Catalyzes the reversible dehydration of L-carnitinyl-CoA to crotonobetainyl-CoA (PubMed:11551212). Can also hydrate crotonyl-CoA to hydroxybutyryl-CoA (PubMed:11551212). (R)-carnitinyl-CoA = crotonobetainyl-CoA + H2O 3-hydroxybutanoyl-CoA = (2E)-butenoyl-CoA + H2O Amine and polyamine metabolism; carnitine metabolism. Homotrimer. Belongs to the enoyl-CoA hydratase/isomerase family. Extended N-terminus. Extended N-terminus.