Hyliion, a startup that converts tractor-trailers to hybrids using a proprietary slide-in intelligent electric drive axle with regenerative braking power, has closed its latest investment round to drive production.

The latest funding round saw a respectable infusion of money to keep the vision going from Sumitomo Corporation of Americas and Axioma Ventures. Specifically, the Series A investment round generated $21 million, which will be used to fund its product and product line expansion. Sumitomo Corporation of Americas has previously made investments in automotive technology, bankrolling Transfix, Inc. and Veritread, an on-demand trucking freight brokerage and construction equipment marketplace, respectively.

“For years, we have invested alongside successful transportation and construction-related businesses throughout the United States,” said Sam Kato, senior vice president and general manager of the Auto and Aerospace Group at Sumitomo Corporation of Americas. “We believe that the technology Hyliion is bringing to this marketplace will not only be attractive to long-haulers seeking to reduce fuel consumption and expenses – but will also make a positive global impact.”

Started by former race car driver Thomas Healy, Hyliion was initially developed as a prototype during his tenure as a Carnegie Mellon University engineering student. Healy first saw the opportunity when as a youth he had observed tractor trailers carrying race cars and realized this fuel-intensive market was under-served by hybridization.

Hyliion’s technology is not an actual tractor-trailer, but a slide-in intelligence electric drive axle that can be applied to tractor-trailers as a new installation or retrofitted to existing vehicles.

Specifically, its hybrid electric system promises to cut fuel costs and emissions by up to 30 percent on the back of three main features: a hybrid engine, an auxiliary power unit to optimize engine idling, and aerodynamic improvements. Hyliion’s website statistics claims its product is compatible with approximately 6 million trailers in the U.S. contributing to $29,000 in annual fuel savings per trailer.