U.S. patent application number 15/152149 was filed with the patent office on 2016-11-17 for motor vehicle heat exchanger system.
This patent application is currently assigned to Benteler Automobiltechnik GmbH. The applicant listed for this patent is Benteler Automobiltechnik GmbH. Invention is credited to MAXIMILIAN BEYE, TOBIAS DUPMEIER, Julian Grenz, SVEN PRZYBYLSKI.
Application Number | 20160334170 15/152149 |
Document ID | / |
Family ID | 55968955 |
Filed Date | 2016-11-17 |
United States Patent
Application |
20160334170 |
Kind Code |
A1 |
Grenz; Julian ; et
al. |
November 17, 2016 |
MOTOR VEHICLE HEAT EXCHANGER SYSTEM
Abstract
A motor vehicle heat exchanger system with a closed circuit for
an operating medium includes an evaporator for evaporating the
operating medium and a condenser for condensing the vaporous
operating medium AM is provided. A reservoir for the liquid
operating medium is integrated between the condense and the
evaporator. Liquid operating medium is conducted from the reservoir
via a feed line into the evaporator. In addition the reservoir and
the evaporator are connected with each other via a compensation
line. Vapor which may form during operation of the motor vehicle
heat exchanger system on the liquid side of the evaporator can
escape through the compensation line thereby achieving a pressure
compensation.
Inventors: |
Grenz; Julian; (Delbruck,
DE) ; PRZYBYLSKI; SVEN; (Paderborn, DE) ;
BEYE; MAXIMILIAN; (Magdeburg, DE) ; DUPMEIER;
TOBIAS; (Paderborn, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Benteler Automobiltechnik GmbH |
33102 Paderborn |
|
DE |
|
|
Assignee: |
Benteler Automobiltechnik
GmbH
33102 Paderborn
DE
|
Family ID: |
55968955 |
Appl. No.: |
15/152149 |
Filed: |
May 11, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 2021/008 20130101;
Y02T 10/12 20130101; F02G 5/00 20130101; F28D 15/025 20130101; F28F
13/185 20130101; F25B 23/006 20130101; F28F 3/025 20130101; F01N
5/02 20130101; F28D 15/0266 20130101; Y02T 10/16 20130101; F28F
13/003 20130101; F28D 15/04 20130101; F28D 9/0037 20130101; F28D
21/0003 20130101; F28D 15/046 20130101 |
International
Class: |
F28D 15/02 20060101
F28D015/02; F28D 21/00 20060101 F28D021/00; F28D 15/04 20060101
F28D015/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 12, 2015 |
DE |
10 2015 107 442.7 |
Claims
1. A motor vehicle heat exchanger system with a closed circuit for
circulating an operating medium, said heat exchanger system
comprising: an evaporator for evaporating liquid operating medium
to vaporous operating medium; a condenser for condensing the
vaporous operating medium; and a reservoir for receiving the liquid
operating medium, said reservoir being arranged between the
condenser and the evaporator, wherein the reservoir and the
evaporator are connected with each other via a feed line for
conduction of liquid operating medium, and wherein the reservoir
and the evaporator are further connected with each other via a
compensation line.
2. The motor vehicle heat exchanger system of claim 1, wherein the
evaporator comprises at least one evaporator cassette, wherein a
capillary structure is arranged in the evaporator cassette and the
evaporator cassette has a liquid side and a vapor side and a vapor
collector.
3. The motor vehicle heat exchanger system of claim 2, wherein the
compensation line is connected with the liquid side of the at least
one evaporator cassette.
4. The motor vehicle heat exchanger system of claim 1, wherein the
compensation line is connected to the evaporator via a compensation
connection and the feed line is connected with the evaporator via a
feed connection, said compensation connection being positioned
above the feed connection.
5. The motor vehicle heat exchanger system of claim 2, wherein the
capillary structure is formed by a porous plate body made of a
sintered material.
6. The motor vehicle heat exchanger system of claim 1, wherein the
capillary structure has vapor grooves and/or vapor channels on the
vapor side.
7. The motor vehicle heat exchanger system of claim 1, wherein the
evaporator has at least two evaporator cassettes, and wherein a
channel is formed between the at least two evaporator
cassettes.
8. The motor vehicle heat exchanger system of claim 7, wherein the
channel is an exhaust gas channel.
9. The motor vehicle heat exchanger system of claim 7, further
comprising heat transfer elements provided in the channel.
