# Introduction egulations to reduce NOx emissions continue to become more and more stringent year after year. Since high cylinder temperatures cause NOx, it can be reduced by lowering the cylinder temperatures. Reduced cylinder temperatures can be achieved by reducing the amount of oxygen by re-circulating a part of exhaust gases back in to the cylinder, which inhibits the combustion process. In the present work, engine tests are conducted with 10%, 15% and 20% EGR along with Grooved piston with 9 grooves with Diamond mesh cut configuration (Appendix-A), and their effect on performance and emissions are studied. ? EGR10 :10% of exhaust gas circulation. ? EGR15 :15% of exhaust gas circulation. ? EGR20 : 20% of exhaust gas circulation. # a) Test Engine A single cylinder air-cooled four stroke, direct injection (DI) compression ignition diesel engine is chosen for the present investigation. The detailed engine specifications are provided in Appendix-B. The recommended injection timing by the manufacturer is 28 0 bTDC (static) and the nozzle opening pressure of 190 bar. Author ?: Associate prof. Dept. of Mechanical Engineering, MREC (Autonomous), Hyderabad, India. e-mail: prathibhaseenu@gmail.com Author ?: Professor, Department of Mechanical Engineering, JNTUACE, Anantapur, India. # II. # Performance Parameters The performance parameters like brake thermal efficiency, brake specific fuel consumption and exhaust gas temperature are discussed below. # a) Brake Thermal Efficiency The variations of brake thermal efficiency with power output for the piston with different configurations are shown in Figure 1. The brake thermal efficiency for normal engine at 3/4 of rated load is 26%. It can be observed that the engine with EGR10, EGR15 and EGR20 give thermal efficiencies of 28.1%, 27.9 and 27.6%, respectively, at 3/4 of rated load. From Figure, it is inferred that the brake thermal efficiencies are increasing with an increase in brake power for configurations that are under consideration. It is also observed that there is a gain of 7.4% with EGR20 for normal engine. # b) Brake Specific Fuel Consumption The variations of brake specific fuel consumption with brake power for different configurations are shown in Figure 2. The brake specific fuel consumption for normal engine at 3/4 of rated load is 0.34 kg/kW-hr. It can be observed that the engine with EGR10, EGR15 and EGR20 give brake specific fuel consumption of 0.31 kg/kW-hr, 0.32 kg/kW-hr and 0.33 kg/kW-hr respectively, at 3/4 of rated load. From Figure 4.20, it is inferred that the brake specific fuel consumption are increasing with an increase in brake power for configurations that were under consideration. It is also observed that the EGR20 has a reduction of 2.94% of fuel consumption for normal engine. # c) Exhaust Gas Temperature The comparison of exhaust gas temperature with brake power is shown in Figure 3. The exhaust gas temperatures are higher for EGR10 compared to that of EGR20. The exhaust gas temperature for EGR20 varies from 145°C at no load to 328°C at 3/4 of rated load. For EGR 10, the exhaust gas temperature varies from 149°C at no load to 330°C at 3/4 of rated load whereas for normal engine it varies from 151°C at no load to 341°C at 3/4 of rated load. It is observed that there is a decrease of 3.8% for EGR20 at normal engine. Year 2014 III. # Combustion Parameters The combustion parameters like ignition delay and peak pressure are discussed below. # ume XIV Issue II Version I a) Ignition Delay The variation of ignition delay with brake power for different configurations is shown in Figure 4. It is inferred that ignition delay, decreases with an increase in brake power for almost all configurations. With an increase in brake power, the amount of fuel being burnt inside the cylinder is increased and subsequently the temperature of in-cylinder gases is increased. This may lead to reduced ignition delay in all configurations. However, the ignition delay for diesel fuel was lower under EGR10, EGR15 and EGR20 configurations than the normal engine. It is observed that the ignition delay of EGR10, EGR15 and EGR20 are 10.3o CA, 10.5o CA and 10.8o CA at 3/4 of rated load respectively. The reduction in the ignition delay of EGR20 is about 1.8% at 3/4 of rated load for normal engine. # b) Cylinder Peak Pressure The variations of peak cylinder gas pressure with brake power for different configurations are given in Figure 5. It is observed that the peak pressure is increased with an increase in brake power. The peak pressures for EGR10, EGR15 and EGR20 are 57.4 bar, 57.8 bar and 58.4 bar at 3/4 of rated load respectively. There is a decrease of 2.7 % in peak pressure for normal engine. IV. # Emission Parameters The emission parameters