Research On Thermal Fault Simulation And Diagnosis For Marine Medium-speed Diesel Engine

The most malfunctions in the equipments of the ship is aroused by marine diesel enginewhich is the main power of the ship, the security and reliability of the whole power plant isdetermined by the working state of diesel engine. The research on fault diagnosis of dieselengine is of great importance which could enhance safety, save the maintenance cost, reducepollution and energy consumption. The thermal fault is one of the most common, and multiplefault, it’s final and external performance is that the thermal process parameters are abnormalregardless of the cause of the fault. With the development of modern diesel engine, the on-linemonitoring technology of thermal parameters is more and more mature, which provides a goodfoundation for the thermal fault diagnosis. Taking the4190type medium-speed marine dieselengine manufactured by JiChai Power Equipment Company as the research object, a faultsimulation model of the diesel engine is built, the research on diesel engine thermal faultsimulation and diagnosis by using the simulation model and set pair analysis provides a certainbasis and methods for the evaluation of diesel engine working state and thermal fault diagnosis.Firstly, the development status of diesel engine working process simulation, faultsimulation and diagnosis are discussed in this paper, the program for marine diesel engine faultsimulation and diagnosis technique is made sure. A quasi dimension fault simulation model oftransformed4190diesel engine is established by using AVL_BOOST Software. Theexperimental data is used to calibrate the BOOST model and to verify the correctness of themodel.Secondly, a fault simulation program is set up, according to the theory of fault simulation.Eight faults which includes injection timing fault, one cylinder misfiring, fuel injector nozzleholes wearing, intercooler efficiency decreasing, turbocharger efficiency decreasing, exhaustvalve closing timing fault, crankcase blow-by and single-cylinder fuel supply uneven aresimulated and calculated under different severity, the change rules of thirteen thermalparameters under different faults are made sure, a fault database of the thermal parametersunder different faults is established, which provides a numerical basis for quantitative analysisof diesel engine fault diagnosis.Finally, the basic theory of set pair analysis is discussed, there is feasibility to apply SPA tofault diagnosis of diesel engine. A model of diesel engine fault diagnosis is built up based onSPA, which can be used to analyze how close the working states with standard states, and it is proved to be correct. The fault diagnosis model is programmed by Visual Basic6.0, which canbe used to analyze and to judge the diesel engine working status simply, rapidly and accurately.