Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2000-11-08
2002-08-13
Wayner, William (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S090000, C062S160000
Reexamination Certificate
active
06430951
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an automotive air conditioner for conditioning air in a room of an automobile. The automotive air conditioner of the present invention is effectively applied to an automobile which does not have a surplus heat source as, for example, an electric automobile.
2. Related Art
Usually, an automotive air conditioner makes use, in order to heat air, of heat from cooling water for an engine for driving an automobile. However, heating of air is performed using a heat pump when the amount of heat of cooling water for an engine is insufficient or when an automobile does not originally have engine cooling water such as an electric automobile.
For example, in an automotive air application Ser. No. 60-219114, a flow of refrigerant is changed over by means of a four-way valve such that an inside heat exchanger is used either as an evaporator to cool air or as a condenser to heat air.
With the automotive air conditioner wherein cooling operation and heating operation are performed alternatively by changing over of a four-way valve in this manner, since the single heat exchanger changes its function immediately between a function of an evaporator and another function of a condenser, there is the possibility that, particularly when the function is changed over, a large amount of moisture may be blasted from a surface of the inside heat exchanger toward the inside of the room of the automobile.
In particular, water condensed on a surface of the inside heat exchanger during cooling operation is evaporated from the surface of the inside heat exchanger as a result of changing over to heating operation and then carried into the room of the automobile by a blower. Such blasting of a large amount of water will instantaneously fog a windshield and/or window glass. The fog will make an obstacle to a field of view in driving the automobile and is very inconvenient.
Accumulator cycles are conventionally known wherein a subcooling control valve is disposed on the downstream side of a refrigerant condenser to obtain a subcooled condition of refrigerant.
An exemplary one of subcooling control valves is disclosed, for example, in Japanese Utility Model Laid-Open Application No. Showa 55-85671 and is shown in FIG.
100
. Referring to
FIG. 100
, the subcooling control valve
1100
includes a valve body
1103
for opening or closing a throttle section
1102
by operation of a diaphragm
1101
, a regulating spring
1104
for normally biasing the valve body
1103
to open the throttle section
1102
, and a temperature sensitive tube
1105
for converting a variation of temperature of refrigerant on the downstream side of a refrigerant condenser (not shown) into a variation of pressure.
The displacement of the valve body
1103
is adjusted by the balance between the pressure in the temperature sensitive tube
1105
which acts upon the upper side of the diaphragm
1101
via a capillary tube
1106
and the high pressure of the refrigerant and the biasing force of the regulating spring
1104
which both act upon the lower side of the diaphragm
1101
, and the opening of the throttle section
1102
depends upon the displacement of the valve body
1103
.
However, in the subcooling control valve
1100
described above, since the biasing force of the regulating spring
1104
is set in advance so that a predetermined subcooling degree (for example, 5 to 10° C.) may be obtained within the refrigerant condenser, when it is tried to construct such a novel subcooling cycle as shown in
FIG. 101
or
1017
using the subcooling control valve
1100
, such subjects to be solved as described below are involved.
Referring first to
FIG. 101
, the subcooling cycle shown constitutes a heat pump cycle for an automotive air conditioner and includes a refrigerant compressor
1200
, an interior condenser
1202
disposed in a duct
1201
which introduces blast air into the room of the automobile, a subcooling control valve
1100
, an interior evaporator
1203
disposed in the duct
1201
on the upstream side of the interior condenser
1202
, an evaporation pressure regulating valve
1204
, an exterior evaporator
1205
disposed on the outside of the duct
1201
, an accumulator
1206
, a bypass passageway
1207
for bypassing the interior evaporator
1203
and the evaporation pressure regulating valve
1204
, and a solenoid valve
1208
for opening or closing the bypass passageway
1207
.
Now, if the bypass passageway
1207
is closed by the solenoid valve
1208
so that the refrigerant flowing out through the subcooling control valve
1100
is introduced into the interior evaporator
1203
, then air introduced into the duct
1201
by a fan
1209
is cooled when it passes through the interior evaporator
1203
, and thereafter, the air is heated when it passes through the interior condenser
1202
, and then it blown out into the room of the vehicle. In this instance, when the saturation temperature of the refrigerant flowing through the interior condenser
1202
is 50° C. or around it, as cool air of a temperature close to 0° C. cooled by the interior evaporator
1203
is blown to the interior condenser
1202
, ideally a subcooling degree of the temperature of 50° C. or so can be obtained at the interior condenser
1202
.
On the other hand, if the bypass passageway
1207
is opened by the solenoid valve
1208
to allow the refrigerant flowing out from the subcooling control valve
1100
to be introduced into the exterior evaporator
1205
while an internal air mode is set so that air in the automobile room of a temperature of 30° C. or around it is introduced into the duct
1201
, then the air introduced in the duct
1201
is blown to the interior condenser
1202
while keeping its temperature (30° C.) without being cooled by the interior evaporator
1203
. Consequently, only a subcooling degree of the temperature of 20° C. or so to the utmost can be obtained at the interior condenser
1202
.
In the meantime, the subcooling cycle shown in
FIG. 102
constitutes a refrigerating cycle for an automotive air conditioner and includes an exterior evaporator
1210
on the upstream side of an interior condenser
1202
, and an air mixing damper
1211
for adjusting the amount of draft air to the interior condenser
1202
. When the air mixing damper
1211
is opened or closed, cooling air of the temperature of 0° C. or around it cooled by an interior evaporator
1203
is blown to or not blown to the interior condenser
1202
.
For example, when the air mixing damper
1211
fully opens the interior condenser
1202
(the position indicated by full lines in
FIG. 102
) so that cool air of the temperature of 0° C. or around it is blown to the interior condenser, if the saturation temperature of the refrigerant flowing through the interior condenser
1202
is 50° C. or around it, a subcooling degree of the temperature ideally of 50° C. or around it can be obtained.
On the other hand, when the air mixing damper
1211
closes the interior condenser
1202
(the position indicated by chain lines in FIG.
102
), cool air is not blown to the interior condenser
1202
, and the interior condenser
1202
acts as a mere refrigerant passageway. Consequently, if the external air temperature (the temperature of wind blown to the exterior condenser
1210
) is 30° C., then while the saturation temperature of the refrigerant flowing through the exterior condenser
1201
and the interior condenser
1202
is 50° C., only a subcooling degree of the temperature of 20° C. or so can be obtained even if the refrigerant is cooled ideally to 30° C. of the external air temperature.
Accordingly, where the biasing force of the regulating spring
1104
of the subcooling control valve
1100
is set in the subcooling cycles shown in
FIGS. 101 and 102
so that the subcooling degree of 20° C. may be obtained at the interior condenser
1202
, the subcooling control valve
1100
tends to control the subcooling degree of 20° C. even when cool wind of the temperature of 0° C. or around it cooled by the interior
Fujiwara Ken-ichi
Iritani Kunio
Isaji Akira
Isaji Tamiko
Numazawa Shigeo
Denso Corporation
Harness & Dickey & Pierce P.L.C.
Isaji Tamiko
Wayner William
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