Medium- and Heavy-Duty Diesel Vehicles
For most medium- and heavy-duty applications, diesel vehicles are the norm (in contrast to light-duty applications, where gasoline vehicles dominate). Although medium- and heavy-duty diesel vehicles are not technically "alternative fuel vehicles," they can use alternative fuel and benefit from strategies that reduce fuel use and emissions.
Medium-Duty Vehicles
Medium-duty diesel vehicles serve a wide array of applications. With gross vehicle weight ratings (GVWR) of about 8,500 to 26,000 pounds, they include everything from large pick-up trucks and SUVs, to small school and transit buses, to cargo vans and "short-haul" trucks. They are the backbone of many fleets and consume large quantities of fuel because of intensive use.
Heavy-Duty Vehicles
Heavy-duty diesel vehicles include long-haul trucks, large buses, and other vehicles that are heavier than 26,000 lb GVWR. These vehicles are heavy hitters in the fuel consumption arena.
Biodiesel
Biodiesel-diesel blends can be used in most medium- and heavy-duty diesel vehicles with no engine modification. The most common biodiesel blend is B20, which is 20% biodiesel and 80% conventional diesel. B5 (5% biodiesel, 95% diesel) is also commonly used in fleets. To learn more about this fuel, go to the Biodiesel section or search for biodiesel stations using the Alternative Fueling Station Locator.
Emissions
Currently, most medium- and heavy-duty diesel vehicles are equipped with oxidation catalysts—which reduce carbon monoxide (CO) and hydrocarbon (HC) emissions—and particulate matter (PM) traps, which reduce emissions of PM, CO, and HC. In combination, these devices can decrease emissions of CO by 80%, HC by 90%, and PM by 98%. New emissions control devices soon will be required to meet stringent emissions standards. Learn more about diesel emissions and how technologies such as selective catalytic reduction, Diesel Exhaust Fluid, and NOx adsorbers are controlling them.
Clean Diesel
Ultra-low sulfur diesel (ULSD)—which is called "clean diesel" when used in conjunction with advanced emission control devices—is available at fueling stations nationwide and can be used in any diesel vehicle. This fuel reduces the sulfur content in diesel fuel by 97%. Europe has used ULSD for several years. The United States began its changeover to ULSD in June 2006, after the U.S. Environmental Protection Agency (EPA) mandated that 80% of highway diesel fuel produced or imported contain 15 ppm or less sulfur. For more information, visit the Clean Diesel Fuel Alliance.
In keeping with the EPA's mandate, the U.S. Department of Energy's (DOE) Vehicle Technologies Program focuses on increasing heavy-duty diesel engine efficiency significantly above current levels, as well as addressing efficiency penalties resulting from technologies employed to meet increasingly stringent emissions standards. Research in this area supports the goal stated by the 21st Century Truck Partnership to develop and validate a commercially viable, 50%-efficient, emissions-compliant engine system for Class 7 and 8 highway trucks by 2010. For information on diesel engines, see DOE's Diesel Engines: Just the Basics (PDF 267 KB). Download Adobe Reader.
Idle Reduction
More than 13 million light- and medium-duty trucks use more than 600 million gallons per year of fuel while idling. A typical long-haul tractor-trailer idles 1,830 hours per year, resulting in more than 800 million gallons of annual fuel consumption nationwide. Learn more about Idle Reduction strategies and find Truck Stop Electrification Sites across the country.
Fuel Economy Improvements
Go to the Fuel Economy section to learn how strategies such as low-rolling-resistance tires and aerodynamic options help improve medium- and heavy-duty vehicle fuel economy.