U.S. patent application number 13/316339 was filed with the patent office on 2013-03-21 for pump structure for urea scr system.
This patent application is currently assigned to Kia Motors Corporation. The applicant listed for this patent is Pil Seon Choi, Chang Ho Ham, Bo sung Lee, Dong Myoung RYOO, Buyeol Ryu. Invention is credited to Pil Seon Choi, Chang Ho Ham, Bo sung Lee, Dong Myoung RYOO, Buyeol Ryu.
Application Number | 20130071268 13/316339 |
Document ID | / |
Family ID | 47750994 |
Filed Date | 2013-03-21 |
United States Patent
Application |
20130071268 |
Kind Code |
A1 |
RYOO; Dong Myoung ; et
al. |
March 21, 2013 |
PUMP STRUCTURE FOR UREA SCR SYSTEM
Abstract
A pump unit for a urea-SCR system may use a fuel pump of a
vehicle engine and may have a case portion surrounding a motor
portion and a pump portion. The motor portion may include a barrier
wall surrounding a rotator so as to separate the rotator from a
stator of the motor portion, and the pump portion includes a shield
in which a suction hole and a supply hole for fluid are formed and
that is disposed between the pump portion and the motor portion so
as to prevent fluid from leaking into the motor portion, so the
motor is protected from the urea solution to prevent corrosion
thereof, manufacturing cost is reduced, and noise caused by the
vibration is reduced.
Inventors: |
RYOO; Dong Myoung;
(Yongin-city, KR) ; Ryu; Buyeol; (Hwaseong-si,
KR) ; Ham; Chang Ho; (Ansan-city, KR) ; Lee;
Bo sung; (Daejeon, KR) ; Choi; Pil Seon;
(Anyang-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RYOO; Dong Myoung
Ryu; Buyeol
Ham; Chang Ho
Lee; Bo sung
Choi; Pil Seon |
Yongin-city
Hwaseong-si
Ansan-city
Daejeon
Anyang-si |
|
KR
KR
KR
KR
KR |
|
|
Assignee: |
Kia Motors Corporation
Seoul
KR
Hyundai Motor Company
Seoul
KR
|
Family ID: |
47750994 |
Appl. No.: |
13/316339 |
Filed: |
December 9, 2011 |
Current U.S.
Class: |
417/410.4 |
Current CPC
Class: |
F04C 15/0034 20130101;
F04C 2210/1083 20130101; F04C 2/18 20130101; F04B 17/03 20130101;
F04C 2/10 20130101 |
Class at
Publication: |
417/410.4 |
International
Class: |
F04B 17/03 20060101
F04B017/03 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2011 |
KR |
10-2011-0094788 |
Claims
1. A pump unit for a urea-SCR system that uses a fuel pump of a
vehicle engine, the pump unit comprising: a case portion
surrounding a motor portion and a pump portion; wherein the motor
portion includes a barrier wall surrounding a rotator so as to
separate the rotator from a stator of the motor portion; and the
pump portion includes a shield in which a suction hole and a supply
hole for fluid are formed and that is disposed between the pump
portion and the motor portion so as to prevent fluid from leaking
into the motor portion.
2. The pump unit for a urea-SCR system of claim 1, wherein the
barrier wall is made of a corrosion prevention material.
3. The pump unit for a urea-SCR system of claim 1, wherein the pump
portion is made up of one of an inscribed gear pump, a
circumscribed gear pump, and a gerotor pump.
4. The pump unit for a urea-SCR system of claim 1, wherein a center
hole is formed in the shield, and a shaft of the fuel pump
penetrates the center hole to connect to the motor portion.
5. The pump unit for a urea-SCR system of claim 4, wherein a
bearing is disposed between the shaft and the center hole and
between the shaft and the barrier wall.
6. The pump unit for a urea-SCR system of claim 5, wherein an
O-ring is disposed between the bearing and the shield to prevent
leakage of the fluid.
7. The pump unit for a urea-SCR system of claim 1, wherein the case
portion includes a main case surrounding a side surface of the
motor portion and the pump portion and an upper case covering an
upper portion of the motor portion.
8. The pump unit for a urea-SCR system of claim 7, wherein the
barrier wall is integrally formed with the main case.
9. The pump unit for a urea-SCR system of claim 7, wherein the
barrier wall has a cylindrical shape of which the upper portion
thereof is closed, and a flange is formed at a lower portion of the
barrier wall, wherein the barrier wall is engaged with a circular
end portion that is formed along an interior circumference of the
main case through the flange.
