Braking device for a valve controlled internal combustion engine

A braking device for a valve-controlled, four-cycle, internal combustion engine for motor vehicles, wherein the internal combustion engine includes cylinders having exhaust and intake valves and wherein the exhaust and intake valves are opened by single cam lobes mounted on a cam shaft, which engage valve operators so that during power operation, the exhaust and intake valves are each opened once during each set of four cycles, the braking device comprising:

• a bore extending through the cam shaft;
• an operating shaft received within said bore for reciprocation therein, the operating shaft having a reduced diameter portion and an enlarged diameter portion thereon;
• a hole through the cam shaft positioned 160.degree. to 200.degree. ahead of the lobe on the cam shaft in the direction of rotation of the cam shaft;
• a supplemental cam positioned within the hole and being in engagement with the operating shaft that is within the cam shaft;
• means for aligning the reduced diameter portion of the operating shaft with the supplemental cam during power operating of the engine;
• means for moving the operating shaft in the cam shaft to a position where the enlarged diameter portion engages the supplemental cam to project the supplemental cam a sufficient distance beyond the cam shaft to engage the valve operator to open the exhaust valve during braking operation of the engine, whereby air compressed within the cylinder is released through the exhaust valve during what would have been the power cycle of the engine.