Faculty Publications
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Publications by NITK Faculty
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Item Experimental Investigation of Variations in Spark Timing using a Spark-Ignition Engine with Hydrogen-Blended Gasoline(Wiley-VCH Verlag info@wiley-vch.de, 2015) Shivaprasad, K.V.; Chitragar, P.R.; Kumar, G.N.This study describes an experiment conducted using an electronically controllable single-cylinder high-speed gasoline engine to analyze the performance and emissions characteristics of various hydrogen-gasoline blends. The experiments have been conducted for various engine speeds and spark timings at the wide open throttle position. The experimental results revealed that the engine brake thermal efficiency and brake mean effective pressure first increase and then decrease with the increase engine speed at all spark timings. The minimum amount of brake specific energy consumption was observed for 20% hydrogen addition in the total fuel blend at 3000rpm engine speed and 14°crank angle (CA) before top dead center (BTDC) spark timing. Hydrocarbon and carbon monoxide emissions were reduced with the retardation of spark timings. Nitrogen oxide emissions were continuously increased with the addition of hydrogen in the fuel blend as well as spark timing advance. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Performance and emission analysis of a single cylinder CI engine using Simarouba glauca biodiesel(Springer Heidelberg, 2017) Bedar, P.; Chitragar, P.R.; Shivaprasad, K.V.; Kumar, G.N.It is well known fact that diesel engines are commonly used for transportation and power generation due to their high efficiency, low fuel consumption and durability. On contrary these engines churn out harmful and hazardous emissions like particulate matter (PM) and nitrogen oxides (NOx). Recently Bio-origin renewable fuels have taken center stage of discussion because of their ability to replace depleting fossil fuels and capacity to reduce hazardous engine exhausts emissions when used in diesel engines. In the present experimental study Simarouba glauca biodiesel is used in a naturally aspirated four stroke single cylinder air cooled direct injection kirloskar DA10 engine. The main objective is to investigate the effect of biodiesel and exhaust gas recirculation (EGR) on the performance and emission characteristics of a CI engine at 180 bar fuel injection pressure (FIP) with standard injection timing. B20, B40 biodiesel blends with 10, 15 and 20% EGR ratios were used for the study to investigate brake thermal efficiency (BTE), carbon monoxide (CO), unburned hydrocarbons (UBHC), NOx, and smoke opacity. Reduction in CO, HC and smoke opacity is noticed with simarouba biodiesel fuel while increasing NOx compared to diesel. Application of EGR along with biodiesel resulted in simultaneous reduction of nitrogen oxides and smoke without affecting engine performance. It was found from experiment that B20 blend at 15% EGR shown superior performance characteristics compared to other conditions. © Springer India 2017.Item Computational fluid dynamic analysis of the effect of inlet valve closing timing on common rail diesel engines fueled with butanol–diesel blends(Frontiers Media SA, 2024) Lamani, V.T.; Shivaprasad, K.V.; Roy, D.; Yadav, A.K.; Kumar, G.N.The inlet valve closing (IVC) timing plays a crucial role in engine combustion, which impacts engine performance and emissions. This study attempts to measure the potential to use n-butanol (Bu) and its blends with the neat diesel in a common rail direct injection (CRDI) engine. The computational fluid dynamics (CFD) simulation is carried out to estimate the performance, combustion, and exhaust emission characteristics of n-butanol–diesel blends (0%–30% by volume) for variable valve timings. An experimental study is carried out using standard valve timing and blends to validate the CFD model (ESE AVL FIRE). After validation, the CFD model is employed to study the effect of variable valve timings for different n-butanol–diesel blends. Extended coherent flame model-3 zone (ECFM-3Z) is implemented to conduct combustion analysis, and the kappa–zeta–f (k–ζ–f) model is employed for turbulence modeling. The inlet valve closing (IVC) time is varied (advanced and retarded) from standard conditions, and optimized valve timing is obtained. Advancing IVC time leads to lower cylinder pressure during compression due to reduced trapped air mass. The brake thermal efficiency (BTE) is increased by 4.5%, 6%, and 8% for Bu10, Bu20, and Bu30, respectively, compared to Bu0. Based on BTE, optimum injection timings are obtained at 12° before the top dead center (BTDC) for Bu0 and 15° BTDC for Bu10, Bu20, and Bu30. Nitrogen oxide (NOx) emissions increase due to complete combustion. Due to IVC timing, further carbon monoxide and soot formation decreased with blends and had an insignificant effect. © © 2024 Lamani, Shivaprasad, Roy, Yadav and Kumar.