U.S. patent application number 13/603464 was filed with the patent office on 2013-03-07 for refrigerating circuit for use in a motor vehicle.
This patent application is currently assigned to DR. Ing. h.c.F. Porsche Aktiengesellschaft. The applicant listed for this patent is Robert Fleischhacker, Bastian Freese, Thomas Tscheppe. Invention is credited to Robert Fleischhacker, Bastian Freese, Thomas Tscheppe.
Application Number | 20130055752 13/603464 |
Document ID | / |
Family ID | 47710422 |
Filed Date | 2013-03-07 |
United States Patent
Application |
20130055752 |
Kind Code |
A1 |
Fleischhacker; Robert ; et
al. |
March 7, 2013 |
REFRIGERATING CIRCUIT FOR USE IN A MOTOR VEHICLE
Abstract
A refrigerating circuit for use in a motor vehicle has a
refrigerant compressor (8) connected on the output side to a
pressure line (4) and on the input side to a suction line (6). The
refrigerating circuit has at least one condenser (10), at least one
regulated expansion valve (14), at least one evaporator (16) and at
least one inner heat exchanger (12). The regulated expansion valve
(14) has a temperature t.sub.E in a detection zone (20) of the
suction line (6) as a controlled variable. The detection zone (20)
for the regulated expansion valve (14) is arranged at the output of
the inner heat exchanger (12).
Inventors: |
Fleischhacker; Robert;
(Magstadt, DE) ; Tscheppe; Thomas; (Oetigheim,
DE) ; Freese; Bastian; (Ostfildern, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fleischhacker; Robert
Tscheppe; Thomas
Freese; Bastian |
Magstadt
Oetigheim
Ostfildern |
|
DE
DE
DE |
|
|
Assignee: |
DR. Ing. h.c.F. Porsche
Aktiengesellschaft
Stuttgart
DE
|
Family ID: |
47710422 |
Appl. No.: |
13/603464 |
Filed: |
September 5, 2012 |
Current U.S.
Class: |
62/498 |
Current CPC
Class: |
B60H 2001/3291 20130101;
F25B 43/00 20130101; F25B 40/00 20130101; F25B 2600/2513 20130101;
F25B 40/06 20130101; F25B 41/00 20130101; F25B 41/062 20130101;
F25B 2341/0683 20130101 |
Class at
Publication: |
62/498 |
International
Class: |
F25B 1/00 20060101
F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2011 |
DE |
10 2011 053 256.0 |
Claims
1. A refrigerating circuit for use in a motor vehicle, comprising:
a refrigerant compressor with an output side connected to a
pressure line and an input side connected to a suction line; at
least one condenser; at least one regulated expansion valve; at
least one evaporator; and at least one inner heat exchanger,
wherein the regulated expansion valve has a temperature t.sub.E in
a detection zone of the suction line as a controlled variable, the
detection zone for the regulated expansion valve being arranged at
an output of the inner heat exchanger.
2. The refrigerating circuit of claim 1, wherein the regulated
expansion valve is a thermostatic expansion valve connected to one
of the outlets of the inner heat exchanger by a control line that
is part of the suction line.
3. The refrigerating circuit of claim 1, wherein the regulated
expansion valve is a thermostatic expansion valve with a detector
in the detection zone.
4. A refrigerating circuit for use in a motor vehicle, comprising:
a refrigerant compressor with an output side connected to a
pressure line and an input side connected to a suction line; a
condenser communicating with the pressure line; a regulated
expansion valve communicating with the suction line; an evaporator
communicating with the regulated expansion valve; an inner heat
exchanger having a pressure-side inlet communicating with the
condenser via the pressure line, a pressure-side outlet
communicating with the pressure-side inlet and with the regulated
expansion valve, a suction-side inlet communicating with the
evaporator and a suction side outlet communicating with the
suction-side inlet and with the regulated expansion valve; and a
detection zone at the suction-side outlet of the inner heat
exchanger and controlling the regulated expansion valve in
accordance with a temperature t.sub.E in a detection zone of the
suction line, thereby adjusting a mass flow rate of the refrigerant
through the inner heat exchanger.
5. The refrigerating circuit of claim 4, wherein the regulated
expansion valve is a thermostatic expansion valve connected to one
of the outlets of the inner heat exchanger by a control line that
is part of the suction line.
