Now you're just being nit-picky. I've heard a lot of people call the exhaust brakes on their diesel trucks "Jake brakes."
Heck it's not even technically correct for the big rigs. It is a JACOBS brake, after the company that pioneered it.
Per the wikipedia page: "Although Jake brake properly refers to the Jacobs brand of engine brakes, the term has become a genericized trademark and is often used to refer to engine brakes or compression release engine brakes in general, especially on large vehicles or heavy equipment."
