U.S. patent application number 15/050498 was filed with the patent office on 2016-08-25 for pump with quick discharge function.
The applicant listed for this patent is Faurecia Systemes D'Echappement. Invention is credited to Frederic Greber, Boris Kienle.
Application Number | 20160245268 15/050498 |
Document ID | / |
Family ID | 52829192 |
Filed Date | 2016-08-25 |
United States Patent
Application |
20160245268 |
Kind Code |
A1 |
Greber; Frederic ; et
al. |
August 25, 2016 |
PUMP WITH QUICK DISCHARGE FUNCTION
Abstract
A pump includes a chamber defined by a piston movable in a body
comprising an intake opening able to communicate with the chamber
and a first non-return member authorizing passage of fluid from the
opening toward the chamber, and prohibiting the passage from the
chamber toward the opening. An expulsion opening is between the
chamber and a duct, and a second non-return member authorizes
passage of fluid from the chamber toward the duct, and prohibits
passage from the duct toward the chamber. The body includes a
discharge opening communicating with the duct and able to
communicate with the opening, and a third non-return member movable
between an open position, in which the duct communicates with the
opening, and a closed position prohibiting the passage of fluid
between the duct and the opening. The pump includes a member to
move the third non-return member.
Inventors: |
Greber; Frederic; (Ecot,
FR) ; Kienle; Boris; (Biberbach, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Faurecia Systemes D'Echappement |
Nanterre |
|
FR |
|
|
Family ID: |
52829192 |
Appl. No.: |
15/050498 |
Filed: |
February 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01K 23/065 20130101;
F01K 9/003 20130101; F04B 49/035 20130101; F04B 39/123 20130101;
F04B 7/0266 20130101; F04B 35/045 20130101; F04B 17/03
20130101 |
International
Class: |
F04B 17/03 20060101
F04B017/03; F01K 9/00 20060101 F01K009/00; F04B 7/02 20060101
F04B007/02; F01K 23/06 20060101 F01K023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 25, 2015 |
FR |
1551595 |
Claims
1. A pump including a hollow body and a piston housed in the hollow
body movably in a longitudinal direction, the piston defining, with
the hollow body, a compression chamber with a variable volume
depending on a position of the piston in the longitudinal
direction, the hollow body including: an intake opening designed to
communicate with a fluid source and able to communicate with the
compression chamber; a first non-return member arranged between the
intake opening and the compression chamber to allow the passage of
fluid from the intake opening to the compression chamber, and to
prohibit the passage of fluid from the compression chamber to the
intake chamber; an expulsion opening emerging in the compression
chamber and communicating with an expulsion duct; a second
non-return member arranged between the compression chamber and the
expulsion duct to allow the passage of fluid from compression
chamber to the expulsion duct, and to prohibit the passage of fluid
from the expulsion duct to the compression chamber; and wherein:
the hollow body includes a discharge opening communicating with the
expulsion duct and able to communicate with the intake opening, and
a third non-return member movable between an open position, in
which the expulsion duct communicates with the intake opening, and
a closed position prohibiting the passage of fluid between the
expulsion duct and the intake opening, and the pump includes
displacement elements for moving the third non-return member.
2. The pump according to claim 1, wherein the displacement elements
include: a ferromagnetic element movable between a first position,
in which the third non-return member is in the open position, and a
second position, in which the third non-return member is in the
closed position, a first elastic member biasing the ferromagnetic
element toward its first position, and an electric coil,
surrounding the ferromagnetic element and electrically connected to
a power supplier able to apply an adjustable current, wherein a
position of the ferromagnetic element depends on voltage of the
current.
3. The pump according to claim 2, wherein: the third non-return
member includes a non-return gate biased in the closed position by
a third elastic member, and the displacement elements include an
actuating element secured to the piston and designed to cooperate
with the non-return gate to move the non-return gate into the open
position by pushing the non-return gate against the biasing of the
third elastic member, and when the piston is in a predetermined
discharge position, said ferromagnetic element is formed by a rod
secured to the piston.
4. The pump according to claim 3, wherein the piston is movable, in
the longitudinal direction, between: a first extreme position, in
which the actuating element cooperates with the non-return gate,
and in which the volume of the compression chamber is maximal, a
second extreme position, in which the volume of the compression
chamber is minimal, and at least one intermediate position, in
which the actuating element is kept at a distance from the
non-return gate.
