Venturi reversing device and urea reversed pumping device based on device

Abstract

The invention discloses a Venturi reversing device and a urea reversed pumping device based on the device. The Venturi reversing device comprises a Venturi pipe and a two-way valve, the Venturi pipe communicates with the two-way valve through one pipe in series, and the position of a throat of the Venturi pipe communicates with another pipe; and the urea reversed pumping device comprises a urea box, a Venturi pipe, a liquid outlet pipe, a jetting pipe, a first valve and a first liquid return pipe, the end of a gradually-shrinking section and the end of a gradually-expanding section of the Venturi pipe communicate with the urea box through the liquid outlet pipe and the first liquid return pipe, the first valve is arranged on the first liquid return pipe, one end of the jetting pipe communicates with the throat of the Venturi pipe, and the other end of the jetting pipe communicates with an urea nozzle. According to the Venturi reversing device and the urea reversed pumping device, the Venturi effect is used, when a urea injection system stops working, residual urea solutions in the jetting pipe and the urea nozzle can be reversely pumped into the urea box, the urea pump assembly structure is more compact, reliable and durable, and the manufacturing cost is lower.

Description

technical field [0001] The invention relates to the field of diesel exhaust gas purification, more specifically, the invention relates to a Venturi reversing device and a urea back-pumping device based on the device. Background technique [0002] At present, diesel engine exhaust purification and nitrogen oxide reduction systems need to add a small amount of urea solution to the engine exhaust pipe. Urea decomposes into ammonia at high temperature, and with the help of SCR catalyst, it reacts with nitrogen oxides to generate nitrogen and water. Usually, the urea solution for diesel vehicles is an aqueous urea solution with a concentration of 32.5% (ie, the eutectic point of urea and water). [0003] The above-mentioned urea solution is stored in a container, that is, the urea tank and used on the vehicle, and is delivered to the urea nozzle by a booster pump to be released in the engine exhaust pipe. When the engine stops and the urea injection stops, the urea solution in t...

AI Technical Summary

Problems solved by technology

This kind of reversing device involves complicated mechanical actions, which is not only bulky, but also has poor sealing performance, which often leads to liquid leakage and seriously affects the reliability and service life of the urea pump assembly.

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