System and method for refrigerant management in an electric vehicle
11479082 · 2022-10-25
Assignee
Inventors
- Chris Chatham (Coventry, GB)
- Dhillip Asokan (Coventry, GB)
- Kate Rouse (Coventry, GB)
- Oliver Stocks (Coventry, GB)
- Gael Chouchelamane (Coventry, GB)
- Richard Cook (Coventry, GB)
Cpc classification
B60H2001/00307
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/00928
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/3252
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/3258
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00392
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00907
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00778
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/325
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00007
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/3263
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00978
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/3257
PERFORMING OPERATIONS; TRANSPORTING
B60H2001/00949
PERFORMING OPERATIONS; TRANSPORTING
B60H1/322
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00492
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00921
PERFORMING OPERATIONS; TRANSPORTING
B60H1/00385
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A refrigerant management system in a heat flux management system for an electric vehicle and a method of refrigerant management is provided. The system includes a vehicle air conditioning circuit including a heat pump circuit and a refrigeration cycle refrigerant circuit, the air conditioning circuit including a heat pump condenser in thermal communication with a heat source, a refrigerant evaporator in thermal communication with the heat source, an evaporator associated with an expansion valve, and a refrigerant compressor where the components are fluidly connected to one another by a refrigerant line. An accumulator is fluidly coupled in the refrigerant line downstream of the heat pump condenser, the refrigerant evaporator and evaporator and upstream of the refrigerant compressor, and the air conditioning circuit is switchable between a heating mode and a cooling mode in which the refrigerant circuit is in fluid communication with the compressor by actuation of at least one valve.
Claims
1. A refrigerant management system in a heat flux management system for an electric vehicle, the refrigerant management system comprising a vehicle air conditioning circuit comprising a heat pump circuit with a heating function and a refrigeration cycle refrigerant circuit, the air conditioning circuit comprising a heat pump condenser in thermal communication with a heat source, a refrigerant evaporator in thermal communication with the heat source, an evaporator associated with an expansion valve, and a refrigerant compressor, wherein the components are fluidly connected to one another by a refrigerant line, an accumulator fluidly coupled in the refrigerant line downstream of the heat pump condenser, the refrigerant evaporator and evaporator and upstream of the refrigerant compressor, the heat pump circuit comprising an indirect condenser downstream of the refrigerant compressor and in thermal communication with a heat sink and the refrigerant evaporator and the evaporator in fluid communication with the refrigerant compressor and the indirect condenser; the refrigeration cycle refrigerant circuit comprising the heat pump condenser in fluid communication with the compressor; wherein the air conditioning circuit is switchable between a heating mode in which the heat pump circuit is in fluid communication with the compressor and the heat pump condenser is isolated from fluid communication with the compressor and a cooling mode wherein the refrigerant circuit is in fluid communication with the compressor by actuation of at least one valve; wherein the air conditioning circuit comprises a sensor at the compressor inlet operable to monitor refrigerant temperature and pressure; and wherein when the system is in the heating mode, a shut off valve in line between the heat pump condenser and the accumulator is operable to open to initiate a cold start mode in which a temporary fluid communication is provided between the heat pump condenser and the accumulator in the heat pump circuit when: the sensor detects one or both of: a superheated refrigerant at the compressor inlet and a temperature gradient of more than 3 Kelvin between the ambient temperature and the temperature at the compressor inlet.
2. The refrigerant management system according to claim 1, wherein each of the heat pump condenser, the refrigerant evaporator and the evaporator are each associated with at least one valve.
3. The refrigerant management system according to claim 1, wherein the compressor is associated with at least one valve.
4. The refrigerant management system according to claim 3, wherein the at least one valve is associated with the outlet of the compressor and is operable to switch the outlet of the compressor into fluid communication with the heat pump circuit or the refrigeration cycle refrigerant circuit in the heating mode or the cooling mode respectively.
5. The refrigerant management system according to claim 4, wherein the at least one valve associated with the compressor and at least one valve associated with the heat pump condenser are operable to switch the system from the heating mode to the cooling mode.
6. The refrigerant management system according to claim 1, wherein in the heating mode the heat pump condenser is fluidly isolated from the compressor by actuation of at least two valves.
7. The refrigerant management system according to claim 6, wherein in the heating mode the heat pump condenser is fluidly isolated from the compressor by closure of at least two valves one valve associated with the inlet and one valve associated with the outlet of the heat pump condenser.