5. The pump according to claim 2, wherein the third non-return
member includes a non-return gate, said ferromagnetic element being
formed by the non-return gate.
6. The pump according to claim 1, wherein the piston includes a rod
made from a ferromagnetic material and extending in the
longitudinal direction, the pump including an electric coil
surrounding the rod of the piston and electrically connected to a
power supplier able to apply a variable electric current, wherein a
position of the piston depends on voltage of the electric
current.
7. The pump according to claim 1, wherein the intake opening
includes a filter.
8. The pump according to claim 1, including a variable volume fluid
reservoir forming the fluid source.
9. The pump according to claim 1, wherein the fluid is gas, in
particular air.
10. An assembly of a pump and a pressure-sensitive controllable
element controlled by the pump, wherein the pump includes a hollow
body and a piston housed in the hollow body movably in a
longitudinal direction, the piston defining, with the hollow body,
a compression chamber with a variable volume depending on a
position of the piston in the longitudinal direction, the hollow
body including: an intake opening designed to communicate with a
fluid source and able to communicate with the compression chamber;
a first non-return member arranged between the intake opening and
the compression chamber to allow the passage of fluid from the
intake opening to the compression chamber, and to prohibit the
passage of fluid from the compression chamber to the intake
chamber; an expulsion opening emerging in the compression chamber
and communicating with an expulsion duct; a second non-return
member arranged between the compression chamber and the expulsion
duct to allow the passage of fluid from compression chamber to the
expulsion duct, and to prohibit the passage of fluid from the
expulsion duct to the compression chamber; and wherein: the hollow
body includes a discharge opening communicating with the expulsion
duct and able to communicate with the intake opening, and a third
non-return member movable between an open position, in which the
expulsion duct communicates with the intake opening, and a closed
position prohibiting the passage of fluid between the expulsion
duct and the intake opening, and the pump includes displacement
elements for moving the third non-return member, and wherein the
controllable element is connected to the expulsion duct of the
pump.
11. The assembly according to claim 10, wherein the controllable
element includes a movable membrane of an expansion vessel
equipping a Rankine system, said Rankine system comprising: an
evaporator, a steam machine arranged downstream from the
evaporator, a condenser arranged downstream from the steam machine,
a pumping device arranged downstream from the condenser, and the
expansion vessel being arranged between the condenser and the
pumping device, the expansion vessel including: an enclosure, said
movable membrane, mounted movably in the enclosure and separating
the enclosure into a first part communicating with the condenser
and the pumping device, and a second part communicating with the
expulsion duct of the pump.
12. The assembly according to claim 10, wherein the controllable
element is a valve actuator, in particular for a motor vehicle
exhaust device.
Description
RELATED APPLICATION
[0001] This application claims priority to FR 15 51595, filed Feb.
25, 2015.
TECHNICAL FIELD
[0002] The present invention relates to a pump, designed to
increase the pressure in an enclosed space, in particular to act on
a pressure-sensitive element, for example a pneumatic actuator.
BACKGROUND
[0003] Already known in the state of the art is a pump including a
hollow body and a piston, housed in the hollow body movably in a
longitudinal direction, the piston defining, with the hollow body,
a compression chamber with a variable volume based on a position of
the piston in the longitudinal direction. The hollow body typically
includes: an intake opening, designed to communicate with a fluid
source and able to communicate with the compression chamber; a
first non-return arranged between the intake opening and the
compression chamber, which allows the passage of fluid from the
intake opening to the compression chamber and prohibits the passage
of fluid from the compression chamber to the intake chamber; an
expulsion opening, which emerges in the compression chamber and
communicates with an expulsion duct; and a second non-return
arranged between the compression chamber and the expulsion duct,
which allows the passage of fluid from compression chamber to the
expulsion duct and prohibits the passage of fluid from the
expulsion duct to the compression chamber.
[0004] When the piston moves in a first direction, the volume of
the compression chamber increases and fluid fills the compression
chamber by passing through the intake opening.
[0005] When the piston moves in a second direction opposite the
first, the volume of the compression chamber decreases and the
fluid is expelled through the expulsion opening. The first and
second non-returns allow the fluid to flow only in one
direction.
