GF07.61-P-4022G ME-SFI Lambda Control, Function
GF07.61-P-4022G ME-SFI Lambda Control, Function
ENGINE 273 in MODEL 463.202 /222 /236 /237 up to 31.5.12
- as of model year 2009
/YoM 08
B2/5 Hot film mass air flow sensor
B11/4 Coolant temperature sensor
G3/3 Left O2 sensor upstream of catalytic converter
G3/4 Right O2 sensor, upstream catalytic converter
N3/10 ME-SFI [ME] control unit
Y62y1 Cylinder 1 injector
Y62y2 Cylinder 2 injector
Y62y3 Cylinder 3 injector
Y62y4 Cylinder 4 injector
Y62y5 Cylinder 5 injector
Y62y6 Cylinder 6 injector
Y62y7 Cylinder 7 injector
Y62y8 Cylinder 8 injector
Exhaust gas conversion in the three way catalytic converter
A Exhaust gas emission
B Controlled range around Lambda=1 (catalyst window)
CO Carbon monoxide
HC Hydrocarbon
NOx Nitrogen oxides
Lambda Fuel air/fuel ratio
Function requirements for lambda control for the ME-SFI gasoline injection and ignition system (engine electronic) (ME), general points
^ Circuit 87M ON (engine control ON)
^ Engine running
^ Coolant temperature greater than -10°C
^ Operating temperature reached in LH and RH O2 sensors upstream of the catalytic converter
^ Engine idling or partial-load range
^ Deceleration fuel shutoff not active.
ME-SFI 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.
To do this, the ME-SFI [ME] control unit reads the following sensors:
- Hot film MAF sensor, engine load
- Coolant temperature sensor
- LH and RH O2 sensors upstream of catalytic converter, oxygen sensor signals
ME 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 wide band oxygen sensor (continuous signal of Lambda 0.7 to 4.0) as O 2 sensors upstream of the catalytic converter.
Example:
Assuming a leaner fuel-air mixture is produced. As a result, the oxygen sensor voltage drops and the MESFI [ME] control unit compensates for the leaner mixture by enriching it accordingly (extending the injection time).
This makes it possible to achieve a fuel-air mixture of approximately Lambda = 1.
The lambda control factor indicated with the Diagnosis Assistance System (DAS) changes towards +25 %.
The more the lambda control factor moves in the direction +25%, the leaner is the fuel air mixture and the greater is the enrichment of the mixture on the part of the ME-SFI [ME] control unit.
