U.S. patent application number 12/067145 was filed with the patent office on 2008-10-23 for arrangement for cooling an internal combustion engine of a motor vehicle, in particular cooling module.
Invention is credited to Martin Harich, Eberhard Pantow, Ulrich Vollert.
Application Number | 20080257286 12/067145 |
Document ID | / |
Family ID | 37507840 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080257286 |
Kind Code |
A1 |
Harich; Martin ; et
al. |
October 23, 2008 |
Arrangement for Cooling an Internal Combustion Engine of a Motor
Vehicle, in Particular Cooling Module
Abstract
The invention relates to an arrangement for cooling an internal
combustion engine of a motor vehicle, in particular a cooling
module (1), comprising an air-guiding device (7, 6) for air
guidance having an overall flow cross section, at least two heat
exchangers (2, 3) for cooling fluid flows, an air feed device (4,
4a, 4b) and a device which is arranged in the air flow for
regulating the air mass flow. It is proposed that the air mass flow
in a part cross section of the overall cross section can be
regulated by the device.
Inventors: |
Harich; Martin;
(Ludwigsburg, DE) ; Pantow; Eberhard; (Moglingen,
DE) ; Vollert; Ulrich; (Stuttgart, DE) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Family ID: |
37507840 |
Appl. No.: |
12/067145 |
Filed: |
September 18, 2006 |
PCT Filed: |
September 18, 2006 |
PCT NO: |
PCT/EP06/09057 |
371 Date: |
July 3, 2008 |
Current U.S.
Class: |
123/41.12 |
Current CPC
Class: |
F01P 5/06 20130101; F01P
7/10 20130101; F04D 27/009 20130101; Y02T 10/88 20130101; B60K
11/085 20130101; F01P 11/10 20130101 |
Class at
Publication: |
123/41.12 |
International
Class: |
F01P 7/02 20060101
F01P007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2005 |
DE |
10 2005 044 559.4 |
Claims
1. An arrangement for cooling an internal combustion engine of a
motor vehicle, in particular a cooling module, comprising an
air-conducting device for air guidance having a overall flow cross
section, at least one heat exchanger for cooling a fluid flow, an
air-conveying device, and a device, disposed in the air flow, for
regulating the air-mass flow, wherein the air-mass flow in at least
a partial cross section of the overall flow cross section can be
regulated by the air-regulating device.
2. The arrangement as claimed in claim 1, wherein at least two heat
exchangers are arranged side by side in the air flow and can be
parallelly impinged upon by the air flow.
3. The arrangement as claimed in claim 1, wherein, to the partial
cross section there is assigned a partial air flow, by which a heat
exchanger can be impinged upon.
4. The arrangement as claimed in claim 3, wherein the partial air
flow can be sectioned off by a partition running in the air flow
direction.
5. The arrangement as claimed in claim 1, wherein the
air-regulating device is disposed in front of the heat exchangers
in the air flow direction.
6. The arrangement as claimed in claim 1, wherein the
air-regulating device is disposed behind the heat exchanger in the
air flow direction.
7. The arrangement as claimed in claim 6, wherein in that the
air-regulating device is disposed in a frame.
8. The arrangement as claimed in claim 7, wherein in the frame
there is disposed a cooling-air blower.
9. The arrangement as claimed in claim 1, wherein the
air-regulating device is configured as a shutter.
10. The arrangement as claimed in claim 9, wherein between the
shutter and the cooling-air blower there is disposed a swivel flap,
by which a partial air flow flowing through the heat exchanger can
be shut off or separated.
11. The arrangement as claimed in claim 10, wherein one of the heat
exchangers is configured as a coolant cooler for cooling an
internal combustion engine.
12. The arrangement as claimed in claim 10 wherein, one of the heat
exchangers is configured as a charge-air cooler.
13. An arrangement for cooling an internal combustion engine of a
motor vehicle, in particular a cooling module, comprising an
air-conducting device for air guidance, at least one heat exchanger
for cooling a fluid flow, and an air-conveying device, wherein the
air-conducting device has a frame with variable intake cross
section, which can be altered between a maximum (Amax) and a
minimum (Amin), and the differential area between maximal and
minimal intake cross section can be utilized at least partially as
a ram air opening.
