Patent ID: 8935068
Filing Date: 2015-01-13
Classification: F16H

Abstract:
1. A method of selecting a gear ratio of a transmission in a motor vehicle to produce an increase in negative input torque, the transmission including a controller and N automatically selectable gear ratios, comprising: measuring a current road grade with a sensing device and communicating the current road grade measurement to the controller; receiving by the controller a signal corresponding to a service brake input from the vehicle; determining by the controller a desired maximum acceleration limit of the vehicle based on the current road grade and service brake input signal; calculating by the controller a predicted vehicle acceleration based on the current road grade and an estimated vehicle mass; determining by the controller a current vehicle acceleration, wherein the current vehicle acceleration is determined by calculating by the controller the current vehicle acceleration or by measuring by the controller a vehicle acceleration through a sensing device; computing by the controller an estimated required tractive braking effort and estimated tractive braking effort for at least one of the N automatically selectable gear ratios of the transmission; and selecting by the controller one gear ratio of the N automatically selectable gear ratios for operation of the transmission based on a comparison of the estimated required tractive braking effort and estimated tractive braking effort.