A Design Approach on Transmission Architecture Fashioned from Merge Gear Shifting Strategy for Improving Driving Comfort in Conventional Passenger Vehicle

Abstract

This paper presents a design approach in improving driving comfort for passenger vehicles, focused on the conventional type being the largest category. Out of several aspects to driving comfort, one is the effort required in gear shifting action. The aim of this work is to achieve this design objective by reducing driver’s involvement and is realized through a two-stage methodology; first, to devise an expedient gear shifting strategy and then to reconfigure the transmission gearbox with a compatible multi-clutch layout by modifying the architecture of the existing dual-clutch based one. A new shifting strategy, based on merging of speed ratio ranges, is brought about by rearranging the connection of gear trains of the existing reference model, and hence, the term merge is used to underscore the strategy and is purposed to address the start-and-stop imposed frequent shifting needs in driving. Functional requirement, imposed by the Merge shifting strategy, needs compliance of certain constraints; one such is mounting of designated gear members on a particular shaft, and the other, torque carrying capacity, provide information on input and controlling parameters, respectively, for design planning based on reverse engineering approach. For this purpose, stick diagrams, depicting power flow, are generated and those complying the criteria are screened out. The proposed and reference models are computationally tested using standard HWFET driving cycle to ascertain shifting instances, and it reflects that the former needs nearly sixty percent less effort to drive, providing improved driving comfort. Therefore, the new design exhibits a sound prospect in the category’s market segment.