Engine smoothness control is balancing the speed variation for each individual cylinder caused by variable injection amount and each cylinder´s efficiency. This is obtained by an application that sends an exact fuel amount for each cylinder at each injection time.
The marginal values depende on the injection amount and is between +/-4,9 and +/-5,9mg/stroke.
The function is active within specific marginal values:
Engine speed: idle up to 3300 rpm.
Injection amount: 2,5 to 45 mg/stroke.
Monitoring:
If the compensation for some cylinder is outside the specified marginal values, 2 fault codes can appear:
4B10 Smoothness control correction quantity too high.
4B11 Smoothness control correction quantity too low.
Observe:
The maximum compensation depends on injection amount and is between +/-3 and +/-10mg/stroke.
The indicated amount should be between the following limits for all the cylinders:
Min: -5,0 mg/stroke.
Max: 4,0 mg/stroke.
Evaluation of result:
OK, -5,0 to 4,0 mg/stroke.
Critical, amount <-5,0 or >4,0.
An unacceptable deviation of the correction injection amount can have the following causes.
Defect injector nozzle.
Low compression.
Defect exhaust recycling.
Test prerequisites:
Engine idle running.
Procedure:
Start the engine.
Start the function "Smooth running measurement".