Assembly for an air circuit of a heat engine

An assembly for an air circuit of a heat engine, comprising:

• a first pipe capable of conveying fluid;
• a second pipe extending between an inlet in the first pipe and an outlet in the first pipe, to form a bypass of a portion of the first pipe, the second pipe comprising a pressure-variation source;
• and
• a switching system for switching fluid into one of either the second pipe or the portion of the first pipe, the switching system having a first configuration allowing the fluid to circulate mainly in said portion of the first pipe, the switching system comprising:
• a holding device exerting a torque configured so as to bring or keep said switching system in the first configuration, and
• at least one first area shutting off in the first configuration at least a portion of the inlet of the second pipe, and one second area shutting off in the first configuration at least a portion of the outlet of the second pipe,
• the switching system being arranged to pass into a second configuration allowing the fluid to circulate mainly in the second pipe when the pressure variation generated in the second pipe by the source exceeds a predefined value, wherein the pressure variation exerts a torque on the at least one of the first and second areas of the switching system, enabling passage into the second configuration, despite a torque exerted by the holding device,
• wherein the torque exerted by the holding device on the switching system decreases when the switching system passes from the first into the second configuration.