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A Ramesh
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A Ramesh
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A Ramesh
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Ramesh, a.
Ramesh, Asvathanarayanan
Ramesh, A.
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53 results
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- PublicationA simple approach to calculate the heat release rate in a two-stroke spark ignition engine(01-01-2001)
;Reddy, K. A.A method to estimate the heat release rate of a two-stroke spark ignition engine using cylinder pressure data, the measured temperature of the gases in the exhaust manifold and the mass of fuel air mixture supplied to the engine has been developed. Experiments have been conducted on a single cylinder air cooled two-stroke spark ignition engine to obtain the average pressure crank angle data and other inputs needed for the calculation. A standard scavenging model has been used to calculate the masses of the trapped fresh mixture and exhaust gas. The heat transfer and gas properties are obtained using well-known equations. Trapped exhaust gas temperature, trapped charge temperature, trapped masses and heat release rate are obtained using the developed procedure. These results are compared with the results obtained by using a simple scheme where a polytropic index of 1.35 has been assumed. It is seen that the effect of heat transfer on the heat release rate is small if the gas temperature is properly evaluated and used in the calculations. - PublicationLow cost Engine Management System (EMS) for the cost sensitive two-wheeler application: Idle speed and A/F ratio control using PID and fuzzy logic control algorithms(18-06-2008)
; In this work an Engine Management System (EMS) using a low cost 8-bit microcontroller specifically for the cost sensitive small two-wheeler application was designed and developed. Only the Throttle Position Sensor (TPS) and the cam position sensor (also used for speed measurement) were used. A small capacity 125CC four stroke two-wheeler was converted into a Port Fuel Injected (PFI) engine and was coupled to a fully instrumented Eddy Current Dynamometer. Air-fuel ratio was controlled using the open loop, lookup-table [speed (N) and throttle (α)] based technique. Spark Time was controlled using a proportional / fuzzy logic based close loop control algorithm for the idle speed control to reduce fuel consumption and emissions. Test results show a significant improvement in engine performance over the original carbureted engine, in terms of fuel consumption, emissions and idle speed fluctuations. The Proportional controller resulted in significantly lower speed fluctuations and HC / CO emissions than the fuzzy logic controller. Though the fuzzy logic controller resulted in low cycle by cycle variations than the original carbureted engine, it leads to significantly higher HC levels. The performance fuzzy logic can be improved by modifying the membership function shapes with more engine test data. Copyright © 2007 by ASME. - PublicationUse of diethyl ether along with water-diesel emulsion in a di diesel engine(01-01-2002)
;Subramanian, K. A.Experimental investigations were carried out to assess the effect of using diethyl ether to improve performance & emissions of a DI diesel engine running on water-diesel emulsion. The water-diesel ratio was 0.4:1 (by weight) and diethyl ether percentages of 5, 10 & 15 by weight were tried. The optimum quantity of diethyl ether was chosen as 10% based on emissions. It was found that diethyl ether, when added to water-diesel emulsion can significantly lower NOx and smoke levels without adverse effect on brake thermal efficiency. High HC & CO levels which are problems with water-diesel emulsions, can be significantly lowered with the addition of diethyl ether particularly at high outputs. Ignition delay and maximum rate of pressure rise at full load are also reduced. Even at part load the addition of the diethyl ether can improve the performance as compared to neat water-diesel emulsion without any adverse effect on NOx emission. However, the HC and CO levels are still higher than diesel operation. In general, it is concluded that diethyl ether can be used to solve some of the problems associated with the use of water diesel emulsions in a diesel engine Copyright © 2002 SAE International. - PublicationExperimental investigations on a jatropha oil methanol dual fuel engine(01-01-2001)