8. The refrigerant management system according to claim 1, wherein in the heating mode, the heat pump condenser is fluidly isolated from the inlet and the outlet of the compressor and/or the heat pump condenser is fluidly isolated from the refrigerant evaporator, the evaporator, and the refrigerant compressor, and/or the heat pump condenser is isolated from the outlet of the compressor by closing a shut off valve and from refrigerant evaporator and the evaporator by closing an associated expansion valve and from the accumulator by closing the shut off valve, and/or the heat pump condenser is isolated from the heat pump circuit by closing at least one valve at the outlet of the compressor.
9. The refrigerant management system according to claim 1, wherein in the cooling mode, the heat pump condenser is in fluid communication with the compressor, and/or the heat pump condenser is in fluid communication with the outlet of the compressor, the accumulator and with the refrigerant evaporator by actuation of a plurality of associated valves.
10. The refrigerant management system according to claim 1, wherein the shut off valve in line between the heat pump condenser and the accumulator is closed in the cold start mode when the sensor detects one or both of: a non-superheated refrigerant at the compressor inlet and a temperature gradient equal to or less than 3 Kelvin between ambient and the compressor inlet.
11. The refrigerant management system according to claim 1, wherein the cold start mode is available prior to initiation of the heating mode.
12. The refrigerant management system according to claim 1, wherein the compressor is operable to draw a reverse flow of refrigerant from the heat pump condenser to the accumulator in the cold start mode.
13. The refrigerant management system according to claim 1, wherein the sensor monitors the superheat in refrigerant at the compressor inlet.
14. The refrigerant management system according to claim 13, wherein the sensor initiates the cold start mode when a superheat value is at least 10 Kelvin.
15. A vehicle comprising an engine and the refrigerant management system according to claim 1.
16. The vehicle according to claim 15, wherein the heat pump circuit comprises at least one thermodynamic cycler thermally connected to at least one of a cabin and a battery, wherein the cabin and battery are operable to remove heat.
17. The vehicle according to claim 15, wherein the engine is electrochemically powered.
18. A method of refrigerant management in an electric vehicle, comprising: a. providing the refrigerant management system according to claim 1; b. when the compressor is idle, sensing the temperature and pressure of the refrigerant at the compressor inlet with at least one sensor; c. initiating the cold start mode if the sensor detects one or both of: a superheated refrigerant at the compressor inlet and a temperature gradient of more than 3 Kelvin between the ambient temperature and the temperature at the compressor inlet; d. terminating the cold start mode and starting the heating mode or the cooling mode when the sensor detects one or both of: a non-superheated refrigerant at the compressor inlet and a temperature gradient equal to or less than 3 Kelvin between the ambient temperature and the temperature at the compressor inlet.
19. The method according to claim 18, wherein upon initiation of the cold start mode the compressor is activated before the shut off valve is opened to allow reverse refrigerant flow from the heat pump condenser to the accumulator.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) One or more embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:
(2)
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DETAILED DESCRIPTION
(8) Wherever possible, like reference numerals are used to depict similar features throughout.
(9) As shown in
(10) In
(11) The heat pump circuit 4 comprises refrigerant lines 45b, 9d and 9j arranged to fluidly connect a evaporator/dehumidifier 25 which receives heat from ambient air 19 and associated shut-off valve 23 with indirect condenser 49 and associated shut off valve 51. The evaporator/dehumidifier 25 is in fluid communication with accumulator 37 via refrigerant line 9c via cut off valve 341. Refrigerant line 9d fluidly connects the shut-off valve 23 and expansion valve 29 associated with an evaporator 31 and line 45b fluidly connects indirect condenser 49 with evaporator 31 via associated valves 51 and 29 respectively. Refrigerant line 9e fluidly connects the accumulator 37 with the compressor 11 via compressor inlet 239 in which temperature and pressure sensor 39 is located to monitor the parameters of the refrigerant at the compressor inlet 239.
