under various temperature and altitude conditions, thereby advantageously providing a rapid light-off, particularly under cold weather conditions.

대표청구항 ▼

1. A method of engine starting in a gas turbine engine comprising:rotating the engine at an increasing speed as a function of time to accelerate the engine and provide an air flow into a combustor of the engine;injecting fuel into the combustor at a varying rate during the acceleration of the engine

1. A method of engine starting in a gas turbine engine comprising:rotating the engine at an increasing speed as a function of time to accelerate the engine and provide an air flow into a combustor of the engine;injecting fuel into the combustor at a varying rate during the acceleration of the engine until the engine is lighted-off, the varying rate being a function of time and represented by a curve having at least one high frequency with respect to a light-off time, representing instant changes of the rate for intersecting a light-off zone while reducing a quantity of fuel injected into the combustor; and then,continuously injecting fuel into the combustor to accelerate the engine to a self-sustaining operation condition. 2. A method as claimed in claim 1 wherein the curve comprises a low frequency with respect to the light-off time, representing a change trend of the varying rate. 3. A method as claimed in claim 1 wherein the curve has an increasing trend and comprises an oscillatory profile. 4. A method as claimed in claim 1 wherein the curve has an increasing trend and comprises a series of spikes. 5. A method as claimed in claim 1 wherein the curve has an increasing trend and comprises a squared-off wave profile. 6. A method as claimed in claim 1 wherein the curve has an increasing trend and comprises a step profile. 7. A method as claimed in claim 1 further comprising introduction of a predetermined first fuel flow level into the combustor prior to fuel injection at the varying rate. 8. A method as claimed in claim 7 further comprising: selecting a minimum engine speed to begin the introduction of the predetermined first fuel flow level for starting the engine under a variety of altitude and temperature conditions. 9. A method as claimed in claim 8 further comprising:sensing a temperature of the fuel to be injected into the combustor;sensing a temperature of the air flow to be provided into the combustor;sensing a forward flight velocity ram quantity;sensing an ambient air pressure;sensing the varying speed of the engine; andprocessing the sensed data to determine the minimum engine speed for the introduction of the predetermined first fuel flow level. 10. A method as claimed in claim 9 further comprising:measuring a light-off time taken from the beginning of the introduction of the predetermined first fuel flow level, to the occurrence of the light-off; andstoring the measured light-Off time and the sensed data in a database for reference in a future engine starting process when a search shows no data associated with an altitude and temperature condition, similar to a current altitude and temperature condition generated in a previous light-Off process and stored in the database. 11. A method as claimed in claim 10 further comprising:changing a criterion of the minimum engine speed and the predetermined first fuel flow level to reduce the light-off time according to the stored data associated with the similar altitude and temperature condition, when such data is located in the database; andstoring data regarding the changes and the light-off time currently measured, and deleting the previously stored data of the minimum engine speed and the predetermined first fuel flow level and the previously stored light-off time associated with thin similar altitude and temperature condition, when the current light-off time is shorter than the previously stored light-off time. 12. A method as claimed in claim 1 further comprising: sensing a temperature of an exhaust gas flow to determine if the light-off occurs. 13. A method as claimed in claim 1 further comprising: biasing a profile of the curve representing the varying fuel injection rate according to changes in the altitude and temperature conditions. 14. A method as claimed in claim 1 further comprising: changing the predetermined first fuel flow level according to changes in the altitude and temperature conditions.