Actively regenerative exhaust aftertreatment system and method for active regeneration thereof

Abstract

The invention relates to an active regeneration method of a tail gas aftertreatment system. The method is used for carrying out aftertreatment on tail gas of a diesel engine and regenerating the functions of a diesel oxidation catalyst and a particulate oxidation catalyst which the tail gas passes through sequentially. The method comprises the steps of detecting the working conditions of the diesel engine; calculating the operating mileages of the diesel engine under the different working conditions; judging whether active regeneration is needed according to the working conditions and the accumulative operating mileage of the diesel engine; if yes, raising the exhaust gas temperature of the diesel engine to more than 270 DEG C. By means of the method, air pollution can be reduced.

Description

technical field [0001] The invention relates to the field of exhaust aftertreatment of high-pressure common rail diesel engines, in particular to an active regeneration exhaust aftertreatment system and an active regeneration method thereof. Background technique [0002] Diesel engines will produce a large amount of exhaust gas after combustion. This exhaust gas cannot be directly discharged into the air. It needs to be treated before being discharged into the air. For the treatment of exhaust gas, diesel oxidation catalyst (DieselOxidization Catalyst, DOC) is generally used. If the bare engine emits high particulate matter, a particulate oxidation catalyst (Particulate Oxidizaiton Catalyst, POC) will also be installed. For the DOC+POC system, if the diesel engine runs at low speed in urban conditions for a long time, the exhaust temperature in the engine exhaust pipe will be low, and sometimes it is difficult to reach the light-off temperature of DOC. At this time, the DO...

AI Technical Summary

Problems solved by technology

For the DOC+POC system, if the diesel engine runs at low speed for a long time in urban conditions, the temperature of the exhaust gas in the engine exhaust pipe will be low, and sometimes it is difficult to reach the light-off temperature of DOC

At this time, the DOC does not work, which will cause a large amount of soluble organic matter to adhere to the surface of the active material of the DOC, and the catalyst will lose its activity.

If fuel with high sulfur content is used, there will be sulfate and solidified sulfide attached to the catalyst surface of DOC, causing DOC poisoning and loss of activity

After the DOC loses its activity, no NO2 will be generated, and the carbon particles in the granular oxidizer behind it cannot react with the NO2 in the exhaust gas, so the carbon particles will accumulate in the POC, which will cause the POC to lose its function or be damaged.

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