Method of selecting a transmission shift schedule

Abstract

A method for selecting a shift schedule for a transmission in a motor vehicle is provided. The method includes the steps of determining whether a signal-to-noise ratio exceeds a threshold and calculating a tractive effort of the motor vehicle. A vehicle mass and a road grade is then estimated from the tractive effort using a recursive least squares estimator with multiple forgetting when the signal-to-noise ratio exceeds the threshold. A vehicle mass is selected and the road grade estimated from the vehicle mass and tractive effort when the signal-to-noise ratio does not exceed the threshold. A shift schedule is then selected based on the vehicle mass and the estimated road grade.

Description

technical field [0001] The present invention relates to transmissions, and more particularly to methods of selecting a transmission shift schedule in a motor vehicle. Background technique [0002] The statements in this section merely provide background information related to the present disclosure which may, but do not necessarily constitute, prior art. [0003] A motor vehicle with an automatic transmission that includes a shift schedule control strategy that functions to determine when the automatic transmission shifts from one gear ratio to another on the basis of a number of factors Compare. These factors typically include, but are not limited to, engine torque, vehicle speed, and accelerator pedal position. Any given shift schedule for a motor vehicle is a balance between fuel economy and performance, and, based on this balance characterizing the shift schedule, the obtained Any given shift schedule is classified as an economical shift schedule or a dynamic shift sc...

AI Technical Summary

Problems solved by technology

However, due to the variability of driving conditions such as road gradient and vehicle parameters (e.g. vehicle mass), it is difficult to automatically determine which shift schedule is required

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