Precise Control of Tractor Engine Speed

ABSTRACT An engine speed control was designed and implemented on a JD 4030 tractor for maintaining a steady engine speed as the tractor was used to perform crop production operations. The controller adjusted the position of the throttle control lever on the fuel injector pump to minimize changes in engine speed which normally occur due to changing load. Tractor engine speed was maintained at a reference speed (rpm) selected by the operator to suit the task being performed. The controller measured the engine speed, evaluated the correction in throttle position, and used a digital linear actuator to implement the correction. Performance tests indicated that for a reference speed of 2000 rpm and an update period of 0.2 s, average engine speed for 4 test runs ranged from 1996 to 1999 rpm under abrupt loading cycles ranging from 17 to 52 kw (load applied with a pto dynamometer). The standard deviation of speed for these runs ranged from 4.5 to 6.6 rpm.