scholarly journals The time of the first transition of the semi-Markov process in the evaluation of diesel engine operation

2011 ◽  
Vol 145 (2) ◽  
pp. 89-98
Author(s):  
Jacek RUDNICKI
Keyword(s):  
Diesel Engine ◽  
Markov Process ◽  
Markov Processes ◽  
Marine Diesel Engine ◽  
Engine Operation ◽  
Marine Diesel ◽  
Semi Markov Process ◽  
Deterioration Process ◽  
Semi Markov Processes ◽  
Engine Reliability

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.

General solidarity theorems for semi-Markov processes

1972 ◽  
Vol 9 (04) ◽  
pp. 789-802
Author(s):  
Choong K. Cheong ◽  
Jozef L. Teugels
Keyword(s):  
Markov Process ◽  
Markov Processes ◽  
Transition Probabilities ◽  
Large Set ◽  
Semi Markov Process ◽  
Regularly Varying ◽  
Specific Pair ◽  
Semi Markov Processes

Let {Zt, t ≧ 0} be an irreducible regular semi-Markov process with transition probabilities Pij (t). Let f(t) be non-negative and non-decreasing to infinity, and let λ ≧ 0. This paper identifies a large set of functions f(t) with the solidarity property that convergence of the integral ≧ eλtf(t)Pij (t) dt for a specific pair of states i and j implies convergence of the integral for all pairs of states. Similar results are derived for the Markov renewal functions Mij (t). Among others it is shown that f(t) can be taken regularly varying.

scholarly journals Possibility of Application of the Theory of Semi-Markov Processes to Determine Reliability of Diagnosing Systems / MOŻLIWOŚĆ ZASTOSOWANIA TEORII PROCESÓW SEMI-MARKOWA DO OKREŚLENIA NIEZAWODNOŚCI SYSTEMÓW DIAGNOZUJĄCYCH

2012 ◽  
Vol 24 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Jerzy Girtler
Keyword(s):  
Markov Process ◽  
Markov Processes ◽  
Continuous Time ◽  
Diagnostic Tests ◽  
The State ◽  
Actual State ◽  
Reliability Model ◽  
Discrete State ◽  
Semi Markov Process ◽  
Semi Markov Processes

Abstract The paper provides justification for the necessity to define reliability of diagnosing systems (SDG) in order to develop a diagnosis on state of any technical mechanism being a diagnosed system (SDN). It has been shown that the knowledge of SDG reliability enables defining diagnosis reliability. It has been assumed that the diagnosis reliability can be defined as a diagnosis property which specifies the degree of recognizing by a diagnosing system (SDG) the actual state of the diagnosed system (SDN) which may be any mechanism, and the conditional probability p(S*/K*) of occurrence (existence) of state S* of the mechanism (SDN) as a diagnosis measure provided that at a specified reliability of SDG, the vector K* of values of diagnostic parameters implied by the state, is observed. The probability that SDG is in the state of ability during diagnostic tests and the following diagnostic inferences leading to development of a diagnosis about the SDN state, has been accepted as a measure of SDG reliability. The theory of semi-Markov processes has been used for defining the SDG reliability, that enabled to develop a SDG reliability model in the form of a seven-state (continuous-time discrete-state) semi-Markov process of changes of SDG states.

scholarly journals Monounireducible Nonhomogeneous Continuous Time Semi-Markov Processes Applied to Rating Migration Models

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Guglielmo D'Amico ◽  
Jacques Janssen ◽  
Raimondo Manca
Keyword(s):  
Distribution Function ◽  
Markov Process ◽  
Markov Processes ◽  
Continuous Time ◽  
Topological Structure ◽  
Credit Rating ◽  
Fundamental Importance ◽  
Sufficient Condition ◽  
Semi Markov Process ◽  
Semi Markov Processes

Monounireducible nonhomogeneous semi- Markov processes are defined and investigated. The mono- unireducible topological structure is a sufficient condition that guarantees the absorption of the semi-Markov process in a state of the process. This situation is of fundamental importance in the modelling of credit rating migrations because permits the derivation of the distribution function of the time of default. An application in credit rating modelling is given in order to illustrate the results.

Markov-renewal fluid queues

2004 ◽  
Vol 41 (3) ◽  
pp. 746-757 ◽  
Author(s):  
Guy Latouche ◽  
Tetsuya Takine
Keyword(s):  
Markov Process ◽  
Exponential Distribution ◽  
Stationary Distribution ◽  
Markov Processes ◽  
Input Rate ◽  
Fluid Queue ◽  
Birth And Death Processes ◽  
Fluid Queues ◽  
Semi Markov Process ◽  
Semi Markov Processes

We consider a fluid queue controlled by a semi-Markov process and we apply the Markov-renewal approach developed earlier in the context of quasi-birth-and-death processes and of Markovian fluid queues. We analyze two subfamilies of semi-Markov processes. In the first family, we assume that the intervals during which the input rate is negative have an exponential distribution. In the second family, we take the complementary case and assume that the intervals during which the input rate is positive have an exponential distribution. We thoroughly characterize the structure of the stationary distribution in both cases.

scholarly journals A Model of Fuel Combustion Process in The Marine Reciprocating Engine Work Space Taking Into Account Load and Wear of Crankshaft-Piston Assembly and The Theory of Semi-Markov Processes

