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Modeling the Effects of Transmission Type, Gear Count and Ratio Spread on Fuel Economy and Performance Using ALPHA (SAE 2016-01-1143)
Citation:
Modeling the Effects of Transmission Type, Gear Count and Ratio Spread on Fuel Economy and Performance Using ALPHA (SAE 2016-01-1143). SAE - SOCIETY OF AUTOMOTIVE ENGINEERS. SAE International, Warrendale, PA, (2016).
Impact/Purpose:
As a result of ALPHA model refinements and in preparation for the mid-term evaluation of the 2017-2025 LD GHG rule, EPA is revalidating the model with newly acquired vehicle data to include more realistic vehicle behavior and now includes internal auditing of all energy flows in the model.
Description:
This paper presents an analysis of the effects of varying the absolute and relative gear ratios of a given transmission on fuel economy and performance, considers alternative methods of selecting absolute gear ratios, examines the effect of alternative engines on the selections of gear ratios and presents an algorithm for automatically determining ALPHAShift parameter sets based on the selected engine and transmission combination.