A Non-invasive Method of Marine Engines Fuel System Diagnostics

Small naval vessels are equipped with high- and medium-speed engines with low diagnostic compliance. Faults in fuel installations are the most common cause of failure or inability to perform operational scenarios adequately. Identification of injector damage is severe as small engines are not equipped with indicators and thermocouples to measure the overall exhaust gas temperature in the exhaust manifold. The paper presents a vibration method for assessing the technical condition of a fuel installation. The proposed method is non-invasive and allows the indication of a damaged injector within a relatively short time. The paper presents simulation results verified with stand-bed tests. The research aimed to show the sensitivity and uniqueness of vibration symptoms to changes in the technical condition of fuel injection pumps. The conducted experiment confirmed the possibility of using vibration tests in the professional diagnostics of the fuel installation. These results are essential for the use of marine engines that do not have indicator valves

A Non-invasive Method of Marine Engines Fuel System Diagnostics

Small naval vessels are equipped with high- and medium-speed engines with low diagnostic compliance. Faults in fuel installations are the most common cause of failure or inability to perform operational scenarios adequately. Identification of injector damage is severe as small engines are not equipped with indicators and thermocouples to measure the overall exhaust gas temperature in the exhaust manifold. The paper presents a vibration method for assessing the technical condition of a fuel installation. The proposed method is non-invasive and allows the indication of a damaged injector within a relatively short time. The paper presents simulation results verified with stand-bed tests. The research aimed to show the sensitivity and uniqueness of vibration symptoms to changes in the technical condition of fuel injection pumps. The conducted experiment confirmed the possibility of using vibration tests in the professional diagnostics of the fuel installation. These results are essential for the use of marine engines that do not have indicator valves

Vibration Diagnostics of Marine Diesel Engines Malfunctions Connected with Injection Pumps Supported by Modelling

The article presents main causes of malfunctions in marine diesel engines fuel injection systems. The measurement section focuses on damage to injection pumps. Measurements were carried out for three technical conditions of a given cylinder injection pump. At the same time, a simplified vibration model of the engine was presented allowing to indicate sensitive components in the frequency domain enabling identification of damages to injection pumps working with individual cylinders. Finally, the results obtained by modelling were compared with the results recorded during laboratory measurements

Preliminary Calculations for Minehunter\u27s Genset Foundations

The requirements for the foundations of naval vessel engines are based on classification rules devised by classification societies or/and military standardization rules. A class guideline was published, defining the requirements, acceptance criteria and machinery seating methods. There is also a schedule of basic calculation procedures for cast resin or rubber chocks which facilitates the process of machinery foundation design, preloading force calculation, the establishment of boundary conditions etc. In case of naval vessels, typical procedures do not meet tactical requirements due to potential explosion loads. Since minehunters are mainly deployed at sea, handling active, naval mines, the shock resistance calculation for the entire machinery, including the Genset, is required. The paper presents preliminary MatLab calculation methods which can be used to analyse the type, number and location of rubber or elastomer chocks. The procedure consists of input data such as UNDEX pressure and technical data of the Genset used in the Polish Navy. Calculation results include the analysis of the dynamic interaction between the Genset and the foundation, as well as the damping effect generated by the UNDEX (UNDerwater EXplosion) shock pulse

Diagnostic Model of Fuel Installation of Marine Diesel Engine

The paper presents the results of simulation of marine diesel engine fuel injector malfunction and its effects on engine vibration. The work includes the analysis of the engine internal forces and their mathematical models. Simplifications are proposed to allow analyzing the system in one degree of freedom. The results of vibration simulations for the model with efficient fuel system and improperly adjusted injector are also presented. The comparison of simulation results with vibration measurements on the engine was also performed, the diagnostic model was identified and simulation errors were calculated. The complexity of other internal and external interactions is the subject of other studies by the authors. The paper analyzes only the effects of energy dissipation - vibration as a symptom of changes in the technical condition

Correlation analysis of vibrationtime history of shaft lines for drive units of ships used for naval mines disarmament

