The distributor handles several jobs. Its first job is to distribute the high voltage from the coil to the correct cylinder. This is done by the cap and rotor. The coil is connected to the rotor, which spins inside the cap. The rotor spins past a series of contacts, one contact per cylinder. As the tip of the rotor passes each contact, a high-voltage pulse comes from the coil. The pulse arcs across the small gap between the rotor and the contact (they don't actually touch) and then continues down the spark-plug wire to the spark plug on the appropriate cylinder. When you do a tune-up, one of the things you replace on your engine is the cap and rotor -- these eventually wear out because of the arcing. Also, the spark-plug wires eventually wear out and lose some of their electrical insulation. This can be the cause of some very mysterious engine problems.







Older distributors with breaker points have another section in the bottom half of the distributor -- this section does the job of breaking the current to the coil. The ground side of the coil is connected to the breaker points.









A cam in the center of the distributor pushes a lever connected to one of the points. Whenever the cam pushes the lever, it opens the points. This causes the coil to suddenly lose its ground, generating a high-voltage pulse.

The points also control the timing of the spark. They may have a vacuum advance or a centrifugal advance. These mechanisms advance the timing in proportion to engine load or engine speed.

Spark timing is so critical to an engine's performance that most cars don't use points. Instead, they use a sensor that tells the engine control unit (ECU) the exact position of the pistons. The engine computer then controls a transistor that opens and closes the current to the coil.

 

In recent years, you may have heard of cars that need their first tune-up at 100,000 miles. One of the technologies that enables this long maintenance interval is the distributorless ignition.

Instead of one main coil, distributorless ignitions have a coil for each spark plug, located directly on the spark plug itself.



The coil in this type of system works the same way as the larger, centrally-located coils. The engine control unit controls the transistors that break the ground side of the circuit, which generates the spark. This gives the ECU total control over spark timing.

Systems like these have some substantial advantages. First, there is no distributor, which is an item that eventually wears out. Also, there are no high-voltage spark-plug wires, which also wear out. And finally, they allow for more precise control of the spark timing, which can improve efficiency, emissions and increase the overall power of a car.

 

A simple "primary ignition is before the coil, secondary ignition is after the coil" would suffice.

 

Genius.

 

careful, MC, s2ki will hit you hard for plagiarism

 

sshhh

 

let them take it out on me, though

3rd time's a charm, eh?

 

Good work, Rectum!

 

I don't ban people...but I'm more than happy to hunt down any thread jyeung posts in here in the Corner and mock the hell out of him...

 

Who is this 'tard, anyway?