The Design Of Charge Air Pressure Control And Monitoring Safety System For Marine Diesel Engine

Marine diesel engine is a kind of complex thermal power equipment.As the most important power source of offshore and ocean ships,it is also the main equipment of energy consumption,main source of the air pollution as well as the main cause of machine failure during the process of the navigation.In order to promote energy conservation and reduce emission,cut down operating costs and improve the safety level while operating,modern Marine diesel engine technology takes the following aspects as the ultimate goals: to reduce fuel cost,to reduce the pollutant while operating and to further devoelop the convenience and safety of the engine.In this paper,the research object is the L28/32 H Marine medium-speed diesel engine designed and developed by MAN-ES in Germany in the 1980 s.Under the premise of not changing the basic design of the original diesel engine,the advanced charge air pressure control and monitoring safety technology is used to optimize the perfoemance of the diesel engine,reduce emission,and to further devoelop the convenience and safety of the engine.First of all,this reserch focuses on analizing the influence of charge air pressure on load surge performance,the temperature of the exhaust gas after turbocharger and the concentration of the exhaust gas pollutant.This paper also pays special attention to studying the charge air pressure control technology based on fuzzy control optimization,including the charge air pressure limiting PID control strategy,exhaust gas temperature fuzzy PID control strategy,turbocharger jet assist fuzzy control strategy,etc.By controlling the charge air blow off valve and the jet assist solenoid valve installed on the diesel engine,the technology can quickly and accurately control the diesel engine charge air pressure,exhaust temperature and instantaneous adjustment of air-fuel ratio,so as to achieve the performance optimization of the diesel engine,energy saving and emission reduction goals.At the same time,the MATLAB software as the fuzzy controller simulation platform,using Simulink tool to expand the exhaust temperature conventional PID control simulation and fuzzy PID control simulation;Using FIS tool to carry out the calculation of turbocharger jet assist duration.By comparing and analyzing the simulation results,the feasibility and effectiveness of fuzzy PID control of exhaust temperature and fuzzy algorithm of jet assist time are verified.This paper studies the new monitoring and security technology of diesel engine synchronously as well,and designs control strategies such as control transfer,starting,stop,alarm,emergency stop and so on.Secondly,this paper designs a set of diesel engine charge air pressure control and monitoring safety system based on PLC and touch screen,including the overall design of the system,each installed sensor design,power supply design,PLC and touch screen design,input and output interface distribution,box and wiring design.With Siemens TIA Portal software as the platform,the PLC software design and touch screen HMI interface design for each function of the system,the new technology and the new program of this paper is productized.Finally,the diesel engine charge air pressure control and monitoring safety system designed in the study was installed on a L28/32 H diesel engine,and a large number of real data such as charge air pressure,exhaust temperature,Nox concentration,dynamic response,black smoke visibility and so on were actually measured.Through the research and analysis of various data,it is proved that the charge air pressure control technology plays the role of optimizing the diesel engine performance,reducing the exhaust pollutants.At the same time,the monitoring and security functions such as side control and display,safety protection and alarm are tested,and the practicability,convenience and safety of the monitoring and security functions of the system are verified.The design of the Marine diesel engine charge air pressure control and monitoring safety system in this paper can be applied to many classic diesel engines,such as MAN-ES L23/30 H,L28/32 H,etc.,which has high market demand and application and promotion value.