VALVE DRIVE CAM Russian patent published in 2009 - IPC F01L1/08 

FIELD: machine building.

SUBSTANCE: valve gear drive cam comprises valve lift and drop surfaces formed by the curve of 2^nd derivative of valve follower motion along cam turn angle and consisting of positive and negative value sections. Note here that aforesaid sections represent piecewise linear functions of cam turn angle, comprising finite number of portions with preset initial conditions at positive value section start and negative value section end. Note that the 2^nd derivative module value at joints of adjacent portions are maximum, provide constraints for 2^nd and higher order derivatives are satisfied. Note here also that, before positive value section, run-out section is located formed by curve of 3^rd derivative of valve follower stroke with preset lift values, 1^st derivative of follower motion at the start, and values of lift, as well as by 1^st and 2^nd derivatives of valve follower motion at the run-out en. Note here that, provided 3^rd derivative continuity condition is met, 3^rd derivative values at the run-out section end equals zero, while 3^rd derivative values for follower S'" at run-out section are determined from the formula where a is the factor, φ is the current value of cam turn angle, "Ф"_ro is the run-out section length.

EFFECT: reduced dynamic loads of valve gear.

2 dwg