Field of the Invention
The present invention relates to a delivery pipe (an injection
pipe) of an internal combustion engine of a vehicle.
Background of the Invention
In order to obtain a stable fuel injection in a multi-cylinder
internal combustion engine, a fuel pressure pulsation caused due to fuel injection
is desired to be decreased.
Japanese Patent Publication 2002-339835
discloses a conventional delivery pipe including a double pipe structure
with an inner pipe and an outer pipe for decreasing a fuel pressure pulsation. When
receiving a fuel pressure pulsation, the inner pipe vibrates to be elastically deformed
thereby decreasing the fuel pressure pulsation. When the inner pipe vibrates, air
inside the inner pipe oscillates in pressure to cause a noise which is emitted from
the inner pipe. However, no countermeasure has been taken to suppress the noise.
Summary of the Invention
An object of the present invention is to provide a delivery
pipe capable of suppressing a noise emitted from the delivery pipe.
A delivery pipe according to an embodiment of the present
invention that achieves the above and other objects is described as follows:
- (1) A delivery pipe according to the present invention includes an outer pipe,
an inner pipe, and a noise emission decreasing device.
The outer pipe is connected to a plurality of fuel injectors of a multi-cylinder
internal combustion engine.
The inner pipe is disposed in the outer pipe and has an open end through which an
interior of the inner pipe communicates with atmosphere. When a wall of the inner
pipe vibrates, a pressure of an interior of the inner pipe oscillates.
The noise emission decreasing device acts so as to decrease a noise emitted from
the inner pipe.
- (2) The noise emission decreasing device includes a mesh.
- (3) The noise emission decreasing device includes a porous member.
- (4) The noise emission decreasing device includes a vibration suppressing member
provided to the inner pipe.
- (5) The noise emission decreasing device includes an elastic tube fitted into
the inner pipe.
- (6) The noise emission decreasing device includes a wire harness inserted into
the inner pipe.
- (7) The noise emission decreasing device is provided at all portions of a cross
section of an interior of the inner pipe.
- (8) The noise emission decreasing device is provided at only a portion of a
cross section of an interior of the inner pipe.
- (9) The noise emission decreasing device is disposed at an entire circumference
of an inside surface of the inner pipe.
- (10) The noise emission decreasing device is disposed at only a portion of a
circumference of an inside surface of the inner pipe.
- (11) The noise emission decreasing device is disposed at only the open end of
the inner pipe.
- (12) The noise emission decreasing device is disposed at only a longitudinally
intermediate portion of the inner pipe.
- (13) The noise emission decreasing device is pressed into the inner pipe and
is located inside the inner pipe.
- (14) The noise emission decreasing device is bonded to an inner surface of the
inner pipe and is located inside the inner pipe.
- (15) The noise emission decreasing device includes a vibration damping sheet
attached to an inner surface of the inner pipe.
- (16) The noise emission decreasing device includes a vibration damping coating
coated to an inner surface of the inner pipe.
- (17) The inner pipe includes a main pipe and a branch pipe diverging from the
main pipe and extending toward the fuel injector and the wire harness extends through
the inner pipe to a respective fuel injector.
Technical advantages of the present invention are as follows:
According to the delivery pipe of item (1) above, since
the delivery pipe is provided with the inner pipe and has a double pipe structure,
the inner pipe can decrease a fuel pressure pulsation of fuel between the outer
pipe and the inner pipe by being deformed when receiving the pressure pulsation.
Further, since the delivery pipe includes the noise emission
decreasing device, the noise emission decreasing device suppresses a pressure oscillation
of the interior of the inner pipe thereby decreasing a noise generated due to the
pressure oscillation of the interior of the inner pipe and radiated from the inner
pipe.
According to the delivery pipe of item (2) above, since
the noise emission decreasing device includes a mesh, when an air vibration generated
inside the inner pipe passes through the mesh, the energy of the pressure of the
air vibration is absorbed by the mesh and is dispersed over the area of the mesh,
whereby a noise of the air vibration is decreased.
