Terminolgogy and Major Parts of an IC Engine

I.C ENGINE TERMINOLGOGY

The standard terms used in I.C Engines are

1. Bore:

Inside diameter of the cylinder is termed as Bore.

2. Top Dead Center (TDC):

The extreme position reached by the piston at the top of the cylinder in the vertical engine is called Top Dead center.

3. Bottom Dead Center (BDC):

The extreme position reached by the piston at the Bottom of the cylinder in the vertical engine is called Bottom Dead center.

4. Stroke: The nominal distance travelled by the piston in the cylinder between  the extreme upper and lower positions of the piston (TDC &BDC) is termed as  stroke.  

5. Compression ratio (r): 

  It is the ratio of Maximum cylinder volume to the Clearance volume.

6. Cylinder volume (v): 

  It is the sum of swept volume and the Clearance volume.

  V = Vs + Vc 

7. Swept volume (Vs): 

  It is the volume of space generated by the movement of piston 

from one dead center to another dead center.

8.Clearance Volume( Vc):

It is the space in the cylinder, when the piston is at Top Dead

Center

MAJOR PARTS OF AN IC ENGINE

1.  Cylinder

•         It is a round cylindrical casting in which a piston slides in and out to make strokes.

•         Combustion take place inside the cylinder. The cylinder is closed by a cylinder head.

Material: Grey cast iron, Aluminium

2. Cylinder head

It is fitted to the top of the cylinder. It has inlet and outlet values, spark plug, Fuel injector, Water jackets.

Material: C.I, Aluminium 3. Piston

It is a device which transmits the energy (or) force of the expanding gas to the connecting rod. It slides up and down inside the cylinder.

Material: C.I, Aluminium alloy, Cast steel

4. Piston rings

Piston rings are inserted in the grooves of piston. There are two

types of rings.

1) Oil ring ( One ring is used)

2) Compression ring( Two ring is used)

5. Connecting rod

It converts the reciprocating motion of the piston into rotary motion of

crankshaft. The small end of the connecting rod is connected to piston and the big end is connected to the crankshaft.

Material: Plain carbon steel, Aluminium alloys

6. Crank shaft

It is the device used for getting power from the motion of the piston and connecting rod and this power is applied to the flywheel.

Material: Alloys steel.

7. Camshaft

It operates the opening and closing of the engine values. It has number of cams which are driven by crank shaft through timing gears. The function of the cam is to convert the rotary motion into the linear reciprocating motion

Material: Alloys steel

8. Crank case

It is the bottom portion of the I.C engine and holds the cylinder and the crank case. It also serves as a pump for the lubricating oil.

Material: Aluminium alloy, Cast iron 9. Flywheel:

It is a big wheel attached with crankshaft. It maintains the speed of the

engine.

10. Valves: The function of the value is to admit the fresh charge in the cylinder and to send the

exhaust gases out. There are two values namely inlet value and outlet value.

Material: Inlet value: Nickel chrome.

Outlet value: Nickel chrome, Stainless steel etc

11. Water Jackets

Water jackets are provided in the cylinder head. The purpose of water jackets is to keep the walls of the engine cool.