Study shows significant reductions in real-world heavy-duty diesel emissions from 2010 regulations
17 April 2012
New research from North Carolina State University found that federal requirements governing diesel engines of MY 2010 tractor trailer trucks have resulted in major cuts in real world emissions of particulate matter (PM) and nitrogen oxides (NOx).
Dr. Chris Frey, professor of civil, construction and environmental engineering at NC State and Ph.D. student Gurdas Sandhu used a portable emissions measurement system to sample exhaust from diesel trucks while the trucks were in use on roads and highways.
Frey and Sandhu found that a truck in compliance with the older 1999 standards emitted 110 grams of NOx per gallon of fuel used, and 0.22 grams of PM per gallon of fuel used. A 2010 truck emitted 2 grams of NOx per gallon of fuel—a decrease of 98%. The PM emissions were 95% lower.
The NOx reductions stem from the implementation of exhaust gas recirculation and selective catalytic reduction technologies. The PM reductions are the result of installing diesel particulate filters into the tail pipes of diesel trucks.
The paper, “Real-World Measurement and Evaluation of Heavy Duty Truck Duty Cycles, Fuels, and Emission Control Technologies,” is forthcoming from Transportation Research Record, the journal of the Transportation Research Board (TRB). Sandhu is lead author of the paper. The research was supported by the North Carolina Department of Transportation and the National Science Foundation.
Nice!
Posted by: Peter_XX | 17 April 2012 at 11:36 AM
Simply based on the EPA 1998 and 2010 emissions regulations, NOx should reduce from 4 g/hp-hr to 0.2 g/hp-hr, 2010 MY truck would emit 95% less NOx compared to 1999 MY truck. Shouldn't funding be use on other research which is more meaning????
Posted by: hc | 17 April 2012 at 08:54 PM
This is a validation of the regulation to see if the real world matches the theory.
Posted by: Arne | 18 April 2012 at 01:40 PM
HC, that is a good question and is well answered in part by Anne. To elaborate what she said, the EPA regulation is based on strictly defined duty cycle. A duty cycle is a speed vs time profile. Vehicles almost never experience the same duty cycle in real life. They may come close or be far off. The NOx control device that has been introduced starting from 2010 model years, Selective Catalytic Reduction (SCR), is sensitive to exhaust temperatures and maybe other variables which do no yet fully know. So, in short, a vehicle could meet EPA's regulation under the defined duty cycle but does it meet it under real-life conditions? That is what this news story highlights. But the paper and the research go beyond that. One important conclusion of this study was how to compare on-road real-world emissions such that the findings are robust to cycle-to-cycle variations. For example, if you drove a truck from point A to B and I drove a different truck from point C to D, what method can be used to compare your emission rates with mine. Okay, that is a long post! I encourage you to read the full paper to see why the research dollars are well spent :)
Posted by: Gurdas Sandhu | 19 April 2012 at 07:56 PM