U.S. patent application number 15/513469 was filed with the patent office on 2017-10-26 for ejector-type refrigeration cycle device.
The applicant listed for this patent is DENSO CORPORATION. Invention is credited to Yoshinori ARAKI, Makoto KUME, Youhei NAGANO, Haruyuki NISHIJIMA, Toshiyuki TASHIRO, Masahiro YAMADA, Yoshiyuki YOKOYAMA.
Application Number | 20170307259 15/513469 |
Document ID | / |
Family ID | 55760506 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170307259 |
Kind Code |
A1 |
ARAKI; Yoshinori ; et
al. |
October 26, 2017 |
EJECTOR-TYPE REFRIGERATION CYCLE DEVICE
Abstract
When intended to increase a refrigerant discharge capacity of a
compressor in an ejector refrigeration cycle device at start-up of
the compressor, the refrigerant discharge capacity is increased in
such a manner that an increase amount in the refrigerant discharge
capacity of the compressor per predetermined time period is lower
than a maximum capacity increase amount per predetermined time
period enabled by the compressor. Thus, even if a gas-liquid
two-phase refrigerant flows into a refrigerant inflow passage
forming a swirling-flow generating portion, the flow velocity of
the gas-liquid two-phase refrigerant is prevented from becoming
high, so that it can reduce friction noise that would be caused
when the gas-liquid two-phase refrigerant circulates through the
refrigerant inflow passage, further suppressing the generation of
noise from the ejector.
Inventors: |
ARAKI; Yoshinori;
(Kariya-city, JP) ; TASHIRO; Toshiyuki;
(Kariya-city, JP) ; YAMADA; Masahiro;
(Kariya-city, JP) ; KUME; Makoto; (Kariya-city,
JP) ; NISHIJIMA; Haruyuki; (Kariya-city, JP) ;
NAGANO; Youhei; (Kariya-city, JP) ; YOKOYAMA;
Yoshiyuki; (Kariya-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION |
Kariya-city, Aichi-pref. |
|
JP |
|
|
Family ID: |
55760506 |
Appl. No.: |
15/513469 |
Filed: |
August 18, 2015 |
PCT Filed: |
August 18, 2015 |
PCT NO: |
PCT/JP2015/004094 |
371 Date: |
March 22, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 2600/2515 20130101;
F25B 1/06 20130101; F25B 2341/0011 20130101; F25B 5/02 20130101;
F25B 6/04 20130101; F25B 2700/2106 20130101; F25B 41/00 20130101;
F25B 39/02 20130101; F25B 2700/2117 20130101; F25B 2700/2104
20130101; F25B 39/00 20130101; F25B 2341/0012 20130101; F25B
2341/001 20130101; F25B 2341/0014 20130101; F25B 41/04
20130101 |
International
Class: |
F25B 1/06 20060101
F25B001/06; F25B 5/02 20060101 F25B005/02; F25B 41/00 20060101
F25B041/00; F25B 39/02 20060101 F25B039/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2014 |
JP |
2014-217455 |
Claims
1. An ejector refrigeration cycle device, comprising: a compressor
that compresses and discharges a refrigerant; a radiator that
dissipates heat from the refrigerant discharged from the
compressor; a swirling-flow generating portion that generates a
swirling flow in the refrigerant flowing out of the radiator; an
ejector including a body portion, the body portion being provided
with a nozzle portion that decompresses the refrigerant flowing out
of the swirling-flow generating portion, a refrigerant suction port
that draws a refrigerant by a suction effect of the injection
refrigerant injected from the nozzle portion at a high velocity,
and a pressurizing portion that mixes the injection refrigerant
with the suction refrigerant drawn from the refrigerant suction
port to pressurize the mixed refrigerant; an evaporator that
evaporates the refrigerant, and allows the evaporated refrigerant
to flow out to the refrigerant suction port; and a
discharge-capacity control unit that controls a refrigerant
discharge capacity of the compressor, wherein the swirling-flow
generating portion is configured to have a part forming a swirl
space in a rotator shape, and a part forming a refrigerant inflow
passage through which the refrigerant flows along a peripheral
sidewall of the swirl space and flows into the swirl space, and the
discharge-capacity control unit increases the refrigerant discharge
capacity of the compressor in such a manner that an increase amount
in the refrigerant discharge capacity of the compressor per
predetermined time period is lower than a reference capacity
increase amount at start-up of the compressor.
2. The ejector refrigeration cycle device according to claim 1,
wherein the reference capacity increase amount is a maximum
capacity increase amount per predetermined time period, enabled by
the compressor.
3. An ejector refrigeration cycle device, comprising: a compressor
that compresses and discharges a refrigerant; a radiator that
dissipates heat from the refrigerant discharged from the
compressor; a swirling-flow generating portion that generates a
swirling flow in the refrigerant flowing out of the radiator; an
ejector including a body portion, the body portion being provided
with a nozzle portion that decompresses the refrigerant flowing out
of the swirling-flow generating portion, a refrigerant suction port
that draws a refrigerant by a suction effect of the injection
refrigerant injected from the nozzle portion at a high velocity,
and a pressurizing portion that mixes the injection refrigerant
with the suction refrigerant drawn from the refrigerant suction
port to pressurize the mixed refrigerant; an evaporator that
evaporates the refrigerant, and allows the evaporated refrigerant
to flow out to the refrigerant suction port; and an inflow rate
adjustment portion that adjusts an inflow rate of the refrigerant
flowing into the swirling-flow generating portion, wherein the
swirling-flow generating portion is configured to have a part
forming a swirl space in a rotator shape, and a part forming a
refrigerant inflow passage through which the refrigerant flows
along a peripheral sidewall of the swirl space and flows into the
swirl space, and the inflow rate adjustment portion increases the
refrigerant inflow rate in such a manner that an increase amount in
the refrigerant inflow rate per predetermined time period is lower
than a reference flow-rate increase amount at start-up of the
compressor.
4. The ejector refrigeration cycle device according to claim 3,
wherein the reference flow-rate increase amount is a maximum
flow-rate increase amount per predetermined time period, enabled by
the inflow rate adjustment portion.
5. The ejector refrigeration cycle device according to claim 3,
wherein the inflow rate adjustment portion is disposed in a
refrigerant flow path that leads from a refrigerant outlet of the
radiator to an inlet of the swirling-flow generating portion.
6. The ejector refrigeration cycle device according to claim 3,
further comprising a gas-liquid separation portion that separates
the refrigerant flowing out of the pressurizing portion into gas
and liquid phase refrigerants, wherein the inflow rate adjustment
portion is disposed in a refrigerant flow path that leads from a
gas-phase refrigerant outflow port of the gas-liquid separation
portion to a suction port of the compressor.
7. The ejector refrigeration cycle device according to claim 3,
wherein the inflow rate adjustment portion is configured of an
electric flow-rate adjustment valve.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] The application is based on a Japanese Patent Application
No. 2014-217455 filed on Oct. 24, 2014, the contents of which are
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present disclosure relates to an ejector refrigeration
cycle device that includes an ejector serving as a refrigerant
decompression portion.
BACKGROUND ART
[0003] Conventionally, an ejector refrigeration cycle device is
known to be a vapor compression refrigeration cycle device
including an ejector as a refrigerant decompression portion.
[0004] This kind of ejector refrigeration cycle device can increase
the pressure of a suction refrigerant by the pressurizing effect of
the ejector, as compared with a normal refrigeration cycle device
in which a refrigerant evaporator pressure in an evaporator becomes
substantially equal to a pressure of a suction refrigerant drawn
into a compressor. Thus, the ejector refrigeration cycle device can
reduce the power consumption in the compressor to thereby improve a
coefficient of performance (COP) of the cycle.
[0005] Furthermore, Patent Document 1 discloses an ejector
refrigeration cycle device that includes an ejector with a swirl
space for causing swirling flow in a supercooled liquid-phase
refrigerant flowing into a nozzle portion (nozzle passage).
[0006] In the ejector disclosed in Patent Document 1, a supercooled
liquid-phase refrigerant is swirled in the swirl space to thereby
decompress and boil the refrigerant on a swirl center side, so that
the refrigerant is converted into a two-phase separated state that
contains a larger amount of the gas-phase refrigerant on the center
side rather than in an outer region of the swirl space. By allowing
such a refrigerant in the two-phase separated state to flow into
the nozzle passage, boiling of the refrigerant is promoted in the
nozzle passage, thereby improving the energy conversion efficiency
when converting the pressure energy of the refrigerant into kinetic
energy in the nozzle passage.
