1 Effect of Fuel Injection Pressure and Injection 1 Timing of Karanja Biodiesel Blends on Fuel 2 Spray, Engine Performance, Emissions and 3 Combustion Characteristics 4 5 Avinash Kumar Agarwal a *, Atul Dhar a , Jai Gopal Gupta a , 6 Woong Il Kim b , Kibong Choi b , Chang Sik Lee b , Sungwook Park b 7 a Engine Research Laboratory a , Department of Mechanical Engineering, 8 Indian Institute of Technology Kanpur, Kanpur-208016, India 9 b Combustion Engine and Energy Conversion Laboratory b 10 School of Mechanical Engineering, College of Engineering, Hanyang University 11 Seoul 133-791, Republic of Korea 12 *Corresponding Author’s email: akag@iitk.ac.in 13 14 Abstract 15 In this investigation, effect of 10, 20 and 50% Karanja biodiesel blends on injection rate, 16 atomization, engine performance, emissions and combustion characteristics of common 17 rail direct injection (CRDI) fuel injection system were evaluated in a single cylinder 18 research engine with CRDI at 300, 500, 750 and 1000 bar fuel injection pressures at 19 different start of injection timings and constant engine speed of 1500 rpm. The 20 durationof fuel injection slightly decreased with increasing blend ratio of biodiesel 21 (Karanja Oil Methyl Ester: KOME) and significantly decreases with increasing fuel 22 injection pressure. The injection rate profile and sauter mean diameter (D32 ) of the fuel 23