Investigation on control strategy optimisation of harsh transient condition for a marine natural gas engine

Under the dual crisis of energy shortage and environmental pollution, natural gas has become a promising alternative fuel. However, its application in marine engines still has some problems such as knocking and misfire in the cylinder, especially during the harsh transient condition of the main engine, which the transient speed regulation rate should be less than 15%, and the speed recovery time should be less than 15s to meet the corresponding specification requirements. In this paper, the 8M23G marine four-stroke natural gas engine is taken as the research object. And, the harsh transient condition of the engine under two modes of load characteristics and propulsion characteristics was analyzed through experiment and simulation. The results showed that the cooperative control strategy had the best effect, which decreased the Lambda of the engine to less than 3.5. Furthermore, the speed recovery time under load characteristics can be controlled at about 10 s.