Caterpillar has signed a 20-year agreement with BAE Systems to use BAE’s HybriDrive parallel hybrid propulsion system. Under terms of the agreement, BAE will integrate its HybriDrive into the Cat CX family of transmissions as well as establish an aftermarket field services model using Caterpillar’s global service network.

The parallel system, which is in final development, is based on BAE’s HybriDrive series system, currently used in more than 3,800 transit buses worldwide. The system is said to improve fuel economy 30% for heavy-duty truck applications including refuse collection, construction, pickup and delivery, and utility.

“This agreement brings two industry leaders together to provide a product that will surpass marketplace expectations for cost, performance and support,” said Steve Trichka, general manager of HybriDrive Solutions for BAE Systems. “Building upon our initial relationship to develop the parallel hybrid electric system, this supply agreement cements Caterpillar as a key supplier and partner on a system that will lower fuel and ownership costs and emissions for fleet owners.”

The HybriDrive parallel system will integrate with Cat’s “big-bore” and heavy-duty diesel engines.

“Through this alliance, our transmission will become an integral part of BAE Systems’ new HybriDrive parallel system,” said Jeff Pohl, hauling & OEM drivetrains product manager for Caterpillar. “Our driveline expertise, including planetary automatic transmission expertise, combined with BAE Systems’ proven hybrid technology, will result in a seamlessly integrated product that meets performance and efficiency demands of vehicles that operate in diverse duty cycles.”

According to BAE, testing has shown that the system, available for trucks up to 80,000 lbs., performs best on stop-and-go cycles where the average speed is between 5 and 20 mph. Payback occurs in 3 to 5 years, the company said.