JP2006153014A - Fuel supply device equipped with common-rail closed with rail lid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conventionally maintain an advantage of pressure amplitude damping in a functional unit on a rail lid, especially a three-port two-position directional control valve and pressure piping, facilitating an access to the functional unit, in a common-rail fuel supply device for supplying fuel into a fuel injector, in which all functional units as to fuel supply and a fuel continuation guide are incorporated in the rail lid, for a cylinder of an internal combustion engine, having at least one accumulation chamber in a common-rail whose at least one side end surface is closed with the rail lid. <P>SOLUTION: In the fuel supply device, the rail lid (3) is divided into two modules as forms of a seal element (4) and a control unit (5). The seal element (4) is arranged in an airtight connection to the common rail. The control unit (5) is formed so that it can be positioned arbitrarily in the piping between the seal element (4) and the fuel injector (1) to supply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel for a cylinder of an internal combustion engine in which at least one pressure accumulating chamber is provided in a common rail whose end surface is closed by a rail lid, and all functional units relating to fuel supply and fuel continuation guidance are incorporated in the rail lid. The present invention relates to a common rail fuel supply device for supplying fuel to an injector.

  This kind of fuel supply device having the features described in the preamble of claim 1 is known, for example, from US Pat.

  In doing so, it has already been stated that the adoption of the common rail system for large diesel engines is problematic due to the required length of the common rail for all cylinders along the engine axis or a constant accumulated pressure. For that reason already, the common rail is realized with at least two separate rails connected to each other by connecting pipes, each rail being connected to at least two fuel injectors and fed by a high-pressure pump. The provision of common rail injectors to existing engine types is considerably simplified by providing rail covers on both end faces that incorporate all functional units for fuel supply and fuel continuity guidance.

  As described above, all functional units such as the fuel limit valve are present in the rail lid. As a result, the modular assembly is simplified, and external forces resulting from the support and fittings are received by the rail lid formed by the module. The entire rail and common rail are not subjected to the external force, which increases driving safety.

  Fuel is sent from each rail to the above-mentioned rail lid including a plurality of functional units through a flow restriction valve. That is, for example, fuel injection is controlled via a 3-port 2-position switching valve that is directly switched or indirectly operated via an electromagnetic 2-port 2-position switching valve. As is well known, fuel is sent from a three-port two-position switching valve to a joint of a pressure pipe, and is sent to each fuel injector comprising, for example, a normal needle valve.

  As described above, this type of rail cover has at least one 3-port 2-position switching valve (including a 2-port 2-position switching valve for controlling the 3-port 2-position switching valve depending on circumstances), fuel amount limitation. It has a valve, a full pipe joint, a support for the entire common rail to the internal combustion engine, and a fixing device and a sealing device for the tubular rail body.

  The combination of a spring-loaded fuel injector and a 3-port 2-position switching valve located on the rail lid considerably simplifies the addition of common rail injectors to existing engine types. In the functional unit, particularly the 3-port 2-position switching valve, the pressure vibration generated particularly at the end of fuel injection can be prevented by directly attaching the rail lid to the rail.

  However, particularly in the case of a complicated rail cover, there is a possibility that some parts may be worn.

  When such a situation occurs, the entire rail lid must normally be removed or replaced with the entire rail.

When the rail cover is replaced, the high pressure seal surface between the rail and the rail cover is separated, so that a new seal test may be required during service or leakage may occur. Overall, the assembly / disassembly of a conventional rail lid functional unit in a high pressure composite is very laborious.
German Patent Application Publication No. 10157135

  An object of the present invention is to provide a common rail fuel supply apparatus according to the preamble of claim 1 while maintaining the conventional advantage of attenuation of pressure amplitude in a functional unit of a rail cover, particularly a three-port two-position switching valve and a pressure pipe. In order to eliminate the above-described drawbacks of the rail lid, there is an improvement.

  This problem is solved by the features of claim 1 according to the present invention.

  According to the invention, a fuel injector is provided in which the rail lid is arranged in two parts from two modules in the form of a sealing element and a control unit, the sealing element is hermetically connected to the rail and the control unit is supplied with the sealing element The pressure piping between the two components is formed so that it can be arbitrarily positioned, that is, the structural separation between the control unit including all functional units and the sealing element of the rail lid, and the spatial separation of both modules, ie the rail. By positioning the control unit between the fuel injector and the fuel injector, the above-mentioned drawbacks are eliminated by maintaining the positive effects as described above, such as attenuation of the pressure amplitude, particularly at the end of fuel injection, as usual.

  In particular, the spatial separation of the control unit and the sealing element significantly improves the accessibility to the control unit and thus makes it very easy to assemble / disassemble the high-pressure composite.

  Ultimately, the spatial separation between the sealing element and the control unit is 0 to 2000 mm depending on the various mounting positions of the control unit within the frame of the invention, i.e. when the diameter of the pressure pipe is about 7 mm. Thus, the control unit can be directly coupled to the rail sealing element, or can be incorporated in the pressure piping between the rail and the fuel injector, or directly into the fuel injector or in the fuel injector. The best use of space is achieved.

  In any case when replacing the control unit or the functional unit of the unit, it is not necessary to separate the sealing element from the sealing surface of the rail and the risk of leaks is reduced.

  Due to the special spatial separation between the sealing element and the rail lid described above, the advantage of attenuation of the pressure amplitude, especially in the case of an extreme spatial separation of 2000 mm, especially in a 3-port 2-position switching valve and pressure pipe, Is still sufficiently close to the sealing element in a pressure pipe of a predetermined diameter, so that it is kept as usual.

  Further, the best hydraulic harmony of the fuel supply device is possible by the front connection or the rear connection of the hydraulic volume to the pressure pipe, and as a result, deformation of the fuel injection process, mass injection, etc. can be performed.

  This produces various effects such as combustion friendly to the internal combustion engine, improvement of the combustion process, reduction of fuel consumption and reduction of generation of harmful substances.

  In addition, the common rail, pressure piping, sealing elements and control unit and fuel injector can be manufactured separately and best. The manufacturing method is improved, and the completed structure allows the control unit to be disassembled without disassembling the pressure piping in some circumstances.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

  The rail is formed of a tubular part with or without a built-in as is well known, and the end face is sealed with a rail lid 3 in FIGS. 1 to 4 and is arranged approximately at the height of the cylinder head of an internal combustion engine (not shown). ing.

  Each rail is connected to at least one fuel injector 1 which is usually electronically controlled by at least one pressure pipe 2.

  In an advantageous embodiment, one rail is provided for every two cylinders to be fueled. If the number of cylinders is odd, fuel is supplied to only one cylinder by one rail that can be arbitrarily positioned. Depending on the engine type and application, the individual rails connected to each other are filled with 2 to 6 high-pressure pumps.

  As described above, fuel is sent from each rail to the rail lid 3 including a plurality of functional units via the flow restrictor. That is, fuel injection is controlled through a three-port two-position switching valve that is directly switched or indirectly operated by an electromagnetic two-port two-position switching valve. The principle of operation of the individual functional units is well known to those skilled in the art and will not be described here.

  1 and 2, the rail lid 3 according to the invention consists of two separate parts, namely the sealing element 4 and a control unit 5 with all the above-mentioned functional units.

  Each sealing element 4 seals the end face of a rail (not shown) and is therefore firmly connected to the tubular part of the rail with a plurality of bolts 7. Further, a control unit 5 is applied to the seal element 4, and in the present embodiment, the control unit 5 is similarly fixed to the seal element 4 with a bolt 8.

  As described above, the control unit 5 includes at least one three-port two-position switching valve (including a two-port two-position switching valve that controls the three-port two-position switching valve depending on circumstances), a fuel amount limiting valve, and all the valves. On the other hand, the sealing element 4 comprises a support 6 for the entire rail to the internal combustion engine and a fixing device and a sealing device for the tubular rail body of the rail.

  As shown in FIGS. 3 and 4, the control unit 5 can be disposed in either the pressure pipe 2 (FIG. 4) between the seal element 4 and the fuel injector 1 or the fuel injector 1 (FIG. 3).

  The fuel supply apparatus according to the present invention can be applied to all types of large diesel engines, particularly heavy oil fuel internal combustion engines.

1 is a front view of a rail lid according to the present invention arranged on a sealing element of a rail. FIG. FIG. 2 is a side view of the rail lid according to the invention of FIG. 1 showing the interface between two module components. Arrangement structure of rail lid to fuel injector according to the present invention of the rail. The arrangement of the rail lid according to the invention of the rail to the pressure pipe between the sealing element and the fuel injector.

Explanation of symbols

1 Fuel injector, 2 Pressure piping, 3 Rail cover, 4 Sealing element, 5 Control unit

Claims (8)

A common rail type fuel supply device for injecting fuel into a cylinder of an internal combustion engine via a pressure pipe, wherein at least one pressure accumulating chamber is included in a common rail in which at least one end face is closed by a seal element,
The sealing element is formed as a rail lid (3), the rail lid (3) being tightly and airtightly coupled to the two-part structure from the module of the sealing element (4) and the control unit (5) and the sealing element (4) to the common rail. The control unit (5) is arbitrarily positioned with respect to the pressure line (2) between the sealing element (4) and the fuel injector (1) to be supplied, and the control unit (5) A fuel supply device formed so as to incorporate all functional units.   The common rail is composed of a plurality of separate rails connected to each other by a transfer pipe, and each rail has at least one fuel injector, each comprising a rail lid (3) comprising a sealing element (4) and a control unit (5). The fuel supply device according to claim 1, wherein the fuel supply device is connected via   Each rail has a storage volume for supplying two fuel injectors (1), and both ends of the volume have a two-part rail cover (4) and a control unit (5). 3. The fuel supply device according to claim 2, wherein the fuel supply device is closed by 3).   A control unit (5) of the rail lid (3) is arranged in the cylinder head on the pressure line (2) between the sealing element (4) and the fuel injector (1), just before the fuel injector (1). The fuel supply device according to claim 1, wherein the fuel supply device is provided.   The control unit (5) of the rail lid (3) is arranged directly on the sealing element (4) and the pressure pipe (2) exits from the control unit (5) and terminates in the fuel injector (1). Item 4. The fuel supply device according to one of Items 1 to 3.   4. Fuel supply according to claim 1, wherein the control unit (5) is arranged in a pressure line (2) between the sealing element (4) and the fuel injector (1). apparatus.   4. The fuel supply device according to claim 1, wherein the control unit (5) of the rail lid (3) is incorporated in the fuel injector (1).   2. Fuel supply according to claim 1, characterized in that the spatial separation between the sealing element (4) and the control unit (5) is 0 to 2000 mm when the diameter of the pressure pipe (2) is about 7 mm. apparatus.

Images