Automotive Automotive Ignition Ignition SystemsSystems

Ignition System Ignition System PurposePurpose

Create a high voltage spark Create a high voltage spark Deliver the spark at correct timeDeliver the spark at correct time

HHoow w StStufuff f WWororksks . .cocomm

Ignition TimingIgnition Timing

BTDCBTDC ATDCATDC Engine RPMEngine RPM Engine LoadEngine Load Firing OrderFiring Order RetardRetard AdvanceAdvance

Firing OrderFiring Order

Firing OrderFiring Order

1,3,4,21,3,4,2

1,2,5,4,3,21,2,5,4,3,2

1,5,6,3,4,2,7,81,5,6,3,4,2,7,8

Firing OrderFiring Order

Ignition System CircuitsIgnition System Circuits

Primary CircuitPrimary Circuit (Low Voltage)(Low Voltage)

Ignition SwitchIgnition Switch ResistorResistor Coil Primary Coil Primary

WindingWinding Ignition ModuleIgnition Module Pick-up AssemblyPick-up Assembly

Secondary Secondary CircuitCircuit (High Voltage)(High Voltage)

Coil Secondary Coil Secondary WindingWinding

Coil WireCoil Wire Distributor Cap & Distributor Cap &

RotorRotor Plug WiresPlug Wires Spark PlugsSpark Plugs

Ignition Primary CircuitIgnition Primary Circuit BatteryBattery Ignition SwitchIgnition Switch ResistorResistor Coil WindingCoil Winding Ignition ModuleIgnition Module Pick-up AssemblyPick-up Assembly Low voltage sideLow voltage side

Ignition CoilsIgnition Coils

Step-up Step-up transformertransformer

Primary windingPrimary winding Secondary windingSecondary winding Uses electro-Uses electro-

magnetic induction magnetic induction to operateto operate

Magnetic field Magnetic field must be built up must be built up and then collapsedand then collapsed

Ignition CoilIgnition Coil High Voltage wireHigh Voltage wire + Battery+ Battery - ign module - ign module Primary WindingsPrimary Windings Secondary Secondary

WindingsWindings

Making & Breaking FieldsMaking & Breaking Fields

Ignition ModulesIgnition Modules

Old Systems Used Old Systems Used Breaker PointsBreaker Points

Modules Contain Modules Contain a Switching a Switching TransistorTransistor

Externally Externally MountedMounted

Distributor Distributor MountedMounted

Ignition Pick-up Ignition Pick-up AssembliesAssemblies

Can be mounted in one of five different locations:

#1 Distributor#2 Vibration Damper#3 Flywheel#4 Crankshaft#5 Camshaft

DistributorDistributor

A mechanical A mechanical timing devicetiming device

Drives off engine Drives off engine camshaftcamshaft

Can controls both Can controls both primary and primary and secondary circuitssecondary circuits

May contain May contain advance unitsadvance units

The Rotor at WorkThe Rotor at Work

Rotates around to Rotates around to DISTRIBUTE DISTRIBUTE voltage to each voltage to each spark plugspark plug

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Ignition Secondary Ignition Secondary CircuitCircuit

Coil WindingCoil Winding Coil WireCoil Wire Distributor Cap & Distributor Cap &

RotorRotor Spark Plug WireSpark Plug Wire Spark PlugSpark Plug

Distributor Cap & RotorDistributor Cap & Rotor

Cap fits on top of the Cap fits on top of the distributor housingdistributor housing

Made of lexon plasticMade of lexon plastic Has an index mark Has an index mark

for proper for proper installationinstallation

Rotor fits on top of Rotor fits on top of distributor shaftdistributor shaft

Also is indexedAlso is indexed

Spark Plug WiresSpark Plug Wires

Very high Very high resistance wire resistance wire 1000 ohms per 1000 ohms per inchinch

Mostly insulation Mostly insulation materialmaterial

Small conductor Small conductor materialmaterial

Must follow firing Must follow firing orderorder

Spark Plug PlacementSpark Plug Placement

                                           

           

Spark PlugsSpark Plugs

Shell w/threadsShell w/threads Ceramic insulatorCeramic insulator Center electrodeCenter electrode Side electrodeSide electrode Plug gapPlug gap Heat rangeHeat range Plug designationPlug designation

Resistor PlugsResistor Plugs

Heat Rages of PlugsHeat Rages of Plugs

The difference between a "hot" and a "cold" spark plug

is in the shape of the ceramic tip.

