Evaluation of current developments and trends in the diagnosis of marine diesel engines based on the indicator diagrams analysis

The paper analyses the current offer of combustion pressure sensors for use on marine engines under operating conditions, methods of data acquisition, methods of determining TDC position and methods of obtaining diagnostic information from the indicator diagrams. Terms of continuous work on marine engines themselves only: new ABB cylinder pressure sensor, the piezoelectric sensors from KISTLER and AVL companies, but with limitations, the main ones being stability at high temperature. Another important issue for the accuracy of mean indicated pressure and heat released characteristics determination is referred to TDC position on the indicator diagrams. TDC is appropriate thermodynamic point, it is hardly determinable in the presence of interference and lack of sufficient information – but is used, for example in ABB solution. One of the sources of diagnostic information is to analyse trends in some parameters, which, unfortunately, is very difficult in environments with varying engine loads. Further progress in the diagnostic use of indicator diagrams should be associated with the use of the heat released characteristics and the net internal efficiency, which as shown by the results of preliminary tests can be used to assess the accuracy of the injection and combustion of fuel, including gas fuel. Supplementing these methods may be the use of vibration and noise to detect certain malfunctions.