2. Primary Ignition

3. Induction n We n We have learned that electricity can create magnets. Called _____________? n Now n Now we are going to talk about magnets creating electricity. n Keep n Keep them straight Electromagnets

4. Induction n Creating voltage with a magnetic field –Three things needed for induction »Magnetic field »Conductor »Relative movement Here we are moving a Conductor through a magnetic Field, inducing voltage into The conductor.

5. D.C. Voltage If we kept moving the conductor thru the magnetic Field the same way at an even speed, this is the kind Of voltage we would induce in the conductor Voltage pushing the same way all the time pushes current only one way

6. Induction Here we are moving the magnetic field past the conductor Inducing voltage into the conductor

7. A.C. Voltage Voltage created first one way, then the other pushes current back and forth House A.C. voltage used in the United States Changes direction 60 times a second (60Hz) Frequency is measured in Hertz (Hz) 1 Hertz (Hz)

8. Induction review n Anytime n Anytime a magnetic field is moving past a conductor, voltage is induced induced into the conductor n Can n Can be increased by: –Larger –Larger magnetic conductor –Faster –Faster movement –Closer –Closer distance I’ve got it

9. Mutual Induction n Voltage induced from one winding into another n Only happens when magnetic field is building or collapsing

10. Watt’s Law n Power (watts) is equal to Volts times Amps P VI

11. Mutual Induction (stepped up) Remember your Briggs & Stratton Ignition Coil in Auto 1? Approximately 150 windings in Primary and 9000 in secondary Approximately a 1:60 ratio

12. Mutual Induction (stepped down) Typical step down transformer Same amount of energy - Reduced the voltage by 10 Increased the amperage by 10

14. 13,800 volts pushing Current in through These two wires Transformer stepping Down the voltage to 240 A.C. volts and Increasing the amps Wire to my house Wires to all my six neighbors houses on the block Compare the wire Sizes coming in and Going out

15. Common transformer Input = 120 VAC 5 W 42 mA Output = 12VDC 24W 200 mA

16. Self Induction n Voltage n Voltage induced back into the winding that created the magnetic field when the field is shut off (collapsed) Usually 200 V to several thousand volts are self induced. Depends on the number of turns and the speed of collapse

17. Self Induction n 12 Volts won’t but this amount Can shock you!

18. Self Induction in a Relay n When current is shut off to winding to open relay, self induction will take place. –Voltage spike can easily damage a computerized controlled circuit –The high voltage will naturally be built opposite to the voltage that created it

19. Clamping Diode n Diode is a one-way electrical check valve –We will learn how they work later in the year –Allows current only to flow one way »The way the arrow points

20. What we have learned and used so far –Ohm’s –Ohm’s Law, Watt’s Law –Circuits »Components, Series, parallel (ATECH 1-11) –Problem –Problem circuits »Open, »Open, high resistance, short, grounded, short to voltage, low voltage (ATECH 7 & 11) –Meters »How »How to read, use, how to find faults (ATECH 1-11) –Wiring –Wiring schematics »How »How to read, draw, interpret symbols, and trace (ATECH 4-11) –How –How magnetism and electricity relate »Electromagnets, »Electromagnets, Relays, Induction

21. Ignition n Lets take what we know and apply it to one specific circuit in the automobile

22. Primary Ignition circuit n Used to make spark for Power Stroke –Changes the 12 volts in the battery into as much as 50,000 volts for the spark at the spark plugs n This is easier than our Briggs & Stratton engines last year. –We started with no voltage and created as much as 15,000 volts all by starting with a magnetic in the flywheel moving past an armature and coil assembly (Magneto Ignition System) »Used today on many race cars so they don’t have to carry the weight of a battery

23. Primary Ignition Schematic (point type) Fill it in on your handout Battery Ignition switch Ballast resistor Points Coil Condenser Distributor

24. Primary Ignition Parts n Battery –Supplies voltage to circuit to push current flow n Ignition Switch –Turns on and off circuit n Resistor –Uses up voltage and lowers current flow n Coil –Step up voltage

25. Primary Ignition Parts n Distributor contains: –Points »Switch on and off primary circuit for proper spark timing –Condenser »Absorbs electrons when points are opening

26. Ignition Coil Has two windings: Primary wrapped around The Secondary Both Windings wrapped around an iron core

27. Ignition Coil Positive Terminal Labeled: “+” “Batt” Negative Terminal Labeled: “-” “Dist” Fill it in on your handout Primary Winding Connects from + to – inside coil Has about 200 windings Standard resistance is 1.5 ohm (+- 1) Approximately 200V are created during self induction Secondary Winding Connects from – to center of coil Has about 25,000 windings Standard Resistance is 8,500 to 12,000 ohms Can create approximately 30,000 volts (30 KV) Coil wrapped in metal shield, insulated inside with, glass, tar, epoxy, oil

