Patent GB-1265425-A (GB)
IPC: F02C7/262
Filed: 1970-08-04
Abstract: 1,265,425. Burner control systems. FORD MOTOR CO. Ltd. 4 Aug., 1970 [8 Sept., 1969], No. 37483/70. Heading F4T. [Also in Division Fl]  A control system for a gas. turbine engine includes a flame sensor for sensing when the fuel-air mixture is burning in the combustion chamber and then cutting-off the electrical energy supply to the ignition means. The system also automatically aborts a starting attempt if a flameout occurs before the engine reaches idling speed, and attempts a relight if a flameout occurs at or above idling speed. Only one relighting attempt is permitted in each instance, and the engine is shut down if relighting is unsuccessful. Fig. 1 shows the relays and switches of the control system in the unactuated condition. To start the engine the operator closes switch 18 and momentarily actuates starter button 20 thus causing relay 22 to close switches 22a, 22b, 22c and connect the battery 16 to lead 12, starter motor 26 and time delay relay 28. Closing of switch 22b actuates fuel control relay 30 which in turn closes switches 30a, 30b to respectively maintain actuation of relay 30 and activate fuel control solenoid 50 via switches 32, 38a, 30b and 54a. If a flame appears in the combustion chamber before the delay period of relay 28 expires the resistance of ultra-violet light sensor 66 drops substantially to zero to activate relay 64. The latter opens switch 64a to deactivate time delay relay 28, opens switch 64b, closes switch 64c to maintain actuation of fuel control solenoid 50, opens switch 64d to deactivate the ignition system 60 and extinguish ignition indicator light 58, and closes switch 64e to actuate flame history relay 62. Relay 62 in turn closes switch 62a and also closes switch 62b to lock relay 62 across the source of energy to maintain actuation thereof. As the engine gas generator passes the lower threshold of normal idling speed (i.e. about 47% of maximum speed) speed-responsive switch 24 opens to deactivate relay 22 which opens switches 22a, 22b, 22c and thus disconnects starter motor 26 from battery 16. When the upper threshold of normal idling speed (i.e. about 60% of maximum) is passed, speedresponsive switch 32 opens to complete the normal starting cycle. However, should no flame appear in the combustion chamber before the delay period of relay 28 expires, the latter is actuated to open switch 28a to disconnect starter motor 26 from battery 16 and deactivate relays 22, 30. Relay 30 in turn opens switch 30b to deactivate fuel control solenoid 50 which halts the supply of fuel to the engine. The starting attempt thus is aborted and the circuit returns to the inactive configuration shown, with the exception that manual switch 18 remains closed. Relay 28 holds switch 28a open for sufficient time to permit the engine to coast to rest. The operator can then make another starting, attempt by momentarily closing starter switch 20. If a flame-out occurs before the gas generator speed has reached the threshold of idling speed, the circuit again aborts the starting cycle. The circuit immediately makes one attempt at relighting if a flameout occurs at idling or, if the flameout occurs above idling speed, when the speed has declined to the idling range. If relighting is not successful relighting time delay relay 38 opens switch 38a to shut down the engine. If an excessive engine temperature occurs during operation temperature-sensitive relay 54 is activated to open switch 54a and close 54b to respectively cut-off the fuel supply and illuminate over-temperature light 52. Relay 54 may also open a switch (54c, Fig. 8, not shown) to cut out ignition system 60. If the over-temperature condition is rectified by the time the gas generator speed has dropped to idling, relay 54 is deactivated and a relight is automatically attempted. A continued over-temperature or an unsuccessful relighting attempt shuts down the engine completely. Means for automatically resetting the circuit after a flame-out during the starting cycle may be provided.