14. The arrangement as claimed in claim 13, wherein the intake
cross section can be altered in steps.
15. The arrangement as claimed in claim 13, wherein the intake
cross section can be altered steplessly.
16. The arrangement as claimed in claim 13, wherein, the frame has
at least one flap for adjusting the intake cross section.
17. The arrangement as claimed in claim 16, wherein the at least
one flap is disposed pivotably in the rear wall of the frame.
18. The arrangement as claimed in claim 17, wherein the at least
one flap is disposed in the outer regions of the frame rear
wall.
19. The arrangement as claimed in claim 16, wherein at least two
flaps are provided, which can be pivoted independently of each
other, in particular one after the other.
20. The arrangement as claimed in claim 16, wherein the at least
one flap is configured as a folding flap and is integrated in the
rear wall of the frame.
21. The arrangement as claimed in claim 16, wherein the air flow
which can be sucked up by the fan behind the heat exchangers can be
sealed off from the heat exchangers by the at least one flap.
22. The arrangement as claimed in claim 13, wherein the frame has a
foldable rear wall having a displaceable separating and sealing
element, which delimits the intake cross section and seals off the
suction flow.
Description
[0001] The invention relates to the cooling of an internal
combustion engine of a motor vehicle, in particular a cooling
module according to the preamble to claim 1 and to the coordinate
Patent claim 13.
[0002] Cooling modules are known--in the form of pre-assembled
structural units, which are preferably disposed and fastened in the
front engine compartment of a motor vehicle. The structural unit or
cooling module comprises various cooling components and components
of an air-conditioning system, inter alia various heat exchangers
such as coolant coolers, charge-air coolers, oil coolers or
refrigerant condensers. In addition, one or more cooling-air
blowers, comprising fan and drive motor, can also form a
constituent part of the cooling module. All cooling components are
held together by a frame-like structure, a so-called module
carrier, and supported in the vehicle. All of the heat exchangers
are cooled by a cooling-air flow, i.e. ambient air, which is
generated by ram pressure or by the cooling-air blower. The air
flow flowing through the cooling module generates an air
resistance, which increases the c.sub.w-value of the vehicle.
Depending on the arrangement of the heat exchangers in the cooling
module, these are impinged upon more or less strongly by the
cooling-air flow, which does not always meet the requirements of
the respective cooling demand. The cooling demand for the
individual heat exchangers is very varied and depends on the
respective load states. The cooling demand is usually regulated by
an adjustment of the fluid flows in the heat exchangers, whilst the
air-mass flow (flow rate) is not generally altered or is adapted to
the respective cooling demand of the individual heat
exchangers.
[0003] Through EP 1 431 698 A2, it is known to regulate the
air-mass flow as a whole, a shutter being disposed in the air flow,
which shutter extends over the whole of the air flow cross section.
Such a shutter can also be used to control a cooling-air flow
through the engine compartment for cooling of the motor and
gearbox.
[0004] DE 197 19 792 B4 of the Applicant has disclosed a method and
a device for regulating the cooling air temperature in a motor
vehicle, wherein a shutter is likewise disposed in the cooling-air
flow, which shutter determines the flow rate of the whole of the
cooling-air flow which is branched off from the ram pressure. The
share of removal of the cooling air flow from the ram air
influences the vehicle resistance: the more the shutter is opened,
the stronger is the increase in air resistance, thereby increasing
the total energy consumption.
[0005] Shutters are known in various forms and different
arrangements, for example as louvred or slatted shutters, disclosed
by DE 196 52 398 A1 and DE 197 15 352 A1 of the Applicant. In
addition, so-called winding shutters are known, in which, the
cooler and/or the condenser end face can be covered by a cloth
which can be wound up and down (DE 35 22 591 A1 of the Applicant).
Shutters are also used for sound insulation.
[0006] A drawback with these known solutions is that in each case
only the entire air flow, which impinges upon all the heat
exchangers of the cooling module, is regulatable.