6. The refrigerating circuit of claim 4, wherein the regulated
expansion valve is a thermostatic expansion valve with a detector
arranged in the detection zone.
7. A refrigerating circuit for use in a motor vehicle, comprising:
a refrigerant compressor; a condenser; a regulated expansion valve;
an evaporator; an inner heat exchanger; a pressure line extending
from an output side of the refrigerant compressor and passing
through the condenser, through the inner heat exchanger and to the
regulated expansion valve; a suction line extending from the
regulated expansion valve, through the evaporator, through the
inner heat exchanger, back through the regulated expansion valve
and to an input side of the refrigerant compressor; and a control
means at a suction side output of the inner heat exchanger for
controlling the regulated expansion valve and thereby controlling
flow of refrigerant through the inner heat exchanger so that the
refrigerant flowing through the evaporator is in a wet vapor phase
and so that only gaseous refrigerant is input to the refrigerant
compressor.
8. The refrigerating circuit of claim 7, wherein the regulated
expansion valve a thermostatic expansion valve connected to one of
the outlets of the inner heat exchanger by a control line that is
part of the suction line.
9. The refrigerating circuit of claim 8, wherein the regulated
expansion valve is a thermostatic expansion valve with a detector
arranged in the detection zone.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 USC 119 to German
Patent Appl. No. 10 2011 053 256.0 filed on Sep. 5, 2011, the
entire disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention.
[0003] The invention relates to a refrigerating circuit for use in
a motor vehicle.
[0004] 2. Description of the Related Art.
[0005] Refrigerating circuits for motor vehicles are well known. In
the simplest type of structure of a refrigerating circuit of this
kind, a pressure line runs from the output of the compressor,
through the condenser, to the input of the expansion valve. The
pressure is lowered in the expansion valve, and therefore the
suction line is connected to the output of the expansion valve,
leading through the evaporator and ending at the input of the
compressor. The compressor changes the state of the refrigerant in
respect of pressure and temperature. In this case, the temperature
at the compressor outlet is higher than the condensing temperature
in the condenser since the vaporous refrigerant is highly
superheated. The refrigerant is still in a highly superheated state
at the condenser inlet. The condenser releases heat to the
environment, and therefore the refrigerant is in a liquid state at
the outlet of the condenser. The refrigerant has a particular
condensing temperature and a particular condensing pressure, that
are referred to as the saturated temperature and the saturated
pressure. The liquid is supercooled at the condenser outlet, and
hence achieves a temperature lower than the saturation temperature.
There is a further change in the state of the refrigerant in the
expansion valve. More particularly, the pressure reduction
performed in the expansion valve causes the refrigerant to begin to
boil. As a result, there is a mixture of refrigerant in the liquid
and the vapor state at the compressor inlet. The refrigerant
absorbs heat in the evaporator and therefore is in the vapor state
at the evaporator outlet and in this way is sucked in by the
compressor in the suction line. The refrigerant at the evaporator
output must be in a superheated gaseous state to avoid damage to
the compressor. A regulated expansion valve may be used to ensure
that the refrigerant is in the superheated state at the output of
the evaporator. In this case, the expansion valve has the
temperature t.sub.E at the output of the evaporator as the
controlled variable. If the refrigerant is then in a highly
superheated state, i.e. at a high temperature t.sub.E, too little
refrigerant is injected into the evaporator, and the mass flow rate
of the refrigerant may increase. Conversely, the valve opening
becomes smaller as the detector temperature falls in relation to
the temperature in the superheated state at the evaporator output.
An inner heat exchanger may be used in the pressure and the suction
line to improve efficiency of a refrigerating circuit of this kind.
The inner heat exchanger passes the cooled refrigerant under high
pressure to the expansion valve, and the superheated expanded
refrigerant is passed to the compressor. As a result, the
refrigerant to be condensed is supercooled further so that the
proportion of liquid in the refrigerant after expansion rises and
hence more liquid refrigerant is available for evaporation. The
inner heat exchanger thereby increases the refrigerating capacity
and also the efficiency of the refrigerating circuit.
[0006] Improved efficiency can lead to a reduction in the power
consumption of the compressor, thereby achieving reductions in fuel
consumption and emissions. The reduced power requirement also may
be enable use of a smaller compressor.
