Apart from EMC testing such as transient testing of vehicle battery supply lines and RF conducted and radiated immunity, battery supply simulation for electrical loads connected to the 12V, 24V or future 42V supply is becoming more and more important. Vehicle manufacturers specifically do a large number of such tests exceeding by far what ISO 7637 requires. Pulse 4 (motor start-up pulse) and pulse 2b (motor shut down pulse, introduced in ISO 7637:2003) are suggested.
The field of battery supply simulations is not a fundamental question of EMC. It also has something to do with electrical load functions, failure criteria and acceptance criteria and therefore is also mixed up with typical EMC test procedures. In various manufacturers' specification there is no difference between EMC testing and battery supply simulations.
Looking at vehicle manufacturers specifications there are a large number of additional tests like micro-interruptions, dips and drops, all with considerable fast rise and fall times, voltage variations, over voltage, under voltage and reverse voltage tests. With each edition of manufacturers specifications it is possible that you could find some modified or new test requirements.
Looking at such extensive requirements, it is obvious that manufacturer's consider battery supply simulation to be at least as important as transient testing to ensure proper, save and reliable function of all parts and systems in a vehicle. This paper gives an overview of such requirements and makes cross references between international standards and manufacturer requirements.