Patent ID: 7136789

Claim:
A method for generating an acceleration profile for a valve operating cam of an internal combustion engine, the profile satisfying a plurality of constraints, the method comprising: generating a valve acceleration versus cam angle draft curve by specifying a plurality of points of desired valve acceleration versus cam angle and using a curve fitting routine to form the draft acceleration curve interconnecting the plurality of points; developing a set of equations, one for each of the plurality of constraints in terms of parameters of the draft acceleration curve and a plurality of scaling factors, one for each section of the draft curve between roots thereof, and forming a determinant for the set of equations; selecting at least one point on the draft curve as an adjustment point; varying the adjustment point to an adjustment acceleration value that forces the determinant to substantially zero; using the curve fitting routine to generate an adjusted acceleration curve including the adjustment acceleration value; solving the set of equations for values of the scaling factors as a function of parameters of the adjusted acceleration curve; and multiplying values in sections of the draft acceleration curve between roots thereof by resultant values of a corresponding scaling factor to generate and store a constraint satisfied acceleration profile.