In the early 2000s, the U.S. Environmental Protection Agency introduced a four-tier system to reduce emissions from diesel engines. Stationary and non-road mobile diesel engines, including generator set engines, are included in the EPA’s emission reduction legislation.
Since 2011, all stationary diesel engines used in non-emergency operations are subject to the same restrictions mobile engines (such as truck, locomotive and marine engines) must comply with. Regulations on emergency backup generators are more lenient. There are no emission standards, but emergency generators cannot run unless power is unavailable, with the exception of testing and maintenance (for no more than 100 hours per year in non-emergency situations).
Why Decrease Diesel Engine Emissions?
The EPA’s updated emission standards are expected to prevent 12,000 premature deaths each year. Diesel emissions are so dangerous because they contain particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC).
Diesel engines are often preferred over gas engines in industrial situations because of their fuel economy (30 to 40% advantage over gasoline), reliability and torque output. Unfortunately, “higher engine efficiency and better fuel economy are associated with higher NOx.”
Diesel Engine Emission Control Technologies
New diesel engines are manufactured to comply with EPA regulations using “combustion chamber design, improved fuel systems, implementation of low-temperature charge air cooling, and special attention to lube oil consumption.”
Businesses rely on heavy-duty diesel engines in trucks, trains, boats, tractors, generators and more. Because of this, technologies tended to focus on “fuel economy, reliability, cost and durability” before the EPA regulations took effect. Many of these engines are still in use and now, they must also comply with EPA regulations. Aftermarket technologies were developed to control emissions, including diesel particulate filters (DPF), diesel oxidation catalysts (DOC), and “emulsified fuels, biodiesels, Fischer-Tropsch (F-T) fuels and any combination of these fuels with regular diesel fuels.”
