Compressor arrangement and thermal management system with compressor arrangement

Abstract

Compressor arrangement (30) for the thermal management system of a vehicle comprising a single electric motor (32) with two parallel or coaxially arranged shafts (37) connected to two compressors (33a, 33b), wherein the two compressors (33a, 33b) can be controlled individually or in series or in parallel.

Description

[0001] The invention relates to a compressor arrangement for the thermal management system of a vehicle consisting of a single electric motor with two parallel or coaxially arranged shafts connected to two compressors, wherein the two compressors can be controlled individually or in series or in parallel. State of the art

[0002] The thermal systems of electric vehicles often consist of a heat pump system. However, at temperatures below zero degrees Celsius, the ambient temperature is no longer sufficient to evaporate the refrigerant in the air conditioning circuit. Therefore, external heat sources such as an electric heater are necessary to heat the system when stationary or while driving.

[0003] From WO 2022 / 258 311 A1, an exemplary heat pump arrangement for a hybrid or electric vehicle is known, comprising a refrigerant circuit with a flow path for a refrigerant, a compressor, a high-pressure refrigerant heat exchanger integrated into a high-temperature latent heat storage device, an expansion element and a low-pressure refrigerant heat exchanger integrated into a low-temperature latent heat storage device.

[0004] According to the current state of the art, it is very difficult to achieve high efficiency and simultaneously deliver high cooling and heating performances for the most common operating points, which are usually in the lower power range, when dimensioning compressors and heat pumps for automotive applications.

[0005] There are technologies that can achieve the required high performance, but do not operate efficiently in the lower performance range.

[0006] This disadvantage must be overcome, and a system must be dimensioned to achieve the high performance levels while efficiently meeting the low-power requirements. This is very difficult to achieve with a single compressor, as it must be designed for a specific, narrow efficiency range.

[0007] A single compressor can either be sized to be frequently efficient in low-power areas, in which case it can be very difficult to deliver high power. Or the compressor can be sized to easily deliver high power, resulting in lower efficiencies in low-power areas. The characteristic operating range of a single compressor is not suitable for the wide variety of applications and requirements that exist for heat pump applications in automotive vehicles.

[0008] US 2005 257 545 A1 discloses an HVAC (Heating, Ventilation, and Air Conditioning) system having a predetermined cooling capacity and comprising a condenser, a baffle tube, and an expansion valve in fluid communication with the condenser. A first compressor may be mechanically driven by the engine and is in fluid communication with the evaporator and the condenser. A second compressor is electrically connected to and driven by the battery bank. It is in fluid communication with the evaporator and the condenser. Each of the compressors is selectively operable to compress refrigerant in the HVAC system during operation of the HVAC system.The first and second compressors may be in fluid communication with the condenser in a parallel configuration, wherein the first compressor and the second compressor each have their own suction line in fluid communication with the evaporator.

[0009] In the parallel configuration, the first and second compressors flow into a common outlet line that is in fluid communication with the condenser.

[0010] Alternatively, the first and second compressors can be fluidly connected to the condenser in a series configuration, with the first compressor connecting to the intake duct of the second compressor and the second compressor connecting to the condenser. Regardless of the series or parallel configuration, each compressor can be operated independently.

[0011] The object of the invention is to create an HVAC system which is adaptable for the individual operating points of such a system. Description of the invention

[0012] The problem is solved with a compressor arrangement in the vehicle having the features of claim 1.

[0013] The problem is solved with a compressor arrangement for the thermal management system of a vehicle consisting of a single electric motor with two parallel or coaxially arranged shafts or a continuous shaft connected to two compressors, whereby the two compressors can be controlled individually or in series or in parallel.

[0014] The use of a through shaft results in a simple implementation of the electric motor cable.

[0015] However, if different compressors are used at the shaft ends, it is better to have separate shafts and also to allow for an axial offset for the potential installation of a gearbox.

[0016] The advantage is that one compressor is connected to a 3-way valve on the inlet side and the other compressor is connected to a 3-way valve on the outlet side.

[0017] On the output side, both compressors are connected to the output via a check valve.