The difference between a "hot" and a "cold" spark plug is in the shape of the ceramtip.

The carmaker will select the right-temperature plug for each car. Some cars with high-performance engines naturally generate more heat, so they need colder plugs. If the spark plug gets too hot, it could ignite the fuel before the spark fires; so it is important to stick with the right type of plug for your car.

Spark Plugs tell a storySpark Plugs tell a storyNormal Worn Lead Erossion Insulator Breakage

Minor Melting

Over HeatingCarbon

Fuel/Additive Deposits

Lead FouledLead Fouled Oil

Old Breaker Point Old Breaker Point IgnitionIgnition

Used 1920’s - Used 1920’s - 19741974

mechanical switch mechanical switch in distributor in distributor

build-up - collapse build-up - collapse coil magnetic fieldcoil magnetic field

Points wear out Points wear out Must be replaced Must be replaced

each yeareach year

Breaker Point (dwell Breaker Point (dwell angle)angle)

Breaker Point PartsBreaker Point Parts

                    

Making & Collapsing fieldMaking & Collapsing field

Electronic Ignition with Electronic Ignition with Distributor (HEI)Distributor (HEI)

1970’s1970’s Transistor in Transistor in

ignition module ignition module turns coil on/ offturns coil on/ off

Module mounted Module mounted externally or in externally or in distributordistributor

Pick-up in Pick-up in distributordistributor

High Energy Ignition (HEI)High Energy Ignition (HEI)

Trigger Trigger WheelWheel

No PointsNo Points Rotating Reluctor Rotating Reluctor

WheelWheel Fewer Tune-UpsFewer Tune-Ups More EfficientMore Efficient

Optical Trigger (Chrysler)Optical Trigger (Chrysler) Photo Electric Photo Electric

SensorSensor (Photo = Light)(Photo = Light)

CKPSCKPS (crankshaft position (crankshaft position

sensor)sensor) Fewer PartsFewer Parts No PointsNo Points No DistributorNo Distributor No RotorNo Rotor Computer Computer

ControlledControlled More EfficientMore Efficient

Crank Trigger WheelCrank Trigger Wheel

Direct IgnitionDirect Ignition

No DistributorNo Distributor One Coil for Two One Coil for Two

CylindersCylinders Waste Spark Waste Spark

SystemSystem One Plug Fires One Plug Fires

BackwardsBackwards

Wasted SparkWasted Spark

11stst plug fires plug fires forwardforward

22ndnd fires fires backwardsbackwards

Sister cylindersSister cylinders

Direct IgnitionDirect Ignition

Coil OverCoil Over

                                           

           

Business End of the Business End of the Ignition SystemIgnition System

SizeSize ReachReach Heat RangeHeat Range Spark.Air GapSpark.Air Gap

Ignition System Ignition System MaintenanceMaintenance

Replace Spark Plugs every Replace Spark Plugs every 30,000mi/36mo30,000mi/36mo

Inspect Cap and Rotor (replace if Inspect Cap and Rotor (replace if necessary)necessary)

Inspect Spark Plug wires (replace if Inspect Spark Plug wires (replace if necessary)necessary)

Check Firing OrderCheck Firing Order Check Ignition Timing (if necessary)Check Ignition Timing (if necessary)

TimingTiming

Engine WarmEngine Warm At IdleAt Idle Defeat AdvanceDefeat Advance #1 Plug wire#1 Plug wire