U.S. patent application number 11/293105 was filed with the patent office on 2006-06-08 for vehicle air conditioning systems comprising refrigerant recovery vessels and methods for operating such systems.
Invention is credited to Yuuichi Matsumoto, Kenichi Suzuki, Masato Tsuboi.
Application Number | 20060117791 11/293105 |
Document ID | / |
Family ID | 35965988 |
Filed Date | 2006-06-08 |
United States Patent
Application |
20060117791 |
Kind Code |
A1 |
Suzuki; Kenichi ; et
al. |
June 8, 2006 |
Vehicle air conditioning systems comprising refrigerant recovery
vessels and methods for operating such systems
Abstract
An air conditioning system for a vehicle including a vapor
compression-type refrigerating cycle and using combustible
refrigerant includes a refrigerant recovery vessel in communication
with a gas-liquid separator and which of recovers the combustible
refrigerant by the communication with the gas-liquid separator, and
a valve which controls the communication between the refrigerant
recovery vessel and the gas-liquid separator in response to an
external signal. When combustible refrigerant is used as
refrigerant of a vapor compression-type, refrigerating cycle,
leakage of the refrigerant may be reduced, minimized, or
eliminated, and the recovery of the refrigerant may be carried out
readily and efficiently without requiring significant changes to
the system configuration.
Inventors: |
Suzuki; Kenichi;
(Takasaki-shi, JP) ; Tsuboi; Masato; (Isesaki-shi,
JP) ; Matsumoto; Yuuichi; (Isesaki-shi, JP) |
Correspondence
Address: |
BAKER BOTTS LLP;C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300
1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Family ID: |
35965988 |
Appl. No.: |
11/293105 |
Filed: |
December 5, 2005 |
Current U.S.
Class: |
62/512 |
Current CPC
Class: |
F25B 45/00 20130101;
B60H 1/00978 20130101; F25B 2700/19 20130101; F25B 2500/222
20130101; F25B 2400/16 20130101; B60H 1/3225 20130101; B60H 1/3217
20130101; F25B 2400/12 20130101 |
Class at
Publication: |
062/512 |
International
Class: |
F25B 43/00 20060101
F25B043/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2004 |
JP |
2004-352399 |
Claims
1. An air conditioning system for vehicles comprising a vapor
compression-type, refrigerating cycle, which uses combustible
refrigerant and comprises a gas-liquid separator, comprising; a
refrigerant recovery vessel in communication with said gas-liquid
separator and which recovers said combustible refrigerant in said
refrigerating cycle by the communication with said gas-liquid
separator; and a valve which controls the communication between
said refrigerant recovery vessel and said gas-liquid separator in
response to an external signal.
2. The air conditioning system of claim 1, wherein said gas-liquid
separator and said refrigerant recovery vessel are integral to each
other.
3. The air conditioning system of claim 2, wherein said valve is
integral with said gas-liquid separator and said refrigerant
recovery vessel.
4. The air conditioning system of claim 1, wherein a communication
path for communicating between said gas-liquid separator and said
refrigerant recovery vessel is disposed at a position outside of
said gas-liquid separator and said refrigerant recovery vessel, and
said valve is disposed in said communication path.
5. The air conditioning system of claim 1, wherein a time period
for recovering refrigerant by opening said valve is set at a
predetermined time period, and after expiration of said
predetermined time period, recovered refrigerant is enclosed by
closing said valve.
6. The air conditioning system of claim 1, further comprising a
pressure detecting device, which detects a pressure in said
refrigerant recovery vessel or in said gas-liquid separator, and
when refrigerant is recovered by opening said valve, said valve is
closed in accordance with a detected pressure by said pressure
detecting device.
7. The air conditioning system of claim 6, wherein said valve is
closed when a detected pressure by of said pressure detecting
device equals a predetermined pressure.
8. The air conditioning system of claim 1, further comprising a
vehicle collision detection device, which detects or predicts a
vehicle collision, and when the vehicle collision is detected or
predicted by said vehicle collision detection device, refrigerant
in said gas-liquid separator is recovered into said refrigerant
recovery vessel by opening said valve.
9. The air conditioning system of claim 1, further comprising a
refrigerant leakage detection device, which detects a leakage of
refrigerant in said refrigerating cycle, and when the refrigerant
leakage is detected by said refrigerant leakage detection device,
refrigerant in said gas-liquid separator is recovered into said
refrigerant recovery vessel by opening said valve.
10. The air conditioning system of claim 1, wherein, when
refrigerant in said gas-liquid separator is recovered into said
refrigerant recovery vessel by opening said valve, a main
controller stops a compressor provided in said refrigerating
cycle.
11. The air conditioning system of claim 1, wherein said valve is a
valve driven by an electromagnetic solenoid and said normally,
closed-type valve is opened when said electromagnetic solenoid is
energized.
12. A method for controlling leakage of refrigerant in an air
conditioning system for vehicles comprising a gas-liquid separator,
a refrigerant recovery vessel, and a selectively openable
communication path therebetween, said method comprising the steps
of: preselecting a predetermined parameter for stopping refrigerant
recovery; detecting a leakage of refrigerant within a refrigerant
circuit of said air conditioning system; opening said communication
path between said liquid-gas separator and said refrigerant
recovery vessel; and closing said communication path when a
measured parameter equals or exceeds said predetermined
parameter.
13. The method of claim 12, wherein said predetermined parameter is
a predetermined time period during which said communication path is
open.
14. The method of claim 12, wherein said predetermined parameter is
a predetermined pressure within said refrigerant recovery vessel,
such that said communication path is open when an pressure measured
within said refrigerant recovery vessel is less than said
predetermined pressure.
15. The method of claim 12, wherein said air conditioning system
comprises a compressor, and the method further comprises the step
of stopping said compressor when said communication path is
open.
16. A method for controlling leakage of combustible refrigerant in
an air conditioning system for vehicles comprising a gas-liquid
separator, a refrigerant recovery vessel, and a selectively
openable communication path therebetween, said method comprising
the steps of: preselecting a predetermined parameter for stopping
refrigerant recovery; detecting or predicting a vehicle collision;
opening said communication path between said liquid-gas separator
and said refrigerant recovery vessel; and closing said
communication path when a measured parameter equals or exceeds said
predetermined parameter.
17. The method of claim 16, wherein said predetermined parameter is
a predetermined time period during which said communication path is
open.
18. The method of claim 16, wherein said predetermined parameter is
a predetermined pressure within said refrigerant recovery vessel,
such that said communication path is open when a pressure measured
within said refrigerant recovery vessel is less than said
predetermined pressure.
19. The method of claim 16, wherein said air conditioning system
comprises a compressor and the method further comprises the step of
stopping said compressor when said communication path is open.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to vehicle air conditioning
systems including a vapor compression-type, refrigerating cycle and
using combustible refrigerant, and, more specifically, to vehicle
air conditioning systems having a mechanism which recovers
refrigerant from the refrigerating cycle into a refrigerant
recovery vessel, as needed.
[0003] 2. Description of Related Art
[0004] In a known, vehicle air conditioning system, for example, in
which Freon.RTM. refrigerant, commercially available from E.I.
DuPont De Nemours and Co., of Wilmington Del. USA, such as HFC 134a
refrigerant, is used as the refrigerant for a vapor
compression-type refrigerating cycle, even if the refrigerant
leaks, because it is incombustible, there is little or no risk of
fire or explosion. Generally, such leaks are not considered to
create significant risks.
[0005] Recently, in order to deal with global environmental
concerns, much attention has been paid to the use of a vapor
compression-type, refrigerating cycle using refrigerant having a
low, heat coefficient. As a possible low heat coefficient
refrigerant, natural system refrigerants, such as CO.sub.2 and
combustible refrigerants have been proposed. Nevertheless, in a
known air conditioning system for vehicles, in which refrigerant in
a vapor compression-type, refrigerating cycle is changed to
combustible refrigerant, if the refrigerant leaks, there may be
some risk of fire or explosion because the refrigerant is
combustible, and, therefore, it is considered preferable to take
measures to reduce, minimize, or eliminate the conditions favorable
to such risks.
