Monolithic Fuel Rail Structure and Method of Manufacture

A fuel rail assembly that comprises a monolithic fuel rail structure and a fuel injector supported on the fuel rail structure, wherein

• the fuel injector comprises:
• an injector housing;
• a fuel inlet end;
• a fuel outlet end opposed to the fuel inlet end;
• and
• a seal disposed on an outer surface of the injector housing,
• the monolithic fuel rail structure comprises:
• a log;
• an injector cup that protrudes integrally from an outer surface of the log;
• and
• a fuel passage,
• the log including:
• a log first end;
• a log second end that is opposed to the log first end;
• and
• a log inner surface that defines a main fuel channel that is concentric with a longitudinal axis of the log, the longitudinal axis of the log extending between the log first end and the log second end, and
• the injector cup including:
• a sidewall, an inner surface of the sidewall defining a bore;
• a proximal end that closes one end of the sidewall;
• and
• a distal end that is opposite the proximal end, the distal end being open, a centerline of the sidewall extending through the proximal end and the distal end,
• and wherein
• the bore includes an open end that coincides with the distal end,
• the bore includes a blind end disposed between the open end and the injector cup proximal end, and
• the fuel passage provides fluid communication between the bore and the main fuel channel, the fuel passage corresponding to a portion of a hole that extends through the injector cup on each of opposed sides of the injector cup.

A method of manufacturing a monolithic fuel rail structure, the method comprising the following method steps:

• providing a metal billet;
• heating the metal billet to a predetermined temperature that is less than the melting temperature of the metal;
• forging the heated metal billet to provide a monolithic fuel rail structure, the fuel rail structure including a log and an injector cup that protrudes integrally from an outer surface of the log, the injector cup including
• a cylindrical sidewall, an inner surface of the sidewall defining a bore,
• a proximal end that closes one end of the sidewall, and
• a distal end that is opposite the proximal end, the distal end being open;
• machining a main fuel channel in the log;
• machining a bore in the injector cup;
• machining a fuel passage in the fuel rail structure that provides fluid communication between the main fuel passage and the bore, the fuel passage corresponding to a portion of a hole that extends through the injector cup on each of opposed sides of the injector cup.

A monolithic fuel rail structure that is configured to receive and support a fuel injector relative to a cylinder of an engine, the monolithic fuel rail structure comprising:

• a log having an inner surface that defines a main fuel channel;
• an injector cup that protrudes integrally from an outer surface of the log, an inner surface of the injector cup define a bore that opens at one end of the injector cup;
• and
• a fuel passage that provides fluid communication between the bore and the main fuel channel,
• wherein
• the fuel passage corresponds to a portion of a hole that extends through the injector cup on each of opposed sides of the injector cup.