The semi-Markov model of energy state changes of the main marine internal combustion engine and method for evaluating its operation during ship voyage

Abstract

The article presents a method for evaluating the operation of internal combustion engines used as the main engines in the propulsion systems of sea-going ships in various operating conditions. This method enables calculating the engine operation value based on the theory of semi-Markov processes and mathematical statistics. What is noteworthy, the operation of the examined internal combustion engines is compared to a physical quantity which is expressed in the form of a number with the measure unit called joule-second. A model having the form of a semi-Markov process is proposed to describe the energy state changes taking place in the main engines during their operation. Also proposed is the use of the point and interval estimation at a given confidence level β for determining the value of the energy converted in the engine during its operation for the known and unknown standard energy deviation treated as the random variable. The semi-Markov model of changes of the energy converted in the engine during its operation is presented in a general form. The above model was used for determining the ship’s main engine operation, which is in the examined case a function of the energy converted in particular energy states, the expected value of the time of duration of these states and the probability of their existence. These probabilities compose the limiting distribution of the semi-Markov process, the values of which are the specified main engine energy states.