U.S. patent application number 11/834064 was filed with the patent office on 2008-02-14 for cooling device for a motor vehicle.
This patent application is currently assigned to BEHR GMBH & CO. KG. Invention is credited to Uwe Blass, Ulrich Vollert.
Application Number | 20080035316 11/834064 |
Document ID | / |
Family ID | 38753224 |
Filed Date | 2008-02-14 |
United States Patent
Application |
20080035316 |
Kind Code |
A1 |
Blass; Uwe ; et al. |
February 14, 2008 |
COOLING DEVICE FOR A MOTOR VEHICLE
Abstract
The invention relates to a cooling device (1) for a motor
vehicle with a combustion engine (2) comprising a coolant radiator
(5) through which air can flow, an axial blower (3) which is
arranged behind the coolant radiator (5) in the airflow direction
(L), [and] a shroud (6), arranged between the coolant radiator (5)
and the axial blower (3), with a shroud ring (7) in which the axial
blower (3, 3b) is arranged so it can turn. It is proposed to widen
the shroud ring (7) on the air outflow side radially into a flow
guidance device (8).
Inventors: |
Blass; Uwe; (Moglingen,
DE) ; Vollert; Ulrich; (Stuttgart, DE) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
700 THIRTEENTH ST. NW, SUITE 300
WASHINGTON
DC
20005-3960
US
|
Assignee: |
BEHR GMBH & CO. KG
Stuttgart
DE
|
Family ID: |
38753224 |
Appl. No.: |
11/834064 |
Filed: |
August 6, 2007 |
Current U.S.
Class: |
165/121 ;
165/148 |
Current CPC
Class: |
F01P 5/06 20130101; F01P
11/10 20130101; F28F 9/002 20130101; F28D 2021/0094 20130101; F04D
29/526 20130101 |
Class at
Publication: |
165/121 ;
165/148 |
International
Class: |
F28D 1/00 20060101
F28D001/00; F28F 13/00 20060101 F28F013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 10, 2006 |
DE |
10 2006 037 641.2 |
Claims
1. A cooling device for a motor vehicle with a combustion engine,
comprising a coolant radiator through which air can flow, an axial
blower which is arranged behind the coolant radiator in the airflow
direction (L), a shroud with a shroud ring that is arranged between
the coolant radiator and the axial blower, with the axial blower
being arranged in the frame ring so that it can turn, wherein the
shroud ring is radially widened on the air outflow side into a flow
guidance device.
2. The cooling device according to claim 1, wherein the flow
guidance device has a surface that forms a flare angle .alpha. with
the axis (a) of the axial blower, where
.alpha..gtoreq.55.degree..
3. The cooling device according to claim 2, wherein the flow
guidance device has a conical surface.
4. The cooling device according to claim 2, wherein the flare angle
.alpha. of the flow guidance device, seen over the circumference of
the shroud ring, is variable.
5. The cooling device according to claim 1, wherein the axial
blower has an external diameter D.sub.L, and the flow guidance
device has an external diameter D.sub.A on the outflow side, where
the following relation applies: D.sub.A.gtoreq.1.1 D.sub.L.
6. The cooling device according to claim 1, wherein the axial
blower has blades that turn within the axial extent of the
cylindrical area of the shroud ring.
7. The cooling device according to claim 1, wherein the axial
blower has fan blades with a blade overhang (u) on the outflow
side, where the overhang extends in the axial direction of the flow
guidance device.
8. The cooling device according to claim 1, wherein, on the side
against which the air flows, the shroud ring has an inlet nozzle
and the axial blower has a shell, and in that an annular gap with a
180.degree. direction change is formed between the inlet nozzle and
the shell.
9. The cooling device according to claim 8, wherein a radially
external area of the inlet nozzle transitions into the shroud
ring.
10. The cooling device according to claim 8, wherein the shroud,
the inlet nozzle, the shroud ring, and the flow guidance device are
designed as one piece.
11. The cooling device according to claim 8, wherein the shell has
a downstream, diffuser-like widened area.
12. The cooling according to claim 1, wherein at least the shroud
ring having the flow guidance device is engine-mounted.
13. The cooling device according to claim 12, further comprising
flexible and/or movable sealing means for compensating relative
movement between the shroud and the coolant radiator.
14. The cooling device according to claim 1, wherein the axial
blower is driven by the combustion engine.
15. The cooling device of claim 2, wherein
.alpha..gtoreq..alpha..degree..
