Patent ID: 8639419
Filing Date: 2014-01-28
Classification: B60W,F16H,G16Z,Y10T

Abstract:
1. An agricultural vehicle having a continuously variable transmission for transmitting torque from an engine to drive wheels and auxiliary consumers of the vehicle, a braking system for applying a braking force to the drive wheels, the continuously variable transmission including a hydrostatic transmission having a variable displacement pump and a motor, the vehicle comprising: a controller configured for selecting a transmission ratio of the transmission to maintain a desired speed of the drive wheels or of the engine, the controller configured to receive a signal indicative of an engine applied torque, and a signal to indicate application of wheel brakes, wherein, when the braking system is applied to reduce the speed of the drive wheels, the controller is configured to discontinue setting the transmission ratio in dependence upon the speed of the drive wheels such that pump displacement is not set to zero by the controller when the brakes are applied, and instead the controller varies the displacement of the pump while monitoring the load torque on the transmission, the transmission ratio being set based on the engine applied torque so as to minimize the absolute value of the torque transmitted through the transmission.