Many researchers pointed out that the need of research in the areas of operating parameters so as to suit the higher proportion of biodiesel diesel blend in diesel engine without drop on its performance. The operating parameters such as compression ratio (CR), injection timing (IT) and injection pressure (IP) are effectively used in diesel engine for improving the performance and also reducing the exhaust emissions. Hence, in the present investigation an attempt has been made to investigate the effect of CR, IT and IP on the performance, combustion and emission characteristics of diesel engine using 20% proportion of biodiesel diesel blend (A20). Further, this paper also aims at to find out the optimum operating parameters. It was found from experimental investigation that at high of CR (19.5), IP (250 bar) and IT (33 degrees CA) showed improved BTE of approximately 7.14% than that of original operating parameters. Further, the HC, CO and smoke emissions were reduced by 4.78, 5.54 and 2.3% respectively than that of original operating parameters except NOx emission. (C) 2017 Elsevier Ltd. All rights reserved.