What Is Wet and Dry Oil Sump System? Functions, Diagram, Types, How They Work, Advantages, And Disadvantages
The wet sump, located at the bottom of the engine block, acts as a reservoir for engine oil, ensuring its circulation. The dry sump, situated around the engine, maintains the oil’s presence at the bottom.
The wet sump is a standard oil sump in an automobile engine, serving as a reservoir and lubricating system. It contains oil in a single pump, allowing for a fast oil circulating process.
The sump is made of thin-shaped stainless steel and collects oil at rest. Wet sumps are mounted at the crankcase’s bottom, serving as oil storage.
A wet sump serves important purposes in a car engine, including covering the engine completely to prevent dirt entry, cooling hot oil, and preventing dirt from entering the engine. Oil sumps help keep dirt from entering the engine, while the oil filter keeps small dirt.
The sump also serves as a gauge for oil, allowing for easy oil draining for new installation. Overall, the wet sump is crucial for maintaining a clean and efficient engine. The wet sump lubricating system offers common advantages such as economical operation, faster oil circulation, and reduced maintenance.
It also features components like baffles, windage tray, and dipstick for oil controls. However, it has limitations such as limited oil circulation, easy oil starting, and a single oil pump. Despite these disadvantages, the wet sump is widely used in commercial cars due to its cost-effectiveness and ease of maintenance.
Dry sump lubrication is a process used to manage oil in two-stroke and four-stroke internal combustion engines. It involves pumping oil at different stages, with a minimum of two stages. The first stage is for pressure supply, which supplies oil from the bottom of the reservoir.
An adjustable pressure regulator supplies oil under pressure through the filter into the engine. The next stage is scavenging the oil out of the dry-sump pan and returning it and gases to the external reservoir. A cooler is used between the inline of scavenge outlets and the external reservoir.
Dry sump systems are commonly used on larger diesel engines, racing cars, aerobatic aircraft, and high-performance motorcycles due to their reliability, oil capacity, and less oil starvation.
A dry sump system offers numerous advantages over a wet sump, such as improved engine reliability, reduced oil starvation, increased horsepower, large intake oil capacity, improved stability and handling, and easier maintenance.
However, dry sump systems also have disadvantages, such as adding weight, complexity, and cost to the engine, requiring extra pumps and lines, taking up large space, and requiring additional oil and maintenance.
Additionally, they can cause inadequate upper valvetrain lubrication if too much oil vapor is removed from the area. Despite these drawbacks, dry sump systems are still a viable option for high-performance engines, as they help control gasses trapped in the oil and improve pump efficiency.
A wet and dry oil sump system works by circulating engine oil to cool bearings and other moving parts. In a wet-sump system, oil is drained through gravity into the sump, while in a dry sump, oil is moved to an external reservoir before being directed to engine components.
Oil cooling rate differs between the two systems, as the oil in the reservoir must return before recirculating. A pressure pump cools and de-aerates engine oil before recirculating it, preventing oil shortages.
Modern motorcycles use wet sump lubrication for inline four-cylinder engines, as they require space under the frame. Dry lubrication is suitable for motorcycles with more intense energy, such as the Honda CB750.
Wet sump lubrication stores oil in the oil pan, while dry lubrication has an external reservoir for oil storage.
Wet sumps are used on small engines with small power consumption, while dry lubrication is suitable for high-performance vehicles.
Oil circulation in wet sumps is limited to engine moving parts, while dry lubrication stages oil treatment before recirculating. Commercial vehicles often use wet sumps, while racing cars use dry lubrication.
FAQs
What is wet sump and dry sump?
A wet sump system stores oil in a pan, while a dry sump system stores oil in a separate tank, leaving the pan dry. An externally mounted pump scavenges oil from the pan, delivers it to the storage tank, and returns it.
What is an oil sump system?
An oil sump system is not just for storing oil; it also helps reduce oil foaming by allowing oil to settle and efficiently cool it during engine operation, ensuring a smooth and efficient operation.
What is the difference between a wet sump and a dry sump on an aircraft?
The difference between a wet sump and a dry sump on an aircraft is the engine’s crankcase, which stores oil in a reservoir, and the engine’s crankcase, which pumps oil to an external tank, ensuring efficient oil circulation.
What is a dry sump used in?
Dry sump systems are crucial components in racing cars, providing numerous advantages during high revs and cornering speeds, especially when the vehicle is subjected to extreme use.
Related: Engine Lubrication System Explained!
