Zalozh V. Efficiency control improvement of diesel engines conditions by using the method of analytical synchronization of monitored data

The thesis is devoted to the actual problem of analytical synchronization of data monitoring working process in transport diesel engines operation. The solution to this problem attaches great importance in operation. The accuracy of data synchronization determines the error in determining power, control of the main engine systems operation and its diagnostics. The advantages and disadvantages of different methods are disclosed. Diagnostics of marine engines during operating and the selection of optimal operating conditions is based on the analysis of gas pressure diagrams, as well as fuel supply and gas distribution diagrams. As a result of the analysis of the pressure diagrams, the indicator engine power is calculated, which is further used in the management of engine operation modes, in the calculation of specific indicators, as well as in the calculation of energy efficiency coefficients of marine vessels according to International maritime organization recommendations. The influence of the accuracy of determining the position of the top dead center on the calculation of the mean indicated pressure and indicator power is classified. The error of the hardware sensors is so large and unstable depending on the load that it became obvious that within this error and even more accurately, the position of the top dead center can be calculated by analyzing of the gas pressure diagrams. On the other hand, the influence of the top dead center error on the accuracy of calculating the average indicator pressure is very large: 6…9 % per 1° top dead center error. Thus, in order to obtain an acceptable calculation of the average indicator pressure and indicator power, it is necessary to determine the top dead center with a maximum absolute error of not more than 0,1…0,3 degrees of crankshaft rotation. An analytical synchronization method is developed based on the top dead center coordinate determination algorithm, which uses three stages: linear, sinusoidal and model equal to zero the first derivative of the pressure under compression. The model equal to zero the first derivative of the pressure under compression is simulated from the closing of the intake valves to the start of ignition in the cylinder. Appropriate boundaries are determined by analyzing the extreme of the curves first and second derivative of the pressure under compression, which is possible after filtering the initial pressure curve. The author has applied digital filter Butterworth Low Pass filter that has a smooth characteristic across the frequency range and does not offset the phase of the original signal. This ensures the required accuracy of the final calculation of the average indicator pressure with the subsequent calculation of the indicator and effective engine power with a maximum relative error of no more than 2.5%. The developed algorithms and methods have been used in the new version of the marine diesel monitoring system software DEPAS D4.0HT, used by the shipping company TRANSSHIP (Ukraine), on shore diesel power plants and diesel locomotives.