SL 600 (230.476) V12-5.5L Turbo (275.951) (2004)
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Oxygen Sensor: Description and Operation
GF07.61-P-4022M ME-SFI Lambda Control, Function
GF07.61-P-4022M ME-SFI Lambda Control, Function
- up to model year 08
Component Identification
The mixture composition is controlled within the narrowest possible limits around lambda= 1 in order to achieve a high conversion of the exhaust gases
(exhaust gas conversion) in the catalytic converters.
The O2 sensors upstream of TWC react to the oxygen share in the exhaust and transmits a corresponding voltage signal to the ME-SFI [ME] control
unit. Consequently, the mixture composition is modified by control of the injection quantity, so that lambda=1 is obtained. This process is repeated
constantly (control loop).
The ME-SFI [ME] control unit alters the mixture composition with a time delay in order to prevent any risk of jerking.
Control of the air/fuel ratio is much faster by using a wideband oxygen sensor (continuous signal of lambda 0.7 to 4.0) as O2 sensors upstream of TWC.
The function of the lambda control (closed-loop operation) is dependent upon:
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Coolant temperature at start (dependent on the particular operating condition)
^
Operating temperature of the O2 sensors upstream of TWC
^
Engine idling or partial-load range
^
Deceleration fuel shutoff not active.
Component Identification
