GB2523264A

GB2523264A - Thermal management system for a vehicle, in particular a commercial vehicle

Info

Publication number: GB2523264A
Application number: GB1504930.7A
Authority: GB
Inventors: Eric Gulick; Benjamin Higgins; Matthew Rogers; Schuyler Scates; Rahul Subramanian
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2015-03-24
Filing date: 2015-03-24
Publication date: 2015-08-19
Also published as: GB201504930D0

Abstract

A thermal management system 10 for a vehicle comprises a first cooling circuit 18 containing a working fluid and comprising a compressor 20, a first heat exchanger 22 downstream of the compressor and first 28 and second 38 evaporators in parallel and downstream of the heat exchanger 22. Working fluid evaporated in evaporators 28, 38 cools air for the interior of the vehicle. An electric component 16 is cooled by coolant flowing through a second cooling circuit 42 and a chiller 44 is arranged in the first and second cooling circuits to transfer heat between the working fluid and the coolant. A valve 48 controls the flow of working fluid through evaporators 28, 38 and the chiller 44. The system may further comprise a motor 12 cooled by a medium flowing through a heating circuit 68 and second 70 and third 72 heat exchangers arranged in parallel to transfer heat from the medium to air for the interior of the vehicle. The system is suitable for heating and/or cooling two portions of a vehicle interior.

Description

Thermal Management System for a Vehicle, in particular a Commercial Vehicle The invention relates to a thermal management system for a vehicle, in particular a commercial vehicle.

US 7 789 176 B2 shows an electric vehicle thermal management system comprising a refrigeration subsystem comprising a refrigerant and a heat exchanger. The thermal management system further comprises a first coolant loop in thermal communication with an energy storage system and in thermal communication with said heat exchanger.

Moreover, the thermal management system comprises a heating, ventilation and cooling subsystem comprising a second coolant loop in thermal communication with said heat exchanger. Furthermore, a power train cooling subsystem is provided, said power train cooling subsystem comprising a third coolant loop in thermal communication with a vehicle drive motor and in thermal communication with a radiator. Additionally, the thermal management system comprises means for controllably and fluidly coupling said second coolant loop to said third coolant loop, wherein said means for controllably and fluidly coupling provides a means for allowing and preventing coolant fluid exchange between said second and third coolant loops.

Furthermore, US 7 841 431 B2 shows a method of managing thermal loads within an electric vehicle, the method comprising the step of cooling a first portion of a heat exchanger with a refrigeration system, wherein said step of cooling said first portion of said heat exchanger further comprises the steps of circulating a refrigerant within said refrigeration system and passing said refrigerant through a condenser and a thermal expansion valve. The method further comprises the step of circulating a first coolant within a first coolant loop, wherein said first coolant loop is separate from said refrigeration system and said first coolant loop is separate from said refrigerant, wherein a first portion of said first coolant loop passes through a second portion of said heat exchanger and wherein a second portion of said coolant loop is thermally coupled to an energy storage system, wherein said energy storage system is comprised of a plurality of batteries. The method further comprises a step of circulating a second coolant within a second coolant loop, wherein said second coolant loop is separate from said refrigeration system and said first coolant loop, wherein said second coolant is separate from said refrigerant, wherein a first portion of said second coolant loop passes through a third portion of said heat exchanger and wherein a second portion of said second coolant loop is thermally coupled to a vehicle passenger cabin HVAC subsystem corresponding to a vehicle passenger cabin. Furthermore, the method comprises the step of circulating a third coolant within a third coolant loop, wherein said third coolant loop is separate from said refrigeration system and first coolant loop, wherein said coolant is separate from said refrigerant, and wherein said third coolant loop is thermally coupled to a vehicle drive motor.

It is an object of the present invention to provide a thermal management system for a vehicle, by means of which thermal management system a particularly efficient and cost-effective thermal management can be realized.

This object is solved by thermal management system having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

The invention relates to a thermal management system for a vehicle, in particular a motor vehicle such as a commercial vehicle. The thermal management system according to the present invention comprises at least one first cooling circuit which is also referred to as a first coolant loop through which a working fluid can flow. Preferably, the working fluid is a liquid. The thermal management system further comprises at least one compressor arranged in the first cooling circuit, the compressor being configured to compress the working fluid. Moreover, the thermal management system comprises at least one heat exchanger arranged in the first cooling circuit downstream of the compressor, the heat exchanger being configured to cool the working fluid. For example, said heat exchanger is a condenser by means of which the working fluid can be cooled by means of convective heat transfer. For example, the working fluid is R134a, wherein the heat exchanger works to change the working fluid from a super-heated vapor to a sub-cooled liquid.