(12) The heat pump circuit 4 comprises a refrigerant line 9g which is arranged to fluidly connect the outlet (213) of the compressor (11) and shut off valve 47 which is in its open position in the heat pump circuit 4. A pressure and temperature sensor 13 monitors the fluid exiting the compressor outlet 213. Refrigerant line 45a is arranged to fluidly connect the open shut-off valve 47 and an internal refrigerant to coolant heat exchanger, indirect condenser 49. The indirect condenser 49 is fluidly connected to the valves 23 and 29 associated with the evaporator/dehumidifier 25 and the evaporator 31 through shut off valve 51 in refrigerant line 45b. The evaporator/dehumidifier 25 and the evaporator 31 are each fluidly connected to the accumulator 37 via cut off valve 341 in the heating mode when associated valves 51, 23, 29, 341 are open. The accumulator 37 is fluidly connected to the inlet (239) of the compressor (11) and pressure and temperature sensor 39 is associated with the suction side of the compressor 11 and is operable monitors the fluid in line 9e at the inlet (239) of the compressor. The refrigeration lines allow the flow of refrigerant therethrough.
(13) The heat pump circuit 4 comprises a coolant circuit 8 in which line 45c is arranged to fluidly connect a coolant side of the indirect condenser 49, a temperature sensor 53, a heat pump 55 and a second internal coolant to air heat exchanger 57 thermally coupled to a heat sink, being passenger cabin 59. A three-way valve 61 downstream of heat exchanger 57 is operable to direct coolant flow back to the indirect condenser 49 via line 30b or, in a second position, to direct coolant flow to both the indirect condenser 49 via line 30b and to coolant circuit 10 via line 30c in which the coolant is directed to a heat exchanger 149 from which coolant flows via lines 30e and valve 161 with which heat exchanger 149 is fluidly coupled, via line 30h to a further heat exchanger 151 and via line 30j to a second heat sink 159, being a traction battery of an electric vehicle. Coolant in coolant circuit 10 is returned to heat exchanger 149 via line 30e an expansion header tank 167 and pump 155.
(14) In coolant circuit 10, three-way valve 161, in a second position, fluidly connects heat exchanger 149 with a coolant-refrigerant heat exchanger 131 via line 30f which can be fluidly connected at its refrigerant side to the heat pump circuit 4 (i.e. accumulator 37) when associated valve 129 is open. The coolant side of heat exchange 131 is fluidly connected to the battery 159.
(15) The components of the heat pump circuit 4 are connected by means of refrigerant pipes 9, 30, 45 which, in use, allow the flow of refrigerant through the circuit 4.
(16) Still referring to
(17) Three way valve 73 is operable to switch coolant circuit 2 into fluid communication with heat exchanger 217 when the coolant circuit is to be isolated from fluid communication with the heat pump circuit 4.
(18) The compressor 11 is fluidly coupled to each of the refrigeration cycle refrigerant circuit 6 and the heat pump circuit 4 by the shut-off valve 15 and the shut-off valve 47 respectively. Each of valves 15 and 47 are downstream from the compressor 11. The mode of operation for the vehicle heat flux management system 1 and, more specifically, the refrigerant management system 100, can be changed from a heating mode to a cooling mode depending on the direction of refrigerant flow downstream from the compressor 11 high pressure side into one of these shut-off valves 15, 47 respectively. In the cooling mode, valve 47 is closed and valve 15 is open, thereby directing refrigerant from the compressor outlet 213 to the heat pump condenser 17. In the heating mode, valve 15 is closed and valve 47 is open thereby directing refrigerant from the compressor outlet 213 to the heat pump circuit 4 and the indirect condenser 49.
(19) As shown in
(20) In the Figures, the controller 20 is operably connected to the systems 1, 100 and the components thereof. For the sake of clarity, the connections between the controller 20 and the components of the systems 1, 100 are not shown.
(21) In the cooling mode, the external air-refrigerant heat exchanger functioning as a condenser 17 is in fluid communication with the compressor 11 via lines 9a, 9b, 9c, 9j, 9g and 9f when expansion valve 21, shut off valve 41 and shut off valve 15 are in the open position. The heat pump circuit valves 47, 51, 29, are closed. Refrigerant is no longer directed to indirect condenser 49 through line 45a because shut off valve 47 is closed. Valve 23 is open in the cooling mode and the refrigeration cycle refrigerant circuit 6 and condenser 17 is in fluid communication with the compressor 11 through the evaporator/dehumidifier 25 and the accumulator 37. Valve 73 in the coolant circuit 2 is in a position to direct coolant to heat exchanger 217 within the coolant circuit 2. In this way, the coolant circuit 2 is isolated from the refrigeration cycle refrigerant circuit 6. In the cooling mode, the heat energy from the vehicle passenger cabin 25 is transferred exteriorly through the flow of refrigerant into the external heat exchangers 17, 25 which are each thermally coupled to the external ambient air 19 in the refrigeration line 9b and the refrigeration line 9c. This heat removal to the external ambient air 19 allows heat to flow from the internal cabin 59 side of the vehicle to the refrigeration cycle refrigerant circuit 6.
