Why is it so important to use detergents and dispersants in diesel engine oil?

Quite simply detergents and dispersants in diesel engine oil are vital in controlling the combustion by-products which find their way into the crankcase.

Diesel fuel combustion (or incomplete combustion) is accompanied by the production of soot (unburned carbon). Prior to exhaust emissions legislation this soot simply passed into the atmosphere through the exhaust system.

Soot reduction has been accomplished by improving injector spray patterns,