[0006] Although it does not relate to an air conditioning system
for vehicles, a structure is known wherein a vessel is provided for
recovering combustible refrigerant via the opening and closing
operation of an electromagnetic valve of a vapor compression-type,
refrigerating cycle using combustible refrigerant. See Japanese
Patent Application No. JP-A-2000-171130 ("JP'130"). In the
structure described in JP'130, however, because a pipe diverges
from a refrigerant pipe between an expansion valve and an
evaporator, and because a refrigerant recovery vessel is connected
to the divergent pipe, even if this structure is applied to an air
conditioning system for vehicles, a design change or alteration of
the system would be required and is not easily applied. Further, it
may not always be possible to efficiently recover refrigerant by
extracting combustible refrigerant from the pipe provided between
an expansion valve and an evaporator.
SUMMARY OF THE INVENTION
[0007] Accordingly, a need has arisen for an air conditioning
system for vehicles which may recover refrigerant while reducing,
minimizing, or eliminating leakage of the refrigerant and which may
recover the refrigerant readily and efficiently without requiring
significant changes to the system configuration, when combustible
refrigerant is used as the refrigerant in a vapor compression-type,
refrigerating cycle.
[0008] To achieve the foregoing and other objects, an air
conditioning system for vehicles comprising a vapor
compression-type refrigerating cycle, which uses combustible
refrigerant and comprises a gas-liquid separator, according to the
present invention, comprises a refrigerant recovery vessel in
communication with the gas-liquid separator and which recovers
combustible refrigerant in the refrigerating cycle by the
communication with the gas-liquid separator. Further, the system
comprises a valve which controls the communication between the
refrigerant recovery vessel and said gas-liquid separator in
response to an external signal.
[0009] In this air conditioning system, it is preferred that the
gas-liquid separator and the refrigerant recovery vessel are
integral to each other. Further, the valve may be integral with the
gas-liquid separator and the refrigerant recovery vessel.
Alternatively, a communication path for communicating between the
gas-liquid separator and the refrigerant recovery vessel may be
disposed at a position outside of the gas-liquid separator and the
refrigerant recovery vessel, and the valve is disposed in the
communication path.
[0010] Various structures may be employed to control refrigerant
recovery. For example, a structure may be employed wherein a time
period for recovering refrigerant by opening the valve is set at a
predetermined time period, and after expiration of the
predetermined time period, recovered refrigerant is enclosed by
closing the valve. Further, a structure may be employed wherein a
pressure detecting device detects a vessel pressure in the
refrigerant recovery vessel or a separator pressure in the
gas-liquid separator, when refrigerant is recovered by opening the
valve, the valve then is closed in accordance with a detected
pressure by the pressure detecting device. In this structure, when
refrigerant has been recovered by opening the valve, the valve then
may be closed when a detected pressure by the pressure detecting
device equals or exceeds a predetermined pressure. Further, a
structure may be employed wherein a vehicle collision detection
device detects or predicts a vehicle collision, and when the
vehicle collision is detected or predicted by the vehicle collision
detection device, refrigerant in the gas-liquid separator is
recovered into the refrigerant recovery vessel by opening the
valve. Still further, a structure may be employed wherein a
refrigerant leakage detection device detects a leakage of
refrigerant in the refrigerating cycle, and when the refrigerant
leakage is detected by the refrigerant leakage detection device,
refrigerant in the gas-liquid separator is recovered into the
refrigerant recovery vessel by opening the valve.
[0011] In addition, it is preferred that, when refrigerant in the
gas-liquid separator is recovered into the refrigerant recovery
vessel by opening the valve, a compressor provided in the
refrigerating cycle is stopped.
