Dispersant additive

A dispersant, or detergent-dispersant additive, is a lube-oil additive that keeps soot, oxidation products, and insoluble combustion residues suspended as fine particles instead of agglomerating into sludge and deposits. The polar additive molecules surround each carbon particle and hold it in colloidal suspension so the centrifuge and filters can remove it, protecting ring grooves and bearings from lacquer and varnish. In trunk-piston engine system oils the dispersant works with the detergent and the base reserve, where the base number neutralizes acids while the dispersant controls particulate fouling.