Alternatively, the working fluid can be carbon dioxide (C02), so that, for example, said heat exchanger is a gas cooler configured to cool 002.

The thermal management system according to the present invention further comprises a first evaporator arranged in the first cooling circuit downstream of the heat exchanger, the first evaporator being configured to evaporate the working fluid thereby cooling air for the interior of the vehicle. For example, the first evaporator is a heat exchanger by means of which air can be cooled. Said air cooled by the first evaporator can be guided to the interior which, thus, can be supplied with the air by the first evaporator.

Furthermore, the thermal management system comprises a second evaporator arranged in the first cooling circuit downstream of the heat exchanger, the second evaporator being configured to evaporate the working fluid thereby cooling air for the interior of the vehicle.

For example, the second evaporator is a heat exchanger configured to cool air which can be guided to the interior so that the interior can be supplied with the air cooled by the second evaporator. In the thermal management system according to the present invention, the evaporators are arranged in parallel. In other words, the first evaporator is arranged in parallel with the second evaporator so that the interior, in particular at least two portions of the interior, can be supplied with air conditioned by the first evaporator and/or the second evaporator in a need-based manner.

The thermal management system further comprises at least one second cooling circuit which is also referred to as a second cooling loop through which a coolant can flow.

Moreover, the thermal management system comprises at least one electric component such as a battery and/or an inverter, the electric component being arranged in the second cooling circuit so that the electric component can be cooled by the coolant. Moreover, the thermal management system comprises at least one chiller arranged in the first and second cooling circuits so that the first and second cooling circuits are in thermal communication via the chiller. Thus, the chiller is configured to effect a heat exchange between the working fluid and the coolant.

Additionally, the thermal management system according to the present invention comprises a valve device configured to adjust respective flows of the working fluid through the respective evaporators and the chiller. By means of the thermal management system according to the present invention fuel savings can be realized during operation by using a particularly efficient heating, ventilation and cooling (HVAC) operation as well significantly reduced fuel consumption during anti-idle operation, with an engine or a motor of the vehicle turning on occasionally to recharge the battery which can be configured as a high voltage battery (HV battery). Moreover, anti-idle interior or cabin thermal management is much more capable compared to conventional anti-idle auxiliary power unit (APU) systems.

The invention further relates to a method for operating a thermal management system according to the present invention. Advantages and advantageous embodiments of the thermal management system according to the present invention are to be regarded as advantages and advantageous embodiments of the method according to the present invention and vice versa.

Further advantages, features, and details of the invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in other combination or taken alone without leaving the scope of the invention.

The drawings show in: Fig. 1 a schematic representation of a thermal management system according to the present invention; Fig. 2 a schematic perspective view of a junction block configured to guide a working fluid in a need-based manner; and Fig. 3 a schematic sectional view of the junction block according to Fig. 2.

In the figures the same elements or elements having the same function are indicated by the same reference signs.

Fig. 1 shows a schematic representation of a thermal management system 10 for a vehicle, in particular a commercial vehicle. Said vehicle is a motor vehicle comprising at least one motor 12 which is, in the present case, configured as an internal combustion engine. Thus, the motor 12 is also referred to as an engine, wherein the motor 12 is configured to drive the vehicle. For example, the vehicle is configured as a hybrid vehicle comprising a hybrid power train. Said hybrid power train comprises the engine and at least one electric machine operable in a motor operation mode in which the electric machine acts as an electric motor to drive the vehicle. As can be seen from Fig. 1, the motor 12, in particular its output shaft, is connected to a fan 14 by means of which air for cooling the motor 12 can be conveyed.

The hybrid power train comprises a plurality of electric components such as at least one inverter and an energy storage device which is configured as a battery 16. For example, the battery 16 is a battery pack. In the present case, the battery 16 is a high voltage (HV) battery so that the battery pack is configured as a high voltage battery pack. The battery 16 is configured to store electric energy, wherein the electric machine can be supplied with the electric energy stored in the battery 16 so that the electric machine can be operated in the motor operation mode.

