Calculation and Optimizing of Brake Thermal Efficiency of Diesel Engines Based on Theoretical Diesel Cycle Parameters

Abstract

In this study, a theoretical study has been evaluated in order to calculate and optimize diesel engine brake thermal efficiency values. In the study three main parameters which are compression ratio, ratio of specific heat and cut-off ratio, based on ideal diesel cycle were evaluated. Compression ratio, ratio of specific heats and cut-off ratios were chosen between the interval of; 12:1-24:1, 1,2-1,4 and 1,5-3,0, respectively. Theoretical study showed that compression ratio significantly affects the engine characteristics that calculated in this study. Experiments revealed that the higher compression ratio results with higher brake thermal efficiency (BTHE) and thus lower specific fuel consumption (SFC). The calculation study showed that increasing cut-off ratio caused to decrease of brake thermal efficiency. Also, study revealed that increment of ratio of specific heats improved brake thermal efficiency.