Closed Loop Lambda Control - enable conditions
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 BMW Z4, 2008 BMW X5, 2008 BMW X3, 2008 BMW 528xi, and 2008 BMW 528i. However, it is still accessible from the selected car via links, so may be relevant.
Closed loop lambda control is enabled (with a delay) at the start of a driving cycle and can be temporary or permanently deactivated during the driving cycle. The turn-on delay at the start of a driving cycle is described by the following enable conditions:
- the upstream oxygen sensor operability is detected i.e. the upstream HO2'S operating temperature has been reached
- a calibrated delay time, after end of engine start, has elapsed
Closed loop lambda operation is disabled during the driving cycle, if the following operating condition, which permits only mixture enrichment by the lambda controller, is fulfilled:
- when catalyst overheating prevention is active
Only for linear Lambda Sensor disable conditions:
- the A/F ratio set-point value lies below oxygen sensor's measurable limit
Closed loop lambda operation is further deactivated during a driving cycle when any of the following conditions are fulfilled:
- during fuel cut-off or cylinder shut-off and immediately afterwards till a calibrated integrated mass air flow threshold is exceeded
- the mass air flow is below a calibrated threshold that leads to the minimum possible injection time