G.N. Kumar

Effect of Hydrogen Addition on Combustion and Emission Characteristics of High Speed Spark Ignition Engine- An Experimental Study

The present article aims at characterizing the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. The conventional carburetted SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline. The engine was maintained at a constant speed of 3000 rpm and wide open throttle position. The experimental results demonstrated that heat release rate and cylinder pressure were increased with the addition of hydrogen until 20%. The CO and HC emissions were reduced considerably whereas NOx emission was increased with the addition of hydrogen in comparison with pure gasoline engine operation.

Effect of injection pressure on the performance and emission characteristics of the CI engine using Vateria indica biodiesel

ABSTRACT Vateria indica Linn seeds were found to contain nearly 19% of oil/fat content. This fat is converted into biodiesel by a novel method by the authors at the biodiesel preparation facility at NITK, Surathkal, India. As biodiesel is a promising alternative fuel for petro diesel in compression ignition (CI) engines, this biofuel is tested in a single-cylinder diesel engine. The objective of this work is to find combustion, performance and emission characteristics of a CI engine with diesel and blends of V. indica biodiesel at 180, 200 and 220 bar injection pressures. Blending is done in volumetric ratios of 10%, 15%, 20% and 25% of biodiesel with diesel which are called as B10, B15, B20 and B25. The idea of increasing fuel injection pressure is to promote atomisation and full penetration into the combustion chamber leading to better combustion. Blend B25 showed best thermal efficiency of the order of 33.03% and the least NOX emission of 1047 ppm at 220 bar injection pressure at 75% load.

CFD Simulation of a Common Rail Diesel Engine with Biobutanol-Diesel Blends for Various Injection Timings

Turmoil in petroleum market and stringent environment guidelines, accelerated the research in the field of alternative fuels for Internal Combustion engines. Biofuel is gaining venerable importance as it is renewable and substitute to the fossil fuels. This study investigates the potential of butanol fueling in a diesel engine. In this computational fluid dynamics (CFD) simulation, the effect of injection timing and butanol-blends on the exhaust emission and combustion characteristics of common rail direct injection (CRDI) engine is studied. The simulation is carried out for wide range of injection timings from 0° to 30° BTDC, and butanol-diesel blends from, 10, 20, and 30% at very high injection pressure (~90 MPa). Three dimensional computational code is implemented to solve conservation equations based on finite volume method. SIMPLE (semi-implicit method for pressure-linked equations) algorithm is used to obtain velocity and pressure at each computational cell. The flow within the combustion chamber is simulated using the k-ξ-f turbulence model. Extended coherent flame model-3 zone (ECFM3Z) is employed to carry out combustion analysis. In-cylinder fuel injection is studied using blob injection which assumes orifice diameter as fuel droplet diameter. As the percentage of the butanol blend increases, NO, CO increases and soot formation decrease as compare to neat diesel. Optimum injection timing obtained for maximum indicated thermal efficiency for 10–30% blend is 27° BTDC, whereas, for neat diesel it is 24° BTDC. Obtained results are validated with available literature data and found good agreement.

Influence of spark timing on the performance and emission characteristics of gasoline–hydrogen-blended high-speed spark-ignition engine

Abstract This article experimentally investigates the effect of spark timing on performance and emission characteristics of high-speed spark-ignition (SI) engine operated with different hydrogen–gasoline fuel blends. For this purpose, the conventional carbureted SI engine is modified into an electronically controllable engine, wherein an electronically controllable unit was used to control the ignition timings and injection duration of gasoline. The tests were conducted with different spark timings at the wide open throttle position and 3000 rpm engine speed. The experimental results demonstrated that brake mean effective pressure and engine brake thermal efficiency increased first and then decreased with the increase in spark advance. Peak cylinder pressure, temperature and heat release rate were increased until 20% hydrogen addition and with increased spark timings. NOx emissions were continuously increased with the increment in both spark timings and hydrogen addition, whereas hydrocarbon emissions were increased with spark timings but decreased with hydrogen addition. CO emissions were reduced with the increase in spark timing and hydrogen addition.

Performance and Emission Analysis of a Single Cylinder CI Engine using Simarouba glauca Biodiesel

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.

Effect of bioethanol–diesel blends, exhaust gas recirculation rate and injection timing on performance, emission and combustion characteristics of a common rail diesel engine

ABSTRACT This investigation is focused on the effect of exhaust gas recirculation (EGR) and injection timing on the performance, combustion and exhaust emission characteristics of common rail direct injection (CRDI) engine fueled with bioethanol-blended diesel using computational fluid dynamics (CFD) simulation. Simulation is carried out for various EGR rates (0, 10, 20 and 30%), two different injection timings, and two different bioethanol–diesel blends (10 and 20%) at injection pressure. The equivalence ratio is kept constant in all the cases of bioethanol–diesel blends. The results indicate that the mean CO formation and ignition delay increase, whereas mean NO formation and in-cylinder temperature decrease, with increase in the EGR rate. Further, with an increase in percentage of the bioethanol blends, CO and soot formation decrease as compared to neat diesel. A significant increase in in-cylinder pressure (15%) is found at 14° before top dead centre (BTDC) compared to 9° BTDC, which leads to an increase in indicated thermal efficiency of 4% for neat diesel at 30% EGR. In the present study, maximum indicated thermal efficiency is obtained in the case of 10 and 20% bioethanol–diesel blend, and remains constant for all EGR rates considered in the study. Obtained results are validated with the available literature data and indicate good agreement.