August 17

The CIMAC Position Paper ‘Gas Engine Aftertreatement Systems’ has been compiled by the CIMAC WG17 'Gas Engines' members and provides an overview regarding the exhaust aftertreatment systems for stationary, 4-stroke natural gas engines. This position paper describes the potential impact of stricter exhaust emission standards on engine performance, engine design and the requirements for exhaust aftertreatment systems for natural gas engines. The paper also aims to compare the characteristics of exhaust emission formation of natural gas engines that are operated in one of two regimes, i.e., learn-burn or stoichiometric.

In addition to the performance comparisons between lean burn and stoichiometric engines the paper also presents a relative costs comparison of different aftertreatment systems for both lean burn and stoichiometric engines.

The following topics are covered in the position paper:

  • Combustion Fundamentals of Natural Gas Engines
  • Exhaust Emissions of Lean Burn and Stoichiometric Engines
  • Aftertreatment for Lean Burn and Stoichiometric Engines
  • Aftertreatment Systems Cost Comparison

For your comments and feedback, please write to

Download Publication [PDF]