According to the delivery pipe of item (3) above, since
the noise emission decreasing device includes a porous member, when an air vibration
generated inside the inner pipe passes through the porous member, the energy of
the pressure of the air vibration is absorbed by the porous member and is dispersed
over all portions of the porous member, whereby a noise of the air vibration is
decreased.
According to the delivery pipe of item (4) above, since
the noise emission decreasing device includes a vibration suppressing member provided
to the inner pipe, vibration of the inner pipe can be damped by the vibration suppressing
member accompanied by vibration damping of the interior of the inner pipe, whereby
a noise from the delivery pipe is decreased.
According to the delivery pipe of item (5) above, since
the noise emission decreasing device includes an elastic tube fitted into the inner
pipe, vibration of the inner pipe can be damped by the elastic tube accompanied
by vibration damping of the interior of the inner pipe, whereby a radiation noise
from the delivery pipe is decreased.
According to the delivery pipe of item (6) above, since
the wire harness is inserted into the inner pipe, an open portion of the cross section
of the inner pipe, that is, a portion of the section which is not occupied by the
inserted wire harness, is decreased so that emission of a noise passing through
the open portion of the cross section is decreased. Further, since a space within
the inner pipe is used for mounting the wire harness, a space required for mounting
the wire harness which conventionally has been provided outside the delivery pipe
can be reduced.
According to the delivery pipe of item (7) above, since
the noise emission decreasing device is provided at all portions of the cross section
of the interior of the inner pipe, a pressure oscillation of the interior of the
inner pipe can be effectively decreased.
According to the delivery pipe of item (8) above, since
the noise emission decreasing device is provided at only a portion of the cross
section of the interior of the inner pipe, the noise emission decreasing device
can be decreased in cost compared with the case of item (7) above.
According to the delivery pipe of item (9) above, since
the noise emission decreasing device is provided at an entire circumference of an
inside surface of the inner pipe, a pressure oscillation of the interior of the
inner pipe can be effectively decreased.
According to the delivery pipe of item (10) above, since
the noise emission decreasing device is provided at only a portion of a circumference
of an inside surface of the inner pipe, the noise emission decreasing device can
be decreased in cost compared with the case of item (9) above.
According to the delivery pipe of item (11) above or item
(12) above, since the noise emission decreasing device is provided locally in a
longitudinal direction of the inner pipe, the noise emission decreasing device can
be decreased in cost compared with a case where the noise emission decreasing device
is provided at all portions of the inner pipe in the longitudinal direction of the
inner pipe.
According to the delivery pipe of item (13) above, since
the noise emission decreasing device is pressed into the inner pipe, the inner pipe
is pretensioned by the noise emission decreasing device. Due to the pretension,
the inner pipe can better endure the compression load from the fuel. Further, since
the noise emission decreasing device is located inside the inner pipe, a space for
mounting the delivery pipe is not increased in spite of mounting the noise emission
decreasing device.
According to the delivery pipe of item (14) above, since
the noise emission decreasing device is located inside the inner pipe, a space for
mounting the delivery pipe is not increased in spite of mounting the noise emission
decreasing device.
According to the delivery pipe of item (15) above, since
the noise emission decreasing device includes a vibration damping sheet attached
to an inner surface of the inner pipe, vibration of the inner pipe can be damped
by the vibration damping sheet accompanied by vibration damping of the interior
of the inner pipe, whereby a noise from the delivery pipe is decreased.
According to the delivery pipe of item (16) above, since
the noise emission decreasing device includes a vibration damping coating coated
to an inner surface of the inner pipe, vibration of the inner pipe can be damped
by the vibration damping coating accompanied by vibration damping of the interior
of the inner pipe, whereby a noise from the delivery pipe is decreased.
According to the delivery pipe of item (17) above, since
the inner pipe includes the branch pipe, by changing a position and a cross section
of the branch pipe, a vibration pattern of the inner pipe and a columnar vibration
pattern and a resonance frequency of the interior of the inner pipe can be changed
or controlled, whereby a noise from the delivery pipe is decreased.