[0006] By applying oscillating movements to the piston in the first
direction, then the second direction along the longitudinal
direction, this piston expels a desired quantity of fluid in the
expulsion duct. When this expulsion duct is connected to an
enclosed space, the pressure in the enclosed space then increases.
The invention also aims to improve such a pump, in particular for
applications where a quick return to the initial position may be
desired.
SUMMARY
[0007] To that end, the invention in particular relates to a pump
including a hollow body and a piston, housed in the hollow body
movably in a longitudinal direction, defining, with the hollow
body, a compression chamber with a variable volume depending on the
position of the piston in the longitudinal direction, the hollow
body including: an intake opening designed to communicate with a
fluid source and able to communicate with the compression
chamber,
[0008] a first non-return member arranged between the intake
opening and the compression chamber to allow the passage of fluid
from the intake opening to the compression chamber, and to prohibit
the passage of fluid from the compression chamber to the intake
chamber,
[0009] an expulsion opening emerging in the compression chamber and
communicating with an expulsion duct,
[0010] a second non-return member arranged between the compression
chamber and the expulsion duct to allow the passage of fluid from
compression chamber to the expulsion duct, and to prohibit the
passage of fluid from the expulsion duct to the compression
chamber
[0011] and wherein
[0012] the hollow body includes a discharge opening communicating
with the expulsion duct and able to communicate with the intake
opening, and a third non-return member movable between an open
position, in which the expulsion duct communicates with the intake
opening, and a closed position prohibiting the passage of fluid
between the expulsion duct and the intake opening, and
[0013] the pump includes a movable element or member to move for
the third non-return member.
[0014] By moving the third non-return member into the open
position, the expulsion duct communicates with the intake opening,
such that the high-pressure fluid contained in the expulsion duct
is discharged through the intake opening, until the pressure in the
expulsion duct is reduced to the pressure of the fluid source, for
example the atmospheric pressure.
[0015] It is thus possible to discharge the pump quickly, making
its use possible for applications where such a quick discharge is
desirable.
[0016] A pump according to the invention can further comprise one
or more of the following features, considered alone or in any
technically possible combinations.
[0017] The displacement member includes: a ferromagnetic element
movable between a first position, in which the third non-return
member is in the open position, and a second position, in which the
third non-return means are in the closed position, an elastic
member biasing the ferromagnetic element toward its first position,
and an electric coil surrounding the ferromagnetic element and
electrically connected to a power supply able to apply an
adjustable current. The position of the ferromagnetic element
depends on the voltage of the current.
[0018] The third non-return member includes a non-return gate
biased in the closed position by an elastic member, and the
displacement member includes an actuating element secured to the
piston and designed to cooperate with the non-return gate to move
the non-return gate into the open position by pushing the
non-return gate against the biasing of the elastic member, when the
piston is in a predetermined discharge position, and said
ferromagnetic element is formed by a rod secured to the piston.
[0019] The piston is movable, in the longitudinal direction,
between: a first extreme position, in which the actuating element
cooperates with the non-return gate, and in which the volume of the
compression chamber is maximal, a second extreme position, in which
the volume of the compression chamber is minimal, and at least one
intermediate position, in which the actuating element is kept at a
distance from the non-return gate.
[0020] The third non-return member includes a non-return gate, the
ferromagnetic element being formed by this non-return gate.
[0021] The piston includes a rod made from a ferromagnetic
material, in particular soft iron, extending in the longitudinal
direction, the pump including an electric coil surrounding the rod
and electrically connected to a power supply able to apply a
variable electric current, the position of the piston depending on
the voltage of the electric current.
[0022] The intake opening includes a filter.
[0023] The pump includes a variable volume fluid reservoir forming
the fluid source.
[0024] The fluid is gas, in particular air.
[0025] The invention also relates to an assembly of a pump and a
pressure-sensitive controllable element controlled by the pump,
wherein the pump is as previously defined, the controllable element
being connected to the expulsion duct of the pump.
