School Buses Target of New Electrified Drivetrain Project

An Adomani electric school bus conversion charges outside in Gilroy, California.

A new heavy-duty electric drivetrain specifically designed for school buses and transit buses is being tested this fall with the promise of increased performance, efficiency, acceleration, gradability and range.

Adomani, a provider of replacement drivetrains to the medium- and heavy-duty commercial vehicle market, announced it is partnering with UQM Technologies to beta test the UQM PowerPhase HD250 Drivetrain with an Eaton two-speed transmission and Pi Innovo Transmission Control Unit for peak and continuous power.

The initial pilot program will deploy this fall with production systems expected early next year.

The companies said the drivetrain allows for better packaging, payload capacity and lower cost when compared to direct or single-speed designs. In addition to the improved performance and efficiency, ADOMANI said it expects to achieve “rapid vehicle deployment in an increasingly competitive market landscape.”

Adomani said the variable nature of the PowerPhase drivetrain allows for the optimization of performance and efficiency characteristics by adjusting transmission shift points, depending on the vehicle load and road conditions. This, the company added, can maintain optimal rpm ranges of the UQM electric propulsion systems.

“This proprietary UQM drivetrain system will make it possible for a smaller electric motor to power larger vehicles, and allow ADOMANI to offer increased vehicle performance in the areas of gradability, acceleration, range, and efficiency,” Adomani added.

Jim Reynolds, CEO of ADOMANI, explained that the key to powertrain development is balancing acceleration and top speed with an efficient powertrain and optimal battery capacity.

“This arrangement with UQM will enable us to improve custom and conversion vehicles with the highest possible overall performance and efficiency, allowing us to deliver substantial savings in overall costs and an increase in the vehicle range, which is very important for fleets that currently rely on diesel,” he added.

UQM CEO Joseph Mitchell said the ability of his company to provide the full drive offers ADOMANI “a fully validated solution that will be more effective from a cost, performance and timing standpoint.”

“Much of our competition in the commercial vehicle market comes from what people refer to as a ‘direct drive solution.’ This is a much larger motor that does not use a transmission and has been the solution of choice for many heavy duty manufacturers due to the lack of a state-of-the-art drivetrain with a transmission,” he commented. “For us to compete head-to-head head with direct drive, and not put the burden on the customer to select and source a transmission, we decided to pursue this strategy to provide the entire system.”