Gm Global Technolgoy Operations, Inc.

David William Minner

Hualin Tan

Xuefeng Tim Tao

Thomas M Sherman

Richard L Tiberg

Jay Ho

Peter J Morgan

A system according to the principles of the present disclosure includes a longitudinal acceleration estimation module, a vehicle longitudinal acceleration sensor, a road grade estimation module, and an actuator control module. The longitudinal acceleration estimation module estimates a longitudinal acceleration of a vehicle based on at least one of a transmission output speed and a wheel speed. The vehicle longitudinal acceleration sensor measures the longitudinal acceleration of the vehicle. The road grade estimation module estimates a grade of a road on which the vehicle is traveling based on the estimated longitudinal acceleration and the measured longitudinal acceleration. The actuator control module controls an actuator of the vehicle based on the estimated road grade.

System and method for estimating road grade based on an output of a longitudinal acceleration sensor in a vehicle

A method of controlling an automatic transmission connected to an engine in a motor vehicle employs a switch for requesting selection of transmission speed-ratio ranges. According to the method, the switch receives an input signal and generates an output signal having the same duration as the input signal. A controller programmed with an engine threshold speed and a threshold signal duration receives and compares the output signal with the threshold signal duration. The controller also determines a current transmission speed-ratio range and a transmission threshold speed-ratio range that is defined by engine's threshold speed. The controller additionally commands the transmission to change the current speed-ratio range to a neighboring speed-ratio range if the signal duration is less than or equal to the threshold. Furthermore, the controller commands the transmission to change the current speed-ratio range to the threshold speed-ratio range if the signal duration is greater than the threshold.

Control of speed-ratio selection in an automatic transmission

A cruise control system includes a speed difference module that compares a current vehicle speed and a target cruise speed, and a brake module that selectively actuates a brake when the current vehicle speed is greater than the target cruise speed by a predetermined speed difference. A related method is also provided and includes comparing a current vehicle speed and a target cruise speed, and selectively actuating a brake when the current vehicle speed is greater than the target cruise speed by a predetermined speed difference. The method includes selectively actuating the brake based on a negative drive torque of a powerplant. The method also includes determining a desired braking force based on the current vehicle speed and the target cruise speed, and actuating the brake to generate an actual braking force less than or equal to the desired braking force.

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Pinckney, MI, United States of America

David William Minner