ANN ARBOR, Mich. - The EPA says it has developed a hybrid powertrain capable of achieving 70 mpg in a mid-sized sedan such as the Ford Taurus.
The car uses a conventional internal combustion engine attached to a pump to compress gaseous nitrogen in high-pressure tanks. Releasing the pressure pushes hydraulic fluid through a hydraulic motor, which turns the wheels.
Ford Motor Co. was sufficiently impressed with the hydraulic hybrid to sign a deal with the EPA last October to continue research. But Ford says the technology is a long way from dealer showrooms.
The test car, admittedly a crude prototype, is noisy. Its tanks, motors and pumps would be difficult to package under the hood, particularly in a small car.
"Ford certainly is serious" about the technology, said John Brevick, a project leader at Ford Research Laboratory. But he acknowledged significant hurdles: "The cost, the package, making it totally transparent to the customer, plus reliability, durability - are all issues that have to be worked out."