RELATED ART DOCUMENT
Patent Document
[0007] Patent Document 1: Japanese Unexamined Patent Application
Publication No. 2013-177879
SUMMARY OF INVENTION
[0008] Meanwhile, based on the studies by the inventors, it is
found that the ejector refrigeration cycle device described in
Patent Document 1 might cause noise from the ejector at start-up of
the compressor. It should be noted that the term "start-up of the
compressor" as used herein includes a period of time immediately
after start-up of the compressor, at least from when the compressor
does not exhibit its refrigerant discharge capacity till when the
compressor exhibits a desired target refrigerant discharge
capacity.
[0009] Thus, the inventors have examined the causes of noise and
found that such noise is caused by the fact that, for example, when
activating the ejector refrigeration cycle device at a high outside
air temperature, the gas-liquid two-phase refrigerant if not cooled
sufficiently might flow out of the radiator at start-up of the
compressor and enter the ejector.
[0010] This is because the ejector disclosed in Patent Document 1
sets a passage cross-sectional area of a refrigerant inflow passage
for guiding the refrigerant from the outside of the ejector into
the swirl space to a relatively small value to appropriately swirl
the supercooled liquid-phase refrigerant flowing into the swirl
space.
[0011] Thus, if a gas-liquid two-phase refrigerant flows into the
refrigerant inflow passage, the gas-liquid two-phase refrigerant
circulating through the refrigerant inflow passage flows at a high
velocity, compared with when a supercooled liquid-phase refrigerant
with a higher density flows thereinto, and causes friction noise
when passing through the refrigerant inflow passage. Further, if
the friction noise resonates with the gas-phase refrigerant
eccentrically located in a columnar shape on the center side of the
swirl space, a so-called air column resonance might make
significant noise.
[0012] The present disclosure has been made in view of the
foregoing points, and it is an object of the present disclosure to
provide an ejector refrigeration cycle device that includes an
ejector having a swirling-flow generating portion to reduce noise
generated from an ejector at start-up of the compressor.
[0013] An ejector refrigeration cycle device according to a first
aspect of the present disclosure includes: a compressor that
compresses and discharges a refrigerant; a radiator that dissipates
heat from the refrigerant discharged from the compressor; a
swirling-flow generating portion that generates a swirling flow in
the refrigerant flowing out of the radiator; an ejector including a
body portion, the body portion being provided with a nozzle portion
that decompresses the refrigerant flowing out of the swirling-flow
generating portion, a refrigerant suction port that draws a
refrigerant by a suction effect of the injection refrigerant
injected from the nozzle portion at a high velocity, and a
pressurizing portion that mixes the injection refrigerant with the
suction refrigerant drawn from the refrigerant suction port to
pressurize the mixed refrigerant; an evaporator that evaporates the
refrigerant, and allows the evaporated refrigerant to flow out to
the refrigerant suction port; and a discharge-capacity control unit
that controls a refrigerant discharge capacity of the
compressor.
[0014] The swirling-flow generating portion is configured to have a
part forming a swirl space in a rotator shape, and a part forming a
refrigerant inflow passage through which the refrigerant flows
along a peripheral sidewall of the swirl space and flows into the
swirl space. Furthermore, the discharge-capacity control unit
increases the refrigerant discharge capacity of the compressor in
such a manner that an increase amount in the refrigerant discharge
capacity of the compressor per predetermined time period is lower
than a reference capacity increase amount at start-up of the
compressor.
[0015] Thus, the discharge-capacity control unit increases the
refrigerant discharge capacity in such a manner that an increase
amount in the refrigerant discharge capacity of the compressor per
predetermined time period is lower than a predetermined reference
capacity increase amount at start-up of the compressor. Therefore,
even if the gas-liquid two-phase refrigerant flows into the
refrigerant inflow passage, the flow velocity of the gas-liquid
two-phase refrigerant is prevented from becoming high, and thereby
it can reduce the friction noise that would be caused when the
gas-liquid two-phase refrigerant circulates through the refrigerant
inflow passage.
[0016] As a result, the ejector refrigeration cycle device
including the ejector with the swirling-flow generating portion can
suppress the generation of noise from the ejector at start-up of
the compressor. For example, the reference capacity increase amount
may adopt the maximum capacity increase amount per predetermined
time period enabled by the compressor, that is, the maximum
capacity increase amount per predetermined time period that is
determined by a capacity inherent to the compressor.
[0017] According to a second aspect of the present disclosure, an
ejector refrigeration cycle device includes: a compressor that
compresses and discharges a refrigerant; a radiator that dissipates
heat from the refrigerant discharged from the compressor; a
swirling-flow generating portion that generates a swirling flow in
the refrigerant flowing out of the radiator; an ejector including a
body portion, the body portion being provided with a nozzle portion
that decompresses the refrigerant flowing out of the swirling-flow
generating portion, a refrigerant suction port that draws a
refrigerant by a suction effect of the injection refrigerant
injected from the nozzle portion at a high velocity, and a
pressurizing portion that mixes the injection refrigerant with the
suction refrigerant drawn from the refrigerant suction port to
pressurize the mixed refrigerant; an evaporator that evaporates the
refrigerant, and allows the evaporated refrigerant to flow out to
the refrigerant suction port; and an inflow rate adjustment portion
that adjusts an inflow rate of the refrigerant flowing into the
swirling-flow generating portion
[0018] The swirling-flow generating portion is configured to have a
part forming a swirl space in a rotator shape, and a part forming a
refrigerant inflow passage through which the refrigerant flows
along a peripheral sidewall of the swirl space and flows into the
swirl space. Furthermore, the inflow rate adjustment portion
increases the refrigerant inflow rate in such a manner that an
increase amount in the refrigerant inflow rate per predetermined
time period is lower than a reference flow-rate increase amount at
start-up of the compressor.
[0019] Thus, the inflow rate adjustment portion is adapted to
increase the refrigerant inflow rate in such a manner that an
increase amount in the refrigerant inflow rate per predetermined
time period is lower than the predetermined reference flow-rate
increase amount at start-up of the compressor. Therefore, even if
the gas-liquid two-phase refrigerant flows into the refrigerant
inflow passage, the flow velocity of the gas-liquid two-phase
refrigerant is prevented from becoming high, and thereby it can
reduce the friction noise that would be caused when the gas-liquid
two-phase refrigerant circulates through the refrigerant inflow
passage.
[0020] As a result, the ejector refrigeration cycle device
including the ejector with the swirling-flow generating portion can
suppress the generation of noise from the ejector at start-up of
the compressor. For example, the reference flow-rate increase
amount may adopt the maximum flow-rate increase amount per
predetermined time period enabled by the inflow rate adjustment
portion.
[0021] It should be noted that the term "start-up of the
compressor" as used in the present disclosure includes a period of
time immediately after start-up of the compressor, at least from
when the compressor does not exhibit its refrigerant discharge
capacity till when the compressor exhibits a desired target
refrigerant discharge capacity. The number of refrigerant inflow
passages is not limited to one, but may be plural.
BRIEF DESCRIPTION OF DRAWINGS
[0022] FIG. 1 is an entire schematic configuration diagram of a
vehicle air conditioner to which an ejector refrigeration cycle
device according to a first embodiment is applied.
[0023] FIG. 2 is a block diagram showing an electric control unit
of the vehicle air conditioner in the first embodiment.
[0024] FIG. 3 is a flowchart showing control processing for the
vehicle air conditioner in the first embodiment.
[0025] FIG. 4 is a flowchart showing part of the control processing
for the vehicle air conditioner in the first embodiment.
[0026] FIG. 5 is an entire schematic configuration diagram of a
vehicle air conditioner to which an ejector refrigeration cycle
device according to a second embodiment is applied.
[0027] FIG. 6 is a block diagram showing an electric control unit
of the vehicle air conditioner in the second embodiment.
[0028] FIG. 7 is a flowchart showing control processing for the
vehicle air conditioner in the second embodiment.
[0029] FIG. 8 is a control characteristic diagram of a flow-rate
adjustment valve in the second embodiment.
[0030] FIG. 9 is a schematic entire configuration diagram of a
vehicle air conditioner to which an ejector refrigeration cycle
device according to a third embodiment is applied.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0031] A first embodiment of the present disclosure will be
described below with reference to FIGS. 1 to 4. As shown in the
entire configuration diagram of FIG. 1, an ejector refrigeration
cycle device 10 in this embodiment is applied to a vehicle air
conditioner 1 and serves to cool ventilation air to be blown into a
vehicle interior as a space to be air-conditioned (interior space).
Thus, a fluid to be cooled by the ejector refrigeration cycle
device 10 is the ventilation air.
