Multiplicative adaptation: Notes
If closed loop continuously corrects a deviation in the fuel system, it will be adapted. Adaptation occurs every five minutes and takes 30 seconds.
The fuel quantity is always multiplied by a multiplicative adaptation factor that is 1.00 when the control module is new or has been de-energized. The multiplicative adaptation takes place during partial load. Purging is interrupted during adaptation as no other sources affecting the fuel may be present.
The entire closed loop deviation from 1.00 is moved to the multiplicative adaptation factor. This causes the right amount of fuel to be injected even though the closed loop is not active e.g. cold starts or when driving with a full load. After starting the engine a multiplicative adaptation must always occur before a additive. The limit values for the multiplicative adaptation are 0.75 and 1.25 respectively.
The following conditions must be fulfilled before multiplicative adaptation can take place:
- Closed loop active.
- No purging in progress; this takes place for 4 minutes and 30 seconds during each 5-minute period. However, a multiplicative adaptation will take place directly the first time the other conditions have been fulfilled.
- Engine coolant temperature exceeds 78°C.
- Engine speed 1200-2750 RPM.
- Engine load 130-310 mg/c.