| 摘要 |
<p>806,228. Automatic turbo-propeller engine control systems. GENERAL MOTORS CORPORATION. March 15, 1957 [March 26, 1956], No. 8715/57. Class 38 (4). [Also in Group XXXVIII] In a system, electrical signals indicative of output power and temperature are applied to a discriminator which provides an output signal, corresponding to whichever input signal represents the greater departure from a datum, for adjusting the engine fuel valve in accordance with the one of the two parameters which at that moment dictates the lower supply of fuel. Fuel is supplied to an engine E by a pump 13 driven from the engine and metered by a fuel control device 16, which is responsive to the temperature and pressure of incoming air, engine speed and acceleration, and the setting of a datum valve 20. The device 16 has a return pipe 17 to the pump 13 and supplies a 15 per cent excess of fuel to the datum valve, the excess being returned to the pump through a by-pass valve 28 when the valve rod 35 which is driven by servomotor 33 is in its null position. The propeller P is driven through a shaft S and pitch control gear G which is effective in the flight range. The speed of the shaft and the torque transmitted thereby is measured by a pair of toothed wheels 41, 42 and co-operating windings 44, 46, the frequency of the induced voltages indicating speed and the phase displacement between them torque. The output shaft 52 of torque servo 50 adopts an angular position according to torque and is connected to a discriminator 60 together with a shaft 59 which adopts an angular position proportional to the temperature at the turbine inlet measured by a number of thermocouples 54. A potentiometer 70, the wiper 67 of which is driven by the discriminator output shaft 66, forms with a potentiometer 73, the wiper 71 of which is set by control lever 75, a bridge fed by a battery 78 in the input circuit of a transistor or magnetic amplifier 62. The amplifier output controls servomotor 33. The detected speed, torque and temperature are displayed on indicators 110, 120 and 115. The amplifier input circuit includes a switch 90 which is opened outside of the flight range and a switch 95 which is operated when the speed is 10 per cent low. These switches transfer control to a preset potentiometer 99 which includes a rectifier 104 in series with wiper 107 so that control by limiting only is permitted. The speed servo 51 drives also a wiper 87 of a potentiometer 80 which is included in the amplifier input circuit so that when during landing the propeller pitch control reaches its lower limit, resistance is added to the input circuit to increase the motor speed. Specification 723,688, [Group XXXVIII], is referred to.</p> |