[0032] The ejector refrigeration cycle device 10 forms a
subcritical refrigeration cycle in which a high-pressure side
refrigerant pressure does not exceed the critical pressure of the
refrigerant, using a hydrofluorocarbon (HFC)-based refrigerant
(e.g., R134a) as the refrigerant. Obviously, a hydrofluoroolefin
(HFO)-based refrigerant (e.g., R1234yf) or the like may also be
adopted as the refrigerant. Further, refrigerating machine oil for
lubricating a compressor 11 is mixed into the refrigerant, and part
of the refrigerating machine oil circulates through the cycle
together with the refrigerant.
[0033] Among components of the ejector refrigeration device 10, the
compressor 11 draws and pressurizes the refrigerant into a
high-pressure refrigerant and then discharges the pressurized
refrigerant. The compressor 11 is installed in an engine room
together with an internal combustion engine (engine) (not shown)
for outputting a traveling driving force. The compressor 11 is
driven by a rotational driving force output from the engine via a
pulley, a belt, etc.
[0034] More specifically, in this embodiment, the compressor 11
adopts a variable displacement compressor that can be configured to
adjust a refrigerant discharge capacity by changing its discharge
displacement. The discharge displacement (refrigerant discharge
capacity) of the compressor 11 is controlled by a control current
output from a controller 60, to be described later, to a discharge
displacement control valve of the compressor 11.
[0035] Here, the term "engine room" as used in this embodiment
means an exterior space that accommodates the engine and is
enclosed by a vehicle body, a firewall 50 to be described later,
and the like. The engine room is also called an engine compartment.
A discharge port of the compressor 11 is connected to a refrigerant
inflow port of a condensing portion 12a of a radiator 12.
[0036] The radiator 12 is a heat-dissipation heat exchanger that
cools the refrigerant by exchanging heat between a high-pressure
refrigerant discharged from the compressor 11 and a vehicle
exterior air (outside air) blown by a cooling fan 12d, thereby
dissipating heat from the high-pressure refrigerant. The radiator
12 is installed at the front side of the engine room in the
vehicle.
[0037] More specifically, the radiator 12 in this embodiment is
configured as a so-called subcool condenser that includes the
condensing portion 12a, a receiver 12b, and a supercooling portion
12c. The condensing portion 12a condenses the refrigerant by
exchanging heat between the high-pressure gas-phase refrigerant
discharged from the compressor 11 and the outside air blown from
the cooling fan 12d, thereby dissipating heat from the
high-pressure gas-phase refrigerant. The receiver 12b separates the
refrigerant flowing out of the condensing portion 12a into gas and
liquid phase refrigerants to store therein an excessive
liquid-phase refrigerant. The supercooling portion 12c supercools
the liquid-phase refrigerant by exchanging heat between the
liquid-phase refrigerant flowing out of the receiver 12b and the
outside air blown by the cooling fan 12d.
[0038] The cooling fan 12d is an electric blower that has the
number of revolutions (blown air volume) controlled by a control
voltage output from the controller 60. A refrigerant outflow port
of the supercooling portion 12c in the radiator 12 is connected to
a refrigerant inflow port 31a of an ejector module 13.
[0039] The ejector module 13 functions as a refrigerant
decompression portion that decompresses the high-pressure
liquid-phase refrigerant in the supercooled state flowing out of
the radiator 12, and also as a refrigerant circulation portion
(refrigerant transport portion) that draws (transports) the
refrigerant flowing out of an evaporator 14, to be described later,
by a suction effect of the refrigerant flow injected at a high
velocity, thereby circulating the refrigerant.
[0040] Furthermore, the ejector module 13 in this embodiment also
functions as a gas-liquid separator for separating the decompressed
refrigerant into gas and liquid phase refrigerants.
[0041] That is, the ejector module 13 in this embodiment is
configured as a "gas-liquid separator integrated ejector" or a
"gas-liquid separating function-equipped ejector". In this
embodiment, to clarify a difference from an ejector not having a
gas-liquid separator (gas-liquid separation space), an integrated
(modularized) configuration of the ejector and gas-liquid separator
will be hereinafter referred as the "ejector module".
[0042] The ejector module 13 is installed in the engine room,
together with the compressor 11 and the radiator 12. Note that the
respective up and down arrows in FIG. 1 indicate the respective
upward and downward directions with the ejector module 13 mounted
on the vehicle. Respective upward and downward directions in which
other components are mounted on the vehicle are not limited to the
above-mentioned up and down directions. FIG. 1 illustrates a
cross-sectional view of the ejector module 13 taken along the axial
direction thereof.
[0043] More specifically, as shown in FIG. 1, the ejector module 13
in this embodiment includes a body portion 30 formed by a
combination of a plurality of components. The body portion 30 is
formed of a columnar or prismatic metal member. The body portion 30
includes a plurality of refrigerant inflow ports, a plurality of
internal spaces, and the like.
[0044] Specifically, the refrigerant inflow/outflow ports formed in
the body portion 30 include the refrigerant inflow port 31a, a
refrigerant suction port 31b, a liquid-phase refrigerant outflow
port 31c, and a gas-phase refrigerant outflow port 31d. The
refrigerant inflow port 31a allows the refrigerant exiting the
radiator 12 to flow thereinto. A refrigerant suction port 31b draws
the refrigerant flowing out of the evaporator 14. The liquid-phase
refrigerant outflow port 31c allows the liquid-phase refrigerant
separated by a gas-liquid separation space 30f formed in the body
portion 30 to flow out to the refrigerant inlet side of the
evaporator 14. The gas-phase refrigerant outflow port 31d allows
the gas-phase refrigerant separated in the gas-liquid separation
space 30f to flow out to the suction side of the compressor 11.
[0045] The internal spaces formed in the body portion 30 include a
swirl space 30a, a decompression space 30b, a pressurizing space
30e, and the gas-liquid separation space 30f. The swirl space 30a
serves to swirl the refrigerant flowing thereinto from the
refrigerant inflow port 31a. The decompression space 30b serves to
decompress the refrigerant flowing out of the swirl space 30a. The
pressurizing space 30e serves to allow the refrigerant exiting the
decompression space 30b to flow thereinto. The gas-liquid
separation space 30f serves to separate the refrigerant flowing out
of the pressurizing space 30e into gas and liquid phases.
[0046] Each of the swirl space 30a and the gas-liquid separation
space 30f is formed to have a substantially columnar rotator shape.
Each of the decompression space 30b and the pressurizing space 30e
is formed as a substantially conical trapezoidal rotator shape that
gradually enlarges its diameter from the swirl space 30a side
toward the gas-liquid separation space 30f side. All the central
axes of these spaces are arranged coaxially. Note that the rotator
shape is a tridimensional shape formed by rotating a plane figure
about one straight line (central axis) located on the same
plane.
[0047] A suction passage 13b is formed in the body portion 30 so as
to guide the refrigerant drawn from the refrigerant suction port
31b toward the downstream side of the refrigerant flow in the
decompression space 30b and the upstream side of the refrigerant
flow in the pressurizing space 30e.
[0048] A refrigerant inflow passage 31e that connects the
refrigerant inflow port 31a to the swirl space 30a extends in the
tangential direction of an inner wall surface of the swirl space
30a as viewed from the central axis direction of the swirl space
30a. Thus, the refrigerant flowing from the refrigerant inflow
passage 31e into the swirl space 30a flows along the peripheral
sidewall of the swirl space 30a and then swirls around the central
axis of the swirl space 30a.
[0049] A centrifugal force acts on the refrigerant swirling within
the swirl space 30a, whereby the refrigerant pressure on the
central axis side of the swirl space 30 becomes lower than the
refrigerant pressure on the peripheral side thereof. Thus, in this
embodiment, during the normal operation of the ejector
refrigeration cycle device 10, the refrigerant pressure on the
central axis side in the swirl space 30a is reduced to a pressure
at which the refrigerant becomes a saturated liquid-phase
refrigerant, or a pressure at which the refrigerant is decompressed
and boiled (causing cavitation).
[0050] The adjustment of the refrigerant pressure on the central
axis side in the swirl space 30a in this way can be achieved by
adjusting the swirl flow velocity of the refrigerant swirling in
the swirl space 30a. Furthermore, the adjustment of the swirl flow
velocity can be performed, for example, by adjusting the ratio of
the passage cross-sectional area of the refrigerant inflow passage
31e to the cross-sectional area of the swirl space 30a in a
direction perpendicular to the axis direction.
[0051] Thus, in this embodiment, the passage cross-sectional area
of the refrigerant inflow passage 31e is formed to be smaller than
the cross-sectional area of the swirl space 30a in the direction
perpendicular to the axis direction and thereby is set to a
relatively small value. Note that the swirl flow velocity in this
embodiment means a flow velocity in the swirl direction of the
refrigerant located in the vicinity of the most peripheral part of
the swirl space 30a.