Brief Description of the Drawings
The delivery pipe of the various embodiments of the present
invention will now be explained with reference to the accompanying drawings, in
which:
- FIG. 1 is a front elevational view of a delivery pipe according to a first embodiment
of the present invention;
- FIG. 2 is a side elevational view of the delivery pipe according to the first
embodiment of the present invention;
- FIG. 3 is a front elevational view of a delivery pipe according to a second
embodiment of the present invention;
- FIG. 4 is a front elevational view of a delivery pipe according to a third embodiment
of the present invention;
- FIG. 5 is a side elevational view of a delivery pipe according to a fourth embodiment
of the present invention; and
- FIG. 6 is a front elevational view of a delivery pipe according to a fifth embodiment
of the present invention.
Detailed Description of Preferred Embodiments
Several embodiments of the present invention will be explained.
Portions generic (common or similar) throughout all of the embodiments of the invention
are denoted with the same reference numerals throughout all of the embodiments of
the invention.
First, portions generic throughout all of the embodiments
of the invention will be explained with reference to FIGs. 1 and 2.
A delivery pipe 10 according to the present invention includes
an outer pipe 20, an inner pipe 30, and a noise emission decreasing device 40 for
decreasing a noise emitted from the inner pipe 30. The outer pipe 20 is connected
to a plurality of fuel injectors 1 of a multi-cylinder internal combustion engine.
The inner pipe 30 is disposed in the outer pipe 20 and has an open end through which
an interior of the inner pipe communicates with atmosphere at at least one end of
the inner pipe 30. When a wall of the inner pipe 30 vibrates, a pressure of an interior
of the inner pipe 30 oscillates. The noise emission decreasing device 40 acts so
as to decrease oscillation of the pressure of the interior of the inner pipe 30.
The delivery pipe 10 has a double pipe structure having the outer pipe 20 and the
inner pipe 30.
The outer pipe 20 and the inner pipe 30 define a fuel passage
22 therebetween through which fuel flows and is delivered to respective fuel injectors
1. The outer pipe 20 is made from, for example, synthetic resin or metal. The outer
pipe 20 is connected to the same number of injection passages 23 as the number of
the injectors 1 connected to the outer pipe 20 and has a connector 21 at a longitudinal
end of the outer pipe 20. As illustrated by arrow A in FIGs. 1, 3, 4 and 6, the
fuel flows through the connector 21 into the fuel passage 22 and flows from the
fuel passage 22 to the injection passages 23. The fuel injectors 1 inject fuel in
a predetermined injection order.
The inner pipe 30 extends in the outer pipe 20 in a longitudinal
direction of the outer pipe 20. The inner pipe 30 is made from, for example, synthetic
resin or metal. The inner pipe 30 is fixed to the outer pipe 20 at end plates 24
of the outer pipe 20. End portions of the inner pipe 30 may extend through the end
plates 24 of the outer pipe 20. If, for example, both of the outer pipe 20 and the
inner pipe 30 are made from metal, the inner pipe 30 may be fixed to the end plates
24 of the outer pipe 20 by welding. The interior of the inner pipe 30 is fluidly
separated from the fuel passage 22.
Preferably, the inner pipe 30 has a wall thickness smaller
than a wall thickness of the outer pipe 20. Preferably, the inner pipe 30 has a
substantially rectangular cross section so that a wall of the inner pipe 30 has
a flat portion 33. When a fuel pressure acts on the wall of the inner pipe 30, the
inner pipe 30 can be deformed relatively easily at the flat portion 33 in a direction
perpendicular to a longitudinal direction of the inner pipe 30. By the deformation,
the inner pipe 30 absorbs a pressure pulsation generated in the fuel at the time
of fuel injection.
