Cylinder balancing
The objective of this function is to balance the combustion pulses from each cylinder. This is performed at idling speed to compensate for variations in the quantity injected into each cylinder and the differences in the efficiency of each cylinder. Compensation under other operating conditions is performed mainly for the differences in efficiency of each cylinder. This is achieved by calculating and changing the injected quantity for each cylinder individually.
The engine control module measures the speed of the crankshaft after each power stroke. When the cylinder is about to ignite the next time, a calculation is ready to compensate the quantity for the next combustion. This compensation quantity is adapted so that the next combustion results in the same working pulse after combustion as that in the other cylinders.
The average compensation quantity for the four cylinders is adjusted towards 0% so that the idling speed is not affected by the cylinder balancing function. The limit for the range of adjustment is 3 mg/combustion.
Cylinder balancing is not in operation
Calculations are performed with the following variables
