GB463310A - Improvements in or relating to speed governors for internal combustion engines - Google Patents

Abstract

463,310. Fluid-pressure servomotorcontrol systems. HUNTER, H., and EVANS, A. F. Sept. 24, 1935, No. 26450. [Class 135] In speed - regulating apparatus for internalcombustion engines of the Diesel or semi-Diesel type comprising an engine driven circulating pump 3 taking its supply from the fuel tank and a hydraulic governor 10 which controls a fuel injection pump in accordance with variations in the flow of fuel through the closed circuit containing the pump 3, the fuel injec tion pump is connected to the closed circuit at a point intermediate a control valve 19 adjustable to vary the hydraulic resistance of the circuit and a loaded valve 25 between the control valve and the intake of the pump 3. As shown, the hydraulic governor comprises a piston 10 working in a cylinder 9 integral with the casing of a gear pump 3 which draws its supply through a filter 8 from the lower compartment 6 of a casing 1. The piston 10 is connected to a shaft 15 controlling the delivery of a fuel injection pump, and is loaded by a spring 12. The fuel injection pump draws its supply from an upper compartment 7 the fuel pressure in which is maintained a predetermined amount above that in the compartment 6 by a spring-loaded valve 25. The cylinder is formed with a series of ports 17 controlled by a piston valve 19 and a single port 16 which allows only sufficient fuel to leak from the cylinder when all the ports 17 are closed to maintain the piston at the upper end of the cylinder and so restrict the fuel supply to suit a desired idling speed of the engine. The desired engine speed is increased by raising the valve 19 by rotation of a manually operated shaft 23. The tapered end 20 of the valve gradually opens successive ports 17 so that the resistance to flow from the cylinder 9 decreases and the fuel supply increases due to descent of the piston 10. If then the load on the engine increases say, the engine speed and hence the pump speed fall so that the piston descends to increase the fuel supply and so accelerate the engine to the desired speed. To prevent undue pressure in the cylinder when the engine has a high speed and no load, as, in the case of a road vehicle, when travelling downhill, a spring-loaded relief valve 26 is provided. The stiffer the spring 12 the wider is the divergence of engine speed from the desired value. According to the Provisional Specification, the piston may have a bore co-operating with a fixed tapered rod or may co-operate with a cylinder having tapering grooves and is coupled to the engine throttle valve through a lever with a manuallyadjustable fulcrum.