Parker to commercialise series hydraulic hybrid system

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Parker Hannifin Corporation has announced the initial commercial commitment for its new Parker series hydraulic hybrid system that is designed to replace the traditional drive train on delivery vehicles to increase fuel efficiency and reduce carbon emissions.

The commitment comes part of a grant under the United States Department of Energy's Clean Cities program and was funded through the American Recovery and Reinvestment Act. Daimler Trucks North America LLC (DTNA) spearheaded the submittal of these winning applications, which will support the purchase of 638 hybrid and alternative fuel vehicles. Parker is the only supplier of the hydraulic hybrid systems for the vehicles. The systems will be purchased by DTNA subsidiary Freightliner Custom Chassis Corporation and incorporated into delivery vehicle models intended for use by United Parcel Service (UPS).

Don Washkewicz, Chairman, CEO and President of Parker, states: "This is a significant development in the advancement of this new hydraulic hybrid system, one of several technology platforms on which we are currently working. The commercial application of our technology is recognition that our system has demonstrated several unique advantages over electric hybrids including significantly better fuel efficiency. Importantly, with products from Parker divisions across geographies, this system is a shining example of our ability to leverage our existing technologies to build complete systems and address some of the most pressing and current engineering challenges of our time, such as the need to decrease energy consumption and reduce our environmental impact."

Increased fuel economy

Field testing of the system during the past year has indicated that the hydraulic system is capable of generating as much as a 50 to 70 per cent increase in miles per gallon in stop-and-go applications when compared with traditional diesel-powered vehicles with automatic transmissions. Prior to field testing, the system was validated for fuel efficiency by the United States Environmental Protection Agency at its National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan.

Parker's series hydraulic hybrid system is said to be unique in that the engine is not connected to the rear wheels of the vehicle. This de-coupling of the engine from the drive wheels offers several advantages including: the ability to recover and store energy from braking, thus reducing brake wear; an engine management system that optimises the vehicle's engine for reduced fuel consumption; the vehicle can be driven with the engine off, which significantly reduces emissions in depots and at delivery points, contributing to reduced fuel consumption.

Dr Joe Kovach, Group Vice President of Technology and Innovation for Parker's Hydraulics Group, comments: "We are on the cutting edge of advancements in series hydraulic hybrid technology working in close partnership with customers such as Freightliner Customer Chassis Corporation to commercialize new systems. We believe the series hydraulic hybrid technology has application not only in delivery vehicles, but also for yard hostlers and city buses. Additionally, our advanced series hydraulic hybrid system, called RunWise, is currently being field tested in more demanding applications such as with refuse vehicles. This is a technology that holds great promise as a contributor to reduced environmental impact and increased fuel efficiency."

How it works

The Parker series hydraulic hybrid system stores energy recovered during the braking process in an advanced accumulator. The energy stored in the accumulator is then used to accelerate the vehicle on the next launch. Once that energy is depleted, the engine is restarted. Unlike electric-hybrid systems that store energy in a battery, the series hydraulic hybrid can recover and reuse as much as 70 per cent of the energy used from braking that otherwise would be lost (traditional electric systems can recover only 20-25 per cent of brake energy). The system is one of a growing range of technologies Parker is developing to address energy-related challenges, with systems in development for renewable energy applications such as wind, solar and wave; other developments are aimed at making more efficient use of traditional energy sources.

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