Growing up: medium-duty hybrid electric vehicles come of age
Published in: Fleet Equipment
Date: 2/1/2005
By: Skydel, Seth
While hybrid-electric passenger cars have been available in the U.S. since model year 2000, the field of commercial vehicle HEVs has been expanding to include a number of light-duty pickups. In the 2006 to 2008 timeframe, a number of additional HEVs will become available as well, including some medium-duty truck offerings, which are already being tested.
Last March, for example, FedEx Express started using hybrid-electric delivery trucks in Sacramento and New York City, and plans were underway to field them in other metropolitan areas as well. Using Eaton Corporation’s powertrain technology in a Freightliner chassis, the hybrid-electric has a GVW of approximately 16,000 lbs and a cargo capacity of about 670 cubic feet.
According to FedEx Express, operating characteristics of the hybrid trucks are virtually unchanged from conventionally-powered vehicles. A four-cylinder engine replaces the six-cylinder version because of the added power provided by the electric motor, and a particulate trap has been added to further reduce emissions. The vehicles, the company notes, decrease particulate emissions by 96 percent and travel 57 percent farther on a gallon of fuel.
According to the Hybrid Truck Users Forum (H-tuf at www.htuf.org), medium- and heavy-duty hybrid trucks will likely be available in several vehicle classes later in this decade. H-TUF, a national program for fleets, manufacturers and researchers, works to find applications and generate demand for commercial hybrid vehicles. The forum is operated by WestStart-CALSTART (www.weststart.org) and the U.S. Army’s National Automotive Center. During the October 2004 H-TUF National Meeting, several announcements were made highlighting medium-duty truck hybrid systems. Included was the unveiling of Peterbilt Motors Company’s hybrid hydraulic refuse truck using an Eaton drive system, Enova Systems, redesigned hybrid electric Class 7 delivery tractor and International Truck and Engine and Eaton showed a Class 6 HEV beverage truck.
Also announced at H-TUF were plans to deploy hybrid trucks in a national pilot program. Specifically, the forum’s Utility Hybrid Working Group has chosen International Truck and Engine Corporation and Eaton Corporation to manufacture a minimum of 20 diesel-electric hybrid trucks for the program, which will feature an integrated hybrid powertrain solution jointly developed by the two companies. If the pilot program is successful, International is prepared to produce diesel-electric hybrid trucks as early as 2006.
International and Eaton believe that diesel-electric hybrid technology for commercial trucks promises significant benefits for fleets, including a 40 to 60 percent increase in fuel economy and significantly lower emissions.
The powertrain in the pilot program trucks couples an International DT 466 diesel engine with an Eaton hybrid-electric drivetrain, incorporating a transmission, batteries and permanent magnet motor. Power from the engine is converted directly into electrical energy, which then uses the conventional drivetrain to power the truck. Energy stored in the batteries also provides PTO power when the diesel engine is off, and the trucks can use electric energy to power components such as air conditioning, steering and the water pump.
The system recovers kinetic energy during braking and charges the batteries while the truck is slowing down. This provides additional power for acceleration, making the hybrid trucks ideal for city driving with frequent starting and stopping. Additionally, the hybrid trucks used in the pilot program will operate a utility bucket in an electric-only mode, with the engine off, for up to two hours.
While HEVs require the same general maintenance as conventional vehicles, one concern focuses on technician training. Even though computer and hand-held scanners do most HEV system troubleshooting, there is an acknowledged need for technicians with a better understanding of electric and electronic systems. One source of HEV technician training is the Oklahoma Department of Career and Technology Education. Independent training schools are also adding HEV curriculum, and OEMs are making technician-training materials available to fleets.
With all this activity underway, there’s little doubt that hybrid-electric technology will be increasingly available in medium-duty trucks, and ultimately may find its way into heavy-duty models as well. As these vehicles come of age, fleet managers may also want to take some time to familiarize themselves with the technology and begin addressing technician training and infrastructure needs.
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