Research On Critical Influencing Factors Of Low Temperature Start-up Of Electronic Diesel Engine

The cold starting performance of engine is one important performance index for diesel vehicles,which not only relates to the vehicle work efficiency but also affects other emission indexes,fuel consumption and working life.With the diesel emission rules upgraded and the electronic controlled Euro III engine widely used,customers pay more attention on the cold starting problems,which is mainly reflected in starting difficulty,engine stalling after start etc.Under the condition of low temperature,larger torque is required for the engine crankshaft and the engine speed is high in the minimum ignition,so it is very difficult to start.This paper mainly research the factors influencing cold starting of electronic controlled diesel engine from the four aspects,low pressure fuel system,air intake system,starter and battery matching and oil lubrication.And then we conduct corresponding test to give preliminary solutions.(1)This paper analyzes the main problems low pressure fuel system faced at low temperature.Through the theoretical and field analysis we believe that air going into the fuel pipe and fuel wax precipitation is the two main problems the low pressure oil pipe faced.We also discussed the solutions of adding the functions,e.g.fuel pumping,exhausting the air from the fuel pipe and heating the fuel.Then we conducted specific tests relate to the solutions,after that we discussed the low pressure fuel system's impact on cold starting and analyzed the solutions.(2)This part analyzes the influence of air intake on the starting performance and introduces two preheating types of air intake.We calculate the quantity of heat that required & the preheater device can provide,then we analyze the flame &PTC grill preheating influence on starting through specific experiment.(3)This part analyzes the starter & battery matching effect on the starting performance.Having estimated the matching power between starter and engine,we confirm the battery capacity from the starter power and conduct corresponding experiment to analyze the starter & battery matching effect on the cold starting performance.(4)In this part we analyze the oil preheating(lubrication)influence on the diesel engine cold starting performance from two aspects,the weakness of diesel engine cold staring and the preheating necessity.Through the above analysis and the corresponding experiment,this paper summarizes the major problems of diesel engine under the condition of low temperature,meanwhile we put forward corresponding solutions for each system,which will be validated by experiment if the solution can satisfy the system requirements through theoretical analysis.Thus for each system we put forward solutions to improve the electronic controlled diesel engine cold starting performance.From the point of engineering application,basically the problems of difficult to start the electronically controlled diesel engine under low temperature are solved during early promotion,which has a profound impact on the comprehensive popularization and application of electronic control diesel engine.