Influence of Injection Timing Variation on Combustion-Emission-Performance Aspects of Emulsified Plastic Oil-Run Compression Ignition Engine

This study investigates the influence of injection timing (IT) on combustion-emission-performance aspects of the compression ignition (CI) engine, running with emulsified plastic oil (EPO). The IT was advanced to 25 deg before the top dead center (bTDC) as well as retarded to 21 deg bTDC for the EPO-run engine, and the obtained results were compared with EPO and neat diesel-run engine at standard IT (23 deg bTDC). At full load, the peak cylinder pressure increased to 64.7 bar when the IT was advanced to 25 deg bTDC. The corresponding peak heat release rate also increased to 40.29 J/crank angle due to the advancement of IT in comparison with the standard IT. The brake-specific fuel consumption also improved at all loading conditions. However, the advancement of IT increased the nitrogen oxides (NOx) and temperature of exhaust gas slightly. In addition, 25 deg bTDC for EPO also reduced the unburnt hydrocarbon (HC), carbon monoxide (CO), and smoke emissions with respect to the standard IT. Largely, the advanced IT improved the majority of the engine characteristics for EPO except for the NOx, but that is also lower than diesel-run operation. Thus, 25 deg bTDC (for EPO) exhibits promising potential to be implemented in CI engines.