Ignition Coil: Description and Operation

GF15.10-P-2100V Component Description For An Ignition Coil
ENGINE 272.920 in MODEL 203 up to Model Year 8
ENGINE 272.922 in MODEL 211
ENGINE 272.940 in MODEL 203 up to Model Year 8
ENGINE 272.941 in MODEL 203 up to Model Year 8
ENGINE 272.942 in MODEL 171 up to Model Year 8
ENGINE 272.943 in MODEL 211, 219
ENGINE 272.944 in MODEL 211
ENGINE 272.945 in MODEL 251 up to Model Year 8
ENGINE 272.946 in MODEL 221 up to Model Year 8
ENGINE 272.960 in MODEL 203 up to Model Year 8
ENGINE 272.963 in MODEL 171 up to Model Year 8
ENGINE 272.964 in MODEL 211, 219
ENGINE 272.965 in MODEL 221 up to Model Year 8
ENGINE 272.966 in MODEL 230 up to Model Year 8
ENGINE 272.967 in MODEL 164, 251 up to Model Year 8
ENGINE 272.970 in MODEL 203 up to Model Year 8
ENGINE 272.972 in MODEL 211
ENGINE 272.975 in MODEL 221 up to Model Year 8
ENGINE 273.922 in MODEL 221 up to Model Year 8
ENGINE 273.923 in MODEL 164 up to Model Year 8
ENGINE 273.924 in MODEL 221 up to Model Year 8
ENGINE 273.960 in MODEL 211, 219
ENGINE 273.961 in MODEL 216, 221 up to Model Year 8
ENGINE 273.962 in MODEL 211
ENGINE 273.963 in MODEL 164, 251 up to Model Year 8
ENGINE 273.965 in MODEL 230 up to Model Year 8
ENGINE 273.967 in MODEL 209
ENGINE 273.968 in MODEL 221 up to Model Year 8
ENGINE 272.940 in MODEL 209
ENGINE 272.960 in MODEL 209





Shown on ENGINE 272
T1/1...T1/6 Ignition coil cylinders 1 to 6
1 Voltage supply circuit 87 M1
2 Vehicle mass
3 Engine ground
4 Actuation from ME control unit

Location
For each cylinder, a dedicated ignition coil is plugged directly onto the spark plugs.

Task
Supplying adequate ignition energy in all operating conditions for the particular ignition circuit.








Shown on engine 272
T1/1 Cylinder 1 ignition coil
T1/2 Cylinder 2 ignition coil
T1/3 Cylinder 3 ignition coil
T1/4 Cylinder 4 ignition coil
T1/5 Cylinder 5 ignition coil
T1/6 Cylinder 6 ignition coil








Shown on engine 273
T1/1 Cylinder 1 ignition coil
T1/2 Cylinder 2 ignition coil
T1/3 Cylinder 3 ignition coil
T1/4 Cylinder 4 ignition coil
T1/5 Cylinder 5 ignition coil
T1/6 Cylinder 6 ignition coil
T1/7 Cylinder 7 ignition coil
T1/8 Cylinder 8 ignition coil





Design

Shown on engine 272
T1/1...T1/6 Ignition coil cylinders 1 to 6
1 Voltage supply circuit 87 M1
2 Vehicle mass
3 Engine ground
4 Actuation from ME control unit
Arrow: Capacitive tap

The ignition output stages are integrated in the ignition coils.





Internal circuitry of ignition coils with integral output stage
Shown on engine 272

R4 Spark plugs
T1/1...T1/6 Ignition coil cylinders 1 to 6
C1 capacitor
C2 capacitor
D1 Diode
IC Output stage
L1 Primary coil
L2 Secondary coil
R1... 3 Resistor

Function
An output stage is located in each ignition coil for the primary circuit. The ME control unit actuated the ignition coil primary circuit between terminals 2 and 4. The current flow in the primary coil (L1) causes a magnetic field to form. The dwell angle control determines the operating time of the ignition coil primary circuit and thus the magnetic saturation of the ferrous core of the ignition coil.
The primary current flow is interrupted at the moment of ignition timing point. The sudden collapse of the magnetic field generates the ignition voltage in the secondary coil (L2) which is fed directly to the spark plugs.

The voltage supply of the ignition coils is protected at circuit 87 M1

A diode is integrated in each ignition coil for suppressing additional ignition sparks when the output stage is switched off.

Because of the diodes, it is not possible to measure the resistance in the secondary windings. For diagnosis of the ignition coils, the primary current is measured. The capacitive tap is used to connect measuring equipment.