4 Stroke Engine cycle

1
4 Stroke Engine cycle
Part 1

• http//www.youtube.com/watch?v4HPV73v7Ub8

2
4 Stroke Engine cycle
3
Engine displacement

• A cylinders displacement is the volume of the
  cylinder when the piston is at BDC.
• It is the sum of the displacement of each
  cylinder.
• It is defined as the volume of air/fuel mixture
  an engine can draw in.

4
Engine displacement
Ex 700 cc (cubic centimetres) 1000 cc 1
Litre
5
Engine displacement

• Example Vehicle has 4 cylinders
• Each cylinder has a volume of
  700cc
• 700cc X 4 2800cc
• 2800cc 2.8 Litre

6
Torque

• Torque is the term used to describe a rotating
  force.
• More torque generally means a car can accelerate
  faster
• Torque is the actual reading of how hard and
  with how much Force the engine turns.

7
Horsepower

• Horsepower 1 hp 33,000 lb-ft / min
• One horsepower is the ability to lift 33000
  pounds one foot in one minute
• The horsepower specification for an engine tells
  you how much power the engine can produce. 
• Horsepower is the rate at which the engine does
  work

8
Horsepower calculations

• Formula
• HORSEPOWER (TORQUE RPM) / 5252
• A engine that makes 300 pound-feet of torque at
  4,000 RPM produces
• (300 x 4,000) / 5,252 228 horsepower at 4,000
  RPM

9
Torque and Horsepower

• Think about
• Torque being how hard you can pound away on
  bicycle pedals
• Horsepower being how fast you can spin the
  bicycle pedals.

10
Recap

• What is engine displacement?
• What is horsepower?
• What is Torque?
• What are the different parts of an engine?

11
The 4 stroke cycle

• http//www.youtube.com/watch?v60QX5RY_ohQfeature
  related
• Part 2

12
The four-stroke engine
13
Piston, connecting rod, crankshaft

• Is a can-shaped part closely fitted inside the
  cylinder.
• Piston rings consist of compression rings and oil
  rings.
• Crankshaft takes the up-down motion of the piston
  and convertors it to a rotation motion
• Connecting rod connects the piston to the
  crankshaft.

14
What is the 4 Stroke cycle?

• The 4 Stroke engine cycle consist of these
• 1) Intake
  180degree
• 2) Compression 180
  degree
• 3) Power/ Combustion 180
  degree
• 4) Exhaust
  180 degree
• Total engine revolution 720 degree
• One complete engine cycle consists of 4 engine
  strokes.

15
Intake

• The Intake Stroke consist of the piston
  travelling down.
• Intake valves are open to allow Air/Fuel mixture
  to come into the combustion chamber.

16
Intake system

• Intake plastic ducts
• Intake manifolds

17
Intake system
18
Intake system

• Fuel injectors are electronically controlled
  valves that spray fuel to mix with air.
• Creating that air fuel mixture

19
Spark plugs

• It is an electrical device that fits into
  the cylinder head and ignites air fuel mixtures.

20
The four-stroke engine
Inlet valve open
Exhaust valve closed
INTAKE STROKE
21
The four-stroke engine
Inlet valve open
Exhaust valve closed
INTAKE STROKE
Piston down
22
The four-stroke engine
Fuel in
Inlet valve open
Exhaust valve closed
INTAKE STROKE
Piston down
23
The four-stroke engine
Fuel in
Exhaust valve closed
Inlet valve open
INTAKE STROKE
Piston down
24
Recap

• What is the purpose of the intake system?
• What is the purpose of the spark plug?
• What is the purpose of the fuel injector?
• What is happening during the intake stroke?

25
4 Stroke engine

• Part 3
• http//www.youtube.com/watch?vq4Bk2TJJ6TM

26
Compression

• Compression stroke consist of the piston
  travelling back up.
• Both intake and exhaust valves are closed
• Air fuel mixture is now being compressed

27
The four-stroke engine
Exhaust valve closed
Inlet valve closed
COMPRESSION STROKE
28
The four-stroke engine
Inlet valve closed
Exhaust valve closed
COMPRESSION STROKE
29
The four-stroke engine
Inlet valve closed
Exhaust valve closed
COMPRESSION STROKE
30
Combustion/Power

• The piston is now at the TDC
• Spark plug ignites, creating a spark that ignites
  the compressed air fuel mixture.
• Explosion is created and the piston is forced
  back down.
• Hence the Power stroke
• Both valves are still closed

31
The four-stroke engine
Inlet valve closed
Exhaust valve closed
BANG
POWER STROKE
32
The four-stroke engine
Inlet valve closed
Exhaust valve closed
Piston down powerfully
POWER STROKE
33
The four-stroke engine
Inlet valve closed
Exhaust valve closed
POWER STROKE
Piston down powerfully
34
The four-stroke engine
Inlet valve closed
Exhaust valve closed
POWER STROKE
35
Exhaust

• Exhaust stroke the piston is travelling up
• Exhaust valve is open
• Intake valve is Closed
• Exhaust gases being pushed out by piston

36
The four-stroke engine
Inlet valve closed
Exhaust valve closed
EXHAUST STROKE
37
The four-stroke engine
Inlet valve closed
Exhaust valve open
Exhaust gases out
EXHAUST STROKE
38
The four-stroke engine
Inlet valve closed
Exhaust valve open
Exhaust gases out
EXHAUST STROKE
39
The four-stroke engine
Inlet valve open
Exhaust valve closed
INTAKE STROKE
40
And so the cycle continues!!
41
Exhaust system

• The exhaust system is needed to provide a pathway
  for exhaust fumes to be filtered and to reduce
  noise.
• Exhaust manifold
• Catalytic convertor
• Muffler

42
(No Transcript)
43
Recap

• What is the purpose of the compression stroke
  and what is happening
• What is the purpose of the power stroke and what
  is happening?
• What is happening during the exhaust stroke?
• What is the purpose of the exhaust system?

44
Video of 4 Stroke cycle
http//www.youtube.com/watch?vIYWUWMmimjQfeature
related http//videos.howstuffworks.com/auto/car
-parts-videos-playlist.htmvideo-30374
45
QUIZ
46
4 Stroke cycle

• http//www.youtube.com/watch?vYB_JCUw9SoUfeature
  related