Higher fuel economy associated with lower emissions of diesel engines cannot be achieved with conventional low-pressure injection systems. However high-pressure CRDI facilitated diesel engines with electronic control systems can overcome the twin problems of higher emissions of smoke and nitric oxide with acceptable higher brake thermal efficiency as well. Further use of both high-octane fuels like petrol, ethanol as manifold injected fuels along with high pressure CRDI injected high cetane fuels like diesel, biodiesel can successfully overcome the drawbacks of diesel engine emissions. In this direction a newer concept of RCCI operated modified diesel engine was developed in house and was powered with both high octane and high cetane fuels. Comprehensive experiments were conducted on the RCCI engine to obtain its performance, emission characteristics fueled with selected fuel combinations. From the results for B20 and gasoline operation it was concluded that, injection of 10% gasoline drastically reduces the nitric oxide by 6.67% and soot emission by 4.52% compared to diesel mode. However, there was penalty of high hydrocarbon and carbon monoxide emissions by 12.5% and 7.6% respectively. (C) 2020 Elsevier Ltd. All rights reserved.