[0007] It is therefore the object of the invention to provide a
more efficient refrigerating circuit for use in a motor
vehicle.
SUMMARY OF THE INVENTION
[0008] The invention relates to a refrigerating circuit with a
regulated expansion valve that has a detection zone arranged at the
suction-side output of the inner heat exchanger. This arrangement
functions as a control means for ensuring that only gaseous
refrigerant is present at the compressor input, while enabling the
refrigerant to still be in the mixed/vapor state at the evaporator
output. Only after passing through the inner heat exchanger is the
refrigerant in the gaseous state. In this way, the refrigerant can
be supercooled to a greater extent, thereby making it possible to
improve heat release in the evaporator, this in turn having a
positive effect on efficiency. Moreover, the refrigerating circuit
of the invention ensures that the cooling capacity of the
refrigerant is distributed uniformly over the entire evaporator
since the refrigerant is in the wet vapor phase in the entire
evaporator zone.
[0009] The regulated expansion valve preferably is a thermostatic
expansion valve connected by a control line that is part of the
suction line to the output of the inner heat exchanger.
[0010] The regulated expansion valve preferably is a thermostatic
expansion valve with a detector arrangement with a detector in the
detection zone.
[0011] The invention is explained in greater detail below with
reference to the drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows a schematic refrigerant circuit according to
the invention.
[0013] FIG. 2 shows a simplified pressure-enthalpy diagram of a
refrigerating circuit in accordance with FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] The refrigerating circuit of FIG. 1 has a pressure line 4
and a suction line 6. The pressure line 4 begins at the output of a
compressor 8. The compressor 8 compresses the refrigerant to a
condensing pressure P.sub.V, which is indicated by a change of
state A in FIG. 2. The refrigerant is passed at the condensing
pressure P.sub.V to a condenser 10, in which the refrigerant
releases heat so that the refrigerant is liquid at the output of
the condenser 10 and has a condensing temperature t.sub.V. This
change of state is denoted by B in FIG. 2.
[0015] The refrigerant is passed from the condenser 10 to an inner
heat exchanger 12, in which the refrigerant in the pressure line 4
releases heat to the refrigerant in the suction line 6, as
indicated by the change of state C in the pressure-enthalpy diagram
of FIG. 2. The refrigerant is passed from the inner heat exchanger
12 at the pressure P.sub.V to the regulated expansion valve 14. The
control of the expansion valve 14 is explained in greater detail
below after the description of the complete refrigerating
circuit.
[0016] There is a change in the state of the refrigerant in the
expansion valve 14 so that the pressure is reduced to P.sub.0, and
the temperature decreases to a temperature t.sub.0. The refrigerant
then begins to boil and is then in what is referred to as the wet
vapor region indicated by the change of state D in FIG. 2.
[0017] The suction line 6 begins at the output of the expansion
valve 14 and passes the refrigerant to the evaporator 16 where the
refrigerant is evaporated to a greater extent and absorbs heat. In
contrast to the prior art, this takes place at a constant
temperature t.sub.0 and a constant pressure P.sub.0. The
refrigerant is still in the wet vapor region at the output 17 of
the evaporator 16 and not, as is customary in the prior art, in the
superheated state, in which the temperature would already be
elevated. The state of heat absorption in the evaporator is
indicated by E in FIG. 2. The refrigerant then passes through the
inner heat exchanger 12, absorbing heat from the refrigerant in the
pressure line 4 and thus being superheated, as indicated by the
change of state F in FIG. 2. The refrigerant then passes via the
suction line 6, through the expansion valve 14, to the input of the
compressor 8, thereby completing the refrigerating circuit 2.
[0018] The part of the suction line 6 that leads from the output of
the inner heat exchanger 12 to the expansion valve 14 is a control
line 18 for the regulated expansion valve 14. The expansion valve
14, is known per se, and is constructed to open at a temperature
t.sub.E=t.sub.0+t.sub.x, with the opening and hence the mass flow
rate of the refrigerant increasing as tx rises.
[0019] The suction line 6 also could be routed directly from the
inner heat exchanger 12 to the compressor 8, with a suitable
detector arrangement being provided at the output of the inner heat
exchanger 12. The arrangement transmits the temperature t.sub.E at
the output of the heat exchanger to the regulated expansion valve
14 in a suitable manner.
* * * * *