Highspeed endoscope system was designed to visualize the water injection process in the intake port of gasoline engine. The water injection processes were compared under two water injector layouts, different injection timings and injection pressures and the effects of these factors on fuel consumption and NOx emission were further analyzed by combining bench test data. The results showed that using 3∶10 watergasoline mass ratio at the point of 3 000 r/min and 1.4 MPa could lead to 3% decrease of fuel consumption and 20% reduction of NOx emission. The effects of water injection would hardly change for different injectors and layouts. The water injection timing affected the evaporation and cooling process after the water spray entered the cylinder. Under different injection timings, the differences of specific fuel consumption between them were little and NOx emission showed an opposite trend with it. In addition, injection pressure affected water spray atomization and movement. Higher injection pressure could produce a better effect of atomization, but lead to an earlier evaporation of water droplets in intake port that was not helpful to the incylinder cooling. It was finally found that the optimal fuel consumption could be achieved at the injection pressure of 0.8 MPa where NOx emissions gradually reduced as the injection pressure increased.
GUO Tao,LI Xiangchao,ZHANG Hong,YIN Qi,YANG Lei,LIN Changlin.
Visualization Study on Water Injection of Gasoline Engine Based on Endoscope[J]. Vehicle Engine. 2020, 0(3): 71-75 https://doi.org/10.3969/j.issn.1001-2222.2020.03.011
