Patent GB-1183690-A (GB)
Title: Control System for Gas Turbine/Transmission Powertrain.
IPC: F02C7/36
Filed: 1968-11-25
Abstract: 1,183,690. Hydrodynamic torque converters. FORD MOTOR CO. Ltd. 25 Nov., 1968 [24 Nov., 1967], No. 55729/68. Heading F2D. [Also in Divisions F1 G1 and G3] A gas turbine power plant control system comprises a movable means connected to a reaction member 60, Fig. 1, of a hydrodynamic torque converter 51 driven by the gas turbine power output shaft 18 and control means 84 for controlling the intensity of force means 70 acting on the movable means to move the reaction member to maintain the speed of the gas turbine power output shaft at a predetermined level. The uni-shaft gas turbine 10 drives gearing 36, shaft 34 and the torque converter pump element 52. The turbine member 54 drives a vehicle gear-box 58 and a clutch 61 is arranged between the pump shell 62 and the output shaft 56 to lock up the pump and turbine if the latter tends to run faster than the pump. A belt-driven fuel pump 26 supplies fuel via lines 30, 28 to a fuel nozzle 24, excess fuel being returned to the pump 26 via line 38 under the control of a valve 50. The latter is moved by an actuator 48 controlled by a comparator 42 which receives signals from a temperature probe 44 in the gas turbine inlet section and from an output shaft speed sensor 46. The fuel supply to nozzle 24 is controlled to maintain a desired relationship between turbine temperature and speed. Fluid pressure in a chamber 80 acts on a spring-loaded piston 72 to move the reaction member, the fluid pressure from a pump 82 being controlled by a valve 84 which is moved by the centrifugal action of weights 104, driven by the shaft 18, against a spring 118 which is loaded by the operator throttle pedal 114 acting through a cam 116. The angle of stator blades 64 is automatically varied in accordance with changes in the speed of shaft 18 from the predetermined level according to the setting of the throttle pedal 114. In a modification of Fig. 1 a fluid control of fuel by-pass back to the fuel pump includes a fluid pressure speed signal generator 124, a turbine inlet temperature probe 44<SP>1</SP> and a comparator 42<SP>1</SP> which compares turbine inlet temperature to the set temperature generator signal to give the required fuel by-pass flow in line 38<SP>1</SP>. The shaft 128 of the speed signal generator 46<SP>1</SP> is driven by shaft 18, Fig. 1. At a predetermined low speed piston 132 is seated against passage 136 to block the supply of fuel from pump 26<SP>1</SP> through pressure regulator 144 and bore 140. With increased speed piston 132 maintains passage 136 closed until the pressure build-up in chamber 138 overcomes the combined spring and centrifugal force whereafter the piston 132 assumes an equilibrium position thereby controlling the pressure in line 146 and upper chamber 150 of the set temperature generator 124. The lower chamber 152 is connected by a line 158 to the output of the pressure regulator 144 upstream of an orifice 142. A spring centralized diaphragm 154 controls a valve 162 to achieve a predetermined pressure drop between the lower chamber 152 and line 168 as a function of speed changes, the reduced pressure acting in chamber 202 of the comparator 42<SP>1</SP>. The fluid pressure line 158 is connected to the fuel by-pass line 38<SP>1</SP> and a line 176. The flow through line 176 is controlled by the temperature sensing probe 44<SP>1</SP> having a tubular steel housing 178 loosely enclosing a ceramic rod 180. Valve 182 and rod 180 are biased to an initial position giving a minimum fuel flow through lines 176 and 184. Temperature variations cause differential expansion or contraction of the housing and ceramic rod which controls the flow through valve 182 and thereby the pressure in chamber 206 of the comparator 42<SP>1</SP>. In the comparator, a spring centralized valve 188 is acted on by the speeddependent pressure in chamber 202 and the temperature dependent pressure in chamber 206 and controls the flow of by-pass fuel in line 38<SP>1</SP> in a manner similar to that described in Fig. 1.