Muffler with reduction catalytic converter, component description

B14.40-0068-06

Represented on vehicle 382.177

Arrangement

The SCR catalyst (8) is attached to the right of the chassis frame.

Task

The SCR catalyst (8) reduces nitrogen oxides (NOx) generated by combustion of fuels into non-toxic nitrogen (N2) and water (H2O).

B14.40-0141-04

Represented on vehicle 384.223

8 SCR catalyst

B14.40-0038-06

Composition

2 Inlet tube - engine exhaust gas flow (inlet)

4 Reducing catalyst

5 Exhaust tube - exhaust gas (outlet)

6 Inlet chamber

7 Outlet chamber

8 SCR catalyst

9 Ceramic hive

10 Temperature sensorbefore SCR catalyst (17B04)

11 Temperature sensorafter SCR catalyst (17B03)

SCR catalyst (8) consists of a stainless steel housing. The reducing catalyst is inside. Located in the central portion, the ceramic hive (9) is coated with a layer of titanium dioxide (TiO2), tungsten oxide (WO3) and vanadium pentoxide (V2O5).

SCR catalyst (8) comprises a temperature sensorbefore the catalyst (10) for measuring the temperature in the inlet chamber (6) and a temperature sensorafter the catalyst (11) for measuring the temperature in the outlet chamber (7).

B14.40-0172-04

Function

1 AdBlue

2 Inlet tube - engine exhaust gas flow (inlet)

3 Hydrolysis route

4 Reducing catalyst

5 Exhaust tube - exhaust gas (outlet)

AdBlue (1) is injected into the heat flow of exhaust gases (2). In the hydrolysis route (2), it is converted into ammonia (NH3) in the first stage of the process. Ammonia (NH3) flows in the direction of the reducing catalyst (4), together with the nitrogen oxide molecules (NOx).

The ceramic hive (9) is the second stage of the reduction process: the nitrogen molecules along with the ammonia molecules (NH3) release energy in the form of heat. The only products resulting from the chemical reaction are nitrogen (N2) and water vapor (H2O), both of them not harmful to the environment.

For this procedure known as selective catalytic reduction, a particular operating temperature of the reducing catalyst is needed (4).

The temperature for that is 250°C. The temperature sensor in the inlet chamber of the muffler with reduction catalyst conveys through the SCR chassis control module, at preset intervals, the temperature to the engine control module (MR).