GB737179A - Improvements in or relating to fuel systems for internal combustion engines - Google Patents

Abstract

737,179. Gas turbine plant. ROLLSROYCE, Ltd. July 15, 1953 [July 21, 1952], No. 18430/52. Class 110 (3). [Also in Group XXIX] In a control system for the supply of liquid fuel of which the viscosity is a unique function of the density to an internal-combustion engine, such as a speed governor comprising a diaphragm 24 subject to the pressure rise generated by a centrifugal pump 20 in the .rotor of a variable swashplate fuel pump, the diaphragm actuating a leak-off valve 18 which controls the position of a servo-piston 13 controlling the angle of the swashplate, the effect on the system of changes of fuel density is substantially eliminated by a second diaphragm 33 connected by a rod 27 to the diaphragm 24 and subject to a load dependent upon the viscosity of the fuel. A conduit 28 interconnects the inlet and delivery passages 22, 15 of the pump and a relief valve 29 ensures a constant pressure drop across orifices 30, 31 which are respectively a sharp-edged orifice and a viscous restrictor, the latter having laminar flow and, as shown, being of annular form. The pressure drop across the orifice 31 therefore varies with viscosity to act on the diaphragm assembly in opposition to the effect of variations of density of the fuel handled by the centrifugal pump. A restriction 32 limits flow through the relief valve 29. In a modification, the diaphragm 24 is subject to the pressure drop across an orifice in series with an enginedriven fixed-capacity pump instead of to the centrifugal pump pressure, and in a further modification the two diaphragms are interconnected by a spring.,