Components of The Combustion Engine

Have you ever wondered about how the different parts of an automobile engine make a car run??

Here is where you can find out!

What happens first?

You turn the ignition key- a switch is turned on so that electricity from a battery starts a starter motor, which will be used to turn a flywheel- which, in turn, revolves the “crankshaft”- an integral part of the internal combustion engine.  With the engine now started, the starter motor can be disengaged.
 
 

The Internal Combustion Engine

~ refer to the model right below as you go along….


 

1) So now the crankshaft is turning.  It is connected to a connecting rod (N) which pivots back and forth so that the       rotational motion of the crankshaft (P) can be translated to the linear motion of a piston (M)- a cylindrical piece of metal.  The piston moves up and down in a cylinder.  The piston moves down first.

2) With the piston down, the Intake valve (A) opens allowing the fuel and gas in. The valves are usually a metal shaft with a disk at one end fitted to block the opening of the cylinder.  The other end of the valves are connected to a camshaft.

3) The piston moves up- compressing the gas- with the combustion chamber (the area at the top of the piston and below the head) at its minimum

4) A spark plug (K) - an insulated conductor set in the wall or top of each cylinder- ignites the gas.  The inner end of the spark plug consists of 2 wires with a gap in which a high voltage current goes through to create the spark.

This current comes from a transformer/ ignition coil- which has a primary and secondary coil in close proximity to one another.  The current goes through the primary coil and is interrupted- this pulsation of the current creates a high voltage in the secondary and a rotary switch leads this current to the spark plug.
5) An explosion occurs as the ignited gas expands and moves the piston back down again.

6) The piston moves back up and the exhaust valve (J) is opened to let the “waste” gas/fuel out.

~The linear movement of the piston in this cycle is translated into the rotational motion of the crankshaft.~

Now the engine is ready for the next cycle, so it intakes another charge of air and gas…
 
Note : There are really usually about 4-6 cylinders like these in an automobile, and the area which houses these cylinders along w/ the piston and the crankshaft is called the engine block.
 
Other important components:
 Engine block- Can be “In line” or “V line.”  In Line means that the cylinder will stand upright over the crankshaft.  V line means that there will be 2 rows of cylinder set at an angle to each other and forming a “V.”

The Combustion Chamber- as stated- is at the top of the piston and below the head (D) .  This is the area where compression and combustion take place.  The size of the combustion chamber changes and has some max and min value.  The difference between the two is called the displacement and is measured in liters or Cubic centimeters.

The camshaft (I) :  A round rod with odd shaped lobes located inside the engine block or cylinder head.

~Connected to crankshaft by gear wheel, belt, or chain.  The revolution of the crankshaft forces the camshaft to turn which will cause valves to open and close at the right times.

Fuel Injection System- supplys the fuel that will flow into the intake port (C).

Cooling System (E) - At the sides of the cylinder- water is circulated through by means of a water pump and cooled by passing through the finned coils of a radiator.This cools the cylinder.

Sump (H) - the sump surrounds the crankshaft.  It contains some amount of oil, which collects in the bottom of the sump or the oil pan.

Piston rings:  Provide a sliding seal between the other edge of the piston and the inner edge of the cylinder.

~prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion

~keep oil in the sump from leaking into the combustion area where it would be burned and lost.

Works Cited:
1) http://www.howstuffworks.com/engine.htm
2)  http://encarta.msn.com/find/Concise.asp?ti=0085E000