Systems Repair Worksheet



Systems Repair Worksheet Chapter 27 Pages 810-835 Name      

Ignition Systems 68 Points Due Date      

1. The system provides the properly timed, high voltage surges to ignite the A/F

mixture in the cylinders. Improper ignition affects fuel economy, performance & emissions.

2. Ignition system designs are either distributor, (coil pack) or (coil-on-plug).

3. The circuit is the low voltage circuit and the is the high

voltage ignition system circuit. The primary is also the low resistance coil & secondary the high resistance coil.

4. Battery current is switched on by the to supply the primary circuit.

5. When the field in the primary ignition coil through the

secondary ignition coil windings, a high voltage surge is generated (induced) & then sent to the plugs.

6. Older ignition systems used a resistor or a calibrated resistance wire to act as a

voltage drop in the primary circuit, limiting full charging voltage from reaching the primary coil.

7. The circuit carries the high voltage to the spark plugs.

8. In a distributor system, the & deliver the sparks top the wires in the correct order.

9. EI systems, either wasted spark or direct, have firing current & spark duration.

10. An ignition is a pulse that has two coils of wire wrapped around

an iron core. Primary coil = 100-200 turns of AWG 20 wire. Secondary = 15,000-20,000 turns of very fine wire.

11. Iron or steel cores are used in ignition coils to reduce to magnetic lines of force.

12. is the name given to the length of time the primary current flows in order to saturate

the coil primary windings with magnetic fields…often now just called “coil saturation time”.

13. is the term used to describe temporary resistance to current flow in the primary

coil caused by magnetic field interference. This is the “F” in LSMFT (5 causes of resistance in a path).

14. A coil with magnetism will have more potential to produce its designed voltage.

15. Secondary coil windings are wound on the of the primary windings. collapse inward

16. The difference between the voltage required to the plugs and the maximum

voltage, is called secondary reserve voltage. This reserve is designed to prevent misfire.

17. The spark plug is where high voltage causes the arc needed to ignite the A/F mix.

18. on the insulator prevent electric arcing on the outside of the spark plug.

19. Spark plugs have either an mm or a 14 mm diameter thread sealed with either a steel washer

or a tapered seat. Tightening specs differ depending upon the sealing method used.

20. Thread (length) is crucial to properly position electrode gap in the combustion chamber.

21. As heat range goes, a cold plug has a nose and a hot plug has a insulator nose.

22. - type spark plugs have a 5kΩ internal resistor used to suppress RFI.

23. The used in electrode construction determine a spark plug’s longevity, power &

efficiency. Electrode materials include copper-nickel alloys, platinum, iridium, and yttrium.

24. V-groove, U-groove & pin-point designs require lower firing voltages.

25. Television & Radio Suppression (TVRS) plug wiring uses carbon impregnated

cores without actual wire inside. This is done to lower RFI & EMI.

26. Electronic ignition systems switch the current on & off using an NPN transistor.

The emitter is connected to ground, the collector to the coil negative terminal & the base is

switched with a triggering device to interrupt (switch) the ground side of the primary coil.

27. Sensors, like the CKP & CMP, are used to trigger the NPN. These sensors can be

pulse generators, sensors, sensors & metal detection sensors.

28. Magnetic pulse generators consist of a coil & a trigger wheel called a .

These are also known as PM generators because they contain permanent magnets.

29. Metal detection sensors use pick-up coils with instead of permanent magnets.

30. The Hall-effect sensor is the most popular type of engine position sensor due to its

voltage signal throughout the entire engine rpm range and its ability to produce a square wave.

31. Photoelectric sensors use diodes and photo transistors as triggers.

32. Adjusting the that spark happens is critical to efficient engine operation.

33. Ignition timing is specified by relating the position of piston to degrees of crank rotation.

34. Spark timing that is called “0” occurs at exactly at the end of the stroke.

35. Both sensitive (vacuum) and sensitive (mechanical) devices have been used to

change the timing of the spark. The PCM uses MAP (load) CKP (speed) sensors as timing inputs.

36. Distributors may contain an integral as well as an integral .

37. Distributorless (EI) systems are either spark or -over-cylinder designs.

38. EI systems eliminate parts that caused resistance and needed maintenance, reduced ,

increased time for saturation, allow individual control of cylinders, and operate cooler.

39. On spark (double-ended coils), one coil is connected in series with two spark plugs.

40. cylinders fire simultaneously, 1 on compression (event) & 1 on exhaust stroke (waste).

41. Coil-per-cylinder ignition (direct) can be coil- -plug or coil- -plug.

42. On any ignition system design, timing at each cylinder can be individually changed for maximum

performance. True False

43. Some engines have 2 spark plugs per cylinder. True False

44. Some engines can fire multiple sparks from the same plug on one stroke. True False

45. Engine position sensors used for spark triggering can also be used to detect .

46. Spark timing corrections are made to engines in an effort to compensate or correct:

|coolant |engine |

|stabilizing engine | operation |

| correction | control |

| control correction | |

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