Multifunctional assembly for fuel system, tank with such an assembly and method of making the system

Multifunctional assembly (1) comprising two elements (1; 2) of a fuel system, intended to be fixed on the envelope of a fuel tank, these elements performing distinct functions within the fuel system, one of the elements being able to be constituted by a canister and the other element by a device ensuring at least one of the ROV, ISR, SLV, SPD, ORVR or OBD functions, the multifunctional assembly being characterized by the fact that the two elements (1; 2) comprise respective first (3) and second (4) connection parts allowing their assembly independently of the fuel tank envelope and without integration of one element into the other.