Person: YILMAZ, İLKER TURGUT
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YILMAZ
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İLKER TURGUT
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Publication Metadata only Assessment of combustion and exhaust emissions in a common-rail diesel engine fueled with methane and hydrogen/methane mixtures under different compression ratio(PERGAMON-ELSEVIER SCIENCE LTD, 2020) YILMAZ, İLKER TURGUT; Sanli, Ali; Yilmaz, Ilker Turgut; Gumus, MetinThis study investigates the potential usage of the methane and hydrogen enriched methane in a turbocharged common-rail direct injection diesel engine. Methane and hydrogen/methane mixtures are sent through the air intake manifold of the engine. The engine is operated at four different loads and three different compression ratios. Results are compared amongst single diesel and dual-fuel operations at different compression ratios and load conditions. Compared to diesel, dual-fuel operations mostly generate higher and advanced peak in-cylinder gas pressure, more combustion noise, late pilot injection and start of combustion, advanced combustion center, substantial variations at ignition delay and combustion duration, a significant increase in cyclic variations at low and medium loads, and earlier heat release. Hydrogen enrichment decreases evidently specific fuel consumption. Concerning emissions, compared to diesel operation, dual-fuel operations produce higher total hydrocarbon (THC) and nitrogen oxides (NOx) but lower carbon dioxide (CO2). Hydrogen substitutions decrease THC and CO2 emissions of methane dual-fuel operations approximately between 9-29% and 1-32%, respectively. Smoke emission of dual-fuel operations is less than that of diesel at low and medium loads, whereas it sharply increases at high load. Knocking occurs at high compression ratio and load conditions with dual-fuel operations and dramatically increases with increasing hydrogen ratio. Decreasing the compression ratio notably reduces the combustion noise as well as some emissions, such as NOx, CO2 and smoke, for entire load ranges of dual-fuel and diesel operations. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Publication Metadata only The effect of hydrogen on the thermal efficiency and combustion process of the low compression ratio CI engine(PERGAMON-ELSEVIER SCIENCE LTD, 2021) YILMAZ, İLKER TURGUT; Yilmaz, Ilker TurgutIn this study, it was purposed to investigate the hydrogen enrichment effect on combustion characteristics of a low compression ratio turbocharged Common-Rail CI engine. The compression ratio was lowered from 18.25 to 16.9. Tests were conducted at 40 Nm, 60 Nm, 80 Nm, 100 Nm and 120 Nm loads at a constant 1750 rpm. Compared to the test with the original compression ratio, the low compression ratio tests yielded lower maximum cylinder pressures, maximum rate of heat releases, maximum rate of pressure rises, ringing intensity. Combustion durations increased but ignition delays fluctuated with hydrogen enrichment. The cylinder pressures, the first heat release and the first pressure rise rates increased with the higher hydrogen flow rates. Besides, the second peaks of pressure rise rates and heat release rates decreased. The hydrogen enrichment firstly increased and then decreased the brake thermal efficiency of the low compression ratio engine. Ringing intensity increased with increasing engine load and hydrogen amount.Publication Metadata only Investigation of combustion and emission characteristics in a TBC diesel engine fuelled with CH4-CO2-H-2 mixtures(PERGAMON-ELSEVIER SCIENCE LTD, 2021) YILMAZ, İLKER TURGUT; Sanli, Ali; Yilmaz, Ilker Turgut; Gumus, MetinIn this study, an experimental investigation was performed to reveal combustion and emission characteristics of common-rail four-cylinder diesel engine run with CH4, CO2 and H-2 mixtures. The engine pistons were thermally coated with zirconia and Ni-Al bond coat by plasma spray method. With a small amount of the pilot diesel, port fuelled methane (100% CH4), synthetic biogas (80% CH4 + 20% CO2), and hydrogen presented (80% CH4+10% CO2+10% H-2) mixtures were used as main fuel at different loads (50 Nm, 75 Nm, and 100 Nm) at a constant speed of 1750 min(-1). Comparative analysis of the combustion (cylinder pressure, PRR, HRR, CHR, ringing intensity, CA10, CA50, and CA90), BSFC, and emissions (CO2, HC, NOx, smoke, and oxygen) at the various engine loads with and without piston coating was made for all fuel combinations. It was found that coating the engine pistons enhanced the examining combustion characteristics, whereas it slightly changed BSFC and most of the emissions. As compared to the sole diesel fuel, the gaseous fuel operations showed higher in-cylinder pressure, PRR, and ringing intensity values, earlier combustion starting and CAs, and lower diesel injection pressure at the same engine operating conditions. Dramatic increase in the ringing intensity was particularly found by the hydrogen introduced mixture under the tests with coated piston. HC and CO2 emissions increased in operation with the synthetic biogas; however, hydrogen introduction reduced HC emissions by 4.97-30.92%, and CO2 emissions by 5.16-10%. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.Publication Metadata only Effects of hydrogen enrichment on combustion characteristics of a CI engine(PERGAMON-ELSEVIER SCIENCE LTD, 2017) DEMİR, ABDULLAH; Yilmaz, I. T.; Demir, A.; Gumus, M.In this study a comprehensive investigation of combustion (cylinder pressure, rate of pressure rise, ignition delay) and heat release (rate of heat release, cumulative heat release and center of heat release) parameters of a four cylinder, turbocharged, common rail compression ignition engine running with hydrogen addition was carried out. Hydrogen was send into intake manifold by using a mixing chamber. Flow rates of hydrogen were 20 lpm and 40 lpm for achieving constant speed of 1750 rpm at 50 Nm, 75 Nm and 100 Nm engine loads (EL). Results showed that maximum cylinder pressures (CPs), rate of pressure rises (ROPRs) and ignition delays (IDs) raised, rate of heat releases (ROHRs) decreased and combustion durations (CDs) extended with hydrogen addition. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.