Linkage mechanism for supercharger system

In an engine of the type including an expansible combustion chamber, a supercharger having an inlet and an outlet, first and second air flow paths connected in parallel, the first path to deliver unsupercharged air to the chamber, the second path to deliver air to the supercharger inlet and from the supercharger outlet to the chamber, and power control means having means selectively moveable between minimum and maximum engine power positions, the improvement comprising:

• valve means including a valving member and means responsive to pressure, said valving member moveable between a first position respectively allowing and substantially blocking air flow to the combustion chamber via the first and second paths and a second position respectively allowing and blocking air flow to the combustion chamber via said second and first paths, and said pressure responsive means for biasing said valving member toward said first position in response to predetermined pressure differences between portions of said first and second paths;
• and
• a linkage means including means for resiliently moving said valving member from said first position to said second position in response to movement of said selectively movable means from said minimum to said maximum position.

In a system adapted to supply combustion air to an inlet of an expansible combustion chamber of an engine having a supercharger to boost the pressure of the air;

• the system including a manifold assembly defining first and second air flow paths for respectively directing unboosted and boosted air to the chamber inlet, the first path having an unboosted air inlet and an outlet communicating with the chamber inlet, the second path having an air inlet and outlet communicating respectively with upstream and downstream portions of said first path, and the second path inlet and outlet adapted to be interposed by the supercharger;
• the improvement comprising:
• a butterfly valving member disposed in the first path between the second path inlet and outlet and moveable between open and closed positions respectively allowing and blocking air flow thereacross, said butterfly valving member having unequal surface areas with respect to its pivotal axis to assist opening movement of said valving member.