Pulsation damping device

Abstract

To provide a pulsation damping device for reliably damping the pulsation of fluid pressure which is generated in a pipeline in a fuel supply system or the like for an internal combustion engine.SOLUTION: A pulsation damping device 1 includes an inlet pipeline 25 mounted in a spherical internal space S of a container part 20 perpendicularly to an inlet 22, and having inlet opening parts 26a, 26b at both ends, which are oppositely facing, and an outlet pipeline 27 mounted to an outlet 23 in the same structure, and having outlet opening parts 28a, 28b at both ends, which are oppositely facing, the inlet pipeline and the outlet pipeline being perpendicular to each other. Pulsation generated in fluid passing through the container part is transmitted from the inlet openings or the outlet openings into the internal space S and damped while repeating multiple reflection on the spherical inner face of the container part, and so no pulsation is transmitted to a pipe on the opposite side to the side where the cause of the pulsation exists.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a pulsation damping device that is applied to a system that supplies fluid intermittently at high pressure, such as a fuel injection system for an internal combustion engine, and that prevents pulsations from occurring in a fluid supply pipe. [Background technology]

[0002] Patent Document 1 below discloses an invention in which an auxiliary pressure accumulator (6-1) is provided in a fuel distribution pipe between the common rail and the nozzle in a common rail diesel engine. The inner surface of the auxiliary pressure accumulator is a spherical auxiliary pressure accumulator (6-2), which is said to be able to obtain injection characteristics with good response without lengthening the common rail or increasing its inner diameter.

[0003] Patent Document 2 below discloses an invention in which a pipe 3 connecting a fuel tank 1 and a feed pump 2 and a return pipe 6 connecting a fuel injection pump 5 and the fuel tank 1 in a diesel engine are each provided with a substantially spherical expansion chamber 7. This invention is said to be able to expand and absorb pressure fluctuations occurring in the pipes 3, 6.

[0004] Patent Document 3 listed below discloses an invention in which a high-pressure fuel supply system (common rail type) is provided with a low-pressure damper (5) upstream of a high-pressure fuel pump (6) and a high-pressure damper (8) downstream thereof, and further with an orifice (60) and a high-pressure regulator (10) via a branch downstream of the high-pressure damper. This invention is said to reduce pulsation in the delivery pipe and improve the durability of the high-pressure fuel supply system. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-307723 [Patent Document 3] Japanese Utility Model Application Publication No. 58-97395 [Patent Document 4] Japanese Patent Application Laid-Open No. 2001-55961 Summary of the Invention [Problem to be solved by the invention]

[0006] In a typical internal combustion engine, a fuel injection pump is provided for each of a plurality of cylinders, and during operation, each fuel injection pump is operated at a predetermined cycle to intermittently supply high-pressure fuel to each cylinder, but the operation of such fuel injection pumps can cause pulsation (periodic fluctuations) in the fuel pressure in the fuel supply pipe. Since pulsation of fuel pressure in the fuel supply pipe can vibrate the fuel supply pipe (piping system) and cause various problems, including malfunctions of components such as expansion joints, it is considered preferable to take measures to prevent this.

[0007] The invention of a diesel internal combustion engine having a spherical auxiliary pressure accumulator disclosed in Patent Document 1 is said to provide injection characteristics with good response, the invention of a fuel supply system having a substantially spherical expansion chamber disclosed in Patent Document 2 is said to be able to expand and absorb pressure fluctuations occurring in a fuel supply pipe, and furthermore, the high-pressure fuel supply device having a low-pressure damper and a high-pressure damper disclosed in Patent Document 3 is said to be able to reduce pulsation in a delivery pipe. However, in reality, these inventions have not been able to reliably suppress fuel pressure pulsation occurring in a fuel supply pipe due to operation of a fuel injection pump in an internal combustion engine.

[0008] The present invention has been made in consideration of the above-described conventional technology and the problems associated with it, and aims to provide a pulsation damping device that can be applied to a system that supplies fluid intermittently at high pressure, such as a fuel supply system for an internal combustion engine, and that can reliably damp pulsations in fluid pressure that occur within a pipeline. [Means for solving the problem]

[0009] The pulsation damping device according to claim 1 comprises: A pulsation damping device that is connected to a pipe midway to damp pulsations occurring in a fluid moving through the pipe, a container portion having a spherical internal space; an inlet opening disposed in the internal space so as to face the inner surface of the container portion and for introducing fluid from the piping into the internal space; an outlet opening portion disposed in the internal space so as to face the inner surface of the container portion and allowing the fluid in the internal space to flow out to the piping; Equipped with The axis of the piping on the inlet side that communicates with the inlet opening and the axis of the piping on the outlet side that communicates with the outlet opening are arranged so as to coincide with one central axis of the spherical internal space.

[0010] The pulsation damping device according to claim 2 is the pulsation damping device according to claim 1, In the internal space, an inlet pipe is connected to an end of the pipe on the inlet side so as to be perpendicular to an axis of the pipe, The inlet pipe has a first inlet opening and a second inlet opening at both ends thereof, the first inlet opening and the second inlet opening being in two inflow directions that are 180 degrees apart from each other, In the internal space, an outlet pipe is connected to an end of the pipe on the outlet side so as to be perpendicular to an axis of the pipe and the inlet pipe, The outlet pipeline is characterized in that a first outlet opening and a second outlet opening, whose outflow directions are two directions that are 180 degrees different from each other, are formed at both ends of the outlet pipeline at positions that correspond to the positions of the first inlet opening and the second inlet opening when the inlet pipeline is rotated 90 degrees around the axis of the piping. [Effects of the Invention]

[0011] According to the invention described in claim 1, a pressurized fluid moving through a pipe flows into a spherical internal space of a container filled with the fluid and then flows out into a pipe outside the internal space. Suppose that the fluid moving through the pipe outside the container experiences pulsation, i.e., a phenomenon in which the fluid's pressure fluctuates irregularly over a relatively short period, for some reason. This pulsation propagates from the inlet or outlet opening into the internal space of the container regardless of the direction of the fluid flow. It then collides with the spherical inner surface of the container, reflects off, and then undergoes multiple reflections, changing its direction. The pulsation propagating through the fluid filling the internal space of the container is gradually attenuated by multiple reflections on the spherical inner surface of the container, and is therefore hardly transmitted to the fluid flowing out of the container through the inlet or outlet opening into the pipe outside the container. In other words, even if pulsation occurs in the fluid in the pipe, after the fluid passes through the pulsation attenuation device, the pulsation is sufficiently attenuated and does not propagate to the pipe on the opposite side of the side where the pulsation occurred.

[0012] According to the invention described in claim 2, when pulsation generated in the pipe enters through the inlet opening, the inflow direction of the fluid from the first inlet opening and the inflow direction of the fluid from the second inlet opening are opposite to each other, thereby achieving multiple reflection of the pulsation starting from two different positions on the inner surface of the container. Furthermore, the fluid whose pulsation has been attenuated by multiple reflection flows out of the container through the downstream pipe from two locations, the first outlet opening and the second outlet opening, which are located at two different positions downstream along the axis of the pipe. Here, in terms of the positions in the rotational direction around the axis of the pipe, the first outlet opening and the second outlet opening are located at positions that are 90 degrees different from the first inlet opening and the second inlet opening. Therefore, the pulsation of the fluid flowing in through the first inlet opening and the second inlet opening is weakened by multiple reflection, and then further attenuated by multiple reflection before reaching the first outlet opening and the second outlet opening, and then flows out of the internal space, thereby reliably achieving a greater effect in terms of pulsation attenuation. Conversely, the same effect can be obtained in the case where pulsation generated in the piping enters through the outlet opening and is attenuated by multiple reflections. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a piping diagram of an internal combustion engine provided with a pulsation damping device of a first embodiment. [Figure 2] 2 is a perspective view showing the internal structure of the pulsation damping device of the first embodiment, seen through a container portion. FIG. [Figure 3] FIG. 1 is a front view of a pulsation damping device according to a first embodiment. [Figure 4] 1 is a plan view of a pulsation damping device according to a first embodiment. FIG. [Figure 5] FIG. 4 is a cross-sectional view taken along the line AA in FIG. [Figure 6] FIG. 5 is a cross-sectional view taken along line BB in FIG. 4. [Figure 7] 2 is a graph showing the change over time in fuel pressure at the injection port of the fuel injection pump of the No. 1 cylinder in the piping system diagram of FIG. 1. [Figure 8] 2 is a graph showing the change over time in pressure in a fuel oil pipe as measured by a pressure gauge P5 in the piping system diagram of FIG. 1. [Figure 9] 2 is a graph showing the change over time in pressure in a fuel oil pipe at a pressure gauge P3 in the piping system diagram of FIG. 1. [Figure 10] 2 is a graph showing the change over time in pressure in a fuel oil pipe as measured by a pressure gauge P1 in the piping system diagram of FIG. 1. [Figure 11] 2 is a graph showing the change over time in pressure in a fuel oil pipe as measured by a pressure gauge P6 in the piping system diagram of FIG. 1. [Figure 12] 2 is a graph showing the change over time in pressure in the fuel oil pipe at a pressure gauge P4 in the piping system diagram of FIG. 1. [Figure 13] 2 is a graph showing the change over time in pressure in the fuel oil pipe at a pressure gauge P2 in the piping system diagram of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described with reference to the drawings. Fig. 1 schematically shows a fuel pipe 3 of an internal combustion engine 2 provided with a pulsation damping device 1 (1a, 1b) of the embodiment, and the engine 2 connected to the fuel pipe 3. Note that the pulsation damping device 1 is also called an accumulator as shown in Fig. 1, and the internal combustion engine 2 is sometimes simply called the engine 2 for short.

[0015] In the illustrated example, the internal combustion engine 2 is a multi-cylinder diesel engine having six cylinders, numbered from cylinder 1 to cylinder 6. As shown in Fig. 1, each cylinder is equipped with a fuel injection valve FV that injects fuel into the cylinder, and a fuel injection pump FIP that supplies fuel to the fuel injection valve FV. The fuel inlet sides of the fuel injection pumps FIP are connected in parallel to a main fuel inlet pipe 4 of the engine 2, and the fuel return sides are connected in parallel to a main fuel outlet pipe 5 of the engine 2.

[0016] As shown in Fig. 1, the main fuel inlet pipe 4 and the main fuel outlet pipe 5, which are pipes on the engine 2 side, are connected to a fuel pipe 3 provided outside the engine 2. The fuel pipe 3 includes a supply pipe 3a that connects a fuel storage tank 6 (shown as an A-type heavy oil head tank in Fig. 1) with an engine inlet 7, and a return pipe 3b that connects an engine outlet 8 with partway through the supply pipe 3a.

[0017] As shown in Fig. 1, the upstream starting end of supply pipe 3a is connected to fuel storage tank 6. Then, supply pipe 3a is provided with, from upstream to downstream, a fuel oil filter 9, a flow meter 10, a bypass passage 11 connecting the upstream side of fuel oil filter 9 with the downstream side of flow meter 10, a normally closed gate valve 12 provided in bypass passage 11, a normally open gate valve 13, a check valve 14, a fuel circulation pump 15, a normally closed gate valve 16, and a line heater 17 connecting the upstream and downstream sides of normally closed gate valve 16. Then, the downstream end of supply pipe 3a is connected to engine inlet 7, which is the most upstream end of fuel inlet main pipe 4, via first pulsation damping device 1a.

[0018] As shown in Fig. 1, the start end on the upstream side of the return pipe 3b is connected to the engine outlet 8, which is the most downstream end of the main fuel outlet pipe 5. The return pipe 3b is first connected to the second pulsation damping device 1b, and downstream of the second pulsation damping device 1b, a pressure regulating valve 18 and a fuel oil cooler 19 are provided in this order, and the end end on the downstream side of the second pulsation damping device 1b is connected to the supply pipe 3a between the check valve 14 and the fuel injection pump 15.

[0019] As shown in FIG. 1 , the fuel piping 3 of the engine 2 in this embodiment is provided with a plurality of pressure gauges to examine pressure pulsations that are generated in the fuel oil in the main fuel inlet pipe 4 and the main fuel outlet pipe 5 due to operation of the fuel injection pump FIP and that are transmitted to the fuel oil in the fuel piping 3. The supply piping 3a is provided with a pressure gauge P1 on the upstream side (farther from the engine 2) of the first pulsation damping device 1a and a pressure gauge P5 on the downstream side (closer to the engine 2), and the first pulsation damping device 1a is provided with a pressure gauge P3. The return piping 3b is provided with a pressure gauge P2 on the downstream side (farther from the engine 2) of the second pulsation damping device 1b and a pressure gauge P6 on the upstream side (closer to the engine 2), and the second pulsation damping device 1b is provided with a pressure gauge P4. Although not shown, a pressure gauge is also provided between the discharge port of the fuel injection pump FIP of the No. 1 cylinder and the inlet of the fuel injection valve FV.

[0020] The structures of the first and second pulsation damping devices 1 (1a, 1b) will be described with reference to FIGS. The first pulsation damping device 1a and the second pulsation damping device 1b have the same structure. This pulsation damping device 1 has the function of damping fuel pulsation transmitted from the upstream or downstream side when fuel passes in a predetermined direction in its internal space, thereby preventing the pulsation from being transmitted to the opposite side, that is, the downstream or upstream side. As mentioned above, this pulsation damping device 1 is also called an "accumulator" in the sense that pressurized fuel is held in its internal space.

[0021] The pulsation damping device 1 has a container 20 with a spherical outer shape that is sealed from the outside and a spherical internal space S. That is, the container 20 is a hollow sphere, but the container 20 of the embodiment is made up of two hemispherical parts having annular flanges 21 for connection, and the two parts are abutted at the flanges 21 and integrated with bolts (not shown).

[0022] The container 20 is provided with an inlet 22 and an outlet 23 through which fuel flows in and out. The inlet 22 and the outlet 23 are conduits that communicate with the fuel pipe 3 and are aligned with the axis of the fuel pipe 3. Annular flanges 24 are provided at the outer ends of the inlet 22 and the outlet 23 for connection to the pipes. The central axes of the inlet 22 and the outlet 23 are aligned with one central axis of the spherical internal space S. In other words, the inlet 22 and the outlet 23 are on a straight line, and this straight line passes through the center of the spherical internal space S.

[0023] In the internal space S of the container 20, the central portion of a cylindrical inlet pipe 25 is connected to the end of the inlet 22 so as to be perpendicular to the axes of the fuel pipe 3 and the inlet 22. That is, the fuel pipe 3, the inlet 22, and the inlet pipe 25 are connected in a T-shape and communicate with each other. At both ends of the inlet pipe 25, a first inlet opening 26a and a second inlet opening 26b are formed, with fuel flow directions being 180 degrees apart from each other. The first inlet opening 26a and the second inlet opening 26b face the spherical inner surface of the container 20. The first inlet opening 26a and the second inlet opening 26b are formed as short pipes with round holes.

[0024] In the internal space S of the container 20, a central portion of a cylindrical outlet pipe 27 is connected to the end of the outlet 23 so as to be perpendicular to the axes of the fuel pipe 3 and the outlet 23. That is, the fuel pipe 3, the outlet 23, and the outlet pipe 27 are connected in a T-shape and communicate with each other. A first outlet opening 28 and a second outlet opening 28 are formed at both ends of the outlet pipe 27, with fuel inflow directions in two directions that are 180 degrees apart from each other. The first outlet opening 28a and the second outlet opening 28b face the spherical inner surface of the container 20. The first outlet opening 28a and the second outlet opening 28b are formed as short pipes with round holes.

[0025] Thus, although the inlet pipe 25 and the outlet pipe 27 have the same external shape, for example, in FIG. 2, if the axes of the fuel pipe 3 (not shown) and the inlet 22 (or outlet 23) are considered as rotation axes, the inlet pipe 25 and the outlet pipe 27 are positioned at positions that differ from each other by 90 degrees in the rotational direction. That is, the longitudinal direction of the inlet pipe 25 and the longitudinal direction of the outlet pipe 27 are perpendicular to each other. For example, if the inlet pipe 25 is rotated 90 degrees counterclockwise in FIG. 2 around the axis of the inlet 22, the rotational positions of the first inlet opening 26a and the second inlet opening 26b will coincide with the rotational positions of the first outlet opening 28a and the second outlet opening 28b. The above-described positional relationship between the two inlet openings 26a, 26b and the two outlet openings 28a, 28b is clear from FIG. 2 as described above, but can also be understood by comparing FIG. 3 and FIG. 4.

[0026] The operation and effect of the pulsation damping device 1 in the fuel pipe 3 of the internal combustion engine 2 of the embodiment will be described with reference to the position of the pressure gauge shown in FIG. 1 and the fuel pressure waveforms shown in FIGS. In order to demonstrate the pulsation damping effect of the pulsation damping device 1 of this embodiment, the pressure waveforms of fuel oil obtained by the seven pressure gauges will be compared and explained for the case where the engine 2 is driven without the pulsation damping device 1 in the fuel piping 3 shown in Figure 1 (corresponding to the case where the piping before and after the pulsation damping device 1 is directly connected; this is called the comparative example) and the case where the engine 2 is driven in the fuel piping 3 having the pulsation damping device 1 shown in Figure 1 (embodiment).

[0027] Of the seven pressure gauges mentioned above, the pressure waveforms obtained by the pressure gauges P3 and P4 provided in the pulsation damping device 1 (1a, 1b) are naturally not included in the comparative example, but are only obtained in the embodiment. In addition, in the fuel oil pressure waveform diagrams shown in Figures 7 to 13, the waveforms of the comparative example without the pulsation damping device 1 ("without accumulator") are shown by dashed lines, and the waveforms of the embodiment with the pulsation damping device 1 ("with accumulator") are shown by solid lines.

[0028] As shown in Fig. 7, when the engine 2 is driven and the fuel injection pump FIP is operated, the fuel oil pressure is measured as a sharp pulse-like waveform in the fuel injection pipe on the discharge side of the fuel injection pump FIP in both the comparative example and the embodiment. In Fig. 7, the pulse-like waveform in the comparative example without the pulsation damping device 1 ("without accumulator") is shown to rise slightly earlier than in the embodiment with the pulsation damping device 1 ("with accumulator"), but this is shown with a slight shift to make it clear that the waveforms are substantially the same in both cases. In reality, even though the fuel injection pump FIP is driven at the same timing, the presence or absence of the pulsation damping device 1 does not shift the fuel injection timing or change the timing at which the pulse-like waveform rises.

[0029] When the engine 2 is driven, the fuel injection pumps FIP corresponding to cylinders No. 1 to No. 6 operate in a predetermined sequence and at predetermined intervals, causing a pulse-like waveform of fuel oil as shown in Figure 7 to be generated one after another on the discharge side of each fuel injection pump FIP. Due to pressure fluctuations that occur in the fuel oil as a result of the operation of multiple fuel injection pumps FIP, pulsations in which the pressure fluctuates at short, irregular intervals occur in the fuel oil in the main fuel inlet pipe 4 that supplies fuel to the fuel injection pump FIP and in the main fuel outlet pipe 5 through which uninjected fuel flows back from the fuel injection pump FIP.

[0030] As shown in Fig. 8, according to the results of measurements taken by a pressure gauge P5 on the downstream side (engine 2 side) of the first pulsation damping device 1a in the supply piping 3a, both the pressure waveform of the comparative example ("without accumulator") not including the pulsation damping device 1a and the pressure waveform of the embodiment ("with accumulator") including the pulsation damping device 1a irregularly fluctuate up and down (oscillate) in short cycles, as can be seen from the scale on the horizontal axis (time axis), and the pulsation is not eliminated. However, the pressure waveform (solid line) of the embodiment ("with accumulator") including the pulsation damping device 1a has a significantly smaller range of pressure fluctuation than the pressure waveform (dashed line) of the comparative example ("without accumulator") not including the pulsation damping device 1a. In other words, the pulsation is damped in the embodiment ("with accumulator") including the pulsation damping device 1a.

[0031] 9, according to the results of measurement by the pressure gauge P3 inside the first pulsation damping device 1a, almost no pressure fluctuations occur in the internal space S of the first pulsation damping device 1a, and the pressure is maintained almost constant. It can be said that the pulsation that had occurred in the fuel oil on the engine 2 side (fuel inlet main pipe 4) of the first pulsation damping device 1a has almost disappeared in the internal space S of the first pulsation damping device 1a.

[0032] 10, according to the results of measurements taken by a pressure gauge P1 on the upstream side of the first pulsation damping device 1a (the side opposite the engine 2) in the supply piping 3a, the pressure waveform (dashed line) of the comparative example ("without accumulator") which does not have the pulsation damping device 1a shows severe pulsation, whereas the pressure waveform (solid line) of the embodiment ("with accumulator") which has the pulsation damping device 1a shows almost no pressure fluctuations and the pressure is maintained almost constant. The pulsation which had been generated in the fuel oil on the engine 2 side of the first pulsation damping device 1a has almost disappeared in the internal space S of the first pulsation damping device 1a as described above, and therefore is not transmitted to the fuel oil in the supply piping 3a on the side opposite the engine 2 with respect to the first pulsation damping device 1a.

[0033] As shown in Fig. 11, according to the results of measurements taken by a pressure gauge P6 on the upstream side (engine 2 side) of the second pulsation damping device 1b in the return pipe 3b, both the pressure waveform of the comparative example ("without accumulator") not including the pulsation damping device 1b and the pressure waveform of the embodiment ("with accumulator") including the pulsation damping device 1b irregularly fluctuate up and down (oscillate) in short cycles, as can be seen from the scale on the horizontal axis (time axis), and the pulsation is not eliminated. However, the pressure waveform (solid line) of the embodiment ("with accumulator") including the pulsation damping device 1b has a significantly smaller range of pressure fluctuation than the pressure waveform (dashed line) of the comparative example ("without accumulator") not including the pulsation damping device 1b. In other words, the pulsation is damped in the embodiment ("with accumulator") including the pulsation damping device 1b.

[0034] 12, according to the results of measurements made by the pressure gauge P4 inside the second pulsation damping device 1b, almost no pressure fluctuations occur in the internal space of the second pulsation damping device 1b, and the pressure is maintained almost constant. It can be said that the pulsation that had occurred in the fuel oil on the engine 2 side (fuel outlet main pipe 5) of the second pulsation damping device 1b has almost disappeared in the internal space S of the second pulsation damping device 1b.

[0035] 13, according to the results of measurement by the pressure gauge P2 on the downstream side of the second pulsation damping device 1b in the return pipe 3b (the side opposite the engine 2), the pressure waveform (dashed line) of the comparative example ("without accumulator") in which there is no pulsation damping device 1b shows severe pulsation, whereas the pressure waveform (solid line) of the embodiment ("with accumulator") in which there is the pulsation damping device 1b shows almost no pressure fluctuations and the pressure is maintained almost constant. The pulsation that had been generated in the fuel oil on the engine 2 side of the second pulsation damping device 1b has almost disappeared in the internal space S of the second pulsation damping device 1b as described above, and therefore is not transmitted to the fuel oil in the return pipe 3b on the side opposite the engine 2 with respect to the second pulsation damping device 1b.

[0036] As described above, in the fuel piping 3 of the embodiment, firstly, the effect of greatly attenuating fuel oil pulsation is obtained on the engine 2 side of the two pulsation damping devices 1 (1a, 1b). Therefore, in both the fuel inlet main pipe 4 and the fuel outlet main pipe 5, which are piping on the engine 2 side, pulsation occurring in the fuel is suppressed, and there is little risk that the fuel pulsation will adversely affect these piping on the engine 2 side and the associated equipment (for example, the fuel injection pump FIP).

[0037] Next, the effect of almost completely eliminating fuel oil pulsation is achieved on the side (storage tank 6 side) of the two pulsation damping devices 1 (1a, 1b) opposite the engine 2. The two pulsation damping devices 1 (1a, 1b) are arranged so that they are almost directly connected to the engine inlet 7 and engine outlet 8 of the fuel piping 3 connecting the storage tank 6 and the engine 2, and no particular equipment is provided between the engine 2 and the two pulsation damping devices 1 (1a, 1b). For this reason, almost the entire length of the fuel piping 3 and the various equipment provided in the fuel piping 3 are not exposed to fuel oil pulsation, and even when the engine 2 is used continuously for a long period of time, there is little risk that the connection parts of the fuel piping 3 or the various equipment will be affected by the pulsation and their functions will be reduced.

[0038] In the pulsation damping device 1 of the embodiment described above, as shown in Fig. 2, when the axis of the inlet 22 or the outlet 23, which coincides with the axis of the external fuel pipe 3, is considered as the axis of rotation, the inlet pipe 25 and the outlet pipe 27 of the internal space S are arranged at positions that differ from each other by 90 degrees in the rotation direction, and their longitudinal directions are perpendicular to each other. The inventors of the present application have confirmed that a significant effect of pulsation damping is achieved by setting the intersection angle between the inlet pipe 25 and the outlet pipe 27 in the pulsation damping device 1 to 90 degrees, but because pulsation within the spherical internal space S is damped, the intersection angle is not particularly limited to this, and depending on the conditions, the intersection angle may be 0 degrees or 180 degrees, i.e., may be parallel to each other, and the pulsation damping effect may also be obtained at angles other than these.

[0039] That is, in the pulsation damping device 1 of the embodiment, the situation in which pulsation occurs in the fuel oil is affected by various conditions such as the specific configuration and operating conditions of the engine 2 and the fuel piping 3, so in implementing the present invention, it is preferable to determine the intersection angle between the outlet pipe 27 and the inlet pipe 25 in the pulsation damping device 1 to be an optimal value while taking into consideration the various conditions. [Explanation of symbols]

[0040] 1, 1a, 1b... Pulsation damping device (accumulator) 2...Internal combustion engine (engine) 3…Fuel piping 3a…Supply piping 3b...Return pipe 4…Fuel inlet main pipe 5…Fuel outlet main pipe 20...Container part 22…Entrance 23...Exit 25...Inlet pipe 26a...first inlet opening 26b...second entrance opening 27...Outlet pipe 28a...first outlet opening 28b...second exit opening S…interior space

Claims

1. A pulsation damping device that is connected to a pipe midway to damp pulsations occurring in a fluid moving through the pipe, a container portion having a spherical internal space; an inlet opening disposed in the internal space so as to face the inner surface of the container portion and for introducing fluid from the piping into the internal space; an outlet opening portion disposed in the internal space so as to face the inner surface of the container portion and allowing the fluid in the internal space to flow out to the piping; Equipped with A pulsation damping device characterized in that the axis of the piping on the inlet side communicating with the inlet opening and the axis of the piping on the outlet side communicating with the outlet opening are arranged so as to coincide with one central axis of the spherical internal space.

2. In the internal space, an inlet pipe is connected to an end of the pipe on the inlet side so as to be perpendicular to an axis of the pipe, a first inlet opening and a second inlet opening are formed at both ends of the inlet pipe, the first inlet opening and the second inlet opening having inflow directions that are 180 degrees apart from each other; In the internal space, an outlet pipe is connected to an end of the pipe on the outlet side so as to be perpendicular to an axis of the pipe and the inlet pipe, 2. The pulsation damping device according to claim 1, wherein the first outlet opening and the second outlet opening, whose outflow directions are two directions that are 180 degrees different from each other, are formed at both ends of the outlet pipe at positions that correspond to the positions of the first inlet opening and the second inlet opening when the inlet pipe is rotated 90 degrees around the axis of the piping.

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