At least one longitudinal end 31 of the inner pipe 30 is
open so that the interior of the inner pipe 30 communicates with the atmosphere
through the open end 31. In the embodiment shown, the inner pipe 30 has opposite
open ends. The open end 31 may be open at an entire transverse cross section of
the inner pipe or at only a portion of the transverse cross section of the inner
pipe.
The noise emission decreasing device 40 is a device for
absorbing and dispersing a vibration of the interior of the inner pipe 30 generated
when the wall of the inner pipe 30 vibrates and is alternately deformed thereby
decreasing a noise emitted from the open end 31 of the inner pipe 30. The noise
emission decreasing device 40 may be any one of a mesh (mesh member) 41 provided
in or to the inner pipe 30, (or as shown in FIGs. 2-6) (b) a porous member 42 provided
in or to the inner pipe 30, (c) a vibration damping member 43 provided in or to
the inner pipe 30, (d) an elastic member 44 provided in or to the inner pipe 30,
and (e) a wire harness 45 inserted in the inner pipe 30 so as to extend through
the inner pipe 30.
Technical effects and advantages of the portions generic
to all of the embodiments of the present invention will now be explained.
Since the delivery pipe according to the present invention
has a double pipe structure including the outer pipe 20 and the inner pipe 30, the
pressure vibration of the fuel flowing in the fuel passage between the outer pipe
20 and the inner pipe 30 is effectively decreased by the inner pipe 30 being deformed.
Though a noise or vibration of the interior (air) of the inner pipe 30 is likely
to be emitted to the environment because the at least one end of the inner pipe
30 is an open end, the noise emitted from the inner pipe 30 (a part of an engine
noise) can be effectively decreased by the noise emission decreasing device 40 provided
in or to the inner pipe 30.
Since the inner pipe 30 has an open end at at least one
end of the inner pipe, a breakage and/or a permanent deformation of the inner pipe
30, which is likely to occur due to a welding heat if opposite ends of the inner
pipe are closed and the inner pipe and the outer pipe are welded to each other,
will be prevented.
Next, portions unique to each embodiment of the present
invention will be explained.
[Embodiment 1] (FIGs. 1 and 2)
In Embodiment 1 of the present invention, the noise emission
decreasing device 40 includes a mesh (mesh member) 41 provided in or to the inner
pipe 30. The inner pipe 30 has a simple structure as a pipe. The mesh 41 is made
from, for example, synthetic resin or metal. The mesh has a relatively fine mesh
structure. The mesh 41 may, for example, be coupled or fixed to the inner pipe 30
in the same manner as a cap is coupled or fixed to a pipe, may be pressed into the
inner pipe 30, or may be bonded to an inner surface of the inner pipe 30.
The mesh 41 may be disposed at the open end 31 of the inner
pipe 30 or at a place other than the open end, for example, at a longitudinally
intermediate portion of the inner pipe 30. In FIG. 1, the mesh 41 is disposed at
the open end 31. When the inner pipe 30 has opposite open ends 31, the mesh 41 may
be disposed at both of the open ends 31 or at one of the open ends 31.
The mesh 41 may be disposed at all portions of a cross
section of an interior of the inner pipe 30 or at only a portion of a cross section
of an interior of the inner pipe 30.
In Embodiment 1 of the present invention, the following
technical advantages are further obtained:
Since the noise emission decreasing device 40 includes
the mesh 41, when the air vibration generated inside the inner pipe 30 passes through
the mesh 41, an energy of the vibration is absorbed and dispersed by the mesh 41,
whereby the noise emitted from the delivery pipe 10 is effectively decreased.
When the mesh 41 is pressed into the inner pipe 30, a pretension
is generated in the inner pipe 30. As a result, the inner pipe 30 can better endure
the compression loaded on the inner pipe 30 from the fuel between the outer pipe
20 and the inner pipe 30.
Further, since the mesh 41 is located in the inner pipe
30, a space required for mounting the delivery pipe 10 is not increased despite
provision of the mesh 41.
Furthermore, since the inner pipe 30 has a simple structure,
a cost for manufacturing the delivery pipe 10 is low.
