船用低速二冲程气体燃料发动机早燃特性研究OA

Pre-ignition is the primary obstacle to the development of marine Otto-cycle low-speed two-stroke gas en-gines.This paper analyzes the causes and main influencing factors of pre-ignition in marine low-speed two-stroke gas en-gines.It systematically summarizes the author's recent research on the mechanism and characteristics of pre-ignition in-duced by cylinder oil auto-ignition.The study reveals how cylinder oil auto-ignites and triggers pre-ignition,along with the key factors and underlying patterns involved.It further clarifies the decisive influence of the premixture's air-fuel equivalence ratio and uniformity,and the size and concentration of cylinder oil droplets on the occurrence of pre-ignition.Based on these findings,a pre-ignition suppression technology was developed and successfully applied in China's first independently developed 某型号 low-speed two-stroke dual-fuel engine.By improving the homogeneity of the premixture and reducing the accumulation of small cylinder oil droplets within the cylinder,combined with exhaust gas recirculation to control in-cylinder temperature and lower oxygen concentration,pre-ignition has been effectively sup-pressed,and the engine's power performance and fuel economy have been enhanced.Under operating conditions with a brake mean effective pressure as high as 1.9 MPa,no pre-ignition occurred in this engine.