GB612624A - Improvements in or relating to fuel supply systems for internal combustion engines - Google Patents

Abstract

612,624. Fluid - pressure servomotors. HOOKER, S. G., and BALLANTYNE, D. H. April 1, 1946, No. 10084. [Class 135] [Also in Group XXVII] In a fuel supply system for an internalcombustion engine comprising two or more pumps having regulating means adjusted by a common hydraulic control, means are provided for isolating one or more regulating means from the common control, whereby one or more pumps are rendered inoperative and the rate of delivery of the others is increased. As applied to a jet-propulsion engine, two swashplate pumps 16, 17 delivering through pipes 31 into a common pipe 28 leading to the engine through a throttle valve 29, are controlled by the pressure of fuel on the opposite sides of pistons 34 connected to the angularly adjustable swash-plates 21. The delivery pressure acting on a piston 39 controls a lever 40 pivoted in a diaphragm 14 and controlling a valve 41 allowing fuel to flow through orifices 36 and pipes 44, the pressure drop across the orifices controlling the pistons 34 and hence the pump deliveries. A capsule 43 adjusts the lever 40 according to altitude and the centrifugal pressure set up by the pump rotors 18 acts on diaphragms 47 which open valves 46 above a certain speed, bleeding fuel through the orifices 36 and reducing the pump deliveries. Closing of a manually-operated valve 49 causes an increase of pressure on the right-hand side of piston 34 of pump 17, increasing its delivery. Hence, if pump 16 should fail or its delivery cease due to sticking open of its valve 46 or the valve 41, the pump 17 will maintain the fuel supply on closing of the valve 49. Alternatively, if the pump 17 fails or its valve 46 sticks open, the drop in pressure in pipe 28 closes the valve 41 which causes the delivery of the pump 16 to be increased. Similarly, if the pipe 44<1> is punctured, closure of the valve 49 increases the delivery of pump 17 and the loss of pressure in the pipe 44 of pump 16 reduces its delivery to zero. Non-return valves may be provided in the pipes 44 to prevent a pump which has failed being rotated by fuel from the other pump. A governor may be fitted to each of the pumps so that when either is supplying the engine on its own, its stroke is automatically adjusted to give the maximum permissible speed of the engine.