[Embodiment 2] (FIG. 3)
In Embodiment 2 of the present invention, the noise emission
decreasing device 40 includes a porous member 42 provided in or to the inner pipe
30. The inner pipe 30 has a simple structure as a pipe. The porous member 42 is
made from, for example, sponge. The porous member 42 may, for example, be pressed
into the inner pipe 30, may be inserted into the inner pipe 30, or may be fixed
to an inside surface of the inner pipe 30 by an adhesive.
The porous member 42 may be disposed at only the open end
31 of the inner pipe 30 and the vicinity thereof, or may be disposed at a longitudinally
intermediate portion of the inner pipe 30, or may be disposed at all portions of
the inner pipe in the longitudinal direction of the inner pipe 30. In FIG. 3, the
porous member 42 is located at the longitudinal end of the inner pipe 30 and the
vicinity thereof. When the inner pipe 30 has opposite open ends 31, the porous member
42 may be at both ends 31 or may be at only one end 31. The porous member 42 may
be provided at all portions of a cross section of the interior of the inner pipe
30 or may be provided at only a portion of a cross section of the interior of the
inner pipe 30.
In Embodiment 2 of the present invention, the following
technical advantages are further obtained:
Since the noise emission decreasing device 40 includes
the porous member 42, when the air vibration generated inside the inner pipe 30
passes through the porous member 42, an energy of the vibration is absorbed and
dispersed by the porous member 42, whereby the noise emitted from the delivery pipe
10 is effectively decreased.
When the porous member 42 is pressed into the inner pipe
30, a pretension is generated in the inner pipe 30. As a result, the inner pipe
30 can better endure the compression loaded on the inner pipe 30 from the fuel between
the outer pipe 20 and the inner pipe 30.
Further, since the porous member 42 is located in the inner pipe 30, a space required
for mounting the delivery pipe 10 is not increased despite provision of the porous
member 42.
Furthermore, since the inner pipe 30 has a simple structure,
a cost for manufacturing the delivery pipe 10 is low.
[Embodiment 3] (FIG. 4)
In Embodiment 3 of the present invention, the noise emission
decreasing device 40 includes a vibration damping member 43 provided in or to the
inner pipe 30. The inner pipe 30 has a simple structure as a pipe. The vibration
damping member 43 includes a vibration damping sheet or a vibration damping coating.
The vibration damping member 43 may be attached (for example, fixed by bonding)
or coated to an inside surface of the inner pipe 30.
The vibration damping member 43 may be disposed at only
the open end 31 of the inner pipe 30 and the vicinity thereof, or may be disposed
at a longitudinally intermediate portion of the inner pipe 30, or may be disposed
at all portions of the inner pipe in the longitudinal direction of the inner pipe
30. In FIG. 4, the vibration damping member 43 is located at all portions of the
inner pipe in the longitudinal direction of the inner pipe 30. When the inner pipe
30 has opposite open ends 31, the vibration damping member 43 may be at both ends
31 or may be at only one end 31. The vibration damping member 43 may be disposed
at an entire circumference of an inside surface of the inner pipe 30 or may be disposed
at an inside surface of only a portion of a circumference of the inner pipe 30.
In Embodiment 3 of the present invention, the following
technical advantages are further obtained:
Since the noise emission decreasing device 40 includes
the vibration damping member 43, the vibration damping member 43 damps vibration
of a wall of the inner pipe 30 and decreases an energy of vibration of the inner
pipe 30 itself, whereby the noise emitted from the inner pipe 30 is effectively
decreased.
When the vibration damping member 43 is attached or coated
to the inside surface of the inner pipe 30, the vibration damping member 43 does
not protrude out from the delivery pipe 10. As a result, a space required for mounting
the delivery pipe 10 is not increased despite provision of the vibration damping
member 43.
Furthermore, since the inner pipe 30 has a simple structure,
a cost for manufacturing the delivery pipe 10 is low.
