Research On Reliability Of Diesel Engine Based On Fault Tree Method

As the main power input of various mechanical equipment,diesel engines play a great role in daily production and work.With the continuous progress of diesel engine technology,the standards for measuring its quality have not only been included in the design and manufacturing parts,and diesel engine reliability research has also become an important direction.Research on the reliability of diesel engine components and finding weakness in the system will not only help improve its reliability at work,but also provide great convenient for personnel use or maintenance.The fault tree analysis method is combined with fuzzy mathematics theory to overcome the uncertainty of complex problems.The fuzzy fault tree analysis method is used to analysis the reliability of the diesel engine valve failure,which solves the difficulty of obtaining accurate probability of some bottom events.The qualitative analysis is carried out to get all the minimum cut sets of the valve failure fault tree by upward method.The fuzzy probability of the top event is calculated.For the triangular fuzzy number,the median method is used to obtain the fuzzy importance of each bottom event,find the key bottom events that affect valve failure by comparison.In view of the inadequacy of the two-state fault tree analysis method in dealing with multiple fault problems,a multi-state T-S fuzzy fault tree analysis method is proposed to analyze the reliability of abnormal wear of a diesel engine cylinder liner,providing two different reliability calculation method based on fault probability or fault state of the bottom events,also the T-S fuzzy probability importance and T-S fuzzy critical importance of each bottom event while cylinder liner wear at different fault levels are calculated respectively.Through comparison,the key bottom events of cylinder liner wear under different fault levels are found..The valve failure fault tree is used as a mathematical model,and a Monte Carlo simulation program is designed by Matlab programming language for simulation test verification.Various calculation methods of the simulation index such as mean time to failure and the importance of the bottom event are provided.The dynamic curves of parameters such as reliability and failure probability change as working time are obtained,by comparison among simulation results and theoretical results,the accuracy of the method is verified.The Matlab GUI interface is used to design the fault tree reliability analysis software.With the powerful computing power of the computer,the functional requirements of software development are realized.Users only need to complete the data conversion and input according to the requirements,and they can quickly realize the qualitative analysis and reliability simulation functions of fault tree,which provides great convenience for engineering personnel.