A Jake Brake, also known as a Jacobs brake, is a type of compression release engine brake that helps truck drivers slow down their truck without wearing out the service brakes
. It is an engine braking mechanism installed on some diesel engines. When activated, it opens exhaust valves to the cylinders, right before the compression stroke ends, releasing the compressed gas trapped in the cylinders, and slowing the vehicle
. The Jake Brake got its name from Jacobs Vehicle System Inc., the company that created it
. The terms Jacobs brake and Jake Brake properly refer to compression brakes manufactured by Jacobs, though the terms have now become generic trademarks, and are often used to refer to compression brakes in general, especially on large vehicles and heavy equipment
. The use of Jake Brakes is prohibited in some areas due to the loud noise they produce
