Experimental study on combustion and emission of ternary-fuel combined supply SI engine with oxyhydrogen/butanol/gasoline at different excess air ratios

Both oxyhydrogen and butanol are renewable alternative fuels. Based on gasoline/butanol compound injection mode, although the introduction of oxyhydrogen can effectually enhance the optimal BDIr (butanol direct injection ratio), it also leads to an increase in NO emission. Therefore, this paper further studies the influence of lean-burn on the combustion and emission of ternary-fuel combined supply engine with oxyhydrogen/butanol/gasoline. In this paper, three variables are set, namely five BDIr (0–80%), five ONPIv (oxyhydrogen negative pressure inhalation volume) (0–16 L/min) and five λ (1.0–1.4). The results show that the larger the λ, the more significant the impact of oxyhydrogen on improving combustion and thermal transfer inside the cylinder. With the increase of ONPIv, CoVIMEP, CA 10–90 and CA 0-10 decrease, IMEP increases. Under all lean-burn conditions, ONPI can reduce CO and HC emissions. Under the condition of λ = 1.4, when ONPIv = 16 L/min, NO emission is 49.98% lower than the value of the original engine. Moreover, based on BDIr = 40%, 16 L/min ONPIv can elevate the λ limit from 1.41 to 1.83. In summary, “1.1 = λ ≤ 1.2+ONPIv = 16 L/min+60%≤BDIr≤80%” is the excellent control strategy of ONPI + BDI + GPI engine. The synergistic influence of lean-burn and larger BDIr can greatly reduce gasoline consumption and NOx emission caused by oxyhydrogen, but also worsen the mixture combustion atmosphere. ONPI can effectively improve this problem, and further increase energy efficiency. The coupling technology of ternary-fuel combined supply and lean-burn has a positive impact on improving thermal transfer efficiency, optimizing mixture combustion and decreasing gaseous emission.