[0007] The object of the invention is to improve a cooling
arrangement of the type stated in the introduction such that a
differentiated regulation of the air-mass flow, in particular an
air flow regulation for individual heat exchangers of the cooling
module, is possible, and an adaptation to the variable ram pressure
is achievable.
[0008] This object is achieved by virtue of the features of Patent
claim 1. Advantageous embodiments of the invention derive from the
sub-claims.
[0009] According to the invention, it is firstly provided that the
shutter disposed in the air flow regulates only a partial cross
section, i.e. a partial air flow. It is thus possible to regulate
the air flow rate purposefully for individual heat exchangers or a
specific heat exchanger. The advantage of an improved output
regulation for the individual heat exchangers of the cooling module
is thus achieved, because, in addition to the regulation of the
fluid flow, i.e. of the medium to be cooled, the cooling medium
itself, the cooling air, can also be regulated. Depending on the
configuration of the shutter, this can be done in steps or
steplessly from fully open to fully closed, so that it is possible,
for example, no longer to impinge upon selected heat exchangers in
specific operating states with cooling air at all. This prevents
the heat exchanger in question from not being undercooled or cooled
right down. Advantageously, viewed in the air flow direction, the
shutter can be disposed both in front of and behind the heat
exchanger(s). It can further be provided that in the air flow there
is disposed (in the air flow direction) a partition, which sections
off one or more partial air flows assigned to specific heat
exchangers. These partial air flows are regulated in their flow
rate by a shutter or a multipart shutter.
[0010] According to an advantageous embodiment of the invention,
the fan for conveying the cooling air, and the shutter, are
respectively disposed behind the heat exchangers and in a frame
adjoining the cooling module. In a further advantageous embodiment
of the invention, between the fan and the shutter there can then be
provided a swivel flap for separating the air flows or for
partitioning off an air flow. This yields the advantage that the
air flow, on the one hand, with closed shutter, is restricted and,
on the other hand, with closed shutter and swivelled-out separating
flap, is fully cut off. Such a solution is advantageous, for
example, for a coolant cooler at low external temperatures, since a
total cooling of the cooler is thus prevented. It is thus also no
longer necessary to reduce the fluid or coolant flow rate in the
heat exchanger or coolant cooler in the event of reduced cooling
demand, or to heavily reduce it. Finally, when the shutter is
restricted or closed, the advantage of a reduced vehicle resistance
is obtained, thereby lowering the fuel consumption.
[0011] The object of the invention is also achieved by virtue of
the features of the coordinated Patent claim 13--advantageous
embodiments of the invention derive from the subordinate
sub-claims.
[0012] According to the invention, a frame with variable geometry,
i.e. with a variable intake cross section for the fan and with
variable cross section for ram air openings, is provided. The
alteration of the intake cross section is preferably achieved by
one or more pivotable flaps, which, in particular, simultaneously
control the ram air openings. As a result of this variable geometry
of the frame, on the one hand an adaptation of the working point of
the fan to the various operating conditions such as idling, uphill
travel and high-speed travel is achieved, and, on the other hand,
an increase in the total air-mass flow is obtained. The fan thus
operates at higher efficiency and the cooling output of the cooling
module is improved.
[0013] In an advantageous embodiment of the invention, the
alteration of the intake cross section can be effected in steps,
preferably by means of flaps, or steplessly, preferably with a
folding flap or a foldable frame rear wall.
[0014] The flap or flaps are preferably horizontal, vertical,
angled or arc-shaped and are preferably arranged distributed around
a fan opening in the frame, the fan opening in all cases being
arranged centrically or eccentrically in the, in particular,
right-angled frame.
