HORSEPOWER SUMMATION CONTROL FOR VARIABLE DISPLACEMENT PUMPS

摘要

ABSTRACT OF THE DISCLOSURETwo variable displacement pumps each having a horsepower (or torque)control valve a pressure limiting valve, and a displacement feedback valve areinterconnected to provide fluid flow paths from the high pressure zone of one pump tothe low pressure zone of the other pump via the horsepower control valve and thedisplacement feedback valve of the respective pumps and vice versa. When one pumpis utilizing less than one-half of the available engine torque as at deadhead operationor low displacement operation wherein its pressure limiting valve determines themaximum delivery pressure or wherein the pump is in standby operation, itsdisplacement feedback valve will correspondingly increase the back pressure of thehorsepower control valve of the other pump so that the latter may utilize the torquedeficiency of the former to bring the total torque utilization of both pumps to theengine torque limit.