Diesel and natural gas dual-fuel RCCI engine performance at high altitude.

This study investigated dual-fuel engine performance at high altitude. The test engine was modified from a high-pressure common-rail diesel engine and fuelled with diesel and natural gas. The impact of fuel substitution rate, which is the most critical calibration parameter of dual-fuel engines, on the fuel economy and emissions was studied. Pilot diesel fuel and natural gas flow rates were optimized to minimize fuel consumption while ensuring good combustion stability, emissions, and durability. The advantages of full-load power capability, fuel consumption, and emissions of the dual-fuel engine were revealed with a comparison to the pure diesel engine. This paper also addresses the performance of the dual-fuel engine at high altitudes and reveals its advantages. With an in-cylinder pressure analysis, the test results showed that the dual-fuel engine could achieve higher brake mean effective pressure (BMEP) in a wide range of engine speed compared to the pure diesel engine. When compared at the same operating condition, the dual-fuel engine generally produced much less fuel consumption and emissions, especially at high loads. [ABSTRACT FROM AUTHOR]