Internal Combustion Engine
Engr. Mansoor Ali Zaheer
Assistant Professor
Mechanical Engineering Department
University of Sargodha
IGNITION SYSTEMS OF IC ENGINES
What is Ignition System ?
➢ The system in an internal-combustion engine that produces
the spark to ignite the mixture of fuel and air: includes the
battery, ignition coil, distributor, spark plugs, and associated
switches and wiring.
➢ Ignition system, in a gasoline engine, means employed for
producing an electric spark to ignite the fuel–air mixture; the
burning of this mixture in the cylinders produces the motive
force.
Requirement of Ignition System
• A smooth and reliable functioning of an ignition system is essential for
reliable working of an engine.
• The requirements of such an ignition system are:
1.It should provide a good spark between the electrodes of the plugs at
the correct timing.
2.It should function efficiently over the entire range of engine speed.
3.It should be light, effective and reliable in service.
4.It should be compact and easy to maintain.
5.It should be low cost and convenient to handle.
6.The interference from the high voltage source should not affect the
functioning of the radio and television receivers inside all automobile.
Battery Ignition System Magneto Ignition System Electronic Ignition System
1. Battery Ignition System
Construction
It consists of the following parts:
Battery(Lead Acid type)
▪ Stores the Electrical Energy.
▪ Charges using the Dynamo
driven by the engine
Ignition switch
▪ Helps in turning the system ON or
OFF
Ballast Resistor
▪ Under prolonged conditions it
helps to maintain the temperature
of Ignition Coil
▪ It is provided in series with
primary winding to regulate
primary current.
▪ For starting purposes, this resistor
is bypassed so that more current
can flow in primary circuit.
Ignition coil
▪ Steps up the Low Voltage to High
Voltage to induce an electric spark
in the spark plug.
▪ 2 sets of windings
▪ Primary windings
▪ Secondary windings
▪ Iron core
▪ Produces magnetic field
▪ Contact breaker
Making and breaking
the primary circuit.
Capacitor or Condenser
▪ Prevents the burning and
possible welding of metal
points.
Distributor
▪ Distributes the Ignition surge to
individual spark plugs.
Spark plug
▪ Creates the spark due to
ionization of gap
Working
Advantages
7. Contact breaker points are absent-so no arcing.
8. Spark plug life increases by 50% and they can be used for about 60000
km without any problem.
9. Better combustion in combustion chamber, about 90-95% of air fuel
mixture is burnt compared with 70-75% with conventional ignition system.
Disadvantages
Application
1. It is used in all S.I. engines used in modern vehicles.
2. It is used in engines in industries which requires sparking for combustion.
2. Magneto Ignition System
Magneto Ignition System
Magneto Ignition System
Magneto Ignition System
Difference between Battery and Magneto Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
Electronic Ignition System
IGNITION SYSTEM TROUBLESHOOTING
Problem Possible causes and/or solutions
No spark out of the coil Possible open in the ignition switch circuit
Possible defective ignition module (if electronic
ignition coil) Possible shorted condenser
Weak spark out of the coil Possible high-resistance coil wireor spark plug wire
Possible poor ground between the distributor or
module and the engine block
Engine missing Possible defective (open) spark plug wire Possible
worn or fouled spark plugs Possible defective
pickup coil Possible defective module
Possible poor electrical connections at the pickup
coil and/ormodule
