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


TM4 is a world leader in electric powertrain development and equipped an astonishing 5,000 buses in China last year. TM4’s expertise and real-road experience will be instrumental in developing an optimized powertrain for plug-in transit buses.


“TM4 has always innovated to serve the market needs. Today, our customers can buy battery electric or hybrid buses with limited electric vehicle (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. 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,” said Robert Baril, Managing Director of TM4. 


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,” said Wayne Eckerle, VP, Cummins Research and Technology.


The plug-in hybrid powertrain will be shown for the first time at UITP, taking place in Montreal from May 15 – 17, 2017.