;Kumar, M. Senthil; Nagalingam, B.Use of vegetable oils in diesel engines results in increased smoke and reduced brake thermal efficiency. Dual fuel engines can use a wide range of fuels and yet operate with low smoke emissions and high thermal efficiency. In this work, a single cylinder diesel engine was converted to use vegetable oil (Jatropha oil) as the pilot fuel and methanol as the inducted primary fuel. Tests were conducted at 1500 rev/min and full load. Different quantities of methanol and Jatropha oil were used. Results of experiments with diesel as the pilot fuel and methanol as the primary fuel were used for comparison. Brake thermal efficiency increased in the dual fuel mode when both Jatropha oil and diesel were used as pilot fuels. The maximum brake thermal efficiency was 30.6% with Jatropha oil and 32.8% with diesel. Smoke was drastically reduced from 4.4 BSU with pure Jatropha oil operation to 1.6 BSU in the dual fuel mode. Hydrocarbon and carbon monoxide emissions were higher in the dual fuel mode with both fuels. Heat release pattern in the case of neat Jatropha oil operation showed a smaller premixed combustion phase and a larger diffusion combustion phase as compared to diesel operation. These phases were not distinguishable in the dual fuel mode. Copyright © 2001 Society of Automotive Engineers, Inc. - PublicationUse of hydrogen to enhance the performance of a vegetable oil fuelled compression ignition engine(01-01-2003)
;Senthil Kumar, M.; Nagalingam, B.Use of vegetable oils in unmodified diesel engines leads to reduced thermal efficiency and increased smoke levels. In this work, experiments were conducted to evaluate the performance while using small quantities of hydrogen in a compression ignition engine primarily fuelled with a vegetable oil, namely Jatropha oil. A single cylinder water-cooled direct-injection diesel engine designed to develop a power output of 3.7 kW at 1500 rev/min was tested at its rated speed under variable load conditions, with different quantities of hydrogen being inducted. The Jatropha oil was injected into the engine in the conventional way. Results indicated an increase in the brake thermal efficiency from 27.3% to a maximum of 29.3% at 7% of hydrogen mass share at maximum power output. Smoke was reduced from 4.4 to 3.7 BSU at the best efficiency point. There was also a reduction in HC and CO emissions from 130 to 100 ppm and 0.26-0.17% by volume respectively at maximum power output. With hydrogen induction, due to high combustion rates, NO level was increased from 735 to 875 ppm at full output. Ignition delay, peak pressure and maximum rate of pressure rise were also increased in the dual fuel mode of operation. Combustion duration was reduced due to higher flame speed of hydrogen. Higher premixed combustion rate was observed with hydrogen induction. Comparison was made with diesel being used as the pilot fuel instead of vegetable oil. In the case of diesel the brake thermal efficiency was always higher. At the optimum hydrogen share of 5% by mass, the brake thermal efficiency went up from 30.3-32%. Hydrocarbon, carbon monoxide, smoke emission and ignition delay were also lower with diesel as compared to vegetable oil. Smoke level decreased from 3.9 to 2.7 BSU with diesel as pilot at the optimum hydrogen share. Peak pressure, maximum rate of pressure rise, heat release rate and NO levels were higher with diesel than Jatropha oil. On the whole, it is concluded that induction of small quantities of hydrogen can significantly enhance the performance of a vegetable (Jatropha) oil/diesel fuelled diesel engine. © 2003 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved. - PublicationHCCI Engine Operation with Acetylene the Fuel(09-01-2008)
;Swami Nathan, S.; The homogeneous charge compression ignition (HCCI) engines emit low levels of smoke and NOx emissions. However, control of ignition, which is mainly controlled by fuel composition, the equivalence ratio and the thermodynamic state of the mixture, is a problem. In this work, acetylene was as the fuel for operating a compression ignition engine in the HCCI mode at different outputs. The results of thermal efficiency and emissions have been compared with base diesel operation in the (compression ignition) CI mode. The relatively low self ignition temperature, wide flammability limits and gaseous nature were the reasons for selecting this fuel. Charge temperature was varied from 40 to 110°C. Thermal efficiencies were almost equal to that of CI engine operation at the correct intake charge temperature. NO levels never exceeded 20 ppm and smoke levels were always lower than 0.1 BSU. HC emissions were higher and were sensitive to charge temperature and output. However, investigations are required to further extend the operating range of acetylene HCCI operation. On the whole this work demonstrates that acetylene can be considered as a HCCI engine fuel. - PublicationOn the effect of GDI injector configuration on charge preparation(01-01-2009)
