不同海拔条件下柴油燃烧火焰温度和碳烟特性研究

To study the altitude effects on the diesel combustion process under cold-start condition, the thermodynamic state of the diesel engine cylinder was simulated in a constant volume combustion chamber under the plain condition and the 2000 m altitude condition. Flame temperature and KL factor distribution for soot concentration characterizing were obtained by the two-color method under different conditions. Results show that the simultaneous decrease of ambient temperature and pressure can produce a coupling effect, resulting in the diesel ignition delay from 2.0 ms to 3.13 ms increasing, when the altitude increases from 0 m to 2000 m. As the altitude increases, the average flame temperature decreases during the diesel combustion process, while the local high temperature area disappears and the total KL factor decreases. The relationship between soot characteristics and flame temperature is affected evidently with altitude increases. With the increase of altitude and the decrease of flame temperature, the soot oxidation rate decreases in the soot oxidation dominated process and the impact of local flame temperature on local soot concentration weakens.