U.S. patent number 3,828,569 [Application Number 05/378,228] was granted by the patent office on 1974-08-13 for automotive air conditioning system.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to Thomas W. Weisgerber.
United States Patent |
3,828,569 |
Weisgerber |
August 13, 1974 |
AUTOMOTIVE AIR CONDITIONING SYSTEM
Abstract
An air conditioning system including a condenser, an expansion
means, an evaporator and a vane-type refrigerant compressor. The
housing of the compressor encloses an oblong chamber in which a
rotor member is turned. Radially extending vanes are mounted within
slots in the rotor which extend across the radial space between
rotor and housing. The vanes are in fluid contact with undervane
control chambers. Fluid force in the control chambers is
selectively applied to the vanes to press them across the radial
space into engagement with the opposite wall of the compressor,
whereby compression chambers are formed between adjacent vanes.
Inventors: |
Weisgerber; Thomas W. (Saginaw,
MI) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
23492272 |
Appl.
No.: |
05/378,228 |
Filed: |
July 11, 1973 |
Current U.S.
Class: |
62/227; 62/243;
418/23; 418/268; 62/229; 62/498; 418/82 |
Current CPC
Class: |
F04C
28/06 (20130101); F25B 1/00 (20130101); F01C
21/0872 (20130101); F25B 2600/02 (20130101); F25B
1/04 (20130101) |
Current International
Class: |
F25B
1/00 (20060101); F01C 21/00 (20060101); F01C
21/08 (20060101); F25b 001/00 () |
Field of
Search: |
;62/227,229,243,244,323,498 ;418/82 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Perlin; Meyer
Attorney, Agent or Firm: McLean, Jr.; K. H.
Claims
What is claimed is as follows:
1. In an automobile air conditioning system for a compartment
including a condenser, an expansion means and an evaporator, a
simple temperature control system comprising:
a refrigerant compressor having a rotor supported for continuous
rotation by an automobile engine in a chamber defined by a
compressor housing;
said chamber and said rotor being configured with rises to produce
alternating larger and smaller radial distances therebetween;
radially projecting vanes supported in generally axial slots of
said rotor for rotation therewith forming compression chambers
between adjacent vane members;
inlet and outlet means in said housing positioned downstream and
upstream respectively from said rises for introducing and
discharging refrigerant from said compression chambers;
said rotor having undervane passage means adjacent the inner edge
of each vane to permit a radial force to be applied to the vanes by
fluid pressure therein;
pressure control passage means formed in the end of said compressor
housing and angularly located with respect to the beginning and
termination of said rises to make fluid connection with said
undervane passage means when said vanes are rotated into alignment
therewith and pass the beginning and termination of each of said
rises;
auxiliary fluid pressurization means connected to said rotor for
rotation therewith and being fluidly connected to said pressure
control passage means to pressurize said undervane passage means
and press said vanes radially outward against said housing thereby
compressing fluid in said compression chambers formed thereby;
thermostatically controlled means for controlling the
pressurization of said undervane passages in response to changes in
the temperature of a compartment to be cooled.
2. In an automobile air conditioning system for a compartment
including a condenser, an expansion means and an evaporator, a
simple temperature control system comprising:
a refrigerant compressor having a rotor supported for continuous
rotation by an automobile engine in a chamber defined by a
compressor housing;
said chamber and said rotor being configured with rises to produce
alternating larger and smaller radial distances therebetween;
radially projecting vanes supported in generally axial slots of
said rotor for rotation therewith forming compression chambers
between adjacent vane members;
inlet and outlet means in said housing positioned downstream and
upstream respectively from said rises for introducing and
discharging refrigerant from said compression chambers;
said rotor having undervane passage means adjacent the inner edge
of each vane to permit a radial force to be applied to the vanes by
fluid pressure therein;
pressure control passage means formed in the end of said compressor
housing and angularly located with respect to the beginning and
termination of said rises to make fluid connection with said
undervane passage means when said vanes are rotated into alignment
therewith and pass the beginning and termination of each of said
rises;
auxiliary fluid pressurization means connected to said rotor for
rotation therewith and being fluidly connected to said pressure
control passage means to pressurize said undervane passage means
and press said vanes radially outward against said housing thereby
compressing fluid in said compression chambers formed thereby;
means extending from the outlet of said fluid pressurization means
to said control passage means in said compressor housing for
transmitting pressure to said undervane passage means aligned
therewith;
selectively activated valve means in said pressure transmitting
means for controlling the pressurization of said control passage
means and undervane passage means;
thermostatically controlled means selectively actuating said valve
means to permit pressurization of said undervane passage means at
compartment temperatures above a desired temperature.
