FI117984B - Pressure storage arrangement for fuel supply system for internal combustion engine - Google Patents

Description

117984

COMPRESSIONAL OIL SYSTEM - BRÄNSLE TILLFÖRSELSYSTEMS TRYCKFÖRRÄDAR-RANGEMANG FÖR FÖRBRÄNNINGSMOTOR

The invention relates to a pressure storage arrangement for an internal combustion engine fuel supply system according to the preamble of claim 1.

In the case of piston engine fuel systems, the so-called "propellant" has been widely applied. common rail systems, in which fuel is fed to a high-pressure common-pressure store and then metered into each engine cylinder by controlling the operation of the fuel injection nozzle 10.

The common rail must be built to withstand very high pressures, typically in the order of> 100 MPa. Pressure reservoirs are typically built like cylinders with a cylindrical structure. Such a structure results in very thick wall thicknesses and thus, e.g. the space requirement is relatively high relative to the volume of the pressure accumulator itself.

The state of the art is represented by a solution using common rail technology, as disclosed in the applicant's prior patent US 6240901. Here, fuel is fed from the fuel tank via a high pressure pump to a pressure reservoir, from where it is further fed by injectors to the engine cylinders. The fuel pressure storage depot 20 comprises at least two separate pressure accumulator units, each connected to · · 1 at least two injectors and provided with its own high pressure pump. • · · .1 ·: To balance the pressure of the substance, the pressure accumulators are continuously connected, and one of the • accumulators in the system is provided with a valve through which the pressure state of the accumulator in question is: connectable to the fuel tank. Such a solution requires relatively large space around the engine. The pressure accumulators are shown in * · · .1 · in the publication. 117984 cylindrical, thick-walled chambers, which, as mentioned above, lead to very thick wall thicknesses and, thus, e.g. the space requirement is relatively high.

It is an object of the invention to provide a pressure storage arrangement for a combustion engine fuel supply system 5 which minimizes prior art problems. In particular, it is an object of the invention to provide a pressure storage arrangement for a fuel supply system for an internal combustion engine which minimizes space requirements in the vicinity of the engine.

The objects of the invention are mainly achieved in the manner detailed in claims 1 and 10.

According to the invention, the pressure storage arrangement of the internal combustion engine fuel supply system comprises at least one pressure reservoir comprising a fuel inlet and outlet, and wherein the pressure reservoir comprises at least two separate chambers in fluid communication with each other and bounded at least partially by a common partition.

• · * · · ”* The pressure reservoir comprises a main chamber | in fluid communication with one another And «and at least one auxiliary chamber of which the main chamber is in fluid communication with the outlet. : '.'. I and at least one auxiliary chamber is in fluid communication with the fuel inlet.

Preferably, the pressure reservoir is an elongated body member in which the chambers are formed from spaces along the longitudinal axis of the pressure reservoir. Further, the pressure reservoir • * · * · · comprises fuel inlet and outlet terminals located at opposite ends of the pressure reservoir. There is a first end piece and a ··· ·· ”second end piece for the body part. In the body, the pressure storage chambers comprise • · * »*; * 25 spaces extending from one end of the body to its other end w» • · · * · *., And each end piece comprising a connection to each of said spaces. '·· ** at least one flow channel. Such a flow channel is further connected to said inlet and outlet connections.

3, 117984

The body of the pressure reservoir is substantially circular in cross-section, and the spaces consist of spaces of substantially circular cross-section, such as bores, in the longitudinal axis of the body. The spaces are disposed in a cross-section of the body member substantially symmetrically with respect to its central axis.

5 The total volume of the pressure reservoir shall be at least 30 times the volume of fuel injected from one injection nozzle at one engine stroke. In this way, the partial volumes can be formed into an inexpensive unit which maintains the pressure at a sufficient level, but without the size of the pressure reservoir being unnecessarily large.

Preferably, there is one pressure reservoir per cylinder of the engine. In addition, each pressure reservoir is fitted at least partially within the cylinder-blade cover of each cylinder of the engine.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 15 schematically illustrates a pressure storage arrangement for an internal combustion engine fuel supply system, Fig. 2 schematically illustrates a pressure storage arrangement according to the invention. in a preferred embodiment applied to the fuel supply system, Figure 3 shows a detail of the fuel supply system of Figure 2, and Figure 4 shows a section 3-3 of Figure 3.

• · • * *

Fig. 1 schematically shows a part of a piston engine 2 and a related fuel supply system i *; ** The piston engine is of a type known per se, as well as a fuel supply system. The piston engine • * · • * *; · * comprises a plurality of cylinders 4 fitted to its body 3, each having its own • ·: .V cylinder head 7. Each cylinder has at least one fuel injection nozzle. 5. The fuel supply system is so called. a common rail system, i.e. comprising at least one fuel pressure reservoir 6. In the solution of Figure 1, each cylinder comprises its own pressure reservoir. In this way, the pressure reservoir is very close to the fuel injection nozzle 5 itself, whereby the fuel pressure losses during injection are sufficiently small.

The pressure reservoir is provided in accordance with the invention so as to consist of at least two separate chambers 6.1,6.2 which are in fluid communication with each other. In addition, the chambers are at least partially bounded by a common partition 6.3. The structure of the pressure reservoir itself will be explained in more detail later.

Fig. 2 schematically shows another embodiment of the solution according to the invention. It also shows a portion of a piston engine 2, and a fuel supply system 1 associated therewith 10. The piston engine is of a type known per se. The piston engine comprises a plurality of cylinders 4 fitted to its body 3, each having its own cylinder head 7. Each cylinder has at least one fuel injection nozzle 5. In this embodiment, each cylinder 4 has its own separate fuel pressure reservoir 6. The system is very compact and inexpensive the pressure reservoir for each of the cylinders 4 is at least partially surrounded by a cylinder 7 cover. In this case, the fuel pressure reservoirs 6 take up less space and, on the other hand, the cylinder head design can be utilized to protect the pressure reservoir. Thus, for example, in the first stage, possible fuel leakage may be limited to the pressure reservoir space in the cylinder head 7 and thus more easily detected. In addition, the cylinder head carries heat to the pressure reservoir, which heats up the fuel. This solution also provides a pressure reservoir closer to the fuel injection nozzle 5, which reduces the flow of pressure between the pressure reservoir 6 and the injection nozzle 5.

In this case, the pressure reservoirs 6 are in fluid communication with each other and also with the other fuel supply system 1, mainly through the external piping 8 of the cylinder head. The piping 8 is connected to the pressure reservoir 6 through the flow passage 10.1 of its first end member 10.

5, 117984

Figure 3 shows a preferred embodiment of a pressure reservoir 6 disposed adjacent the fuel injection nozzle 5 of the cylinder head 7. Herein, the fuel pressure reservoir 6 and the injection nozzle 5 are arranged such that they can be substantially directly in contact with each other through the end piece 11 of the pressure vessel 5 only. The second end piece 11 comprises a tubular projection 11.2 arranged to extend to the injection nozzle 5 so that they together form a tight flow connection to the fuel.

The pressure reservoir 6 is arranged to comprise at least two separate chambers 6.1,6.2. In this embodiment, there are five pieces, one of which is 6.1 on the central axis of the pressure reservoir and the other is located symmetrically about the central axis, as can be seen in Figure 4. With this type of solution, the outer wall can be made thinner in wall thickness, since the pressure storage divided into partial volumes can compensate for some of the stresses caused by the pressure so that the total stress on the outer surface is reduced. Thus, the starting point is to provide a plurality of part volumes which are further interconnected in a pressure reservoir 6 suitably. Thus, according to the invention, the total volume resulting from the partial volumes is such that it is at least 30 µm. · «Times the volume of fuel injected from one

IM

. from the injection nozzle 5 during one stroke of the engine.

Thus, the pressure storage can be implemented, for example, as ** **, ·· * shown in Figures 2, 3 and 4. The pressure reservoir consists of a so-called. the main chamber 6.1 and several auxiliary chambers • · * * * 6.2. In the embodiment of FIG. the main chamber 6.1 is in direct communication with the fuel injection nozzle 5 through the end piece 11.

