Chrysler Group LLC and the US Environmental Protection Agency (EPA) are working together to determine the possibility of adapting a hydraulic series hybrid system for application in large passenger cars and light-duty vehicles. The announcement of the partnership was made at the EPA laboratories in Ann Arbor, Mich., following a meeting with Sergio Marchionne, Chrysler Group CEO, and Lisa P. Jackson, Agency Administrator for the EPA.
The hydraulic hybrid system, developed by the EPA’s lab in Ann Arbor (earlier post), is well known and currently used in industrial applications, including large delivery trucks and refuse trucks across the country. The technology has shown substantial increases in fuel economy when compared with traditional powertrains in the same type of vehicles.
Hydraulic hybrid systems consist of two key components: high pressure hydraulic fluid vessels called accumulators, and hydraulic drive pump/motors. The accumulators are used to store pressurized fluid. Acting as a motor, the hydraulic drive uses the pressurized fluid to rotate the wheels. Acting as a pump, the hydraulic drive is used to re-pressurize hydraulic fluid by using the vehicle’s momentum, thereby converting kinetic energy into potential energy.
Working together, both parties hope to reduce the size and complexity of the hybrid system and produce a technology that is sensitive to the needs of drivers for smooth and quiet operation.
The research project will focus on adapting the hydraulic hybrid system to a Chrysler Town & Country minivan equipped with a 2.4-liter, inline four-cylinder gasoline engine. Components of the hydraulic hybrid system include a 117 cc engine pump, a 45 cc drive electric motor and a two-speed automatic transmission. Fluid for the system will be stored in a 14.4-gallon high pressure accumulator.
The system produces power with engine torque driving a hydraulic pump that charges the high pressure accumulator of up to 5,000 psi (34.5 MPa). The high-pressure accumulator delivers the pressure energy to the axle hydraulic motor, giving the vehicle power to drive the wheels. The gas engine will remain off if the accumulator charge is sufficient to drive the motor.
EPA and its partners announced the world’s first series hydraulic hybrid urban delivery vehicle in 2006. (Earlier post.) In 2004, EPA had combined a full series hydraulic hybrid system with a diesel engine in a 2003 Ford Expedition SUV. This vehicle was announced and displayed to the public in 2004 SAE World Congress. The prototype showed an 85% improvement in fuel economy.
Hydraulic hybrid vehicle technology is one more promising path worth pursuing in the effort to reduce our carbon footprint, and we are excited to partner with the EPA to push forward on this track.
In this hydraulic hybrid project, the Chrysler Group and EPA will evaluate and, hopefully, validate fuel-efficiency gains and greenhouse gas reductions. One of the aims of Chrysler Group’s integration efforts will be to meet driver expectations for smooth and quiet operation, so that Americans will want to buy and will enjoy driving vehicles with this technology.—Sergio Marchionne
Chrysler Group also will introduce 150 Ram 1500 trucks with a plug-in hybrid electric system in the coming months as part of a project with the US Department of Transportation.