Intake manifold for an engine and method of controlling intake air flow

An intake manifold for conducting air into an engine, comprising:

• a manifold body, including:
• at least one manifold inlet,
• at least two manifold outlets,
• at least two plenum chambers communicating with the at least one manifold inlet, and
• for each manifold outlet, a set of two runners through which at least one plenum chamber is in communication with at least one outlet, wherein
• each of the sets of two runners includes one runner which has a shorter length than other runner,
• the long runner of a first runner set communicates at a plenum end with a first plenum chamber and at an outlet end with a first manifold outlet, and the long runner of a second runner set communicates at a plenum end with a second plenum chamber and at an outlet end with a second manifold outlet, and
• the short runner of the first runner set communicates at an outlet end with the first manifold outlet, and the short runner of the second runner set communicates at an outlet end with the second manifold outlet;
• a rotary valve disposed in the manifold body between the at least two plenum chambers and between the inlet end of each of the short runners and a wall of the manifold body;
• and
• a rotary valve actuator,
• wherein the rotary valve actuator actuates the rotary valve to rotate between at least three positions, the at least three positions including
• a first position which prevents air flow into the short runners and prevents air flow between the plenum chambers,
• a second position which prevents air flow into the short runners and permits air flow between the plenum chambers, and
• a third position which permits air flow into the short runners and permits air flow between the plenum chambers.

A method of controlling airflow into an engine with an intake manifold, comprising the steps of:

• providing an intake manifold upstream of a plurality of cylinders of the engine, the intake manifold comprising
• a manifold body, including:
• a manifold inlet,
• a plurality of manifold outlets,
• a plurality of plenum chambers which receive air entering the manifold inlet, and
• at least two runners for each manifold outlet, wherein each runner conveys air from at least one plenum chamber to its respective manifold outlet and at least one of the at least two runners has a shorter length than another of the at least two runners;
• and
• a valve disposed in the manifold body which controls air flow from the plenum chambers into the short runners and air flow between plenum chambers;
• determining engine operating conditions;
• actuating the valve, based on the engine operating conditions, to one of at least three intake tract configuration positions, wherein the at least three positions include
• a first position which prevents air flow into the short runners and prevents air flow between the plenum chambers,
• a second position which prevents air flow into the short runners and permits air flow between the plenum chambers, and
• a third position which permits air flow into the short runners and permits air flow between the plenum chambers.