Allison Transmission Holdings Inc. and Cummins Inc. announced that they have received certification from the California Air Resources Board (ARB) to sell the model year 2015 Allison H 40/50 EP™ hybrid propulsion system paired with the Cummins ISB6.7 and ISL9 diesel-electric hybrid engines for transit buses and coaches.

The dual Executive Order (EO) issued by the ARB to both Allison and Cummins allows sales of the Allison H 40/50 EP with the Cummins ISB6.7 or ISL9 diesel-electric hybrid engine, and is valid for 2015 models. The ARB first provided approval in 2014, but the process requires the EO to be reviewed for renewal eligibility on a model year basis.

“We are pleased to remain the first and only hybrid system manufacturer approved for the transit market in California,” said Deborah Gordon, executive director of regulatory issues and hybrid programs for Allison Transmission.

Allison’s H 40/50 EP hybrid propulsion system is used for both straight and articulated transit buses. It has been shown to improve fuel economy up to 25 percent over similar diesel buses. Additionally, its regenerative braking capability can significantly extend the brake change interval by as much as 350 percent.

“Cummins is pleased the hybrid system has received 2015 certification from the ARB as it will provide transit customers another viable solution designed to meet their business needs,” stated Laura Chasse, GM, North American Bus Business.  

The Cummins ISB6.7 and ISL9 diesel-electric hybrid engines feature proven technology designed and developed in-house that is optimized to deliver the efficiency, durability and performance transit bus customers expect. The ISB6.7 diesel-electric hybrid engine is rated at 280 hp (209kW) while the ISL9 diesel-electric hybrid engine is rated at 330 hp (246kW) for the transit bus market.

Since 2003, Allison has delivered over 6,700 hybrid propulsion systems which have accumulated almost 660 million miles, saving nearly 35 million gallons of fuel and preventing 345 metric tons of carbon dioxide from entering the atmosphere.