Effect of Injector Opening Pressure on Performance, Emission and Combustion Characteristics of DI Diesel Engine Fueled with Diesel and Honne Oil Methyl Ester B.K. Venkanna a and C. Venkataramana Reddy b a Department of Mechanical Engineering, Basaveshwar Engineering College, Bagalkot 587102, Karnataka, India; 18venky18@gmail.com (for correspondence) b Guru Nanak Institute of Technology, Ibrahimpatnam, R.R. District 501506, Andhra Pradesh, India Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ep.10607 Honne oil methyl ester (HOME), a nonedible vegetable oil has remained as an untapped new possible source of alterna- tive fuel. The present research is aimed to investigate experi- mentally the performance, exhaust emission, and combustion characteristics of a DI diesel engine, when fueled with neat diesel (ND) and HOME. The injector opening pressure (IOP) is varied from 200 bar (manufacturer specified value) to 260 bar in steps of 20 bar. The combustion parameters of HOME (IOP 260 bar) are found to be very close to ND. For other IOPs, these combus- tion parameters deviated compared to ND. The performance (BTE, BSFC, and EGT) of HOME (IOP 260 bar) is almost the same as that of ND. For other IOPs, BTE is inferior compared to ND. The emissions (CO and SO) of HOME (IOP 260 bar) are dropped significantly compared to ND. HC emissions of HOME (IOP 240 bar) are slightly decreased, whereas for other IOPs, it is increased compared to ND. NO x emissions of HOME (IOP 200 to 260 bar) are slightly decreased. The reductions in exhaust emissions and increase in BTE made HOME (IOP 260 bar) a suitable alternative fuel for diesel fuel and thus could help in controlling air pollu- tion. Ó 2011 American Institute of Chemical Engineers Environ Prog, 00: 000–000, 2011 Keywords: diesel engine, biodiesel, emission, combustion, injector opening pressure INTRODUCTION DI diesel engines are fuel-efficient power plants for auto- motive applications because of their superior fuel economy over indirect injection engines. However, diesel engines suf- fered from high emissions of particle matter/smoke density and NO x , and there is inherent trade-off between them. Con- tinuing rise in prices, growing concern on environment from exhaust emissions, global warming, and threat of supply instabilities have led to a growing concern for alternative fuel (oxygenated fuels such as biodiesel, ethyl or methyl esters of vegetable oil/animal fats, and ethanol, etc.) for diesel engines throughout the world, more so in the petroleum importing countries like India. Biodiesel has higher cetane number [1, 2] (better ignition qualities), near zero aromatic and free sulphur [3]. The fatty acid composition of biodiesel derived from different vegeta- ble oils is not same [4]. Hence, the fuel properties of biodie- sel are not the same [4]. There are many methyl esters of veg- etable oils, which can be used as fuels in diesel engines. Most of these vegetable oil methyl esters were used in diesel engine without changing IOP. However, little literature is available on the use of biodiesels with different IOPs [5–8]. Many investigators [9, 10–15] reported that injector opening pressure (IOP) has a significance effect on the performance and formation of pollutants inside the DI diesel engine com- bustion. Alriksson et al. [10] reported that high charge air pressure and high injection pressure are important parame- ters for achieving low emissions. An increase of injection pressure is found to enhance the atomization, reducing fuel particle diameter at the nozzle out, resulting in more disper- sion of fuel particles resulting in turn in better vaporization and hence better mixing of air and fuel during the ignition delay period, HC and smoke level will reduce [11, 12]. Houn- talas et al. [13] found that the increment of injection pressure results to higher maximum rate of heat release and faster combustion (reduced duration). Higher differences are observed when increasing injection pressure from 1040 to 1200 bar and lower ones from 1200 to 1700 bar. Venkanna and Venkataramana used HO/diesel blend in DI diesel engine with increased IOP and increased injection rate and reported improved performance and emissions [14, 15]. Engine performance with biodiesel slightly goes down [16–18] or slightly goes up [1, 3, 19] compared with the ND. However, some studies have showed that biodiesel from veg- etable oil/waste vegetable/frying oils has little or no change in the diesel engine performance [20–22]. Ozsezen et al. [21] found that maximum torque obtained with the waste palm oil methyl ester and canola oil methyl ester (COME) bio-fuels was lower than that of ND. They also showed that peak cyl- inder gas pressure obtained with COME was similar to ND. Krishna and Nagarajan [23] reported that higher IOP improved emissions in turn performance. The chemical composition of vegetable oil helps in reduc- ing the emission of unwanted components when they are Ó 2011 American Institute of Chemical Engineers Environmental Progress & Sustainable Energy (Vol.000, No.00) DOI 10.1002/ep Month 2011 1