Diagnostic Information Analysis of Quickly Changing Temperature of Exhaust Gas from Marine Diesel Engine Part I Single Factor Analysis

Abstract

In this paper, attention was paid to the problem of low controllability of marine medium- and high-speed engines during operation, which significantly limits the parametric diagnosis. The measurement of quickly changing temperature of engine exhaust gas was proposed, the courses of which can be a source of diagnostic information. The F statistic of the Fisher-Snedecor distribution was chosen as a statistical tool. Laboratory tests were carried out on the bench of a Farymann Diesel engine. The tests consisted of introducing the real changes in the constructional structure of the considered functional systems of the engine. Three changed parameters for the structure were reviewed: the active cross-sectional area of the inlet air channel, injector opening pressure and compression ratio. Based on the recorded plots of the quick-changing temperatures of the exhaust gases, three diagnostic measures were defined and subjected to statistical tests. The following data were averaged over one cycle for a 4-stroke piston engine operation, (1) the peak-to-peak value of the exhaust gas temperature, (2) the specific enthalpy of the exhaust gas, and (3) the rate of increase and decrease in the values for the quick-changing exhaust gas temperature. In this paper will present results of the first stage of the elimination study: the one-factor statistical analysis (randomised complete plan). The next part will present the results of the second stage of studies: two-factor analysis (block randomised plan), where the significance of the effect of changing the values of the structure parameters on the diagnostic measures was analysed in the background of a variable engine load.

Development of a New Expert System for Diagnosing Marine Diesel Engines Based on Real-Time Diagnostic Parameters

“…One of the primary weaknesses of present marine diesel engine fault diagnostic systems is the inability to perform real-time fault diagnosis of diesel engines [16]. Each diagnostic parameter gives a certain diagnostic signal (depending on its sensitivity) to change and sometimes to the rate of this change.…”

Quantumness in Diagnostics of Marine Internal Combustion Engines and Other Ship Power Plant Machines

“…In the diagnostics of not only marine internal combustion engines but also those used in cars, airplanes, etc., as well as other machines of all types, it is advisable to stop using the deterministic approach for the identification of the technical state of these machines and focus on the probabilistic aspects of their diagnostics [3], [6], [11], [17], [21], [24], [29], [30], [38]- [40]. The deterministic approach to the diagnostics of marine engines and machines, as well as those used in other branches of technology, results from the traditional perception of changes in their technical state, according to which it is believed that, in general, randomness and unpredictability can be omitted in technical diagnostics intended to assess the technical state of these types of devices.…”

Concept of Vibroacoustic Diagnostics of the Fuel Injection and Electronic Cylinder Lubrication Systems of Marine Diesel Engines

“…An analysis of indicator diagrams such as P(V) and P(deg), based on an examination of their shape and consideration of the main parameters (such as maximum combustion pressure Pmax, pressure at the end of compression Pcomp, indicated mean effective pressure IMEP, ignition point, etc. ), could enable the detection of a number of possible malfunctions, as shown by Varbanets et al [4][5][6][7][8][9]. These malfunctions include incorrect fuel injection timing, ore fuel distribution, wrong gas distribution valves timing, valve leakage, etc.…”