Allison Transmission, the largest global manufacturer of medium- and heavy-duty fully automatic transmissions and a supplier of commercial vehicle propulsion solutions, including electric hybrid and fully electric propulsion systems, launched its new zero-emission-vehicle (ZEV)-capable electric hybrid system, the eGen Flex, as the initial product offering under its new Allison eGen brand.

eGen Flex provides bus fleets with full electric engine-off propulsion and accessory power operation capability—suited for zero-emission zones and depot operation, including when approaching, during, and leaving passenger stops for a quieter and healthier environment.

Allison’s new eGen brand represents not only the generation of power, but also the future generations of electric propulsion. The eGen product family will include Allison’s portfolio of electric hybrid and full electric products, including the company’s portfolio of electric axles.

The eGen Flex electric hybrid system includes a new drive unit, inverter and rechargeable energy storage system. The drive unit includes a disconnect clutch that enables engine-off capability. The inverter has an innovative package improvement that reduces its footprint and weight.

The inverter is now water ethylene glycol (WEG) cooled, which eliminates oil lines, decreasing installation complexity, reducing maintenance expense, and increasing uptime.

The energy storage system incorporates the latest Lithium Titanate (LTO) technology, which significantly increases energy density, allows for faster charging and enables pure electric (engine off) extended range capability.

With the launch of eGen Flex Allison will offer two distinct models, eGen Flex and eGen Flex Max.

• eGen Flex will be similar in feature set and capability to the Allison H 40/50 EP electric hybrid propulsion system, but with the package enhancements summarized above.

• eGen Flex Max will offer fully electric propulsion for up to 10 miles, dependent upon duty cycle and accessory load requirements.

eGen Flex and eGen Flex Max will be offered in CertPlus model configurations for sale in California Air Resources Board (CARB)-adopting states.

Similar to the existing H 40/50 EP nomenclature, eGen Flex and eGen Flex Max will also be available in “40” and “50” configurations based on fleet torque requirements.

Increased Accessory Power 2 will be available with eGen Flex, and will be required with eGen Flex Max. This capability electrifies vehicle accessory systems, such as air conditioning and electric heat, allowing those accessories to operate at their optimal efficiency point, and with clean and quiet electric power, thus reducing emissions and strain on the engine, thereby protecting our environment.

Allison is engaged with transit Original Equipment Manufacturers (OEMs) and transit fleets to support a scheduled 2021 commercial release of eGen Flex.

IndyGo, which recently selected Allison’s H 40 EP electric hybrid propulsion solution to power 27 new buses, will be a lead fleet partner for Allison’s revolutionary new electric hybrid product, eGen Flex.

The Allison H 40 EPTM will be paired with the industry benchmark Cummins B6.7 in 24 of the 27 Gillig buses. In addition, IndyGo, Allison and Cummins are partnering to integrate eGen Flex into three of IndyGo’s new buses.

The eGen Flex Max specified by IndyGo will enable pure electric (engine off) operation for up to 10 miles on any route, at any time, without capital infrastructure investment in charging stations.

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 three million metric tons of carbon dioxide from entering the atmosphere.