Temperature sensor upstream of SCR catalytic converter, component description

B14.40-0069-06

Represented on vehicle 382.177

Arrangement

1 SCR catalytic converter

2 Temperature sensorbefore the SCR catalytic converter (17B03)

The temperature sensorbefore the SCR catalytic converter (2) is fastened to the outside of the inlet chamber of the SCR catalytic converter (1)

B14.40-0143-05

Represented in vehicle 384.223

1 SCR catalytic converter

2 Temperature sensorbefore the SCR catalytic converter (17B03)

Task

The temperature sensorbefore the SCR catalytic converter (2) records the temperature of the exhaust gas flow in the inlet chamber of the SCR catalytic converter (1) and transmits this information, as an electric tension signal, to the SCR chassis control module.

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

Composition

The temperature sensorbefore the SCR catalytic converter (2) consists of a threaded stainless steel housing and an electric connector.

The inside of the sensor contains a PTC resistance. PTC stands for "Positive Temperature Coefficient" and means that the electric resistance increases as the temperature increases.

The temperature sensorbefore the catalytic converter (2) is a passive sensor. i.e., it is not supplied with tension.

Function

The temperature of the exhaust gas flowing by the temperature sensorbefore the SCR catalytic converter (2) 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, based on the electric resistance value.