[0026] For example, the controllable element includes a movable
membrane of an expansion vessel equipping a Rankine system, the
Rankine system comprising:
[0027] an evaporator,
[0028] a steam machine arranged downstream from the evaporator,
[0029] a condenser arranged downstream from the steam machine,
[0030] a pumping device arranged downstream from the condenser,
and
[0031] the expansion vessel arranged between the condenser and the
pumping device, the expansion vessel including:
[0032] an enclosure,
[0033] the movable membrane, mounted movably in the enclosure and
separating the enclosure into a first part communicating with the
condenser and the pumping device, and a second part communicating
with the expulsion duct of the pump.
[0034] According to another example, the controllable element is a
valve actuator, in particular for a motor vehicle exhaust
device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The invention will be better understood using the following
description, provided solely as an example and done in reference to
the appended figures, in which:
[0036] FIG. 1 is a diagrammatic sectional view of an assembly of a
pump according to one example embodiment and a controllable element
controlled by the pump, the pump including a piston shown in an
intermediate position;
[0037] FIG. 2 is a view similar to FIG. 1 of the pump in which the
piston is shown in a first extreme position;
[0038] FIG. 3 is a view similar to FIG. 2 of the pump in which the
piston is shown in a second extreme position;
[0039] FIG. 4 diagrammatically shows an assembly of a pump
according to a second example embodiment and an element controlled
by the pump;
[0040] FIG. 5 is a view similar to FIG. 4 of the pump according to
FIG. 4 in a discharge situation;
[0041] FIG. 6 diagrammatically shows a pump according to a third
example embodiment of the invention; and
[0042] FIG. 7 shows an assembly of a pump according to the
invention and an element controllable by the pump, equipping a
Rankine system.
DETAILED DESCRIPTION
[0043] FIG. 1 shows an assembly 8 including a pump 10 and a
pressure-sensitive controllable element 12 that is controlled by
the pump 10.
[0044] In this example, the controllable element 12 is a pneumatic
actuator designed to control an exhaust valve of an exhaust device
of the motor vehicle. This controllable element 12 traditionally
includes a body 14 defining a chamber 16 in which a tight membrane
18 is housed separating the chamber 16 into first 16A and second
16B compartments. The membrane 18 is movable in the chamber 16,
such that the volume of the compartments 16A and 16B depends on the
position of this membrane 18.
[0045] The membrane 18 is connected to a rod 20, such that the
movement of the membrane 18 causes the movement of the rod 20.
[0046] The actuator 12 lastly includes an elastic member 22, in
particular a spring, applying an elastic biasing force, biasing the
membrane 18 toward a first position, shown in FIG. 1, in which the
volume of the first compartment 16A is minimal or null, and the
volume of the second compartment 16B is maximal. The membrane 18 is
movable to a second position, in which the volume of the first
compartment 16A is maximal and the volume of the second compartment
16B is minimal or null.
[0047] The rod 20 is connected to the exhaust valve. The exhaust
valve is movable between a closed position and an open position.
More particularly, the exhaust valve is in the closed position when
the membrane 18 is in the first position, and in the open position
when the membrane 18 is in the second position.
[0048] It will be noted that the membrane 18 can assume various
intermediate positions between the first and second positions, each
of these intermediate positions corresponding to an intermediate
position of the valve between the closed position and the open
position.
[0049] In order to move the membrane 18, the pressure is varied in
the first compartment 16A. Thus, by increasing this pressure, a
pressure force is opposed against the elastic biasing force of the
elastic member 22, which makes it possible to move the membrane 18
when the pressure force is greater than the elastic force.
[0050] Conversely, when the pressure decreases, the pressure force
becomes lower than the elastic force, such that the membrane 18 is
returned toward its first position by the elastic member 22.
[0051] The pressure in the first compartment 16A is controlled by
the pump 10.
[0052] The pump 10 includes a hollow body 24 and a piston 26 housed
in the hollow body 24 and movably in the longitudinal direction X.
The hollow body 24, for example, has a generally cylindrical shape
extending in the longitudinal direction X.
[0053] The piston 26 defines, with the hollow body 24, a
compression chamber 28 with a variable volume based on a position
of the piston 26 in the longitudinal direction X.
[0054] The piston 26 is movable in the longitudinal direction X
between a first extreme position, shown in FIG. 2, in which the
volume of the compression chamber 28 is maximal, and a second
extreme position, shown in FIG. 3, in which the volume of the
compression chamber 28 is minimal. The piston 26 can assume any
intermediate position between the first and second extreme
positions, and in particular a so-called idle position, shown in
FIG. 1, which will be described later in more detail.
