NOx reduction : the Perkins solution

Whilst some manufacturers have opted for the less effective Selective Catalytic Reduction (SCR) technology, Perkins Tier 4 engines use a NOx Reduction System (NRS) which delivers both fuel consumption and emissions reductions over Perkins Tier 3 engines and competitive SCR engines.
How it works

The Perkins NOx Reduction System recirculates exhaust gases to slow down the rate of combustion and ensure the fuel is more fully burnt, to reduce the amount of NOx at source.

In combination with other key Perkins’ technologies (such as the Electronic Control Module and Series Turbocharging), the NRS controls the gas flow rates and air-to-fuel ratios in all engine operating conditions.


  • Optimum fuel consumption
  • Smaller overall engine size
  • No second fluid requirement (required for SCR)
  • No associated pipes and tanks
  • Reduced end-user operating costs

The Perkins Tier 4 range also includes numerous new features, such as:

  • Series turbocharging for increased power density
  • Diesel Particulate Filters (DPFs) for improved response and fuel economy
  • New fuel systems and electronics for precise control

You can discover our technology in more detail by clicking the tabs above.