[0052] A passage formation member 35 is formed within the
decompression space 30b and the pressurizing space 30e. The passage
formation member 35 is formed in a substantially conical shape that
expands as toward the outer peripheral side as the passage
formation member 35 is spaced apart from the decompression space
30b. The central axis of the passage formation member 35 is
arranged coaxially with the central axis of the decompression space
30b and the like.
[0053] A refrigerant passage having an annular cross-sectional
shape in the direction perpendicular to the axial direction (a
doughnut shape obtained by removing a small-diameter circle from a
circle arranged coaxially therewith) is formed between the inner
peripheral surface of a part forming the decompression space 30b
and pressurizing space 30e of the body portion 30 and a conical
side surface of the passage formation member 35.
[0054] In such a refrigerant passage, a refrigerant passage part
between a part forming the decompression space 30b of the body
portion 30 and the tip side part of the conical side surface of the
passage formation member 35 is formed to have its passage
cross-sectional area throttled as toward the downstream side of the
refrigerant flow. The refrigerant passage part with this shape
configures a nozzle passage 13a serving as a nozzle portion that
isentropically decompresses and injects the refrigerant.
[0055] More specifically, the nozzle passage 13a in this embodiment
is formed to gradually decrease its passage cross-sectional area
from the inlet side of the nozzle passage 13a toward the minimum
passage area portion thereof, and to gradually enlarge its passage
cross-sectional area from the minimum passage area portion toward
the outlet side of the nozzle passage 13a. That is, the nozzle
passage 13a in this embodiment changes its refrigerant passage
cross-sectional area, like a so-called Laval nozzle.
[0056] Here, the above-mentioned swirl space 30a is disposed on the
upstream side of the refrigerant flow on the upper side of the
nozzle passage 13a. Thus, in the swirl space 30a of this
embodiment, the supercooled liquid-phase refrigerant flowing into
the nozzle passage 13a is allowed to swirl around the axis of the
nozzle passage 13a. Therefore, in this embodiment, a part of the
body portion 30 forming the swirl space 30a and a part forming the
refrigerant inflow passage 31e configure a swirling-flow generating
portion. In other words, in this embodiment, the ejector and the
swirling-flow generating portion are configured integrally.
[0057] On the other hand, another refrigerant passage part between
a part forming the pressurizing space 30e of the body portion 30
and a part on the downstream side of the conical side surface of
the passage formation member 35 is formed to gradually enlarge its
passage cross-sectional area toward the downstream side of the
refrigerant flow. The refrigerant passage part with this shape
configures a diffuser passage 13c that serves as a diffuser portion
(pressurizing portion) pressurizing a mixture of an injection
refrigerant injected from the nozzle passage 13a and a suction
refrigerant drawn from the refrigerant suction port 31b.
[0058] In the body portion 30, an element 37 is disposed as a
driving device for displacing the passage formation member 35 to
change the passage cross-sectional area of the minimum passage area
portion of the nozzle passage 13a.
[0059] More specifically, the element 37 includes a diaphragm that
is designed to be displaceable depending on the temperature and
pressure of the refrigerant circulating through the suction passage
13b (that is, the refrigerant flowing out of the evaporator 14).
The displacement of the diaphragm is transferred to the passage
formation member 35 via an operation stick 37a, thereby vertically
displacing the passage formation member 35.
[0060] The element 37 displaces the passage formation member 35 in
the direction (downward in the vertical direction) that enlarges
the passage cross-sectional area of the minimum passage area
portion with increasing temperature (degree of superheat) of the
refrigerant flowing out of the evaporator 14. On the other hand,
the element 37 displaces the passage formation member 35 in the
direction (upward in the vertical direction) that reduces the
passage cross-sectional area of the minimum passage area portion
with decreasing temperature (degree of superheat) of the
refrigerant flowing out of the evaporator 14.
[0061] In this embodiment, the element 37 displaces the passage
formation member 35 depending on the degree of superheat of the
refrigerant flowing out of the evaporator 14 in this way. Thus, the
passage cross-sectional area of the minimum passage area portion of
the nozzle passage 13a is adjusted such that the degree of
superheat of the refrigerant on the outlet side of the evaporator
14 approaches a predetermined reference degree of superheat.
[0062] The gas-liquid separation space 30f is disposed under the
passage formation member 35. The gas-liquid separation space 30f
configures a centrifugal gas-liquid separator that swirls the
refrigerant flowing out of the diffuser passage 13c around its
central axis to thereby separate it into gas and liquid phase
refrigerants by a centrifugal effect.
[0063] Further, in this embodiment, the internal capacity of the
gas-liquid separation space 30f is set to a level that can store
only a very small amount of excessive refrigerant or cannot
substantially retain excessive refrigerant even though the flow
rate of refrigerant circulating through the cycle is varied due to
fluctuations in the load on the cycle. In this way, this embodiment
enables the downsizing of the entire ejector module 13.
[0064] An oil returning passage 31f is formed in a part of the body
portion 30 that forms the bottom surface of the gas-liquid
separation space 30f. The oil returning passage 31f allows the
refrigerating machine oil of the separated liquid-phase refrigerant
to return to the gas-phase refrigerant passage for connecting the
gas-liquid separation space 30f to the gas-phase refrigerant
outflow port 31d. The gas-phase refrigerant outflow port 31d is
connected to the suction port of the compressor 11.
[0065] On the other hand, in the liquid-phase refrigerant passage
that connects the gas-liquid separation space 30f to the
liquid-phase refrigerant outflow port 31c, an orifice 31i is
disposed as a decompressor that decompresses the refrigerant
flowing into the evaporator 14. The liquid-phase refrigerant
outflow port 31c is connected to the refrigerant inflow port of the
evaporator 14 via an inlet pipe 15a.
[0066] The evaporator 14 is a heat-absorption heat exchanger that
exchanges heat between the low-pressure refrigerant decompressed by
the nozzle passage 13a of the ejector module 13 and the ventilation
air to be blown to the vehicle interior from the blower 42, thereby
evaporating the low-pressure refrigerant to exhibit the heat
absorption effect. The evaporator 14 is disposed in a casing 41 of
an interior air-conditioning unit 40 to be described later.
[0067] Here, in the vehicle of this embodiment, the firewall 50 is
provided as a partition plate that separates the vehicle interior
from the engine room in the vehicle exterior. The firewall 50 also
has the function of reducing heat, sound, and the like to be
transferred from the engine room into the vehicle interior. The
firewall can also be called a dash panel.
[0068] As shown in FIG. 1, the interior air-conditioning unit 40 is
disposed on the vehicle inner side relative to the firewall 50.
Thus, the evaporator 14 is disposed in the vehicle interior
(interior space). A refrigerant outflow port of the evaporator 14
is connected to the refrigerant suction port 31b of the ejector
module 13 via an outlet pipe 15b.
[0069] Here, since the ejector module 13 is disposed in the engine
room (exterior space) as mentioned above, the inlet pipe 15a and
the outlet pipe 15b are disposed to pass through the firewall
50.
[0070] More specifically, the firewall 50 is provided with a
circular or rectangular through hole 50a that passes through the
engine room side and vehicle interior side of the fire wall. The
inlet pipe 15a and the outlet pipe 15b are connected to a connector
51, which is a metal member for connection, and integrated with
each other. The inlet pipe 15a and the outlet pipe 15b are arranged
to pass through a through hole 50a while being integrated together
by the connector 51.
[0071] At this time, the connector 51 is positioned on the inner
peripheral side or in the vicinity of the through hole 50a. A
packing 52 made of an elastic member is arranged in a gap between
the outer peripheral side of the connector 51 and an opening edge
of the through hole 50a. The packing 52 adopted in this embodiment
is one formed of an ethylene-propylene-diene copolymer (EPDM)
rubber, which is rubber material with excellent heat
resistance.
[0072] In this way, the packing 52 is arranged to intervene in the
gap between the connector 51 and the through hole 50a, thereby
preventing water, noise, or the like from leaking from the engine
room into the vehicle interior via the gap between the connector 51
and the through hole 50a.
[0073] Next, the interior air-conditioning unit 40 will be
described. The interior air-conditioning unit 40 is to blow out the
ventilation air having its temperature adjusted by the ejector
refrigeration cycle device 10, into the vehicle interior. The
interior air-conditioning unit 40 is disposed inside a dashboard
(instrumental panel) at the foremost portion of the vehicle
interior. Further, the interior air-conditioning unit 40
accommodates in the casing 41 forming its outer envelope, a blower
42, the evaporator 14, a heater core 44, an air mix door 46, and
the like.
