A new analytical method to optimise the preventive maintenance interval by using a semi-Markov process and z-transform with an application to marine diesel engines

2021 ◽  
Vol 207 ◽  
pp. 107394
Author(s):  
Antonio Sánchez-Herguedas ◽  
Angel Mena-Nieto ◽  
Francisco Rodrigo-Muñoz
2017 ◽  
Vol 24 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Zbigniew Łosiewicz

Abstract The article discusses the results of actions performed by marine engine manufacturers towards the reduction of emission of harmful substances in the exhaust gas from these engines. The discussion is limited to main engines produced by MAN B&W. A model is proposed to describe the process of emission of harmful substances from Diesel engines based on the semi-Markov process, discrete in states and continuous in the operating time. The states of this process are: engine ability state (s1) and engine inability state (s2). A method to calculate probabilities P1 and P2 of the appearance of states s1 and s2 is proposed. State s1 is interpreted as corresponding to the inequality ek<ek(dop), while state s2 is characterised by the inequality ek>ek(dop), where ek represents the mass of harmful substances emitted by the engine during its operation and ek(dop) is the maximum mass of emission of these substances permitted by relevant regulations.


1986 ◽  
Vol 10 (4) ◽  
pp. 201-211 ◽  
Author(s):  
M.R. Haddara ◽  
M.A. Younis

Recent instances of marine crankshaft failure were attributed to secondary resonance which is a consequence of variable inertia. More insight into the secondary resonance producing mechanism may be gained by considering the effect of connecting rod obliquity. In this work an analytical method for the study of the effect of variable inertia, taking into account the obliquity of the connecting rod, is developed. New resonant frequencies are found. Expressions defining the boundaries between resonant and non-resonant solutions are derived. Moreover, numerical solutions are obtained using a fourth order Runge-Kutta algorithm. Results obtained from both approaches are in agreement.


2022 ◽  
pp. 137-161
Author(s):  
Antonio Sánchez-Herguedas ◽  
Adolfo Crespo-Márquez ◽  
Francisco Rodrigo-Muñoz

This chapter uses a semi-Markov process and the z transform to find the optimal preventive maintenance interval when dealing with maintenance decision making for a finite time planning horizon. The result is a method that can be easily implemented to assets for which a Weibull reliability analysis exists. The suggested preventive interval formulation is simple and practical. The requirements to apply this simple formula are related to the existence of asset´s reliability data as well as cost/rewards that the assets have when remaining or transitioning to a given state. The application of this method can be very straightforward, and the tool can become a good decision support tool allowing “what if” analysis for different time horizon and maintenance policies.


Author(s):  
M. A. Hossain Mollah

Abstract Maintenance is becoming increasingly an important element in the upkeep of the modern complex equipment. There are a number of approaches to the maintenance of the equipment such as the break down maintenance and preventive maintenance. Marine diesel engines require proper maintenance to ensure their efficient, safe and trouble-free operation. The preventive maintenance task that is most useful for reducing the overall maintenance, is also known as on-condition maintenance, condition-directed maintenance, or predictive maintenance. This is done by measuring some parameter over time where it has been established that parameter correlates well with the incipient failure conditions. This paper contains the studies of the evaluation of combustion chamber leakage of four stroke marine diesel engines by using a diagnostic device. It describes the methodology to develop the performance limits of the combustion chamber leakage of marine diesel engine and the method of evaluating the condition of diesel engines. The results of model tests of the diagnostic device, Pneumatic Indicator, are also reported. The proposed methodology allows performing the evaluation of the technical condition of a cylinder piston group of marine engines both qualitative and quantitative. Thus the maintenance and repairing works may be performed according to the real condition of the engine, which is extremely useful in decreasing the overall maintenance cost.


2011 ◽  
Vol 145 (2) ◽  
pp. 89-98
Author(s):  
Jacek RUDNICKI

The paper presents the extension of the method discussed in the literature of quantitative evaluation of operation on the example of a marine engine. According to this interpretation, the engine operation can be shown as a physical quantity. In this aspect, based on the main marine diesel engine an evaluation of the usefulness of this index for the description of the engine reliability related properties has been performed. Apart from the generally used reliability indexes, it seems purposeful to consider the engine operation (as well as its functional subsystems) in the evaluative way, so that it could be described by both energy and time. In this aspect, in the analysis the semi-Markov processes theory was used that allowed a description of the concept of the model of the engine deterioration process as a random one. The problem of the time of the first transition of the semi-Markov process to a subset of specified classes of states representing particular technical and reliability-related states of engine was described in detail.


1993 ◽  
Vol 30 (3) ◽  
pp. 548-560 ◽  
Author(s):  
Yasushi Masuda

The main objective of this paper is to investigate the conditional behavior of the multivariate reward process given the number of certain signals where the underlying system is described by a semi-Markov process and the signal is defined by a counting process. To this end, we study the joint behavior of the multivariate reward process and the multivariate counting process in detail. We derive transform results as well as the corresponding real domain expressions, thus providing clear probabilistic interpretation.


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