HEI Ignition Coils
The left over energy in coil is stored in current. Inductors store current, similar to capacitor storing voltage. Shown below is a picture of a COP coil making 3 sparks. The first takes about 1.6 ms to charge, discharge 0.25 ms, the following 2 charge 0.85 ms. Notice where the current starts for second and third charged. On the last spark notice the slow voltage decay for final discharge 2.0 ms, but trace cut short, saving pic. Upper trace coil current, peak about 9A, lower trace coil primary voltage, peak about 400V limited by IGBT protection, coil ratio of about 90, steps that up to plug.
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Test setup with uC showing values for multi-spark.
The left over energy in coil is stored in current. Inductors store current, similar to capacitor storing voltage. Shown below is a picture of a COP coil making 3 sparks. The first takes about 1.6 ms to charge, discharge 0.25 ms, the following 2 charge 0.85 ms. Notice where the current starts for second and third charged. On the last spark notice the slow voltage decay for final discharge 2.0 ms, but trace cut short, saving pic. Upper trace coil current, peak about 9A, lower trace coil primary voltage, peak about 400V limited by IGBT protection, coil ratio of about 90, steps that up to plug.
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Test setup with uC showing values for multi-spark.
