JPH10299609A - Pulsation reducing damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulsation reducing damper capable of effectively reducing pulsation in relation to a wide range of fluid pressure. SOLUTION: This pulsation reducing damper 39 is provided with plural gas filled chambers 47, 55, plural flexible partition walls 49, 53 supported by gas pressure in the respective gas filled chambers, and a common pressure receiving chamber 59 allowing fluid pressure to act on the partition walls respectively, and the respective flexible partition walls 49, 53 are structured to have different pulsation reducing characteristics. By this constitution, pressure pulsation can be reduced in relation to a wide range of fluid pressure which the pressure receiving chamber 59 receives.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pulsation reducing damper for reducing pulsation in a fluid passage communicating with a pressure receiving chamber.
In particular, it relates to a pulsation reducing damper in which gas is sealed in a back pressure chamber.

[0002]

2. Description of the Related Art In general, a gas-filled damper mounted on a fuel injection pump is known as this kind of pulsation reducing damper. This damper is a gas chamber (back pressure chamber) in which gas is filled. And a diaphragm (flexible partition) supported by the gas pressure in the gas chamber. This conventional damper generally has one gas chamber,
A single diaphragm supported by the gas chamber is provided. The diaphragm faces one pressure receiving chamber and receives a pulsation. The gas is sealed in the gas chamber at a predetermined sealing pressure.

On the other hand, Japanese Patent Laying-Open No. 60-24074 discloses a configuration in which two dampers are provided in one housing. In each of the dampers disclosed in this publication, the diaphragm (partition wall) is held by a compression spring, and the pressure receiving chamber of each damper is connected to a separate fluid passage to reduce pulsation in each fluid passage. I have.

[0004]

However, in the former damper, since the pressure in the gas chamber is fixed, it is necessary to individually set the pressure in the gas chamber according to the set pressure of the fluid received by the pressure receiving chamber. There is. That is, as shown by the broken line in FIG. 2, the range of the fluid pressure in which one damper can effectively reduce the pulsation is narrow and limited, so that the range of the variable fuel pressure (for example, 6.25 to 9.75 MPa) is reduced. There is a problem that pulsation cannot be effectively reduced. Further, the conventional damper has a problem that a pulsation reduction damper having a different gas pressure must be separately mounted in accordance with the set pressure of the fluid passage. FIG. 2 shows the set pressure on the vertical axis and the pulsation width at the peak on the horizontal axis.

On the other hand, in the latter damper, two dampers are arranged in a casing, but different flow paths (pressure receiving chambers) are used.
Are provided with separate dampers, respectively.
Since one damper is integrally formed, one flow path (pressure receiving chamber) is substantially the same as a configuration having one damper, similarly to the above-described conventional damper, and the set pressure of the flow path is set. However, the point that the pulsation reduction damper having a different back pressure must be separately used according to the present invention is not changed. That is, the conventional damper has a problem that the range of usable fluid pressure is limited to a narrow range.

Accordingly, an object of the present invention is to provide a pulsation reducing damper capable of effectively reducing pulsation over a wide range of fluid pressures.

[0007]

According to one aspect of the present invention, there is provided a fuel cell system comprising: a plurality of gas filling chambers; and a plurality of flexible partition walls supported by a gas pressure of each gas filling chamber. When,
A pulsation reducing damper including a common pressure receiving chamber for applying a fluid pressure to each partition, wherein the plurality of flexible partitions have different pulsation reducing characteristics.

According to the first aspect of the present invention, flexible partition walls having different pulsation reduction characteristics are provided, and these flexible partition walls act on a common pressure receiving chamber. In addition, the pressure pulsation can be reduced for a wide range of fluid pressure. Moreover, since the damper is a gas-filled damper, the structure is easy. The pulsation reducing damper can be used in various fluid circuits such as a fuel injection circuit, a hydraulic circuit, and a water pipe. Further, the flexible partition refers to a diaphragm, a membrane, or the like.

According to a second aspect of the present invention, in the first aspect of the invention, at least one of the sealed gas pressure and the gas sealed chamber volume of each of the gas sealed chambers is different for each gas sealed chamber. It is a feature.

According to the second aspect of the invention, since the gas pressures and the volumes of the gas filling chambers are different in each gas filling chamber, the flexibility supported by the gas pressure of the gas filling chambers. The pulsation reduction characteristics of the partition can be made different with a simple configuration. In addition, by setting the gas pressure and the volume of each gas filled chamber, the pulsation reduction characteristics of each flexible partition can be made different easily and can be easily set to any desired characteristics.

According to a third aspect of the present invention, in the first aspect of the present invention, the pressure receiving area of the flexible partition provided in the gas filling chamber is made different.

According to the third aspect of the present invention, since the pressure receiving areas of the flexible partitions are different in each gas filled chamber, the opening area of the gas filled chamber in which each flexible partition is provided is reduced. By simply changing the pulsation, the pulsation reduction characteristics of each flexible partition can be easily made different, and can be easily set to an arbitrary characteristic.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the plurality of gas-filled chambers communicate with each other, and the volume of each gas-filled chamber and the pressure receiving area of the flexible partition wall are reduced. At least one of them is different for each gas filled chamber.

According to the fourth aspect of the present invention, the gas pressures of the gas filling chambers are equalized by communicating the gas filling chambers, but the volume of the gas filling chambers and the pressure receiving area of the flexible partition wall. Therefore, each flexible partition can obtain different pulsation reduction characteristics. That is, when the pressure received by the pressure receiving chamber is a high set pressure, each flexible partition is greatly deformed and the volume of each gas sealing chamber is reduced, thereby increasing the gas pressure. On the other hand, pulsation can be reduced. On the other hand, if the set pressure received by the pressure receiving chamber is small, the deformation of the flexible partition wall is small, and the volume of each gas filled chamber is large, so that the gas pressure which is the back pressure is small, and the set pressure of the low pressure received by the pressure receiving chamber is reduced. On the other hand, pulsation can be reduced.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG.
The first embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 is a cross-sectional view of a fuel injection pump equipped with a diaphragm type damper according to an embodiment of the present invention, cut from the front side, and FIG. 2 shows pulsation when the set pressure of the fuel injection pump is variously changed. It is a graph which shows the reduction effect compared with the former.

The fuel injection pump 3 according to the present embodiment
Injects gasoline directly into the combustion chamber of a gasoline engine, and is used in a fuel supply system referred to as a so-called direct injection gasoline engine to pump high-pressure gasoline.

The fuel injection pump 3 includes a plunger 5
And a plunger 5
And a lower main body (not shown) in which a cam 9 for driving the cam is stored. The cam 9 is connected to a shaft driven by an engine (not shown). The cam 9 rotates by driving of the engine, and the cam 9 comes into circumferential contact with a cam contact shoe 11 disposed at a lower end of the plunger 5. It is configured to be driven up and down.

The pump housing 7 is provided with a suction port 13 for supplying low-pressure fuel and a discharge port 17 for discharging fuel pressurized by the plunger 5.

The suction port 13 is connected to a pump chamber (fuel compression chamber) 21 through a fuel supply passage 19 formed in the pump housing 7, and the discharge port 17 is connected to the pump chamber 21 through a fuel discharge passage 23. When the valve opens and closes, the fuel compressed in the pump chamber 21 is discharged to the discharge port 17.
Is discharged from.

A fixed member 29 is screwed into a large-diameter hole formed in the pump housing 7, and a plunger barrel 33 for guiding sliding of the plunger 5 is fixed inside the fixed member 29. ing.

On the other hand, a push rod 24 is interposed between the plunger 5 and the above-mentioned cam contact shoe 11, and the plunger 5 is pressed through the push rod 24 to slide into the plunger barrel 33. The plunger 5 slides up and down along the plunger barrel 33. The lower end of a spring 35 is in contact with the plunger 5, and the spring 35 constantly urges the plunger 5 downward, and the upper end of the spring 35 is supported by the lower surface of the fixing member 37. ing. Further, a pump chamber 21 for pressurizing the fuel is formed between the lower surface of the fixing member 37 and the plunger 5.

The plunger barrel 33 includes a plunger 5
At the lower end (opposite the pump chamber) of the plunger 5
Pulsation reducing space 26 defined by the push rod 24
Are formed. The pulsation reducing space 26 communicates with the fuel suction port 13 through a low-pressure passage 28 to reduce pulsation on the low-pressure side generated by the reciprocating operation of the pump chamber 21. That is, the pulsation reduction space 26 is
When the plunger 5 descends, the fuel in the pulsation reducing space 26 is returned to the fuel supply passage 19 through the first low-pressure passage 28, and when the plunger 5 rises, the suction port 13 is formed. The fuel is sucked into the pulsation reduction space 26 from the side through the fuel supply passage 19. In the present embodiment, the volume ratio between the pulsation reducing space 26 and the pump chamber 21 is, for example, 1: 2, and the suction amount at the suction port 13 is lower when the plunger 5 is lowered.
The return amount from the pulsation reducing space 26 is 1 with respect to the volume ratio 2 of the fuel sucked into the pump chamber 21. When the plunger 5 is raised, fuel is supplied only from the fuel supply passage 19 to the pulsation reducing space 26. The return amount to the suction port 13 becomes -1. Therefore, the volume ratio of the fuel sucked from the suction port 13 becomes 1 as a whole when the plunger 5 is lowered and when it is raised. This eliminates intermittent pulsation of suction at the suction port 13 side.

On the other hand, the fuel discharge passage 23 passes through a high-pressure damper 39 provided in the upper part of the pump housing 7, and this high-pressure damper 39 suppresses high-pressure pulsation in the fuel discharge passage 23.

Here, the high-pressure damper (pulsation reduction damper) 39 according to the present invention will be described. High pressure damper 39
Includes a case 41 and a first fixing member 43 and a second fixing member 45 fixed in the case 41. A first gas filling chamber 47 is formed in the first fixing member 43, and a first diaphragm (flexible partition) 49 is provided at an opening thereof. The first diaphragm 49 and the first fixing member 43 are provided.
Thus, a first gas filling chamber 47 is defined.

The second fixing member 45 includes the second gas filling chamber 5.
5 is formed, and a second diaphragm (flexible partition) 53 is provided in the opening thereof. The first diaphragm 53 and the second fixing member 45 form a second gas filling chamber 55.
Is defined.

An intermediate member 57 is interposed between the first fixing member 43 and the second fixing member 45.
7 includes a first diaphragm 49 and a second diaphragm 5
3 is formed facing the pressure receiving chamber 59.
Therefore, two first and second diaphragms 49 and 53 act on one pressure receiving chamber 59 at the same time.

On the other hand, in the first embodiment, the first gas filling chamber 47 and the second gas filling chamber 55 have substantially the same volume, and the pressure receiving areas of the first and second diaphragms 49 and 53 are also small. Although substantially equal, the gas filling pressures of the first gas filling chamber 47 and the second gas filling chamber 55 are different. For example, in the present embodiment, the gas filling pressure of the first gas filling chamber 47 is about 70 atm, and the gas filling pressure of the second gas filling chamber 55 is about 50 atm. The pulsation reduction characteristics of the first diaphragm 49 and the second diaphragm 53 are made different by the different gas filling pressures. Specifically, the first diaphragm 49 can mainly cope with high-pressure pulsation since the gas pressure supporting the first diaphragm 49 is high, and the second diaphragm 53
Since the gas pressure supporting this is low, the pulsation in each pressure region is reduced mainly corresponding to the low-pressure pulsation. Therefore, the pulsation in a wide range of fluid pressure with respect to the fluid pressure in the pressure receiving chamber can be effectively reduced, and the pulsation can be effectively reduced even in the variable fuel pressure.

The pressure receiving chamber 59 is communicated with the fuel discharge passage 23 through a discharge passage 61 formed in the intermediate member 57 and a discharge passage 63 formed in the case 41, and pulsation is reduced in the pressure receiving chamber 59. After that, the fuel is discharged from the discharge port 17.

In FIG. 1, reference numerals 65 and 67 are stoppers for filling gas into the gas filling chambers 47 and 55, respectively.

Next, the operation of the first embodiment will be described. When the cam 9 rotates, the plunger 5 moves up and down via the cam contact shoe 11, whereby fuel is supplied to the pump chamber 21 through the fuel supply path 19 and the fuel in the pump chamber 21 is removed. Pressurized and discharged to the discharge passage 23.

The fuel introduced into the fuel discharge passage 23 is discharged from the discharge port 17 after the pulsation is reduced by the high-pressure damper 39 through the communication passages 63 and 61. That is, in the high-pressure damper 39, the pressure receiving chamber 59 receives the pulsation of the pump chamber via the discharge passages 63 and 61. In the pressure receiving chamber 59, flexible partitions having different pulsation reduction characteristics are provided at positions facing each other. Since it is provided, the pulsation is reduced with respect to the discharge pressure in a wide range. Therefore, the fuel injection pump 3
The pulsation can be reduced in this variable range even when the supply pressure at becomes a variable fuel pressure. Alternatively, even if the set pressure of the fuel supply pressure is different, one high pressure damper 39
It is not necessary to easily change the gas filling pressure or the like according to the set pressure.

That is, in an experiment of pulsation reduction using the damper according to the present embodiment, as shown in FIG. 2, pulsation could be effectively reduced in a wide range of set pressure.
In FIG. 2, the pressure regulator (P /
The set pressure of R) is taken, and the pulsation width at the peak is taken on the vertical axis. In the experiment, the set pressure of the pressure regulator (P / R) in the discharge passage was changed variously, and the rotational speed of the engine driving the high-pressure pump was increased to 1000 r / mi.
The pulsation width was measured in the case of n and 3000 r / min. As is clear from FIG.
According to the present embodiment, as compared with the conventional damper indicated by a broken line in FIG.
The pulsation can be effectively reduced with respect to the variable pressure in a wide range of a).

Hereinafter, the second and third embodiments of the present invention will be described. The same parts as those in the above-described first embodiment are denoted by the same reference numerals, and the detailed description of those parts is given. Is omitted.

The high-pressure damper 39 according to the second embodiment shown in FIG. 3 includes a fixed member 67 in a case 41. The first gas sealing chamber 69 and the Two gas filling chambers 71 are formed, and two gas filling chambers 69 and 71 are provided on both sides of one fixed member 67. First and second gas filling chambers 6
The capacities of the gas filling chambers 9 and 71 are different, and in the present embodiment, the capacity of the first gas filling chamber 69 is set to be larger than the capacity of the second gas filling chamber 71. Further, the first gas filling chamber 69
And the second gas filling chamber 71 communicate with the gas filling chamber communication passage (communication passage)
The gas pressures of the two are always equal. Also, with this configuration,
Only one gas filling point is required, and the configuration is simple.

Further, the first diaphragm 49 is supported by the first gas filling chamber 69, and the second diaphragm 53 is supported by the second gas filling chamber 71. In these first and second diaphragms 49 and 53, pressure receiving chambers 79 and 81 are formed in fixed members 75 and 77, respectively. The pressure receiving chambers 79 and 81 are connected to the fuel discharge passage 23 by communication passages 83 and 85, respectively. Are in communication.

According to the second embodiment, since the two gas-filled chambers 69 and 71 are communicated with the gas-filled-chamber communication passage 73, the gas pressures of the gas-filled chambers 69 and 71 become equal. Since the gas filling chambers have different volumes, each of the flexible partitions 49 and 53 has different pulsation reduction characteristics. That is, at a high set pressure, the flexible partition walls 49 and 53 are deformed to reduce the volume of each of the gas filling chambers 69 and 71 and the gas pressure of each of the gas filling chambers 69 and 71 becomes high. Pulsation can be reduced with respect to pressure. On the other hand, if the set pressure is small, the deformation of the flexible partition wall is small, and the volume of each gas filling chamber 69, 71 is large, so that the gas pressure is low and pulsation can be effectively reduced with respect to the low set pressure. As in the first embodiment, pulsation can be effectively reduced for a wide set pressure.

In the embodiment shown in FIG. 4, in the circuit constituting the fuel injection device 91, the fuel supplied from the low pressure pump 93 is discharged by the high pressure pump 95, and the fuel is accumulated by the common rail 97. It is configured to discharge. In FIG. 4, 101 is a fuel tank, 103 is a low-pressure regulator valve, and 105 is an air vent valve. In this embodiment, first and second pulsation reduction dampers 107 and 109 having different characteristics are provided. The first pulsation reduction damper 107 is mounted on a high-pressure pump, and the second pulsation reduction damper 109 is a common rail. 97. The first pulsation reduction damper 107 is filled with a high-pressure gas, and the second pulsation reduction damper 109 is filled with a low-pressure gas. These pulsation reduction dampers are configured such that different gas pressures are sealed in the respective gas sealing chambers, and each diaphragm is supported at a different gas pressure.

