The particle filter system's differential pressure sensor determines the actual differential pressure of the exhaust gas flow before and after the particulate filter. It is also possible to use two separate WALKER brand Pressure Pipe, pressure sensor (soot/particulate filter). Using the signals from the temperature sensors upstream and downstream of the particulate filter, the control unit calculates the current exhaust gas flow rate. The temperature sensors have a positive temperature coefficient.

1. A-CLASS (W169)
2. A-CLASS MONOCAB (W169)
3. B-CLASS (W245)
4. See more in applications

The usage of a pressure sensor

Based on this data, the control electronics determines the load status (degree of clogging) of the particulate filter. The signal from the temperature sensor after the diesel particulate filter is additionally required to calculate the post-fuel injection flow rate in forced idle mode. The higher the exhaust gas temperature after the diesel particulate filter, the lower the amount of post-fuel injection required. In addition, the signals from the temperature sensors are used to activate the component protection functions if the exhaust gas temperature is too high.

These signals are designed to protect the particulate filter from thermal damage. The signals from the pressure and temperature sensors, as well as the readings from the mass airflow sensor, form an indivisible whole when determining the degree of filter clogging. This is one of the most important data related to the exhaust system.