[Embodiment 4] (FIG. 5)
In Embodiment 4 of the present invention, the noise emission
decreasing device 40 includes an elastic member 44 provided in or to the inner pipe
30. The inner pipe 30 has a simple structure as a pipe. The elastic member 44 includes,
for example, a tube made from rubber. The elastic member 44 may be pushed into the
inner pipe 30. The elastic member 44 may be fixed to the inside surface of the inner
pipe 30 by, for example, an adhesive. The elastic member 44 contacts the inside
surface of the inner pipe 30.
The elastic member 44 may be disposed at only the open
end 31 of the inner pipe 30 and the vicinity thereof, or may be disposed at a longitudinally
intermediate portion of the inner pipe 30, or may be disposed at all portions of
the inner pipe in the longitudinal direction of the inner pipe 30. When the inner
pipe 30 has opposite open ends 31, the elastic member 44 may be at both ends 31
or may be at only one end 31. The elastic member 44 may be disposed at an entire
circumference of an inside surface of the inner pipe 30 or may be disposed at an
inside surface of only a portion of a circumference of the inner pipe 30.
In Embodiment 4 of the present invention, the following
technical advantages are further obtained:
Since the noise emission decreasing device 40 includes
the elastic member 44, the elastic member 44 damps vibration of a wall of the inner
pipe 30 and decreases an energy of vibration of the inner pipe 30 itself, whereby
the noise emitted from the inner pipe 30 is effectively decreased.
When the elastic member 44 is pressed into the inner pipe
30, a pretension is generated in the inner pipe 30. As a result, the inner pipe
30 can better endure the compression loaded on the inner pipe 30 from the fuel between
the outer pipe 20 and the inner pipe 30. Further, since the elastic member 44 does
not protrude out from the delivery pipe 10, a space required for mounting the delivery
pipe 10 is not increased despite provision of the elastic member 44.
Furthermore, since the inner pipe 30 has a simple structure,
a cost for manufacturing the delivery pipe 10 is low.
[Embodiment 5] (FIG. 6)
In Embodiment 5 of the present invention, the noise emission
decreasing device 40 includes a wire harness 45 provided in the inner pipe 30 so
as to extend through the inner pipe 30.
The inner pipe 30 includes a main pipe 34 and a plurality
of branch pipes 32 diverging from the main pipe 34 and extending toward the fuel
injector 1 and the wire harness 45 extends through the inner pipe 30 to a respective
fuel injector 1. The number of the branch pipes 32 may be equal to the number of
the injectors 1 or may be smaller than the number of the injectors 1.
The wire harness 45 is a wire harness connected to the
injectors 1. The wire harness 45 extends into the inner pipe 30 through the open
end 31 of the inner pipe 30 and is bent at respective branch pipes 32 to extend
through the branch pipes 32 to the respective injectors 1.
In Embodiment 5 of the present invention, the following
technical advantages are further obtained:
Since the wire harness 45 extends through the inner pipe
30, a cross section of the interior of the inner pipe 30 through which a noise generated
in the inner pipe is emitted to the environment is reduced, whereby the noise emitted
from the inner pipe 30 is effectively decreased.
Further, since the interior of the inner pipe 30 is utilized
as a space for disposing the wire harness 45, the wire harness mounting space is
reduced compared with a conventional case where a wire harness is disposed outside
the delivery pipe 10.
Further, the branch pipe 32 acts as a breathing hole and
the branch pipe 32 changes a rigidity of the inner pipe 32. By changing a position
in the longitudinal direction of the inner pipe 30 and a cross section of the branch
pipe 32, a vibration pattern of the inner pipe 30 and a columnar vibration pattern
and a resonance frequency of the interior of the inner pipe 30 can be changed or
controlled, whereby a noise from the delivery pipe is decreased.
The wire harness 45 may be a wire harness connected to
parts other than the injector 1.
Several embodiments of the present invention are specifically
illustrated and/or described herein. However, it will be appreciated that modifications
and variations of the present invention are covered by the above teachings and within
the purview of the appended claims without departing from the sprit and intended
scope of the invention.