16. The cooling device of claim 4, wherein .alpha. has values
between .alpha..sub.1.gtoreq.55.degree. and
.alpha..sub.2.ltoreq.90.degree..
17. The cooling device of claim 5, wherein D.sub.A.gtoreq.1.5
D.sub.L.
18. The cooling device of claim 10, wherein the one piece is
injection molded.
19. The cooling device of claim 14, wherein the axial blower is
driven by a fluid friction clutch.
Description
[0001] The invention relates to a cooling device for a motor
vehicle according to the preamble of claim 1.
[0002] Known from the applicant's DE 33 04 297 C2 is a cooling
device for motor vehicles with an axial blower, which is
engine-mounted and can be driven by the combustion engine of the
motor vehicle. The axial blower sucks in air through a coolant
radiator, to the back side of which is attached a radiator shroud
for channeling the air flow. The axial blower has an axial blade
attachment with an external guide ring (shell), which projects
against the flow direction beyond the front edges of the blade, and
extends into an engine-mounted inlet nozzle. As a result of this
combination of an inlet nozzle and a projecting guide ring, an
annular gap with a 180.degree. direction change is created that
produces a strongly throttled gap air flow. The guide ring is
radially enlarged in its downstream area, and it can also
additionally have a diffuser part. Because of a strong throttling,
the axial blower has a semiaxial flow, which is supported, or
reinforced, by the enlarged area of the guide ring and diffuser
part. As a result of the incorporation of the axial blower in the
vicinity of the motor, recirculation of the exiting air flow can
occur in the known arrangement, i.e., a renewed aspiration through
the radiator can occur that detrimentally affects the cooling
capacity.
[0003] Known from DE 42 22 264 A1 is a cooling device for a motor
vehicle that has an electrofan, i.e., a fan that is driven by an
electromotor. In this known construction design, the electromotor
and the axial blower (axial fan) are attached by braces, a shroud
ring, and a radiator shroud on the radiator side. The shroud ring
has a cylindrical part in which the axial blower rotates, and a
diffuse, flaring surface which is connected to the cylindrical part
downstream of it. Other data regarding the design, the dimensions,
and the purpose of the diffuse flaring surface are included in the
patent. In accordance with the representation provided in the
drawing, the person skilled in the art will therefore start with a
conventional diffuser with a flare angle of approximately 7.degree.
relative the axial direction. This means that the outflow of the
air behind the axial blower is oriented axially, i.e., no
deflection occurred, only a deceleration of the flow.
[0004] The problem of the present invention is to improve the
blower characteristics of a cooling device of the type described in
the introduction, and also to prevent the recirculation of the air
flow exiting from the fan.
[0005] This problem is solved by the characteristics of Claim 1.
According to the invention, the shroud ring widens radially on the
side of the outflow into a funnel-shaped flow guidance device. The
flow exiting from the fan, which is a semiaxial or semiradial flow
(flow with an axial and with a radial component), is further
deflected by the flow guidance device outward, i.e., in the radial
direction. This prevents the outflow behind the fan from frontally
hitting the engine block and other units behind the fan, and
collecting there. As a result of the radial deflection of the flow,
a recirculation, i.e., a reentry of the air flow into the radiator,
is also prevented, which improves the cooling capacity.
[0006] Advantageous embodiments of the invention can be obtained
from the dependent claims. The radial widening of the flow guidance
device is characterized by a flare angle which is at least
55.degree., preferably 60.degree. and more, with respect to the
axial direction. The radial expansion can occur in one step, by
means of a conical surface with a flare angle, or in at least two
steps, by at least two successive connected conical surfaces with
increasing flare angles or in the shape of a flare or bell. As a
result, a relatively strong expansion occurs, which reinforces the
semiradial flow in the fan further in the radial direction. Thus a
relatively strong deflection is achieved in a relatively short
axial installation space. The flare angle .alpha. can also be
designed to be variable over the circumference, if the outflow
conditions behind the fan vary, for example, because of secondary
units arranged on the combustion engine.
[0007] The flow guidance device is advantageously characterized by
a maximum external diameter on the downstream end that is at least
1.1 times, preferably 1.15 times, that of the fan diameter. As a
result, a maximum deflection of the outflow can be achieved in the
installation space available in the vehicle.
[0008] The fan blades can either turn within the cylindrical area
of the shroud ring, or they can have a blade overhang on the
downstream side that extends into the widened area of the flow
guidance device. As a result, the advantage is achieved that the
semiaxial flow into the externally located blade areas or blade tip
areas is improved, and it contacts directly--without
separation--the internal wall of the flow guidance device; the flow
is stabilized.
