WO2019015891A1

WO2019015891A1 - Refrigeration system of a vehicle having a refrigerant circuit

Info

Publication number: WO2019015891A1
Application number: PCT/EP2018/065830
Authority: WO
Inventors: Uwe Gerlinger; Peter Heyl; David Günther; Andreas ROEDER
Original assignee: Audi Ag; Hanon Systems
Priority date: 2017-07-20
Filing date: 2018-06-14
Publication date: 2019-01-24
Also published as: DE102017212479A1

Abstract

The invention relates to a refrigeration system (10) of a vehicle having a refrigerant circuit (1), and comprises a first refrigeration circuit (1.1) for air-conditioning the interior of the vehicle, comprising a refrigerant compressor (2), a condenser or gas cooler (3) and an air-conditioning evaporator (4) having an associated expansion member (4.1), a second refrigeration circuit (1.2) comprising a heat exchanger (5) having an associated expansion member (5.1) provided to be coupled to a heat source (5.0), and a refrigerant line section (1.0) connected upstream of the condenser or gas cooler for connecting the first refrigerant circuit (1.1) to the second refrigerant circuit (1.2), comprising a branching device (6), which is designed to branch off a first partial mass stream (m) of the refrigerant for the second refrigeration circuit (1.2) with a flow course following the refrigerant line section (1.0).

Description

The invention relates to a refrigeration system of a vehicle having a refrigerant circuit.

It is known to realize a refrigerant circuit for a vehicle air conditioner with a 2-evaporator system, namely with a front evaporator and a rear system evaporator. Electrified vehicles require in addition to the front evaporator (also called air conditioner evaporator) as at least one interior evaporator a separate heat exchanger for cooling a battery or other electronics. This heat exchanger can be configured as a chiller for a cooling water circuit or as a refrigerant-operated battery cooler (direct evaporator).

A vehicle air conditioning system is known from DE 198 39 477 A1, in which after a refrigerant condenser and a liquid collector, a first branch of the refrigerant circuit is provided, at which the refrigerant is branched into a first refrigerant flow and a second refrigerant flow. The first refrigerant flow flows via a first expansion element to an evaporator as a heat exchanger, while a second refrigerant flow via a second expansion element to an additional heat exchanger, which is heated by a HV (high-voltage) battery.

Such additional heat exchanger for a high-voltage battery are usually for reasons of optimal geometric and functional arrangement (Package) in the rear of the vehicle. The respective temperature-controlled expansion element is usually accommodated together with the evaporator or the additional heat exchanger or in direct proximity to the evaporator or the additional heat exchanger installed. The control of the refrigerant via the compressor speed of the refrigerant compressor via the outlet temperature of the air at the evaporator. This results in insufficient cooling capacity for cooling the high-voltage battery, especially at operating points with low cooling capacity of the air evaporator and high performance of the battery cooler in combination operation, since the air outlet temperature controls the performance of the compressor.

For the sake of completeness, reference should be made to DE 102 18 539 A1 and DE 10 2008 027 293 A1.

DE 102 18 539 A1 describes a device for cooling a battery pack for a vehicle having a source of cooling gas, a pump or a compressor for compressing the cooling gas and a high-pressure line system, which is in fluid communication with the pump and the compressed cooling gas feeds the battery pack, an expansion valve, which is in fluid communication with the high-pressure piping system and causes a decompression of the cooling gas and a low-pressure piping system, which is in fluid communication with the expansion valve comprises. By means of the low-pressure piping system, the cooling gas is passed through the entire battery pack and the same quickly cooled unevenly.

DE 10 2008 027 293 A1 relates to a device for cooling a vehicle battery, which comprises a plurality of electrical storage elements and a heat sink with channels for flowing through with a fluid body. The storage elements are in thermal contact with the heat sink, thereby transferring heat of the storage elements to the fluid. It is an object of the invention to provide a refrigeration system of a vehicle with a refrigerant circuit, which has a first refrigerant circuit for the interior air conditioning of the vehicle and a second refrigerant circuit with a has provided for coupling with a heat source heat exchanger with associated expansion element and compared to the prior art, an increased cooling capacity for the heat exchanger for cooling the heat source, eg. Provides a high-voltage battery.

This object is achieved by a refrigeration system having the features of patent claim 1.

Such a refrigeration system of a vehicle with a refrigerant circuit comprises:

a first refrigerant circuit for the interior air conditioning of the vehicle with a refrigerant compressor, a condenser or gas cooler and an evaporator with an associated expansion element,

- A second refrigerant circuit with a provided for coupling to a heat source heat exchanger with associated expansion element, and

- A downstream of the condenser or gas cooler refrigerant line section for connecting the first refrigerant circuit to the second refrigerant circuit with a branching device, which is designed to divert a first partial mass flow of the refrigerant for the second refrigerant circuit with a flow path following the refrigerant pipe section.

