Although direct measurements of the fuel injection pressure and the travel of the injector needle in conjunction with measurements of the valve train mechanism timing can provide complete diagnostic information about the technical conditions of the fuel injection and valve train systems, this requires the installation of sensors and other equipment directly into the systems, which is possible within research laboratories but is generally forbidden during operation of the ship. Malfunctions in the fuel injection and valve train systems can also be identified from the indicator diagrams of an engine operating cycle, expressed as P(V) and P(deg) diagrams. The basic parameters of the engine operating cycle, such as the maximum combustion pressure Pmax, compression pressure Pcompr, and indicated mean effective pressure IMEP, can also be used to indicate deviations from proper engine operation. Using a combination of a vibration sensor with an in-cylinder gas pressure sensor widens the capabilities of diagnostics for marine diesel engines under operational conditions. A vibration sensor with a magnetic base can help in determining the timings of the lifting and landing of the injector needle, fuel delivery by the fuel injection pump, opening and closing of the circulation of heated heavy fuel oil, and opening and closing of the gas distribution valves. This also offers a promising solution for diagnostics of the cylinder lubrication oil injectors. The proposed approach allows valuable information to be received during engine operation in accordance with the principle of non-destructive control, and can help in early detection of possible engine malfunctions.

The application of Digital Twins is a promising solution for enhancing the efficiency of marine power plant operation, particularly their important components – marine internal combustion engines (ICE). This work presents the concept of applying a Performance Digital Twin for monitoring the technical condition and diagnosing malfunctions of marine ICE, along with its implementation on an experimental test-bench, based on a marine diesel-generator. The main principles of implementing this concept involve data transmission technologies, from the sensors installed on the engine to a server. The Digital Twin, also operating on the server, is used to automatically process the acquired experimental data, accumulate statistics, determine the current technical state of the engine, identify possible malfunctions, and make decisions regarding changes in operating programs. The core element of the Digital Twin is a mathematical model of the marine diesel engine’s operating cycle. In its development, significant attention was devoted to refining the fuel combustion model, as the combustion processes significantly impact both the engine’s fuel efficiency and the level of toxic emissions of exhaust gases. The enhanced model differs from the base model, by considering the variable value of the average droplets’ diameter during fuel injection. This influence on fuel vapourisation, combustion, and the formation of toxic components is substantial, as shown. Using the example of calibrating the model to the test results of a diesel engine under 27 operating modes, it is demonstrated that the application of the improved combustion model allows better adjustment of the Digital Twin to experimental data, thus achieving a more accurate correspondence to a real engine.

A vibration sensor as a part of the IMES GmbH diagnostic systems provides enhanced diagnostic capabilities for marine engines. Although direct measurements of the fuel injection and valve train system parameters could give complete diagnostic information about their technical conditions, such measurements usually are forbidden at navigation. Application of the vibration sensor provides reasonable alternative to direct measurements as it enables detection of the injector’s needle rise and landing timing, as well as the timing of the start of a fuel delivery and fuel cut-off by the high-pressure fuel injection pump. The heated heavy fuel oil circulation opening and closing timing together with the intake and exhaust valves closing and, for some cases, opening timing could also be measured by vibration sensor. This article shows examples of diagnostics of the fuel injection and the valve-train system various malfunctions using vibration diagrams and a mathematical simulation of the engine operating process.

Operability and efficiency of transport diesel engines significantly depend on periodical diagnosis of its technical condition. The article considers the features of monitoring and diagnostic of transport diesel engines with the help of vibroacoustic analysis of high pressure fuel equipment and gas distribution mechanism. Functional scheme of diagnostic system and analytical method of TDC determination is described. Article gives an example of four-stroke and two-stroke diesel engines diagnosis. Also the article shows turbocharger speed determination and diagnosis with the help of vibroacoustic spectrum analysis. The main feature of the given methods is their high efficiency for diagnosis of transport diesel engines during operation.

The article discusses methods for determining top dead center, based on the analysis of pressure diagrams of a marine engine. The advantages and disadvantages of different methods are shown. Diagnostics of marine engines during operation and the selection of optimal operating conditions is based...

This paper discusses hardware-based methods for monitoring the operational parameters of marine diesel engines and online mathematical modeling techniques (digi