# US 2014/0150476 A1 · Refrigerant Circuit And Method Of Controlling Such A Circuit

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- Number: US 2014/0150476 A1
- Document ID: US20140150476A1
- Status: Published application
- Kind: A1
- Application number: 14/126,231
- Filed: 2012-04-25
- Published: 2014-06-05
- Earliest claimed: 2011-06-16
- Assignees: Valeo Systemes Thermiques
- Inventors: Jin-Ming Liu
- Web page: https://patentgrep.com/patent/US20140150476A1

## CPC

- F25B 29/003: {of the compression type system}
- B60H 1/00392: {for electric vehicles having only electric drive means}
- B60H 1/00785: {by the detection of humidity or frost}
- B60H 1/00914: {where the flow direction of the refrigerant does not change and there is a bypass of the condenser}
- F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES

## Abstract

The invention relates to a refrigerant circuit (1) for thermally conditioning a vehicle passenger compartment, comprising a plurality of branches containing at least one exchanger, of which branch a first branch (11) is in series with a second branch (12) and a third branch (13), said second branch (12) being in parallel with said third branch (13), and a means (36) of placing the third branch (13) in communication with the second branch (12), said means being installed between a sector (37) of the third branch (13) which sector is situated downstream of an external exchanger (28) and a portion (38) of the second branch (12) which is situated upstream of a first control member (15).

## Claims

### Claim 1

A refrigerant fluid circuit for thermally conditioning a cabin of a vehicle, comprising:
a first branch in which are installed in series at least one compressor and an interior exchanger designed to ensure thermal exchange between the refrigerant fluid and an interior air stream, to be dispatched into the cabin,
a second branch in which are installed in series at least one first means of control of the circulation of the refrigerant fluid in said second branch, a first expansion member and an evaporator,
a third branch in which are installed in series at least one second expansion member and an exterior exchanger designed to ensure thermal exchange between the refrigerant fluid and an exterior air stream, arranged outside the cabin,
said first branch being in series with the second branch and the third branch, said second branch being in parallel with said third branch,
a means for placing the third branch in communication with the second branch, said means being installed between a sector of the third branch situated downstream of the exterior exchanger and a portion of the second branch situated upstream of the first expansion member.

### Claim 2 (depends on 1)

The circuit as claimed in claim 1, in which the means for placing in communication is formed by at least one member for managing the circulation of the refrigerant fluid in the sector or in a conduit installed between the sector and the portion of the second branch.

### Claim 3 (depends on 2)

The circuit as claimed in claim 2, in which the conduit is hooked up to the second branch between the first means of control and the first expansion member.

### Claim 4 (depends on 1)

The circuit as claimed in claim 1, in which the third branch comprises a second means for controlling the circulation of refrigerant fluid in said third branch.

### Claim 5 (depends on 4)

The circuit as claimed in claim 4, in which the second control means is installed upstream of the second expansion member.

### Claim 6 (depends on 1)

The circuit as claimed in claim 1, in which the third branch comprises a bypass valve of the second expansion member.

### Claim 7 (depends on 1)

The circuit as claimed in claim 1, designed to operate according to a mode of heating where a quantity of heat absorbed by the exterior exchanger is dissipated in the interior air stream by the interior exchanger, according to a mode of cooling where a quantity of heat absorbed by the interior exchanger is dissipated in the exterior air stream by the exterior exchanger, and according to at least three modes of dehumidification which combine the mode of heating and the mode of cooling, and in which a refrigerant fluid circulates in the same direction independent of the mode.

### Claim 8 (depends on 7)

The circuit as claimed in claim 7, comprising means which, in modes of dehumidification, are designed to:
impose a circulation of refrigerant fluid in the first branch and in the third branch,
impose a circulation of refrigerant fluid in the first branch, in the third branch, in the means for placing the third branch in communication with the second branch, and in the second branch,
impose a circulation of refrigerant fluid in the first branch and in the second branch,
impose a circulation of refrigerant fluid in the first branch and simultaneously in the second and the third branch.

### Claim 9 (depends on 1)

A method of controlling a thermal system for conditioning an interior air stream dispatched into a cabin of a vehicle comprising a circuit as claimed in claim 1 and a housing in which said interior air stream circulates, and containing the interior exchanger, the evaporator, in which:
a) the circuit is activated,
b) the presence of ice on the exterior exchanger is determined,
c) in the presence of ice,
a circulation of refrigerant fluid is imposed in the first branch, in the third branch, in the means for placing the third branch in communication with the second branch, and in the second branch,
d) in the absence of ice, the temperature of the interior air stream is determined,
e) if the temperature of the interior air stream is above a threshold temperature, a circulation of refrigerant fluid is imposed in the first branch and in the second branch,
f) if a power delivered by the circuit is less than a low power threshold, a circulation of refrigerant fluid is imposed in the first branch and simultaneously in the second and the third branch,
g) if the temperature of the interior air stream is below the threshold temperature, a circulation of refrigerant fluid is imposed in the first branch and in the third branch.

### Claim 10 (depends on 9)

The method as claimed in claim 9, where the housing comprises an air inlet device controlling the quantity of air outside the cabin and/or the quantity originating from the cabin admitted into the housing, in which:
in the presence of ice, the air inlet device is positioned so that the air admitted into the housing consists of at least 80% of air originating from the cabin;
if the power delivered by the circuit is above a high power threshold, the air inlet device is positioned so that the air admitted into the housing consists predominantly of air originating from outside the cabin;
if the power delivered by the circuit is less than the low power threshold, the air inlet device is positioned so that the air admitted into the housing consists wholly of air originating from the cabin;
if the temperature of the interior air stream is below the threshold temperature, the air inlet device is positioned so that the air admitted into the housing consists wholly of air originating from the cabin.

### Claim 11 (depends on 10)

The method as claimed in claim 10, in the course of which the air inlet device is positioned as a function of an item of information regarding quality of the interior air stream.

### Claim 12 (depends on 10)

The method as claimed in claim 10, comprising a step of comparing the positions of the air inlet device and a step where the position where the quantity of exterior air is the most significant is imposed.

### Claim 13 (depends on 2)

The circuit as claimed in claim 2, in which the third branch comprises a second means for controlling the circulation of refrigerant fluid in said third branch.

### Claim 14 (depends on 3)

The circuit as claimed in claim 3, in which the third branch comprises a second means for controlling the circulation of refrigerant fluid in said third branch.