Vacuum management system for engine with variable valve lift

In an internal combustion engine having a primary throttle means including variable lift mean for intake valves of said engine, an intake manifold for conveying air to combustion cylinders through the intake valves, a pressure sensor disposed in the intake manifold, a secondary throttle means disposed at an inlet to the intake manifold, an exhaust recirculation valve connected to the intake manifold, a fuel emissions canister purge valve connected to said intake manifold, and a programmable engine control module connected to the variable lift means and to the pressure sensor and to the secondary throttle means for controlling the variable lift means and the secondary throttle means, a method for providing a desired flow of air through the intake valves at a desired pressure in the manifold, comprising the steps of:

• a) first determining a plurality of engine operating conditions, including load demand by an operator;
• b) second determining an optimum lift for said intake valves, an optimum manifold pressure, a position of said secondary throttle means, a desired position of said exhaust gas recirculation valve, and a desired position of said canister purge valve, responsive to said determined engine operating conditions, to yield said optimum manifold pressure;
• c) setting said intake valves at said optimum lift and said secondary throttle means at said determined position to provide the desired flow of air through the intake valves at the desired pressure in the manifold;
• d) setting said exhaust gas recirculation valve at said desired position;
• and
• e) setting said canister purge valve at said desired position.