Garbage trucks will be the first commercial hydraulic hybrids on the streets next year. Truck manufacturer Peterbilt is building trucks based on technology developed at the EPA's National Vehicle and Fuel Emissions Laboratory, according to the interesting piece in the Wall Street Journal.
The trucks will get 30 percent better gas mileage by capturing energy from braking and using it to compress nitrogen instead of charging batteries.
A hydraulic system, using pistons to capture the wasted energy by compressing nitrogen gas stored in a tank, can capture as much as 75% of the wasted energy. When the nitrogen is allowed to expand, it pushes hydraulic fluid that helps the engine turn the rear wheels.
The EPA was close to developing an 80 mpg hydraulic hybrid car, but the Bush Administration killed the program in 2001. Thanks W! In 2004, the EPA was working on a hybrid SUV with Ford, which quit to license Toyota's technology. However, the WSJ forgot to mention that a hybrid car developed in the 1970s was killed by the EPA.
So hydraulic hybrid technology may give electric hybrids competition, at least for larger vehicles.
It is interesting that we have the DOE funding hybrid development for energy reasons, and the EPA developing its own technology out of concerns for reducing emissions. We really need to streamline resources and have a single program.
