Patent ID: 6055949
Filing Date: 2000-05-02
Classification: F01L

Abstract:
A variable valve actuator (VVA) apparatus for an internal combustion engine having an output shaft and a cylinder valve, comprising:a drive shaft adapted to be driven by the output shaft of the engine for rotation about a drive shaft axis;a drive cam fixed to said drive shaft for rotation therewith;a valve operating (VO) cam arranged to pivot about a pivot axis;a cam follower cooperating with said valve operating cam to move the cylinder valve;a motion transmitting mechanism converting motion of said drive cam about said drive shaft axis into pivotal motion of said valve operating cam,said valve operating cam having a cam surface that extends at least from a cam lift start point to a maximum cam lift point, said cam surface including a first section providing a ramp section, a second section providing a positive acceleration section, and a third section providing a zero acceleration section that includes a situation where acceleration continuously varies within a predetermined infinitesimal window about zero acceleration,said first section extending from said cam lift start point, said second section connecting continuously and smoothly to said first section and extending therefrom toward said maximum cam lift point,said third section connecting continuously and smoothly to said second section and extending therefrom continuously over a predetermined range.