Two-stroke Engines
Small two-stroke engines, as for motorcycles and lawnmowers, use crankcase compression: the mixture passes through the sump space in the crankcase. This precludes the use of both wet sump and dry sump systems, as excess oil here would contaminate the mixture, leading to excess oil being burned in the engine and so extremely high HC emissions. These engines are instead lubricated by petroil mixtures, where a carefully measured proportion of oil is added to the fuel tank (between 1:16 and 1:50 ratios). This oil is consumed immediately and entirely, so there is no need for a sump to collect and re-use it.
Four-stroke engines, as for almost all cars, and large two-stroke engines used in locomotives and ships can both use either wet or dry sumps. Large two-stroke engines do not use crankcase compression; instead they use a separate blower or supercharger, either a mechanical blower such as a Roots blower or else a turbocharger.
==Types of Wet Sump== 1) The Splash System 2) The Splash and Pressure System 3) The Pressure Feed System
Read more about this topic: Wet Sump
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