[0074] The casing 41 forms an air passage for the ventilation air
to be blown into the vehicle interior. The casing 41 is formed of
resin (for example, polypropylene) with some elasticity and
excellent strength. An inside/outside air switch 43 is disposed on
the most upstream side of the ventilation air flow in the casing
41. The inside/outside air switch acts to switch between the inside
air (vehicle interior air) and the outside air (vehicle exterior
air) to guide the selected air into the casing 41.
[0075] The inside/outside air switch 43 continuously adjusts the
opening areas of an inside-air introduction port for introducing
the inside air into the casing 41 and an outside-air introduction
port for introducing the outside air thereinto by means of an
inside/outside air switching door, thereby continuously changing
the ratio of the volume of the inside air to that of the outside
air. The inside/outside air switching door is driven by an electric
actuator for the inside/outside air switching door, and the
electric actuator has its operation controlled by a control signal
output from the controller 60.
[0076] The fan (blower) 42 is disposed on the downstream side of
the ventilation air flow of the inside/outside air switch 43 so as
to blow the air drawn thereinto via the inside/outside air switch
43 toward the vehicle interior. The blower 42 is an electric blower
that drives a multi-blade centrifugal fan (sirocco fan) by the
electric motor and has the number of revolutions (blown air volume)
controlled by a control voltage output from the controller 60.
[0077] The evaporator 14 and the heater core 44 are disposed on the
downstream side of the ventilation air flow from the blower 42 in
this order with respect to the ventilation air flow. In other
words, the evaporator 14 is disposed on the upstream side of the
ventilation air flow relative to the heater core 44. The heater
core 44 is a heating heat exchanger that heats ventilation air by
exchanging heat between an engine coolant and the ventilation air
passing through the evaporator 14.
[0078] A cold-air bypass passage 45 is formed inside the casing 41
to allow the ventilation air passing through the evaporator 14 to
flow downstream while bypassing the heater core 44. The air mix
door 46 is disposed on the downstream side of the ventilation air
flow relative to the evaporator 14 and on the upstream side of the
ventilation air relative to the heater core 44.
[0079] The air mix door 46 serves as an air-volume-ratio adjustment
portion that adjusts the ratio of the volume of the air passing
through the heater core 44 to the volume of the air passing through
the cold-air bypass passage 45 in the air passing through the
evaporator 14. The air mix door 46 is driven by an electric
actuator for driving the air-mix door. The electric actuator has
its operation controlled by a control signal output from the
controller 60.
[0080] A mixing space for mixing air passing through the heater
core 44 with air passing through the cold-air bypass passage 45 is
provided on the downstream side of the air flow of the heater core
44 and on the downstream side of the air flow of the cold-air
bypass passage 45. Thus, the air mix door 46 adjusts the air volume
ratio, thereby regulating the temperature of the ventilation air
(conditioned air) which has been mixed in the mixing space.
[0081] Further, on the most downstream side of the ventilation air
flow in the casing 41, openings (not shown) are provided for
blowing the conditioned air mixed in the mixing space toward the
vehicle interior as a space to be air-conditioned. Specifically,
the openings include a face opening for blowing the conditioned air
toward the upper body of an occupant in the vehicle interior, a
foot opening for blowing the conditioned air toward the feet of the
occupant, and a defroster opening for blowing the conditioned air
toward the inner surface of a windshield of the vehicle.
[0082] The face opening, the foot opening, and the defroster
opening have their downstream sides of the ventilation air flow
connected to a face air outlet, a foot air outlet, and a defroster
air outlet (all air outlets not shown) provided in the vehicle
compartment, respectively, via ducts forming respective air
passages.
[0083] A face door for adjusting an opening area of the face
opening, a foot door for adjusting an opening area of the foot
opening, and a defroster door (all doors not shown) for adjusting
an opening area of the defroster opening are disposed on the
upstream sides of the ventilation air flow relative to the face
opening, the foot opening, and the defroster opening,
respectively.
[0084] The face door, foot door, and defroster door serve as an
air-outlet mode switch for switching an air outlet mode, and are
coupled to electric actuators for driving the air-outlet mode doors
via a link mechanism and the like and rotated in cooperation with
the respective actuators for driving the air-outlet mode doors.
Note that each of the electric actuators also has its operation
controlled by a control signal output from the controller 60.
[0085] Specifically, the air outlet modes include, for example, a
face mode, a bi-level mode, a foot mode, and a defroster mode. In
the face mode, the face opening is fully opened to blow the
ventilation air toward the upper body of the occupant. In the
bi-level mode, both the face opening and foot opening are opened to
blow the ventilation air toward the upper body and feet of the
occupant. In the foot mode, the foot opening is fully opened with
the defroster opening opened only by a small opening degree to blow
the ventilation air mainly toward the feet of the occupant in the
vehicle compartment. In the defroster mode, the defroster opening
is fully opened to blow the ventilation air toward the inner
surface of the windshield of the vehicle.
[0086] Next, the outline of an electric control unit in this
embodiment will be described using FIG. 2. The controller 60 is
configured of a known microcomputer, including CPU, ROM, and RAM,
and a peripheral circuit thereof. The controller 60 performs
various computations and processing based on an air-conditioning
control program stored in the ROM. The controller 60 controls the
operations of various electric actuators for the compressor 11,
cooling fan 12d, blower 42, and the like connected to its output
side.
[0087] A group of sensors for air-conditioning control is connected
to the controller 60 and designed to input detection values
therefrom to the controller 60. The group of sensors includes an
inside-air temperature sensor 61, an outside-air temperature sensor
62, a solar radiation sensor 63, an evaporator temperature sensor
64, a coolant temperature sensor 65, and a high-pressure side
pressure sensor 66. The inside-air temperature sensor 61 detects a
vehicle interior temperature (inside air temperature) Tr. The
outside-air temperature sensor 62 detects an outside air
temperature Tam. The solar radiation sensor 63 detects the solar
radiation amount As within the vehicle interior. The evaporator
temperature sensor 64 detects the blown-air temperature (evaporator
temperature) Tefin of the air blown from the evaporator 14. The
coolant temperature sensor 65 detects the coolant temperature Tw of
the engine coolant flowing into the heater core 44. The
high-pressure side pressure sensor 66 detects a pressure
(high-pressure side refrigerant pressure) Pd of the high-pressure
refrigerant discharged from the compressor 11.
[0088] The input side of the controller 60 is connected to an
operation panel 70 (not shown) disposed near the dashboard at the
front of the vehicle compartment. Operation signals from various
operation switches provided on the operation panel 70 are input to
the controller 60. Various operation switches provided on the
operation panel 70 include an automatic switch for setting an
automatic control operation of the vehicle air conditioner 1, a
vehicle interior temperature setting switch for setting a preset
temperature Tset of the vehicle interior, and an air-volume setting
switch for manually setting the volume of air from the blower
42.
[0089] The controller 60 in this embodiment incorporates therein
control units for controlling the operations of various control
target devices connected to its output side. In the controller 60,
a structure (hardware and software) adapted to control the
operation of each control target device serves as the control unit
for the corresponding control target device.
[0090] For example, in this embodiment, the structure for
controlling the operation of a discharge displacement control valve
of the compressor 11 configures a discharge-capacity control unit
60a for controlling a refrigerant discharge capacity of the
compressor 11. Obviously, the discharge-capacity control unit may
be configured as a separate controller with respect to the
controller 60.
[0091] Now, the operation of the vehicle air conditioner 1 with the
above-mentioned structure in this embodiment will be described
based on FIGS. 3 and 4. The flowchart of FIG. 3 shows control
processing as a main routine of the air-conditioning control
program to be executed by the controller 60. The air-conditioning
control program is executed when the automatic switch on the
operation panel 70 is turned on. Note that the respective control
steps in the flowcharts shown in FIGS. 3 and 4 configure various
function-achieving portions included in the controller 60.
[0092] In step S1, first, initialization is performed which
includes initializing a flag, a timer, and the like in a memory
circuit of the controller 60, and initial alignment of various
electric actuators described above. Note that in the initialization
at step S1, the controller may read out some of flags and
calculated values previously stored when the vehicle air
conditioner 1 is stopped or when the vehicle system is shut
down.
[0093] Then, in step S2, detection signals from the sensor group
(61 to 67) for air-conditioning control and operation signals from
the operation panel 70 are read in. In subsequent step S3, a target
air outlet temperature TAO, which is a target temperature of the
ventilation air to be blown into the vehicle interior, is
calculated based on the detection signal and operation signal read
in step S2.
[0094] Specifically, the target air outlet temperature TAO is
calculated by the following formula F1:
TAO=Kset.times.Tset-Kr.times.Tr-Kam.times.Tam-Ks.times.As+C
(F1)
where Tset is a vehicle interior preset temperature set by the
vehicle interior temperature setting switch, Tr is a vehicle
interior temperature (inside air temperature) detected by the
inside-air temperature sensor 61, Tam is the outside air
temperature detected by the outside-air temperature sensor 62, and
As is an amount of solar radiation detected by the solar radiation
sensor 63. Kset, Kr, Kam, and Ks are control gains, and C is a
constant for correction.
[0095] In subsequent steps S4 to S8, the control state of each of
the control target devices connected to the controller 60 is
determined.
[0096] In step S4, first, the number of revolutions (blowing
capacity) of the blower 42, that is, a blower motor voltage
(control voltage) applied to the electric motor of the blower 42 is
determined, and the operation proceeds to step S5. Specifically, in
step S4, a blower motor voltage is determined with reference to a
control map pre-stored in the controller 60 based on the target air
outlet temperature TAO determined in step S3.
[0097] In more detail, the blower motor voltage is determined in
such a manner as to take the substantially maximum value in an
ultralow temperature range (maximum cooling range) and an ultrahigh
temperature range (maximum heating range) of the target air outlet
temperature TAO. Furthermore, the blower motor voltage is
determined in such a manner as to gradually decrease from the
substantially maximum value as the target air outlet temperature
TAO goes from the ultralow temperature range or ultrahigh
temperature range to an intermediate temperature range.
[0098] Then, in step S5, a suction port mode, that is, a control
signal to be output to the electric actuator for the inside/outside
air switching door is determined, and then the operation proceeds
to step S6. Specifically, in step S5, the suction port mode is
determined with reference to the control map pre-stored in the
controller 60 based on the target air outlet temperature TAO.
[0099] More specifically, the suction port mode is basically
determined to be an outside-air mode for introducing the outside
air. When the target air outlet temperature TAO is in the ultralow
temperature range and a high cooling performance is desired, the
suction port mode is determined to be an inside-air mode for
introducing the inside air.
[0100] Then, in step S6, an opening degree of the air mix door 46,
that is, a control signal to be output to the electric actuator for
driving the air mix door is determined, and then the operation
proceeds to step S7.
[0101] Specifically, in step S6, the opening degree of the air mix
door 46 is calculated such that the temperature of ventilation air
blown into the vehicle interior approaches the target air outlet
temperature TAO, based on the evaporator temperature Tefin detected
by the evaporator temperature sensor 64, the coolant temperature Tw
detected by the coolant temperature sensor 65, and the target air
outlet temperature TAO.
[0102] Then, in step S7, an air outlet mode, that is, a control
signal to be output to the electric actuator for driving an
air-outlet mode door is determined, and then the operation proceeds
to step S8. Specifically, in step S8, the air outlet mode is
determined with reference to the control map pre-stored in the
controller 60 based on the target air outlet temperature TAO.
[0103] In more detail, the air outlet mode is switched from the
foot mode to the bi-level mode and then the face mode in this order
as the target air outlet temperature TAO decreases from a
high-temperature range to a low-temperature range.
[0104] Next in step S8, the refrigerant discharge capacity of the
compressor 11, that is, a control current output to the discharge
displacement control valve of the compressor 11 is determined, and
the operation proceeds to step S9. The details of step S8 will be
described below using the flowchart of FIG. 4.
[0105] In step S81 of FIG. 4, it is determined whether the
compressor 11 is at startup or not. More specifically, in step S81,
when a value of the control current output to the discharge
displacement control valve is zero (0) in determination, the
compressor 11 is determined to be at startup. When the compressor
11 is determined not to be at startup in step S81, the operation
proceeds to step S82. In contrast, when the compressor 11 is
determined to be at startup, the operation proceeds to step
S83.
[0106] Next in step S82, the refrigerant discharge capacity of the
compressor 11 in the normal control, that is, a control current
output to the discharge displacement control valve of the
compressor 11 is determined, and the operation proceeds to step S9.
Specifically, in step S82, a target evaporator outlet air
temperature TEO of the evaporator 14 is determined with reference
to the control map pre-stored in the controller 60 based on the
target air outlet temperature TAO.
[0107] A target refrigerant discharge capacity of the compressor 11
is determined such that an evaporator temperature Tef in approaches
the target evaporator outlet air temperature TEO using a feedback
control method, based on a deviation between the target evaporator
outlet air temperature TEO and the evaporator temperature Tefin
detected by the evaporator temperature sensor.
[0108] Next in step S83, the refrigerant discharge capacity of the
compressor 11 at startup, that is, a control current output to the
discharge displacement control valve of the compressor 11 is
determined, and the operation proceeds to step S9. Specifically, in
step S83, the target refrigerant discharge capacity of the
compressor 11 is determined at the startup, in the same way as in
step S82. As indicated by a thick solid line in the control
characteristic diagram described in step S83 of FIG. 4, an actual
refrigerant discharge capacity is gradually increased until the
target refrigerant discharge capacity is reached.
[0109] In more detail, in step S83, the refrigerant discharge
capacity is increased in such a manner that an increase amount
(capacity increase degree) in the refrigerant discharge capacity
per predetermined time period (predetermined reference time period)
is lower than a predetermined reference capacity increase amount
(reference capacity increase degree). Furthermore, in this
embodiment, the reference capacity increase amount is defined as
the maximum capacity increase amount per predetermined time period
enabled by the compressor 11. The maximum capacity increase is
represented by a slope of a dashed line in the control
characteristic diagram described in step S83 of FIG. 4.
[0110] In other words, in step S83 of this embodiment, it can be
expressed that the refrigerant discharge capacity is gradually
increased in such a manner that an actual refrigerant discharge
capacity of the compressor 11 does not reach the target refrigerant
discharge capacity until the predetermined time elapses.
Furthermore, it can be expressed that an actual refrigerant
discharge capacity of the compressor 11 is gradually increased
until it reaches the target refrigerant discharge capacity, over a
longer time than the time period during which the compressor 11
exhibits the maximum capacity increase.
[0111] Then, in step S9 shown in FIG. 3, control signals and
control voltages are output to various control target devices
connected to the output side of the controller 60 so as to achieve
the control state determined in the above-mentioned steps S4 to S8.
In subsequent step S10, the controller is on standby for a control
cycle T, and if the control cycle t is determined to elapse, the
operation is returned to step S2.
[0112] That is, in the air-conditioning control program executed by
the controller 60, a routine that includes reading a detection
signal and an operation signal, determining the control state of
each control target device, and outputting a control signal and a
control voltage to each control target device in this order is
repeated until the stopping of the operation of the vehicle air
conditioner 1 is requested. The air-conditioning control program is
executed to allow the refrigerant to flow in the ejector
refrigeration cycle device 10 as indicated by thick solid arrows
shown in FIG. 1.
[0113] That is, the high-temperature and high-pressure refrigerant
discharged from the compressor 11 flows into the condensing portion
12a of the radiator 12. The refrigerant flowing into the condensing
portion 12a exchanges heat with the outside air blown by the
cooling fan 12d and dissipates heat therefrom to condense itself.
The refrigerant condensed in the condensing portion 12a is
separated into gas and liquid phases by the receiver 12b. The
liquid-phase refrigerant of the gas and liquid phases refrigerants
separated by the receiver 12b exchanges heat with the outside air
blown from the cooling fan 12d in the supercooling portion 12c, and
further dissipates heat therefrom to be converted into the
supercooled liquid-phase refrigerant.
[0114] The supercooled liquid-phase refrigerant flowing out of the
supercooling portion 12c of the radiator 12 is isentropically
decompressed by the nozzle passage 13a formed between the inner
peripheral surface of the decompression space 30b and the outer
peripheral surface of the passage formation member 35 in the
ejector module 13, and is then injected therefrom. At this time,
the refrigerant passage area of the minimum passage area portion in
the decompression space 30b is adjusted such that the degree of
superheat of the refrigerant on the outlet side of the evaporator
14 approaches a reference degree of superheat.
[0115] The refrigerant flowing out of the evaporator 14 is drawn
into the ejector module 13 from the refrigerant suction port 31b by
the suction effect of an injection refrigerant injected from the
nozzle passage 13a. The injection refrigerant injected from the
nozzle passage 13a and the suction refrigerant drawn via the
suction passage 13b flow into and are merged in the diffuser
passage 13c.
