Trade secrets don’t need to be enforced much by law. You can create an ad hoc trade secret regime by simply keeping your secret between a few key employees. As it happens, there are some laws that go beyond that to help companies keep the secret, but that only extends something that could happen naturally.
It won’t. Hydrogen has terrible efficiency even when fuel cells are in the pipeline. Putting it in an ICE only makes it worse. It’ll have some racing applications, but that’s it.