July 17, 2002
Ford prepares demonstration fleet of vans with hydraulic power assist
Dearborn, Michigan – Ford Motor Company announced plans for a demonstration fleet of E550 commercial vans equipped with a promising new hydraulic hybrid powertrain. The vans are expected to be up to one-third more fuel efficient in stop-and-go driving than today’s E550.
The demonstration fleet will be put into service in early 2004, likely in a fleet of delivery vehicles that would accumulate mileage quickly, mostly in stop-and-go duty cycles.
The Ford Hydraulic Power Assist (HPA) system will reduce fuel consumption while increasing vehicle performance. A reversible hydraulic motor and an energy-storage accumulator recover energy normally lost during braking, storing it as hydraulic pressure to be later released to provide a boost for acceleration. Launching a heavy vehicle from a stop requires much more energy than keeping that vehicle in motion. Adding a hydraulic boost allows the vehicle to accelerate much more quickly than the same truck without it, while greatly decreasing fuel consumption and exhaust emissions. Ford first showcased the hydraulic assist technology in a concept truck, the Mighty F350 Tonka, at the North American International Auto Show in January 2002.
Ford research indicates that the installation of a HPA system on a commercial van or medium-duty truck could increase fuel efficiency in stop-and-go driving by 30 to 35 percent and cut exhaust emissions by at least 20 percent.
Acceleration performance would also be greatly improved with the additional torque supplied by the HPA system. Computer modeling tests conducted with an E550 loaded to 19,000 pounds showed a 37 percent improvement in 0-30 mph time of 4.4 seconds vs. 7.0 seconds for the same vehicle without HPA. An even more dramatic improvement in acceleration time would be realized on a steep hill climb. For example, a Ford F350 pickup truck research vehicle equipped with HPA can make it up the 30 percent grade at Ford’s Dearborn Proving Ground in 6.6 seconds, a 52 percent improvement from the 12.6 seconds for the same vehicle climbing the 120-foot hill without HPA boost.
An additional benefit to the Ford HPA powertrain is greatly reduced brake wear. Preliminary testing indicates brake wear would be reduced by more than 70 percent, which would lead to significant operating cost savings for commercial fleet operators.
Ford is partnering with U.S. Environmental Protection Agency (EPA) in developing Hydraulic Hybrid technology. Researchers at the EPA’s Ann Arbor, MI, research facility have developed a composite accumulator tank that is relatively lightweight and extremely durable. The tanks are similar to those currently used for compressed natural gas (which typically have an operating pressure of about 3,500 psi). The EPA-developed accumulator tanks have been strengthened to safely operate at pressures up to 6,000 psi.
Another key partner in the project, Eaton Corporation, is providing HPA system architecture, hardware design and electronic controls expertise.