This paper presents comparative assessment of operation quality of drive shaft lines for the same type of seagoing vessels used on the same basin. The assessment has been made on the basis of vibration analysis. The considered objects differ from each other in terms of operation range and time. 3 ships with two shafts of lines each, have been studied. Measurements were taken in 6 measuring points: for 4 engine rotational speeds: 850, 1100, 1300 and 1500. A macro has been developed to be used for division of files into axes and time histories, each including 1024 separate measurements for each point, for every direction, each rotational speed and usable and unusable shaft lines. A correlation characteristic of time histories – normalized value of correlation function for signals suitable and unsuitable in reference to a randomly selected suitable signal, has been calculated for each combination. A characteristic of concentrated type has been accepted for standard deviation lower than 15 % of the average. A module and the sum of standard deviations have been calculated from the difference of mean values of usable and unusable for use objects, for each combination of particular characteristics. It has been assumed that the characteristic is reliable if the module of mean values difference is higher than the sum of standard deviations. Since the concentration of value for normalized correlation function of signals for usable and unusable for use units is relatively high it has been assumed that this characteristic can be worked out so as to provide reliable data to be used for assessment of their operation quality in the analyzed period of time

Detection of Changes in the Opening Pressure of Marine Engine Injectors Using Vibration Methods

Injectors of marine engines are, apart from injection pumps, a key element of the fuel injection system. Their proper operation affects the quality and time of producing the fuel-air mixture in engine cylinders. The technical condition of the injectors also has an impact on engine performance and the emission of harmful compounds into the atmosphere. One of the basic injector damages occurring during their normal operation is the change of the injector opening pressure. The article presents mathematical relations indicating the occurrence of vibration diagnostic parameters that could potentially determine changes in the opening pressure of individual injectors. A two-stage passive-active experiment was carried out during which an injector working with different spring preload force was tested. The presented results of experimental tests confirm the possibility of determining whether the injector opening pressure is within the permissible range. The presented method does not require interference in the engine operation. measurements can be made during regular operation

Detection of Changes in the Opening Pressure of Marine Engine Injectors Using Vibration Methods

Injectors of marine engines are, apart from injection pumps, a key element of the fuel injection system. Their proper operation affects the quality and time of producing the fuel-air mixture in engine cylinders. The technical condition of the injectors also has an impact on engine performance and the emission of harmful compounds into the atmosphere. One of the basic injector damages occurring during their normal operation is the change of the injector opening pressure. The article presents mathematical relations indicating the occurrence of vibration diagnostic parameters that could potentially determine changes in the opening pressure of individual injectors. A two-stage passive-active experiment was carried out during which an injector working with different spring preload force was tested. The presented results of experimental tests confirm the possibility of determining whether the injector opening pressure is within the permissible range. The presented method does not require interference in the engine operation. measurements can be made during regular operation

Shock Absorbers Damping Characteristics by Lightweight Drop Hammer Test for Naval Machines

The technical requirements for naval ships machine foundations are far more strict in comparison to merchant’s vessels. These requirements are confirmed in the military standardization of many countries. Underwater Explosion (UNDEX phenomena) detonation pulses, force naval engineers to design and implement different shock absorbers made from a wide variety of materials. This study presents the tests results of typical shock absorber designs made of various types of rubber and elastomers. The initial objective of the study was to determine the energy absorption of shock impacts, the choice of materials capable of operating within the temperature range of 0 °C to 70 °C, resistance to contact with oils and marine fuel, performance at frequencies ranging from 5 to 30,000 Hz, and absorption no less than 40% of harmonic vibration energy. Initial studies conducted on tensile testing machine were used to determine the static and dynamic stiffness of a shock absorbers. Considerations of stiffness coefficient for the linear and nonlinear range is typical for shock pulses. Further tests were carried out on a lightweight drop hammer to determine the characteristics of the damping coefficient for high-speed wave interactions—Shock Response Spectrum (SRS). The final aim of the study was to assess the repeatability of the shock absorbers response to multiple impact loads. Mechanical properties describing possibilities of tested dampers materials to absorb energy of UNDEX were also presented