10. The pump unit for a urea-SCR system of claim 9, wherein a
groove is formed at an upper surface of the end portion so as to
prevent the fluid from leaking between the end portion and the
flange, and an O-ring is inserted into the groove.
11. The pump unit for a urea-SCR system of claim 1, wherein the
motor portion is a brushless direct current (BLDC) motor.
12. The pump unit for a urea-SCR system of claim 1, further
comprising a cover surrounding an exterior circumference of the
rotator so as to prevent corrosion of the rotator.
13. The pump unit for a urea-SCR system of claim 12, wherein the
cover is formed by over-molding a plastic material.
14. The pump unit for a urea-SCR system of claim 2, wherein the
corrosion prevention material is an SUS material.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of
Korean Patent Application No. 10-2011-0094788 filed Sep. 20, 2011,
the entire contents of which application is incorporated herein for
all purposes by this reference.
BACKGROUND OF INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to a pump structure for a UREA
SCR system, and more particularly to a pump structure for a UREA
SCR system that effectively prevents a leak of the urea solution to
protect the motor portion thereof.
[0004] 2. Description of Related Art
[0005] Vehicles are divided into passenger vehicles, buses, and
trucks according to a type thereof, and they can be further divided
into gasoline vehicles that use gasoline, diesel vehicles that use
diesel, and LPG vehicles that use liquefied petroleum gas according
to the type fuel used.
[0006] A diesel engine combusts fuel in an oxygen surplus condition
to generate a large amount of NOx as a harmful material compared to
a gasoline engine, and it is difficult to reduce the NOx in the
lean condition of the diesel engine. Accordingly, a urea selective
catalytic reduction (urea-SCR) system is an art that has been most
actively developed as a NOx elimination method.
[0007] The urea-SCR system supplies a urea (NH.sub.2-CO-NH.sub.2)
solution to an exhaust gas line, the urea solution is resolved by
high temperature exhaust gas to be transformed to NH.sub.3 and
HNCO, and the HNCO is discomposed by water of the exhaust gas to be
transformed into ammonia and CO2. The ammonia that is generated as
stated above is used to transform NOx into N.sub.2+O.sub.2 through
a catalytic reaction.
[0008] The urea-SCR system includes an injector that injects the
urea solution, a pump that supplies the urea solution from a urea
tank to the injector, and a CPU that controls injection pressure
and injection time.
[0009] It is difficult to use a pump such as a gasoline fuel pump
and a diesel fuel pump that is used in a general vehicle engine so
as to supply the urea solution. Because the urea solution is
strongly alkaline at pH 9-11 to have strong corrosion ability, the
urea solution corrodes most metals except for an SUS material. When
a general fuel pump is used to pump the urea solution, the pump
corrodes and consequently malfunctions after four to six hours.
[0010] Accordingly, as shown in FIG. 1, a special urea supply pump
is used to eliminate the corrosion problem in a conventional art.
That is, a pump portion 2 of a urea supply pump is disposed in a
tank 4, a motor portion 1 is disposed outside the tank and
separated from the outside wall of the tank, and the pump is
rotated by a magnetic coupling 3 having plurality of magnets in the
upper/lower portion thereof to prevent corrosion of the pump.
[0011] However, as a general fuel pump cannot be used as described
above, a separate urea pump is needed so the cost is increased, and
particularly the expensive magnetic coupling as shown in FIG. 1
needs to be used so as to prevent the corrosion of the urea supply
pump which further increases the cost, and there is an additional
problem that operating noise is generated by the complicated
structure having the magnetic coupling.
[0012] The information disclosed in this Background section is only
for enhancement of understanding of the general background of the
invention and should not be taken as an acknowledgement or any form
of suggestion that this information forms the prior art already
known to a person skilled in the art.
SUMMARY OF INVENTION
[0013] Various aspects of the present invention provide for a pump
structure for a urea-SCR system having advantages of using a fuel
pump that is used in a vehicle engine to save production cost,
reduce noise, and simultaneously prevent corrosion caused by a urea
solution.
[0014] A pump structure for a urea-SCR system as a means for
resolving the above problem is provided in various aspects of the
present invention. A pump unit for a urea-SCR system that uses a
fuel pump for a vehicle engine having a case portion surrounding a
motor portion and a pump portion according to various aspects of
the present invention, wherein the motor portion includes a barrier
wall surrounding a rotator so as to separate the rotator from a
stator of the motor portion, and the pump portion includes a shield
in which a suction hole and a supply hole for fluid are formed and
that is disposed between the pump portion and the motor portion so
as to prevent fluid from leaking into the motor portion.