In addition, this refrigeration system can have an internal heat exchanger and a refrigerant collector.

With such a branching device according to the invention, a connection geometry is created with which the course of the refrigerant in favor of the second cooling circuit is preferred, so that a sufficient mass flow is available for cooling the heat source. This connecting geometry according to the invention realized by the branching device consists in the fact that the flow profile predetermined by the refrigerant line section is maintained for the first partial mass flow and thus no deflection takes place from the predetermined direction of the refrigerant pipe section. This reduces the flow resistance of the first partial mass flow with the consequence of the preference of the refrigerant flow in favor of the heat exchanger provided for cooling the heat source.

A further advantage is that evaporator-controlled regulation of the refrigerant compressor can also be realized for the refrigeration system according to the invention, which is particularly relevant for hybrid vehicles or electric vehicles.

According to an advantageous development of the invention, the branching device is designed to divert a second partial mass flow from the refrigerant for the air-conditioning evaporator by deflecting it from the direction of the refrigerant line section. In this second partial mass flow of the refrigerant thus generated, there is an increased flow resistance in comparison to the first partial mass flow, so that the flow course of the refrigerant in the direction of the second refrigerant circuit is also preferred therewith.

It is particularly advantageous if, in accordance with further development, the coolant conduit section has a straight or curved course. Thus, the flow path of the refrigerant in the direction of the second cooling circuit is not substantially hindered.

Furthermore, an advantageous embodiment of the invention provides that the branching device is designed as a 3-Wegeverbindungsanordung. Preferably, the branching means comprises an inlet portion and an outlet portion aligned with the same, and a branch portion not aligned with the inlet and outlet portions. According to a further embodiment of the invention, pressure loss optimization is achieved by providing a return line of the heat exchanger between its exit and a connection point between the air conditioning evaporator and the cold compressor having at least the same cross section or a larger cross section compared to the cross section the line sections of the evaporator branch is formed between the branching device and the connection point.

A particularly advantageous embodiment of the invention provides that in a caused by the prioritization of the refrigerant pipe section refrigerant deficit in the air-evaporator in dependence of a temperature detected by a temperature sensor, the power of the refrigerant compressor is increased regardless of the state of the heat exchanger.

According to a last advantageous embodiment of the invention, the return lines of the air-conditioner evaporator and the heat exchanger on the same pressure losses, this is further education achieved in that at least one same cross-section is used. A detailed Ab- tuning can be done over the respective length of the line sections after the evaporators to the connector and the expected mass flow of the refrigerant. The goal, however, is that the pressure loss in both lines is of the same order of magnitude in order to be able to realize the same evaporation temperature at the evaporator outlet of both heat exchangers.

The invention will now be described in detail by means of an embodiment with reference to the accompanying figures. Show it:

Figure 1 is a circuit diagram of an embodiment of the invention

Refrigeration system, and FIG. 2 shows a detailed perspective view I of a line branching of the refrigeration system according to FIG. 1 between the air conditioning compressor and the heat exchanger provided for cooling the heat source.

The refrigeration system 10 of a vehicle according to FIG. 1 consists of a refrigerant circuit 1 with a first refrigeration circuit 1 .1 and a second refrigeration circuit 1 .2.

The first refrigeration circuit 1 .1 is used for the interior air conditioning of the vehicle and comprises a refrigerant compressor 2, a condenser or gas cooler 3, a refrigerant collector 7 and a climate evaporator 4 with upstream expansion element 4.1, wherein this component flows through in the listed order of a refrigerant become. In the refrigeration operation of the refrigeration system 10, a supply air flow L2 supplied to the vehicle interior is dehumidified and / or cooled by means of the climate evaporator 4 and the heat absorbed thereby is removed via the condenser or gas cooler 3 to an ambient air flow L1.

The air-conditioning evaporator 4 is located together with its expansion element 4.1 in an evaporator branch 4.0 extending between a branching device 6 and a branching point P, wherein the refrigerant flow through the air-conditioning evaporator 4 can be switched off by means of a shut-off valve 4.2 arranged in this evaporator branch 4.0.