* · · 1: In this embodiment, fuel channels 8 are primarily connected to • · · 25 auxiliary chambers 6.2. However, all auxiliary chambers are in a flow-through · ** · .1 state. as well as with the main chamber. Creating this connection ·· «. · * ·. there are channels 6.3,6.4,6.5 arranged for sex pressure storage. Chambers 6.1.6.2 are * · «. ···. in this embodiment interconnected at both ends. The first end of the body · ♦ · * has grooves or the like 6.4,6.5, by means of which 6 117984 the chambers 6.1,6.2 are in contact with each other. Bores or the like are provided at one end 6.5. A similar function can also be achieved by a solution in which only bores parallel to its longitudinal axis are provided in the body for spaces 6.1,6.2, and all channels for connecting these are arranged in grooves, bores or the like in the end pieces 10.11.

The pressure reservoir 6 comprises an elongate body 9, preferably cylindrical in appearance, and a first end piece 10 and a second end piece 11. In this embodiment, the pressure reservoir chambers 6.1,6.2 10 comprise spaces extending from one end to one end of the body, only chamber 6.1 extends directly through the body and the other chambers 6.2 are connected to chamber 6.1 via bores or the like 6.5. Through the end pieces, fuel is introduced into the pressure reservoir 6 and further supplied to the fuel injection nozzle 5, 15. Figure 4 illustrates in more detail one way of locating the chambers in the cross section of the pressure reservoir 6. The positioning of the chambers 6.1,6.2 is preferably · · VV so that they are located substantially · · sym symmetrically with respect to the central axis of the body 9. Here, one of the chambers 6.1, which in this embodiment extends through the entire body 9, has its central axis and the other chambers. 20 6.2 symmetrically positioned in cross section. Each of the two adjacent »ti /. / Chambers is bounded by a common partition 6.3, and since the adjacent chambers * i have substantially the same pressure, the stresses caused by the pressures compensate to a considerable extent.

The invention is not limited to the embodiments shown, but many variations are conceivable within the scope of the appended claims.

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Claims (7)

7 117984 A pressure storage arrangement for the fuel supply system (1) of an internal combustion engine (2), comprising one pressure reservoir (6) for each engine cylinder, the pressure reservoir comprising a fuel inlet (10.1) and an outlet (5.1), characterized in that the inlet (10.1) and outlet (11.1) are pressurized at opposite ends of the store, and that the pressure store (6) comprises at least two separate chambers (6.1,6.2) that are in fluid communication with each other and are at least partially bounded by a common partition (6.3). Pressure storage arrangement according to claim 1, characterized in that the pressure storage (6) comprises a main chamber in fluid communication with each other and at least one auxiliary chamber, wherein said main chamber (6.1) is in fluid communication with the outlet (11.1) and said at least one auxiliary chamber (6.2) in fluid communication with the fuel inlet (10.1). Pressure storage arrangement according to one of the preceding claims, characterized in that the pressure storage (6) comprises an elongate body (9), a first end piece (10) of the body part and a second end piece of the body part. . ·. (11), wherein the pressure accumulator chambers (6.1,6.2) comprise a system arranged in the body part; and the end pieces (10.11) comprise at least one flow channel (10.1,11.1) communicating with each of said spaces. «T • · · • · *. * ··. Pressure storage arrangement according to Claim 3, characterized in that the body (9) of the pressure reservoir has a substantially circular cross-section and that the spaces (6.1,6.2) have a cross-section along the longitudinal axis of the body. substantially circular spaces such as boreholes. • · * * * {*; ./ 25 The pressure storage arrangement according to claim 3, characterized in that the spaces (6.1.6.2) are arranged in a substantially symmetrical relationship with respect to the central axis of the body section. • «* * · • · 8 117984 Pressure storage arrangement according to Claim 1, characterized in that each pressure storage (6) is arranged at least partially inside the cylinder head (7) of each cylinder of the engine (2). A pressure storage arrangement according to any one of the preceding claims, characterized in that the total volume of the pressure storage (6) is at least 30 times that of the volume of fuel injected from one injection nozzle (5) during one stroke of the engine. Φ · 1 * 1 * 1 1 * • • 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ΦΦΦ ΦΦΦ 1 1 ΦΦΦ ΦΦΦ ΦΦΦ ΦΦΦ ΦΦΦ Φ • «φ. ΦΦ φ · · • 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 »» »9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 '117984