The burning of diesel fuel in the DOC of the particulate filtering system of diesel engine during the regeneration process

The burning of additive fuel in the DOC (diesel oxidation catalyst) of the after treatment system of diesel engine was investigated in this paper. The DPF (diesel particulate filter) is considered as the most effective device to reduce the particle emission of diesel engine. During the regeneration process of DPF, extra fuel has to be injected into exhaust pipe to raise the exhaust temperature such that the carbon particles deposited inside DPF can be burned out. If the diesel fuel burning rate is too low, there will be penalty in fuel economy as well as emission increment. The conversion efficiency and the reaction rate of diesel fuel inside DOC were studied with a Cummins engine and a set of DPF system. It was found that the conversion efficiency was low in most conditions that have been tested. Besides, a theoretical model was developed to find out the activation energy of burning reaction. It was found that the activation energy is 137.1 kJ/kmole.