Modified start sequence of a gas turbine engine
First Claim
Patent Images
1. A system for starting a gas turbine engine of an aircraft, the system comprising:
- a pneumatic starter motor;
a discrete starter valve switchable between an on-state and an off-state;
a controller operable to perform a starting sequence for the gas turbine engine, the starting sequence comprising alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed;
an electronic engine control system comprising;
a memory for recording a current heat state of the gas turbine engine at shutdown and for recording a shutdown time of the gas turbine engine; and
a risk model for determining a time period (tmotoring) for motoring the gas turbine engine at a predetermined speed Ntarget wherein the predetermined speed is less than a speed used to start the gas turbine engine and wherein tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to the previous shutdown time.
4 Assignments
0 Petitions
Accused Products
Abstract
A system for starting a gas turbine engine of an aircraft is provided. The system includes a pneumatic starter motor, a discrete starter valve switchable between an on-state and an off-state, and a controller operable to perform a starting sequence for the gas turbine engine. The starting sequence includes alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed.
149 Citations
8 Claims
-
1. A system for starting a gas turbine engine of an aircraft, the system comprising:
-
a pneumatic starter motor; a discrete starter valve switchable between an on-state and an off-state; a controller operable to perform a starting sequence for the gas turbine engine, the starting sequence comprising alternating on and off commands to an electromechanical device coupled to the discrete starter valve to achieve a partially open position of the discrete starter valve to control a flow from a starter air supply to the pneumatic starter motor to drive rotation of a starting spool of the gas turbine engine below an engine idle speed; an electronic engine control system comprising; a memory for recording a current heat state of the gas turbine engine at shutdown and for recording a shutdown time of the gas turbine engine; and a risk model for determining a time period (tmotoring) for motoring the gas turbine engine at a predetermined speed Ntarget wherein the predetermined speed is less than a speed used to start the gas turbine engine and wherein tmotoring is a function of the heat state recorded at engine shutdown and an elapsed time of an engine start request relative to the previous shutdown time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification