A common rail has an accumulation pipe in which high pressure fuel is accumulated, a pipe joint to which a high pressure pipe is connected and an orifice member housed inside the pipe joint. The orifice member is provided with a conduit through which a fuel port formed in the accumulation pipe communicates with the high pressure pipe. The conduit is provided at an end thereof with an orifice. The orifice serves to reduce pressure pulsation generated by fuel injection of an injector so that fuel pressure in the common rail is stable. Since the orifice is formed in the orifice member housed in the pipe joint, the orifice is easily and accurately manufactured at a lower cost, compared to an orifice formed in the accumulation pipe. It is easy to standardize the manufacture of plural models of common rails whose orifice diameters are different.

In an accumulation type fuel injection system for an internal combustion engine, a common rail is formed with an accumulation chamber inside a peripheral wall portion so that a central axis of the accumulation chamber is deviated from that of the common rail, which has a cross section in a complete round shape. Thus, a thick wall portion having thicker wall than other portion of the peripheral wall portion is formed in the peripheral wall portion. A plurality of pipe connecting portions is formed radially inside the thick wall portion. A plurality of pipe connectors is formed separately from the common rail and is connected to the common rail at the pipe connecting portions. As a result, machining of an outer periphery of the common rail is simplified.

A fuel rail assembly for supplying fuel to a plurality of fuel injectors in an engine is provided. This assembly comprises an elongated conduit having a longitudinal fuel passage therein, a fuel inlet pipe fixed to an end or a side of the conduit, and a plurality of branch pipes. The basal end of each branch pipe is adapted to communicate with the fuel passage. The distal end of each branch pipe is provide with a connecting member for connecting to a tip of a fuel injector. The wall of the conduit is provided with holes for receiving the basal ends of the branch pipes. Around each hole an inner collar and an outer collar are integrally formed with the conduit wall, and each branch pipe is fixed to the collars by brazing or welding. The drilling work is performed by a special drilling tool.

A high-pressure fuel accumulator for a common-rail fuel injection system of an internal combustion engine has a tubular main body (1) to which is welded at least one bushing (13) for connecting a high-pressure line (6). To improve the quality and safety of the high-pressure connections, a collar (14) is formed on the end of the bushing (13) facing the main body (1).

A bush incorporated in a common rail is formed with a smallest diameter orifice having a small inner diameter and an adjacent orifice having an inner diameter larger than that of the smallest diameter orifice on an inner peripheral face of the bush. A press-fitted portion, which is press-fitted into an inside-outside communication hole, and a non-press-fitted portion, which has a smaller outer diameter than the press-fitted portion, are formed on an outer peripheral face of the bush. The smallest diameter orifice and the press-fitted portion are deviated from each other in an axial direction of the bush to prevent an overlap in a radial direction of the bush. Thus, even if the bush is tightly press-fitted into the inside-outside communication hole, decrease of the inner diameter of the smallest diameter orifice can be averted.