Integral urea metering nozzle structure

Abstract

The invention relates to an integral type urea metering nozzle structure which comprises a valve rod, a protective sleeve and a swirl nozzle; the outer part of the lower end of the swirl nozzle is welded with the protective sleeve; a solution storage cavity is formed between the outer wall of the lower end of the swirl nozzle and the inner wall of the protective sleeve; a jet orifice is formed in the lower end part of the swirl nozzle; the valve rod is connected in an axial hole of the swirl nozzle in a sliding and inserting manner; a valve rod flow passage is formed in the valve rod in the axial direction from top to bottom; a communicating hole, corresponding to the solution storage cavity, is formed in the swirl nozzle; a lower connecting hole is formed in the valve rod; the inner end of the communicating hole is matched with the outer end of the lower connecting hole; an upper connecting hole is formed in the valve rod; an outer sealing surface is arranged at the lower end part of the valve rod; the lower end part of a nozzle middle hole lower section is connected with the upper end part of the jet orifice through an inner sealing surface; and a swirl hole which communicates the solution storage cavity and a solution swirl cavity is formed in the swirl nozzle. The integral type urea metering nozzle structure has the advantages of convenience in processing and manufacturing, easiness in controlling critical size and tolerance, good performance and the like.

Description

technical field [0001] The invention relates to a nozzle structure, in particular to an integral urea metering nozzle structure. Background technique [0002] In the prior art, there are many exhaust after-treatment systems for reducing exhaust pollutants of internal combustion engines. Among them, the SCR (Selective Catalytic Reduction) urea injection system, as one of the exhaust after-treatment devices for reducing nitrogen oxides in exhaust, has become a popular choice for medium- and heavy-duty vehicles. Mainstream technical solutions that meet China IV and above emission regulations. The principle is to reduce the nitrogen oxides in the exhaust gas to nitrogen and water by injecting urea solution into the exhaust gas of the diesel engine under the action of high temperature and catalyst. The urea solution is sprayed into the exhaust pipe through the metering unit. The metering unit directly affects the conversion efficiency of nitrogen oxides and is an important devic...

AI Technical Summary

Problems solved by technology

[0003] There are two forms of urea metering unit: pressure type and swirl atomization. Due to the low-pressure injection, the pressure type has the disadvantages of poor atomization quality, difficulty in ensuring atomization consistency, small spray aperture and easy blockage. The existing swirl mist Most of the transformation methods adopt the form of split pressing and welding, which makes it difficult to guarantee the sealing between the valve core and the seat surface, and requires high processing and welding positioning technology.

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