3. In an automobile air conditioning system for a compartment
including a condenser, an expansion means and an evaporator, a
simple temperature control system comprising:
a refrigerant compressor having a rotor supported for continuous
rotation by an automobile engine in a chamber defined by a
compressor housing;
said chamber and said rotor being configured with rises to produce
alternating larger and smaller radial distances therebetween;
radially projecting vanes supported in generally axial slots of
said rotor for rotation therewith forming compression chambers
between adjacent vane members;
inlet and outlet means in said housing positioned downstream and
upstream respectively from said rises for introducing and
discharging refrigerant from said compression chambers;
said rotor having undervane passage means adjacent the inner edge
of each vane to permit a radial force to be applied to the vanes by
fluid pressure therein;
pressure control passage means formed in the end of said compressor
housing and angularly located with respect to the beginning and
termination of said rises to make fluid connection with said
undervane passage means when said vanes are rotated into alignment
therewith and pass the beginning and termination of each of said
rises;
auxiliary fluid pressurization means connected to said rotor for
rotation therewith and being fluidly connected to said pressure
control passage means to pressurize said undervane passage means
and press said vanes radially outward against said housing thereby
compressing fluid in said compression chambers formed thereby;
first pressure transmitting means connected to said control passage
means located adjacent the termination of each rise for
pressurizing said control passage means and undervane passage means
aligned therewith;
second pressure transmitting means connected to said control
passage means located adjacent the beginning of each rise for
pressurizing said control passage means and undervane passage means
aligned therewith;
first valve means controlling the pressurization of said first
control passage means for permitting the selective pressurization
or depressurization thereof;
second valve means controlling the pressurization of both first and
second control passage means for permitting the selective
pressurization or depressurization thereof;
means including solenoid valve actuators associated with said first
and second valve means and a thermally responsive member in the
compartment for opening said valve means when the compartment
temperature is above a desired preselected temperature and for
closing said valve means when it is below said temperature thereby
controlling the compressing action of said compressor by
pressurizing or depressurizing said undervane passage means;
pressure relief means connected between said first and second valve
means thereby relieving the pressure in said undervane passage
means as they are aligned with said second control chamber means
whenever said valve means are closed.
Description
This invention relates to air conditioning systems having fluid
control means to activate and inactivate the refrigerant compressor
in response to desired temperature setting for a compartment to be
air conditioned.
Prior air conditioning systems for automobile use have utilized
electromagnetic clutch means between a drive pulley and the
refrigerant compressor for selectively operating the compressor in
response to air conditioning needs. The electromagnetic clutch is a
relatively costly item and is subject to failure due to wear and
tear caused by the continuous stopping and starting of the
compressor.
The subject air conditioning system utilizes a vane-type compressor
in which vanes are supported within axial slots in a rotor and
extend radially across the space between the rotor and a
surrounding housing of the compressor. At the base of the slots an
undervane pressure control passage extends to fluidly engage one
edge of the vane. When pressurized fluid is introduced into the
undervane passage, the resultant radial force on the vane causes it
to be extended across the radial space and contact the opposite
chamber wall. As the rotor turns in the housing, the vane is
pressed into engagement with the inner surface of the housing to
compress refrigerant trapped within compression chambers formed
between adjacent vanes.
Solenoid actuated valves are electrically connected to a thermostat
in the compartment to be air conditioned to control the
pressurization of undervane passages at the base of the vanes. When
the temperature in the compartment rises above a predetermined
value, the thermostat energizes the solenoid valves and causes them
to open thus introducing pressurized fluid to the undervane
passages to cause the vanes to extend radially across the space
between the rotor and the housing. This produces refrigerant
compression and resultant cooling. When the temperature in the
compartment falls below a predetermined desired value, the
thermostat deenergizes the solenoid coil and the valves are closed
to depressurize the undervane passage and permit the vanes to
retract into the slots of the rotor thus discontinuing compression
of refrigerant.
A convenient source of pressurized undervane fluid is the oil which
is normally mixed with refrigerant in an air conditioning system
for lubricating bearings and seals of the compressor. Most
refrigerant compressors include small gear-type oil pumps to
pressurize and circulate the oil and cause it to flow through the
bearings and against the seal surfaces. The addition of passages
from the outlet of the oil pump extending to the undervane passages
permits the vanes to be moved by oil pressure radially against the
opposite surface of the housing during operation of the
compressor.
Therefore, an object of the present invention is to provide an
auxiliary fluid pressurizing means in a vane-type compressor to
selectively apply fluid pressure to edge portions of the compressor
vanes to cause the vanes to move into contact with the opposite
portion of the housing to form compression chambers
therebetween.
