3rd TAGRA

Compression ratio is one of the most important design parameters of compression-ignition engines, directly affecting the combustion process, engine performance, fuel consumption, and emissions. In this study, the effect of compression ratio on the performance of a single-cylinder Ruston & Hornsby 1YWA diesel engine was investigated using the GT-SUITE software. First, a one-dimensional engine model was developed in the GT-SUITE environment based on the engine’s geometric and operating specifications, including cylinder bore, piston stroke, displacement volume, direct fuel injection system, and operating conditions. The model results were then validated against reliable data available in the scientific literature in terms of the variation in in-cylinder pressure. Subsequently, the effects of three compression ratios, 16, 17, and 18, over an engine speed range of 1000–2000 rpm were evaluated with respect to performance parameters, including in-cylinder pressure and temperature, brake mean effective pressure (BMEP), brake-specific fuel consumption (BSFC), and brake-specific carbon monoxide (CO) emissions. The simulation results showed that increasing the compression ratio increased the peak pressure and temperature within the combustion chamber, improved the combustion process, and increased the brake mean effective pressure. Furthermore, an increase in compression ratio resulted in a reduction in both brake-specific fuel consumption and carbon monoxide emissions at all engine speeds, indicating improved thermal efficiency and more complete combustion of the fuel. Investigation of the effect of engine speed showed that increasing engine speed increased the peak in-cylinder pressure and temperature, whereas BMEP exhibited a decreasing trend and BSFC showed an increasing trend. Overall, a compression ratio of 18:1 provided the most favorable performance in terms of improving efficiency and reducing fuel consumption and CO emissions. The results of this study demonstrate that optimization of the compression ratio can be an effective approach for improving the performance of single-cylinder diesel engines and reducing energy consumption.