When an eight-cylinder engine is running at 3,000 rpm, its ignition coil must do remarkable things. If a single coil is used, its magnetic field must be able to build up and collapse 200 times in 1 second.

Question

Quizplus · Accepted Answer

In an eight-cylinder engine, each of the eight cylinders requires a spark from the ignition coil for every two revolutions of the engine. At 3,000 revolutions per minute (rpm), or 50 revolutions per second, this means the coil must fire 4 times per revolution per cylinder (since it's a four-stroke engine, requiring a spark only on the power stroke, which occurs every other revolution for each cylinder). Therefore, 8 cylinders x 25 sparks (half of 50 revolutions for a four-stroke cycle) equals 200 sparks per second.

When an Eight-Cylinder Engine Is Running at 3,000 Rpm, Its