Achieving ultra-low NOx and meeting full useful life requirement for CARB 2027 NOx and GHG 2027 Phase2 CO2 regulation w/ opposed piston 2-stroke engine and a conventional ATS.

Internal combustion engines are expected to continue to play an important role in the future of transportation, particularly in long haul transit and off-road applications. Substantially reducing criteria emissions of heavy-duty commercial vehicle engines while reducing CO2 is the quickest way for a more sustainable transportation. The opposed-piston (OP) engine developed by Achates Power has demonstrated the ability to meet the most stringent 0.02g/hp-hr ultralow NOx and CO2 emissions requirements at the same time using only a conventional, underfloor aftertreatment system, offering reduced cost, complexity and compliance risk compared to other diesel engines. The present paper focuses on the measurement results of Achates Power heavy-duty engine achieving CARB proposed ultralow NOx emission for 2027 and 2031+full useful requirements while also meeting the EPA GHG Phase 2 limits with a conventional aftertreatment system which was aged to 435k, 600k and 800k equivalent miles. The paper will outline the EPA cycle results at each aging step and challenge of meeting both criteria emissions and CO2 emissions at same time.