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Difficulty: EasyIgnition System

In an electronic ignition system, several sequential events must take place to ignite the compressed air-fuel mixture in a cylinder. Arrange the following operational steps in chronological order, from initial engine position detection to cylinder combustion. What is the correct sequence of these events?

  1. 1The crankshaft position sensor detects engine rotation and transmits a timing signal to the engine control module.
  2. 2The engine control module switches off current flowing through the ignition coil primary winding.
  3. 3The sudden collapse of the primary magnetic field induces high voltage in the coil secondary winding.
  4. 4The high-voltage surge arcs across the spark plug electrode gap to ignite the air-fuel mixture.

Answer

The correct chronological sequence begins with the crankshaft position sensor transmitting a timing signal, followed by the engine control module interrupting the primary circuit, which causes the coil magnetic field to collapse and induce high secondary voltage, and finishes with the high-voltage pulse jumping the spark plug gap.
The correct sequence follows the fundamental flow of modern electronic ignition: sensing engine position (crankshaft sensor), command switching (module cuts primary current), voltage step-up (collapsing magnetic field induces secondary high voltage), and spark discharge (arc jumps the spark plug electrode gap).

Step-by-Step Solution

1
Identify the initiating trigger event in the electronic ignition system.
The crankshaft position sensor monitors engine rotation and provides the timing baseline signal to the control unit.
Electronic systems cannot determine when to fire without initial position input from the engine rotation sensor.
2
Determine the control response to the trigger signal.
The engine control module opens the primary ignition circuit, interrupting low-voltage battery current.
Breaking the primary circuit is the mechanical or solid-state action required to collapse the coil's magnetic field.
3
Trace the magnetic induction response inside the ignition coil.
The collapsing magnetic field cuts through thousands of fine secondary winding turns, stepping up the potential into tens of thousands of volts.
Mutual induction converts low-voltage primary switching into the high-voltage spike needed for ignition.
4
Identify the delivery and combustion stage.
The high-voltage surge reaches the spark plug and arcs across the gap, igniting the compressed charge.
The electrical arc at the spark plug electrodes is the final operational objective of the ignition circuit.

Key Concept

Electronic Ignition Triggering and High-Voltage Induction Sequence
Estimated Time:45s
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Topics

Ignition System

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