Inlet manifold with ringed air tubes for an internal combustion engine

An inlet manifold for an internal combustion engine;

• said inlet manifold comprising:
• an envelope, delimiting a plenum chamber for supplying air to an engine, and equipped with at least one flange for attaching said plenum chamber to at least one cylinder head of the engine, said at least one flange having at least one supply opening for supplying at least one cylinder of the engine, said at least one supply opening opening, on the one hand, into said envelope and, on the other hand, into a face for attaching said at least one flange to said at least one cylinder head;
• at least one curved, one-piece, air-induction tube corresponding in number to said at least one cylinder of the engine, and mounted in said envelope so that each said at least one curved air-induction tube supplies a corresponding said at least one cylinder with air via an inlet in said plenum chamber and transmits air to a corresponding one of said at least one supply opening in said at least one flange via an outlet connected by leaktight connection means for connecting to said at least one supply opening, wherein each said at least one curved air-induction tube comprises a tube member with a ringed external face and a smooth internal face delimiting a central passage with a cross section which is substantially constant in shape and surface area, wherein said at least one curved air-induction tube has great transverse suppleness or flexibility but low axial suppleness or flexibility;
• and
• wherein said ringed external face of each said at least one curved air-induction tube comprises a cylindrical surface of revolution with a wavy generatrix before the tube member is bent into a desired shape.

An inlet manifold for an internal combustion engine;

• said inlet manifold comprising:
• an envelope, delimiting a plenum chamber for supplying air to an engine, and equipped with at least one flange for attaching said plenum chamber to at least one cylinder head of the engine, said at least one flange having at least one supply opening for supplying at least one cylinder of the engine, said at least one supply opening opening, on the one hand, into said envelope and, on the other hand, into a face for attaching said at least one flange to said at least one cylinder head;
• at least one curved, one-piece, air-induction tube corresponding in number to said at least one cylinder of the engine, and mounted in said envelope so that each said at least one curved air-induction tube supplies a corresponding said at least one cylinder with air via an inlet in said plenum chamber and transmits air to a corresponding one of said at least one supply opening in said at least one flange via an outlet connected by leaktight connection means for connecting to said at least one supply opening, wherein each said at least one curved air-induction tube comprises a tube member with a ringed external face and a smooth internal face delimiting a central passage with a cross section which is substantially constant in shape and surface area, wherein said at least one curved air-induction tube has great transverse suppleness or flexibility but low axial suppleness or flexibility;
• wherein said envelope comprises two molded half shells, of complementary shapes corresponding to a shape of said envelope said half shells having attachment flanges on peripheral edges in a parting plane, said half shells being closed and fixed together at said attachment flanges, and wherein each said at least one curved, one-piece, air-induction tube is fixed to said half shells by at least one tube end;
• and
• wherein said at least one tube end of each said at least one curved, one-piece, air-induction tube is fixed to a half shell using a sleeve which is partly force-fitted into a corresponding said at least one tube end of said at least one curved, one-piece, air-induction tube and held on said half shell by a sleeve part external to said at least one curved, one-piece, air-induction tube.