Allison Transmission and GILLIG introduce first bus equipped with eGen Flex™ electric hybrid propulsion system

May 9, 2022
The vehicle can travel in electric-only mode for up to 10 miles or 50 minutes, multiple times per route per day.

Allison Transmission and GILLIG unveiled the first bus equipped with the Allison eGen Flex™ electric hybrid propulsion system. The GILLIG bus was displayed at the APTA Mobility Conference. 

The eGen Flex is the next generation of Allison’s H 40 EPTM electric hybrid propulsion system, which has been on the market for nearly 20 years. In addition to the benefits provided by the H 40 EP, such as improving fuel consumption by up to 25 percent versus a conventional diesel bus, the eGen Flex provides new revolutionary capabilities. 

The system can travel in electric-only mode for up to 10 miles or 50 minutes before converting back to diesel propulsion. The electric-only mode can be utilized multiple times per route per day. The system’s geofencing technology eliminates engine emissions and noise while loading and unloading passengers in dense pedestrian areas and in zero-emission zones and bus depots. The eGen Flex also can operate accessories such as air conditioning and electric heat at optimal efficiency with electric power. 

“Allison is thrilled to introduce the first GILLIG bus equipped with the eGen Flex to provide our mutual customers with full electric vehicle capability, while maintaining a diesel engine for added flexibility, effectively serving as a bridge solution to electrification,” Rohan Barua, vice president, North America sales, global channel and aftermarket, Allison Transmission. “This will allow transit fleets to improve fuel economy and reduce CO2 emissions now without the added investment in capital infrastructure.” 

“We’re proud to partner with Allison to offer revolutionary EV capabilities to our transit customers,” added Ben Grunat, vice president, product planning and strategy, GILLIG. “The electric-only mode available on the eGen Flex will enable fleets to save on fuel and reduce their carbon footprint as they navigate the path to zero emissions and full electrification.” 

The Indianapolis Public Transportation Corporation (IndyGo) will be the first transit system to operate the GILLIG buses equipped with the eGen Flex. Three buses will be delivered to IndyGo this month. The delivery and operation of the new buses represents the next step in IndyGo’s efforts to reduce its dependence on fossil fuels and do its part to protect the environment.