GB1224285A - A combustion engine fuel control device having a hydraulic speed governor - Google Patents

Abstract

1,224,285. Gas turbine engine fuel systems. BENDIX CORP. July 21, 1969 [July 24, 1968], No . 36578/69. Heading F1G. In a fuel control device for a combustion engine comprising a hydraulic speed governor and a fuel metering valve responsive to a control fluidpressure which itself is varied by a lever member subjected to the action of a spring loaded as a function of the position of a control lever and to counteracting forces generated as a function of engine speed and engine acceleration respectively, the counteracting forces are both produced by hydraulic pressure responsive means supplied with distinct hydraulic pressures from an engine speed sensing means and from an engine acceleration sensing means respectively, both sensing means being carried by a rotatable member adapted to be mechanically connected to the engine output shaft. The governor comprises an engine-driven rotor 104 having a diametral bore 108 containing a centrifugal weight 130 which controls the effective flow area of a port 110 to vary, in accordance with engine speed, the hydraulic pressure applied to the interior of a bellows 80. The inertia of a column of liquid contained in a helically wound tube 156 carried by the rotor 104 causes a pressure difference to occur between the two ends of the tube when the engine is accelerated or decelerated. This pressure difference is applied to a diaphragm 88. The bellows 80 and diaphragm 88 control the position of a lever 66, in conjunction with a spring 68. The loading of the spring 68 is controlled through a cam 76 by an engine speed control lever 24. A flapper valve 64 carried by the lever 66 varies the leak-off downstream of a restrictor 56 connected through a line 58 to the discharge side of the fuel pump 34, whereby a piston 48 positions a metering valve 44 controlling the supply of fuel to the engine. The hydraulic fluid for the governor is derived from the fuel pump via a restrictor 126, a line 124, a stationary annular recess 120, ports 116, 118 in the rotor 104 and an annular channel 114 communicating with the port 110. Fuel passing through the port 110 passes via passages 134, a passage 136 and an annular recess 138 to a stationary passage 140 and thence via a passage 142 to the interior of casing 38. The fuel is vented from the casing 38 to the pump inlet via a line 53. The pressure developed intermediate the restrictor 126 and the port 110, i.e., in the channel 114, is communicated to the interior of the bellows 80 via a passage 150, a stationary annular recess 152 and a passage 86. One end 158 of the tube 156 communicates directly with the low-pressure interior of the casing 38, while the other end communicates with the casing interior indirectly via the bore 166 of a rotary spindle 162 and a restrictor 174. A passage 168 leads from the bore 166 to the upper side of the diaphragm 88.