Abstract: An electrohydraulic proportional actuator for converting an electrical input signal to proportional mechanical output. Fluid power may be derived from pressurized fuel or lubricating oil of an associated engine. The actuator may be used to drive any engine function requiring modulated control. The mechanical output is proportional to the electrical input. The actuator includes mechanical feedback to linearize the response function, thus eliminating the need for closed loop operation of the system in which the actuator is used. Both linear and rotary actuators are disclosed in various embodiments. Each type is capable of operation with either a proportional solenoid and valve or a force rebalance solenoid and valve.

Abstract: A fuel delivery system comprised of a differential having three associated shafts. A first shaft is rotated at a speed responsive to the engine speed and drives the differential. A second shaft is driven by the differential against a variable retarding torque, which torque varies the speed of the second shaft. A third shaft is driven by the differential and drives a variable speed, fixed displacement fuel pump at a speed responsive to the speed of the second shaft combined with the speed of the first shaft.