Liquid heating type metering jet pump in SCR (selective catalytic reduction) system

Abstract

The invention discloses a liquid heating type metering jet pump in an SCR (selective catalytic reduction) system which is used for jetting a reducing agent in the SCR system into an exhaust pipe. The liquid heating type metering jet pump comprises a metering jet unit and a water heating unit for heating the metering jet unit, wherein the metering jet unit comprises a pump body, a diaphragm pump, a metering valve, a baseplate and a liquid flow channel; the diaphragm pump and the metering valve are arranged on the pump body; and the liquid flow channel comprises a liquid flow pipeline arranged on the pump body, a reflux pipeline, a liquid suction joint, a liquid outlet joint and a liquid return joint, and the water heating unit comprises a water circulating pipeline, a water inlet joint anda water outlet joint which are arranged on the pump body. The liquid heating type metering jet pump adopts a way of introducing heated cooling water of an engine into a metering pump for realizing circulating flow, and the pump body and the reducing agent in the pump body can be heated in the cold season, thereby improving the utilization rate of energy; and furthermore, the structure is compact and the degree of integration is high.

Description

technical field [0001] The invention relates to a reducing agent injection control device in a diesel vehicle tail gas treatment and purification system, in particular to a liquid heating metering injection pump in an SCR (Selective Catalyst Reaction, selective catalytic conversion route) system. Background technique [0002] As the society's requirements for environmental protection are getting higher and higher, the country's efforts to protect the environment are getting stronger and stronger. The relevant state departments have issued relevant policies on motor vehicle emissions, especially the implementation of the "National IV Standard". Emission control is becoming more stringent, and it is necessary to further reduce 30% to 50% of pollutants on the basis of meeting the "National III Standard" to meet the standard. According to the normal implementation process of the standard, the "National IV Standard" will be implemented nationwide in 2012. [0003] It is now known...

AI Technical Summary

Problems solved by technology

[0004] The most common reducing agent in the SCR system is 32.5% aqueous urea solution, which will freeze at -11°C, especially in the cold winter, the temperature in some places can be as low as -30°C, which makes the SCR system in The use in areas with lower temperatures is limited, so the freezing problem must be solved by heating the urea storage device and pipelines; Heating is carried out by electrifying and heating. This heating method increases the connection of wires, which is difficult to disassemble and maintain, and consumes a lot of energy, which also affects the life of the battery.

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