| 摘要 |
A transmission ratio control system including an engine having fuel supply means for controlling engine power, a hydrostatic transmission driven by the engine including means for varying transmission ratio, a ratio control valve for controlling the ratio varying means, means for applying a bias to the ratio control valve proportional to engine speed, and means responsive to system pressure in the hydrostatic transmission for applying an opposing bias to the ratio control valve proportional to engine torque. In operation, the fuel supply means calls for a predetermined amount of power to be delivered by the engine and the system pressure in the hydrostatic transmission is utilized and as modified by the transmission ratio to provide an indication of engine torque, with the ratio control valve being responsive to the engine speed and the engine torque to vary the transmission ratio to obtain a desired power/speed curve for operation of the engine. The system also includes a brake valve alternatively operable to deliver a signal simulating an engine torque level to correspond to the desired engine speed. |
