Energy and exergy analysis of the dual-fuel RCCI engine by ozone-assisted combustion of a lean mixture

An experimental investigation was carried out to explore the effects of ozone on the energy and exergy fractions in a single-cylinder light-duty Ricardo E/6 engine. This study undertook CNG that epitomizes the premixed low-reactivity fuel and diesel as the high-reactivity fuel. Measurements were taken for ozone additions of 0, 50, 100, 200, 250, 300, and 400 ppm, constant CNG-to-diesel energy ratio of 4, and the lambda number of 3.5. The results suggest that the increased seeded ozone augments energy and exergy efficiency. The growth rate at 0.26%, 1.85%, 3.00%, and 5.63% levels were derived in energy efficiencies through 100, 200, 300, and 400 ppm introduced ozone, respectively, compared to no ozone addition, while the corresponding exergy efficiency increments were found to be 0.09%, 0.78%, 2.82%, and 5.36%, respectively. The in-cylinder combustion improvement in the applied fuels with the ozone addition triggered the higher thermal efficiency of the engine, while denoting the higher rate of exhaust and cooling losses in all cases. The resultant experimental outcome also unveiled a significant load extension of RCCI engine operation using ozone-based additive. Furthermore, it was observed that the ozone usage holds promise for the emissions reduction of CO and HC although at the expense of the increased NOx emissions.