;Bejoy, M. D.; A Gasoline Direct Injection (GDI) engine typically operates on multiple fuel-preparation modes. In general, at higher loads a homogeneous mixture is favoured whereas a stratified mixture is preferred at part and low load conditions. This is usually achieved by altering the injection timing with respect to load and speed. In this paper the effect of injector configuration on the mixing process has been studied systematically. Two different injector configurations are considered, one with a central-hole injection and other with a 6-hole injection. The objective is to investigate the effect of initial fuel distribution inside the engine cylinder on charge preparation at the onset of ignition. This study also aims to explore a better solution for mixing in GDI engines by optimizing the GDI injector for both stratified and homogeneous mode of operations. An engine with a pentroof combustion chamber with centrally mounted injector and upright straight intake port and flat piston is selected. The computation begins from the start of the induction process and continued till the point of ignition. The dynamics of the mixing process is studied by grouping the in-cylinder charge in different bins in terms of the equivalence ratio. The temporal variation of the fraction of the mixture in different bins is studied as a function of time to understand the dynamics of the mixing process. Results from the parametric study indicate the possibility of switching the modes of mixing with respect to the operating conditions. - PublicationLOW COST ENGINE MANAGEMENT SYSTEM (EMS) FOR THE COST SENSITIVE TWO-WHEELER APPLICATION: IDLE SPEED AND A/F RATIO CONTROL USING PID AND FUZZY LOGIC CONTROL ALGORITHMS(01-01-2007)
; In this work an Engine Management System (EMS) using a low cost 8-bit microcontroller specifically for the cost sensitive small two-wheeler application was designed and developed. Only the Throttle Position Sensor (TPS) and the cam position sensor (also used for speed measurement) were used. A small capacity 125CC four stroke two-wheeler was converted into a Port Fuel Injected (PFI) engine and was coupled to a fully instrumented Eddy Current Dynamometer. Air-fuel ratio was controlled using the open loop, lookup-table [speed (N) and throttle (α)] based technique. Spark Time was controlled using a proportional / fuzzy logic based close loop control algorithm for the idle speed control to reduce fuel consumption and emissions. Test results show a significant improvement in engine performance over the original carbureted engine, in terms of fuel consumption, emissions and idle speed fluctuations. The Proportional controller resulted in significantly lower speed fluctuations and HC / CO emissions than the fuzzy logic controller. Though the fuzzy logic controller resulted in low cycle by cycle variations than the original carbureted engine, it leads to significantly higher HC levels. The performance fuzzy logic can be improved by modifying the membership function shapes with more engine test data. - PublicationOperation of a compression ignition engine on diesel-diethyl ether blends(01-12-2002)
;Subramanian, K. A.A detailed investigation on the effect of using diesel-diethyl ether blends in a direct injection diesel engine has been carried out. Blends with 5, 10 & 15% by weight of diethyl ether were tested. The optimum quantity of diethyl ether was found as 10% based on the thermal efficiency. Tests were also conducted with the optimum quantity at an advanced injection timing. With this timing, the blend decreased the smoke & CO level drastically at all loads and increased the brake thermal efficiency at high loads with out affecting NO emissions. It also increased the peak heat release rate, peak pressure and maximum rate of pressure rise. It was concluded that 10% blend with injection timing slight advanced than base diesel operation is suitable. - PublicationParametric studies for improving the performance of a Jatropha oil-fuelled compression ignition engine(01-10-2006)
;Narayana Reddy, J.A single cylinder, constant speed, direct injection diesel engine was operated on neat Jatropha oil. Injection timing, injector opening pressure, injection rate and air swirl level were changed to study their influence on performance, emissions and combustion. Results have been compared with neat diesel operation. The injection timing was varied by changing the position of the fuel injection pump with respect to the cam and injection rate was varied by changing the diameter of the plunger of the fuel injection pump. A properly oriented masked inlet valve was employed to enhance the air swirl level. Advancing the injection timing from the base diesel value and increasing the injector opening pressure increase the brake thermal efficiency and reduce HC and smoke emissions significantly. Enhancing the swirl has only a small effect on emissions. The ignition delay with Jatropha oil is always higher than that of diesel under similar conditions. Improved premixed heat release rates were observed with Jatropha oil when the injector opening pressure is enhanced. When the injection timing is retarded with enhanced injection rate, a significant improvement in performance and emissions was noticed. In this case emissions with Jatropha oil are even lower than diesel. At full output, the HC emission level is 532 ppm with Jatropha oil as against 798 ppm with diesel. NO level and smoke with Jatropha oil are, respectively 1162.5 ppm and 2 BSU while they are 1760 ppm and 2.7 BSU with diesel. © 2005 Elsevier Ltd. All rights reserved.