Hi,

For automotive application, your have to be compliant with the used standards. It will give you the voltage range, the profile of the cranking phase, the value of load dump and so on.
We've designed a power supply for an embedded Electronic Control Unit for a truck application in the past.
There was a switched regulator LM2575 allowing to supply the ECU with voltages up to 40V. There was also many protections to be compliant with the standards.

Regards
Stephane