[0015] Illustrative embodiments of the invention are represented in
the drawing and are described in greater detail below, wherein:
[0016] FIG. 1 shows a cooling module with shutter in a first
setting (shutter open),
[0017] FIG. 2 shows the cooling module in a second setting (shutter
closed),
[0018] FIG. 3 shows the cooling module in a third setting (shutter
closed and flap in blocking position),
[0019] FIG. 4 shows the cooling module in a fourth setting (shutter
open and flap in separating position),
[0020] FIG. 5 shows a cooling module with variable frame geometry
(first setting),
[0021] FIG. 6 shows the cooling module according to FIG. 5 in a
second setting,
[0022] FIG. 7 shows the cooling module according to FIG. 5 in a
third setting,
[0023] FIG. 8 shows the cooling module according to FIG. 5 in a
fourth setting,
[0024] FIG. 9 shows a modified illustrative embodiment of a cooling
module with variable frame geometry (first setting),
[0025] FIG. 10 shows the cooling module according to FIG. 9 in a
second setting,
[0026] FIG. 11 shows the cooling module according to FIG. 9 in a
third setting,
[0027] FIG. 12 shows a further illustrative embodiment of a cooling
module with variable frame geometry,
[0028] FIG. 13 shows a further illustrative embodiment of a cooling
module with folding flap,
[0029] FIG. 14 shows a further illustrative embodiment of a cooling
module with foldable frame rear wall,
[0030] FIG. 15,
15a, 15b show fan and resistance characteristic curves according to
the prior art, and
[0031] FIG. 15c shows fan and resistance characteristic curves for
the inventive cooling module with variable frame geometry.
[0032] FIG. 1 shows a cooling module 1, comprising a coolant cooler
2 and a charge-air cooler 3, a cooling-air blower 4 and a shutter
5. The cooling components 2, 3, 4, 5 are received by a surround or
frame 6, represented only schematically, which also receives the
cooling-air blower 4, comprising a fan 4a and an electric motor 4b,
as well as the shutter 5, which is here configured as a louvred
shutter, comprising individual louvres or slats 5a. The coolant
cooler 2 and the charge-air cooler 3 are flowed against by cooling
air, represented by the arrows L1, L2; they are arranged side by
side or one above the other in the air flow direction and are
therefore parallelly impinged upon by the air flow. The air flow is
fed via an air-conducting device 7 in the form of an air flow duct,
the whole of the cooling module 1 being disposed in the front
engine compartment (not represented) of a motor vehicle. Between
the cooling-air blower 4 and the shutter 5 there is disposed a
pivotable flap 8, which can be fastened to the frame 6 in a
non-represented manner.
[0033] In the represented position of open shutter 5 and vertically
disposed flap 8, a maximal air-mass flow, created by ram pressure
in high-speed travel of the motor vehicle, can flow through the
cooling module, in particular the coolant cooler 2 and the
charge-air cooler 3. The air flow L2 flowing through the coolant
cooler 2 leaves the shutter 5 as the air flow L4, and the air flow
L1 flowing through the charge-air cooler 3 leaves behind the fan 4a
as the air flow L3, the respective air-mass flow not necessarily
having to be maintained past the vertically disposed flap 8 (L2=L4
and L1=L3) due to possible equalizing flows. When the fan is
switched off, a maximal cooling effect can thus be obtained for
both heat exchangers.
[0034] FIG. 2 shows the cooling module 1 according to FIG. 1 with
closed shutter 5. For identical parts, identical reference symbols
are used. The total air flow which enters the air-conducting device
7 is divided into a partial air flow L1, which flows through the
charge-air cooler 3, and a partial flow L2, which flows through the
coolant cooler 2. The air flow L2 leaving the coolant cooler 2 is
deflected upwards owing to the closed shutter 5 and is conveyed
outwards by the fan 4a as part of the air flow L5. The mass flow L5
corresponds to the sum of the partial air flows L1 and L2. In this
position, a maximal air-mass flow L5 during running of the fan 4a
can be obtained without ram pressure support, the air outlet cross
section being reduced as a result of the closed shutter 5.
