the maintance of SCR aftertreatment system

Urea nozzle
The function of the urea nozzle is to inject the urea solution at a certain pressure provided by the urea pump into the tail gas of the exhaust pipe. The urea nozzle has one urea pipe connector and two cooling water connectors. The two cooling water connectors are the water inlet and return ports for the engine coolant to cool the urea nozzle to prevent the urea nozzle from failure due to high temperature.

Urea tank
The urea tank is mainly used to store urea solution, and there is a liquid level temperature sensor on the urea tank.

SCR box
The catalyst is another core unit of SCR tail gas post-treatment system, which has two functions: catalytic conversion of tail gas and noise elimination. SCR box assembly consists of box type and barrel type. The barrel type SCR box assembly has two appearances, one is side inlet and the other is rear end outlet (side inlet and outlet); One is front inlet and rear outlet (end inlet and end outlet). The SCR box assembly is fixed on a suitable position of the vehicle with a bracket and a tension strap. It is connected with the engine exhaust connecting pipe through the intake flange. The SCR box assembly is integrated with a urea nozzle, a temperature exhaust sensor and a nitrogen oxygen sensor. In order to prevent the urea nozzle and the nitrogen oxygen sensor from failing due to collision during transportation and handling, the urea nozzle and the nitrogen oxygen sensor are installed with protective frames. The SCR catalyst is equipped with a honeycomb carrier. Avoid entering large objects (such as plastic bags, rocks, etc.) during disassembly or assembly, otherwise the engine exhaust will be blocked.
Urea Solution
Urea aqueous solution (Diesel Emission Fluid), referred to as DEF. The vehicle urea uses the internationally standard 32.5% urea solution, which is composed of 32.5% high-purity urea and 67.5% deionized water.