Views:3 Author:Site Editor Publish Time: 2019-07-08 Origin:Site
Nowadays, many truck friends often hear problems such as blockage of SCR urea pipes, blockage of SCR urea quick connectors, etc., in fact, these problems are all from SCR, and do some things for truck owners from several aspects. Introduction:
First, what is SCR?
The principle of Selective Catalytic Reduction (SCR) is that under the action of the catalyst, the reducing agent NH3 selectively reduces NO and NO2 to N2 at 290-400 °C, and almost no oxidation reaction of NH3 and O2 occurs. , thereby increasing the selectivity of N2 and reducing the consumption of NH3.
The SCR system consists of an ammonia supply system, an ammonia/air injection system, a catalytic reaction system, and a control system. To avoid energy consumption by reheating the flue gas, the SCR reactor is generally placed after the economizer and before the air preheater. That is, the high dust section is arranged. SCR urea for vehicles. Ammonia is added to the horizontal pipe in front of the air preheater and mixed with the flue gas.
Selective Catalytic Reduction (SCR) technology has been used in Europe since 2003. As a relatively mature technology, it has become the mainstream of today's diesel exhaust gas treatment technology.
Second, what are the common problems with SCR systems?
During the operation of the SCR vehicle, due to the special nature of the SCR urea solution, the SCR urea line and the SCR urea quick connector will produce SCR urea crystals; when the crystallization is severe, the SCR urea line or the SCR urea quick connector will be blocked, resulting in excessive discharge, OBD. The light is on and the engine power is limited.
Third, the cleaning of the SCR urea quick connector
1. Remove the SCR urea quick connector;
Note: When disassembling the quick connector, the SCR urea pipe must be removed first, then the cooling water pipe, and finally the solenoid valve connector;
2. Put the SCR urea quick connector in the hot water and shake it from side to side;
The purpose of this is to dissolve the urea crystals quickly, and if necessary, it can be cleaned on the vehicle without removing the SCR urea line and the SCR urea quick connector cooling line. The cleaning method is the same.
Note: When cleaning, do not splash into the connector plug;
The quick connector is mounted using 3 M6 bolts. The bolt length is a minimum of 25mm and a maximum of 30mm.
Note: After each removal of the SCR urea quick coupling: the SCR urea quick coupling gasket should be replaced during assembly; after installing the SCR urea quick coupling, first install the solenoid valve connector, then install the cooling water pipe, and finally install the SCR urea pipe.
Fourth, the cleaning of the SCR urea pipe line
1. Remove the SCR urea line and fill the SCR urea line with hot water.
Note: When disassembling the SCR urea pipe, press the buckle on both sides of the SCR urea pipe connector and pull out the SCR urea pipe connector;
2. Shake the SCR urea tube from side to side to make the crystal in the SCR urea tube dissolve quickly;
3. Pour out the hot water in the SCR urea tube.
Note: When cleaning the SCR urea pipe, be careful not to splash water into the SCR urea pipe heating connector.