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Closed Loop Lambda Control🔗

This module is responsible for calculating fuel trims, which are then passed on to the Injection Time module for use in calculating flow rate.

To do this, the module performs the following tasks:

  1. Determines whether to activate closed loop lambda control for cylinder bank 1 and cylinder bank 2. This is based on a number of factors, including:
    • The lambda sensor for each cylinder bank's exhaust (Lambda Sensor 1/2 Input Status) must be ON.
    • The Closed Loop Lambda Control Enable table value for the current throttle position and engine speed must be 1 (enable).
    • Engine run time must be greater than Closed Loop Lambda Enable Delay.
    • Engine coolant temperature must be greater than Closed Loop Lambda Control Engine Coolant Temperature Threshold.
    • After Start Enrichment Disengaged must be TRUE.
  2. Once closed loop lambda control has been enabled for a cylinder bank, the lambda error for the bank is calculated for that bank (Lambda Setpoint - measured lambda value).
  3. A transport delay compensation control loop is used to calculate the delay compensation for each cylinder bank:
    1. The calculated lambda error and the length of time specified in Lambda Transport Delay are used to determine the amount of error due to transport delay (Lambda Transport Delay Error).
    2. The Lambda Transport Delay Error is used to calculate the Lambda Transport Delay Proportional Term and Lambda Transport Delay Integral Term.
    3. The Lambda Transport Delay Weighting Factor Term is calculated by multiplying the Transport Delay Weighting Factor by the change in lambda correction over the period specified in Lambda Transport Delay.
  4. A closed loop lambda controller determines the short term fuel trim that will be applied to each cylinder in the bank (Lambda 1 Correction / Lambda 2 Correction):
    1. The lambda error is used to calculate the closed loop proportional and integral terms for the cylinder bank.
    2. A raw correction amount is determined using the closed loop proportional and integral terms as well as the output of the transport delay compensation controller.
    3. The final correction is produced by comparing the raw correction to the Lambda Closed Loop Maximum and Lambda Closed Loop Minimum.