[0035] FIG. 3 shows the cooling module 1 with closed shutter 5 and
horizontally disposed flap 8'. The air flow which passes through
the cooling module 1 is represented by an entry arrow L1 and by an
exit arrow L5, only the charge-air cooler 3 being flowed through by
air. The coolant cooler 2 is partitioned off on the air side by the
flap 8', acting as a partition, the shutter 5 simultaneously being
closed, so that no through-flow with cooling air is possible. The
flap position 8' represented horizontally in the drawing lies level
with the interstice between the coolant cooler 2 and the charge-air
cooler 3 and thus conducts the discharged charge-air flow through
the fan 4a. The represented position is advantageous, particularly
given a lack of cooling demand of the coolant cooler 2, i.e. at low
external temperatures, for example. A total cooling of the coolant
cooler and too great a lowering of the coolant temperature are
thereby prevented.
[0036] FIG. 4 shows the cooling module 1 with horizontally disposed
flap 8' and open shutter 5. As a result of this configuration, a
strict separation of the two incoming air flows L1, L2 into a fan
discharge flow L3 and an air flow L4 leaving the shutter 5 is made.
The cooling of the coolant cooler 2 is thus determined by the
vehicle speed or the ram pressure, whilst the cooling of the
charge-air cooler 3 is determined by the air flow L3 conveyed by
the fan 4a and supported by ram pressure.
[0037] The cooling module represented in the drawings is a
preferred illustrative embodiment--modifications are possible. For
example, additional or other heat exchangers can be provided.
Furthermore, the shutter can be disposed in front of the heat
exchangers in the air flow direction. In addition, the flap 8 can
be disposed as a partition in front of the heat exchangers in the
air flow direction and can divide the total air flow into partial
air flows or flow paths, which are assigned to the individual heat
exchangers. A purposeful regulation of the air-mass flow can thus
also be realized for individual heat exchangers, i.e.
selectively.
[0038] FIG. 5 shows a further illustrative embodiment of the
invention for a cooling module 9 having an air-conducting device 7
for the entry of cooling air, a coolant cooler 2 and a charge-air
cooler 3, which are disposed one above the other or side by side
and are parallelly impinged upon by the air flow, represented by
the arrows L. The two heat exchangers 2, 3 are accommodated and
fastened in a frame 10 with variable geometry. The frame 10 has a
rear wall 10a, which receives the cooling blower 4, comprising fan
4a and motor 4b. In the rear wall 10a there are provided, outside
the cross section of the fan 4a, two ram air openings 11, 12, which
can be controlled by pivotable flaps 13, 14. In the represented
position of the flaps 13, 14, i.e. in the horizontal setting or in
the air flow direction, both ram air openings 11, 12 are open, so
that from both openings 11, 12 there is respectively discharged an
air-mass flow V.sup...sub..kappa., which is determined by the ram
pressure prevailing in front of the heat exchangers 2, 3. The
intake cross section of the fan 4a is reduced by this flap setting
to a minimum A.sub.min. The air-mass flow conveyed by the fan 4a
and sucked up within the flaps 13, 14 is represented by an arrow
V.sup...sub.L. The represented configuration is advantageous in
high-speed travel of the motor vehicle and permits a maximal mass
flow through both heat exchangers 2, 3 or the cooling module, the
fan 4a being at the working point, i.e. it can supply a hydraulic
energy to the air flow sucked up and conveyed by it.
[0039] FIG. 6 shows the cooling module 9 according to FIG. 5 with
an altered flap setting: the upper flap 14 is pivoted into a
vertical setting in the drawing and thus closes the upper ram air
opening 12. The lower flap 13, on the other hand, is in a
horizontal setting and thus frees the ram air opening 11, from
which an air-mass flow V.sup...sub.K is discharged. The intake
cross section of the fan 4a is thus reduced to an intermediate
cross section A.sub.z or widened relative to the cross section
A.sub.min according to FIG. 5. This flap configuration is
advantageous for uphill travel, a maximal mass flow being conveyed
through the charge-air cooler 3. Here too, the fan 4a is at its
working point and can build up a pressure gradient.
[0040] FIG. 7 shows the cooling module 9 with an altered flap
configuration. The flaps 13, 14 are both in the closing position,
i.e. the ram air openings 11, 12 are closed, so that the fan frame
10 has its maximal intake cross section A.sub.max, which
corresponds to the downstream end face of the two heat exchangers
2, 3. This configuration is particularly advantageous when the
vehicle is stationary, i.e. without ram pressure: the fan 4a is at
the working point and conveys a maximal air-mass flow V.sup...sub.L
through both heat exchangers 2, 3 or the cooling module.
