Like all clouds, it forms when the air reaches its dew point, which is the temperature to which an air mass must be cooled for the water vapor in it to condense into liquid droplets.

In order to build the DPF pressure drop model based on air intake flow, DPF bed temperature, soot and fuel charge, the paper has carried out a series of tests, collected a mass of data.

Under the condition of constant phosphorus mass flow rate, the smog exit temperature would increase slowly while other parameters would decrease with increasing excess air coefficient.