[0012] Moreover, it is preferred that the valve is a valve driven
by an electromagnetic solenoid and that the normally, closed-type
valve is opened when the electromagnetic solenoid is energized.
[0013] In another embodiment, a method is provided for controlling
leakage of refrigerant in an air conditioning system for vehicles
comprising a gas-liquid separator, a refrigerant recovery vessel,
and a selectively openable communication path therebetween. The
method comprises the steps of: preselecting a predetermined
parameter for stopping refrigerant recovery; detecting a leakage of
refrigerant within a refrigerant circuit of the air conditioning
system; opening said communication path between said liquid-gas
separator and the refrigerant recovery vessel; and closing the
communication path when a measured parameter equals or exceeds the
predetermined parameter.
[0014] In still another embodiment, a method is provided for
controlling leakage of combustible refrigerant in an air
conditioning system for vehicles comprising a gas-liquid separator,
a refrigerant recovery vessel, and a selectively openable
communication path therebetween. The method comprising the steps
of: preselecting a predetermined parameter for stopping refrigerant
recovery; detecting or predicting a vehicle collision; opening the
communication path between the liquid-gas separator and the
refrigerant recovery vessel; and closing said communication path
when a measured parameter equals or exceeds the predetermined
parameter. In these methods, the predetermined parameter may be a
predetermined time period during which the communication path is
open or a predetermined pressure within the refrigerant recovery
vessel, such that the communication path is open when a pressure
measured within the refrigerant recovery vessel is less than the
predetermined pressure. Further, the air conditioning system may
comprise a compressor, and these methods may comprise the step of
stopping the compressor when the communication path is open.
[0015] In the air conditioning system for vehicles according to the
present invention, which air conditioning system uses combustible
refrigerant as the refrigerant in a vapor compression-type,
refrigerating cycle, the refrigerant may be recovered readily and
efficiently without requiring significant changes to the system
configuration and substantially at a specification of the present
system, and leakage of the combustible refrigerant to outside may
be reduced, minimized, or eliminated. Therefore, the risk of fire
or explosion due to leakage of combustible refrigerant may be
reduced, minimized, or eliminated.
[0016] Other objects, features, and advantages of the present
invention will be apparent to persons of ordinary skill in the art
from the following detailed description of preferred embodiments of
the present invention and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For a more complete understanding of the present invention,
the needs satisfied thereby, and the objects, features, and
advantages thereof, reference now is made to the following
description taken in connection with the accompanying drawings.
[0018] FIG. 1 is a schematic diagram of an air conditioning system
for vehicles according to an embodiment of the present
invention.
[0019] FIG. 2 is a vertical, cross-sectional view of a refrigerant
recovery vessel integral with a gas-liquid separator in the system
depicted in FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0020] FIG. 1 depicts an air conditioning system 100 for vehicles
according to an embodiment of the present invention. FIG. 2 depicts
a refrigerant recovery vessel 8 integral with a gas-liquid
separator 7 used in system 100 depicted in FIG. 1. In FIG. 1, air
conditioning system 100 comprises a vapor compression-type,
refrigerating cycle 1 using combustible refrigerant. In vapor
compression-type, refrigerating cycle 1, a compressor 3 is driven
by an engine (or motor) 2 of a vehicle, which is a variable
displacement compressor adapted to alter or adjust its displacement
or a fixed displacement compressor. The driving force from engine 2
is transmitted, for example, via an electromagnetic clutch (not
shown), and the ON/OFF operation of the electromagnetic clutch is
controlled via a clutch controller 4. Compressor 3 may form part of
a refrigerating cycle regardless of the presence or absence of such
a clutch, and further, the control method of displacement (e.g.,
adjusting the swash plate angle or varying compressor speed) is not
particularly limited. Refrigerant compressed to a relatively high
temperature and pressure by compressor 3 is cooled at a condenser 6
having a fan 5 by exchanging heat with outside air, and the
refrigerant is condensed and substantially liquefied. Refrigerant
exiting condenser 6 is separated into a gaseous-phase portion and a
liquid-phase portion by gas-liquid separator 7, and in this
embodiment, as described below, gas-liquid separator 7 is integral
with refrigerant recovery vessel 8. An electronic solenoid 10 and a
pressure sensor 11 are provided to an integral, refrigerant
recovery vessel and gas-liquid separator device 9. The liquid
refrigerant separated by gas-liquid separator 7 is reduced in
pressure and expanded by an expansion valve 12, and, thereafter, is
sent to an evaporator 13 as a cooling medium, and heat is exchanged
with air sent through an air duct 14. The refrigerant evaporated in
evaporator 13 then is drawn into compressor 3, and again
compressed. The evaporator exit temperature is controlled by a
displacement control signal sent to compressor 3 or by ON/OFF
control of the electromagnetic clutch via clutch controller 4.