28. Shorted Coil

29. Saturation Turn on point Saturation point Turn on point Saturation point Two coil ramps Taken with a Lab Scope and An amp probe. Shorted coil About 4.25 mS

30. Primary Ignition Operation Turn Key On Points Closed 12 V in Battery will push ______ amps through primary circuit 1.5 ohms 4 In 3 to 5 mS, a large magnetic field is formed around primary winding

31. Primary Ignition Operation Turn Key On Points Opened 12 V in Battery will push ______ amps through primary circuit 1.5 ohms 0 The magnetic field will collapse rapidly and induce high voltage into secondary 25,000 Volts

32. Demo Time Hey, I have got To see that in Real life. It can’t be that simple!

33. Primary Ignition Review n Key n Key on, points closed –Current –Current flows, magnetic field builds up n Points n Points open –Current –Current stops flowing as condenser absorbs electrons that want to jump gap –Magnetic –Magnetic field collapses moving rapidly past secondary windings –High –High voltage is induced induced into secondary windings –We –We have spark

34. Questions?

35. What opens the points? n What n What we need is a mouse in the distributor to push open the points every time we need spark for every cylinder? What happens when I get tired?

36. What really opens the points? n Points are opened by a “cam” in the distributor n Distributor is driven by the Camshaft n Camshaft and distributor are at a 1:1 ratio n Distributor is at half speed of crankshaft

37. Dwell & 4 cyl. distributor cam n Dwell is the time in degrees the points are closed n Measured in degrees of distributor rotation n 4 cylinder distributor cam has four sides n Maximum dwell (points always closed) is 90 o 90 o x 4 360 o n Specs. Usually call for 35 o to 55 o

38. Questions n If the distributor for a 4 cylinder makes one revolution, how many times will the points open? n What happens every time the points open after current has been flowing through them? n How far will the crankshaft have turned

39. 6 cylinder distributor cam n Distributor n Distributor cam has 6 sides (hex) n Maximum n Maximum dwell is ________ degrees 60 o n Specs. Usually call for 30 o to 40 o

40. 6 cylinder Distributor cam

41. 8 cylinder distributor cam n Has 8 sides (octagon) n Maximum dwell is 45 o n Specs. Usually call for 26 o to 32 o

42. 8 cylinder distributor cam 30 degrees of dwell, 15 degrees of point opening

43. Why a minimum Dwell? n Points n Points have to be closed long enough to reach magnetic field saturation in coil. –No –No problem at low speed but is at high speed. –For –For an 8 cylinder, 6000 RPM RPM is about maximum RPM with point type ignition n Ready n Ready to try to earn 10 extra credit points? –To –To earn, you are going to have to apply what you have learned up to now.

44. Extra Credit n Tear out a piece of paper, put name on top n Must show ALL your work to get any credit. –No calculator n No talking or looking at anyone’s paper to get credit n You have 4 minutes starting now

45. n How many times are the points opening per second at 6000 RPM on an 8 cylinder engine?

46. Time is up

47. Answer n Need to know to figure this out –Engine RPM is measured in Crankshaft speed –Distributor turns half crank speed »6000 divided by 2 = 3000 distributor RPM –In one distributor revolution the points open eight times on an 8 cylinder »3000 times 8 = 24,000 point openings per minute –There are 60 seconds in a minute »24,000 divided by 60 = 400 Point openings per second at 6000 RPM

48. 8 cylinder dual point distributor

49. Point float n Must have good point spring tension or points will not close (float) when they are suppose to

50. Why a Maximum Dwell n What would happen if we set the dwell to 44 o n Don’t forget to lubricate points when renewing

51. How to hook up Dwell Meter n Red lead to “-” side of coil n Black lead to ground n Select proper number of cylinders n Can read while cranking or running n Might change a few degrees between cranking and running

52. Dwell and Points Review n Dwell must be long enough in time for coil to saturate at high speed n Points must open enough so when condenser gets filled, points won’t ark n Point spring tension must be good so points won’t float at higher RPM n Point contacts must be good so there isn’t any resistance across (cause voltage drop) n Maximum dwell is 90 o for 4 cylinder, 60 o for a 6 cylinder, and 45 o for an 8 cylinder

53. Questions? Yea Dude, How do you set timing?