This document discusses ignition and cooling systems for internal combustion engines. It describes the basic components and processes of spark ignition and battery ignition systems, including magnetos, coils, distributors and spark plugs. It also explains the four-stroke engine cycle and identifies the purpose of engine cooling to maintain optimal temperatures. The key cooling system types - air, hopper water, thermosiphon and forced circulation water cooling - are outlined.

1. IGNITION SYSTEM AND COOLING SYSTEM
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag.
Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

2. LESSON OUTCOMES
 Identify the basic components of different ignition
systems and cooling systems
 Describe the processes in ignition systems and cooling
systems
 Describe the importance of engine cooling system
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

3. IC ENGINE: FOUR-STROKE CYCLE

4. IGNITION SYSTEM

5. TYPES OF IGNITION SYSTEMS
 Ignition by electric spark or spark ignition
 Ignition by heat of compression or compression
ignition
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

6. SPARK IGNITION
 Purpose: deliver a perfectly timed surge of electricity
across an open gap in each cylinder at the exact moment
 Types of spark ignition
a) Magneto ignition
b) Battery ignition
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

7. MAGNETO IGNITION SYSTEM
 Magneto is used to
generate electric current
for producing spark
 A high tension magneto
generates a very high
voltage and transfer that
voltage to the spark plug
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

8. MAGNETO IGNITION SYSTEM – MAIN COMPONENTS
 Rotating Magnets
 Primary Winding
 Secondary Winding
 Fixed Armature
 Capacitor
 Breaker-points or
Contact Breaker
 Distributor
 Ignition Switch
 Spark Plug
CAPACITOR
IGNITION
SWITCH
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

9. MAGNETO IGNITION SYSTEM
CAPACITOR
IGNITION
SWITCH
Rotating magneto: Produce the energy in the
form of high voltage
Fixed armature: Carries alternating current
Primary winding: Draws power from the source
Secondary winding: Change the voltage of the load
Capacitor: Store the charger
These breaker points and the capacitor produce an increase in the rate of change
of magnetic flux. When the breaker points are opened by the cam mounted on
the rotor shaft, the capacitor gets charged by currents from the primary coil.
Distributor: route secondary voltage from the
ignition coil to the spark plug so that the correct
firing order and correct timing happens
Ignition switch: controls
the magneto ignition
Spark plug: Ignite the fuel
air mixture

10. WORKING PRINCIPLE
CAPACITOR
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

11. BATTERY IGNITION
High-voltage circuit
 secondary winding
 distributor rotor
 spark plugs
Low-voltage circuit
 battery
 ignition switch
 primary winding
 contact breaker
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

12. WORKING
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

13. BATTERY IGNITION SYSTEM ON A MODERN TRACTOR
 battery
 ignition switch
 ballast resistor
 ignition coil
 distributor
 contact breaker
 capacitor
 spark plugs
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

14. SPARK PLUG
 Ignites the air–fuel mixture in combustion
chamber
 Usually the spark plug gap settings are kept
between 0.5 and 0.85 mm
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

15. IGNITION COIL
 Serves the purpose of a
small transformer, which
sets up low voltage to very
high voltage
 Sealed to prevent entry of
moisture
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

16. FIRING ORDER
Crank shaft
degree
Cylinders
0 1 2 3 4
180 Power stroke Exhaust Compression Suction
360 Exhaust Suction Power stroke Compression
540 Suction Compression Exhaust Power stroke
720 Compression Power stroke Suction Exhaust
4-Cylinder
1-3-4-2
1-2-4-3
6-Cylinder
1-5-3-6-2-4
• Sequence in which the power is produced in an engine – obtain best performance
• Cylinder nearest the radiator is designed as number 1
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

17. COOLING SYSTEM
 Temperature produced on the power stroke of an engine
can be as high as 1600ºC > melting point of engine parts
30%
coolin
g
syste
m
40%
exhaust
30%
useful
power
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

18. PURPOSE OF COOLING
 To maintain optimum temperature of engine for efficient operation
under all conditions
 To dissipate surplus heat for protection of engine components like
cylinder, cylinder head, piston, piston rings and valves
 To maintain the lubricating property of the oil inside the engine
cylinder for normal functioning of the engine
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

19. AIR COOLING SYSTEM
 Heat is conducted from the working components
of the engine to the atmosphere directly
 Air circulates by air blower/fan
 Fins increase the area of contact of air for speedy
cooling
 Size and spacing depend on - the amount of heat to be
removed, temperature of air, speed of air, material type, spacing
between the fins, cylinder size
 Large number of short fins are considered to be better
than small number of large fins
 Higher pressure of air is required when the spacing
between the fins is reduced
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

20. AIR COOLING SYSTEM
 Advantages:
 Comparatively lighter
 Simpler in design and
construction
 Can use in extreme weather
conditions
 Disadvantages:
 Uneven cooling of the engine
parts
 Engine temperature is generally
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

21. WATER COOLING SYSTEM
 Use water as cooling medium
 Water - circulate round the cylinders to absorb heat from the cylinder
walls
 Heated water is conducted through a radiator to remove the heat and
cool the water
 Methods:
1. Open jacket or hopper method
2. Thermo-siphon method
3. Forced circulation method
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

22. HOPPER WATER COOLING SYSTEM
 Hopper or jacket containing water
that surrounds the engine cylinder
 As soon as the water starts boiling,
it is replaced by cold water.
 The hopper is large enough to run
for several hours without refilling.
 A drain plug is provided in a low
accessible position for draining
water as and when required
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

23. THERMO-SIPHON WATER COOLING SYSTEM
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

24. FORCED CIRCULATION COOLING SYSTEM

25. FORCED CIRCULATION COOLING SYSTEM

26. COOLING SYSTEM HT OPERATION
Engine heat is transferred . . .
 through walls of the combustion chambers
 through the walls of cylinders
Coolant flows . . .
 through the upper radiator hose
 through radiator
 to water pump
 through engine water jackets
 through thermostat
 back to radiator
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

27. RADIATOR
 Type of heat exchanger
 Hot water flows into the radiator at the top
and cold water flows out from the bottom
 Tubes or passages carry the water from the
top of the radiator to the bottom, passing it
over a large metal surface
 Air flows between the tubes or through the
cells at right angles to the downward flowing
water
 This helps in transferring the heat from the
water to the atmosphere
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

28. TYPES OF RADIATOR
 On the basis of fabrication:
 Tubular type radiator
 Cellular type radiator/honeycomb radiator
Tubular type
Cellular type
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)

29. ANTIFREEZE MIXTURE/COOLANT
 Ethylene glycol
 Propylene glycol
 Diluted (usually 50/50 with distilled
water) antifreeze
 Prevents water from freezing
 Avoid over-heating (summer time)
 Keep the cooling system clean
Dr. (Ms.) Jayaruwani Fernando, Ph.D. (Ag. & Biosystems Engineering), M.S. (Industrial and Ag. Technology), M.Phil. (Ag. & Biosystems Engineering), B.Sc. (Agriculture)