Fluid handling – Line condition change responsive valves – With separate connected fluid reactor surface
Reexamination Certificate
2002-01-15
2004-06-22
Hepperle, S (Department: 3753)
Fluid handling
Line condition change responsive valves
With separate connected fluid reactor surface
C251S118000, C123S459000
Reexamination Certificate
active
06752170
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel pressure regulating valve provided with a means for reducing a noise.
2. Description of the Related Art
In a motor car in recent years, a quiet property becomes important, and in accordance with a progress of the quiet property, a noise generated in the fuel pressure regulating valve generates a problem as a new noise source.
A conventional fuel pressure regulating valve is generally structured, as shown in
FIG. 17
, such that a fuel chamber
12
into which a fuel discharged from a fuel pump flows from an inlet port
11
and a spring chamber
14
receiving a spring
13
are formed within a housing
10
so as to be separated by a diaphragm
15
, a tubular bush
16
flowing out the fuel within the fuel chamber
12
is provided, a valve body
17
mounted to the diaphragm
15
is opposed to a valve seat
18
formed in a peripheral edge of an opening portion of the bush
16
, and the valve body
17
is energized in a direction of the valve seat
18
(in a valve closing direction) by the spring
13
.
The fuel pressure regulating valve is structured such that when a force in a valve opening direction due to a fuel pressure within the fuel chamber
12
and a force (a set pressure) in the valve closing direction generated by the spring
13
are applied to the valve body
17
(the diaphragm
15
), and the force in the valve opening direction due to the fuel pressure within the fuel chamber
12
becomes greater than the force in the valve closing direction generated by the spring
13
, the valve body
17
is pressed up in the valve opening direction due to the fuel pressure to a position at which both of the forces balance. Accordingly, an annular gap is formed between the valve body
17
and the valve seat
18
, and the fuel within the fuel chamber
12
flows toward a central direction of the opening portion of the bush
16
from respective portions in the annular gap so as to be returned within a fuel tank from a outflow port
19
in the housing
10
.
In the conventional fuel pressure regulating valve mentioned above, since the fuel within the fuel chamber
12
flows with great force toward the central direction of the opening portion in the bush
16
from the respective portions in the annular gap formed between the valve body
17
and the valve seat
18
, the fuel flowing with great force from the respective portions in the annular gap collides in the center portion of the opening portion in the bush
16
, a pressure in the collision portion increases so as to become a positive pressure, and the positive pressure is applied to a center portion on a lower surface of the valve body
17
. Further, near an inner peripheral surface of the opening portion in the bush
16
, since the fuel flows with great force toward the center direction of the opening portion in the bush
16
, a peel-off of the fuel flow is generated so as to generate a negative pressure, and the negative pressure is applied to the lower surface of the valve body
17
.
Since during driving an engine, a fuel consumption varies every second in correspondence to a driving state, a lift amount of the valve body
17
(a gap size between the valve body
17
and the valve seat
18
) varies every second in correspondence thereto, and a flow amount of the fuel flowing from the gap between the valve body
17
and the valve seat
18
toward the central direction of the opening portion in the bush
16
varies every second, the positive pressure and the negative pressure which are generated near the lower surface of the valve body
17
pulsate, and there occurs a phenomenon that the valve body
17
and the diaphragm
15
vibrate due to a pressure pulsation. Accordingly, the spring
13
resonates so as to generate the noise, and the vibration of the fuel pressure regulating valve is transmitted to a fuel pipe and a fuel tank so as to resonate them, thereby increasing the noise.
Further, there is a case that the noise is generated due to the pulsation resonation with respect to the equipment arranged in a downstream side of the outflow port
19
.
That is, a pressure distribution of the fuel in the opening portion of the bush is structured such that the center portion has the positive pressure and the portion near the inner peripheral surface has the negative pressure as mentioned above. That is, the pressure distribution is uneven. When the fuel having the uneven pressure distribution flows into the equipment arranged in the downstream side of the outflow port
19
, for example, a jet pump, a fuel pipe and the like, these equipment vibrate due to an influence of the pressure distribution. As a result, the pulsation resonance is generated between the equipment and the fuel pressure regulating valve, and the noise is also generated due to this noise.
In this case, a fuel pressure regulating valve for reducing the noise mentioned above is introduced in Japanese National Publication of Translated Version No. 11-501388. The fuel pressure regulating valve is provided with a step having a diameter reduced toward a downstream side, in an inner peripheral side of a bush. That is, a large diameter portion and a small diameter portion are respectively arranged in an upstream side and a downstream side on the boundary of the step. Then, the sound is reduced by making sized such as a diameter, a cross sectional area, a length and the like in the large diameter portion and the small diameter portion proper, in other words, making a throttling amount of the flow in the small diameter portion proper.
However, the size of the fuel pressure regulating valve in the publication is set on the assumption that a flow amount of a fuel passing through an inner portion of the bush exists within a specified range. The flow amount of the fuel passing through the inner portion of the bush varies every second in correspondence to a drive condition or the like. Accordingly, the fuel pressure regulating valve in the publication mentioned above is effective in the case that the fuel flow amount exists within the specific range, however, it is difficult to say that the fuel pressure regulating valve is effective in every fuel flow amount.
Further, at a time when the fuel flows into the bush from a gap between a valve body and a valve seat at a high speed, there is a case that there occurs a so-called reduced pressure boiling in which a negative pressure area appears due to a flow speed difference and a bubble cell nucleus is generated within the fuel. The generated bubble cell nucleus expands in the negative pressure area within the bush so as to be burst. A pressure wave generated due to the burst plays a role in generating the noise.
In this case, a fuel pressure control valve for reducing the noise due to the reduced pressure boiling is introduced in Japanese Unexamined Patent Publication No. 12-104642. The fuel pressure regulating valve is structured such that an introduction port communicated with a fuel tank is pierced in a return pipe connected to a downstream side of a bush. In this fuel pressure regulating valve, generation of a negative pressure area is restricted by introducing an ambient atmosphere within the fuel tank which is under a substantially atmospheric pressure, from the introduction port. Then, the burst of the bubble cell nucleus generated due to the reduced pressure boiling is restricted and the noise is reduced.
However, the fuel pressure regulating valve in the publication mentioned above achieves its effect only after being connected to the return pipe. That is, unless the fuel pressure regulating valve is connected to the return pipe, it is impossible to reduce the noise.
SUMMARY OF THE INVENTION
The present invention is made by taking the matters mentioned above into consideration, and an object of the present invention is to provide a fuel pressure regulating valve which can effectively reduce a noise without relation to a flow amount of a fuel.
In order to achieve the object mentioned above, a fuel pressure regulating valve in accordance with th
Furukawa Takashi
Muramatsu Toshihiko
Takase Shinji
Denso Corporation
Hepperle S
Nixon & Vanderhye PC
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