Good Dispersant/Detergent Qualities
WARNING: This page does not describe the selected car, but rather 180 other vehicles, including the 2014 BMW i8, 2014 BMW i3, 2014 BMW Z4, 2014 BMW X6 M, and 2014 BMW X6. However, it is still accessible from the selected car via links, so may be relevant.
To limit or slow down the formation of combustion deposits and acidic components, together with abrasive particles and dirt from the intake air, good engine oils contain a detergent additive. Deposits of carbon and dirt are loosened and suspended in the oil, being drained away at the next oil change.