[0055] The hollow body 24 includes an intake opening 30, designed
to communicate with a fluid source, and able to communicate with
the compression chamber 28.
[0056] The fluid source is, for example, the atmosphere surrounding
the pump 10, in which case the fluid is air. In this case, the
intake opening 30 is advantageously equipped with an air filter in
order to avoid any contamination of the hollow body 24 by unwanted
particles and/or liquids.
[0057] Alternatively, the fluid source is formed by a reservoir
connected to the intake opening 30. Such a reservoir has a variable
volume, such that the pressure remains constant in this reservoir
when fluid is suctioned by the pump 10. In this case, the fluid can
also be air, or alternatively oil or any other possible fluid.
[0058] In the described example, the intake opening 30 communicates
with the compression chamber 28 through orifices 32 arranged in the
piston 26. A first non-return member 34, arranged between the
intake opening 30 and the compression chamber 28, allows the
passage of fluid from the intake opening 30 toward the compression
chamber 28, and prohibits the passage of fluid from the compression
chamber 28 toward the intake opening 30. In the described example,
the first non-return member 34 is formed by a non-return membrane
able to unstick from the piston 26 when fluid passes through from
the intake opening 30 toward the compression chamber 28, and to
press against the piston 26 so as to close off the orifices 32 to
prohibit the passage of fluid from the compression chamber 28
toward the intake opening 30.
[0059] The hollow body 24 further includes an expulsion opening 36,
emerging in the compression chamber 28, and communicating with the
expulsion duct 38. A second non-return member 40, in particular a
non-return gate of the traditional type, is arranged between the
expulsion opening 36 and the expulsion duct 38 to allow the passage
of fluid from the compression chamber 28 toward the expulsion duct
38, and to prohibit the passage of fluid from the expulsion duct 38
toward the compression chamber 28.
[0060] When the piston 26 moves from its idle position, shown in
FIG. 1, toward its second extreme position, shown in FIG. 3, the
fluid contained in the compression chamber 28 is expelled through
the expulsion opening 36, this expulsion being authorized by the
second non-return member 40. During this movement, the non-return
membrane of the first non-return member 34 is pressed against the
passage orifices 32 of the piston 26, such that the fluid does not
escape through these passage orifices 32.
[0061] When the piston 26 moves from its second extreme position
shown in FIG. 3 toward its idle position shown in FIG. 1, the
volume of the compression chamber 28 increases, and its pressure
decreases such that fluid is suctioned in this compression chamber
28. Due to the second non-return member 40, the fluid is not
suctioned from the expulsion duct 38. However, the first non-return
member 34 allows the passage of fluid through the passage orifices
32, such that the fluid is suctioned from the fluid source through
the intake opening 30 and the passage orifices 32.
[0062] By reiterating the movements of the piston 26 described
above, fluid is gradually introduced into the expulsion duct
38.
[0063] As shown in FIG. 1, the expulsion duct 38 communicates with
the first compartment 16A of the actuator 12, which is an enclosed
space, such that the gradual introduction of fluid in the expulsion
duct 38 increases the pressure in this expulsion duct 38 and in the
first compartment 16A up to a desired pressure. This pressure
increase causes the movement of the membrane 18, as previously
indicated.
[0064] The piston 26 includes a rod 42 made from a ferromagnetic
material, in particular soft iron, extending in the longitudinal
direction X in the hollow body 24.
[0065] The pump 10 then includes an electric coil 44, surrounding
the rod 42, and electrically connected to a power supply able to
apply a variable current to the electric coil 44. Thus, the
position of the piston 26 depends on the voltage of this electric
current. More particularly, an increase in the electric current
tends to drive the piston 26 toward its second extreme
position.
[0066] The pump 10 further includes an elastic member 46, applying
an elastic force biasing the piston 26 toward its first extreme
position. Thus, the magnetic force induced by the electric current
flowing in the coil 44 opposes the elastic force applied by the
elastic member 46 on the piston 26. The stronger the electric
current is, the greater the magnetic force is, the piston 26 moving
toward its second extreme position when the magnetic force is
greater than the elastic force of the elastic member. Conversely,
by decreasing the electric current, the magnetic force decreases,
and the piston 26 moves toward its first extreme position when this
magnetic force is below the elastic force applied by the elastic
member 46.
