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Automotive Ignition Systems

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Presentation on theme: "Automotive Ignition Systems"— Presentation transcript:

1 Automotive Ignition Systems

2 Ignition System Purpose
Create a high voltage spark Deliver the spark at correct time To create a high voltage spark of 20,000 volts or more Deliver the spark to the right cylinder at the right time in the four strokes of each piston in the engine

3 How Stuff Works .com

4 Ignition Timing BTDC ATDC Engine RPM Engine Load Firing Order Retard
Advance Before top dead center After top dead center Engine RPM Engine Load Firing order

5 Firing Order

6 Firing Order 1,3,4,2 1,2,5,4,3,2 1,5,6,3,4,2,7,8

7 Firing Order

8 Ignition System Circuits
Primary Circuit (Low Voltage) Ignition Switch Resistor Coil Primary Winding Ignition Module Pick-up Assembly Secondary Circuit (High Voltage) Coil Secondary Winding Coil Wire Distributor Cap & Rotor Plug Wires Spark Plugs Primary Circuit Secondary Circuit Ignition Switch Coil Secondary Winding Resistor Coil Primary Winding Ignition Module Pick-up Assembly

9 Ignition Primary Circuit
Battery Ignition Switch Resistor Coil Winding Ignition Module Pick-up Assembly Low voltage side

10 Ignition Coils Step-up transformer Primary winding Secondary winding
Uses electro-magnetic induction to operate Magnetic field must be built up and then collapsed

11 Ignition Coil High Voltage wire + Battery - ign module
Primary Windings Secondary Windings

12 Making & Breaking Fields

13 Ignition Modules Old Systems Used Breaker Points
Modules Contain a Switching Transistor Externally Mounted Distributor Mounted

14 Ignition Pick-up Assemblies
Can be mounted in one of five different locations: #1 Distributor #2 Vibration Damper #3 Flywheel #4 Crankshaft #5 Camshaft

15 Distributor A mechanical timing device Drives off engine camshaft
Can controls both primary and secondary circuits May contain advance units

16 The Rotor at Work Rotates around to DISTRIBUTE voltage to each spark plug

17 Ignition Secondary Circuit
Coil Winding Coil Wire Distributor Cap & Rotor Spark Plug Wire Spark Plug

18 Distributor Cap & Rotor
Cap fits on top of the distributor housing Made of lexon plastic Has an index mark for proper installation Rotor fits on top of distributor shaft Also is indexed

19 Spark Plug Wires Very high resistance wire 1000 ohms per inch
Mostly insulation material Small conductor material Must follow firing order

20 Spark Plug Placement                                                       

21 Spark Plugs Shell w/threads Ceramic insulator Center electrode
Side electrode Plug gap Heat range Plug designation

22 Resistor Plugs

23 Heat 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.

24 Spark Plugs tell a story
Normal Worn Lead Erossion Insulator Breakage Minor Melting Carbon Over Heating Fuel/Additive Deposits Lead Fouled Oil

25 Old Breaker Point Ignition
Used 1920’s mechanical switch in distributor build-up - collapse coil magnetic field Points wear out Must be replaced each year

26 Breaker Point (dwell angle)

27 Breaker Point Parts                     

28 Making & Collapsing field

29 Electronic Ignition with Distributor (HEI)
Transistor in ignition module turns coil on/ off Module mounted externally or in distributor Pick-up in distributor

30 High Energy Ignition (HEI)

31 Trigger Wheel No Points Rotating Reluctor Wheel Fewer Tune-Ups
More Efficient

32 Optical Trigger (Chrysler)
Photo Electric Sensor (Photo = Light)

33 CKPS (crankshaft position sensor)
Fewer Parts No Points No Distributor No Rotor Computer Controlled More Efficient

34 Crank Trigger Wheel

35 Direct Ignition No Distributor One Coil for Two Cylinders
Waste Spark System One Plug Fires Backwards

36 Wasted Spark 1st plug fires forward 2nd fires backwards
Sister cylinders

37 Direct Ignition

38 Coil Over                                                       

39 Business End of the Ignition System
Size Reach Heat Range Spark.Air Gap

40 Ignition System Maintenance
Replace Spark Plugs every 30,000mi/36mo Inspect Cap and Rotor (replace if necessary) Inspect Spark Plug wires (replace if necessary) Check Firing Order Check Ignition Timing (if necessary)

41 Timing Engine Warm At Idle Defeat Advance #1 Plug wire



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