Coupling device

A system comprising:

• a fuel injector cup configured to be coupled to a fuel rail and comprising:
• a first part having a top end and a bottom end, the top end comprising a fuel inlet of the injector cup, the bottom end comprising a recess, and
• a second part received in the recess of the first part, and when received in the first part, lining at least an entire wall of the recess and fitting flush into the recess,
• wherein the second part comprises a second material with a second porosity and the first part comprises a first material with a first porosity,
• wherein the first porosity defines void spaces having a size of about 80-120 μm and the second porosity is lower than the first porosity and defines void spaces having a size of about 5-10 μm and
• wherein the lower second porosity of the second part defines a smooth surface of the second part, and
• a fuel injector comprising a fuel inlet portion and a sealing portion, wherein the sealing portion engages the smooth surface of the second part of the fuel injector cup to provide a secure sealing between the fuel injector and the second part to hydraulically couple the fuel inlet portion of the fuel injector to the fuel injector cup.

A method for assembling a coupling device for hydraulically and mechanically coupling a fuel injector to a fuel rail of a combustion engine, the method comprising:

• providing a first part having a top end and a bottom end, the top end comprising a fuel inlet of the injector cup, the bottom end having a recess, the first part further comprising two first bores for connecting a connector plate of the fuel injector to the fuel injector cup,
• providing a second part including (a) a body portion configured to be received in the recess of the bottom end of the first part, and (b) a flange portion extending outwardly from the second part body and defining a planar bottom surface configured for flush engagement with a planar surface of a connector plate for securing the fuel injector to the coupling device, wherein two second bores are formed in the planar bottom surface, the two second bores aligning with the two first bores of the first part when the second part is received in the recess of the first part, and
• inserting the second part in the recess of the first part so that the second part lines at least walls of the recess,
• wherein a porosity of the second part is lower than a porosity of the first part.

A fuel injector cup for hydraulically and mechanically coupling a fuel injector to a fuel rail of a combustion engine, the fuel injector cup comprising:

• a first part having a top end and a bottom end, the top end comprising a fuel inlet of the injector cup, the bottom end comprising a recess, and
• a second part received in and lining at least walls of the recess,
• the second part configured to receive the fuel inlet portion of the fuel injector,
• wherein the first part comprises cast stainless steel,
• the second part comprises a machined, stamped, or deep-drawn stainless steel having a tubular shape with a flange, and a press-fit or shrink-fit connection and/or a brazed connection between the first and second parts,
• wherein the stainless steel of the second part has a second porosity and the cast stainless steel first part comprises a first material with a first porosity, and
• the first porosity is higher than the second porosity, wherein the first porosity defines void spaces having a size of about 80-120 μm and the second porosity defines void spaces having a size of about 5-10 μm, wherein the lower second porosity of the stainless steel second part defines a smooth surface of the second part for providing a secure sealing when engaged with a respective surface of the fuel injector received in the second part.