Allison Transmission, Cummins Receive CARB Certification


Allison Transmission Holdings Inc. and Cummins Inc. have received certification from the California Air Resources Board (CARB) for the model-year 2020 Allison Hybrid 40/50 Electric Propulsion (H 40/50 EP) system paired with the Cummins B6.7 and L9 diesel-electric hybrid engines used in transit buses and coaches.

Originally issued by CARB in 2014, the dual executive order (EO) is required to be reviewed for renewed eligibility on a model year basis. The paired Allison electric hybrid propulsion system and Cummins engine is used in both straight and articulated transit buses.

“We appreciate ARB’s continued renewal,” says Barbara Chance, director of mobile source regulatory compliance for Allison Transmission. 

“Allison was the first electric hybrid propulsion system to be certified in California for transit buses and coaches. We look forward to continuing our work with CARB,” she adds.

The Allison H 40/50 EP has been proven to improve fuel economy up to 25% over similar diesel buses. Additionally, its regenerative braking capability can significantly extend the brake change interval by as much as 350%.

The Cummins B6.7 and L9 diesel-electric hybrid engines feature technology designed and developed in-house that is optimized to deliver the efficiency, durability and performance on which transit bus customers depend, notes the company. The B6.7 diesel-electric hybrid engine is rated at 280 hp (209 kW) while the L9 diesel-electric hybrid engine is rated at 330 hp (246 kW) for the transit bus market.

Photo: Allison Transmission’s Bus Series web page

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Stephen Lund
Stephen Lund
2 years ago

Why would they use a diesel engine for this bus? Cummins Westport makes a 6.7L engine that runs on Renewable Natural Gas (RNG), a carbon negative, near zero emission engine to link with the electric portion of the hybrid engine. Diesel is high emission with significant particulate matter damaging the environment. It is essential to replace diesel in heavy duty trucks. RNG is the ONLY carbon negative, near zero emission fuel that is commercially available to replace diesel. Electric transportation is VERY environmentally unfriendly due to the coal and fossil natural gas used to generate electricity not to mention the… Read more »