Allison Transmission’s new eGen Flex hybrid system

Allison Transmission has 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 fully electric, engine-off propulsion and accessory power operation capability—ideal for zero-emission zones and depot operation. The eGen product family will include Allison’s portfolio of hybrid and fully electric products, including electric axles.

The eGen Flex system features a new drive unit, inverter and battery pack. The drive unit includes a disconnect clutch that enables engine-off capability. The smaller and lighter inverter package, which is now water ethylene glycol (WEG) cooled, eliminates oil lines. The company says the new package decreases installation complexity, reduces maintenance expense and increases uptime. The battery pack incorporates the latest lithium titanate (LTO) technology, which increases energy density, allows for faster charging and enables pure electric (engine-off) extended range capability.

Allison will offer two distinct models: eGen Flex and eGen Flex Max. The eGen Flex will be similar in features and capabilities 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. Both models will be offered in CertPlus configurations for sale in CARB-compliant 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. Allison is engaged with transit OEMs and transit fleets to support a scheduled 2021 commercial release of eGen Flex.

“Allison understands that there is significant interest in electrification,” said Managing Director Branden Harbin. “We also understand that fleets are reluctant to go all-in on electrification at this early stage. That critical feedback from our customers is what inspired Allison to deliver this enhanced capability for coach and transit buses, effectively serving as a bridge solution between conventional fuel and full electric solutions. eGen Flex will enable transit fleets to evaluate electric capability and their electric range needs, while still having the peace of mind of a diesel range extender, whether needed for longer routes, for route flexibility, unplanned congestion on routes, or an inability to recharge due to power grid challenges.”

Source: Allison Transmission