Patent GB-766460-A (GB)
Title: Improvements in hydraulic governors
IPC: F02D1/00
Filed: 1954-05-19
Abstract: 766,460. Fluid-pressure servomotor control systems. SEBEM SOC. ANON. May 19, 1954 [May 21, 1953], No. 14729/54. Class 135. An all-speed hydraulic governor for an in. ternal combustion engine with fuel injection of the type comprising a volumetric governor pump, e.g. a gear pump, driven by the injection pump and working in a closed hydraulic circuit includes a governing piston 4, Fig. 1, having a variable area passage S therethrough which simultaneously governs the running condition of the engine as a function of the resisting torque of the engine and the degree of irregularity of the governor. The area of the passage S is varied by levers 14, 15, Fig. 2, which co-operate with a beam 13, Fig. 3, secured to the engine speed-control lever 12. Rotation of the lever 14 rotates a valve plate 6 relative to the piston 4 to vary the area of the passage S, each setting of the lever 12 having a corresponding setting of the valve plate which remains constant throughout the whole governing stroke of the piston 4. Rotation of the lever 15 rotates a slotted member 16 engageable with a button 17 fixed to the piston, so that, depending upon the setting of the lever 12 the angle of the slot relative to the piston axis varies whence the area of the passage S during the governing stroke may decrease, remain constant or increase. At limit engine speed, Fig. 3, the area decreases during the governing stroke, i.e. outward movement of the piston, whilst at engine idling speed it increases. Hence the degree of irregularity of the governor may be varied for different engine speeds. This degree of irregularity may be further varied to suit particular engine requirements by the adjustment of a screw 19 in a slot in the beam 13 and by varying the profile of the lever 15. To limit the degree of irregularity at idling speed a pin 15a on the lever 15 engages an adjustable screw 21, thus preventing the lever from following the beam 13 when the lever 12 is moved from idling position to stop. The outward movement of the piston 4 consequent upon reduced engine load which results in increased engine and governor pump speeds adjusts the fuel rack 2 to reduce the fuel supply to the engine and thus return the engine to its governed speed. To increase the rate of injection for intermediate running conditions when the engine load increases, a spring-loaded stop 28 engageable with an adjustable screw 25 carried by a bell-crank lever 26 is fitted so that additional leftward movement of the fuel rack 2 is permitted depending upon the strength of the spring. To automatically increase the rate of injection on starting, the beam 13 is provided with a stop bolt 22 which when the lever 12 is in engine stop position engages the arm 23 of a two-armed lever 24 which lifts the adjustable screw 25 to disengage it from the spring-loaded stop 28 to allow the rack 2 to move to an overload position when the engine is stopped. This overload starting position may be adjusted by a screw 29. To govern the rate of injection at engine limit speed an adjustable sleeve and fork connection 11, 30 is fitted between the fuel rack 2 and the lever 10 which is operatively connected to the piston 4 and may be adjusted to adjust the injection to correspond to the maximum power of the engine. A spring within the sleeve 11 prevents backlash. A non-return bypass valve 35 is fitted across the delivery channel 3 and from the inlet channel 7 to the governor pump to relieve any excess pressure in the closed hydraulic circuit. An adjustable stop 20 engageable with the beam 13 limits the maximum speed of the engine.