Theory and Operation of The Jake Brake Engine Brake

To me an exhaust brake is a butterfly in the exhaust pipe. You seem to be referring to a Jake brake which is more effective but more complicated. Here is an old video. Somebody needs to do some better animation but the concepts are true. The engines that use an injector push rod to activate tend to have stronger brakes than those that use another cylinder's exhaust valve. The Cummins ISX has special cam stuff to make

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