[0021] A blower 15 is disposed in air duct 14 through which air
passes for air conditioning of a vehicle interior. An inside air
introduction port 16 and an outside air introduction port 17 are
provided at an entrance of air duct 14, and a switching damper 18
controls the amount of air drawn from both ports 16 and 17, and the
drawn air then is sent toward evaporator 13 by blower 15. A portion
of this drawn air having passed through evaporator 13 then is sent
to heater 19 disposed downstream of evaporator 13. The amount of
air having passed through evaporator 13 and through heater 19 may
be adjusted by an air mixing damper 20 to vary the amount of air
having passed through evaporator 13 and bypassed heater 19. The
degree to which air mixing damper 20 is opened may be adjusted by
an air mixing damper actuator 21. In this embodiment, at the exit
side of evaporator 13, an evaporator exit air temperature sensor 22
detects the temperature of air having passed through evaporator 13,
and a refrigerant leakage detection sensor 23 detects leakage of
refrigerant from refrigerating cycle 1 at this position.
Refrigerant leakage detection sensor 23 may be disposed at another
desired position, and further, another refrigerant leakage
detection sensor may be added at another appropriate position. Air
conditioning system 100 also may comprise respective air discharge
ports 24, 25, and 26 downstream of evaporator 13 within air duct
14, such as air discharge ports for a DEFROST mode, a VENT mode,
and a FOOT mode. Air discharge ports 24, 25, and 26 may be
selected, and their opening and closing may be controlled by
dampers 27, 28, and 29, respectively.
[0022] Air conditioning system 100 also may comprise a main
controller 30. The signals from the above-described evaporator exit
air temperature sensor 22 and refrigerant leakage detection sensor
23 are sent to main controller 30. Further, in this embodiment, a
signal indicating engine rotational speed 31, a signal indicating
vehicle running speed 32, a signal indicating detected pressure
from the above-described pressure sensor 11, a signal indicating
detected interior temperature from a vehicle interior temperature
sensor 33, a signal indicating detected outside temperature from an
outside air temperature sensor 34, a signal indicating the
intensity of sunshine integral, from a sunshine sensor 35, and a
signal from a collision sensor 36 provided as a vehicle collision
detection device capable of detecting or predicting a vehicle
collision may be sent to main controller 30. Further, from main
controller 30, a clutch signal 37 may be sent to clutch controller
4, a displacement control signal 38 may be sent to compressor 3,
and an electromagnetic valve control signal 39 may be sent to
electromagnetic solenoid 10, respectively.