[0015] The barrier wall may be made of corrosion prevention
material including an SUS material.
[0016] The pump portion may be made up of one of an inscribed gear
pump, a circumscribed gear pump, and a gerotor pump.
[0017] A center hole may be formed in the shield, and a shaft of
the fuel pump penetrates the center hole to connect to the motor
portion.
[0018] A bearing may be disposed between the shaft and the center
hole and between the shaft and the barrier wall.
[0019] An O-ring may be disposed between the bearing and the shield
so as to prevent leakage of the fluid.
[0020] The case portion may include a main case surrounding a side
surface of the motor portion and the pump portion and an upper case
covering an upper portion of the motor portion.
[0021] The barrier wall may be integrally formed with the main
case.
[0022] The barrier wall may have a cylindrical shape of which the
upper portion thereof is closed, and a flange is formed at a lower
portion of the barrier wall, wherein the barrier wall is engaged
with a circular end portion that is formed along an interior
circumference of the main case through the flange.
[0023] A groove may be formed at an upper surface of the end
portion so as to prevent the fluid from leaking between the end
portion and the flange, and an O-ring is inserted into the
groove.
[0024] The motor portion may be a brushless direct current (BLDC)
motor.
[0025] The pump unit for a urea-SCR system may further include a
cover surrounding an exterior circumference of the rotator so as to
prevent corrosion of the rotator.
[0026] The cover may be formed by over-molding a plastic
material.
[0027] In accordance with the pump structure for the UREA-SCR
system of the present invention, most parts of a pump for vehicle
engine can be used to reduce production cost, a separate
complicated structure such as a conventional art is not necessary,
and there is an effect for reducing noise by pulsation and
vibration of fluid.
[0028] Also, the shield divides the pump portion and the motor
portion, the suction hole and the supply hole are both formed in
the pump portion, and therefore there is an effect that the urea
solution of the urea-SCR system does not flow into the motor
portion to prevent corrosion of the motor portion.
[0029] Also, if the urea solution leaks through the shield, the
stator is protected from the corrosion by the barrier wall that
separates the stator from the rotator of the motor portion, and the
cover surrounding the exterior circumference, which is formed by
the plastic over-molding, protects the rotator from the urea
solution.
[0030] The methods and apparatuses of the present invention have
other features and advantages which will be apparent from or are
set forth in more detail in the accompanying drawings, which are
incorporated herein, and the following Detailed Description, which
together serve to explain certain principles of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a drawing showing a urea supply pump structure
according to a conventional art.
[0032] FIG. 2 is an exploded perspective view of a pump structure
for an exemplary urea-SCR system according to the present
invention.
[0033] FIG. 3 is a cross-sectional view of a pump structure for an
exemplary urea-SCR system according to the present invention.
[0034] FIG. 4 is a drawing showing an exemplary procedure for
covering a rotator exterior circumference according to the present
invention.
[0035] FIG. 5 is a cross-sectional view of an exemplary pump
structure in which a barrier wall is integrally formed with a main
case according to the present invention.
[0036] FIG. 6 is an exploded perspective view of a pump structure
for an exemplary urea-SCR system to which a gerotor pump is applied
according to the present invention.
DETAILED DESCRIPTION
[0037] Reference will now be made in detail to various embodiments
of the present invention(s), examples of which are illustrated in
the accompanying drawings and described below. While the
invention(s) will be described in conjunction with exemplary
embodiments, it will be understood that present description is not
intended to limit the invention(s) to those exemplary embodiments.
On the contrary, the invention(s) is/are intended to cover not only
the exemplary embodiments, but also various alternatives,
modifications, equivalents and other embodiments, which may be
included within the spirit and scope of the invention as defined by
the appended claims.
[0038] As shown in FIG. 2, a pump structure of a urea-SCR system
according to various embodiments of the present invention uses a
fuel pump for a vehicle engine including a motor portion 100, a
pump portion 200, and a case portion 300. In the illustrated
exemplary embodiment, the motor portion 100 includes a shaft 110, a
rotator 120, a stator 130, and a barrier wall 140, the pump portion
200 includes a suction hole 210, a supply hole 220, and a shield
230, and the case portion 300 includes a main case 310 and an upper
case 320.
[0039] As shown in FIG. 2, the structure of the motor portion 100
can use a brushless direct current electric (BLDC) motor that is
used in a general vehicle engine in accordance with various
embodiments of the present invention.
