Navigation%20Instructions

1
Navigation Instructions

• You will need to become familiar with these
  buttons to navigate this lesson.

The forward button will go forward one screen.
Click this button when you are ready to proceed
from this screen. Notice the cursor change.
When your mouse cursor changes to a pointed hand,
a click will cause an action.
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2
DC CDI Systems
3
Objective

• The participants will identify the components and
  their function of a Battery Powered Capacitor
  Discharge Ignition system. This will be
  demonstrated by the participants completing a
  written exam with 80 percent accuracy.

4
DC CDI Systems

• In the world of personal watercraft the ignition
  system design has been exclusively self-powered
  capacitor discharge ignition (AC CDI) systems.
• Today, due to new standards of pollution control,
  the AC CDI system is being replaced by a battery
  powered CDI (DC CDI) system, which is one of the
  most efficient ignition systems available today.

5
DC CDI Systems (contd)

• The DC-CDI ignition system is similar to an AC
  CDI system except that the battery is used as the
  source instead of an AC source (exciter) coil.
• In addition, except for the DC-DC converter, the
  DC-CDI ignition control module is identical to
  the AC CDI unit.

6
DC CDI Systems (contd)

• There is a capacitor in the black box that's
  charged to several hundred volts by a DC to DC
  converter (electronic oscillator) that steps up
  the 12 volts DC from the battery.

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Capacitor Charge
220 volts capacitor charge
Battery Volt (12v).
220 Volts
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DC CDI Systems (contd)

• Then, at the right time, a switch (magnetic)
  that's actuated by a disk on the end of the
  crankshaft puts out a pulse that causes the SCR
  (also in the black box) to dump the capacitor's
  several hundred volts into the coil.

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Ignition Pulse Generator
2 3 Volts
10
Capacitor Discharge
220 volts capacitor discharge
Inducing voltage into the secondary coil
220 volts
11
DC CDI Systems (contd)

• The coil (acting as a transformer) takes the 220
  volt pulse and transforms it to approximately
  30,000 volts for the spark plug.

12
Secondary Current Loop
30 Kv spark
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End
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