# US 6,279,331 B1 · Vehicular refrigerating cycle with a bypass line

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- Number: US 6,279,331 B1
- Document ID: US6279331B1
- Status: Granted
- Kind: B1
- Application number: 09/543,538
- Filed: 2000-04-05
- Granted: 2001-08-28
- Earliest claimed: 1999-05-10
- Assignees: Tgk Co., Ltd.
- Inventors: Hisatoshi Hirota
- Web page: https://patentgrep.com/patent/US6279331B1

## CPC

- F04B 27/1804: {Controlled by crankcase pressure}
- B60H 1/00885: {Controlling the flow of heating or cooling liquid, e.g. valves or pumps (B60H1/00899 takes precedence; constructions of valves B60H1/00485)}
- B60H 1/3205: {Control means therefor}
- B60H 1/3211: {for increasing the efficiency of a vehicle refrigeration cycle}
- B60H 1/3219: {for improving the response time of a vehicle refrigeration cycle}
- F25B 41/20: Disposition of valves, e.g. of on-off valves or flow control valves (expansion valves F25B41/31)
- F25B 41/24: Arrangement of shut-off valves for disconnecting a part of the refrigerant cycle, e.g. an outdoor part
- F25B 49/022: {Compressor control arrangements}
- B60H 2001/325: {of the refrigerant at a compressing unit}
- B60H 2001/3252: {of the refrigerant at an evaporating unit}
- B60H 2001/3255: {related to temperature}
- B60H 2001/3263: {of the refrigerant at an evaporating unit}
- B60H 2001/3275: {to control the volume of a compressor}
- F04B 2027/1813: {Crankcase pressure}
- F04B 2027/1831: {between crankcase and suction chamber}
- F04B 2027/189: {between crankcase and discharge chamber}
- F25B 2400/0403: for condensers
- F25B 2400/0411: for expansion valves or capillary tubes
- F25B 2400/16: Receivers
- F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F)
- B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS

## Abstract

A vehicular refrigerating cycle with a by-pass line is provided, whereby even in an environment of extremely low temperature with the refrigerating cycle left at rest after being operated in cooling mode, refrigerant accumulated in a condenser can be driven out of the condenser to provide subsequent heating functions by an evaporator in a prescribed manner. A capacity control can be set such that the capacity of a compressor only is allowed to start to decrease from a maximum capacity when a compressor suction pressure ps has dropped to a value of 2 atmospheres (absolute pressure) or less in a state in which refrigerant flows through a condenser without passing through a bypass line.

## Claims

### Claim 1

A vehicular refrigerating cycle comprising a compressor, a condenser for condensing refrigerant compressed by said compressor, an expansion valve, an evaporator for evaporating refrigerant adiabatically expanded by said expansion valve, a by-pass line detouring said condenser, a line switching means for supplying compressed refrigerant either to said condenser or into said by-pass line, and a capacity control means for variably controlling the capacity of said compressor corresponding to variations of its own suction pressure, said compressor being a variable capacity compressor the capacity of which automatically is decreasing with a reduction of its suction pressure, wherein said capacity control means is provided with setting means allowing the capacity of said compressor to begin to decrease from a maximum capacity first under a suction pressure of 2 atmospheres (absolute atmospheric pressure) or less in a state in which the refrigerant flows through the condenser without passing through said by-pass line.

### Claim 2 (depends on 1)

Vehicular refrigerating cycle as in claim 1, wherein said setting means allow the capacity of said compressor to begin to decrease from a maximum capacity first under a suction pressure of 1 atmosphere (absolute atmospheric pressure) or less in a state in which the refrigerant flows through said condenser without passing through said by-pass line.

### Claim 3 (depends on 1)

Vehicular refrigerating cycle as in claim 1, wherein said capacity control means comprises a solenoid, and an overcurrent supply to temporarily pass overcurrent through the solenoid prior to a state with refrigerant directed through the by-pass line without passing through said condenser, such that the capacity of the compressor starts to decrease from the maximum capacity first when a predetermined low value of said suction pressure or less has been reached.

### Claim 4 (depends on 1)

Vehicular refrigerating cycle as in claim 1, wherein said capacity control means are constituted by a solenoid actuated pressure regulating valve in a flow connection between a suction pressure line and a control pressure line, a value of a control pressure in said control pressure line determining the capacity of said variable capacity compressor between a maximum and a minimum, said valve controlling said flow connection between open and closed states in dependence from a relation between a valve closing force mainly depending on current supplied to said solenoid and an opening force generated by said suction pressure, and wherein said solenoid is connected to a current setting means for temporarily supplying an overcurrent to said solenoid for assuring said valve open state until said suction pressure has decreased to said value of about 2 atmospheres or less.

### Claim 5 (depends on 4)

Vehicular refrigerating cycle as in claim 4, wherein said current setting means is adapted to supply said overcurrent with a magnitude approximately double as high as a maximum magnitude of a continuous operation current for a long duration heating and/or cooling mode operation of said refrigerating cycle.

### Claim 6 (depends on 5)

Vehicular refrigerating cycle as in claim 5, wherein said over current is supplied for a short period of time immediately before refrigerant is allowed to pass through said by-pass line to reduce said suction pressure to a value of about 2.0 to 0.3 atmospheres, said short period of time amounting to about 30 seconds to about 1 minute.

### Claim 7 (depends on 5)

Refrigerating cycle as in claim 5, wherein the current setting means comprises a driving circuit connected to a control section including a control signal calculating CPU, said control section being connected to detection signal emitting sensors e.g. for engine operation conditions, temperatures inside and/or outside the vehicle, temperatures and/or pressures in the evaporator, etc.