[0040] Generally, the BLDC motor includes the shaft 110, the
rotator 120 that is engaged with an exterior circumference of the
shaft 110, and the stator 130 that generates an induced
electromotive force for rotating the rotator 120. The rotator 120
is rotatably disposed on the stator 130 to be separate from the
stator 130.
[0041] As shown in FIG. 2, the rotator 120 includes a rotor (e.g.,
iron coil) 121 that is fixed on an exterior circumference of the
shaft 110 and a permanent magnet 122 that is disposed at the
outside or the inside of the rotor 121, and the stator 130 includes
a coil 131 that generates an induced electromotive force and a
stator core 132 that is inserted into the coil 131. Also,
insulators 133A and 133B are respectively disposed at a lower
portion and an upper portion of the stator 130 to insulate
electricity or heat.
[0042] In the motor portion 100 according to various embodiments of
the present invention, the rotator 120 is spatially separated from
the stator 130 by the barrier wall 140.
[0043] As shown in FIG. 2, the barrier wall 140 surrounds the
rotator 120 so as to separate the rotator 120 of the motor portion
100 from the stator 130 of the motor portion 100.
[0044] Although some of the urea solution flows into the motor
while the urea solution is pumped in the urea-SCR system, the
rotator 120 is affected by the urea solution but the stator 130 is
not affected thereby because of the barrier wall 140. The coil 131
that is an essential component of the motor, the stator 130
including the stator core 132, electric wires, and the electrode
are protected from the urea solution by the barrier wall 140.
[0045] Accordingly, the barrier wall 140 is to be made of a
corrosion prevention material, and in various embodiments, the
material can be made of an SUS material.
[0046] The shape of the barrier wall 140 can be variously formed,
but as shown in FIG. 2 and FIG. 3, the barrier wall in accordance
with various embodiments has a cylindrical shape of which the upper
portion thereof is closed, a flange 141 is formed at a lower
portion thereof, and the flange 141 is engaged with an end portion
311 that is formed along an interior circumference of the main case
310 through a bolt 142.
[0047] Also, as shown in FIG. 2, a groove 311a is formed on an
upper surface of the end portion 311 and an O-ring 20a is inserted
therein such that the fluid cannot leak between the end portion 311
and the flange 141 so as to protect the stator 130 from the urea
solution.
[0048] In this formation, when the urea solution leaks from the
pump portion 200 to flow into the motor portion 100, the stator 130
is protected and only the rotator 120 is affected.
[0049] A cover 123 that is made of the SUS material can be prepared
to prevent the corrosion of the rotator 120 caused by the urea
solution.
[0050] The cover 123 has a cylindrical shape on which the upper
portion and the lower portion are closed to surround an exterior
circumference of the rotator 120, wherein the cover 123 is made by
an over-molding plastic material to prevent the corrosion of the
rotator 120.
[0051] FIG. 4 shows a formation process of the cover 123 of the
rotator 120, wherein the shaft 110 is engaged with the rotor 121 of
the rotator 120, the permanent magnet 122 is inserted into the
cover 123, and the upper surface is covered by the cover 123 to
wrap the exterior circumference of the rotator 120. In various
embodiments, as shown in FIG. 4, the magnet 122 may be an SPM type
that is attached to the outside of the rotor 121, and if the magnet
122 is an IPM type that is inserted into the rotor 121, the cover
123 is formed on the exterior circumference of the rotator 120.
[0052] Meanwhile, in accorance with various embodiments, as shown
in FIG. 5, the barrier wall 140 can be integrally formed with the
main case 310. One will appreciate that the barrier wall may be
monolithically formed with the main case. When the barrier wall is
integrally formed, the flange 141 of the barrier wall 140 is not
engaged with the end portion 311 of the main case 310 through the
bolt 142, but rather is integrally formed with the end portion 311.
Accordingly, there is an effect of preventing leakage of the urea
solution compared to the case of FIG. 2 in which the barrier wall
140 is engaged with the main case 310 through the bolt 142.
[0053] Meanwhile, as shown in FIG. 3, it is desirable for a bearing
10a to be disposed between the rotator 120 and the barrier wall 140
such that the rotator 120 rotates effectively.
[0054] As the pump portion 200, a pump for a general vehicle engine
can be used. However, an impeller type of pump for a gasoline
engine is inappropriate for the high viscosity urea solution, and
therefore it is desirable that a rotary pump is used. As a rotary
type of pump, an inscribed gear pump, a circumscribed gear pump, or
a gerotor pump can be used.
[0055] FIG. 2 shows a case that a gear pump 240 is used in
accordance with various embodiments, and FIG. 6 shows a case that a
gerotor pump 240 is used instead of the gear pump, wherein the
other configurations are similar to those of FIG. 2.
