Orthogonalization Analysis of the Effect of Pre-Combustion Chamber Hydrogen Injection Strategy on the Combustion and Emissions of a Gasoline Engine with Active Precombustion Chamber Under Lean-Burn Condition

Abstract

In the face of increasing environmental problems, reducing gasoline consumption and improving engine thermal efficiency have become a top priority. In this paper, stable combustion under ultra lean-burn (λ=2.1) conditions was achieved by using hydrogen as the fuel in the active pre-combustion chamber in a gasoline/hydrogen dual-fuel engine with an active pre-combustion chamber. The impact of pre-combustion chamber hydrogen injection strategy on the engine lean-burn characteristics is investigated. The actual experimental variables are four different hydrogen injection timings (HIT), hydrogen injection pressures (HIP) and ignition timings (IT). Meanwhile, in order to simplify the experiment and find the injection strategy that has the greatest effect on each combustion parameter of the engine, the orthogonalization method is chosen. The results show that HIT has the greatest impact on engine combustion and emission, followed by IT. The impact of HIP on combustion and emission is not very significant. Appropriate HIP with late HIT can significantly benefit engine combustion for better power and emission, but will cause the NOx emissions to increase. Therefore, “HIP of 3MPa, HIT of 160°CA BTDC and IT of 15°CA BTDC” is the best injection control strategy.

Keywords: active pre-combustion chamber, combustion and emission, orthogonalization analysis, gasoline, Hydrogen