Patent ID: 6354265
Filing Date: 2002-03-12
Classification: F01L

Abstract:
A compression release engine brake assembly adapted for use with an internal combustion engine of the type including an engine piston reciprocally mounted within a cylinder for cyclical successive compression and expansion strokes, and an exhaust valve operable to open in a normal exhaust lift event and in a brake lift event; said engine including an exhaust valve actuating mechanism for imparting reciprocal movement to said exhaust valve in response to rotation of a cam shaft including a cam profile defining a base circle portion, a normal lift portion and a brake lift portion rotationally displaced from each other on said cam profile; said exhaust valve actuating mechanism including a cam follower adapted for operative engagement with said cam profile and a valve engagement portion adapted for engagement with said exhaust valve; characterized by said exhaust valve actuating mechanism including:(a) a lost motion device, disposed in series relationship with said exhaust valve and being moveable between a normal lost motion condition and an actuated condition not providing lost motion, in response to movement of an input member between first and second positions, respectively; (b) a biasing spring normally biasing said input member toward said first position; (c) an energy storage spring operable, after being compressed to an energy storage condition, to be able to bias said input member toward said second position in opposition to the force of said biasing spring; (d) a latch mechanism operable to displace said energy storage spring from a non-compressed condition to a compressed condition in response to the movement of said valve actuating mechanism as said cam follower traverses said normal lift portion of said cam profile; and (e) said latch mechanism being operable to release said energy storage spring just before said cam follower traverses said brake lift portion of said cam profile, thereby permitting said energy storage spring to displace from said compressed condition to a relatively non-compressed condition, and thus move said input member to said second position, moving said lost motion device to said actuated condition.