A further object of the present invention is to provide a vane-type
compressor which has radially extending vanes mounted within axial
slots of a rotor with undervane fluid control passages formed along
the base of the slots which permit the introduction of pressurized
fluid to force the vane to move radially through the space between
the rotor and the housing to form compression chambers
therebetween.
A still further object of the present invention is to provide
simple and economical automatic control of a refrigerant compressor
by utilizing pressurized hydraulic fluid which is selectively
transmitted to the compressor by thermostatically controlled
electric solenoid valves.
A particular advantage of the fluid pressure controlled system is
that it permits the oil pump of a refrigerant compressor to be run
continuously whenever the car engine is running, thus insuring a
supply of oil for the compressor's shaft seals and bearings at all
times. Particularly during prolonged shutdown, such as in
wintertime, it is desirable to supply the seal with oil to prevent
it from "drying out." When it "drys out" it may fail in the summer
after the initial start up.
Further objects and advantages of the present invention will be
more readily apparent from the following detailed description,
reference being had to the accompanying drawings in which a
preferred embodiment is shown.
In the single FIGURE of the drawings, a somewhat schematic view of
an air conditioning system with a desired vane-type air compressor
is illustrated .
A refrigerant compressor 10 is illustrated having a housing 12
which encloses an interior space 14. A rotor 16 is supported within
space 14 for rotation by means of a pulley and belt powered by the
automobile engine. Outlet port means 18 is connected by a
refrigerant conduit 20 to a condensor 22 which is normally
installed in front of the automobile radiator in the airstream
through the grille. The condensor 22 is connected by conduit 24 to
a receiver 26 whose housing encloses a chamber 28 in which liquid
refrigerant is separated from vaporous refrigerant. A conduit 30
extends downward into the interior 28 toward the bottom of the
receiver 26 to draw off only liquid refrigerant and transmit it to
expansion valve means 32.
Valve means 32 reduces the relatively high pressure refrigerant to
a lower pressure. Opening and closing of the valve means 32 is
controlled by pressure exerted against a diaphragm (not visible)
within the upper portion 34 of the valve means. A space on one side
of the diaphragm is connected by a capillary line 36 to a
temperature sensor 38 to develop control pressure proportional to
refrigerant temperature at the location of sensor 38. The resultant
pressure is transmitted through the capillary line 36 to the
expansion valve means 32.
A conduit 40 transmits the low liquid refrigerant from valve 32 to
evaporator means 42 which is located so that air passing into a
passenger compartment flows over its exterior cooling surfaces. The
refrigerant within the evaporator 42 is vaporized therein by the
extraction of heat from the air flowing over the exaporator. The
refrigerant then flows through a conduit 44 and into a throttling
valve 46.
The throttling valve is a pressure operated device which maintains
evaporator pressure above a level which corresponds to a 32.degree.
F temperature of the refrigerant. By restricting or throttling the
outlet of the evaporator to maintain refrigerant within the
evaporator, the refrigerant pressure is maintained above the
aforementioned freezing level. This prevents moisture which
condenses on the outer surfaces of the evaporator from freezing
thereon and eventually blocking air flow through the evaporator.
Refrigerant then flows from the throttling valve 46 through a
suction line 48 to inlet port means 50 of the compressor.
The compressor 10 has radially outwardly extending vanes 52 which
are supported within axially directed slots 54 within rotor 16.
When the refrigerant compressor is in an active mode of operation,
the vanes 52 extend across the radial distance or space between the
rotor 16 and the housing 12 and contact the inner peripheral wall
56 of housing 12. The inner peripheral wall 56 of housing 12
defines an oblong space in which the rotor 16 is mounted for
rotation. Portions 57 of wall 56 opposite one another are spaced
from rotor 16 a greater distance than portions 59 which are between
portions 57. The radial distance between rotor 16 and wall 56
varies as the rotor turns clockwise to produce variable volume
compression chambers 58 between adjacent vanes 52.
Refrigerant is drawn through inlet port means 50 into expanding
compression chambers 58a and is discharged through outlet port
means 18 from a contracting compression chamber 58b. It should be
noted that the compressor illustrated is a two rise compressor with
two inlets and two outlets which are adapted to be connected to
lines 48 and 20, respectively. A single rise or three, four rise
compressor could also be used.
The compressor 10 includes a small gear-type oil pump 60 shown in
the drawing detached from the compressor 10. Actually, the oil pump
60 is located adjacent one end of the rotor 16 within housing 12
but is shown in a detached view only for clarity. The oil pump
includes a driven gear member 62 and an idler gear member 64. The
gear member 62 is operably connected to the rotor 16 to turn with
it in the direction shown by arrow 66.
The oil pump 60 draws oil from a sump region 68 of compressor 10
(shown symbolically) through a passage 70 and discharges the oil
into passage 72. The pressurized oil then flows through passage
means 74 to bearings and seals of the compressor shown
schematically by box 76 of the compressor 10. Here again, the
bearings and seals are a portion of compressor 10, but are shown
schematically and detached from the compressor only for clarity.
