Urea solution double-nozzle aftertreatment device and control method thereof

Abstract

The invention belongs to the technical field of diesel engine tail gas SCR urea solution injection, and particularly relates to a urea solution double-nozzle aftertreatment device and a control method thereof. The urea solution double-nozzle aftertreatment device comprises a first urea nozzle and a second urea nozzle, wherein the first urea nozzle is arranged behind an engine vortex; the rear end of the first urea nozzle is sequentially connected with a first SCR carrier, a DOC carrier, a DPF carrier, a second SCR carrier and an ASC carrier; the second urea nozzle is arranged between the DPF carrier and the second SCR carrier; and the second urea nozzle is connected with the first urea nozzle and is connected with a urea pump. The double nozzles are adopted, the price of the nozzles is low, the total volume of the SCR carriers is hardly changed, the total cost is controlled, the first urea nozzle fully utilizes the characteristic that the temperature of the position behind the vortex is high, a urea solution is hydrolyzed to generate ammonia gas, the ammonia gas participates in the reaction of the first SCR carrier, the device is limited by the arrangement space, the size of the first SCR carrier is small, and the efficiency is high at the low temperature.

Description

technical field [0001] The invention belongs to the technical field of diesel engine tail gas SCR urea solution injection, and in particular relates to a urea solution double-nozzle post-processing device and a control method thereof. Background technique [0002] National VI regulations GB17691-2018 for heavy-duty diesel vehicles have been promulgated and implemented. The mainstream technical solutions for SCR post-treatment catalysts in the National VI phase are: DOC+DPF+urea nozzle+SCR+ASC, all of which can solve the exhaust emission problem at that time. At present, diesel vehicles have passed the SCR technology route, and the concentration of nitrogen and oxygen in the exhaust gas after treatment is already very low, and the conversion rate is close to 99%. However, this is measured in the laboratory based on the WHTC working conditions of regulations. Vehicle Exhaust Gas Test In the PEMS experiment, the whole vehicle has a lot of backward dragging and cooling, and the ...

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Problems solved by technology

These methods will cause a serious increase in fuel consumption. In essence, it is to increase a part of fuel that does not work and only generates heat. It is difficult to meet the requirements of fuel consumption restrictions and regulations. At the same time, it will increase HC pollutants and the heating effect is limited.

In-cylinder post-injection also causes severe oil dilution

Throttle action will cause supercharger surge and output torque fluctuation

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