ME-SFI lambda control, function - GF07.61-P-4022AMG
ENGINE 156.980 in MODEL 164, 251
ENGINE 156.982 in MODEL 209
ENGINE 156.983 in MODEL 211, 219
ENGINE 156.984 in MODEL 216, 221
The mixture composition is controlled within the narrowest possible limits around λ= 1 in order to achieve a high conversion of exhaust gases (exhaust gas conversion) in 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 λ=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 λ 0.7 to 4.0) as O2 sensors upstream of TWC.
The function of the lambda control (closed-loop operation) is dependent upon:
- 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.
Exhaust gas conversion in the three way catalytic converter
Example:
Assuming a leaner fuel-air mixture is produced. This has the following consequence, that the O2 sensor voltage drops and the ME-SFI [ME] control unit compensates for this lean drift through a matching enrichment.
This makes it possible to achieve a fuel-air mixture of approximately λ=1.
The reading of the lambda control factor with the STAR DIAGNOSIS moves 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.
| Component description for fuel injection valves | Y62y1-Y62y8 | GF07.03-P-6010AMG | ||
| Component description for the coolant temperature sensor | B11/4 | GF07.04-P-6040AMG | ||
| Component description for O2 sensors | G3/3, G3/4 | O2 sensors upstream of TWC | GF07.04-P-6100AMG | |
| G3/5, G3/6 | O2 sensors downstream of TWC | GF07.04-P-6100AMH | ||
| Component description for the crankshaft Hall sensor | B70 | GF07.04-P-6220AMG | ||
| Component description for the hot film mass air flow sensor | B2/6, B2/7 | GF07.07-P-6000AMG | ||
| Component description for the ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000AMG | ||
| Component description for the accelerator pedal sensor | B37 | GF30.20-P-2010AMG | ||
| Component description for the three-way catalytic converter | 157, 158 | GF49.10-P-2010AMG | ||