The Environmental Protection Agency (EPA) announced test the implementation of a hydraulic transmission system associated with an internal combustion engine, supposed to be more economical and less polluting.
Based on EPA's technology group Eaton (Ohio) will replace the mechanical transmission of a UPS carrier vehicle with a device for transferring
power through a hydraulic pressure tank. In practice, the pressure of about 3500 tons per square meter, created by the constant speed rotating diesel engine can drive the rotation of a turbine and thus the wheel - the vehicle speed is controlled by the pressure is released in the turbine. This pressure can be built up, which is to store energy. The principle also has a power recovery during braking. This phenomenon, called "regenerative braking" exists for electric hybrid cars but with an efficiency of at 35 40% against almost 75% announced for the hydraulic system.
Preliminary tests in the laboratory would, according to the EPA, highlighted a potential fuel economy of at 60 70% for non-regular (non constant speed). Field trials are eagerly awaited by the project sponsors, among
which the US Army. But the approach does not seem to be unanimous. Ford has in turn dropped that direction to focus on hybrid vehicles.
NYT 10 / 02 / 05 (Test set on transmission That Could save fuel)