[0041] FIG. 8 shows the cooling module 9 with the flap 13 in the
closed and the flap 14 in the open setting, so that the upper ram
air opening 12 is open and permits an air-mass flow V.sup...sub.K
induced by ram pressure. The intake cross section A.sub.Z
corresponds to that in FIG. 6, with the difference that the coolant
cooler 2 is here fully impinged upon by the air flow. This
configuration is advantageous for uphill travel, with a maximal
air-mass flow through the coolant cooler 2 and reduced mass flow
through the charge-air cooler 3. Here, too, the fan 4a is at its
working point.
[0042] As shown by the various flap settings in FIGS. 5 to 8, the
cooling module 9 has a "variable frame geometry", i.e. the air
intake cross section and the cross section of the ram air openings
are adjustable; in their horizontal position, the flaps
respectively seal with their front edges against the rear side of
the heat exchanger network.
[0043] FIG. 9 shows a further illustrative embodiment of the
invention, namely a cooling module 15 with a block 16 of various
heat exchangers (not represented in detail), for example coolant
cooler, charge-air cooler, refrigerant condenser, oil cooler, inter
alia. The block 16 has an end face 16a, through which the air flow,
represented by the arrow L, enters, as well as an air outlet face
16b corresponding to the end face 16a. The block 16 is accommodated
in a frame 17, which has a rear wall 17a containing a fan 4a. In
the upper part of the rear wall 17a in the drawing, two mutually
adjacent ram air openings 18, 19 are provided, which are
respectively controllable by a swivel flap 20, 21. In the
represented horizontal position of the flaps 20, 21, the ram air
openings 18, 19 are freed, so that a ram air flow, represented by
the arrows V.sup...sub.K, is discharged. The flaps 20, 21 bear with
their upstream edges against the rear side 16b of the block 16 and
thus effect a sealing and a separation of the air flows conveyed,
on the one hand, by the fan 4a and, on the other hand, by the ram
pressure. The represented position of the flaps 20, 21 is
advantageous in high-speed travel and produces a maximal air-mass
flow through the cooling module 15, the fan 4a being at the working
point.
[0044] FIG. 10 shows the cooling module 15 according to FIG. 9 with
an altered flap setting. The outer flap 20 is in horizontal and the
inner flap 21 in roughly vertical setting, so that only the outer
ram air opening 18 is open and admits a ram-pressure-induced air
flow V.sup...sub.K. The intake cross section of the fan 4a thus has
an intermediate setting A.sub.z, which lies between the maximal and
the minimal intake cross section. The flap 20, with its front edge,
seals off the intake flow from the rear side 16b of the module
block 16. The represented position of the flaps is advantageous for
uphill travel, i.e. at lower ram pressure, and allows a maximal
air-mass flow through the module 16, made up of the fan flow
V.sup...sub.L and the ram air flow V.sup...sub.K.
[0045] FIG. 11 shows the cooling module 15 with a third flap
setting, namely with closed flaps 20, 21. The intake cross section
of the fan 4a is thus widened to the maximal cross section
A.sub.max and corresponds to the rear-side end face 16b of the
block 16. The represented closing position of the flaps 20, 21 is
advantageous when the vehicle is stationary, i.e. without ram
pressure--a maximal air-mass flow V.sup...sub.L is obtained through
the block 16, which is conveyed solely by the fan 4a. The fan 4a is
at the working point. The three represented flap positions
according to FIGS. 9, 10 and 11 show the variable frame geometry in
a step-by-step alteration from the minimal intake cross section
A.sub.min via the intermediate cross section A.sub.z to the maximal
intake cross section A.sub.max. At each operating point, i.e. in
high-speed travel and when the vehicle is stationary, the fan
operates at the working point at a relatively high efficiency.
