GILLIG to offer Allison Transmission’s new ZEV-capable electric hybrid system, eGen Flex


Allison Transmission (Indianapolis, Indiana) in partnership with GILLIG, a leading manufacturer of heavy-duty transit buses in the United States, announced that beginning in 2021, GILLIG will offer Allison’s eGen Flex™ electric hybrid propulsion system.

“GILLIG and Allison have partnered for nearly 50 years to provide the highest-quality buses for our customers and the people they serve,” said  Bill Fay , Vice President of Sales at GILLIG. “Our companies are demonstrating how American ingenuity is supporting safe and clean public transportation, and recycling tax dollars back into our communities.”

The Allison eGen Flex system is capable of improving fuel economy by up to 25 percent versus a conventional clean diesel bus, and has the ability to operate accessories such as air conditioning and electric heat at optimal efficiency with electric power. Moving these accessories to electric power reduces the strain on the engine, reducing fuel consumption and maintenance costs over the vehicle’s lifetime.

The full EV capability of the eGen Flex propulsion system can also eliminate engine emissions and noise while loading and unloading passengers, and while operating in densely populated areas or depots using geo-fencing. The eGen Flex system offers full electric drive capability for up to 10 miles, depending upon duty cycle and accessory load demands.

“GILLIG and Allison have established a joint partnership dedicated to optimized integration and a mutual commitment to innovation,” said  Rohan Barua , Vice President of Sales, North America at Allison. “We are excited to continue our history of innovation with GILLIG through the launch of the eGen Flex propulsion system, which provides our mutual customers full electric operation with engine-off capability, without capital infrastructure investment in charging stations. Through this solution, GILLIG and Allison are able to offer customers full EV capability, while maintaining a diesel engine for added flexibility, effectively serving as a bridge solution to EV. The diesel engine can serve as a range extender, when needed for longer routes or route flexibility due to unplanned congestion or construction on routes.”

GILLIG has received their first order for Allison eGen Flex electric hybrid-equipped buses from IndyGo, the Indianapolis Transportation Corporation.

Since 2003, Allison has delivered more than 9,000 electric hybrid propulsion systems globally. These systems have accumulated nearly 2.6 billion miles, saving more than 305 million gallons of fuel, and preventing 3 million metric tons of carbon dioxide from entering the atmosphere. Allison is excited to take the next leap forward with eGen Flex and GILLIG.

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NTEA Member Directory listing for Allison Transmission

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