WinGD X-DF

The WinGD X-DF is a family of two-stroke, low-speed, dual-fuel engines from WinGD (Winterthur Gas & Diesel, the former Wartsila two-stroke business) that burns gas on the lean-burn Otto cycle. Gas is admitted at low pressure, premixed, and lit by a pilot oil injection, so the engine needs no high-pressure gas compressor and meets NOx Tier III in gas mode without after-treatment. The trade-off is methane slip from the lean burn, addressed by the iCER exhaust-recirculation option in the X-DF2.0 generation, which cuts slip up to about 50% and lowers fuel consumption. It contrasts with the high-pressure diesel-cycle MAN ME-GI. X-DF-A is the ammonia member, and X-DF-HP is the high-pressure diesel variant.