Patent ID: 6937931

Claim:
A vehicle control system which has an engine and a hydro-mechanical transmission formed such that power from the engine is transmitted from an input shaft to an output shaft through a mechanical transmission unit and a hydrostatic transmission unit, the vehicle control system comprising: (a) target engine speed altering means for changing, according to an operating amount, a target engine speed set as a target value for the actual speed of the engine; (b) target speed ratio calculating means for calculating a target value for the speed ratio of the hydro-mechanical transmission which target value makes the actual speed of the engine coincident with the target engine speed; (c) hydrostatic transmission unit controlling means for controlling the hydrostatic transmission unit so as to make the actual speed ratio of the hydro-mechanical transmission coincident with the target speed ratio calculated by the target speed ratio calculating means; and (d) engine controlling means for controlling the engine such that if the target engine speed is changed from a first target value to a second target value lower than the first target value by the target engine speed altering means, the output torque of the engine is reduced, while keeping the ratio of the amount of change in the output torque of the engine to the amount of change in the target engine speed constant or substantially constant.