UPS has announced its purchase of seven hydraulic hybrid vehicles, making them the first package delivery company to employ the unique new hybrids. Unlike a gas/electric hybrid that uses a conventional driveline augmented by an electric motor, the hydraulic hybrid actually does away with the driveline entirely. Instead, engine-driven hydraulic pumps are used to pressurize fluid that's then used to drive the wheels. Storing pressurized fluid allows the engine to shut down during deceleration and stops, and regenerative braking is also employed to pressurize the system. It's a cool arrangement, and one we had nearly forgotten about since its announcement — if you're in Minneapolis, the first market to get the trucks, keep your eye out for one. Full release and system schematic below the jump.

UPS First In Industry to Purchase Hydraulic Hybrid Vehicles UPS is the first company in the package delivery industry to purchase hydraulic hybrid vehicles (HHVs). UPS added seven HHVs to its “green fleet,” which now totals 2,129 low carbon vehicles, including HHVs, electric, hybrid electric, compressed natural gas (CNG), liquefied natural gas, and propane-powered trucks. The first two HHV will be deployed in Minneapolis during the first quarter of 2009, and the additional five HHVs will be deployed later in 2009 and early 2010. HHV Prototype Testing Results in Significant Fuel Economy and Emissions Reduction For decades, UPS has been testing and deploying different types of automotive technology to enhance the environmental performance of our fleet. In June 2006, UPS joined with the U.S. Environmental Protection Agency, Eaton Corporation, the U.S. Army and Navistar International Corp. to form a successful public-private partnership to unveil the world’s first HHV diesel urban delivery vehicle prototype. The partners conducted an 18-month evaluation of the vehicle’s performance and emissions on a UPS delivery route in the Detroit, Michigan area. Results showed that the EPA’s patented hydraulic hybrid diesel technology achieved a 45- to 50-percent improvement in fuel economy and a 30 percent reduction in CO2 emissions compared with traditional diesel-powered vehicles. Fuel economy was increased in three ways: * Vehicle braking energy is recovered that normally is wasted * The engine is operated more efficiently * The engine can be shut off when stopped or decelerating. Eaton, which helped develop and refine the vehicle’s hydraulic hybrid power system, will monitor the new UPS vehicle’s fuel economy performance and emissions in the Minneapolis area. How Hybrid Hydraulic Technology Works A high-efficiency diesel engine is combined with a unique hydraulic propulsion system, replacing the conventional drivetrain and transmission. Hydraulic pumps and hydraulic storage tanks are used to store energy, similar to what is done with electric motors and batteries in hybrid electric vehicles. The EPA estimates that when manufactured in high volume, the added costs of the hybrid components can be recouped in less than three years through lower fuel and brake maintenance costs. UPS Fleet Philosophy UPS is an active participant in advancing and developing future generations of delivery vehicles that significantly reduce fuel consumption and our dependence on fossil fuels – all while remaining an innovative, socially responsible and financially sound corporation.