Functional description

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The sensor system of the broadband oxygen sensor consists of ceramic layers of zirconium dioxide (laminate). The heating element inserted in the laminate rapidly ensures the required operating temperature of at least 760 °C. The broadband oxygen sensor has 2 cells, a so-called measurement cell and a reference cell. The two cells are coated with electrode made of platinum.

Fig 1: Identifying Broadband Oxygen Sensor And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

Graphic shows an oxygen sensor before catalytic converter

Index	Explanation
1	Broadband oxygen sensor
2	6-pin plug connection (5 used)
3	Housing for oxidation catalytic converter and diesel particle filter

The air ratio measured by the oxygen sensor and the air mass measured by the hot film air mass meter are used to determine a mean fuel injection rate across all cylinders. This value is compared with the fuel injection rate specified by the DDE control unit. If there is a deviation, the air mass is adapted to the actual fuel injection rate by adjusting the exhaust-gas recirculation (EGR) valve in such a way that the correct air ratio is set.