Manufacturers Expected to Meet Thresholds Via More Consistent Aftertreatment Performance
A graphic for the Volvo Linear Exhaust Aftertreatment System. Volvo already has a leg up on the 2027 GHG standards via the new VNL. (Volvo)
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The Environmental Protection Agency and California Air Resources Board have established that NOx and particulate emissions from diesel trucks have an adverse effect on respiratory and cardiac health.
Since 2010, truck diesels have used exhaust gas recirculation together with selective catalytic reduction requiring the use of diesel exhaust fluid to get rid of most of the NOx in diesel exhaust. At the same time, the diesel particulate filter introduced in 2007, along with improved combustion systems, controlled particulate matter.
The two systems appeared to be extremely effective, but as time went by, regulators discovered deterioration in the performance of both forms of aftertreatment, especially the SCR system, when trucks were crawling along the highway, as happens in heavy traffic. An EPA press release on the 2027 Clean Trucks Plan final rulemaking states, “The final rule … establishes not only new, much more stringent NOx standards compared to today’s standards, but also requires lower NOx emissions over a much wider range of testing conditions.”
RELATED: EPA Sets Strict Emissions Standards for Heavy Trucks
The systems thus far have depended on hot exhaust to work. This means the basic SCR system works well when the engine is under load…
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