17 February 2005
The US EPA has announced a new partnership with Eaton Corporation and other parties to demonstrate the full hydraulic hybrid vehicle for urban pick-up and delivery fleets—a technology based on a number of EPA hybrid patents. The vehicle will also feature the EPA’s Clean Diesel Combustion engine.
The members contributing to the partnership include EPA, Eaton Corporation—Fluid Power, United Parcel Service (UPS), International Truck and Engine Corporation, US Army—National Automotive Center, and Morgan-Olson. EPA and Eaton will fabricate integrated hydraulic rear-drive for a UPS package vehicle.
The hybrid hydraulic system stores energy in the form of compressed gas (nitrogen), which is transferred between a low and a high pressure tanks (accumulators) by one or more reversible hydraulic pump/motor units. The accumulator and hydraulic pump replace the battery pack and electric generator known from electric hybrids. According to the EPA, the hydraulic system can recover the vehicle braking energy with impressive, up to 82% efficiency. A hydraulic hybrid SUV prototype was showcased by the EPA during the 2004 SAE Congress.
The demonstration UPS package vehicle will include:
- Two power sources to operate the vehicle—the EPA Clean Diesel Combustion engine and hydraulic hybrid components
- Full hydraulic hybrid technology that replaces the conventional drivetrain with a hydraulic drivetrain and eliminates the need for a transmission
- Primary hydraulic components consisting of two hydraulic accumulator vessels, one engine hydraulic pump, and one integrated rear-drive hydraulic pump-motor assembly
In the UPS demonstration vehicle, the EPA targets a 60-70% fuel economy improvement, meeting the 2010 heavy-duty engine NOx standards, and the ability to recoup additional cost for hydraulic hybrid technology in less than 3 years.
Clean Diesel Combustion (CDC) technology is the combination of several improvements in diesel fuel injection system performance, re-optimization and refinement of air management/turbocharging systems, and an improved combustion system. The EPA intends to develop a CDC diesel engine capable of meeting the 2010 NOx standards without NOx aftertreatment. The EPA has signed CDC development agreements with two industrial partners: International and Ford.