Two-valve injection method of carbamide reducing agent

Abstract

The invention relates to a two-valve injection method of a carbamide reducing agent, which is characterized in that a pipeline on a carbamide reducing agent box is connected with a filter in series, liquid flows across the filter through the pipeline due to the driving effect of pressure, the pipeline of the filter is connected with two electromagnetic flow control valves in parallel, the two electromagnetic flow control valves can independently or simultaneously start the connection with a pressure maintaining valve, the pressure maintaining valve is communicated with a carbamide reducing agent nozzle, and the carbamide reducing agent can be injected into an exhaust pipe with the aid of air. By using the conventional industrial electromagnetic flow control valves, the invention solves the problem on the dose of the original carbamide reducing agent based on different control logic, thereby having high reliability and practical value.

Description

Technical field: [0001] The invention relates to a two-valve injection method of a urea reducing agent, which is applied to the post-treatment industry of automobile exhaust. Background technique: [0002] In the next few years, global automobile manufacturers, especially the United States and Europe, will enforce some stricter standards on vehicle nitrogen oxides NOx and particulate PM emissions, such as Euro 5 and Euro 6 emission standards. [0003] Under the pressure of emission regulations, on the one hand, foreign heavy-duty diesel engines for vehicles are constantly upgrading and improving their technology; , DPF (Diesel Particulate Filter) particle trap, DOC (Diesel Oxidation Catalyst) oxidation catalyst, etc. [0004] The essence of SCR technology is to use urea to decompose NH at high temperature 3 , NH as reducing agent 3 and NO in engine exhaust x The reaction is carried out under the combined action of catalyst and temperature, and under ideal conditions, n...

AI Technical Summary

Problems solved by technology

If you choose a domestically produced electromagnetic flow control valve with low precision to achieve control, the theoretically set flow rate is 5~85g / min. When a working condition requires a supply of 60g / min reducing agent, according to its error, its The actual flow range may reach 42~78g / min. For the flow rate of 42g / min, the possible result is that the supply of urea reducing agent is insufficient to remove the specified amount of NOx; while for the flow rate of 78g / min The possible result is that the supply of urea reducing agent exceeds the standard. Although the specified amount of NOx can be removed, it will definitely cause excessive escape of NH3. create new pollution

Images