[0009] To further improve the fan characteristics, a known inlet
nozzle is provided on the double shroud ring that works in
cooperation with a guide ring or shell that is attached to the
blade tip. As a result, an annular gap and consequently a gap flow
with a 180.degree. direction change is produced. The gap flow in
the annular gap is directed against the main axial flow in the fan,
and it sucks air out of the outflow area. In this context, it is
also advantageous that, as a result of the aspiration caused by the
gap flow, a greater deceleration is achieved in the outflow area
(the effect of boundary layer aspiration).
[0010] The semiaxial outflow and the radial deflection of the
outflow toward the exterior can be supported by a radially widening
shell of the fan, i.e., by a shell which widens like a diffuser.
The tendency for the flow to separate is thereby decreased.
[0011] According to an advantageous embodiment of the invention,
the shroud ring is engine-mounted, i.e., it is fixed to the block
of the combustion engine. As a result, relative motions are
generated between the shroud and the radiator and between the
shroud ring and the shroud, respectively. The relative movements
are compensated by flexible or movable sealing means in the form of
lips or folded bellows.
[0012] The axial blower is also engine-mounted, and it is driven by
the combustion engine preferably via a fluid friction clutch. As a
result, minimal gaps are formed between the shroud ring and the
blower blade tips or the blower shell.
[0013] Embodiments of the invention are represented in the drawing
and explained in greater detail below. In the drawing
[0014] FIG. 1 shows a cooling device according to the invention
with an engine-mounted axial blower, and a radiator,
[0015] FIG. 2 shows a modified embodiment of the axial blower
according to FIG. 1,
[0016] FIG. 3 shows an additional embodiment of the cooling device
with a ring fan and integrated inlet nozzle, and
[0017] FIG. 4 shows an additional embodiment of a flow guidance
device with a flare angle .alpha. which is variable over the
periphery.
[0018] FIG. 1 shows a cooling device 1 according to the invention
for a motor vehicle, which has an engine block 2 on which an axial
blower 3 is attached and positioned. The axial blower 3 has a fan
hub 3a with axial blade attachment 3b and a rotational axis a. The
fan hub 3a is attached to a fluid friction clutch--not shown--which
is driven via a belt drive system 4. (It is also possible to use a
direct drive via the crankshaft of the combustion engine.) On the
side of the axial blower 3 facing away from the engine block 2 is
arranged a coolant/air heat exchanger 5, hereafter called a
radiator, which is braced--not shown--against the body of the motor
vehicle (for example, the side rails). Relative movements between
the radiator 5 and the engine block 2 occur as a result. Air,
represented by an arrow L, flows through the radiator 5. On the
outflow side, a shroud 6, which is designed in the shape of a
bonnet, is connected to the radiator 5, and guides the airflow
exiting from the radiator 5 to the axial blower 3. The latter is
surrounded by a shroud ring 7, which is designed cylindrically on
its internal side, and which is connected, in the downstream
direction, to a funnel-shaped widening flow guidance device 8. The
shroud ring 7 and the flow guidance device 8 are designed as a unit
in the represented embodiment. Arranged on the upstream part of the
shroud ring 7 is an elastic lip 7a which lies against the shroud 6
and can slide on the latter. The shroud ring 7 is attached--not
shown--to the engine block 2, while the shroud 6 is attached via an
elastic fastening element 6a to the radiator 5. The fan 3, or its
blade attachment 3b, has an external diameter D.sub.L. The flow
guidance device 8, on its downstream end, has an external diameter
D.sub.A. The two diameters D.sub.A, D.sub.L, satisfy the following
inequality: 1.1.ltoreq.D.sub.A/D.sub.L.ltoreq.1.4, particularly
1.15.ltoreq.D.sub.A/D.sub.L. The flow guidance device 8 has a
conical surface 8a which forms an angle .alpha. with the axial
direction (rotation axis a), this angle characterizing the measure
of the radial widening of the guidance flow device 8. This
so-called flare angle .alpha. is chosen to be greater than
55.degree., preferably greater than 60.degree.. The geometry of the
flow guidance device 8 is determined using the two above-mentioned
dimensioning units D.sub.A/D.sub.L and the flare angle .alpha.. The
transition from the cylindrical area of the shroud ring 7 to the
conical area 8a is preferably rounded in form, i.e., it promotes
flow.
