Investigation of oxyhydrogen production from aqueous potassium hydroxide electrolysis to enhance the combustion efficiency of bio-isopropanol/gasoline engine

To explore the synergistic application of advanced combustion technologies and renewable fuels, aiming to achieve more efficient engine performance, lower emissions, and reduced fuel consumption, this study investigates the optimizing effect of the synergistic action between oxyhydrogen negative pressure inhalation (ONPI) and lean-burn on the combustion of a bio-isopropanol/gasoline dual-fuel combined injection engine. The experiments were conducted under the conditions of a speed of 1500 r/min, a manifold absolute pressure (MAP) of 42 kPa, and a bio-isopropanol direct injection ratio (BIDIr) of 40 %, with the experimental variables being different excess air ratios (λ = 1∼1.4) and oxyhydrogen negative pressure inhalation volumes (ONPIv = 0–16 L/min). The results show that ONPI significantly improves engine power performance; under λ = 1.4, the IMEP at ONPIv = 16 L/min is 6.37 % higher than that at 0 L/min. It also reduces emissions (under λ = 1.4, the HC emissions at ONPIv = 16 L/min are 33.81 % lower than those at 0 L/min) and cyclic variation (the CoVIMEP under optimal conditions is reduced by 29.76 % compared with the original engine), and the effect intensifies with the increase of λ. CO emissions are greatly affected by lean-burn; under λ = 1.1, CO emissions are reduced by an average of 90.4 % compared with those under λ = 1. Lean-burn can effectively suppress NO emissions. In addition, oxyhydrogen and lean-burn can synergistically improve indicated thermal efficiency, which reaches the highest value at λ = 1.4 and ONPIv = 12 L/min, being 2.82 % higher than that of the original engine.