The embodiment shown in FIG. 4 also includes two partitions having different pulsation reduction characteristics, so that pulsation can be effectively reduced for a wide range of set pressures.

The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention. For example, the diaphragm-type damper according to the present invention has been described using a pulsation damper for high-pressure fuel as an example. However, the invention is not limited thereto, and may be used for a low-pressure damper. The same effect can be obtained not only with the fuel injection pump but also with a damper used for a hydraulic circuit, a water pipe, or the like.

In the second embodiment, the two pulsation reduction characteristics are made different by changing the volume of the two gas filling chambers. However, the present invention is not limited to this. Similar effects can be obtained even if different.

[0041]

According to the first aspect of the present invention, a plurality of flexible partition walls having different pulsation reduction characteristics are provided.
Further, since these flexible partitions act on a common pressure receiving chamber, the pressure pulsation can be reduced for a wide range of fluid pressure. In particular, pulsation can be effectively reduced at a variable fuel pressure. Moreover, since the damper is a gas-filled damper, the structure is easy.

According to the second aspect of the present invention, in each of the gas-filled chambers, one of the gas pressure and the volume of the gas-filled chamber is made different, so that the flexible space supported by the gas in the gas chambers. The pulsation reduction characteristics of the conductive partition can be made different with a simple configuration. In addition, since the gas pressure and the volume need only be changed, the pulsation reduction characteristics of each flexible partition can be easily made different, and the pulsation reduction characteristics can be easily set to arbitrary characteristics.

According to the third aspect of the present invention, since the pressure receiving areas of the flexible partitions are made different in each gas filled chamber, it is easy to make the pulsation reduction characteristics of each flexible partition different. In addition, the pulsation reduction characteristics can be easily set to arbitrary characteristics.

According to the fourth aspect of the present invention, since the gas-filled chambers communicate with each other, at least one of the capacity of the gas-filled chamber and the pressure-receiving area of the flexible partition wall is made different, so that a simple configuration is achieved. Thus, the pulsation reduction characteristics of each flexible partition can be easily changed.

[0045]

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection pump equipped with a pulsation reducing damper according to an embodiment of the present invention.

FIG. 2 is a graph showing the effect of the pulsation reducing damper according to the embodiment of the present invention as compared with the conventional example.

FIG. 3 is a sectional view of a pulsation reducing damper according to another embodiment.

FIG. 4 is a circuit diagram of a fuel injection device according to another embodiment.

[Explanation of symbols]

 39 High-pressure damper (pulsation reduction damper) 41 Case 47, 69 First gas-filled chamber 49 First diaphragm (flexible partition) 55, 71 Second gas-filled chamber 53 Second diaphragm (flexible partition) 59 Pressure-receiving chamber 73 Gas filled chamber communication passage (communication passage)

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Toshio Aoki 3-13-26 Yayumicho, Higashimatsuyama City, Saitama Prefecture Inside of Zexel Higashimatsuyama Plant

Claims (4)

[Claims] 1. A pulsation reducing damper comprising: a plurality of gas-filled chambers; a plurality of flexible partitions supported by gas pressures of the respective gas-filled chambers; and a common pressure-receiving chamber for applying a fluid pressure to each partition. The pulsation reducing damper, wherein the plurality of flexible partition walls have different pulsation reducing characteristics. 2. The pulsation reducing damper according to claim 1, wherein at least one of the gas pressure and the volume of the gas-filled chamber of each gas-filled chamber is different for each gas-filled chamber. 3. The pressure receiving area of a flexible partition provided in the gas filling chamber is made different.
2. The pulsation reducing damper according to item 1. 4. The plurality of gas-filled chambers are communicated with each other, and at least one of the volume of each gas-filled chamber and the pressure receiving area of a flexible partition is different for each gas-filled chamber. The pulsation reduction damper according to claim 1, wherein: