Terminology used in Ic Engine

The terminology used in IC Engine

Bore- 

The inner diameter of the cylinder is known as the bore.

Top dead center(TDC)- 

The maximum displacement of the piston from the mean position is known as Top dead center.

In this case, connecting rod and crankshaft are in the same line.

When the top dead center is achieved then pressure and temperature of charge increased and ready for combustion.

Bottom dead center(BDC)-

In the case of the vertical engine, the lowest point at which piston can travel is known as the bottom dead center.
In the case of the 4-stroke engine, BDC is achieving two times in a single complete cycle.

Stroke length- 

The distance between TDC and BDC is known and stroke length.

Stroke volume- 

The volume between TDC and BDC  is known as the stroke.

Pressure ratio- 

The ratio of  {stroke volume +clearance volume} to clearance volume is known as pressure ratio.

Efficiency- 

Efficiency is defined as the ratio of net work output to the heat supplied.