Strict EPA emission regulations for off-road diesel engines go into effect Jan. 1, 2011, for engines rated 174 hp and above. Farm machinery manufacturers are meeting the new regulations, called Tier 4, with engine designs that drastically reduce smoke and smog. Meeting the new Tier 4 requirements have necessitated some major changes in engine design, particularly for tractors.
Strict EPA emission regulations for off-road diesel engines go into effect Jan. 1, 2011, for engines rated 174 hp and above. Farm machinery manufacturers are meeting the new regulations, called Tier 4, with engine designs that drastically reduce smoke and smog. Meeting the new Tier 4 requirements have necessitated some major changes in engine design, particularly for tractors. 
