Patent GB-1413215-A (GB)
Title: Gas turbine engine control system
IPC: F02C9/28
Filed: 1973-11-01
Abstract: 1413215 Gas turbine engines; centrifugal and axial-flow compressors FORD MOTOR CO Ltd 1 Nov 1973 [3 Nov 1972] 50768/73 Headings F1C and F1G. A gas turbine engine for a vehicle comprises a turbine 12, 14 and a compressor 16, either of which may be single or multi-stage and of radial or axialflow type, on a single shaft 18 which drives a vehicle via reduction gearing 36, torque converter 40 and gear-box 48. An engine-driven fuel pump 26 supplies fuel to combustion chamber 22 via a fluidic metering device 100, excess fuel being returned to the pump inlet via a path 38. An engine speed sensor 66 supplies a signal to a function generator 64, the output signal of which, representing a desired steady state turbine inlet temperature, is supplied to an electronic comparator 62 which is also fed from a sensor 60 with a signal representing actual turbine temperature. The resultant error signal supplied by the comparator 62 via an amplifier 68 to a solenoid 70 positions a valve 72 to control the supply of hydraulic fluid for changing the angular setting of the stator vanes 54 of the reaction member 50 of the torque converter 40 so as to adjust the speed of the shaft 18 and therefore the turbine temperature. A speed function generator sensing the position of the accelerator pedal 82 supplies a signal representing the desired engine speed to a comparator 86 which is also fed with a signal of actual engine speed from the sensor 66. A comparator 80 is fed with a desired acceleration temperature schedule signal 83 and with a signal of actual turbine temperature from the sensor 60. The error output signals from the comparators 80, 86 are fed to a comparator 88, which transmits the higher of the two signals via an amplifier 90 to a solenoid 92 to control the position of a valve 94 which modulates compressor discharge pressure applied to an inlet port 96, the modulated pressure being applied to the control port 104 of the metering device 100 whereby a variable proportion of the fuel flow from the pump 26 is deflected from the return path 38 to a path 108 leading to the combustion chamber 22. Compressor inlet guide vanes 17 are connected to the accelerator pedal 82 by linkage 122, 114, 112, 110 so that they are pivoted to a progressively more open position as the pedal is depressed, the minimum opening at the idle speed of the pedal being limited by a stop 136. If the engine temperature becomes excessive during idling, a motor 138 connected to the output of the temperature-error amplifier 68 moves the stop 136 to the right to increase the guide vane opening and thereby reduce the temperature. At starting, a solenoid 130 is energized via the ignition switch 134 and a pressure switch 132 and moves a pawl 126 into engagement with ratchet teeth 124 whereby if the accelerator pedal 82 is depressed and released, the guide vanes 17 will be opened and then held open whereby starting is facilitated. When the engine speed approaches the idle value, the pressure switch 132 opens to deenergize the solenoid 130 whereby the guide vanes 17 return to their normal position. An overrunning clutch 51 locks up the turbine and pump of the torque converter if the turbine tends to run  faster than the pump, whereby engine braking is provided.