With a pressure sensor 8, the pressure of the refrigerant at the inlet of the condenser or gas cooler 3 is detected. A temperature sensor 9 in the region of the supply air flow L2 serves for detecting the air temperature at the outlet of the air-conditioning evaporator 4. The air-conditioning evaporator 4 is optionally arranged with further components in an air conditioning unit of the vehicle. In a combined operation, a second refrigeration circuit 1 .2 is connected to the first refrigeration circuit 1 .1 in order to cool a heat source 5.0 by means of a heat exchanger 5 arranged in the second refrigeration circuit 1 .2. This heat source 5.0 represents, for example, a high-voltage battery (HV battery) with which, for example, an electric drive machine of a hybrid vehicle or a pure electric vehicle is driven. A power electronics to be cooled or other electrical component of the vehicle to be cooled also represents such a heat source 5.0. This second refrigeration circuit 1 .2 consists of a feed line 1 .21, which the branching device 6 via a shut-off 5.2 with an inlet E of the heat exchanger. 5 connects with its associated expansion element 5.1. A return line 1 .20 of the second refrigerant circuit 1 .2 connects an outlet A of the heat exchanger 5 with the connection point P.

The branching device 6 is arranged in a line section 1 .0 of the refrigerant circuit 1, which is supplied via a connected to the condenser or gas cooler 3 and the refrigerant collector 7 line section 1 .10 a mass flow mo as the total mass flow of the refrigerant. From this mass flow mo is by means of the branching device 6 on the one hand, a partial mass flow in which is expanded via the feed line 1 .21 with opened shut-off valve 5.2 by means of the expansion element 5.1 in the heat exchanger 5, and on the other hand, a second partial mass flow nri2, which at open shut-off valve 4.2 is relaxed by means of the expansion element 4.1 in the air-conditioner evaporator 4, branched off.

In this case, the branching device 6 is set up such that the flow profile of the first partial mass flow mi follows the course of the refrigerant line section 1 .0, as will be explained in more detail below with reference to the detail I according to FIG. This figure 2 shows the refrigerant line section 1 .0 with the branching device 6, to which the evaporator branch 4.0 is connected. The branching device 6 connects a line section 1 .100 of the connecting line 1 .10 with a line section 1 .210 of the inlet line 1 .21 of the heat exchanger 5.

The branching device 6 consists of an inlet section 6.1, an outlet section 6.2 and a branch section 6.3. In this case, the inlet and outlet sections 6.1 and 6.2 are oriented in alignment with one another such that the first partial mass flow branched off from the mass flow mo follows in the course of the two line sections 1 .100 and 1 .210. This leads to a continuous flow path or flow path of the first partial mass flow m1 from the connecting line 1 .10 into the feed line 1 .21. If the two line sections 1 .100 and 1 .210 run in a straight line, this also leads to a straight-line flow path or flow path. If the two line sections 1 .100 and 1 .210 form an arcuate course, the flow path or flow path of the first partial mass flow mi is also adapted to this continuous arcuate course.

The first partial mass flow nm is therefore not deflected by the branching device 6 from the course predetermined by the direction of the two line sections 1 .100 and 1 .210. In contrast, the second partial mass flow nri2 is deflected from this predetermined flow direction by means of the branching device 6. For this purpose, this branching device 6 is designed such that according to Figure 2, the second partial mass flow nri2 is diverted by a two-fold 90 ° deflection from the mass flow mo and flows into the evaporator branch 4.0. With this branching geometry in the area of the refrigerant line section 1 .0, the course of the refrigerant into the feed line 1 .21 in favor of the heat exchanger 5 is preferred, ie prioritized, with the result that at otherwise identical operating conditions a larger first partial mass flow mi flows into the heat exchanger 5, as in the opposite case, when the outlet section 6.2 with the evaporator branch 4.0 and the branch section 6.3 with the feed line 1 .21 of the heat exchanger 5 would be fluidly connected.

Furthermore, with this branching geometry in the area of the refrigerant line section 1 .0, the pressure loss ratios between the first refrigerant circuit 1 .1 and the second refrigeration circuit 1 .2 are adjusted, as a result, similar pressures are present on the suction side of the refrigerant compressor 2, which at the same evaporation pressures and thus also the same Evaporation temperatures at the air conditioning evaporator 4 and the heat exchanger 5 lead. If too little mass flow mo is supplied by the refrigerant compressor 2, control via the evaporator outlet temperature causes the compressor speed to be increased and thus more refrigerant to be circulated. This means that when the refrigerant deficit in the air-conditioning evaporator 4 caused by the prioritization of the refrigerant line section 1 .0 (ie, prioritization of the refrigerant flow into the feed line 1 .21) is independent of the temperature value detected by the temperature sensor 9, the power of the refrigerant compressor 2 is independent is increased by the state of the heat exchanger 5, d. H. the control are no information of the heat exchanger 5 before.

Not only is more refrigerant in the air-conditioning evaporator 4 available, but at the same time the heat exchanger 5 also receives more refrigerant. In the case of a low outside temperature, ie if the cooling power for the vehicle interior is low, the branching geometry according to the invention in the region of the refrigerant line section 1 .0 becomes due to the prioritization of the refrigerant flow in the feed line achieved. tion 1 .21 sufficient refrigerant to the heat exchanger 5 for cooling the heat source 5.0 provided.