[0116] In the diffuser passage 13c, the kinetic energy of the
refrigerant is converted into pressure energy thereof by the
enlarged refrigerant passage area. Thus, while the injection
refrigerant and suction refrigerant are being mixed together, the
mixed refrigerant has its pressure increased. The refrigerant
flowing out of the diffuser passage 13c is separated by the
gas-liquid separation space 30f into gas and liquid phase
refrigerants. The liquid-phase refrigerant separated by the
gas-liquid separation space 30f is decompressed by an orifice 31i
and then flows into the evaporator 14.
[0117] The refrigerant flowing into the evaporator 14 absorbs heat
from the ventilation air blown from the blower 42 to evaporate
itself. In this way, the ventilation air is cooled. On the other
hand, the gas-phase refrigerant separated by the gas-liquid
separation space 30f flows out of the gas-phase refrigerant outflow
port 31d, and is then drawn into and compressed again by the
compressor 11.
[0118] In the interior air-conditioning unit 40, the ventilation
air cooled by the evaporator 14 flows into a ventilation passage on
the heater core 44 side and the cold-air bypass passage 45
depending on the opening degree of the air mix door 46. The cold
air flowing into the ventilation passage on the heater core 44 side
is reheated when passing through the heater core 44, and then mixed
with a cold air passing through the cold-air bypass passage 45 in a
mixing space. The conditioned air having its temperature adjusted
in the mixing space is blown into the vehicle interior via the
respective air outlets.
[0119] As mentioned above, the vehicle air conditioner 1 in this
embodiment can perform air-conditioning of the vehicle interior.
Further, in the ejector refrigeration cycle device 10 of this
embodiment, the refrigerant pressurized by the diffuser passage 13c
is drawn into the compressor 11, thus enabling the reduction in the
driving power for the compressor 11, thereby improving the
coefficient of performance (COP) of the cycle.
[0120] Further, in the ejector module 13 of this embodiment, the
supercooled liquid-phase refrigerant flows into and swirls in the
swirl space 30a, whereby the refrigerant pressure on the swirl
center side of the swirl space 30a is reduced to a pressure at
which the refrigerant becomes a saturated liquid-phase refrigerant,
or a pressure at which the refrigerant is decompressed and boiled
(causing cavitation). The gas-liquid two-phase refrigerant in which
the majority of gas-phase refrigerant is located on the swirl
central side flows into the nozzle passage 13a.
[0121] Thus, the boiling of the refrigerant in the nozzle passage
13a can be promoted due to wall boiling caused by the friction
between the refrigerant and the wall surface of the nozzle passage
13a as well as interface boiling caused by a boiling nucleus
generated by the cavitation of the refrigerant on the swirl central
side. As a result, the energy conversion efficiency can be improved
when converting the pressure energy of the refrigerant into the
velocity energy thereof in the nozzle passage 13a.
[0122] For example, when the outside air temperature is relatively
high at start-up of the ejector refrigeration cycle device 10, the
gas-phase refrigerant sometimes remains in the radiator. Thus, when
the ejector refrigeration cycle device 10 is started up at a high
outside-air temperature and the like, the gas-liquid two-phase
refrigerant not sufficiently cooled might flow out of the radiator
12 at start-up of the compressor 11. The gas-liquid two-phase
refrigerant might flow into the refrigerant inflow passage 31e of
the ejector module 13.
[0123] It should be noted that the term "start-up of the compressor
11" as used in this embodiment includes a period of time
immediately after start-up of the compressor 11, at least from when
the compressor 11 does not exhibit its refrigerant discharge
capacity till when the compressor 11 exhibits the target
refrigerant discharge capacity.
[0124] In the ejector module 13 of this embodiment, in order to
appropriately swirl the supercooled liquid-phase refrigerant in the
swirl space 30a, the passage cross-sectional area of the
refrigerant inflow passage 31e is set to a relatively small value
as mentioned above.
[0125] Thus, if the gas-liquid two-phase refrigerant flows into the
refrigerant inflow passage 31e, the gas-liquid two-phase
refrigerant circulating through the refrigerant inflow passage 31e
flows at a high velocity, as compared to when a supercooled
liquid-phase refrigerant with a higher density flows in, which
might cause friction noise when it circulates through the
refrigerant inflow passage 31e. Further, if the friction noise
resonates with the gas-phase refrigerant eccentrically located in a
columnar shape on the center side of the swirl space, a so-called
air column resonance might make significant noise.
[0126] In contrast, in the ejector refrigeration cycle device 10 of
this embodiment, as described in control step S83, the refrigerant
discharge capacity is increased such that the increase amount in
the refrigerant discharge capacity per predetermined time period is
lower than the reference capacity increase amount at start-up of
the compressor 11.
[0127] Therefore, even if the gas-liquid two-phase refrigerant
flows into the refrigerant inflow passage 31e, the flow velocity of
the gas-liquid two-phase refrigerant is prevented from becoming
high, which can reduce the friction noise that would be caused when
the gas-liquid two-phase refrigerant circulates through the
refrigerant inflow passage 31e. As a result, the noise generated
from the ejector module 13 can be reduced at start-up of the
compressor 11.
[0128] This embodiment adopts as the reference capacity increase
amount, the maximum capacity increase amount per predetermined time
period that is determined by a capacity inherent to the compressor
11. Thus, the noise generated from the ejector module 13 can be
surely reduced when the refrigerant discharge capacity is increased
naturally by the maximum capacity increase amount at start-up of
the compressor 11.
[0129] Further, the reference capacity increase amount is set to
such a level of the capacity increase that prevents noise generated
from the ejector module 13 at start-up of the compressor 11 from
being harsh on the user's ear. Thus, noise generated from the
ejector module 13 can be effectively reduced.
Second Embodiment
[0130] As shown in the entire configuration diagram of FIG. 5, in
this embodiment, a flow-rate adjustment valve 16 is added to the
refrigerant flow path that leads from the refrigerant outlet of the
radiator 12 to the refrigerant inflow port 31a of the ejector
module 13, as compared to the ejector refrigeration cycle device 10
of the first embodiment.
[0131] The flow-rate adjustment valve 16 is an inflow rate
adjustment portion that adjusts the flow rate of the inflow
refrigerant flowing into the refrigerant inflow passage 31e forming
the swirling-flow generating portion. More specifically, the
flow-rate adjustment valve 16 includes a valve body capable of
changing the refrigerant passage area and an electric actuator for
displacing the valve body. Further, the flow-rate adjustment valve
16 has its operation controlled by a control voltage output from
the controller 60.
[0132] Thus, as shown in the block diagram of FIG. 6, the output
side of the controller 60 in this embodiment is connected to the
flow-rate adjustment valve 16. In this embodiment, the structure
for controlling the operation of the flow-rate adjustment valve 16
serving as the inflow rate adjustment portion configures an inflow
rate control unit 60b. The structures and operations of other
components are the same as those in the first embodiment.
[0133] In the vehicle air conditioner 1 of this embodiment, in step
S8' of the flowchart shown in FIG. 7, the refrigerant discharge
capacity of the compressor 11 is determined in the same way as the
normal control in control step S82 described in the first
embodiment.
[0134] Further, in step S85, a valve opening degree of the
flow-rate adjustment valve 16, that is, a control progress state to
be output to the flow-rate adjustment valve 16 is determined, and
then the operation proceeds to step S9. In step S85, if not at
start-up of the compressor 11, the valve opening degree of the
flow-rate adjustment valve 16 is maximized (in a fully open state).
In contrast, at start-up of the compressor 11, the valve opening
degree of the flow-rate adjustment valve 16 is gradually increased
to attain a refrigerant inflow rate indicated by a thick solid line
in the control characteristic diagram of FIG. 8.
[0135] In more detail, in step S85, at start-up of the compressor
11, the refrigerant inflow rate is increased in such a manner that
the increase amount (flow-rate increase degree) in the refrigerant
inflow rate per predetermined time period (predetermined reference
time period) is lower than the predetermined reference flow-rate
increase amount (reference flow-rate increase degree). Furthermore,
in this embodiment, the reference flow-rate increase amount is
defined as the maximum flow-rate increase amount per predetermined
time period enabled by the flow-rate adjustment valve 16.
[0136] That is, the maximum flow-rate increase amount corresponds
to a flow-rate increase amount obtained when the valve opening
degree of the flow-rate adjustment valve 16 is maximized at
start-up of the compressor 11. The maximum flow-rate increase
amount is represented by a slope of a dashed line in the control
characteristic diagram described in FIG. 8.
