We often do that in our truck, so we can have a hot lunch at a Rest Stop. Works Very Well. We bought ours at a truck stop.
Before the advent of such handy items as crock pots, there was a different way of preparing a meal at the end of a trip. One person had his method down to a real science. He would wrap whatever he needed to be cooked in aluminum foil, at the proper time place each item on the manifold of his car. The article I read did not mention if food cooked by this method was tender or tough. My guess is, it was not the former. Don