Hydraulic Hybrids Offer Promising Alternative For Smaller Vehicles, Too

The US EPA, Eaton Corporation and UPS are working together on testing a hydraulic hybrid delivery truck that could reduce fuel consumption and greenhouse gas emissions. UPS intends to have seven of the experimental vehicles in its fleet by 2010.

The Eaton design borrows technology developed by the US EPA. The parallel hydraulic hybrid system does away with the conventional transmission-based drive train in favor of storing and releasing hydraulic energy, much of which is captured through the vehicle's regenerative braking system. The design still uses a conventional engine to drive hydraulic pumps. These systems have been in use for about a half-century in trucks and other heavy equipment because they can provide full torque at low speeds, a necessity to get the vehicle moving.

Other companies like FedEx and Waste Management are also experimenting with different hydraulic hybrid designs for their vehicles, but Hybra-Drive of Deerfield, MI is hoping to scale the technology to small vehicles, using a series hydraulic hybrid design, which could improve fuel economy in a smaller vehicle by as much as 80 percent. Hybra Drive was recently selected by the US Department of Energy to receive a grant that will allow the company to build three experimental series hydraulic hybrid vehicles for testing by UPS, FedEx and Purolator.

While these vehicles are still much larger than a passenger vehicle, testing of the series hybrid design will provide more definitive information about the overall fuel efficiency of the technology in city driving conditions. The company has already retrofitted a Volkswagen Beetle, a Hummer H1, and a step van with the series hydraulic technology.

Source: GreenTechMedia.com
Photo: UPS