Refrigeration – Automatic control – Refrigeration producer
Reexamination Certificate
2001-08-10
2003-06-10
Tanner, Harry B. (Department: 3744)
Refrigeration
Automatic control
Refrigeration producer
C062S324600
Reexamination Certificate
active
06574976
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to and claims priority from Japanese Patent Applications No. 2000-244614 filed on Aug. 11, 2000, and No. 2001-156033 filed on May 24, 2001, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a refrigerant cycle system having a hot-gas heater function using an evaporator as a radiator, and to a valve device used for the refrigerant cycle system. In the refrigerant cycle system, the hot-gas heater function is obtained by directly introducing gas refrigerant (hot gas) discharged from a compressor into the evaporator while bypassing a condenser.
2. Description of Related Art
U.S. Pat. No. 5,291,941 discloses a refrigerant cycle system having a heating function due to a hot-gas bypass. As shown in
FIG. 12
, a hot-gas bypass passage
118
is provided in this conventional system, and a heating decompression unit
117
and a heating solenoid valve
115
A are provided in the hot-gas bypass passage
118
. In addition, a cooling solenoid valve
115
is provided in a refrigerant passage through which refrigerant discharged from a compressor
110
flows into a condenser
119
. Here, gas refrigerant discharged from the compressor
110
flows directly into an evaporator
128
through the hot-gas bypass passage
118
while bypassing the condenser
119
and the like. Further, the hot-gas bypass passage
118
and the refrigerant passage of the condenser
119
are selectively opened and closed by the cooling solenoid valve
115
and the heating solenoid valve
115
A. Within an air-conditioning unit
126
disposed in a passenger compartment
125
, a hot-water-type heating heater core
129
is disposed at a downstream air side of the evaporator
128
. In a heating mode in winter, when a temperature of hot water circulating the heating heater core
129
is lower than a predetermined temperature, for example, when an engine
112
is started for warming up, high-temperature gas refrigerant (hot gas) discharged from the compressor
110
flows through the hot-gas bypass passage
118
, and is directly introduced into the evaporator
128
after being decompressed by the heating decompression unit
117
. Therefore, in the heating mode, heat is radiated from refrigerant to air in the evaporator
128
, and the heating function for heating air can be obtained.
On the other hand, in a cooling mode, the high-temperature gas refrigerant discharged from the compressor
110
flows into the condenser
119
by closing the heating solenoid valve
115
A and opening the cooling solenoid valve
115
.
In the above-described system, however, both solenoid valves
115
,
115
A are used for switching refrigerant passages in the cooling mode and the heating mode. Further, a check valve
121
for preventing refrigerant in the hot-gas bypass passage
118
from flowing into the condenser
119
in the heating mode is provided separately from the solenoid valves
115
,
115
A. Accordingly, the number of components is increased, and production cost is increased in this system.
Further, a long piping is required for the hot-gas bypass passage
118
extending from an outlet of the heating solenoid valve
115
A disposed around the compressor
110
in an engine compartment
124
, to an inlet of the evaporator
128
in the passenger compartment
125
. Therefore, mounting performance of the system on a vehicle is decreased.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the present invention to provide a refrigerant cycle system having a hot-gas heater function, which has a simple integrated structure of a valve device.
According to the present invention, in a refrigerant cycle system which switches an operation mode between a cooling mode where air is cooled by evaporating low-pressure refrigerant in an evaporator and a heating mode where air is heated in the evaporator by using gas refrigerant directly introduced from a compressor, a valve device includes a solenoid valve for opening and closing a refrigerant passage between a discharge side of the compressor and a condenser cooling and condensing refrigerant in the cooling mode, a differential pressure valve disposed to be opened by a pressure difference between the discharge side of the compressor and a side of the condenser, generated when the solenoid valve is closed, in such a manner that gas refrigerant discharged from the compressor is directly introduced into the evaporator when the differential pressure valve is opened, and a check valve disposed to prevent refrigerant at the discharge side of the compressor from flowing into the condenser when the differential pressure valve is opened. In the valve device, the solenoid valve, the differential pressure valve and the check valve are integrated by a housing member to construct an integrated structure. Accordingly, at least three kinds of valves, that is, the solenoid valve, the differential pressure valve and the check valve can be used as the integrated structure, thereby reducing an arrangement space of the valve device and the number of attachment steps. Further, the refrigerant cycle system operates by a combination of the one solenoid valve and the one differential pressure valve. Since the differential pressure valve can be made smaller, lighter and simpler than the solenoid valve in addition to the integration of three kinds of valves, the valve device can be produced in low cost while having a simple structure.
Furthermore, because the differential pressure valve is opened by the pressure difference between the discharge side of the compressor and the condenser, generated when the solenoid valve is closed, both the solenoid valve and the differential pressure valve are not closed at the same time. Therefore, it can prevent a refrigerant cycle circuit of the refrigerant cycle system from being closed when the compressor operates, and it can prevent the refrigerant cycle circuit from failing.
Preferably, in the valve device, the housing member is disposed to define a first refrigerant passage connected to the discharge side of the compressor, a second refrigerant passage connected to a refrigerant inlet side of the condenser, a third refrigerant passage connected to a refrigerant inlet side of the evaporator, and a fourth refrigerant passage connected to a refrigerant outlet side of the condenser. The solenoid valve is disposed to open and close a communication between the first and second refrigerant passages, and the differential pressure valve is disposed to open and close a communication between the first and third refrigerant passages. Further, the housing member is disposed to have therein a heating decompression means for decompressing gas refrigerant flowing from the first refrigerant passage to the third refrigerant passage when the differential pressure valve is opened, and to have therein a communication passage through which the fourth refrigerant passage communicates with a downstream refrigerant side of the heating decompression means. In addition, the check valve is provided in the communication passage. Accordingly, the fourth refrigerant passage connected to the outlet side of the condenser can communicate with the downstream refrigerant side of the heating decompression means through the communication passage in the housing member. That is, the downstream refrigerant side of the heating decompression means and the communication passage connected to the outlet side of the condenser can be joined to each other in the housing member. Therefore, it is possible to connect the third refrigerant passage of the housing member and the inlet side of the evaporator by only using a single low-pressure pipe.
REFERENCES:
patent: 5291941 (1994-03-01), Enomoto et al.
patent: 5934097 (1999-08-01), Karl
patent: 6076366 (2000-06-01), Takano et al.
patent: 6125643 (2000-10-01), Noda et al.
patent: 6244060 (2001-06-01), Takano et al.
patent: 6286327 (2001-09-01), Karl
patent: 0895884 (1999-02-01), None
patent: 09109669 (1997-04-
Hirose Tetsuo
Ochi Ikuo
Takagi Noboru
Takano Yoshiaki
Yamamoto Yasuhiro
Denso Corporation
Harness Dickey & Pierce PLC
Tanner Harry B.
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