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	Heavy-duty vehicle chassis testing is performed at Southwest Research Institute.
	Transient tests are the most accepted method of testing heavy-duty hybrid electric vehicles.

Heavy-duty vehicle chassis testing is performed at Southwest Research Institute (SwRI) using a 48-inch, twin roll chassis dynamometer. The dynamometer has the ability to simulate vehicle weights up to 120,000 pounds for tandem axle vehicles and 60,000 pounds for single-axle vehicles at a maximum power of 600 horsepower. It is equipped with an electric motor drive for each roll that may operate to test single-axle, tandem-axle, or four-wheel drive vehicles.

Either steady-state or transient tests can be performed on this dynamometer. Steady-state operation includes fixed load or fixed speed tests, which are often useful for power train or cooling studies where a finite number of operating conditions are required.

Transient Tests

• Are the most accepted method to test heavy-duty hybrid electric vehicles (HEVs)

• Are typically used to simulate in-service operation of a vehicle

• Are typically used to quantify exhaust emissions in normal vehicle operation

• Are able to simulate road load, vehicle inertia, and road grade

Route Test Cycles

• Ensure that the vehicle matches the drive cycle distance by continuously modifying the time scale

• Enable matching of the accelerations and/or speeds of the used speed versus time trace

The Dynamometer Test Area

• Has an HVAC system to control the ambient test cell temperature and humidity

• Accommodates vehicles up to 14 ft. high by 14 ft. wide by 60 ft. long with wheelbases up to 45 ft. for single- or tandem-axle vehicles and from 4 ft. to 20 ft. for four-wheel drive vehicles

• Is equipped with a 300-horsepower fan capable of simulating wind speeds up to 100 miles per hour

CFR Title 40 Part 86, Subpart N and Part 1065 compliant, full-scale, constant volume sampling (CVS) system measures exhaust emissions, including:

• Total hydrocarbons

• Oxides of nitrogen

• Particulate matter

• Carbon monoxide

• Carbon dioxide

• Fuel consumption

• Individual hydrocarbon species

• Particulate matter composition

Additional equipment measures unregulated emissions such as:

• Dioxins

• Furans

• Aldehydes

• Metals

• Semi-volatile compounds

• Other toxic compounds in exhaust emissions

Standard data acquisition includes:

• Dynamometer roll load and speed

• All exhaust emissions listed above

• 20 other channels for thermocouples, pressure transducers, other analog signals

• SAE J1939 Controller-Area Network (CAN) data from test vehicle

Other capabilities include:

• In-use unregulated emissions testing

• Customized programs to meet client needs 

For more information about our heavy-duty vehicle chassis testing capabilities, or how you can contract with SwRI, please contact Joseph Anthony at jwanthony@swri.org or (210) 522-3191.

powertraincontroltech.swri.org

| Engine and Vehicle R&D Department | Engine, Emissions & Vehicle Research Division | SwRI Home |

Southwest Research Institute^® (SwRI^®), headquartered in San Antonio, Texas, is a multidisciplinary, independent, nonprofit, applied engineering and physical sciences research and development organization with 11 technical divisions.

December 28, 2012