August 14, 2012
This is the fourth blog post in a four-part series from the John Deere Emissions Hub highlighting key moments in the history of John Deere engines. For more historical context, check out our earlier blog posts in the History of John Deere Engines series: Our Early Engines, Our Diesel Debut and A New Generation of Power.
In the 1990s, the Environmental Protection Agency (EPA) presented off-highway diesel engine manufacturers with what would become a complex challenge: drastically reduce emissions. The first EPA emissions regulations for new off-highway engines above 37 kW (50 hp) began in 1996. Since then, several tiers of increasingly stringent regulations have been phased in. The last regulatory tier — Final Tier 4 — will be fully implemented by 2015.