Cummins, TM4 to Develop Efficient Plug-In Hybrid Powertrain


TM4 Inc. and Cummins Inc. have announced a joint effort to develop a plug-in hybrid powertrain for Class 7/8 transit buses that can reduce fuel consumption by at least 50% over conventional hybrid buses.

According to the companies, the project aims to provide transit authorities with a flexible, more efficient drivetrain and a long-range, zero-emission capability for inner-city routes.

Having equipped 5,000 buses in China last year, TM4’s real-road experience will be instrumental in developing an optimized powertrain for plug-in transit buses.

“Today, our customers can buy battery-electric or hybrid buses with limited EV range. Our goal is to offer a system that can achieve 35 km EV range and benefit from the 450 kW fast-charging infrastructure to recharge in less than five minutes,” says Robert Baril, managing director of TM4. “The range extender allows for peace of mind and significant flexibility. We are honored to be partnering with Cummins and hope to bring this product to market in the near future.”

With their expertise in internal combustion engines and related products, Cummins researchers will optimize the powertrain by selecting the engine with the best architecture to use as an electric commercial vehicle range extender, using the engine to manage the charge level of the all-electric-drive battery pack. The range extender will be integrated, using advanced vehicle controls, with the electrified powertrain and other applicable technologies.

“The close integration and control of the electrified powertrain with an appropriately selected engine is critically important to developing a plug-in hybrid electric vehicle system. We believe that through the team’s efforts, we can become a significant player in electrification of commercial vehicles by providing complete systems to benefit our global customers,” says Wayne Eckerle, vice president of Cummins research and technology.

Photo courtesy of CNW Group/TM4 Inc. – The system consists of a gen-set (Cummins’ Euro 2019 B4.5 internal combustion engine, coupled with TM4’s LSG130 electric generator), an external ultrafast charging infrastructure, a power collector, a 111 kWh onboard Li-ion battery, a TM4 SUMO electric motor directly connected to the differential, a small fuel tank, and power electronics.

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