Evaluation of the efficiency improvement potential of diesel multiple unit railcars by the use of an electrical power split hybrid drive

Abstract:
This paper discusses an innovative hybrid drive for diesel multiple unit railcars. The new drive aims at reducing fuel consumption as well as enabling an emission-free operation around railway stations and on tunnel sections of non-electrified railways. By using an electrical power split transmission structure, the new drive benefits from the high efficiency of mechanical transmissions and offers the possibility of a continuously variable transmission. Furthermore, the new transmission structure can be switched between a pure electrical and a diesel-powered electrical power split mode. The new hybrid drive is compared to a diesel-electric drive. For this purpose, simulation models are developed and drive cycle simulations are performed. The simulation results indicate fuel savings of up to 32 % for the considered route characteristics and show a decrease of the required electric drive power of 50 %. Keywords: DMU, hybrid drive, electrical power split transmission, fuel consumption, emission- free operation