10. The motor vehicle heat exchanger system of claim 2, wherein on
the vapor side of an evaporator cassette vapor grooves and/or vapor
channels are provided in the bottom of the housing of the
evaporator cassette.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the priority of German Patent
Application, Serial No. 10 2015 107 442.7, filed May 12, 2015,
pursuant to 35 U.S.C. 119(a)-(d), the content of which is
incorporated herein by reference in its entirety as if fully set
forth herein.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a motor vehicle heat
exchanger system.
[0003] The following discussion of related art is provided to
assist the reader in understanding the advantages of the invention,
and is not to be construed as an admission that this related art is
prior art to this invention.
[0004] The use of waste heat or lost thermal energy in motor
vehicles, for example of lost thermal energy in the exhaust gas of
the internal combustion engines of motor vehicles, offers several
possibilities to increase the efficiency of motor vehicles. In this
connection the use of waste heat for heating the passenger
compartment offers the possibility to dispense with additional
heating measures thereby reducing fuel consumption. The waste heat
can also be used for accelerating the warm-up of drive components
of a motor vehicle during startup. Hereby mechanical power loss and
with this motor load and consumption during the warm-up phase can
be reduced.
[0005] The recovery of waste heat generated during combustion
processes of the motor thus offers a great potential to safe fuel
and can contribute to increasing the comfort of driving and using a
motor vehicle.
[0006] The references EP 0 832 411 B1 or DE 696 06 296 T2 disclose
a method for transporting liquids in a micro fluid circuit system
with a capillary pump for transporting heat. In the circuit at
least one evaporator and a condenser and a container for receiving
a heat transmitting fluid or operating medium is provided. The
evaporator has an outlet, which is connected with the inlet of the
condenser via an evaporating line. An outlet of the condenser is
connected with the storage container. The evaporator contains an
evaporator body with a permeable material in order to evaporate the
operating medium by heat absorption and to generate a capillary
pump pressure in the interior of the circuit. The reservoir and the
evaporator are thermally isolated against each other and are
connected with t each other by a line. Hereby the container is
constructed so that it is held at a lower temperature than the
evaporator. This is intended to enable a heat exchange with a
minimal temperature difference between the heat source and the
condenser.
[0007] The reference U.S. Pat. No. 4,087,047 A or DE 25 23 645 A1
and also DE 38 06 418 C2 disclose proposals in which the cooling
water is to be heated with so called heat pipes in an accelerated
manner. Hereby conventional heat pipes are used, wherein the
evaporator region of the heat pipe is in contact with the exhaust
gas and the condenser part is in contact with the cooling circuit
of the motor. The heat pipes have at their wall a capillary
structure, which transports the operating medium from the condenser
back onto the evaporator zone.
[0008] Further a heat pipe of the circuit type is part of the state
of the art as disclosed in DE 10 2008 007 726 A1. This heat pipe is
intended to conduct heat from the exhaust gas to an air cooled
condenser. Via the condenser the air flowing into the driver
compartment is heated.
[0009] A loop heat pipe is an evacuated closed heat transport
system that is filled with operating medium. When using exhaust gas
heat by means of loop heat pipes (LHP) LHP evaporators are
integrated in to the exhaust gas line of motor vehicles. The
evaporator consists essentially of a housing an inner capillary
structure, a sealing and a cover. The sealing severs for
maintaining a pressure difference between liquid and gaseous
operating medium, which is generated by capillary forces in the
capillary structure.
[0010] The evaporation in the capillary structure is enabled by the
heat conductivity of the mostly metallic structure. At the same
time the capillary structure acts as a heat bridge to the
evaporator par in which the operating medium in a liquid state
meets the capillary structure. In this evaporator part the heat
bridge causes evaporation of the operating medium. This leads on
one hand to a reduction of the pressure difference between the
liquid part of the evaporator and the evaporation region. In
addition the vapor pressures through the connection line between
the reservoir and the evaporator, which impedes the supply of
liquid operating medium and is characterized by a rising of vapor
bubbles in the reservoir. At high heat input this effect can be so
strong that the return flow is not sufficient to prevent the
capillary structure from completely drying out. In this case the
circuit inside the loop heat pipe is interrupted and the heat
transport between the evaporator and the condenser comes to a
halt.
[0011] It would therefore be advantageous and desirable to provide
an improved motor vehicle heat exchanger system regarding its
applicability and to increase its efficiency.
