Torotrak, a British technology company known for its continuously variable transmissions, will deliver a paper at the SAE Commercial Vehicle Congress in Illinois next week revealing a flywheel-based Kinetic energy storage system for buses which is said to recover potential energy from a moving vehicle (during breaking) more efficiently than electrical hybrid systems. According to the paper the Torotrak system, which was originally developed in concert with Williams racing for their Formula-1 team, is a lower cost solution than electrical hybrid systems, in a much smaller package, and is simpler to integrate as a retrofit to existing vehicles.
“Our solution offers a much shorter pay back time on investment and does not reduce the number of passengers that can be carried,” explains Chris Brockbank of Torotrak, co-author of the paper. “It is also a fundamentally more efficient approach as energy remains in the mechanical state; with electrical regeneration there is an efficiency loss at each state change from mechanical to electrical to chemical and back again.”
“There is a surprisingly close match between the energy storage requirements of an urban bus and the current F1 regulations,” Brockbank continues. “This also makes the packaging so much easier than an electrical solution; we can even retro-fit a system without impacting on the passenger space.” Torotrak claims the system offers more than 30 percent fuel saving over the London bus test cycle yet can be packaged around an existing transmission.