GB689350A - Improvements in or relating to control mechanism for prime movers - Google Patents

Abstract

689,350. Fluid-pressure servomotor-control systems. CUMMINS ENGINE CO., Inc. Feb. 19, 1951 [April 24, 1950], No. 3960/51. Class 135. A governing system for a prime mover comprises hydraulic governing means responsive to the speed of the prime mover and auxiliary control means responsive to an operating condition of mechanism driven by the prime mover for modifying the effect of the governing means. The invention is described as applied to a Diesel engine driving mechanism through a torque converter, and the auxiliary control means is responsive to the speed of the output shaft of the torque converter so that when this speed tends to become excessive as a result of a light load, the speed of the engine is reduced. Alternatively, the engine may drive an electric generator or a hydraulic pump, and the auxiliary control means be responsive to the power output of the generator or to the pressure of the pump. The control means may also be responsive to a temperature of the driven mechanism. As shown, a sleeve 33, Fig. 3, driven by the engine carries fly-weights 53 which actuate a valve 42 for controlling the admission of pressure liquid from an annular space 43 to a cylinder 50 containing a piston 51 which, through a lever 62 and a lever and link 64, 65, Fig. 4, loaded by a spring 66, controls the displacement of a fuel injection pump of the kind in which a single pump supplies all the cylinders of the engine through a rotary distributor. A port 95 opening into the cylinder 50 at a position such that it is opened by the piston only at higher engine speeds communicates with a pipe 94 connected to ports 97 of a governor valve 92 responsive to the speed of the output shaft of the torque converter. Excessive speed of that shaft causes the valve 92 to be raised to bleed off liquid from the cylinder 50 to reduce the speed of the engine. A lever 74 adjustably pivoted at 75 and having an adjustable pin and slot connection 73 with the lever 62 varies the loading of a speeder spring 57 in response to movement of the piston 51 to provide "speed droop". A similar arrangement is provided for the speeder spring 91 of the governor valve 92, a connection with the piston 51 being made through the lever 64 and a link 113 connected to a lever 110. A modified piston 51 is described having an axial bore extending from the lower end to an intermediate annular recess which coacts with the bleed port to provide a gradual opening.