SUMMARY OF THE INVENTION
[0012] According to one aspect of the present invention, a motor
vehicle heat exchanger system with a closed circuit for circulating
an operating medium, includes an evaporator for evaporating liquid
operating medium to vaporous operating medium; a condenser for
condensing the vaporous operating medium; and a reservoir for
receiving the liquid operating medium, wherein the reservoir is
arranged between the condenser and the evaporator, wherein the
reservoir and the evaporator are connected with each other via a
feed line for conduction of liquid operating medium, and wherein
the reservoir and the evaporator are further connected with each
other via a compensation line.
[0013] The motor vehicle heat exchanger system has a closed circuit
for an operating medium. In the circuit an evaporator is
integrated, the evaporator is in heat conducting contact with a
heat source of the motor vehicle. Particularly advantageously the
evaporator is integrated in the exhaust gas stream of the internal
combustion engine of the motor vehicle. This allows using the waste
heat of the hot exhaust gas. The exhaust gas conducted out of the
internal combustion engine of the motor vehicle is for this purpose
completely or partially conducted though an exhaust gas duct, in
the evaporator the operating medium is evaporated and form there
flows via a vapor line to a condenser arranged in the motor
vehicle. In the condenser a heat exchange with a user takes place,
wherein the vaporous operating medium is condensed and liquefied.
Via a return line the liquid operating medium is conducted into the
reservoir and from there it is conducted back into the evaporator
via the feed line.
[0014] The reservoir serves for storing operating medium and for
homogenizing circulation of the operating medium. The reservoir is
integrated between the condenser and the evaporator and connected
with these via fluid lines. Hereby the reservoir and the evaporator
are in contact with each other via a feed line for liquid
medium.
[0015] The additional compensation line between the liquid part or
the liquid side of the evaporator and the reservoir supports the
vapor discharge from the liquid side of the evaporator or supports
a pressure compensation from the evaporator toward the
reservoir.
[0016] According to another advantageous feature of the invention,
the evaporator includes at least one evaporator cassette, wherein
in the evaporator cassette a capillary structure is arranged. In
the evaporator cassette a liquid side and a vapor side are
separated from each other by the capillary structure. Further an
evaporator cassette has a vapor collector. in the vapor collector
the vaporous operating medium is collected and form there conducted
out of the condenser.
[0017] According to another advantageous feature of the invention,
the capillary structure is formed by a porous plate body.
Preferably the capillary structure is made of a sintered material.
In particular the capillary structure is metallic.
[0018] According to another advantageous feature of the invention,
the compensation line is connected with the liquid side of the
evaporator cassette.
[0019] According to another advantageous feature of the invention,
the compensation line is connected to the evaporator via a
compensation connection and the feed line is connected to the
evaporator via a feed connection. Hereby the compensation
connection is n particular positioned above the feed connection. In
this way the compensation connection is located in the motor
vehicle heat exchanger system higher than the feed connection. As a
consequence potential vapor, which may form on the liquid side,
flows due to the natural buoyancy in the direction toward the
compensation connection.
[0020] Liquid operating medium is conducted via the feed line
between the reservoir and the evaporator in the lower part of the
evaporator, whereas the vapor is discharged from the upper part of
the evaporator via the compensation line. As a result of this
arrangement the liquid operating medium pushes the vapor generated
on the liquid side upwards from where the vapor is discharged in
the direction of the reservoir via the compensation line. This
results in a forced direction for the vapor. A rising of vapor
bubbles through the feed line between the reservoir and the
evaporator is prevented. Particularly advantageously is hereby that
on the liquid side no large vapor bubbles or vapor regions are
generated. Such disadvantageous regions may lead to an overheating
of the operating medium and in critical cases to damage because
there the liquid operating medium with the corresponding cooling
effect is missing.
[0021] An evaporator cassette is preferably configured rectangular
and plate-shaped. In a simple construction the housing consists of
an evaporator cassette made of a housing shell, which is closed by
a lid. In the lid the required connections for the operating medium
as wells as for the compensation line are integrated. In the
interior of the evaporator cassette the capillary structure is
integrated which is also configured rectangular plate-shaped. This
configuration is advantageous in terms of manufacture. The same
applies to the required mounting space and to the weight of the
evaporator. In the capillary structure vapor grooves or vapor
channels are formed. Particularly preferably the vapor grooves or
vapor channels are provided on the vapor side of the capillary
structure. Alternatively or in addition vapor grooves or vapor
channels can also be formed in the housing of an evaporator
cassette namely on the vapor side in the bottom of the housing.
