Presented by:

DEEPAK KUMAR

+91-8950783197

Introduction

•This system is powered by a lead-acid battery to provide a constant source of electricity, magneto systems were abandoned for systems which interrupted current at battery voltage, used an ignition coil and a distributor to route the ensuing pulse to the correct spark plug at the correct time to start a engine use in Petrol cars.

Ignition Circuit Diagram -Mechanically Timed Ignition

Spark plug A spark plug is a device for delivering electric

current from an ignition system to the combustion chamber of a spark-ignition engine to ignite the compressed fuel/air mixture therein by means of an electric spark, while containing combustion pressure within the engine. A spark plug has a metal threaded shell,

electrically isolated from a central electrode by a porcelain insulator. The central electrode, which may contain a resistor, is connected by a heavily insulated wire to the output terminal of an ignition coil or magneto. The spark plug's metal shell is screwed into the engine's cylinder head and thus electrically grounded.

Ignition coil An ignition coil (also called a spark coil) is an induction coil in an automobile's ignition system which transforms the battery's low voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel. Some coils have an internal resistor while others rely on a resistor wire or an external resistor to limit the current flowing into the coil from the car's 12 volt supply. The wire which goes from the ignition coil to the distributor and the wires which go from the distributor to each of the spark plugs are called spark plug wires or high tension leads.

Distributor A distributor is a

device in the ignition system of an internal combustion engine that routes high voltage from the ignition coil to the spark plugs in the correct firing order.

Distributor Cap

•Insulated plastic cap

•Transfers voltage from coil (wire) to Rotor.

Ignition TimingHow early or late the spark plug fires in relation to the position of theengine piston.

Ignition timing must change with the changes in engine speed, load, and temperature.

Ignition TimingTiming Advance occurs when the plug fires sooner on compressionstroke (High engine speed)

Timing Retard occurs when plug fires later on compression stroke(Lower engine speed)

BASE TIMING Timing without vacuum or computer control.

Methods of controlling TimingVacuum Advance

•Controlled by engine intake manifold vacuum and engine load.

•The vacuum diaphragm rotates the pickup coil against the direction of distributor shaft rotation.

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