[0067] The piston 26 stays in its idle position, shown in FIG. 1,
when a relatively low holding current, for example 5 volts, is
applied to the coil 44, in order to generate an opposite magnetic
force with a value equal to the elastic force.
[0068] The hollow body 24 of the pump 10 according to the invention
includes a discharge opening 48, communicating with the expulsion
duct 38 and able to communicate with the intake opening 30. For
example, this discharge opening 48 communicates with the expulsion
duct 38 via a bypass duct 50.
[0069] A third non-return member 52 is arranged between this
discharge opening 48 and this bypass duct 50. This third non-return
member 52 is movable between an open position, shown in FIG. 2, in
which the expulsion duct 38 communicates with the intake opening
30, and a closed position prohibiting the passage of fluid between
the expulsion duct 38 and the intake opening 30.
[0070] The pump 10 includes a movable element or member 54 to move
the third non-return member 52.
[0071] In the first described example, the third non-return member
52 includes a non-return gate 52A biased in the closed position by
an elastic member 52B. The movable member 54 includes an actuating
element 56, in particular formed by a striker, secured to the
piston 26, and for example, supported by the rod 42. This actuating
element 56 is designed to cooperate with the non-return gate 52A to
move it into the open position, by pushing it against the biasing
of the elastic member 52B, when the piston 26 is in the first
extreme position. This first extreme position therefore forms a
discharge position.
[0072] It will be noted that the piston 26 enters its first extreme
position when the electric current flowing in the coil 44 is null,
in which case no magnetic force opposes the elastic force applied
by the elastic member 46 on the piston 26. The discharge can
therefore be done simply and quickly, by interrupting the electric
current flowing in the coil 44.
[0073] FIG. 4 shows a pump 10 according to a second example
embodiment of the invention. In this FIG. 4, the elements similar
to those of the preceding figures are designated by identical
references.
[0074] In this example, the pump 10 is an oil pump. In this case,
the actuator 12 is a jack, including a piston 58 movable in a body
60, and separating this body 60 into a first compartment 62
communicating with the evacuation duct 38 of the pump 10, and a
second compartment 64.
[0075] The jack 12 also includes an elastic member 66 biasing the
piston 58 toward a first position in which the first compartment 62
has a minimal or null volume. The rod 20 is secured to the piston
58 on the one hand, and to a valve element 68 on the other hand,
such that this valve element 68 is movable based on the position of
the piston 58 via the rod 20.
[0076] According to this second embodiment, the intake opening 30
is connected to a reservoir 70 filled with oil, and including a
flexible pouch 72 with a variable volume based on the quantity of
oil in that pouch 72. The pump 10 includes an intake duct 74 that
extends between the intake opening 30 and the compression chamber
28.
[0077] The first non-return member 34 then includes a non-return
gate authorizing the passage of fluid from the intake duct 74
toward the compression chamber 28 and prohibiting the passage of
fluid from the compression chamber 28 toward the intake duct
74.
[0078] In this embodiment, the piston 26 does not include a passage
opening. However, as before, the volume of the compression chamber
28 depends on the position of the piston 26.
[0079] As before, the compression chamber 28 includes an expulsion
opening 36, emerging in the compression chamber 28, and
communicating with the expulsion duct 38. The second non-return
member 40 is arranged at this expulsion opening 36, between the
compression chamber 28 and the expulsion duct 38, in order to allow
the passage of oil from the compression chamber 28 toward the
expulsion duct 38, and to prohibit the passage of fluid from the
expulsion duct 38 toward the compression chamber 28.
[0080] The operation of this pump is identical to that of the pump
according to the first embodiment.
[0081] According to this second embodiment, the discharge opening
48 is arranged in a discharge duct 76 extending between the
expulsion duct 38 and the intake duct 74. The third non-return
member 52 is housed in this discharge duct 76.
[0082] The movable member 54 then includes a ferromagnetic element
78 movable between a first position, in which the third non-return
member 52 is in the open position, and a second position, in which
the third non-return member 52 is in a closed position. The movable
member 54 also includes an elastic member 80 biasing the
ferromagnetic element 78 toward its first position, as well as a
coil 82 surrounding the ferromagnetic element 78, and electrically
connected to a power supply able to apply an adjustable current,
the position of the ferromagnetic element depending on the voltage
of the current. More particularly, the third non-return member 52
includes a non-return gate, with the ferromagnetic element 78 being
formed by this non-return gate.
