Theory of Operation
As the driver releases the accelerator in order to slow down, the wheels of the vehicle continue to turn the drivetrain. This forces the pistons up and down inside the engine, compressing the air inside the cylinders. The Engine Compression Brake will open the exhaust valve just before the piston reaches the top of the compression stroke, and in doing so, absorbs and releases the pent up energy.
By turning the energy producing ISC into an energy absorbing air compressor, the engine becomes a highly effective brake on the drivetrain which slows the vehicle considerably.