Gas turbine starter assist torque control system
AssigneeAllied-Signal Inc.
InventorsRobert E. Wahl, Richard F. Stokes
Life of this patent
Estimating the term…
Abstract
An electronic control system for regulating the amount of torque applied by a starter/generator to a gas turbine engine during startup. The control system senses engine speed, compares the engine's actual acceleration with a predetermined acceleration, and adjusts the torque to the engine so that the engine accelerates along the predetermined schedule. The predetermined schedule is a function of the engine's speed or time, inlet conditions and oil temperature.
Claims6
A method of starting a gas turbine engine along a preselected start schedule comprising the steps of:
- providing a starter/generator for driving said engine;
- sensing engine speed and generating a first signal thereof;
- sensing elapsed time of the engine start;
- producing a second signal, in response to said elapsed time, indicative of a predetermined speed for said engine;
- combining said first and second signals to form an error signal;
- and
- adjusting the torque output of said starter/generator in response to said error signal so that said starter/generator only delivers the torque necessary to keep the engine accelerating along the schedule.
A system for starting a gas turbine engine along a preselected start schedule, comprising:
- a starter/generator drivingly coupled to said engine;
- a sensor that senses the speed of said engine;
- a first signal produced by said sensor;
- a timer for determining elapsed time from the engine start;
- a second signal produced by the system, corresponding to the elapsed time determined by said timer, that is indicative of a predetermined speed for the engine;
- an error signal formed from said first signal and said second signal;
- and
- a controller that adjusts the current flow from the starter/generator to adjust the torque output of said starter/generator based on said error signal, so that said starter/generator only delivers the torque necessary to keep the engine accelerating along the schedule.
A system for controlling the torque applied by a starter/generator to a gas turbine engine during startup, comprising:
- means for sensing the speed of said engine;
- means for measuring the elapsed time of said startup;
- means for establishing a predetermined speed schedule for said engine as a function of said elapsed time;
- means responsive to said speed sensing means for generating a signal indicative of said engine's actual speed;
- means for producing an error signal when said engine's actual speed deviates from said predetermined schedule;
- and
- means responsive to said error signal for adjusting the torque applied to said engine by said starter/generator so that said engine accelerates along said predetermined schedule.
A method for controlling the amount of torque applied by a starter/generator to a gas turbine engine during startup, wherein said engine accelerates along a predetermined schedule, said method comprising the steps of:
- (a) accelerating said engine at a rate of about 3% per second up until said engine reaches a speed of about 15% of its operating speed;
- (b) holding said engine at 15% of its operating speed, while igniting a fuel/air mixture in said engine;
- (c) after ignition of said engine, accelerating said engine at about 1% per second;
- (d) after said engine reaches 60% of its operating speed, shutting down said starter generator;
- and
- (e) accelerating said engine in a self sustaining manner to its operating speed.
Dependencies are inferred from the claim text.