GB1271656A - Control system for a piston engine petrol injection system - Google Patents

Abstract

1,271,656. Fluid-pressure servomotor systems. JOSEPH LUCAS (INDUSTRIES) Ltd. June 20, 1969 [March 29, 1968], No.15171/68. Heading G3P. [Also in Division F1] In a system for controlling the fuel supply to a petrol injection piston engine, a servo-device 12 includes a piston 16 having a three-dimensional cam surface 30 thereon co-acting with a follower 31 for varying the stroke of a metering shuttle 32. The piston is angularly adjustable via arm 29, rod 26 and coupling 27, by the engine accelerator, and is axially adjustable by hydraulic pressure in accordance with engine speed. An engine-driven water-ring or centrifugal pump 11, which may supply fuel to the distributer (not shown), supplies pressurized fuel to the device 12 through a restrictor 14, the fuel thereafter passing through a variable nozzle 18 in a diaphragm 17 to an outlet 15 leading to the outlet side of a boost pump 10. Thus a change in fuel flow-rate through the nozzle 18 due to a change in engine speed, alters the pressure drop across the nozzle and thereby moves the diaphragm 17. This adjusts the degree of opening of a port 21, through which some of the fuel flows to a drain via a restrictor 23, and results in a pressure change within chamber 24 causing the piston to move to a new equilibrium position. If the pump 11 is of the water-ring type, the return line from outlet 15 may instead communicate with an intermediate pressure tapping thereof and the pump 10 may be switched off by a pressure-sensitive device when the engine speed is sufficient for the pump 11 to generate the required injection pressure.