2016 ◽  
Vol 23 (3) ◽  
pp. 50-57 ◽  
Author(s):  
Jerzy Girtler
Keyword(s):  
Markov Processes ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Diesel Oil ◽  
Fuel Combustion ◽  
Engine Operation ◽  
Work Space ◽  
State Process ◽  
Marine Diesel ◽  
Semi Markov Processes

Abstract The article analyses the operation of reciprocal internal combustion engines, with marine engines used as an example. The analysis takes into account types of energy conversion in the work spaces (cylinders) of these engines, loads of their crankshaft-piston assemblies, and types of fuel combustion which can take place in these spaces during engine operation. It is highlighted that the analysed time-dependent loads of marine internal combustion engine crankshaft-piston assemblies are random processes. It is also indicated that the wear of elements of those assemblies resulting from their load should also be considered a random process. A hypothesis is formulated which explains random nature of load and the absence of the theoretically expected detonation combustion in engines supplied with such fuels as Diesel Oil, Marine Diesel Oil, and Heavy Fuel Oil. A model is proposed for fuel combustion in an arbitrary work space of a marine Diesel engine, which has the form of a stochastic four-state process, discrete in states and continuous in time. The model is based on the theory of semi-Markov processes.

An Experimental Study on Fuel Economy Improvement of a Marine Diesel Engine Using a Sequential Turbocharging System

2018 ◽  
Author(s):  
Hechun Wang ◽  
Xiannan Li ◽  
Yinyan Wang ◽  
Hailin Li
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Engine Speed ◽  
Single Stage ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Engine Operation ◽  
Marine Diesel ◽  
High Torque

Marine diesel engines usually operate on a highly boosted intake pressure. The reciprocating feature of diesel engines and the continuous flow operation characteristics of the turbocharger (TC) make the matching between the turbocharger and diesel engine very challenging. Sequential turbocharging (STC) technology is recognized as an effective approach in improving the fuel economy and exhaust emissions especially at low speed and high torque when a single stage turbocharger is not able to boost the intake air to the pressure needed. The application of STC technology also extends engine operation toward a wider range than that using a single-stage turbocharger. This research experimentally investigated the potential of a STC system in improving the performance of a TBD234V12 model marine diesel engine originally designed to operate on a single-stage turbocharger. The STC system examined consisted of a small (S) turbocharger and a large (L) turbocharger which were installed in parallel. Such a system can operate on three boosting modes noted as 1TC-S, 1TC-L and 2TC. A rule-based control algorithm was developed to smoothly switch the STC operation mode using engine speed and load as references. The potential of the STC system in improving the performance of this engine was experimentally examined over a wide range of engine speed and load. When operated at the standard propeller propulsion cycle, the application of the STC system reduced the brake specific fuel consumption (BSFC) by 3.12% averagely. The average of the exhaust temperature before turbine was decreased by 50°C. The soot and oxides of nitrogen (NOx) emissions were reduced respectively. The examination of the engine performance over an entire engine speed and torque range demonstrated the super performance of the STC system in extending the engine operation toward the high torque at low speed (900 to 1200 RPM) while further improving the fuel economy as expected. The engine maximum torque at 900 rpm was increased from 1680Nm to 2361 Nm (40.5%). The average BSFC over entire working area was improved by 7.4%. The BSFC at low load and high torque was significantly decreased. The application of the STC system also decreased the average NOx emissions by 31.5% when examined on the propeller propulsion cycle.

Quasi-stationary distributions in semi-Markov processes

1970 ◽  
Vol 7 (02) ◽  
pp. 388-399 ◽  
Author(s):  
C. K. Cheong
Keyword(s):  
Markov Process ◽  
State Space ◽  
Markov Processes ◽  
Transition Probability ◽  
Main Concern ◽  
Initial State ◽  
Stationary Distributions ◽  
Semi Markov Process ◽  
Image Position ◽  
Semi Markov Processes

Our main concern in this paper is the convergence, as t → ∞, of the quantities i, j ∈ E; where Pij (t) is the transition probability of a semi-Markov process whose state space E is irreducible but not closed (i.e., escape from E is possible), and rj is the probability of eventual escape from E conditional on the initial state being i. The theorems proved here generalize some results of Seneta and Vere-Jones ([8] and [11]) for Markov processes.

Markov-renewal fluid queues

2004 ◽  
Vol 41 (03) ◽  
pp. 746-757
Author(s):  
Guy Latouche ◽  
Tetsuya Takine
Keyword(s):  
Markov Process ◽  
Exponential Distribution ◽  
Stationary Distribution ◽  
Markov Processes ◽  
Input Rate ◽  
Fluid Queue ◽  
Birth And Death Processes ◽  
Fluid Queues ◽  
Semi Markov Process ◽  
Semi Markov Processes

We consider a fluid queue controlled by a semi-Markov process and we apply the Markov-renewal approach developed earlier in the context of quasi-birth-and-death processes and of Markovian fluid queues. We analyze two subfamilies of semi-Markov processes. In the first family, we assume that the intervals during which the input rate is negative have an exponential distribution. In the second family, we take the complementary case and assume that the intervals during which the input rate is positive have an exponential distribution. We thoroughly characterize the structure of the stationary distribution in both cases.

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