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