What is the TIER / STAGE emission standard
The TIER / STAGE standard applies to the emission level of diesel engines. TIER is a standard that originated in North America. Its European counterpart is the STAGE emission standard. Both standards apply to the exhaust emissions of specialized vehicles such as agricultural machinery (tractors, harvesters), construction machinery (excavators, loaders), forestry machinery (harvesters) and other equipment equipped with diesel engines (crushers, sweepers).
HC – hydrocarbons
NOx – nitrogen oxides
PM – solid particles
To achieve the lowest possible NOx emissions, manufacturers use selective catalytic reduction (SCR) catalysts in diesel engines. This system is found in engines that meet Interim Tier4 / Stage IIIB emissions standards upwards.