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Engine & Emissions Control Standards

The Environmental Protection Agency (EPA) has set new vehicle emissions standards which will require greater vehicle fuel-efficiency and lower emissions levels. The new standards will take effect in 2009 for passenger cars and light duty trucks and in 2010 for Class 8 heavy duty commercial trucks

Meeting New Emission Control Standards

To date, Selective Catalytic Reduction technology is the only vehicle emissions control technology that has been proven to be capable of meeting these standards. In heavy-duty trucks, SCR will reduce:


When the EPA 2010 emissions standards take effect, no heavy-duty diesel engine can be emitting levels of nitrogen oxide (NOx) higher than .2 g/bhp-hr (grams per brake horsepower-hour), a standard more stringent than any in place in Europe.

Using Diesel Exhaust Fluid to convert NOx emissions into levels of pure nitrogen and water vapor, two natural components of the air we breathe, SCR systems can also be combined with a diesel particulate filter (DPF) to achieve even greater emissions reductions and control.

Other options currently being tested require the use of increased exhaust gas recirculation (EGR), which creates more heat rejection (wasted energy) and increased engine degradation, and results in diesel fuel economy penalties as high as 2% - a significant operational expense, especially for those in the trucking industry.

Progress on emissions controls have been encouraged by more than a decade of policy and oversight by the EPA. These emissions control mandates have brought vehicle emissions to near-zero levels. While the mandates were spaced out to provide time for the development and commercialization of emissions control technologies, they have also created unique and complex challenges to communications, research and development times and purchase planning.

Emissions Reduction History

PM – Particulate Matter
NOx – Nitrogen Oxide
NMHC – Non-Methane Hydro Carbon

Specific to heavy-duty commercial vehicles, new regulations set by the EPA for 2010 trucks introduce very stringent emission standards, as follows:


The PM emission standard took full effect in the 2007 heavy-duty engine model year. The NOx and NMHC standards will be phased in for diesel engines between 2007 and 2010 and beyond.