The thermal management system 10 comprises at least one first cooling circuit 18 through which a working fluid can flow. For example, the working fluid is a conventional refrigerant such as Ri 34a. Alternatively, the working fluid can be CO2. The thermal management system 10 comprises at least one compressor 20 arranged in a first cooling circuit 18, the compressor 20 being configured to compress the working fluid. For example, the compressor 20 is an electrically driven compressor, wherein the compressor 20 is electrically connected to the battery 16 so that the compressor 20 can be supplied with electric energy stored in the battery 16 so as to drive or operate the compressor 20 thereby compressing the working fluid. The compressor 20 is a working fluid pump working to compress a low pressure super-heated vapor into a high pressure super-heated vapor.

The thermal management system 10 further comprises a first heat exchanger 22 in the form of a condenser, since, in the present case, the working fluid is Ri 34a. The heat exchanger 22 is arranged in the first cooling circuit 18 downstream of the compressor 20, the heat exchanger 22 being configured to cool the working fluid. The condenser is a working fluid heat exchanger 22 utilizing ambient air to cool the working fluid through convective heat transfer. Said ambient air is illustrated by directional arrows 24. For example, the condenser uses ambient air either by active or passive air movement. The heat exchanger 22 works to change the working fluid from a super-heated vapor to a sub-cooled liquid. The heat exchanger 22 is equipped with a fan 26 configured as an electric fan. The fan 26 is an electrically controlled device which works to actively pull ambient air through the heat exchanger 22. Alternatively, the fan 26 could be configured as a pusher fan pushing instead of pulling ambient air through the heat exchanger 22.

The thermal management system 10 further comprises a first evaporator 28 arranged in the first cooling circuit 18 downstream of the heat exchanger 22, the first evaporator 28 being configured to evaporate the working fluid thereby cooling air for the interior 30 of the vehicle. The reference sign 30 indicates the interior as a whole, wherein the interior 30 comprises a first portion in the form of a cab 32 and a second portion in the form of a bunk 34. The driver of the vehicle can sit in the cab 32 and lie down and sleep in the bunk 34.

As can be seen from Fig. 1, the thermal management system 10 is configured to supply the cab 32 with the air cooled by the first evaporator 28. For this purpose, the thermal management system 10 comprises a first ductwork 36 configured to guide the air cooled by the first evaporator 28 into the cab 32 which is also referred to as a cabin, front cab or front cabin.

The thermal management system 10 further comprises a second evaporator 38 arranged in the first cooling circuit 18 downstream of the heat exchanger 22 in the form of a condenser, the second evaporator 38 being configured to evaporate the working fluid thereby cooling air for the interior 30. As can be seen from Fig. 1, the thermal management system 10 comprises a second ductwork 40 configured to guide the air cooled by the second evaporator 38 into the bunk 34 so that the bunk 34 can be supplied with the air cooled by the second evaporator 38. Moreover, the evaporators 28 and 38 are arranged in parallel. The respective evaporator 28 or 38 is a working fluid heat exchanger located inside the vehicle cabin. The respective heat exchanger works by starting with warm/humid air. This air passes over the respective evaporator 28 or 38. Inside the respective evaporator 28 or 38 is the cooled working fluid. As the warm/humid air passes through the respective evaporator 28 or 38 it exchanges heat thus cooling the air past the saturated liquid point. The air then exits the respective evaporator 28 or 38 and enters the vehicle cabin, i.e. the interior 30 as conditioned air.

Moreover, the thermal management system 10 comprises at least one second cooling circuit 42 through which a coolant, in particular liquid coolant can flow. As can be seen from Fig. 1, at least one electric component in the form of the battery 16 is arranged in the second cooling circuit 42. Alternatively or additionally, said inverter is arranged in the second cooling circuit 42 so that both the battery 16 and the inverter can be cooled by means of the coolant.

The thermal management system 10 further comprises a chiller 44 arranged in the first and second cooling circuits 18 and 42 so that the cooling circuits 18 and 42 are in thermal communication via the chiller 44. Thus, the chiller 44 is configured to effect a heat exchange between the working fluid and the coolant. This means the chiller 44 is a working fluid to liquid heat exchanger taking initially warm/hot coolant and passes this coolant through the heat exchanger in form of the chiller 44 where it interfaces the cold working fluid. Through heat exchange the working fluid warms and the coolant cools down. Each of the fluids then leaves the chiller 44. This means the coolant temperature at an inlet of the chiller 44 is higher than the coolant temperature at an outlet of the chiller 44. The working fluid temperature at the inlet of the chiller 44 is lower than the working fluid temperature at the outlet of the chiller 44. Thereby, the battery 16 and the inverter can be cooled by means of the coolant which in turn can be cooled by means of the working fluid via the chiller 44. At least one pump 46 is arranged in the second cooling circuit 42, the pump 46 being configured to pump or convey the coolant through the second cooling circuit 42. This means the pump 46 is a water pump for a secondary loop refrigeration system for said battery pack. For example, at least one second pump is arranged in the second cooling circuit 42 so that the pump 46 is a first pump arranged in the cooling circuit 42. In other words, the pump 46 is a water pump being an electrically driven pump providing work into a system by moving/pumping the working fluid or the coolant through the second cooling circuit 42 being a closed loop system to a required location.