After engaging the bearings and seals, the oil passes through
passage means 78 back to inlet passage 70 or to sump 68. Thus,
whenever the rotor 16 of the compressor 10 is rotated, as is the
case as long as the automobile engine is operative, oil is fed by
oil pump 60 to the bearings and seals. There will be no prolonged
period of time for the seals to "dry-out" as long as the automobile
engine is operated periodically.
As described so far, the system would desirably cool a passenger
compartment of an automobile. However, there will be times when the
temperature of ambient or the compartment will fall below a
comfortable temperature and air conditioning will, therefore, no
longer be desirable. In fact, when ambient temperature falls below
about 45.degree. there most likely will be insufficient heat
transfer from the air in the compartment to warm the evaporator 42
sufficiently to prevent frost from forming on its exterior
surfaces. Further, the system will be uneconomical due to excessive
operation of the compressor when not needed.
The present air conditioning system utilizes a compressor which is
simply and easily deactivated to selectively prevent the
pressurization of refrigerant therein even as the rotor 16
continues to be turned. Fluid filled control chambers 79 and 80 in
the end of compressor housing 12 are aligned with undervane control
passage means 81 in the rotor as it turns. Control passages 79, 80
are positioned in the end of housing 12 to progressively be fluidly
connected with the undervane passage 81 at the start of the pumping
stroke and the end of a pumping stroke, respectively. Passages 81
are selectively supplied with pressurized oil from passages 79, 80
and pump 60 to cause the rotors 52 to be forced radially outward
against the surface 56 of housing 12 when compressing action is
desired. Control chambers 79, 80 are connected by fluid passage
means 82, 83 to the outlet 72 of oil pump 60.
When air conditioning of the compartment is desired, pressurized
oil from pump 60 is transmitted through the passage means 82, 83 to
the control chambers 79, 80 which causes the vanes 52 to be moved
radially in slots 54 against the surface 56 of casing 12. This
separates and seals adjacent compression chambers 58 from one
another and results in pressurization of refrigerant as the vanes
move from inlet 50 to outlet 18.
When a compartment to be air conditioned is cooler than a desired
temperature, thermostatic switch means 84 located in the
compartment will cause valves 86, 87 to close. The valves 86, 87
are positioned in passage means 82, 83 to control oil
pressurization of control chambers 79, 80. Solenoid coils 88
actuate valves 86, 87 by energization through wires 91, 93 from
thermostat 84. When the valves 86, 87 close, the supply of
pressurized oil is blocked to control passages 79, 80 and trapped
fluid therein is discharged to relief line 90 to permit the vanes
52 to retract within slots 54 and away from surface 56. In this
position, refrigerant will not be compressed during rotation of the
rotor 16. When the valves 86, 87 are again opened, a small amount
of pressurized oil is necessary to again pressurize the chambers
79, 80, 81 and provide sufficient undervane pressure to cause the
vanes to extend radially against the surface 56.
Should any line blockage occur during a compressing mode of
operation when valves 86, 87 are open, a higher than normal
pressure may develop in the chambers 79, 80, 81. To relieve this
excess pressure, a relief passage 90 is provided which has a check
valve 92 therein which is normally closed. When pressure exceeds
the predetermined opening of the check valve 92, the oil may flow
past the check valve 92 and through a passage 94 back to the inlet
70 of the oil pump 60 thus relieving the pressure.
At the start of a compressing mode of operation, the valves 86, 87
are opened. Pressurized oil flows through valve 86 and passage
means 82 to cause pressurization of the undervane passages 81 which
are aligned with control chambers 79. As the vane rotates from a
position A at the start of a pumping cycle to a position B at the
end of a pumping cycle, the pressurization of the undervane chamber
81 keeps the vane against wall 57. As the vane rotates past
position B to its "retracted position," the oil displaced from the
undervane passage 81 is transmitted to passage 82 and control
chamber 79 through the open valve 86. Thus on startup once the
leakage is made-up, very little additional oil is needed for the
control and undervane passages.
When compressing action is no longer needed and valves 86 and 87
are closed, the retraction of vanes 52 in slots 54 displace the oil
from passages 81 and control chambers 80 to relief line 90 and past
valve 92. Pressurized oil is prevented from being transferred from
control chamber 80 to control chamber 79 by the closed valve 86.
Since no additional oil is supplied to chambers 79, the vanes 52
remain retracted and no compressing occurs.
Although the embodiment illustrated is a preferred embodiment,
other minor variations could be provided without falling outside
the scope of the following claims which define the invention.
* * * * *