Understanding Engine Lubrication Systems: Wet Sump Types

Engine lubrication is vital for reducing friction, wear, and heat within the engine. Different systems are used to supply oil to moving parts. One common type is the wet sump lubrication system.

In a wet sump lubrication system, the engine's oil is stored in a reservoir, typically located at the bottom of the engine block, known as the oil sump. The oil is then circulated from this sump to the various engine components requiring lubrication and drains back into the same sump by gravity.

Let's look at the options provided and determine which one is not a wet sump lubrication system type:

• Splash system: In this wet sump system, dippers attached to the connecting rods splash oil stored in the sump onto the crankshaft, cylinder walls, and bearings. The oil is drawn directly from the sump.
• Pressure feed system: This is a widely used wet sump system where an oil pump draws oil from the sump and forces it under pressure through oil passages drilled in the crankshaft, connecting rods, and cylinder block to lubricate bearings and other critical parts.
• Splash and pressure system: This system combines aspects of both splash and pressure lubrication. Some components may receive pressure lubrication from a pump drawing oil from the sump, while others are lubricated by splashing oil from the sump.
• Velocity feed system: The term "Velocity feed system" is not a standard or recognized classification for engine lubrication systems, particularly not in the context of distinguishing between wet sump and other fundamental types like dry sump or mist lubrication. The other options listed (Splash, Pressure feed, Splash and pressure) are established methods used within a wet sump system to circulate oil stored in the sump. Therefore, "Velocity feed system" is the one that does not fit the description of a wet sump lubrication system type.

Based on the typical classifications of engine lubrication systems, the splash system, pressure feed system, and combined splash and pressure system are all types of wet sump systems because they rely on the oil being stored in and circulated from the engine's sump. The "Velocity feed system" is not a recognized type of wet sump lubrication system.