like smoke density, NOx emission hydrocarbon and carbon monoxide emission are discussed below. # a) Smoke Density Smoke is solid soot particles suspended in exhaust gas. The comparison of smoke level with brake power is shown in Figure 6. It can be observed that smoke increases with increase in brake power. The smoke number for EGR10, EGR15 and EGR20 are 2.35 BSU, 2.38 BSU and 2.4 BSU respectively, whereas for normal engine it is 2.46 BSU. Due to the complete combustion of diesel with excess air, the smoke emissions are marginal. At 3/4 of the rated load, the smoke emissions for EGR20 are reduced by about 2.4 % for normal engine. # b) Nitrogen Oxide Emissions The comparison of NOx emission with brake power for different configurations is shown in Figure 7. It can be observed from the figure that NOx emission increases with increase in turbulence in the cylinder because of high temperature. The NOx emissions for EGR10, EGR15 and EGR20 are 540 ppm, 520 ppm and 490 ppm respectively, whereas for normal engine it is 562 ppm. The NOx emissions are lower of 13 % for EGR20 for normal at 3/4 of rated load. # c) Hydrocarbon Emissions The comparison of Hydrocarbon emission with brake power is shown in Figure 8. The HC emissions for EGR10, EGR15 and EGR20 are 71 ppm, 72 ppm and 74 ppm respectively, whereas for normal engine it is 78.2 ppm. The HC emissions are lower of 5.4% for EGR20 for normal at 3/4 of rated load. # d) Carbon Monoxide Emissions The comparison of Carbon monoxide emission with brake power is shown in Figure 9. The CO emissions for EGR10, EGR15 and EGR20 are 0.155, 0.162 and 0.165 % volume respectively, whereas for normal engine it is 0.17 % volume. The CO emissions are lower of 2.9% for EGR20 for normal engine at 3/4 of rated load. 123456789![Figure 1 : Comparison of Brake thermal Efficiency with different percentages of EGR](image-2.png "Figure 1 :Figure 2 :Figure 3 :Figure 4 :Figure 5 :Figure 6 :Figure 7 :Figure 8 :Figure 9 :") © 2014 Global Journals Inc. (US) ## Appendix-A ## Specifications of Diesel Engine Appendix-B ## Conclusions The following conclusions are drawn based on the effect of EGR in the cylinder and the results are compared to normal engine at 3/4 of the rated load. ? The brake thermal efficiency is increased by about 7.4%. ? The improvement in brake specific fuel consumption is about 2.9%. ? The exhaust gas temperature is lower and it is 3.8% less than normal engine. ? The reduction in the ignition delay is about 1.82%. ? The peak cylinder pressure is decreased by about 2.7%. ? The smoke emission in the engine is reduced by about 2.4% ? The maximum reduction in NOx emissions are about 13%. ? The maximum reduction in HC emissions are about 5.4%. ? The carbon monoxide emissions are found to be reduced by about 2.9%. From the investigation, it is evident that in the single cylinder D.I diesel engine, the combination of karanja bio-diesel with EGR20 and piston with nine grooves give better performance and reduced emissions. ## Global Journals Inc. (US) Guidelines Handbook 2014 www.GlobalJournals.org * Design of an inlet track of a Small I. C. engine for swirl enhancement JorgeMartins StijncoeneSenhorinhateixeira Proceedings of COBEM 2009 20th International Congress of Mechanical Engineering COBEM 2009 20th International Congress of Mechanical Engineering November 15-20, 2009 * Diesel engine exhaust gas recirculation --a review on advanced and novel concepts MingZheng A GrahamTReader B JGaryHawley C Energy Conversion and Management 45 2004 * Effect of exhaust gas recirculation on some combustion characteristics of dual fuel engine YEMohamed Selim Energy Conservation and Management 44 2003 * Experimental investigation of control of NOx emissions in bio-diesel-fueled compression ignition engine, Renewable Energy DeepakAgarwal AvinashShailendrasinha Kumar Agarwal 2005 * Prediction of cylinder pressure in a diesel engine using an improved mixture formation model KNAbadalla Sudan engineering Society journal Jan 1997 * Internal Combustion Engine WPulkrabek 2004 Prentice Ha11 New Jersey * Effect of cooling the recirculated exhaust gases on diesel engine emissions HNidal Abu -Hamdeh Journal of Energy Conservation and Management 44 2003 * Effects of swirl/tumble motion on incylinder mixture formation in a lean-burn engine TUrushihara TNakada AKakuhou YTakagi SAE 961994 1996 * Turbulent Air Flow in the Combustion Bowl of a D. I. Diesel Engine and Its Effect on Engine Performance" SAE Paper: 790040 Brandl 1979 * A Study of Abnormal Wear in Power Cylinder of Diesel Engine with EGR -Wear Mechanism of Soot Contaminated in Lubricating Oil EKazuyaIshiki ShinjiOshida MasaakiTakiguchi SAE: Proceedings of SAE 2000 World Congress SAE Technical Paper March 2000. 2000-01-0925, 2000