[0083] As shown in FIG. 5, when the current is interrupted in the
coil 82, no magnetic force is applied on the non-return gate 78,
such that it is only subject to the elastic force of the elastic
member 80, which drives it toward its first position. In this
position, the expulsion duct 38 communicates with the intake duct
74, such that the high-pressure oil contained in the expulsion duct
38 is evacuated toward the reservoir 70. Thus, the pump can be
discharged very simply by interrupting the current flowing in the
electric coil 82.
[0084] However, during normal operation of the pump, a holding
current flows continuously in the coil 82 to keep the gate 78 in
its closed position. The magnetic force thus applied to the gate
78, added to the pressure force from the oil contained in the
expulsion duct 38, keeps the gate in the closed position against
the elastic force applied by the elastic member 80.
[0085] FIG. 6 shows a pump 10 according to a third example
embodiment of the invention. In this FIG. 6, the elements similar
to those of the preceding figures are designated by identical
references.
[0086] According to this third embodiment, the pump 10 is an air
pump.
[0087] For example, the intake opening 30 is connected to a
reservoir 70, including a pouch 72 with a variable volume, forming
an air source. The air flows from the intake opening 30 to the
compression chamber 28 via at least one intake duct 74 and by
passing through the first non-return member 34. When the volume of
the compression chamber 28 decreases, the air is expelled up to an
expulsion duct 38, through an expulsion opening 36 including the
second non-return member 40.
[0088] As in the second embodiment, the discharge opening 48 is
arranged between the expulsion duct 38 and the intake duct 74, and
includes a gate 78 made from a ferromagnetic material that is
surrounded by an electric coil 82.
[0089] The operation of this pump 10 according to the third
embodiment is similar to the operation of the pump 10 according to
the second embodiment previously described.
[0090] FIG. 7 shows a Rankine system 100 using a pump 10 according
to the invention, for example according to any one of the
embodiments previously described. More particularly, the pump 10 is
advantageously an air pump.
[0091] The Rankine system 100 traditionally includes an evaporator
102, a steam machine 104 arranged downstream from the evaporator
102, a condenser 106 arranged downstream from the steam machine
104, and a pumping device 108 arranged downstream from the
condenser 106, as well as an expansion vessel 110 arranged between
the condenser and the pumping device 108.
[0092] The Rankine system 100 is designed to recover the exhaust
gas heat emitted by a gasoline or diesel internal combustion
engine, by evaporating the working fluid, for example ethanol
water, R134, R245 or any other fluid having the requisite
characteristics, in the evaporator 102 generally arranged
downstream from a pollution control system.
[0093] The working fluid is next expanded in the steam machine 104,
of the piston engine type, the turbine type, or any other type
making it possible to convert a pressurized gas at a certain
temperature into mechanical work. The steam machine 104 therefore
provides mechanical work, which can, for example, next be converted
into electricity.
[0094] Once expanded, the fluid is condensed in the condenser 106,
which is formed by a heat exchanger with a cold source, for example
the cooling water of the motor vehicle or the ambient air.
[0095] Once the fluid has returned to liquid state, it is pumped by
the pumping device 108 to be reintroduced into the evaporator 102.
The pressure obtained in this evaporator 102 is imposed by the
steam machine 104.
[0096] Such a Rankine system operates in a closed loop, without
loss of working fluid.
[0097] For the proper operation of the Rankine system, it is
necessary to minimize the external leaks and prohibit air from
entering. Certain fluids, such as ethanol water, are completely
liquid at the pressures and temperatures encountered when the
vehicle is stopped (atmospheric pressures and temperatures). Air
must absolutely be banished in an enclosed system, since it is
compressible. Thus, if an air bubble was suctioned by the pumping
device 108, the flow rate would be unpredictable. Consequently,
when the vehicle is stopped and cooled, all of the fluid is in
liquid form if the internal pressure of the system is at the
atmospheric pressure.
