Anti-blockage device for air way of measurement unit of SCR system

Abstract

An anti-blockage device for an air way of a measurement unit of an SCR system comprises a urea box, a liquid inlet pipeline of the urea box is connected to a diaphragm pump, a liquid return pipeline of the urea box is connected to a liquid return solenoid valve, the liquid return solenoid valve is connected to a pressure stabilizer, the pressure stabilizer is connected to a measurement unit air valve, the measurement unit air valve is connected to a premixer, one end of the premixer is connected to a nozzle, the other end of the premixer is connected to a solenoid drive check valve, the solenoid drive check valve is connected to an air pressure adjuster, the air pressure adjuster is connected to an air valve, the air valve is connected to an air inlet, the air valve and the air pressure adjuster are connected to a strong-blowing solenoid valve, the strong-blowing solenoid valve is connected to the nozzle, an anti-blockage device body is connected between the measurement unit air valve and the premixer and is connected to a check valve piston for the premixer, a spring is arranged at the upper part of the check valve piston, a static iron core is arranged at the lower part of the check valve piston, solenoid coils are arranged outside the static iron core, and a fast mixing base body is arranged around the premixer and the check valve piston.

Description

technical field [0001] The invention relates to an after-treatment system for automobile and diesel engine exhaust, and more specifically relates to an anti-blocking device for an air circuit of an SCR system metering unit. Background technique [0002] Now with the continuous upgrade of emission standards for diesel locomotives, only using in-cylinder purification technology can no longer meet the national emission standards IV and above. It is already difficult to modify the engine for diesel vehicles to meet the National IV emission requirements. Major automobile manufacturers around the world have turned their attention to the selective catalytic reduction technology (SCR, Selective Catalytic Reduction) with great development potential for post-treatment of flue gas denitrification to meet the requirements of the National IV emission standards. The selective catalytic reduction system needs to use the urea pump to extract the urea solution from the urea tank and inject i...

AI Technical Summary

Problems solved by technology

[0002] Now with the continuous upgrading of emission standards for diesel locomotives, only the use of in-cylinder purification technology can no longer meet the national emission standards IV and above

It is already difficult to modify the engine for diesel vehicles to meet the National IV emission standards. Major automobile manufacturers around the world have turned their attention to the selective catalytic reduction technology (SCR, Selective Catalytic Reduction) with great development potential for post-treatment of flue gas denitrification to meet the requirements of National IV emission standards. The selective catalytic reduction system needs to use the urea pump to extract the urea solution from the urea tank and spray it into the exhaust pipe with a certain accuracy. When the injection of the ordinary gas-assisted SCR metering unit is slightly blocked, the metering valve The power is small, and the liquid cannot be forced to discharge, causing the reducing agent to crystallize in the pump and block the pump

After the nozzle is clogged, it is not enough to use a mechanical one-way valve to close the air circuit in time, and urea can still enter the air circuit, which will cause the blockage of the air circuit and make the SCR metering unit unable to work normally.

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