Additionally, the thermal management system 10 comprises a valve device 48 configured to adjust respective flows of the working fluid through the respective evaporators 28 and 38 and the chiller 44. In the present case, the valve device 48 comprises respective valve elements 50, 52 and 54 each comprising an integrated thermal expansion valve (TXV) and a solenoid valve. The respective TXV is configured to expand the working fluid, wherein the respective solenoid valve is configured to adjust or control the respective flow of the working fluid through the respective evaporator 28 or 38 or the chiller 44. As can be seen from Fig. 1, in the present case, the respective valve elements 50, 52 and 54 are arranged upstream of the respective evaporators 28 and 38 and the chiller 44. In the present case, the valve elements 50, 52 and 54 are individual valves arranged in parallel branches of the first cooling circuit 18. Alternatively, the valve elements 50, 52 and 54 can be incorporated into or configured as a multiple distributing device configured to control the flows of the working fluid to the evaporators 28 and 38 and the chiller 44. In other words, a multi-way valve can be used instead of the individual valve elements 50, 52 and 54.

The respective TXV is a mechanically driven component that converts a high pressure/high temperature working fluid to a low pressure/low temperature working fluid throttling a valve. This valve is throttled open and closed depending on the pressure of the working fluid leaving the evaporator 28 or 38. The respective solenoid valve is also referred to as a solenoid which is a component and opens and closes based on an electrical input. The solenoid is a normally closed (NC) device for the present system configuration. When energy is supplied to the solenoid it opens and allows the working fluid to pass through the accompanying lxv to the respective heat exchanger in the form of the respective evaporator 28 or 38 or the chiller 44. As can be seen from Figs. 2 and 3, a junction block 56 is used to guide the working fluid coming from the heat exchanger 22 to the valve elements 50, 52 and 54 and the evaporators 28 and 38 and the chiller 44.

Moreover, the junction block 56 is used to merge the respective flows flowing through the evaporators 28 and 38 and the chiller 44 downstream of the evaporators 28 and 38 and the chiller 44. The junction block 56 is a manifold type component designed to take the working fluid from a single source and divert it to the system requiring the working fluid. In Fig. 3, directional arrows 58 illustrate the respective flows of the working fluid to the evaporators 28 and 38 and the chiller 44. Moreover, in Fig. 3, directional arrows 60 illustrate respective flows of the working fluid returning from the evaporators 28 and 38 and the chiller 44. A duct 62 is used to guide the working fluid returning from said components in form of the evaporators 28 and 38 and the chiller 44, wherein a duct 64 is used to supply said components with the working fluid.

In a different embodiment of the invention, the valve device 48 can be a part of the junction block 56, wherein the valve elements 50, 52 and 54 are arranged inside the junction block 56 directly at the branch offs to the evaporators 28 and 38 and the chiller 44.

As can be seen from Fig. 1, a pressure sensor 66 is arranged in the first cooling circuit 18 downstream of the heat exchanger 22 and upstream of the valve device 48 so that the pressure sensor 66 is configured as a high side pressure sensor. For example, the pressure sensor 66 is a pressure transducer being a system measurement sensor. The pressure sensor 66 measures the working fluid pressure and transmits this variable pressure through a variable voltage electronic signal.

The battery 16 is a high voltage battery being an energy storage reservoir. Thus, the vehicle comprises an electric system obtaining a surplus energy stored in the battery 16.

When said electric system, in particular the electric machine, requires electric energy, it uses energy stored in the battery 16. This system battery 16 is a high voltage battery.

Said inverter is an electrical device that changes an electrical energy from direct current (DC) to alternating current (AC).

