Emission Standards For Diesel Machinery
Diesel engines have always been efficient and reliable, yet they have also been known in the past for producing exhaust with high levels of particulate matter (PM) and nitrogen oxides (NOx). Over the past 15 years diesel engines have been transformed into one of the cleanest machines available today thanks to emissions regulations.
Tier 4 engine standards are government-mandated reductions in harmful exhaust gases for diesel-powered machines. Tier 4 standards require a significant reduction in emissions, particularly particulate matter (PM) and nitrogen oxides (NOx). PM is the black smoke or soot found in diesel engine exhaust and NOx consists of both nitrogen monoxide and dioxide gasses.
The U.S. Environmental Protection Agency (EPA) first started enforcing diesel exhaust emission limitations on off-road machinery with diesel engines in 1996 and stationary diesel-engine generator machines in 2006.
The first stage of Tier 4 standards began in 2011 with Tier 4 interim and will conclude with Tier 4 Final in 2015.
These regulations have been implemented in a series of steps called Tier levels which have each introduced more strict limitations on carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM) and non-methane hydrocarbons (NMHC).
Machine Manufacturers Response To Emission Standards
Improvements made inside the engine were enough for machine manufacturers to achieve Tier 2 and Tier 3 standards. In fact, in-engine design changes have made off road diesel machinery the most fuel-efficient and perform better than ever before. These changes include:
- High-pressure common-rail fuel injection
- More precise fuel injection timing
- Advanced electronic engine controls
- Advanced turbocharging
Tier 4 standards, however, will require improvements to the exhaust aftermath systems to properly reduce NOx and PM levels.
The most practical and effective aftermath treatment technologies include selective catalytic reduction (SCR) to control NOx and diesel particulate filters (DPF), which capture the remaining particulate matter (PM).
Special Fuel Requirements
Machines that are fully compliant with Tier 4 standards will be required to use ultra low sulfur Fuel (ULSF) as well as CJ-4 low Ash oil. Keep in mind that CJ-4 low Ash oil can be used in all prior tier machines, which means that owners only need to keep one type of oil on hand.