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Clean Automotive Technology

Hydraulic Hybrid Bicycle Research

Bicycles are an efficient and eco-friendly mode of transportation. They need no fuel, emit no pollution, and are reasonably fast. Driving a car, however, is easier especially when hills are involved and is often chosen over biking. With hydraulic hybrid technology that will no longer be the case.

EPA, working with students from the University of Michigan, developed the Regenerative Brake Launch Assist (RBLA). RBLA configures the hydraulic hybrid technology originally applied in cars and trucks, to fit into the front wheel of a bicycle. This technology could theoretically replace the front tire of virtually any bicycle. This technology reuses braking energy to provide a hydraulic launch. RBLA saves up to 70% of the braking energy. That means braking to a stop from a speed of 20 mph will provide enough energy to launch, from a stand still, at a speed of up to 17 mph.

How it Works

There are four main components in the hydraulic hybrid bike system: the high pressure accumulator, the launch pump, the low pressure reservoir, and the regenerative pump. When the hydraulic brake is squeezed, the regenerative pump switches on and, using the momentum of the bike, pressurizes and transfers fluid from the low pressure reservoir while simultaneously slowing the bike. When the high pressure accumulator is full enough (at around 3000 pounds per square inch [psi]) and the launch is initiated, the pressurized fluid is released into the launch pump to power the front wheel.

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