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Srīperumbūdūr, India

Rajesh Kumar B.,Jeppiaar Institute of Technology | Saravanan S.,Sri Venkateswara College of Engineering
Fuel | Year: 2015

In this work, the effects of blending n-pentanol, a second generation biofuel with diesel on the performance and emission characteristics of a diesel engine under exhaust gas recirculation (EGR) conditions are investigated. Tests were performed on a single-cylinder, constant-speed, un-modified, direct-injection diesel engine using four n-pentanol/diesel blends: 10%, 20%, 30% and 45% (by volume). The possibility of using a high pentanol/diesel blend (45%) was also explored with an objective to maximize the renewable fraction in the fuel. Three EGR rates (10%, 20% and 30%) were utilized with an intention to reduce the high nitrogen oxides (NOx) that were prevalent at high engine loads using these blends. Test results showed that increasing EGR rates brought down NOx emissions by up to 41% at medium load and 33.7% at high load. Smoke opacity hardly increased up to 20% EGR rate and beyond that it increased for all blends. It was found that simultaneous reduction of NOx and smoke emissions can be achieved using the combination of pentanol/diesel blends and a medium EGR rate (20-30%) with a small drop in performance. Increase in hydrocarbons (HC) and slight increase in carbon-monoxide (CO) emissions were experienced with all blends when compared to diesel fuel under EGR conditions. It was concluded that 45% pentanol/diesel blends can be used in diesel engines without any modifications and without causing any visible damage to the engine parts subject to long-term durability tests. © 2015 Elsevier Ltd. All rights reserved.

Rajesh Kumar B.,Jeppiaar Institute of Technology | Saravanan S.,Sri Venkateswara College of Engineering
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy | Year: 2016

Iso-butanol is a second generation biofuel that has the potential to improve energy security and mitigate harmful pollutants in reciprocating engines. The present study investigates the effect of iso-butanol addition to diesel fuel on performance and emissions of a single cylinder direct-injection diesel engine with exhaust gas recirculation (EGR). For this objective, four iso-butanol/diesel blends containing 10%, 20%, 30%, and 40% were prepared by volume basis and tested in the engine under three EGR rates: 10% to 30% (at increments of 10%) with the combination of two injection timings: 23° and 21° crank angle (CA) before top dead center (bTDC). Experimental results showed that the combination of 30% EGR rate, 40% iso-butanol addition (ISB40) and retarded injection timing by 2° CA bTDC simultaneously reduced NOx emissions from 1284 to 749 ppm and smoke opacity from 20.7% to 1.9% with a slight drop in performance. It was found that higher iso-butanol/diesel blends require higher EGR levels to attain optimum levels of smoke and NOx emissions. Both hydrocarbon (HC) and carbon-monoxide (CO) emissions presented an increasing trend at escalating EGR rates. At retarded injection timing, ISB40 blend presented decreased HC emissions, increased CO emissions with a slight drop in performance compared to its injection at original timing. © Institution of Mechanical Engineers.

Rajesh Kumar B.,Jeppiaar Institute of Technology | Saravanan S.,Sri Venkateswara College of Engineering
Renewable and Sustainable Energy Reviews | Year: 2016

Biofuels have grabbed the attention of engine researchers ever since the oil-crisis and escalating costs of petro-chemicals cropped up in the '70s. Ethanol and methanol were the most widely researched alcohols in IC engines. However, the last decade has witnessed significant amount of research in higher alcohols due to the development of modern fermentation processes using engineered micro-organisms that improved yield. Higher alcohols are attractive second/third generation biofuels that can be produced from sugary, starchy and ligno-cellulosic biomass feedstocks using sustainable pathways. The present work reviews the current literature concerning the effects of using higher alcohols ranging from 3-carbon propanol to 20-carbon phytol on combustion, performance and emission characteristics of a wide range of diesel engines under various test conditions. The literature is abound with evidence that higher alcohols reduce carcinogenic particulate emissions that are prevalent in diesel engines. NOx emissions either increased or decreased based on the domination of either cetane number or heat of evaporation. Brake specific fuel consumption (BSFC) of the engine usually suffered due to low energy content of alcohols. A notable feature is that the combination of higher alcohols (like butanol or pentanol), high exhaust gas recirculation (EGR) rates and late injection timing enabled low temperature combustion (LTC) in diesel engines that can simultaneously reduce smoke and NOx emissions with improved engine efficiency. It can be concluded that higher alcohols reduce smoke emissions with their fuel-borne oxygen; enhance air/fuel mixing by offering long ignition delay and eventually replace fossil diesel (partially or wholly) to enable a clean and efficient combustion in compression-ignition engines. The chief thrust areas include developing mutant strains with higher yield, higher tolerance to toxic inhibition and low-cost substrates for fermentation. Further work is required in stipulating optimum blend-fuel characteristics and ensuring the long-term durability of the engines using these fuels. © 2016 Elsevier Ltd. All rights reserved.

Rajesh Kumar B.,Jeppiaar Institute of Technology | Rajesh Kumar B.,Sri Venkateswara College of Engineering | Saravanan S.,Sri Venkateswara College of Engineering
Fuel | Year: 2016

This study investigates the potential use of dimethyl carbonate (DMC), a green, non-toxic and low-reactive biofuel to enable partially premixed low temperature combustion (PPLTC) mode in a DI diesel engine. PPLTC is an intermediate combustion strategy between conventional diesel combustion and homogenous charge compression ignition (HCCI) combustion which provides sufficiently long ignition delay for fuel/air to pre-mix inside the cylinder and to eventually restrain harmful smoke and NOx emissions. The engine was fueled with 15% by vol. of DMC/diesel blend (DMC15) and the combustion, performance and emission characteristics were examined under high loads with charge-dilution and combustion-phasing controlled by employing EGR (0-30%) and adjusting the injection timing (25-21°CA bTDC). Experimental results revealed that DMC15 exhibited better performance when the injection timing is advanced from 21°to 25°CA bTDC at the expense of emissions. Nevertheless DMC15 injected at 21°CA bTDC under 30% EGR experienced longest ignition delay and lowest peaks in pressure and heat release rate (HRR) to achieve a maximum simultaneous reduction of NOx emissions (▾46.1%) and smoke opacity (▾64.7%) respectively with a small drop in performance (▾11.8%). Both total hydrocarbons (THC) and carbon-monoxide (CO) emissions increased at intensified EGR rates. © 2016 Elsevier Ltd.

Yuvarajan D.,Jeppiaar Institute of Technology | Venkata Ramanan M.,Anna University
Journal of Mechanical Science and Technology | Year: 2016

Transesterification of fatty acid using the application of ultrasound stirring and microwave irradiation has been used of late for biodiesel production from various vegetable oil and animal fats. However analysis on influence of these techniques on performance, combustion and emission aspects has received little attention. In this work, transesterification of mustard oil with methanol was performed using ultra sound stirring (42 kHz /170 W, 80 W) and microwave irradiation (230v AC, 50 Hz, 900 W). Reaction time, conversion rate, fuel properties, performance, emission and combustion characteristics were compared with conventional transesetrification. Results indicated that Mustard oil methyl ester subjected to ultrasonication and microwave irradiation (MOMESUM) has 5.71% more yield than conventional transesterification process. It was also observed that BTE for MOMESUM is improved by 5.84% with 5.14% reduction in BSFC when compared to MOME. CO, HC, NOx and Smoke emission was found to decrease by 11.39%, 3.81%, 7.99% and 5.3% respectively for MOMESUM. © 2016, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

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