Definition of jake brake in English:

jake brake


  • An engine brake for truck diesel engines that cuts off fuel flow and interrupts the transfer of mechanical energy to the drive mechanism.

    ‘Engine retarders, otherwise known as ‘jake brakes,’ shut down engine cylinders to use engine resistance to slow a truck.’
    • ‘In short, the jake brake turns a power-producing engine into a power-absorbing air compressor, thus slowing the truck.’
    • ‘It shall be unlawful for any vehicle equipped with a compression braking device (jake brakes) to use this device to contain the engine's compression, thus rapidly slowing the engine's revolutions per minute and the vehicle's speed, except in cases of extreme emergency.’
    • ‘I got a call from a guy a while back asking me to look at when it's legal to for semi-trucks to use compression brakes (commonly called the Jake Brake).’
    • ‘Usually seen in trucks, the jake brake shuts off the exhaust valves so that in the exhaust stroke, the burned gasses cannot escape through the exhaust valves. Instead they press against the head of the piston and causes the piston to slow down.’


1980s: from the Jacobs Company, who invented the most common implementation of the technology that the brake is based on.