[0098] Conversely, if the volume dedicated to the working fluid is
constant, the internal cold pressure would decrease until reaching
a pressure of approximately 0.1 bars, corresponding to the
saturating steam pressure around 20 to 40.degree. C. In other
words, part of the working fluid would remain in steam form at a
very low pressure and ambient temperature.
[0099] A vehicle such as a car is stopped for the majority of its
lifetime. Yet under these conditions, the pressure prevailing
inside is so low relative to the atmospheric pressure that the risk
of introducing a little bit of air during these long exposures is
high. To eliminate any leakage risk, it is necessary for the system
to be at atmospheric pressure during stops of the vehicle. If the
system is at atmospheric pressure when stopped without air inside,
then the entire fluid circuit is in liquid form.
[0100] When the engine is turned on, the exhaust gases heat the
working fluid to convert it into steam. This steam has a lower
density than the corresponding liquid. The additional volume
necessary for steam formation can be procured by an additional
element, which is the expansion vessel 110.
[0101] The expansion vessel 110 includes an enclosure 112 and a
membrane 114, mounted movably in the enclosure 112, separating the
enclosure 112 into a first part 116 communicating with the
condenser 106 and the pumping device 108, and a second part 118
communicating with the expulsion duct 38 of the pump 10. Thus, the
pump 10 can manage the pressure in this second part 118 of the
enclosure 112. This second part 118 is, for example, equipped with
a pressure sensor, making it possible to determine the pressure in
this second part 118.
[0102] Advantageously, the membrane 114 is made from metal to have
satisfactory sealing and to prevent the migration of gas particles
through this membrane during the lifetime of the vehicle.
[0103] It should be noted that the system is generally not
completely tight. It is therefore preferable to store, in the
expansion vessel 110, a buffer volume of working fluid that will
decrease as part of the fluid from the system is lost. Such a
buffer volume is sufficient to cover the leakage of the system,
which is approximately 200 cm.sup.3 for the lifetime of the
vehicle, which is generally 15 years and 5000 hours of use.
[0104] In such a Rankine system, once the working fluid is expanded
(at the outlet of the steam machine 104), it is condensed in the
condenser 106. The condenser is supplied with a low-temperature
fluid (for example, engine cooling water, or ambient air). The
condensation pressure depends on the temperature of this
low-temperature fluid.
[0105] For certain working fluids (water, water ethanol mixture,
acetone, toluene, etc., for example), the expansion vessel 110
makes it possible to account for the increased volume of the
working fluid due to its passage from the liquid state to the steam
state in part of the evaporator 102, in the steam machine 104 and
in part of the condenser 106.
[0106] The aim of the association of the expansion vessel 110 with
the condenser 106 is to ensure the lowest possible pressure at the
outlet of the steam machine 104 while ensuring that the working
fluid is completely liquid at the outlet of the condenser 106, and
above all at the inlet of the high-pressure pump 108, in order to
ensure that the latter is always pumping liquid.
[0107] It is therefore necessary to manage the pressure of the
working liquid between the condenser 106 and the pump 108. To that
end, the temperature of the cold source (engine water generally
known in the injection computer, or ambient air, which is also
measured at the engine intake) is known, as well as the flow rate
of this cold source (water flow rate depends on the engine rating,
and the air flow rate depends on the speed of the vehicle and/or
the speed of the fan). This temperature and this flow rate make it
possible to calculate the thermal flow.
[0108] It is therefore possible to know the temperature of the
working fluid either by calculation or by measuring it directly.
The geometric definition of the expansion vessel 110 makes it
possible to know, at any point in the operation of the cycle, the
resultant pressure of the working fluid. Yet in some cases, this
pressure must be corrected to be sure of the working fluid
state.
[0109] To adapt the pressure to the temperature of the cold source,
a pressure is applied in the part 116 that is managed using the
pump 10.
[0110] Advantageously, the pressure in the first part 116 is
measured by the pressure sensor, which makes it possible to apply
the necessary pressure to ensure that the fluid is liquid at the
outlet of the condenser 106, irrespective of the temperature of the
cold source.
[0111] It will be noted that the invention is not limited to the
described embodiment, but could assume various alternatives.
[0112] Although an embodiment of this invention has been disclosed,
a worker of ordinary skill in this art would recognize that certain
modifications would come within the scope of this disclosure. For
that reason, the following claims should be studied to determine
the true scope and content of this disclosure.
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