Smooth running measurement


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:

  1. Engine speed: idle up to 3300 rpm.

  2. 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:

  1. 4B10 Smoothness control correction quantity too high.

  2. 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:

  1. Min: -5,0 mg/stroke.

  2. Max: 4,0 mg/stroke.

Evaluation of result:

  1. OK, -5,0 to 4,0 mg/stroke.

  2. Critical, amount <-5,0 or >4,0.

An unacceptable deviation of the correction injection amount can have the following causes.

  1. Defect injector nozzle.

  2. Low compression.

  3. Defect exhaust recycling.

Test prerequisites:

Procedure:

  1. Start the engine.

  2. Start the function "Smooth running measurement".