Analysis And Optimization Of Distribution Mechanism Of Marine Diesel Engine

This article mainly study on the valve mechanism of a marine large diameter and low speed dual fuel diesel engine.The valve mechanism is one of the kernel components of diesel engine.Whether the design parameters are appropriate or not will directly determine the fuel efficiency,reliability,vibration and noise of the dual fuel diesel engine.The dual fuel engine can work on two combustion scenarios including: a diesel micro-spraying-igniting system with direct injection of HPG or low-pressure gas injection.In any case,the operation must be excellent,smooth and steady.That present harsher demands to the design of the engine and the valve mechanism.This article makes analysis of valve mechanism from different views that purpose to improve the efficiency of the engine.On the basis of the analysis,the cam profile is developed.The article mainly includes following contents:Firstly,based on multi-mass dynamics and multi-flexible dynamics,a dynamic model of the valve mechanism is established.An analysis is carried out,to explore the impact on dynamic effects by setting different parameters.Secondly,based on the different failure modes that often occur in valve mechanism,the failure mechanism is studied.From the perspective of part design,the influence factors leading to contact fatigue failure are given in combination with the material matching method,and the dangerous point is given in conjunction with the dynamic effects.Thirdly,the oil film thickness distribution of the cam-rollers follower mechanism is computed by using of thermal EHL;determine the lubricating state by the film thickness ratio that relates to the surface morphology;according to the Archard wear model,derive a formula for calculating the wear,so as to achieve the prediction of the life of the cam-roller mechanism.Finally,by analyzing and establishing constraint model of contact stress,fullness coefficient,dynamic characters of the cam profile and other parts,the performance and adaptability of the dual fuel diesel valve train are developed.