en موتور احتراق داخلی Internal Combustion Engines (ICE, ...) پژوهشي Research <p style="margin: 8px 0px; text-align: justify; line-height: normal; text-justify: kashida; text-kashida: 0%;"><span font-size:="" new="" style="margin: 0px; font-family: " times=""><font color="#000000">Changing various parts of different types of engines in the maintenance phase was always a remarkable question. Purpose of the present study is identifying the performance and emissions of a diesel-fueled engine (OM457) before and after replacing connecting rod and crankshaft with another engine (OM444) in the same engine family.</font></span></p> <p style="margin: 8px 0px; text-align: justify; line-height: normal; text-justify: kashida; text-kashida: 0%;"><span font-size:="" new="" style="margin: 0px; font-family: " times=""><font color="#000000">At the first step, a solid model was made then some CFD analyses were done and, results were compared with previous studies for validation after that in the CFD modeling the impact of these parts replacement were observed, and the performance and emissions of this engine were compared with data before replacements.</font></span></p> <p style="margin: 8px 0px; text-align: justify; line-height: normal; text-justify: kashida; text-kashida: 0%;"><span font-size:="" new="" style="margin: 0px; line-height: 115%; font-family: " times=""><font color="#000000">As the result of these replacements, compression ratio and performance were decreased. HC and CO were increased due to lower air-fuel ratio, and NO_X was decreased because of the lower temperature of in cylinder. Lowering the CR of a diesel engine will reduce the NOx emission numerously but the increase in other emissions will be slight. So for the environment issues lowering the CR will be a practical and low cost method.</font></span></p> Diesel fuel engine, OM457, Compression ratio, Connecting rod, Crankshaft, Performance, Emissions 3132 3139 http://ase.iust.ac.ir/browse.php?a_code=A-10-372-2&slc_lang=en&sid=1 Saeed Chamehsara saeed.chamehsara@gmail.com 180031947532846002478 180031947532846002478 No Young Researchers and Elite Club, Science and research branch, Islamic Azad University, Tehran, Iran Mohammadreza Karami mrk.mei77@gmail.com 180031947532846002479 180031947532846002479 Yes MSc of Automotive engineer, School of Automotive Engineering, Iran University of Science and Technology, Tehran, Iran