Patent attributes
A HST system for use in traveling of a vehicle includes a controller that controls a pump regulator that changes a displacement of a pump and a motor regulator that changes a displacement of a motor. The controller determines whether or not a particular downhill travel condition is satisfied based on a result of detection by a vehicle speed detector that detects a vehicle speed of the vehicle and a result of detection by a rotation number detector that detects a number of rotations of an engine per unit time. In a case where a depression amount of an accelerator pedal, which is detected by a depression amount detector, is zero and the particular downhill travel condition is satisfied, the controller controls the motor regulator to increase the displacement of the motor.
