Field Experience with Automatic Engine/Transmission Control for a Farm Tractor

ABSTRACT AN automatic system received driver input on desired forward speed, while automatically sensing tractor load in terms of engine rpm decrease. The system then controlled governor setting and transmission ratio with the objective of delivering the desired forward speed while having the engine operate at high torque levels a maximum proportion of the time in order to achieve high fuel efficiency. The system functioned as designed, but no fuel savings or performance increases were found in heavy tillage operations as compared with manual control by skilled operators. Special system characteristics were found necessary to permit satisfactory automatic operation during conventional tillage procedures.