This electronic flyer highlights our capabilities and activities in the area of Heavy-Duty Emissions Measurement in High-Altitude Environments. Please sign our guestbook. For additional information, e-mail Daniel Stewart,  Southwest Research Institute.

Heavy-Duty Emissions Measurements in High-Altitude Environments 

As emission regulations become more stringent, even lower limits on pollutants of hydrocarbon, carbon monoxide, oxides of nitrogen, and total particulate are required. In addition to more stringent standards, regulatory groups worldwide share concerns that pollutant limits demonstrated in current prescribed test procedures may be exceeded in day-to-day, real-world applications.

The Environmental Protection Agency has bolstered assurance that emission levels are held in check by introducing "not to exceed (NTE)" limits on pollutant emissions over both the prescribed test procedure used for certification of compliance and over a broad range of environmental conditions where large truck engines operate.

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Truck engine manufacturers are responsible for ensuring that their engines do not exceed EPA emission limits in a variety of environmental conditions

ENVIRONMENT

Environmental conditions of concern combine:

  • 50 – 100 °F operating temperature and
  • 10 – 95 % relative humidity and
  • 29.9 – 24.4 inHg barometric pressure

Although these conditions can be assessed to some degree in the field, engine development and calibration efforts should be performed and validated under tightly controlled conditions, using accurate instrumentation and well-defined engine operation practices.

TEST CELL

The Department of Engine and Emissions Research at Southwest Research Institute has developed a transient-capable test cell that provides a range of environmental conditions for heavy-duty diesel engine products that meet the challenges of stringent emission control. This "Super Cell" has the capacity to test engines from 100 to 750 hp, while applying altitude-like conditions to both engine intake and exhaust during transient and steady-state operation.

The Super Cell uses a full-flow CVS, gaseous emissions bench, and particulate measurement system to provide emissions data compliant with current and 2007+ highway engine regulations as well as current and future non-road engine regulations. Conditions within NTE compliance are readily available with the Super Cell, but altitudes up to 12,000 feet, along with additional variations in temperature and humidity conditions, can be achieved to investigate emission levels and engine performance for engine markets outside the NTE envelope.

The ability to test at low and high altitude using a consistent set of instruments, with the same engine setup and control at the same laboratory location, relieves concern for lab-to-lab variability that can introduce additional uncertainty in gaseous and particulate emissions measurements as well as overall engine performance.

Transient torque map responses of a turbocharged diesel engine for low and high altitude

Snap smoke response with altitude

This brochure was published in April 2005. For more information about heavy-duty emissions measurement in high-altitude environments, contact Daniel Stewart, Engine, Emissions and Vehicle Research Division, Southwest Research Institute, P.O. Drawer 28510, San Antonio, Texas 78228-0510, Phone (210) 522-3657, Fax (210) 522-2019.

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