Air-assisted urea injection device capable of being emptied

Abstract

The invention relates to an air-assisted urea injection device capable of being emptied. The air-assisted urea injection device comprises a urea solution pipeline and an air pipeline, wherein the urea solution pipeline comprises a urea box, a liquid feeding pipeline, a urea pump and a liquid discharging pipeline which are connected in sequence; the urea box is filled with a urea solution; the air pipeline comprises a compressed air source, an air inlet pipeline, an air pressure regulation valve and an air outlet pipeline, which are connected in sequence. The air-assisted urea injection device further comprises a multi-way reversing device, a urea nozzle and a liquid returning branch pipe; the other end of the liquid discharging pipeline is communicated with one end of the multi-way reversing device; the other end of the multi-way reversing device is communicated with the urea nozzle; the other end of the air outlet pipeline is communicated with the multi-way reversing device; the liquid returning branch pipe is provided with a liquid returning solenoid valve; one end of the liquid returning branch pipe is communicated with the liquid discharging pipeline; the other end of the liquid returning branch pipe is connected with the urea box; and the multi-way reversing device is a multi-way valve comprising at least four ways.

Description

technical field [0001] The invention relates to a urea injection device for diesel engine tail gas treatment, in particular to an air-assisted urea injection device that can be emptied. Background technique [0002] The main pollutant in diesel engine exhaust is NOx. In order to make diesel vehicles meet the requirements of national emission regulations, the main technical route in my country is selective catalytic reduction (SCR). In the SCR post-treatment system, urea solution is used as a reducing agent to remove diesel engine exhaust. In order to meet the requirements of the country's corresponding emission regulations. The working principle of the urea injection device is: the exhaust gas enters the exhaust pipe, and a urea nozzle is installed on the exhaust pipe, which is sprayed into the urea solution for vehicles. The urea generates ammonia after hydrolysis and pyrolysis at high temperature, and passes through the interior of the catalytic converter. , Ammonia and ni...

AI Technical Summary

Problems solved by technology

When the urea solution for vehicles crystallizes, the exhaust pipe of the engine will be partially or even completely blocked, and it will also cause changes in the waste flow rate, a decrease in the conversion rate, and the exhaust gas will also be affected.

Urea cannot be fully used, resulting in waste, and the uniformity of urea spray distribution will also be affected, which eventually leads to blockage of the nozzle of the injection module. In the case of high-temperature exhaust, urea crystallization will decompose and produce ammonia gas, polluting surroundings

[0004] Therefore, this solution will cause the urea solution to crystallize in the exhaust pipe, which will affect the exhaust of the engine and even affect the performance of the engine.

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