Such vapor grooves or vapor channels can be formed by embossments
in the bottom of the housing. Of course the vapor grooves or vapor
channels can also be formed by a material removing processing.
[0022] According to another advantageous feature of the invention,
the evaporator has at least two evaporator cassettes wherein
between the evaporator cassettes a channel for conducting a hot
fluid in particular an exhaust gas channel is formed. The heat
transfer form the hot fluid in particular from the exhaust gas into
the evaporator, is accomplished via heat transfer elements, for
example heat exchanger fins. As a result of the heat input the
operating medium evaporates inside the capillary structure and is
conducted through vapor grooves to a vapor collector and
subsequently through a vapor line to a condenser. In the condenser
the operating medium is liquefied by heat dissipation and flows via
a return line into the reservoir. Form the reservoir the liquid
operating medium flows via the feed line back to the
evaporator.
[0023] In the condenser of the motor vehicle heat exchanger system
according to the invention the vaporous operating medium, which
comes form the evaporator is condensed. For this the condenser is
integrated in a cooling fluid stream and is impinged with cooling
fluid, wherein the cooling fluid flows against the condenser is a
or flows around or through the condenser. In a configuration of the
motor vehicle heat exchanger system which is advantageous in praxis
the reservoir can be arranged in the cooling fluid stream and is
cooled by the cooling fluid stream. This measure contributes to
maintaining a low pressure level in the circuit.
BRIEF DESCRIPTION OF THE DRAWING
[0024] Other features and advantages of the present invention will
be more readily apparent upon reading the following description of
currently preferred exemplified embodiments of the invention with
reference to the accompanying drawing, in which:
[0025] FIG. 1 shows a technically simplified and schematized
longitudinal section through an evaporator cassette of a heat
exchanger of the motor vehicle heat exchanger system according to
the invention;
[0026] FIG. 2 shows the evaporator cassette of FIG. 1 with the
illustration of fluid flows; and
[0027] FIG. 3 shows a technically simplified illustration of a
motor vehicle heat exchanger system according to the invention with
the essential system components.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] Throughout all the Figures, same or corresponding elements
may generally be indicated by same reference numerals. These
depicted embodiments are to be understood as illustrative of the
invention and not as limiting in any way. It should also be
understood that the figures are not necessarily to scale and that
the embodiments are sometimes illustrated by graphic symbols,
phantom lines, diagrammatic representations and fragmentary views.
In certain instances, details which are not necessary for an
understanding of the present invention or which render other
details difficult to perceive may have been omitted.
[0029] A motor vehicle heat exchanger system has a closed circuit
for an operating medium AM and includes an evaporator 1 for
evaporating the operating medium AM and a condenser 2 for
condensing the vaporous operating medium AMd the operating medium
AM is in particular ethanol. Between the condenser 2 and the
evaporator 1 a reservoir 3 is provided. The evaporator is
integrated in the exhaust gas stream AG of an internal combustion
engine of a motor vehicle.
[0030] The evaporator 1 includes in the exemplary embodiment
according to FIG. 3 a total of two evaporator cassettes 4. FIGS. 1
and 2 show a technically simplified longitudinal sectional view of
an evaporator cassette 4.
[0031] The evaporator cassettes 4 are configured rectangular with
housing 5 made of a housing shell 6 and a cover 7. In the housing 5
of the evaporator cassettes 4 a respective capillary structure 8 is
arranged. The capillary structure 8 is formed by a porous plate
body made of a sintered material, in particular in metal basis. The
capillary structure 8 is aligned with the housing 5 and is sealed
against the cover 7 via spacers 9. The spacer 9 are formed by
gaskets.
[0032] The two evaporator cassettes 4 are arranged parallel to each
other and are oriented vertically. Between the evaporator cassettes
4 an exhaust gas channel 10 for hot exhaust gas Ag is formed. The
exhaust gas AG originates form the exhaust gas stream of the
internal combustion engine of the motor vehicle. This can be a
partial stream derived form the exhaust gas stream. In the exhaust
gas channel 10 heat transfer elements 11 for enlarging the heat
transfer surface are provided. The heat transfer elements 11 are
sheet metal lamellas that are oriented in longitudinal direction of
the evaporator 1, so called heat exchanger fins. The exhaust gas AG
flows though the exhaust gas channel 10. Hereby heat is transferred
from the exhaust gas AG to the evaporator cassettes 4 and the
operating medium AM. The heat flux is illustrated in FIG. 2 by the
arrows W. In FIG. 2 also the fluid flow of liquid operating medium
AM and vaporous operating medium AM is shown. For indicating the
aggregate state of the operating medium AM liquid operating medium
is designated AMf and vaporous operating medium AMd.
