Engine braking system for internal combustion engine includes outlet valve with valve stem, also exhaust cam with first cam projection opening outlet valve during exhaust phase of engine

摘要

A valve lifter (15) has a valve stem (5) arranged in a movement transmitting relationship between the exhaust cam (10) and the valve stem. The valve lifter includes a cam follower surface (21), working with the cam. A two-position valve (49) has a first setting, which facilitates the discharge of the hydraulic fluid from the valve lifter, and a second setting, which facilitates, a supply of fluid to the valve lifter. The valve lifter has a first position for the normal engine operation in which the cam follower surface is spaced from the base circle (13) of the exhaust cam, in order to determine in between a predetermined gap, which is large enough, to facilitate the passage of the second cam projection (12) across the cam follower surface without the opening of the exhaust valve (4), during the compression phase. The valve lifter has a second position for the engine brake drive, in which the cam follower surface is spaced slightly distanced from the base circle of the exhaust cam, to facilitate by the cam projection the opening of the exhaust valve during the compression phase. The valve lifter takes up the first setting, as a response to the discharge of the hydraulic fluid from this and the lifter takes up the second setting as a response to the supply of hydraulic fluid to this.