On-highway diesel engine emission standards came 1987, and did reduce on-highway diesel truck engine efficiency somewhat, but not as much as the 70’s era gasoline engine penalty. Much later off-road diesel emission standards began to come online. This has affected marine engines and stationary engines, such as are used in industrial generator sets and agricultural engines that drive irrigation pumps. Eventually, the name was changed to the more accurate “non-road” to describe everything in the category.
Technology and hardware have continuously improved until it is possible to retrofit emission-reducing equipment to any diesel engine that is in good running condition. Such retrofits are often required by State Air Quality Agencies that now have the oversight of non-road engines such as, for example, are used by drilling rigs.
Government agencies have done a reasonable job of coming to grips with this nearly impossible dilemma. Their job has been to solve the environmental need to reduce air pollution, without completely stopping the commerce and industries that depend on diesel engine power. Government agencies did this by creating the “Tier” system. The Tier system (Tiers 1,2,3, and 4) phased in increasingly stringent emission standards over 3 decades, as a means to make gains without shutting down the economy. Further, they built in a lagging order of requirements which on-highway engines had to meet earlier in the game, and non-road engines had to meet in a later time-frame.
MER Equipment not only sells new emission certified engines, but we also now sell and install exhaust after-treatment equipment. Fortunately, the new emission equipment, often simply replaces the exhaust silencer (muffler).
There are many harmful components to any engines exhaust stream, no matter if it is a gasoline, propane, natural gas or diesel fueled engine. The equipment we sell reduces the regulated components of diesel engine exhaust: CO, HC, PM, and NOX.
CO-Carbon Monoxide
Effectively removed by DOC (oxidation catalyst), flow through filters, and particulate filters.
HC-Hydrocarbon
Effectively removed by DOC, flow through filters, and particulate filters.
PM-Particulate Matter
Effectively removed by DOC, flow through filters, and particulate filters.
NOX-Oxides of Nitrogen
Effectively removed by a combination of cooled EGR (exhaust gas recirculation) and SCR (selective catalytic reduction), both of which are usually OEM supplied.
A note of clarification is needed here: On older engines (lower Tier categories), NOX can be reduced by retrofitting SCR (selective catalytic reduction) equipment. However, air quality agencies seldom require such efforts. New engines (higher Tier categories) now come equipped with the technology to reduce NOX. One last detail: What about all of the unregulated exhaust emissions? How then do we make a difference there? The best answer is to buy the most fuel efficient (think common-rail) engine available, keep it in good running order, and minimize the idle time.
Remember, the best exhaust emission program is to simply burn less fuel.