[0019] The flow guidance device 8, 8a according to the invention
has the effect that the air flow--represented by a dashed flow
arrow P--that exits from the fan 3b is deflected outward in the
radial direction. As a result, on the one hand, an accumulation of
the air flow in front of the engine block 2 is prevented, and on
the other hand a recirculation, i.e., a return flow in the
direction of the radiator inlet 5, is also prevented.
[0020] FIG. 2 shows a cooling device 9, similar to the cooling
device of 1 FIG. 1, except that it has an axial blower 10 which is
modified or axially offset with a hub 10a and an axial blade
attachment 10b. The blades 10b have a blade overhang u in the
airflow direction with respect to the cylindrical part of the frame
i.e., the blades 10b extend with their overhang u into the radially
widened conical area 8a of the flow guidance device 8. The course
of the semiaxial flow over the blades 10b, and the outflow in the
area of the flow guidance device 8 are represented by a dashed flow
arrow S. This variant with the blade overhang u promotes a low-loss
outflow with subsequent radial deflection, and stabilizes the
flow.
[0021] FIG. 3 shows, as an additional embodiment of the invention,
a cooling device 11 in which a shroud 12, a shroud ring 13, and a
flow guidance device 14 are formed as a single plastic
injection-molded piece. In addition, an inlet nozzle 15 is
overmolded in the inlet area of the shroud ring 13, as described in
a similar form in the state of the art mentioned in the
introduction. The axial blower 16 is designed as a so-called ring
fan, i.e., a shell or guide ring 17 is arranged on the
circumference of the blade 16b and is connected to the blade tips.
As is also known from the state of the art, the guide ring 17 has
an overhang on the inlet side that extends into the inlet nozzle
15. As a result, a 180.degree. direction change is achieved. The
guide ring 17 has a part 17b on the outflow side which is widened
conically and forms a transition to the adjoining flow guidance
device 14. An annular gap 18 is thus formed between the guide ring
17 and the shroud ring 13 which develops a gap flow opposite the
main flow in the fan. The inlet nozzle 15, in connection with the
guide ring 17, improves the flow conditions in the blade tip area,
reduces the noise level, and decreases the leakage flow. In
addition, the aspiration of the gap flow in the downstream area of
the fan results in a greater deceleration of the main flow and a
better application of the flow against the flow guidance device 14.
The gap flow thus has the known effect of aspiring a boundary
layer. For the rest, the cooling device 11 corresponds to the
cooling device 1 according to FIG. 1.
[0022] The injection molded part which consists of the shroud 12,
the shroud ring 13, the flow guidance device 14, and the inlet
nozzle 15, is connected by braces, which are not shown, to the
engine block 2. Therefore there are practically no relative
movements at all between the guide ring 17 and the shroud ring 13,
so that a minimal annular gap 18 can be achieved. However, an
elastic or movable fastening of the shroud 12 to the radiator 5 is
required, and it is preferably achieved using an elastic fastening
element 12a.
[0023] In contrast to the embodiments represented in the drawing,
which has a conical or cone-shaped surface 8a of the flow guidance
device 8, a bell- or flare-shaped form is also possible and within
the scope of the invention.
[0024] FIG. 4 shows, as an additional embodiment of the invention,
a cooling device 20 with a combustion engine 21 that has several
secondary units 22 in the front-end area for example, a coolant
pump and a generator that are connected by a belt drive to each
other. The front of the combustion engine 21 presents a relatively
jagged and irregular design due to the arrangement of the secondary
units 22. A driver cab 23 is arranged above the combustion engine
21, which closes off the motor space at the top. In front of the
secondary units 22 in the driving direction, an axial blower 3 and
a radiator 5, or a cooling module formed from several heat
exchangers, are/is arranged. Arranged between the radiator 5 and
the axial blower 3 is a shroud 24 with a shroud ring 25 in which
the axial blower 3 turns. Connected to the shroud ring 25 is a flow
guidance device 26 which, seen over the circumference of the shroud
ring 25, has a varying flare angle .alpha.: in the drawing, for
example, two different flare angles are represented, an upper flare
angle .alpha..sub.1 of approximately 90.degree., and a bottom flare
angle .alpha..sub.2 of approximately 55.degree.. The flow guidance
device 26 is thus adapted to the different outflow conditions to
the rear of the axial blower 3, where the conditions result from
the arrangement of the secondary elements 22. A low-resistance
outflow of the cooling air is achieved as a result of this variable
design of the flare angle .alpha. over the circumference.
* * * * *