(22) In operation of the refrigeration cycle refrigerant circuit 6 in the cooling mode of the refrigerant management system 100, refrigerant in a state of low temperature and low pressure is drawn into the inlet 239 of the compressor 11 which is operable to transform the refrigerant into a high temperature, high pressure gas at the outlet 213 of the compressor 11. The temperature and pressure at the compressor 11 outlet is monitored by the pressure and temperature sensor 13. The refrigerant then flows in the refrigeration line 9a, through open shut off valve 15 into the external heat exchanger 17, acting as a condenser, which transfers the heat energy to the thermally coupled ambient air 19, removing heat from the system 1, which simultaneously causes the refrigerant to condense into a liquid state. The liquid refrigerant then reaches the expansion valve 21 associated with the condenser 17 through line 9b where flow is directed towards open shut off valve 23, through refrigeration line 9j and into evaporator/dehumidifier 25. Downstream of the evaporator/dehumidifier 25, the refrigerant flows through line 9c to open cut off valve 341 and into accumulator 37. Evaporator/dehumidifier 25 is thermally coupled to ambient air 19 and is operable to further remove heat from the system 100 before the refrigerant is directed to the refrigerant accumulator 37, which acts as a collector of refrigerant for supplying to the compressor 11 suction side, where a pressure and temperature sensor 39 is located. The refrigeration cycle refrigerant circuit 6 is operable to allow for refrigerant to flow downstream from the first shut-off valve 15 in the refrigeration line 9a into the refrigeration line 9f through the shut-off valve 41 into the pressure and temperature sensor 43 before being collected in the accumulator 37. In the cooling mode of system 100, valve 47 in the heating circuit is closed thereby isolating the heat pump circuit 4 from the outlet 213 of the compressor 11.
(23) As shown in
(24) By closing the shut-off valve 15 and opening the shut-off valve 47, the refrigerant downstream from the compressor 11 outlet is directed into the heat pump circuit 4 rather than the refrigeration cycle refrigerant circuit 6 of the air conditioning system in the refrigerant management system 1. Closing the shut-off valve 41 in refrigeration line 9f and the expansion valve 21 in the refrigeration line 9b disengages the external heat exchanger 17 from the system. In this heating mode, hot pressurised refrigerant gas flows downstream from the outlet 213 of the compressor 11 into the heat pump coolant circuit 8 via line 45a and indirect condenser 49. Line 45c transfers coolant to air-coolant heat exchanger 57, transferring heat energy to the internal cabin 59 through the thermal coupling between the cabin 59 and the internal heat exchanger 57 acting as a condenser. Coolant is returned to indirect condenser 49 through valve 61 and line 30b in coolant circuit 8.
(25) Refrigerant is returned from the indirect condenser 49 to the evaporator/dehumidifier 25 and the evaporator 31 through open associated valves 51, 23 and 29 respectively. The heat pump circuit 4 is completed by refrigerant from evaporator/dehumidifier 25 and evaporator 31 flowing through cut off valve 341 into accumulator 37 and on to the inlet 239 of the compressor.
(26) In the embodiments shown in
(27) The system 100 is operable to run a cold start mode as shown in
(28) As shown in
(29) In each of the circuits of
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(31) Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
(32) It will be appreciated that embodiments of the present invention can be realised in the form of hardware, software or a combination of hardware and software. Any such software may be stored in the form of volatile or non-volatile storage such as, for example, a storage device like a ROM, whether erasable or rewritable or not, or in the form of memory such as, for example, RAM, memory chips, device or integrated circuits or on an optically or magnetically readable medium such as, for example, a CD, DVD, magnetic disk or magnetic tape. It will be appreciated that the storage devices and storage media are embodiments of machine-readable storage that are suitable for storing a program or programs that, when executed, implement embodiments of the present invention. Accordingly, embodiments provide a program including code for implementing a system or method as described herein and a machine readable storage storing such a program. Still further, embodiments of the present invention may be conveyed electronically via any medium such as a communication signal carried over a wired or wireless connection and embodiments suitably encompass the same.
(33) All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
(34) Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
(35) The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.