[0056] The pump portion 200 includes the suction hole 210 and the
supply hole 220 for fluid according to various embodiments of the
present invention. This is different from a structure of a fuel
pump for a vehicle engine, but because the suctioned fuel that is
sucked by a fuel suction portion of a lower portion thereof is
pumped by pump rotation and is supplied to a motor portion thereof
to be discharged through a fuel discharge portion in case of a fuel
pump for a vehicle engine like a general BLDC pump, if this pump
structure is used for the urea-SCR system as it is, there is a
problem that the motor that is made of copper or steel corrodes
during pumping of the urea solution. Accordingly, the fluid suction
hole 210 and the supply hole 220 are formed in the pump portion 200
that is disposed in the motor portion 100 so as to resolve this
problem in the present invention. In accorance with various
embodiments, as shown in FIG. 2, the urea solution that is sucked
through the suction hole 210 does not pass the motor portion 100 to
be discharged through the supply hole 220 such that the motor
portion 100 is protected from the urea solution.
[0057] FIG. 2 shows that the fluid suction hole 210 and the supply
hole 220 are formed together in a case that the pump 240 according
to various embodiments of the present invention is a gear pump
type, and FIG. 6 shows that the fluid suction hole 210 and the
supply hole 220 are formed together in a case that the pump 240
according to various embodiments of the present invention is a
gerotor pump.
[0058] Also, as shown in FIG. 2, in the pump portion 200 according
to various embodiments of the present invention, the shield 230 is
disposed between the pump portion 200 and the motor portion 100 so
as to prevent the fluid from leaking into the motor portion
100.
[0059] The shaft 110 that connects the pump portion 200 with the
motor portion 100 penetrates a center hole that is formed in the
shield 230, and therefore the fluid can leak between the center
hole and the shaft 110. Accordingly, as shown in FIG. 2, a bearing
10b is disposed between the shaft 110 and the center hole of the
shield 230 such that the fluid (e.g., urea solution) cannot leak
into the motor portion 100 disposed in an upper side according to
various embodiments of the present invention. It is desirable that
the shield 230 is made of the SUS material that does not corrode by
the urea solution.
[0060] Also, as shown in FIG. 2 or FIG. 3, an O-ring 20b is
disposed between the bearing 10b and the shield 230 to improve the
leak prevention effect of the urea solution, and O-ring 20c is
disposed at a lower portion of the shield 230 to prevent the
leakage of the fluid of the pump portion 200.
[0061] As shown in FIG. 2, the case portion 300 includes the main
case 310 that surrounds the side surface of the motor portion 100
and the pump portion 200 and the upper case 320 that covers the
upper portion of the motor portion 100, and as shown in FIG. 3, the
main case 310 and the upper case 320 or the main case 310 and the
pump portion 200 are engaged by caulking or another assembly
means.
[0062] Since the pump structure for the urea-SCR system of the
present invention as described above can use most parts of the pump
for a vehicle engine, the production cost is reduced, complicated
structures are not necessary, and noise caused by pulsation and
vibration of the fluid is reduced.
[0063] Further, the pump portion 200 is divided from the motor
portion 100 through the shield 230, and the fluid suction hole 210
and the supply hole 220 are both formed in the pump portion 200
such that the urea solution of the urea-SCR system cannot flow into
the motor portion 100 such that the corrosion of the motor portion
100 is prevented.
[0064] Also, even if the urea solution leaks through the shield
230, the stator 130 is protected from the corrosion by the barrier
wall 140 that separates the rotator 120 from the stator 130 of the
motor portion 100, and the rotator 120 has the cover 123 that is
over-molded by the plastic material to surround the exterior
circumference thereof to be protected from the leaked urea
solution.
[0065] For convenience in explanation and accurate definition in
the appended claims, the terms upper or lower, inside or outside,
and etc. are used to describe features of the exemplary embodiments
with reference to the positions of such features as displayed in
the figures.
[0066] The foregoing descriptions of specific exemplary embodiments
of the present invention have been presented for purposes of
illustration and description. They are not intended to be
exhaustive or to limit the invention to the precise forms
disclosed, and obviously many modifications and variations are
possible in light of the above teachings. The exemplary embodiments
were chosen and described in order to explain certain principles of
the invention and their practical application, to thereby enable
others skilled in the art to make and utilize various exemplary
embodiments of the present invention, as well as various
alternatives and modifications thereof. It is intended that the
scope of the invention be defined by the Claims appended hereto and
their equivalents.
* * * * *