Moreover, the thermal management system 10 comprises a heating circuit 68 used to heat air the interior 30 can be supplied with. A medium such as a liquid can flow through the heating circuit 68. With respect to the motor 12 the heating circuit 68 is a cooling circuit since -as will be described in the following -the motor 12 can be cooled by means of the medium flowing through the heating circuit 68. As can be seen from Fig. 1, the motor 12 is arranged in the heating circuit 68, wherein the motor 12 is capable of being cooled by the medium thereby heating the medium. A second heat exchanger 70 is arranged in the heating circuit 68, wherein the heat exchanger 70 is arranged in the heating circuit 68 downstream of the motor 12. The heat exchanger 70 is configured to heat air due to a heat transfer from the medium to the air via the heat exchanger 70, wherein the heated air can be supplied to the cab 32. Moreover, a third heat exchanger 72 is arranged in the heating circuit 66 downstream of the motor 12. The third heat exchanger 72 is configured to heat air due to a heat transfer from the medium to the air via the third heat exchanger 72, wherein the heated air can be supplied to the bunk 34.

As can be seen from Fig. 1, in the present case, the second and third heat exchangers 70 and 72 are arranged in parallel. The heat exchanger 70 is arranged in series with the evaporator 28, wherein the heat exchanger 72 is arranged in series with the evaporator 38. The thermal management system 10 further comprises an adjusting element in the form of a flap 74 configured to adjust a flow of air through the heat exchanger 70.

Moreover, the thermal management system 10 comprises a further adjusting element in the form of a flap 76 configured to adjust a flow of air through the heat exchanger 72.

Thus, the respective flap 74 or 76 is also referred to as a mix door, wherein the flap 74 is a cab-mix door and the flap 76 is a bunk-mix door. Since the respective heat exchanger or 72 is used to heat air, the respective heat exchanger 70 or 72 is also referred to as a heater or heater core.

Furthermore, the thermal management system 10 comprises a first blower 76 configured to blow and, thus, convey air to the first evaporator 28 and the second heat exchanger 70.

Moreover, the thermal management system comprises a second blower 80 configured to blow and, thus, convey air to the second evaporator 36 and the third heat exchanger 72.

By means of the respective flap 74 or 76 the respective flow of air can be adjusted in such a way that the air flowing through the respective evaporator 28 or 38 completely flows through the respective heat exchanger 70 or 72 thereby heating the air. Moreover, the flow of air can be adjusted in such a way that the air flowing through the respective evaporator 28 or 38 completely bypasses the respective heat exchanger 70 or 72 so that the air is not heated by the respective heat exchanger 70 or 72. Moreover, the flow of air can be adjusted in such a way that a first portion of the air flowing through the respective evaporator 28 or 38 bypasses the respective heat exchangers 70 or 72, and a second portion of the air flowing through the respective evaporator 28 or 38 flows through the respective heat exchanger 70 or 72 so that said first portion is not heated by means of the respective heat exchanger 70 or 72, and the respective second portion is heated by the respective heat exchanger 70 or 72. Downstream of the respective heat exchangers 70 or 72 the first and second portions are mixed thereby forming a combined flow of air which is then supplied to the interior 30, i.e. the cab 32 or the bunk 34 respectively. For example, the respective heat exchangers (evaporator 28 and heat exchanger 70 or evaporator 38 and heat exchanger 72) can be arranged in series, in parallel or in series/parallel.

The thermal management system 10 further comprises at least one fuel-fired heater 82 arranged in the heating circuit 68, the fuel-fired heater 82 being configured to heat the medium by burning fuel, the medium, for the motor 12, being a coolant flowing through the heating circuit 68. For this purpose the fuel-fired heater 82 is fluidically connected to a tank 84 configured to store fuel, in particular liquid fuel so that the fuel-fired heater 82 can be supplied with fuel stored in the tank 84. For example, the tank 84 is a tank for storing fuel for the engine so that the engine can be supplied with fuel stored in the tank 84.

Preferably, the fuel-fired heater 82 has an operating voltage of 12 Volts and is activated when the engine (motor 12) is off. Thus, by means of the fuel-fired heater 82 an auxiliary heating system is realized so that, for example, the interior 30 can be heated when the engine is switched off so that an anti-idle system can be realized. Preferably, the fan 26 has an operational voltage of 12 Volts and/or a variable speed and/or an electrical power of 350 Volts. Particularly, the fan 26 is used to maintain an at least substantially constant high side pressure. Moreover, for example, the compressor 20 has a variable speed.

