CL 550 4MATIC (216.386) V8-5.5L (273.961) (2009)
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Engine Control Module: Description and Operation
GF07.61-P-4022MIS ME-SFI Lambda Control, Function
GF07.61-P-4022MIS ME-SFI Lambda Control, Function
- as of model year 09
Component Identification
Function requirements for lambda regulation, general points
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Circuit 87M ON (engine control ON)
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Engine running
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Coolant temperature > -10 °C
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Operating temperature reached in LH and RH O2 sensors upstream of the catalytic converter (G3/3, G3/4)
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Engine idling or partial-load range
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Deceleration fuel shutoff not active.
Lambda regulation, general points
The mixture composition is controlled within the narrowest limits around lambda= 1 in order to achieve high conversion of the exhaust gases (exhaust
gas conversion) in the catalytic converters.
For this purpose, the ME-SFI [ME] control unit (N3/10) reads the following sensors:
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Hot film MAF sensor (B2/5), engine load
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Coolant temperature sensor ()B11/4
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LH and RH O2 sensors upstream of catalytic converter, oxygen sensor signals
Lambda regulation function sequence
The O2 sensors upstream of the catalytic converter react to the oxygen content in the exhaust and send the corresponding voltage signals to the ME-SFI
[ME] control unit. This then regulates the mixture composition by adjusting the injection time of the fuel injection valves (Y62) so that lambda=1 is
reached. 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 the
catalytic converter.
