There are various types of lubrication system for lubricating the automobile engines.
- Petroil System
- Splash System
- Wet Sump (Pressure) System
- Semi pressure system
- Dry sump (Pressure) system
Petroil Lubrication System
This system of lubrication is generally adopted in two stroke petrol engines, like scooters and motorcycles. The lubricating oil is mixed into the petrol itself while filling in the petrol tank of the vehicle, in a specified ratio. The amount of oil to be added is about 1 part of oil to 10 part of gasoline by volume.
Splash Lubrication System
In this system of lubrication the lubricating oil is stored in an oil trough or sump. A scoop or dipper is made in the lowest part of connecting rod. When the engine runs, the dipper dips in the oil once in every revolution of the crankshaft and causes the oil to splash on the cylinder walls. This action effects the lubrication of the engine cylinder walls, piston pin, piston rings, crankshaft bearings, and big end bearings.
Wet sump Lubrication System
In this system of lubrication the engine parts are lubricated under pressure feed. The oil is stored in the crankcase or sump and is maintained at a certain level. The oil pump is usually submerged and driven by the camshaft. Oil pump takes the oil through a strainer and delivers it through a filter to the main oil gallery at a pressure of 2-4 kg /cm2. The oil from the main oil gallery goes to the main bearing and through the holes in the crankshaft webs, to the crankpins, from here it passes through holes to lubricate the big-end bearings. The camshaft may be either pressure or splash lubricated. Timing gear also may be pressure or splash lubricated. The valve tappets are lubricated by connecting the main oil gallery to the tappet guide surfaces through drilled holes. To prevent excessive pressure building up in the system, an oil pressure relief valve is incorporated, which permits excess oil to by-pass the system. Oil pressure gauge at the instrument panel indicates the oil pressure in the system.
Semi Pressure Lubrication System
In this type of system the oil pressure between 0.4 to 1kg/cm2 . This system some parts are lubricated by splash system and some parts are by pressure system. The parts such as cylinder wall, piston, piston pin, connecting rod extra are lubricated by splash system and remaining parts are by pressure system.
Dry Sump Lubrication System
The system in which the lubricating oil is not kept in the oil sump is known as dry sump system. In this system, the oil is carried in a separate tank, which aids cooling. Oil from the tank is fed to the engine by a pressure pump. The oil from sump is sent back to the oil tank by a separate delivery pump, known as scavenge pump. Scavenging pump usually has a capacity of one third greater than that of pressure pump. An oil cooler is incorporated between the sump and oil tank line to cool the oil. The main advantage of this system is that, there is no chance of break down the oil supply during up and down movement of the vehicle. The size of the sump can be smaller than that required for an engine operating on wet sump system.