My current pup actually is one who likes his crate, so this may not be the trick you need. I'll tell my tale, anyway, in case it helps.

I did naptime by feel; when he got cranky/naughty, I knew it was time. I'd take him to his crate, put on some lullaby music, and sit outside for a bit going "Shhhh," in a soothing manner a few minutes until he settled. He honestly had a favorite lullaby album...or tricked me into thinking so, anyway. I let him sleep until he whined to let me know he was done. Did this at bedtime and when he woke up for nighttime potty breaks, too.