Configuration Research of the Multi-Mode Hybrid Electric Vehicles with Two Electric Machines

There are many types of Hybrid Electric Vehicles (HEVs) with two electric machines (EMs) on the market. These powertrains with two EMs is conducive to increasing the operating modes, however, the multiple operating modes are very significant to improving the vehicle dynamics and fuel economy. In order to explore the effect of multiple operating modes and multiple gears of HEVs with two EMs, this research based on the existing vehicle models (Toyota Prius, Honda Accord and Chevrolet Volt), and a powertrain system with multiple gears and multiple operating modes (named “Toyota MMMG”) of the Toyota Company to discuss their acceleration performance and fuel economy. This paper analyzed the acceleration performance of these hybrids at 0–120 km/h via a dynamic programming algorithm and used the Rapid dynamic programming (Rapid-DP) method to evaluate their fuel economy under the four driving cycles (FUDS, HWFET, NEDC, and WLTP). Finally, in order to overcome the drawback of the Toyota MMMG, a new configuration was proposed and discussed in this article. It improves acceleration by 53.9% relative to the Prius.