Ignition SystemsIgnition Systems

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What is the name of the special tool What is the name of the special tool used to check ignition timing?used to check ignition timing?

• A stroboscopic timing lamp

Name two disadvantages that are Name two disadvantages that are encountered through the use of a encountered through the use of a

mechanical contact breaker mechanical contact breaker distributor.distributor.

• Doesn’t stay accurate for long periods

• Wear out quickly

• Require frequent servicing

• Primary current has to remain low

• Points get ‘bounce’

What is a common symptom of an What is a common symptom of an engine with over retarded ignition?engine with over retarded ignition?

• Engine can run on after switching off.

• Engine can overheat.

• Loss of power

What is a common symptom of an What is a common symptom of an engine with an over advanced engine with an over advanced

ignition?ignition?• Detonation – pinking

• Poor running – lack of power

How does an ignition coil ‘step up’ How does an ignition coil ‘step up’ the voltage from 12V to the required the voltage from 12V to the required voltage to jump a spark plug gap?voltage to jump a spark plug gap?

• Mutual induction.

• Primary winding builds up a magnetic field, then it collapses; this induces a voltage into the secondary windings at a much higher voltage.

What is different about the DIS What is different about the DIS (Distributorless ignition) system (Distributorless ignition) system when compared to other ignition when compared to other ignition

systems?systems?

• A coil is energized and sparks into 2 cylinders at the same time, one spark happens on the power stroke, and the other sparks on the exhaust stroke. It is wasted.

Why would moisture inside of a Why would moisture inside of a distributor cap prevent an engine distributor cap prevent an engine

from running?from running?

• The spark would leak to earth in the cap rather than jump the spark plug.

• The electricity follows the path of least resistance.

What could be a consequence of What could be a consequence of fitting spark plugs to an engine with fitting spark plugs to an engine with

too much reach?too much reach?

• The plug could touch the piston and cause damage.

Why does the ignition timing need Why does the ignition timing need to be advanced with engine speed?to be advanced with engine speed?

• The air fuel mixture has less time to burn so has to be ignited earlier in order to get the point of maximum pressure rise just after TDC.

What is the function of the What is the function of the electronic ignition amplifier used electronic ignition amplifier used

with a Hall Effect distributor?with a Hall Effect distributor?

• It is used to switch the primary circuit current on and off in accordance with the signal received from the hall chip.