Influence and strategy optimization of fuel injection timing on PN and fuel consumption

Abstract

During the development of a CN Ⅵ light vehicle equipped with a GDI gasoline engine, the phenomenon of high PN appeared. In response to the operating conditions of the engine running in the WLTC cycle, a corresponding SOI sweep was performed on the dyno bench. The PN emissions of the engine has reduced by optimizing of SOI. The results show that when the SOI is sufficiently advanced, the oil film formed by the collision of the spray and the piston causes the PN emissions to increase significantly. In order to avoid the deterioration of the PN emissions, the SOI should be appropriately postponed. In the low load conditions, it is more appropriate to calibrate the SOI at 295°CA and 290°CA. In the medium speed area, it is more suitable to set it at 300°CA or later. The SOI in the higher speed area can be slightly advanced if necessary. And the impact of SOI on fuel consumption is more obvious at low speeds, but it is not obvious at the conditions of medium to high loads and speeds.

Analysis and experimental research on the influence of VVT point selection on exhaust temperature in low speed operating conditions

“…Under the same engine operating conditions, the exhaust temperature is directly affected by the ignition angle. [2][3][4][5] Under high load conditions, the closer the ignition angle is to the MBT ignition angle, the higher the combustion efficiency of the engine and the lower the exhaust temperature. At the same time, VVT affects the air intake of the engine, thereby affecting the engine's anti-knock ability.…”