[0023] FIG. 2 depicts an example of the structure of integral,
refrigerant recovery vessel and gas-liquid separator device 9. A
desiccant 40 and a filter 41 are disposed in an upper portion of
gas-liquid separator 7, and liquid refrigerant 43 is stored in a
space 42 below the filter 41. Refrigerant is introduced into this
upper portion through an inlet tube 51, and liquid refrigerant 43
is discharged from liquid refrigerant storing space 42 through an
outlet tube 52. Although this structure may not differ
significantly from a known, gas-liquid separator, in this
embodiment, refrigerant recovery vessel 8 is added to integral
device 9 below gas-liquid separator 7 (at a position below liquid
refrigerant storing space 42). An electromagnetic valve 45 with a
valve 44 operated by electromagnetic solenoid 10 is disposed
between liquid refrigerant storing space 42 and refrigerant
recovery vessel 8, and communication between liquid refrigerant
storing space 42 and refrigerant recovery vessel 8 is controlled by
the operation of valve 44 in response to an electromagnetic valve
control signal 39 sent from main controller 30 to electromagnetic
solenoid 10. In particular, when valve 44 is opened, liquid
refrigerant 43 in liquid refrigerant storing space 42 is drawn into
refrigerant recovery vessel 8, and when valve 44 is closed, liquid
refrigerant 43 is no longer drawn into refrigerant recovery vessel
8. Valve 44 is a normally closed-type valve (e.g., electromagnetic
valve) which is opened when electromagnetic solenoid 10 is
energized.
[0024] With respect to the method for recovering combustible
refrigerant in the air conditioning system thus constructed,
examples of two embodiments are explained as follows.
[0025] In a first embodiment, when a vehicle collision is detected
or predicted by collision sensor 36 provided as a vehicle collision
detection device, electromagnetic solenoid 10 is energized, and
combustible refrigerant in gas-liquid separator 7 is drawn into
refrigerant recovery vessel 8. Further, in this recovery, when the
pressure detected by pressure sensor 11 equals or exceeds a
predetermined value, or, when a predetermined time period expires,
electromagnetic solenoid 10 is de-energized, thereby stopping the
refrigerant recovery.
[0026] In a second embodiment, when a refrigerant leakage is
detected by refrigerant leakage detection sensor 23 provided in air
conditioning system 100, electromagnetic solenoid 10 is energized,
and combustible refrigerant in gas-liquid separator 7 is drawn into
refrigerant recovery vessel 8. Further, in this recovery, when the
pressure detected by pressure sensor 11 equals or exceeds a
predetermined value, or, when a predetermined time period expires,
electromagnetic solenoid 10 is de-energized, thereby stopping the
refrigerant recovery.
[0027] When the above-described embodiments of recovery operations
are carried out, the drive of compressor 3 is preferably
stopped.
[0028] Thus, when there is a risk that combustible refrigerant
leaks outside of the refrigerating cycle, or when leakage actually
occurs, in order to prevent leakage of a significant amount of
refrigerant, the combustible refrigerant is recovered quickly into
refrigerant recovery vessel 8. Consequently, the amount of
refrigerant leakage may be reduced, minimized, or eliminated, and
the ability of the system to reduce the risk of fire or explosion
may be significantly enhanced. In this structure, as described
above, because integral, refrigerant recovery vessel and gas-liquid
separator device 9 may be disposed at a position similar to that at
which known, gas-liquid separators have been disposed, the
refrigerant recovery may be carried out readily and efficiently
without requiring significant changes to the system
configuration.
[0029] Although refrigerant recovery vessel 8 is integral with
gas-liquid separator 7 in the above-described embodiment, these
components may be formed separately. Further, a structure may be
employed wherein the communication between gas-liquid separator 7
and refrigerant recovery vessel 8 is not enclosed within integral,
refrigerant recovery vessel and gas-liquid separator device 9. An
external communication path may be provided, and a valve, such as
an electromagnetic valve, may be provided in the external
communication path.
[0030] The present invention may be applied to any vehicle air
conditioning system comprising a vapor compression-type,
refrigerating cycle and using combustible refrigerant, thereby
realizing an air conditioning system for vehicles with a
significantly reduced risk of fire or explosion, even if
combustible refrigerant is used.
[0031] While the invention has been described in connection with
preferred embodiments, it will be understood by those skilled in
the art that variations and modifications of the preferred
embodiments described above may be made without departing from the
scope of the invention. Other embodiments will be apparent to those
skilled in the art from a consideration of the specification or
from a practice of the invention disclosed herein. It is intended
that the specification and the described examples are considered
exemplary only, with the true scope of the invention indicated by
the following claims.
* * * * *