Sources: Diesel Technology Forum, Washington, D.C.
Four million of the 9.5 million medium and heavy-duty commercial trucks operating in the U.S. are equipped with newer technology engines, according to a Diesel Technology Forum (DTF) analysis of IHS Automotive vehicles in operation statistics. The analysis encompasses model year 2007–2015 Class 3-8 diesel trucks in all 50 states and the District of Columbia.
Beginning in 2007, heavy-duty diesel trucks had to meet Environmental Protection Agency-targeted particulate emissions levels of no more than 0.01 grams per brake horsepower hour (g/HP-hr.). “The U.S. fleet is transitioning to newer clean diesel technology, which means immediate fuel savings, lower greenhouse gas emissions and cleaner air,” says DTF Executive Director Allen Schaeffer. “This newest generation of clean diesel trucks have nitrogen oxides (NOx) emissions that are 99 percent lower than previous generations, along with 98 percent fewer emissions of particulate matter, resulting in significant clean air benefits throughout the U.S.”
“Beyond the clean air benefits, model year 2010 and newer trucks also achieve 3 to 5 percent improvements in fuel economy and lower emissions of greenhouse gases. There are now four states—Indiana, Utah, Oklahoma and Texas—where more than 50 percent of the registered diesel trucks are the newer cleaner [models].”
Diesel engine exhaust treatment systems meeting guidelines for 2007 and 2010 truck model years stem from a December 2000 rule EPA promulgated to reduce emissions from buses and on-road heavy-duty trucks by up to 95 percent, and allowable sulfur levels in diesel fuel by 97 percent. Compliant clean diesel systems rely on efficient engine and combustion systems utilizing advanced fuel-injection, turbocharging and power management strategies, coupled with advanced emissions controls and after-treatment technologies, including particulate filters and selective catalytic reduction devices—all running on ultra-low sulfur diesel fuel.