Intake system for an internal combustion engine

An intake system for a multicylinder internal combustion engine, comprising:

• a manifold having a plurality of inlet runners for conducting charge air into the cylinders of an engine;
• at least one secondary throttle valve situated within at least one of said inlet runners;
• at least one secondary throttle valve position sensor for sensing the position of said at least one secondary throttle valve;
• an actuator for positioning said at least one secondary throttle valve;
• an engine speed sensor for sensing engine speed;
• and
• a controller for operating said actuator so as to move said secondary throttle valve between a first, relatively restricting position, to a second, relatively unrestricting position, with said controller receiving sensed values from said engine speed sensor which is representative of engine speeds and from said at least one secondary throttle valve position sensor which is representative of position of said at least one secondary throttle valve, calculating a rate of change of engine speed over time based on said sensed values, determining an appropriate position for said secondary throttle valve, determining an optimum transition point between said first and said second positions, calculating an engine speed which is representative of an engine speed point before said transition point and thereafter initiating operation of said actuator at said engine speed point such that the engine smoothly transitions between engine operating conditions.

A method for controlling the operation of secondary throttle valves in an engine, the engine having a manifold having a plurality of inlet runners for conducting charge air into the cylinders of the engine, at least one secondary throttle valve situated within at least one of the inlet runners, and an actuator for positioning the secondary throttle valve, with said method comprising the steps of:

• sensing at least one operating parameter of said engine;
• determining an appropriate position for said secondary throttle valve;
• predicting an optimum transition point at which said throttle valve transitions to said appropriate position;
• and,
• initiating operation of said actuator at a point before said transition point so as to move the secondary throttle valve between a first, relatively restricting position, and a second, relatively unrestricting position such that the engine smoothly transitions between a first operating condition and a second operating condition.