Important Nomenclature of IC Engine

Important Nomenclature of IC Engine

Cylinder Bore: The nominal diameter of the working cylinder is called cylinder bore and is designated by the letter ‘d’ and is usually expressed in millimeter (mm).

Piston Area: The area of diameter equal to the cylinder bore is called piston area and is designated by the letter ‘A’ and is usually expressed in square centimeter (cm²).

Stroke: The nominal distance through the working piston moves between two successive reversals of its direction of motion is called the stroke and it is designated by the letter ‘L’.

Dead Centre: the position of the working piston and the moving parts which are mechanically connected to it, at the moment when the direction of the piston motion is reversed at either end of the stroke is called the dead centre.

Top Dead Centre (TDC): It is the dead centre when the piston is farthest from the crankshaft. In this piston is at the top most position in the engine cylinder.

Bottom Dead Centre (BDC): It is the dead centre when the piston is nearest to the crankshaft. In this piston is at the bottom most position in the engine cylinder.

Swept Volume (V_s): The nominal volume swept by the working piston when travelling from one dead centre to the other is called Swept volume.

Clearance Volume (V_c): The nominal volume of the combustion chamber above the piston when it is at the top most dead centre is the clearance volume.

Compression Ratio(r): It is the ratio of the total cylinder volume when the piston is at the bottom dead centre.