Like working with engines and love everything that engines are all about? Then this is the article to read. Today we will be focusing on some basic definitions used in engine terminology. It will help you to get acquainted with the basics of an engine.

We all know that engines are of various types the two-stroke engine, the four-stroke engine and the six-stroke engine, All having their unique configuration and operational style. However there are some basic terminologies that constitute an engine, and today we will be focusing on them.

Also Read: 18 Mechanical Properties Of Material Which Every Mechanical Engineer Should Know

So here goes :

TDC- Top dead centre: This is the point where the engine piston will come to a halt or rest before moving again to complete an engine cycle. This happens in every reciprocating type engine. The piston comes to the top at a point from where it can no longer move. This point is called the top dead centre.

BDC: Bottom Dead Centre: Now if a piston has moved towards the top dead centre point then to complete the engine cycle it has to come down. The point at which a downward moving piston comes to a halt  during an engine cycle is called bottom dead centre.

Also Read: 18 Mechanical Properties Of Material Which Every Mechanical Engineer Should Know

Stroke: There is a limit to the movement of the piston. Hence stroke is defined as the maximum distance that a piston can travel from top dead centre to the bottom dead centre.

Bore: Bore is defined as the inner diameter of a cylinder.

Total Volume of the cylinder: The volume of an engine’s cylinder when its piston is at the bottom dead centre is defined as the total volume of the cylinder. It is generally denoted in CC.

Clearance Volume of Cylinder: It is the opposite of total volume of the cylinder and is measured when the piston is at top dead centre. It is also known as minimum volume of the cylinder.

Displacement volume: Also known as swept volume, it is calculated as swept volume = total volume – clearance volume.

Compression Ratio: It is the representation ratio between the value of the maximum and minimum capacity of the engine. Generally speaking, a high compression ratio is always desirable as it derives the maximum efficiency for a given size of an engine. Also, an engine with high compression ratio is also thermally more efficient.

Ignition Delay: It is the delay in time from the point the ignition is turned on to crank the engine to the actual start of the engine or combustion of fuel in the cylinder.

Also Read: 18 Mechanical Properties Of Material Which Every Mechanical Engineer Should Know

Mean Effective pressure: Ratio of total volume of the engine to the work done by the engine is known as mean effective pressure. It is an essential reading for judging the efficiency of the engine. This value is independent of the engine displacement hence gives a great insight.

So here are some of the widely used engine terminologies for your knowledge.