Auto electricity

I. PRESENTATION OF THE SYSTEM:

In the following diagram, color the low voltage circuit (12 V) in green and the high voltage circuit (2 kV to 20 kV) in red.

II. SYSTEM ANALYSIS:

III. CONSTITUTION OF THE SYSTEM:

The ignition coil:

1-1. Principle of operation:

The operating principle is based on the laws of electromagnetism.

1-2. Creation of a magnetic field:

When a coil wound around a soft iron core is traversed by a current of intensity I, it creates a magnetic field as for a magnet.

The magnetic field thus obtained is called MAGNETIC FLUX and it is directly proportional to the INTENSITY I passing through this coil.
The variation of the intensity in the primary winding is obtained by the intermittent opening of the breaker which is controlled by the cam of the igniter.

1-3. Creation of an induced current:

If a second winding isolated from the first is wound around the same core, we see that each time there is a variation in the magnetic flux, there is creation of an induced electric current in the secondary winding.

1-4. Creation of high voltage:

The voltage of the secondary current will be all the greater if:
– The variation in magnetic flux will be large and rapid.
– The ratio between the numbers of turns of the windings (N1 / N2) will be great.

V. THE DIFFERENT ADVANCES ON IGNITION:
1. Centrifugal feed:

2. The vacuum advance:
The purpose of the vacuum advance is to compensate for the variation in the filling of the cylinder as a function of the position of the throttle valve.

THE DISADVANTAGES OF CLASSIC IGNITION:
– Deterioration of contacts when the electric arc occurs.
– Obligations to control the spacing of the breakers
– Wear of moving parts.

VI. OTHER IGNITION SYSTEMS:

1. Solid state ignition with switches :