Temperature sensor upstream of SCR catalytic converter, component description

B14.40-0001-06

Arrangement

3 SCR catalytic converter

5 Temperature sensorbefore the SCR catalytic converter (17B03)

The temperature sensorbefore the SCR catalytic converter (5) is fastened to the outside of the inlet chamber of the SCR catalytic converter (3)

Task

The temperature sensorbefore the SCR catalytic converter (5) records the exhaust gas flow temperature in the inlet chamber of the SCR catalytic converter (3) and transmits this information as an electric tension signal, to the SCR chassis control module.

Utilizing this resistance value, the MR control unit calculates the associated temperature.

Composition

The temperature sensorbefore the SCR catalytic converter (5) consists of a threaded stainless steel housing with an electric connector.

The inside of the temperature sensorbefore the SCR catalytic converter (5) contains a PTC resistance. PTC stands for "Positive Temperature Coefficient" and means that the electric resistance increases as the temperature increases.

The temperature sensor (5) is a passive sensor. i.e., it is not supplied with tension.

Function

The exhaust gas temperature flowing by the temperature sensorbefore the SCR catalytic converter (5) influences the measuring element inside the sensor and, therefore, the amount of electric resistance. The values of the electric resistance are transmitted, in predefined intervals, as an analog signal to the SCR chassis control module, where they are digitalized and sent to the engine control module (MR). The engine control module (MR) calculates the correspondent temperature, utilizing the electric resistance value as a base.