Short Answer:

Splash lubrication is a simple method of supplying oil to engine parts by splashing. In this system, the lower end of the connecting rod or dipper hits the oil in the sump, causing it to splash on moving parts like crankshaft, piston, and bearings. This helps in reducing friction and cooling the engine components.

It is mostly used in small and medium-speed engines where the load is not very high. The system does not require an oil pump and works automatically with engine motion, making it inexpensive and easy to maintain.

Detailed Explanation :

Splash Lubrication

Splash lubrication is one of the oldest and simplest methods used in engines and machinery for lubricating moving parts. It works on the principle of splashing oil from the sump onto the different components of the engine. This system is mostly used in small internal combustion engines, compressors, and small gearboxes where the operating speed and load are moderate. The main purpose of this lubrication system is to reduce friction, wear, and heat between the moving parts to ensure smooth and efficient operation.

In splash lubrication, the oil is stored in a sump located at the bottom of the engine crankcase. The rotating parts of the engine, usually the crankshaft or a dipper attached to the connecting rod, dip into the oil and splash it around the interior of the crankcase. The splashed oil reaches the cylinder walls, bearings, pistons, and other moving parts, forming a lubricating film between them. After lubrication, the oil falls back into the sump and is reused continuously during engine operation.

Working of Splash Lubrication System

The working of the splash lubrication system is very simple. The engine crankcase has a sump that holds the lubricating oil. The lower end of each connecting rod has a small projection called a dipper or scoop. When the crankshaft rotates, the dipper dips into the oil in the sump and splashes it throughout the crankcase. The oil drops fall on the bearings, cylinder walls, and other moving parts that require lubrication.

As the engine speed increases, the splashing action becomes stronger, and more oil is distributed to the parts. The oil that collects on the moving parts forms a thin film that reduces metal-to-metal contact and friction. After completing its function, the oil returns to the sump due to gravity, where it is ready for the next cycle. This process continues automatically as long as the engine is running.

Main Parts of Splash Lubrication System

1. Oil Sump: It is the reservoir that stores the lubricating oil at the bottom of the engine.
2. Connecting Rod Dipper: A small spoon-shaped projection fixed to the connecting rod that dips into the oil and causes splashing.
3. Crankcase: The part of the engine that encloses the crankshaft and contains the splashed oil.
4. Oil Passages and Holes: Some parts have drilled holes to allow oil to flow to bearings and other critical areas.

Advantages of Splash Lubrication

• Simple Design: The system does not require a pump or any complex mechanism.
• Low Cost: It is inexpensive to install and maintain.
• Automatic Operation: It works automatically with engine motion without external control.
• Reliable for Small Engines: Ideal for small engines like lawnmowers, motorcycles, and small generators.
• Reuses Oil: The oil continuously circulates, reducing wastage.

Disadvantages of Splash Lubrication

• Limited Use: Not suitable for high-speed or high-load engines because oil distribution is not uniform at higher speeds.
• No Pressure Control: The oil is not supplied under pressure, so some parts may get insufficient lubrication.
• Poor Cooling: The oil may not reach all hot parts effectively, leading to overheating.
• Dirt Accumulation: Contaminants in the oil may remain in the sump and affect lubrication quality.

Applications of Splash Lubrication

Splash lubrication is commonly used in:

• Small four-stroke petrol engines.
• Motorcycles and scooters with small engines.
• Portable generators and lawnmowers.
• Air compressors and small pumps.
• Agricultural and small industrial engines.

It is mainly chosen for systems where continuous and high-pressure lubrication is not required.

Importance of Splash Lubrication

Splash lubrication is important because it provides a simple and cost-effective way to reduce friction in low to medium-speed engines. Even though it lacks pressure control, it offers reliable lubrication for smaller systems that do not need complex mechanisms. The system works automatically, requires less maintenance, and ensures that essential parts receive oil for smooth movement.

Conclusion:

Splash lubrication is a simple and efficient system suitable for small engines where operating speed and load are moderate. It works by splashing oil from the sump to various moving parts, reducing friction and wear. Although it is not suitable for heavy-duty or high-speed engines, its simplicity, low cost, and reliability make it one of the most commonly used lubrication methods in small mechanical systems. Proper maintenance of oil level and cleanliness ensures the long life and smooth working of machines using this system.