[0046] FIG. 12 shows the cooling module 15 with a velocity
distribution v over the end face of the module block 16, which is
made up of a downstream-situated coolant cooler 22, an
upstream-situated charge-air cooler 23 and an engine oil cooler 24
disposed beside the charge-air cooler 23. The engine oil cooler 24
has an end face 24a and the charge-air cooler 23 has an end face
23a. The end face 24a roughly corresponds to the cross section of
the two ram air openings 18, 19, and the end face 23a to the intake
cross section of the fan 4a. The velocity distribution v over the
whole of the module end face is represented for the maximal speed
of the vehicle. Owing to the open ram air openings 18, 19, over the
end face 24a of the engine oil cooler 24 the velocity V.sub.K is
obtained, whilst over the end face 23a of the charge-air cooler 23
an increased velocity V.sub.L is established. This is conditioned
by the increase in energy acquired by the mass flow of the fan 4a
operating at the working point. In high-speed travel, i.e. when the
cooling output requirement of the charge-air cooler is increased,
the charge-air cooler 23 thus acquires an increased cooling
air-mass flow. As can be seen from the different velocity
distribution, the flow paths for the two mutually adjacent heat
exchangers 23, 24 are simultaneously divided, which latter can thus
be regulated with respect to their cooling output by an adapted
air-mass flow.
[0047] FIG. 13 shows as a further illustrative embodiment of the
invention a cooling module 25 with variable frame geometry in the
form of a so-called folding flap 26, which is integrated in the
rear wall of the frame. A module block 27 is adjoined by a frame
rear wall 28, in which the fan 4a rotates. The folding flap 26 is
integrated in the frame rear wall 28 in such a way that, as a
result of different foldings, different intake cross sections for
the fan 4a and, at the same time, different cross sections for the
ram air openings are freed. In the drawing, three settings 26a
(dashed), 26b (dotted) and 26c (solid) are represented. The setting
26c is characterized by a minimal intake cross section A.sub.c for
the fan 4a and a maximal ram air opening. The setting 26b of the
folding flap 26 produces a medium intake cross section A.sub.b and
a ram air opening of medium cross section. In the setting 26a, the
frame rear wall 28 is fully closed in the rearward direction, i.e.
the air intake cross section A.sub.a is maximal, and the whole of
the air flow sucked up through the module block 27 is conveyed by
the fan 4a. As in the previous illustrative embodiments, the
folding flap 26 here too, with its upstream edge, seals the air
flow against the rear side of the module block 27. Between the
represented positions 26a, 26b, 26c, intermediate settings are
possible, so that, all in all, a continuous, i.e. stepless
adjustment of the intake cross section, combined with a
corresponding alteration of the ram air opening, is possible. For
the various operating points, idling, uphill travel and high-speed
travel, it is thereby ensured that the fan operates at the working
point and an increased air-mass flow is obtained.
[0048] FIG. 14 shows as a further illustrative embodiment of the
invention a cooling module 29 with a module block 30 comprising
various components (not represented) and a variable frame geometry
in the form of a foldable rear wall 31, which also receives the fan
4a. The frame rear wall 31 can be folded transversely to the air
flow direction in the manner of a bellows and has at its free end a
separating and sealing element 32, which is displaceable likewise
transversely to the air flow direction L. The separating and
sealing element has a front sealing edge 32a, which slides on the
air outlet face 30a of the module block 30 and thus effects a
sealing of the air flow sucked up by the fan 4a. Outside the
sealing and separating element 32, i.e. on the side facing away
from the fan 4a, a ram air opening 33 is created, which allows a
ram air flow V.sup...sub.K. The foldable frame rear wall 31, in
conjunction with the sealing and separating element 32, allows a
stepless adjustment of the fan intake cross section and of the ram
air opening 33. At variance with the represented illustrative
embodiment, another, equivalent configuration of the frame rear
wall is also possible, for example as a roller or winding shutter
or in the form of foldable flaps according to the prior art.
