TDC Determination in IC Engines Based on the Thermodynamic Analysis of the Temperature-Entropy Diagram

Abstract

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Practical research of the angle of thermodynamic losses when indicating pressure in the cylinder diesel engine

“…After this, the original method described in reference is applied [6], with excellent results in agreement with the experimental results by Hohenberg, also there have been no shortcomings in the Hohenberg's theoretical approaches.…”

“…Explicit thermodynamic analysis of the pressure flow is quite an efficient procedure which is sensitive to errors in assessing initial conditions, while for the tracking form T-s diagram could be said that it is a lot less complex and efficient method of evaluating the ATL. In that sense, it is a very interesting method theoretically described in [6]. The efficacy of this method on a line four-cylinder engine with spark ignition of the mixture is shown in reference [7].…”

“…Later, the more modern methods were examined, which is theoretically provided in reference [6], and is based on an explicit thermodynamic analysis of pressure flow and monitoring of the T-s diagram forms with the process without combustion. This method is declared a method with a number of advantages: simply, it allows small deviations in the accuracy of determining the initial conditions of gas at the start of the compression process.…”

“…The theoretical basis of the method described in [6] is based on the analysis of equations for entropy change in compression and expansion in the immediate vicinity of the maximum T-s diagrams, and the conclusion that there must be a symmetry of Ts diagram of the process without combustion, in the immediate vicinity of the given maximum, if compression degree (ε) and ATL (∆α) are correctly determined.…”

“…Since it required high accuracy in determining the actual pressure flow in the function of the crankshaft rotation angle, and with special sensors for monitoring the status of one of the pistons not being used, the approach was using a subsequent search for the real position of TDC on measured pressure diagrams. Focusing on only one method was not reliable enough, thus a comparison with the results of an old method which contains experimentally obtained data was carried out [2], as well as a modern method [6], which promised good results. This paper is dedicated to the most important observations which have arisen from the mentioned, detailed research and its comparison with the obtained results.…”