DIS SYSTEMS

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DIS SYSTEMS
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Ignition Function

• Hot spark across spark plug gap
• Distributes high voltage to each plug in correct
  sequence
• Time the spark so it arrives as piston nearing
  TDC
• Adjusts spark timing with load speed

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Electronic Ignition Systems

• Uses electronic control circuit to fire ignition
  coil
• More dependable than contact system
• Higher secondary ignition voltages

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Magnetic Pickup Coil

• Produces tiny voltage pulses as magnetic field
  changes
• Trigger Wheel interrupts magnetic field
• Signals control unit to fire coil

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Computer Controlled Ignition Systems

• Produce maximum engine power fuel efficiency,
  reduced tailpipe emissions
• Ignition spark timing is continuously and
  accurately adjusted

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Magnetic Pulse Generator

• Wire wrapped around a weak magnet, timing disk
  mounted to the crank or cam shaft. Disk has
  points or windows that interrupt the magnetic
  field. AC voltage induced is sent to control
  module to fire coil.

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MP Generator Waveform
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Hall-Effect Sensor

• Works similar to MPG
• Voltage generated at all times
• Rotating shutters interrupt the voltage, turning
  off the voltage
• Schmitt trigger cleans up the signal converts
  it to a square wave (digital) signal

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Crankshaft Sensor
(CKP)
Measures crankshaft RPM
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Dual Crankshaft Sensor
Represents 1 cylinder
Represents each cylinder

• Two sensors in one

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Distributorless Ignition Systems

• No Distributor
• One coil per two cylinders (waist spark)
• One coil per cylinder (coil over plug)
• Ignition Module synchronizes the firing sequence
  in relation to crankshaft position
• Ignition module signals ECM when to control each
  fuel injector
• Ignition module provides tachometer signal

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Cylinder Arraignment
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Waist Spark

• One coil per two cylinders

• 4
• Exhaust
• Stroke
• 1
• Comp.
• Stroke

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Coil Over Plug
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GMs C3 Ignition System
Ignition Control Module
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Knock Sensor

• Mounted in engine block
• Detects preignition and detonation
• Vibrations create a small AC voltage which is
  sent to ignition module or ECM
• Computer determines if voltages are frequent
  enough, if so, timing is retarded