Patent ID: 8499740

Claim:
An engine braking system for vehicles, comprising: a rocker shaft having a lubricating oil passage and a braking oil passage therein in an axial direction thereof, wherein oil for lubricating engine parts on operating an engine flows through the lubricating oil passage and oil for operating an engine braking flows through the braking oil passage; a valve unit selectively supplying part of the oil supplied to the lubricating oil passage, into the braking oil passage; at least one exhaust rocker arm, into which the rocker shaft is inserted and pivotal about the rocker shaft to selectively press an exhaust valve, wherein the at least one exhaust rocker arm has, therein, a first connection passage communicating with the braking oil passage and a first recess formed in the at least one exhaust rocker arm; a stopper fixed above the first recess of the at least one exhaust rocker arm with a predetermined gap therebetween; and an actuator housed in the first recess and including a pressing piston, wherein the pressing piston moves to contact the stopper by hydraulic pressure of the oil supplied from the braking oil passage into the first recess and thus presses one side of the at least one exhaust rocker arm in a downward direction; wherein the predetermined gap is adjusted by moving the stopper; and wherein the stopper is mounted to at least one holder provided separately from the at least one exhaust rocker arm so as to be disposed apart from an upper end face of the pressing piston with the predetermined gap.