[0033] In an evaporator cassette 4 a liquid side 12 and a vapor
side 13 are separated by the capillary structure 8. On the liquid
side 12 a feed line 14 via a feed connection 15 for supplying
liquid operating medium AMf into the evaporator cassette 4 is
provided. Each evaporator cassette 4 further has a vapor collector
16. In the vapor collector 16 the respective operating medium AMd
evaporated in an evaporator cassette 4 is collected and conducted
in the circuit of the motor vehicle heat exchanger system to the
condenser 2 via a vapor outlet 17 and a vapor line 18.
[0034] The liquid operating medium AMf is distribute on the liquid
side 12 via the surface of the capillary structure 8. As a result
of heat transfer from the exhaust gas AG that flows through the
exhaust gas channel 10 the operating medium AM is evaporated in the
evaporator cassettes 4, the operating medium AM traverses the
capillary structure 8 form the liquid side 12 and transitions form
the liquid state into the vaporous state. The phase boundary
between liquid and vapor during operation of the evaporator 1
extends in the capillary structure 8, whereby a capillary pressure
is generated which causes and maintains the circuit of the
operating medium AM. On the vapor side 13 the vaporous operating
medium AMd flows through vapor grooves 19 until it enters the vapor
collector 16. The vaporous operating medium AMd is discharged form
the vapor collectors 16 via the vapor outlet 17 and the vapor line
18.
[0035] The operating medium AMf which has been liquefied in the
condenser 2 as a result of heat given off to a user is conducted
via a return line 20 into the reservoir 3. From the reservoir 3 the
liquid operating medium AMf reaches the evaporator 1 via the feed
line 14 and is conducted into the evaporator cassettes 4.
[0036] Between the evaporator 1 and the reservoir 3 a compensation
line 21 is additionally provided which connects the reservoir 3 and
the evaporator 1. Via the compensation line 21 pressure
compensation takes place between the evaporator 1 and the reservoir
3. This in particular allows air bubbles, which form on the liquid
side 12 of the evaporator, to escape.
[0037] FIG. 3 shows the fluid flow of liquid operating medium AMf
and vaporous operating medium AM in the circuit of the motor
vehicle heat exchanger system. Liquid operating medium AM is stored
in the reservoir 3 and is conducted via a respective feed line 14
to the evaporator 14. For supplying the two evaporator cassettes 4
the feed line 14 is divided into two line branches. Via the feed
connection 15 the liquid operating medium AM reaches the liquid
side 12 of the evaporator cassettes 4. Evaporated or vaporous
operating medium AMd exits from the evaporator cassettes 4 via the
vapor outlets 17 and is conducted to the condenser 2 via the vapor
line 18.
[0038] The compensation line 21 is also connected with the liquid
side 12 of an evaporator cassette 4 via the compensation connection
22. It can be seen that the compensation connection 22 is arranged
above the feed connection 15. The compensation connection 22 is
thus situated vertically above the feed connection 15. As a
consequence the liquid operating medium AMf is conducted via the
feed line 14 into the lower part of the evaporator 1 or the
evaporator cassettes 4 and evaporates as described above, wherein
the operating medium AM hereby traverses the capillary structure 8
from the liquid side 12 to the vapor side 13. When operating medium
AM evaporates in the liquid side 12 by heat bridge formation, the
vapor can be conducted out of the upper part of the evaporator 1 or
the evaporator cassettes 4 via the compensation line 21. The liquid
operating medium AM pushes the vapor generated on the liquid side
12 upwards which it is discharged via the compensation connection
21 and is conducted into the reservoir 3 through the compensation
line 21. The formation of vapor bubbles or vapor regions on the
liquid side 12 of an evaporator cassette 4 can thus be prevented or
counteracted.
[0039] What is claimed as new and desired to be protected by
Letters Patent is set forth in the appended claims and includes
equivalents of the elements recited therein:
* * * * *