Different Types of Oil Pump

Oil pump is generally located inside the crankcase below the oil level. The function of the oil pump is to supply oil under pressure to the various engine parts to be lubricated. Different types of oil pump used are as follows:

Gear Type Pump. It consists of two meshed spur gears enclosed in a housing. There is very little clearance between the gear teeth and housing. One gear is attached to a shaft, which is driven through suitable gears from the camshaft or crankshaft of the engine. The other gear is free to revolve on its own bearing. When the pump is in action, the oil is drawn between the gear teeth from the inlet side, carried around between the gears and pump housing, and forced out from the outlet side. The pressure and quantity of the oil supplied by the pump depends upon the speed of the gears. This type of pump is almost universally used in the automotive engine, due to its simplicity in construction. It can deliver oil at a pressure of about 2-4 kg/cm2. A pressure relief valve is provided in oil pump to relieve the excessive pressure due to high engine speed or clogged oil lines.

Gear Type Pump

Double Rotor Type Pump. It consists of an inner and outer rotor within the pump body in place of gears, that is, two lobes mesh internally. The external rotor has one more lobe than on the internal rotor. The oil is displaced from the inlet to the outlet side in the same way as in gear type pump. The inner 4 lobe rotor drives the outer 5 lobe rotor at a reduce speed and causes a depression as the rotor lobes separate. This occurs opposite the inlet, thus oil enters the space between the inner and outer rotors, and as the lobes come together again, the oil between them is forced up between the two rotors and out of the outlet.

Rotor Pump

Plunger Type Pump. It consists of sliding plunger or piston, which is driven by camshaft eccentric and reciprocates (up and down) in the pump body acting as cylinders. A non return valve is fitted in the oil submerged bottom of the body. While moving up, the plunger sucks oil from the inlet through the valve. While moving down, it forces out the oil through outlet, as the inlet valve is closed and delivery valve is opened. This type of pump is used to a very limited extent, mainly on stationary engines.

Plunger Pump

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