Effect of multi-speed transmission design on the drive cycle performance of a series-parallel hybrid electric vehicle

For the passenger car sector, original equipment manufacturers (OEMs) homologation activities towards meeting emission legislation standards (set by regulation EC No. 443/2009) have compelled the design of greener transport. The dominant emerging trend of major OEMs has been to produce a hybridised powertrain solution to reduce their overall fleet CO2 targets. Hybrid electric vehicles allow manufacturers to use already available powertrain sub-systems to reduce development cost. Simulation in the design process has now been firmly adopted to reduce the number of prototypes required in the automotive sector as a means of reducing cost. In this study, a quasi-static drive cycle analysis of a multi-speed series-parallel hybrid has been undertaken to demonstrate the drivetrain’s capability to reduce fuel consumption. This configuration maintains the main drivetrain multi-speed design to further optimise fuel economy over the NEDC, and WLTC. Results for WLTC indicated that this optimum hybridised system can improve fuel economy in comparison to the internal combustion engine (ICE) only system by up to 22.1%