If the expansion element 4.1 of the air-conditioner evaporator 4 is designed as a thermal expansion valve (TXV) or an electrical expansion element (EXV), this is opened at an increased overheating.

Since the heat exchanger 5 is usually in the rear of the vehicle, the return line 1 .20 of the heat exchanger 5 is adapted to the line cross sections of the evaporator branch 4.0 to further optimize the pressure losses in the first and second refrigerant circuits 1 .1 and 1 .2 by the line cross-section of the return line 1 .20 at least equal to or greater than that of the evaporator branch 4.0 is selected, whereby its flow resistance despite the long connecting lines in the rear carriage reduced and thereby the prioritization of the refrigerant flow in the second refrigerant circuit 1 .2 still reinforced and thereby an improved cooling capacity of the heat exchanger 5 is achieved. In a design with the same cross-section, oil return problems can be avoided.

It is also provided to carry out the return line of the air-conditioner evaporator 4 and the return line 1 .20 of the heat exchanger 5 so that there are equal pressure losses, this is achieved in that at least one same cross-section is used. A detailed vote can be made on the length of each line sections after the evaporators to the connector and the expected mass flow of the refrigerant. The goal, however, is that the pressure loss in both lines is of the same order of magnitude in order to be able to realize the same evaporation temperature at the evaporator outlet of both heat exchangers. reference numeral

1 refrigeration circuit

1 .0 refrigerant pipe section of the refrigerant circuit 1

1 .1 first refrigeration cycle

1 .10 Connecting line of the first refrigeration cycle 1 .1

1 .100 line section of the connecting line 1 .10 1 .2 second refrigeration circuit

1 .20 Return line of the heat exchanger 5

1 .21 Supply line of the heat exchanger 5

1 .210 Line section of supply line 1 .21 2 Refrigerant compressor

3 condenser or gas cooler

4 climate evaporator

4.0 evaporator branch

4.1 Expander of the Climate Evaporator 4

4.2 shut-off valve

5 heat exchangers

5.0 heat source

5.1 expansion element of the heat exchanger 5

5.2 shut-off valve

6 branching device

6.1 inlet section of the branching device 6 6.2 outlet section of the branching device 6

6.3 Branching section of the supply device 6 7 Refrigerant collectors

8 pressure sensor

9 Temperature sensor 10 Refrigeration system

L1 airflow

L2 supply air flow mo mass flow of the refrigerant

mi first partial mass flow of the mass flow mo ni2 second partial mass flow of the mass flow mo

P connection point

Claims

claims

Refrigeration system (10) of a vehicle having a refrigerant circuit (1) comprising

- A first refrigerant circuit (1 .1) for the interior air conditioning of the vehicle with a refrigerant compressor (2), a condenser or gas cooler (3) and a climate evaporator (4) with associated expansion element (4.1),

- A second refrigerant circuit (1 .2) with a provided for coupling to a heat source (5.0) heat exchanger (5) with associated expansion element (5.1), and

- A downstream of the condenser or gas cooler (3) refrigerant line section (1 .0) for connecting the first refrigerant circuit (1 .1) with the second refrigerant circuit (1 .2) with a branching device (6) which is formed a first partial mass flow ( mi) from the refrigerant for the second refrigerant circuit (1 .2) with a the refrigerant line section (1 .0) following branch flow.

Refrigeration plant (10) according to claim 1, wherein the branching device (6) is adapted to branch off a second partial mass flow (nri2) from the refrigerant for the air-conditioning evaporator (4) by deflecting from the direction of the coolant line section (1 .0).

Refrigeration system (10) according to claim 1 or 2, wherein the refrigerant line section (1 .0) has a straight or curved course. 4. refrigeration system (10) according to any one of the preceding claims, wherein the branching device (6) is formed as a 3-Wegeverbindungs- arrangement. Refrigeration system (10) according to claim 4, wherein the branching device (6) has an inlet section (6.1) and an aligned with the outlet section (6.2) and with the inlet and outlet section (6.1, 6.2) branching section (6.3).

Refrigeration system (10) according to any one of the preceding claims, wherein a return line (1 .20) of the heat exchanger (5) between the outlet (A) and between the air conditioning evaporator (4) and the refrigerant compressor (2) lying connection point (P ) is formed with a larger cross section compared to the cross section of the line sections of the evaporator branch (4.0) between the branching device (6) and the connection point (P).

Refrigeration plant (10) according to one of the preceding claims, in which a refrigerant deficit caused by the prioritization of the refrigerant line section (1 .0) in the air-conditioning evaporator (4) as a function of a temperature value detected by means of a temperature sensor (9) determines the capacity of the refrigerant compressor (2). regardless of the state of the heat exchanger (5) is increased.