[0049] FIG. 15 shows a diagram representing a fan characteristic
curve LKL (solid) and a resistance characteristic curve WKL,
wherein the static pressure .DELTA.PST is plotted over the air-mass
flow V.sup...sub.L. The point of intersection of the resistance
characteristic curve and the fan characteristic curve is the
working point, which is denoted by AP. The diagram shows a
resistance characteristic curve without ram pressure support. The
fan conveys at the working point a volume flow illustrated with
V.sup...sub.L. At the same time, at the working point, a positive
.DELTA.P is generated.
[0050] FIG. 15a shows a fan characteristic curve LKL and a
resistance characteristic curve WKL with ram pressure support, i.e.
relative to FIG. 15, the resistance characteristic curve WKL is
lowered into the negative range; similarly, the working point AP is
in the negative pressure range, i.e. the fan is "blown over" by the
ram pressure and can no longer supply energy to the air-mass flow.
The right side of FIG. 15a shows the corresponding cooling module
with module block 34, fan frame 35 and fan 36. The arrows v
represent the flow velocity of the air in the module block 34, i.e.
a homogeneous distribution, if the flow from the cooler to the fan
is assumed, by way of simplification, to be ideally free from
loss.
[0051] FIG. 15b shows a further fan characteristic curve LKL and
two different resistance characteristic curves, represented by
different symbols (squares and triangles). The right-hand part of
FIG. 15b shows the associated cooling module with block 34, frame
35, fan 36, as well as with ram pressure flaps 37 in the rear wall
of the frame 35. The steeper resistance characteristic curve WKL
relates to that part of the module block 34 which is flowed through
by the ram air flow V.sup..K. The flatter resistance characteristic
curve WKL relates to the lower part of the module block 34, which
is flowed through by the fan flow V.sup...sub.L. A dotted flow
filament curve 38 represents the dividing line between ram air flow
and fan flow. A total air-mass flow
V.sup...sub.ges=V.sup...sub.L+V.sup...sub.K is obtained. The fan
flow and the ram air flow thus add together to form the overall
flow. The point of intersection of the flatter resistance
characteristic curve WKL with the fan characteristic curve, i.e.
the working point AP, lies at a static pressure of 0, i.e. the fan
adds no energy to the air flow. FIGS. 15, 15a, 15b describe the
known prior art.
[0052] FIG. 15c shows, in contrast, the working method of the
invention for a module block 39 adjoined by a frame 40 with
variable geometry, i.e. with an intake cross section adjustable for
the fan 41. The module block 39 is divided by a separating and
sealing element 40a of the frame 40 into two sub-blocks, a lower
sub-block 39a and an upper sub-block 39b, and is sealed towards the
rear. The sub-block 39a is flowed through by a fan flow
V.sup...sub.L, which, supported by the ram pressure, is conveyed by
the fan 41. The upper sub-block 39b is flowed through by a
ram-pressure-induced bypass flow V.sup...sub.K, a lower flow
velocity for the sub-block 39b than for the sub-block 39a,
represented by the different length of the arrows v, being
obtained. The diagram arranged on the left in FIG. 15c shows a fan
characteristic curve LKL and two somewhat differing resistance
characteristic curves WKL, the upper resistance characteristic
curve (squares) applying to the upper sub-block 39b and the lower
one (triangles) to the lower sub-block 39a. The corresponding point
of intersection with the fan characteristic curve LKL is the
working point AP of the fan 41, which generates a fan flow
V.sup...sub.L. It can be seen from the diagram that the working
point AP lies in the positive pressure range, i.e. the fan supplies
energy to the flow. Due to the ram pressure of the vehicle, for the
upper sub-block 39 the bypass flow V.sup...sub.K as the point of
intersection of the upper resistance characteristic curve WKL with
the abscissa (.DELTA.P=0) is obtained. Both mass flows
V.sup...sub.K and V.sup...sub.L add together to form a total
air-mass flow V.sup...sub.ges, which is greater than the overall
flow in the prior art, represented by way of comparison in FIG.
15b. As a result of the variable frame geometry according to the
invention, an adaptation of the cooling module to the respective
operating conditions (idling, uphill travel, high-speed travel) can
be achieved in such a way that the fan operates at the working
point and, at the same time, an increase occurs in the total mass
flow.
* * * * *