What is a Tier IV Diesel Engine?

Tier IV is an emission standard set by the EPA for diesel engines found in industrial and agriculture equipment used in the fields or on the job sites. This emission standard will decrease exhaust emission by 90{fef43dd3ebe491a7a0b77b2f8c85361e365cdac36b5c2305aad1e03c7b03cc05} or more in diesel engines found in equipment like tractors, skid steers, excavators, generators, pumps and more. Furthermore, each engine manufacturer is responsible for developing the technology necessary for achieving these low emissions.

John Deere’s Solution to Tier IV Emissions

The goal is to reduce nitrogen oxides, carbon oxides, and unburnt diesel fuel. The John Deere PowerTech engines achieve this by using exhaust gas recirculation (ERG) strategy to lower NOx levels in combination with a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) to reduce the amount of carbon oxides and unburnt diesel fuel. On larger 9.0L engines they are also using selective catalytic reduction (SCR) system by injecting diesel exhaust fluid (DEF) to convert NOx into harmless chemicals.


  • Quieter Engine Operation
  • More Fuel Efficient
  • Lower Emissions


  • Higher Upfront Equipment Cost
  • More Electronics and Sensors
  • More Fluids to Add (some engines)

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