[0137] In other words, in step S85 of this embodiment, it can be
expressed that the valve opening degree (refrigerant inflow rate)
is gradually increased in such a manner as to prevent the valve
opening degree of the flow-rate adjustment valve 16 from being
maximized until the predetermined time elapses at start-up of the
compressor 11. Furthermore, it can also be expressed that the
refrigerant inflow rate is gradually increased over a longer time
than the time period during which the valve opening of the
flow-rate adjustment valve 16 is maximized.
[0138] The operations of other components are the same as those in
the first embodiment. Therefore, the vehicle air conditioner 1 of
this embodiment can also perform the air-conditioning of the
vehicle interior in the same manner as that in the first
embodiment, and thus can obtain the same effects as those in the
first embodiment.
[0139] Furthermore, in the ejector refrigeration cycle device 10 of
this embodiment, as described in control step S85, the refrigerant
inflow rate is increased such that the increase amount in the
refrigerant inflow rate per predetermined time period is lower than
the reference flow-rate increase amount at start-up of the
compressor 11.
[0140] Therefore, even if the gas-liquid two-phase refrigerant
flows into the refrigerant inflow passage 31e, the flow velocity of
the gas-liquid two-phase refrigerant is prevented from becoming
high, which can reduce the friction noise that would be caused when
the gas-liquid two-phase refrigerant circulates through the
refrigerant inflow passage 31e. As a result, like the first
embodiment, the noise generated from the ejector module 13 can be
reduced at start-up of the compressor 11.
[0141] This embodiment adopts as the reference flow-rate increase,
the maximum flow-rate increase amount per predetermined time period
obtained when the valve opening degree of the flow-rate adjustment
valve 16 is maximized. Thus, at start-up of the compressor 11, the
noise generated from the ejector module 13 can be surely reduced
when the valve opening degree of the flow-rate adjustment valve 16
is maximized.
[0142] Further, the reference flow-rate increase amount is set to
such a level of the flow-rate increase amount that prevents noise
generated from the ejector module 13 from being harsh on the user's
ear at start-up of the compressor 11, so that noise generated from
the ejector module 13 can be effectively reduced.
Third Embodiment
[0143] In this embodiment, as shown in the entire configuration
diagram of FIG. 9, the flow-rate adjustment valve 16 is disposed in
the refrigerant flow path that leads from the gas-phase refrigerant
outflow port 31d of the ejector module 13 to the suction port of
the compressor 11, as compared to in the second embodiment. The
structures and operations of other components are the same as those
of the second embodiment.
[0144] Therefore, the vehicle air conditioner 1 of this embodiment
can also perform the air-conditioning of the vehicle interior in
the same manner as that in the first embodiment, and thus can
obtain the same effects as those in the first embodiment. Further,
like the second embodiment, the noise generated from the ejector
module 13 can be reduced at start-up of the compressor 11.
Other Embodiments
[0145] The present disclosure is not limited to the above-mentioned
embodiments, and various modifications and changes can be made to
those embodiments in the following way without departing from the
scope and spirit of the present disclosure. [0146] (1) In the
above-mentioned first embodiment, as illustrated in control step
S83 of FIG. 4, the refrigerant discharge capacity of the compressor
11 is increased in stages at start-up of the compressor 11 by way
of example. However, the control performed when the refrigerant
discharge capacity of the compressor 11 is increased is not limited
thereto. That is, as long as an increase amount in the refrigerant
discharge capacity per predetermined time period is lower than the
reference capacity increase, the refrigerant discharge capacity of
the compressor 11 may be continuously increased, for example, in
the same manner as in the control characteristic diagram of FIG.
8.
[0147] The same goes for the refrigerant inflow rate described in
the second embodiment. That is, in the same manner as that
illustrated in step S83 of the control characteristic diagram in
FIG. 4, the refrigerant inflow rate may be increased in stages.
[0148] (2) The above-mentioned second embodiments employs, for
example, the electric flow-rate adjustment valve 16 as the inflow
rate adjustment portion. However, the inflow rate adjustment valve
is not limited thereto. For example, a plurality of refrigerant
passages and a plurality of on/off valves (electromagnetic valves)
for opening and closing the respective refrigerant passages may
form the inflow rate adjustment valve. Thus, the refrigerant inflow
rate can be adjusted in stages, depending on the number of on/off
valves for opening the refrigerant passages.
[0149] Alternatively, a flow-rate adjustment mechanism may be
adopted which includes a displacement member to be displaced
depending on the temperature and pressure of the refrigerant
circulating through a predetermined part in the cycle, and a valve
body coupled to the displacement member and adapted to change its
refrigerant passage area. The flow-rate adjustment mechanism
changes its refrigerant passage area through such a mechanical
mechanism. Specifically, the flow-rate adjustment mechanism can be
employed which is adapted to detect the degree of superheat of the
refrigerant on the outlet side of the radiator 12 based on the
temperature and pressure of the refrigerant on the outlet side of
the radiator 12 and to increase the valve opening degree with
decreasing degree of superheat detected. [0150] (3) In the
above-mentioned embodiments, for example, as shown in control step
S81 of the first embodiment, whether the compressor 11 is at
startup or not is determined based on a value of the control
current output to the discharge displacement control valve.
However, the way to determine whether the compressor 11 is at
startup or not is not limited thereto.
[0151] For example, whether the compressor 11 is at startup or not
may be determined using a pressure (high-pressure side refrigerant
pressure) Pd of the refrigerant circulating through the refrigerant
flow path that leads from the outlet side of the compressor 11 to
the refrigerant inflow port 31a side of the ejector module 13. When
a revolution indicator for detecting the number of revolutions of
the compressor 11 is installed, whether or not the compressor 11 is
at startup may be determined based on a detected value of the
revolution indicator. [0152] (4) Respective components forming the
ejector refrigeration cycle device 10 are not limited to those
disclosed in the above-mentioned embodiments.
[0153] For example, the above-mentioned embodiments employ the
variable displacement compressor as the compressor 11, but the
compressor 11 is not limited thereto. The compressor 11 for use may
be a fixed displacement compressor that is driven by a rotational
driving force output from the engine via an electromagnetic clutch,
a belt, etc.
[0154] The fixed displacement compressor may adjust the refrigerant
discharge capacity by changing an operating rate of the compressor
through switching between the connection and disconnection of the
electromagnetic clutch. The compressor 11 for use may be an
electric compressor that adjusts the refrigerant discharge capacity
by changing the number of revolutions of the electric motor.
[0155] For example, in the above-mentioned embodiments, the
radiator 12 employs a sub-cool type heat exchanger by way of
example. Alternatively, a standard radiator configured of only the
condensing portion 12a may be adopted. Further, a reservoir
(receiver) may be employed along with the standard radiator. The
reservoir separates the refrigerant dissipating its heat in the
radiator, into gas and liquid phase refrigerants, and stores an
excessive liquid-phase refrigerant.
[0156] The respective components forming the ejector module 13 are
not limited to those disclosed in the above-mentioned embodiments.
For example, the components of the ejector module 13, including the
body portion 30 and the passage formation member 35, are made of
metal, but are not limited thereto and may alternatively be formed
of resin.
[0157] Further, in the ejector module 13 of the above-mentioned
embodiments, the orifice 31i is provided by way of example.
However, the orifice 31i may be abolished, and a decompression
portion may be disposed in the inlet pipe 15a. Such a decompression
portion can be an orifice, a capillary tube, or the like.
[0158] Further, the above-mentioned embodiments employ the ejector
module 13 of the gas-liquid separator integrated ejector by way of
example. However, it is obvious that a standard ejector that does
not include a gas-liquid separator integrated therewith may be
employed as the ejector. [0159] (5) In the above-mentioned
embodiments, the ejector module 13 is disposed within the engine
room by way of example, but may be disposed on the vehicle interior
side relative to the firewall 50.
[0160] Further, the ejector module 13 may be disposed on the inner
peripheral side of the through hole 50a of the firewall 50. In this
case, a part of the ejector module 13 is disposed on the engine
room side, and the other part is disposed on the vehicle interior
side. Thus, a packing exhibiting the same function as in the first
embodiment is desirably disposed in a gap between the outer
peripheral side of the ejector module 13 and the opening edge of
the through hole 50a. [0161] (6) Although in the above-mentioned
embodiments, the ejector refrigeration cycle device 10 according to
the present disclosure is applied to the vehicle air conditioner 1
by way of example, the applications of the ejector refrigeration
cycle device 10 in the present disclosure are not limited thereto.
For example, the ejector refrigeration cycle device 10 may be
applied to a refrigerator-freezer for a vehicle. The ejector
refrigeration cycle device 10 is not limited to the application for
vehicles, but may be applied to a stationary air conditioner, a
cooling storage, and the like.
* * * * *