Determination of mean pressure of mechanical losses and mechanical efficiency of diesel engines by applying indicator diagram method

In the presented study; it was aimed to investigate experimentally mechanical losses in diesel engines and to obtain empirical correlations suitable to use in diesel engines. For this purpose, firstly, fundamentals of mechanical losses have been given and methods aimed to determine mechanical losses have been introduced. Then by applying one of these methods, which is called as "Indicator Diagram Method", mechanical losses in turbocharged and natural aspirated diesel engines were experimentally investigated. For applying the indicator diagram method, experiments were performed at 1/1, 3/4, 1/2 gas positions (fuel deliver rates) and no load case at the various engine speeds. Moreover, experiments were performed by using two different lubrication oil at the 1/1 gas position at the various engine speeds for turbocharged engine. The variations of mean pressure of mechanical losses, mechanical efficiency and mean pressure of gas exchange losses with respect to mean piston speed and air flow rate at various gas positions (fuel deliver rates) have been determined. All of the experimental results have also been presented as various curves and evaluated.By applying curve fitting to variations of mean pressure of mechanical losses and mean pressure of gas exchange losses values obtained by using Indicator Diagram Method; various empirical correlations consisting of 3rd degree polynomials were developed to determine mean pressure of mechanical losses and mean pressure of gas exchange losses at various gas positions in diesel engines.For purpose of applying error analysis, every measurement has been repeated 5 times at each experimental condition and Student?s-t distribution at %5 level of significance has been applied.