[0018] There can be the same or different compressor types or even different / same compressor sizes, e.g. two scroll compressors, but one with 4kW and one with 6kW.

[0019] It is advantageous if scroll compressors or rotary piston compressors are used.

[0020] The task is also solved with a thermal management system with a compressor arrangement, whereby the compressor arrangement is installed in a heat pump.

[0021] The thermal management system includes at least the following components: An electric drive train, A battery, A passenger compartment, A radiator.

[0022] The proposed solution overcomes the problem of the narrow operating range of a single compressor compared to the wide range of applications to be covered. The proposed solution consists of two compressors dimensioned at lower power to achieve the defined system power, rather than a single compressor directly designed for a defined system power.

[0023] This enables the following advantages to be achieved over a single high-performance compressor system.

[0024] Increased operating range coverage by operating both compressors in series / parallel configuration, allowing high performance requirements to be met. Higher efficiency by using a single compressor for applications with low performance requirements. Description of the characters Fig. 1 shows a compressor arrangement according to the invention, Fig. 2 to 4 show different operating states, Fig. 5 shows a heat pump arrangement from the prior art.

[0025] Fig. Figure 5 shows the integration of a heat pump arrangement 1 into a thermal management system of an electric vehicle in one example. A high-pressure refrigerant heat exchanger can be coupled to a cooling circuit or a heating circuit of the vehicle via a high-temperature heat exchanger and a high-temperature coolant heat exchanger and a low-pressure refrigerant heat exchanger, depending on the operating mode. The two heat exchangers are connected via a compressor 30 and an expansion valve 31 and form a heat pump system 1.

[0026] A high pressure side 14 of the heat pump arrangement 1 provides warm coolant and a low pressure side 15 of the heat pump arrangement 1 provides cold coolant.

[0027] The following components and assemblies must be thermally conditioned on the vehicle side: An electric drive train 17 (engine, power electronics, charger and, depending on the application, also transmission) generates waste heat during operation, which must be dissipated by the thermal management system or can be used for preconditioning.

[0028] A battery 18 generates waste heat during operation and charging, which must also be compensated for by suitable cooling. However, the battery can also be heated by the thermal management system, for example, during cold start conditions in winter.

[0029] A passenger compartment 23 is supplied with warm or cold air, which is blown into the interior of the passenger compartment via outlet nozzles. The necessary cooling or heating power is achieved via a heat exchanger 20, which can be supplied with hot or cold coolant as required. Air flows through a radiator 21 in the front section of the vehicle, dissipating excess heat from the thermal management system to the environment.

[0030] Two pumps 22a, 22b ensure the coolant mass flow required for operation via valves V1 to V6.

[0031] An additional air-side electric heater 19 can be installed and is used in the dehumidification mode of the air conditioning system to heat the air, which has only been cooled in the heat exchanger 20 (in order to achieve condensation of the air humidity), back to the desired inflow temperature in the passenger compartment 23.

[0032] In principle, the electric drive train 17 functions as a parking heater, heating the surrounding coolant using the waste heat from the inverters and electric motors installed in the vehicle. The heat thus generated is used to evaporate refrigerant in a heat pump system 1. Preconditioning can be active both when the vehicle is stationary and while driving, i.e., during recuperation, sailing, coasting, and driving forward and backward. Generating additional waste heat while driving is state-of-the-art by selecting the most inefficient operating point possible for both the inverter and the electric motor.

[0033] The waste heat generated via the electric drive train 17 is fed into the high-pressure side of the heat pump arrangement and serves to heat the vehicle.

[0034] Fig. 1 shows a switchable dual compressor device 30 driven by a single electric motor 32.

[0035] The electric motor 32 drives two shafts 37 which are arranged coaxially or parallel to each other on the electric motor 32.

[0036] Two compressors 33a and 33b are driven by the shafts. These compressors 33a and 33b can be identical in construction, have different designs, or be different compressor types.

[0037] Scroll compressors are shown as an example.

[0038] A scroll compressor consists of two intermeshing spirals 35, 36. While one spiral 36 is fixed, the other spiral 35 moves eccentrically in circles via the eccentrics 34a, 34b. This creates several gas spaces between the spirals, which become progressively smaller toward the interior of the component.

