Ejection metering module for SCR (selective catalytic reduction) and controlling method of ejection metering module

Abstract

The invention discloses an ejection metering module for SCR (selective catalytic reduction) and a controlling method of the ejection metering module. The ejection metering module comprises a support, a pulse pump mounted at one end of the support, an upper end cover fixed at the other end of the support, an ejection nozzle and a controller, and is characterized in that the support extends from the upper portion of a DEF (diesel exhaust fluid) storage tank deeply to the bottom of the DEF storage tank and is fixed on the diesel exhaust fluid storage tank via the upper end cover, the controller controls the pulse pump to work, the pulse pump comprises a solenoid driver, a plunger pump and an internal flow passage which penetrates through the pulse pump axially, working fluid (DEF) enters an inlet of the internal flow passage via a first filter arranged at the inlet at the lower end of the internal flow passage, an outlet of the internal flow passage is higher than the inlet of the same in arrangement, part of the working fluid in the internal flow passage is pumped to the ejection nozzle through the plunger pump, and the other part of the working fluid is drained from the pulse pump via the outlet of the internal flow passage. Characteristic parameters of the pulse pump are prestored in the controller, so that the ejection metering module is capable of working in a slave mode or an intelligent (master) mode.

Description

technical field [0001] The invention belongs to the technical field of engine exhaust aftertreatment, and in particular relates to a NOx selective catalytic reduction (SCR) system and its control technology for engine exhaust aftertreatment. Background technique [0002] With the increasingly prominent environmental problems, energy saving and emission reduction has become a hot topic at present, and the country has successively issued a series of vehicle emission standards. In this regard, vehicles powered by internal combustion engines need to be installed with exhaust after-treatment systems to meet the increasingly more stringent emission requirements. For example, SCR (Selective Catalytic Reduction) technology, which is currently mainly used for catalytic treatment of NOx and other pollutants in diesel engine exhaust. [0003] SCR technology needs to quantitatively inject 32.5% urea aqueous solution (also called diesel exhaust treatment fluid DEF=Diesel Exhaust Fluid, ...

AI Technical Summary

Problems solved by technology

Due to the high surface tension of the DEF working fluid, when filling the DEF working fluid, the liquid often cannot pass through the filter smoothly into the SCR metering pump, resulting in the difficulty of initial liquid intake

In addition, the SCR metering pump will generate a large amount of steam when it is working. If it cannot be removed in time, it will affect its normal work and cooling.

[0008] In addition, existing technology is difficult to work in any climate without auxiliary heating at all

Since the existing device for providing the jet power source is too large or cannot be implanted into the DEF liquid storage tank due to other reasons, an auxiliary ice-melting device is required, which makes the system more complex and bulky, and the cost remains high

Therefore, solving the problem of complex system structure is a realistic and urgent problem.

[0009] To sum up, the existing technology uses quite complex auxiliary devices to solve the problems of ice melting, cooling and crystallization prevention of the SCR injection metering device, which leads to new problems such as high manufacturing and use costs and difficult production and maintenance.

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