Control System for an Agricultural Vehicle

摘要

A control system for a hydrostatic transmission of an agricultural vehicle such as a combine harvester comprises a variable displacement hydrostatic pump and a hydrostatic motor. The control system comprises means 20 such as a sensor for determining the prevailing transmission ratio and a controller 16 for applying a demand signal to set the desired ratio of the hydrostatic transmission 12. The magnitude of the demand signal applied by the controller 16 to the transmission 12 is limited such that the no-load transmission ratio corresponding to the demand signal does not differ from the prevailing measured transmission ratio by more than a predetermined amount.