[0039] The electric motor 32 allows the operation of a single compressor see Fig. 2 for low load operating points and both compressors simultaneously for high load operating points see Fig. 3 and Fig. 4. Depending on the load operating points, the compressors are either in series, see Fig. 3, or parallel to each other, see Fig. 4 to best meet the requirements of the operating point.

[0040] The compressor arrangement 30 enables the operation of a single compressor with lower total power for low load operating points and is thus more efficient compared to the operation of a compressor with higher power for low loads by improving the efficiency.

[0041] The compressor arrangement 30 enables a series or parallel architecture of both compressors, thus expanding the operating range in terms of mass flow. For this purpose, one inlet 40 of compressor 33b is connected via a three-way valve 42, while the other inlet of the other compressor 33a is connected directly to inlet 40. Both outlets lead to outlet 41. Compressor 33a, which is directly connected to inlet 40, is connected to outlet 41 via another three-way valve 43.

[0042] On the output side, both outlets of the compressors are also provided with a check valve 44.

[0043] This makes it possible to adjust the operating point to a certain extent in order to achieve maximum efficiency by switching between single or double compressor.

[0044] It is possible to actively switch between series or parallel connection, which enables the system to dynamically achieve a high pressure ratio or a high mass flow rate depending on the requirements.

[0045] In parallel operation of the Fig. 3, the inlet 40 is connected to both compressors 33a and 33b via the 3-way valve 42. The compressor 33a is then connected to the inlet of the compressor 33b via the 3-way valve 43 and the 3-way valve 42. On the output side, only the compressor 33b is connected to the outlet 41.

[0046] In serial operation of the Fig. 4, the flow is directed via the inlet 40 directly into the compressor 33a.

[0047] Compressor arrangement 30 has the capability of providing a medium temperature and pressure level when using the series configuration and the ability to expand the efficiency band by having both compressors operate at maximum efficiency bands in different ranges. The minimum possible mass flow is reduced. Furthermore, redundancy is incorporated, since if one compressor fails, the other can take over at least part of the load.

[0048] An alternative design uses rotary piston compressors driven by a single electric motor. A rotary piston compressor is a compressor in which the piston rotates completely. The refrigerant is compressed in a closed cylinder, against whose inner wall an eccentrically mounted circular cylinder rolls. The suction and discharge sides are separated by slide valves in the cylinder, eliminating the need for valves. Reference symbol 1 heat pump system 14 High pressure side 10 Drivetrain 17 Electric drivetrain 18 Battery 19 additional heaters 20 heat exchangers 21 Radiator 22 a, 92 b pumps 23 Passenger compartment 30 Compressor arrangement 31 Expansion valve 32 electric motor 33 a, 33 b compressor 34 a, 34 b eccentric 35 movable spiral 36 stuck spiral 37 Wave 40 Entrance 41 Exit 42,43 3-way valve V1...V6 valves QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2005 257 545 A1

[0008]

Claims

[1] Compressor arrangement (30) for the thermal management system of a vehicle consisting of a single electric motor (32) with two parallel or coaxially arranged shafts or a continuous shaft (37) connected to two compressors (33a, 33b), wherein the two compressors (33a, 33b) can be controlled individually or in series or in parallel. [2] Compressor arrangement (30) according to claim 1, characterized by that one compressor (33b) is connected on the inlet side to a 3-way valve (42) and the other compressor (33a) is connected on the outlet side to a 3-way valve (43). [3] Compressor arrangement (30) according to claim 1 or 2, characterized by that on the output side both compressors (33a, 33b) are connected to the output (41) via a check valve. [4] Compressor arrangement (30) according to one of the preceding claims, characterized by that the same or different compressor types or sizes are used. [5] Compressor arrangement (30) according to one of the preceding claims, characterized by that scroll compressors or rotary piston compressors are used. [6] Thermal management system with a compressor arrangement according to one of claims 1-5, wherein the compressor arrangement (30) is installed in a heat pump. [7] Thermal management system according to claim 6, characterized by that the thermal management system has at least the following components: An electric drive train (17), A battery (18), A passenger compartment (23), A radiator (21).

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