Automotive hardening?

[mr_guy99493]

Hi,
I'm thinking of building a PLC-type module for automotive use.
Lots of 12V IO, relay drivers, CAN bus, bluetooth.

I feel like the automotive use-case may require extra hardening against various effects like noise on the bus due to injectors/sparkplugs etc -> filtering, zeners, surge arrestors?

Questions:
Am I right that there are special considerations required for automotive circuits?
What sort of considerations?
Any good references about how to adapt to those problems?
Reference designs that implement them?

Thanks

[AndyC_772]

Yes, you're absolutely right, the automotive environment does require protection for exactly the reasons you suggest.

Here's an app note from TI that describes a number of industry standard tests that are carried out on automotive products. You may find it a useful starting point:

https://www.ti.com/lit/ug/tiduc41/tiduc41.pdf

[coromonadalix]

dont forget humidity and vibrations

[MisterHeadache]

Most automotive OEM's write their own EMC/RFI/ESD requirements and restrict who has access to those specifications.  For example, General Motors has their standard GMW3097 (general specification for electrical/electronic components and subsystems, electromagnetic compatability).  It's 82 pages but also references many other ISO and other industry standards for details.  Those are not free, they each must be purchased.

So getting actual specs will require investment on your part.  If your project is just a hobby project, then you can likely find basic enough info from the app notes like AndyC_772 mentioned.

Do you need third party lab certification testing for your project?  If so, then that really gets costly. A new sensor EMC plan for example typically costs betwen $30k to $100k to be performed by certified US labs, depending on the quantity of tests and parts that the OEM requires be tested.