The Ford Escape , Honda Insight, and Toyota Prius are just a few electric hybrid cars on the market. Although these cars are popular in the consumer market, there are limitations to electric hybrid cars when considering scalability. An alternative to the electric hybrid drive is the hydraulic hybrid drive. Hydraulic systems can store and discharge energy more efficiently than electric batteries. Vehicles that require a lot of power are finding hydraulic hybrid drives to be more efficient.
First, Some History…The U. S. Environmental Protection Agency (EPA) has teamed up with such companies as Eaton, Parker Hannifin, Ford, and Chrysler to expand the hydraulic drive field. Back in 2004, the EPA announced that it developed a clean diesel combustion technology for the Ford Expedition, which incorporated an engine design that is simultaneously clean, efficient, and cost-effective. Now, using this concept in conjunction with a full hydraulic drive, this engine is projected to improve the fuel economy of this vehicle by 85% (percentage is higher for city driving).
Read more on hydraulic drives on Hydraulics & Pneumatics.