2003 3BMXV04.4LEV
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.
- Mixture Pilot Control - Air mass taken in by engine and engine speed are measured. These signals are used to calculate an injection signal. This mixture pilot control follows fast load and speed changes.
- Lambda Controller - PCM compares oxygen sensor signal of sensor upstream of the catalyst with a reference value and calculates a correction factor for pilot control.
- Active 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. See Fig 1. With this 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, then MIL is illuminated and fault is stored. See Fig 2-Fig 3 .