Mini–map Sensor, Y 16 Xe
The previously used Map sensor (intake pipe pressure sensor) has been replaced by a Mini–Map sensor (1). The Mini–Map sensor is installed directly on the intake manifold (2). Due to the omission of the hose connection, possible sources of faults have been reduced.
The Mini–Map sensor measures the changes in pressure in the intake system which affect the engine load and engine speed. The sensor signal is processed by an amplifying circuit, which is integrated in the pressure sensor, and supplies the output voltage. The voltage signal is directly proportional to the difference in pressure between the reference vacuum which is found in the Mini–Map sensor, and the intake pipe pressure.
The measurement principal is the following:
If certain crystals are subjected to pressure or a difference in pressure, the charge carrier is briefly modified. An electrical voltage pulse is generated. This effect is known as the Piezo effect. Quartz and tourmaline crystals are used for this type of application.