Important Terms in IC Engine Technology

Clearance Volume
The Clearance Volume is the empty space remaining in the cylinder when the piston is at the Top Dead Centre (TDC).  It is denoted by Vc

Bore
The internal diameter of the engine cylinder is known as the bore.  The cylinder is made using a boring process, hence then name.

Top Dead Centre
The upper most point in the cylinder which the piston reaches is called the Top Dead Centre or TDC.  Once this position is reached, the piston reverses its direction and moves downwards.

Bottom Dead Centre
The bottom most point in the cylinder which the piston reaches is called the Bottom Dead Centre or BDC.  The piston reverses direction and moves upwards once this point is reached.

Stroke Length

The distance travelled by the piston in one stroke is called the stroke length.  It is the distance between the Top Dead Centre and the Bottom Dead Centre.  It is represented by L.

Swept Volume

The volume of the total space covered by the piston when moving between the Bottom Dead Centre and the Top Dead Centre is called the Swept Volume.