Investigation of Gear Shifts in a Parallel-Series Hybrid Powertrain with Dog Clutches in a Demonstrator Vehicle (Two-Drive-Transmission with Range-Extender, DE-REX): Performing mode changes using form-locking shift elements in a demonstrator vehicle and evaluating shift comfort and shift time

摘要

The "Two-Drive-Transmission with Range-Extender (DE-REX)" is an innovative parallelseries hybrid powertrain concept. The DE-REX concept is characterized by coupling two identical electric motors and an internal combustion engine via an automated transmission with the drive shafts of the vehicle. Simulation based investigations have shown, that the powertrain concept offers potentials in terms of a high energy efficiency and that gear shifts can be performed without interruption of driving force. Form-locking dog clutches are used as shifting elements, so that the synchronization of speeds is performed by speed control of the electric motor and of the internal combustion engine in case of gear shifts and mode changes. In the course of the publically funded project "DE-REX", the electric motors and the transmission were designed, manufactured and set up as entire powertrain with an internal combustion engine at both a powertrain test bench and a demonstrator vehicle. The transmission control was developed in a simulation environment and tested respectively enhanced at the powertrain test bench and in the demonstrator vehicle. In this paper three types of acceleration profiles during gear and mode change are defined and criteria for evaluating the sportiness and shift comfort are presented. A selection of evaluation criteria is applied to measurement data of four chosen mode changes gained using the demonstrator vehicle. The results are discussed and finally, potentials regarding shift time reduction and further improvement of shift comfort are suggested.