2003 3BMXV06.0N73
WARNING: This page is about a different car, the 2003 BMW 760Li, 2003 BMW 745i, and 2003 BMW 745Li. However, it is still accessible from the selected car via links, so may be relevant.
- Fuel System Monitoring General Description
- Mixture Pilot Control - Air mass taken in by engine and engine speed are measured. These signals are used to calculate an injection signal. Mixture pilot control follows fast load and speed changes.
- Lambda Controller - PCM compares oxygen sensor signal of sensor upstream of catalyst with a reference value and calculates a correction factor for pilot control.
- Adaptive Pilot Control - Drifts and faults in sensors and actuators of fuel delivery system as well as undetected air leakage influence pilot control. This causes increasing deviations of air/fuel ratio. Adaptive pilot control effects controller correction in 2 different ranges. See Fig 1. Lambda deviations in range No. 1 are compensated by an additive correction value multiplied by an engine speed term. An additive correction per time unit is created. Lambda deviations in range No. 2 are compensated by a multiplication factor. A combination of both ranges will be correctly separated and compensated. Each value is adapted in its corresponding range only. Each adaptive value corrects pilot control within whole load/speed range. At next start, stored adaptive values are included in calculation of pilot control just before closed loop control becomes active.
- Diagnosis Of Fuel Delivery System - Faults in fuel delivery system can occur which cannot be compensated for by adaptive pilot control. In this case, adaptive values leave a predetermined range. If adaptive value is outside a plausible range, MIL is illuminated and fault is stored. See Figure-Figure .