15 Important Car Engine Parts, You Must Know [Functions Explained | Pictures]

Cylinder Block

The cylinders of a multi-cylinder engine are cast as a whole and it is called cylinder block. The cylinder block is the main supporting structure of an engine.

Cylinder block is mounted with cylinder head at top and crankcase at the bottom. Both cylinder head and crankcase are attached to the cylinder block with the help of nuts and bolts.

Cylinder head consists of systems for air, fuel injection and spark plug (in case of SI engines). Crankcase gives housing to crank and acts as a sump for lubricating oil.

At every joint for e.g. in between cylinder block and cylinder head a gasket is placed. A gasket provides a leak free joint and allows heat conduction between different parts.

Cooling jackets are provided in cylinder head, cylinder block and crankcase assembly.

The inner surface of cylinder block, which is machined to a cylindrical shape is called bore or face.

Cylinder

As the name suggests the cylinder is cylindrical in shape. This the actual place where fuel burning happens and piston reciprocates. A cylinder is machined with a very high surface finish. It is case hardened, to obtain a very hard scratch free surface.

Piston

A piston is a cylindrical component, which fits inside the cylinder and forms a movable boundary. Piston moves smoothly inside cylinder, with the help of proper lubrication. A piston makes almost airtight contact with the cylinder walls, with the help of piston rings. Piston is the first link in transmitting the gas force into crankshaft.

Combustion chamber

A combustion chamber is an enclosure formed by cylinder walls, cylinder head and piston head. It is a place where the actual combustion of fuel takes place.

Intake manifold

Intake manifold is the pipe that brings air or air-fuel mixture into the combustion chamber for combustion. It is connected to intake valves.

In a diesel engine intake manifold is used for providing air to the engine, but in petrol engine intake manifold is used to supply fuel air mixture to the engine or combustion chamber.

From the construction of above manifold one can easily understand that is a manifold of four cylinder engine, because it has four outlets.

Exhaust manifold

Exhaust manifold is a pipe with takes out exhaust gases from the combustion chamber after combustion. It is connected to exhaust valves. Its construction is same as the inlet manifold.

Exhaust manifold has same function in both petrol and diesel engines, in both the cases it carries exhaust gas.

Intake and Exhaust valves

Inlet and exhaust valves are used to control and regulate charge (or air) coming to engine for burning and exhaust gases going out from the cylinder respectively.

They are provided either on cylinder head or on cylinder walls. They are commonly have mushroom shaped head.

In case of Petrol engines air and fuel mixture enters through inlet valve, but in diesel engines only air enters through intake valve. Exhaust valve in both the cases is meant for letting exhaust gases out.

Intake valves are connected to the intake manifold and exhaust valves are connected to exhaust manifold. Both intake and exhaust manifolds are discussed above.

Spark plug

A spark plug is a device which is used in spark ignition (SI) engines. Mainly Engines which use petrol as a fuel are spark ignition engines.

A spark plug creates a spark which is used to initiate combustion in SI engines. Spark plug derives its power either from a battery or magneto.

No doubt spark plug is one of the most important car engine parts used in gasoline (or SI engines).

Connecting Rod

A connecting rod transfers reciprocating motion from piston head to crank shaft, where it gets converted into rotary motion. Connecting rod has two ends small end and big end. Small end is connected to piston head with the help of gudgeon pin and big end is connected with crankshaft with the help of crank-pin.

Crankshaft

Crankshaft is one of the most important car engine parts. It converts reciprocating motion of the piston to rotary motion with the help of connecting rod. Connecting rod is the same rod which is discussed above and it transfers power from the piston to the crankshaft. Crankshaft has provisions for static and dynamic load balancing.

Piston rings

Piston rings are fitted in piston to provide leak free contact between piston and cylinder wall. However, they permit a small amount of lubricant pass through to provide lubrication for smooth functioning of piston. They are designed to bear high temperature and thrust.

There are mainly three kinds of piston rings are used in engines.

The first one is temperature ring. This piston ring is designed to bear extreme temperature.

The second one is pressure ring. This piston ring is designed to bear extreme pressure due to thrust generated by engine.

The third one is Lubrication ring. This piston ring is designed in such a way that a small amount of lubricant always passes through it to the combustion chamber.

Gudgeon pin

Gudgeon pin is a special kind of pin which connects small end of connecting rod to the piston. It understand it properly please refer above figure.

Camshaft

The camshaft controls the operation and timing of inlet and exhaust valves (discussed earlier in the article) with the help of a mechanism consisting of timing gears. It also provides drive to ignition system.

Cams

These are integral part of camshafts. Due to cams a camshaft is known as camshaft. Cams are mounted on the camshaft to control inlet and exhaust valve timings

Now its time to move to our last but most important car engine part.

Flywheel

The torque provided by the engine is not uniform and is fluctuating in nature. If a vehicle continues to move with this fluctuating power that it will cause huge discomfort to the rider and also it will decrease life of its different parts.

Hence to deal with the problem of fluctuating load a flywheel is used. A flywheel is generally mounted on camshaft.  It stores torque when its value is high and release it when its value is low in a cycle of operation. It acts as a torque buffer.

Also read: Explaining automotive tyres

Image sources: [Date: 10-12-2018]

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