the purpose of a jake brake is compression release.
what is the purpose of a jake brake?
compression release
compression release engine brake





























a compression release engine brake, frequently called a jacobs brake or jake brake, is an engine braking mechanism installed on some diesel engines. when activated, it opens exhaust valves in the cylinders after the compression stroke, releasing the compressed gas trapped in the cylinders, and slowing the vehicle.





























the term "jake brake", which properly refers to the jacobs brand of engine brakes, 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.





























section::::function.
compression release engine brake
a “jake brake” is an engine compression release brake used especially for steep hill downgrades. the jake brake opens the exhaust valves when the piston is near top dead center (where ignition normally occurs). on the upstroke, the piston compresses the air in the cylinder to 1/15th its original volume, which creates drag on the engine. the jacobs engine brake then releases the compressed air and the energy stored in it before it can push back on the piston during the down stroke. the jake brake turns a power producing engine into a power absorbing air compressor and in turn, causes the truck to slow down.
jacobs vehicle systems