Comparison of ISO 7637 transient waveforms to real world automotive transient phenomena

Modern automotive electronic systems must operate as designed while exposed to transient voltages produced on the vehicle's power distribution system via switched inductive loads. ISO 7637-2 presents a number of test pulses that are presumed to simulate the actual transients produced in the vehicle. This paper compares three of those pulses (pulses 1, 3a and 3b) to actual transient events which are the result of contact arcing during deactivation of an inductive load. The paper demonstrates that the pulses 1, 3a, and 3b are overly simplistic representations of a more complex waveform. This over simplification may impact accurate assessment of system robustness in the presence of actual transient events.