Experimental study on performance and emission control of a single cylinder four stroke tri charged RCCI engine with variable injection timing

The turbo-lag is a big problem associated with a turbocharger. A crank-driven supercharger consumes the output power of the engine and tends to produce more NOX. The problem related to the turbocharger and supercharger can be solved by employing the tri-charged technology, which combines a crank-driven supercharger, turbocharger, and electric-driven supercharger. The effect of tri-charged technology in combination with reactivity controlled at different injection timing has not been investigated. The present study performed experimental investigations on a single-cylinder, 4-stroke tri-charged reactivity controlled compression ignition (RCCI) engine. Investigations were carried out for super, turbo, twin, and tri-charged modes by varying the load from 2 kg to 12 kg with 2 kg intervals for all operating conditions. The RCCI engine was suitably modified for dual-fuel by incorporating a compressed natural gas (CNG) port fuel injection system with variable injection timing (2ms, 4ms, and 6ms). Different parameters were compared, namely brake power, brake-specific fuel consumption, thermal efficiency, volumetric efficiency, and emissions, and found significant improvement with the tri-charged mode. Tri-charged experimental results show considerable brake power improvement by 0.6 kW and thermal and volumetric efficiency improved by 1.82% and 7.1%, respectively, compared with a conventional (Naturally aspirated engine) engine. The emissions trends are adequately captured with the modification to tri-charged boosting, especially for HC, CO, and NOX, which are reduced to a great extent at a relatively low air-fuel equivalence ratio. Therefore, it can be concluded that the RCCI operating range extended with the tri-charged boost pressure, especially at low load capacity.