EPA Amends Heavy-Duty Diesel Regs for Emergency Vehicles
The changes allow engine manufacturers to request to deploy emission controls or settings to be used only in such vehicles.
An EPA direct final rule published June 8 amends its heavy-duty diesel regulations so engine manufacturers may deploy emission controls or settings to be used only in emergency vehicles such as ambulances and fire trucks. The aim is to allow their engines to perform mission-critical work without the risk of losing power, speed, or torque due to abnormal conditions of the emission control systems, according to the rule.
The existing requirements have spurred the use of diesel particulate filters (called DPFs or soot filters) and other after-treatment systems on most new diesel engines to clean their exhaust.
The rule says EPA received letters from fire chiefs and other stakeholders beginning in October 2011 seeking regulatory action to exempt emergency vehicles from complying with particulate matter emissions standard for heavy-duty diesel engines in model year 2007 and after. Power and speed reductions were occurring on some emergency vehicles.
"Through the comments and letters we have received, as well as our own outreach and data-gathering efforts, we have learned that some emission control systems on fire trucks and ambulances today, in particular, certain applications using diesel particulate filters, are requiring an unexpected amount of operator interventions, and there are current a nontrivial number of emergency vehicles that are electronically programmed to cut power or speed -– even while responding to an emergency -– when certain operational parameters are exceed in relation to the emission control system," EPA states in the rule.