C 350 (204.056) V6-3.5L (272.961) (2008)
/v6-3.5l_(272.961)/Page-1203002.png)
The temperature of the heating resistor (RH) is detected by the sensor resistor (RS). For temperature changes due to an increased or reduced rate of air
flow, the electronics readjust the voltage at the heating resistor (RH), until the temperature difference is reached again 160 °C.
The ME-SFI [ME] control unit uses this control voltage as a measurement of the air mass supplied.
The air mass is transmitted via a frequency signal (low frequency for low air mass) to the ME-SFI [ME] control unit. Using DAS, the cycle duration of
the frequency signal can be read out in "micro seconds".
The intake air temperature is detected by the integral intake air temperature sensor (B2/5b1) in the hot film mass air flow sensor.
Hot film mass air flow sensors with the number A 273 094 08 48 and higher transmit an additional signal to the ME-SFI [ME] control unit. With this
so-called ratio-metric frequency signal, the ME-SFI [ME] control unit compensates for temperature and voltage influences on the air mass signal.
The ME-SFI [ME] control unit also detects the version of the hot film MAF sensor via the duty cycle.
