Test Groups 1BMXT04.4E53, 1BMXV04.4LEV & 1BMXV05.4LEV
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2001 BMW Z8, 2001 BMW X5, 2001 BMW M5, 2001 BMW 750iL, and 2001 BMW 740iL. 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.
- 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 3 different ranges: fault additive per time unit, multiplicative fault and fault additive per injection.
- Ranges Of Learning Correction Coefficients - Lambda deviations in range No. 1 are compensated by an additive correction value multiplied by an engine speed term. By this, an additive correction per time unit is created. Lambda deviations in range No. 2 are compensated by a multiplication factor. Lambda deviations in range No. 3 are compensated by an additive correction per injection cycle. A combination of all 3 ranges will be correctly separated and compensated. Each value is adapted in its corresponding range only. But 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. See Fig 1.
- 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 .