Moreover, the thermal management system 10 comprises a first temperature sensor 86 configured to detect a temperature in the cab 32 so that the temperature sensor 86 is configured as a cabin interior air temperature sensor. Moreover, the thermal management system 10 comprises a second temperature sensor 88 configured to detect a temperature in the bunk 34 so that the second temperature sensor 88 is configured as a bunk interior air temperature sensor. A cabin interior air temperature request determines the required evaporator exit air temperature, wherein the compressor 20 controls the respective evaporator to that temperature. As can be seen from Fig. 1, the fuel-tired heater 82 is arranged downstream of the branch duct of the second heat exchanger 70 and upstream of the third heat exchanger 72.

For example, the evaporator 28 and the second heat exchanger 70 are components of a tront control unit (FCU), wherein the evaporator 38 and the third heat exchanger 72 are components of an auxiliary control unit (ACU). For example, the FCU, the ACU and the chiller 44 are components of an electric heating, ventilation and air conditioning system (HVAC system) which is also reterred to as an eHVAC system. Said eHVAC system has tour different operating modes: a front control unit mode, a front control unit and auxiliary control unit mode, an auxiliary control unit mode and a chiller mode. By opening and closing the solenoids and controlling the speed of the compressor 20 it is possible to utilize the thermal management system components tor optimal energy consumption.

In the following, the front control unit (FCU) mode is explained, the FCU mode being also referred to as a FCU only mode: Operating the eHVAC-system with only the FCU is desired for when the vehicle has an adequate amount of cooling in the front cab 32. For example, the vehicle is a tractor configured to pull a trailer. Thus, there is no requirement tor cooling on the bunk 34 which is also referred to as a sleeper cabin. This contiguration would also simulate a day cab configured tracker.

As the working fluid leaves the compressor 20 being a compressor pump, it is a high pressure/high temperature super-heated vapor. The working fluid then travels to the heat exchanger 22 where an airside energy exchange with the ambient air happens. The air moves across the heat exchanger 22 by way ot active input (heat exchanger mounted electric tan 26), passive input (ram air as the vehicle drives down the road) or a combination of both. As the working fluid leaves the heat exchanger 22 it is now a high pressure/medium temperature sub-cooled liquid. After the working tluid leaves the heat exchanger 22 it travels past the high side pressure transducer in the form of the pressure sensor 66. This transducer provides a reading of the system pressure. Based on this pressure reading a eHVAC control logic will determine if the compressor state can be on or ott and/or determine if the electrical heat exchanger tan status can be on or off. Once the working tluid travels past the high side pressure transducer it enters a manifold block in the form of the junction block 56. This is where the working fluid splits into different branches depending on which branch is requesting the working fluid. A first one of said branches comprises the ECU, a second one of said branches comprises the ACU and the third branch comprises the chiller 44.

When in ECU only operation or FCU only mode, the liquid side solenoid valves are closed on the ACU and chiller TXV's. With only the liquid side solenoid valve of the ECU TXV opened the working fluid passes through the ECU TXV and changes from a high pressure/medium temperature to a low pressure/low temperature quality (part liquid and part vapor) working fluid. As the working fluid passes through the ECU evaporator 28 it exchanges energy with either outside or cabin interior air which changes the working fluid from a quality to a low pressure/low temperature super-heated vapor. The working fluid then travels back to the manifold block (junction block 56) where the ECU, ACU and chiller branches again join. Erom here the working fluid travels back to the compressing pump in the form of the compressor 20 to start the system cycle again.

In the following, the FCU and ACU mode will be explained: Operating the eHVAC system with both the FCU and ACU is desired for when the tractor has operators in both the front and sleeper cabins or when the tractor operator is pre-conditioning the sleeper cabin (bunk 34) for an upcoming rest. As the working fluid leaves the compressor 20, it is a high pressure/high temperature super-heated vapor. The working fluid then travels to the heat exchanger 22 where an airside energy exchange with the ambient air happens. The air moves across the heat exchanger 22 by way of active input (heat exchanger mounted electric fan 26), passive input (ram air as the vehicle drives down the road) or a combination of both. As the working fluid leaves the heat exchanger 22 it is now a high pressure/medium temperature sub-cooled liquid. After the working fluid leaves the heat exchanger 22 it travels past the high side pressure transducer. This transducer provides a reading of the system pressure. Based on this pressure reading the eHVAC control logic will determine if the compressor state can be on or off and/or determine if the electric heat exchanger fan status can be on or off.

Once the working fluid travels past the high side pressure transducer it enters the manifold block. This is where the working fluid splits into the different branches depending on which branch is requesting the working fluid. When in ECU and ACU mode or operation, the liquid side solenoid valve is closed on the chiller TXV. With the liquid side solenoids of the FCU and ACU TXV's open, the working fluid passes through both the ECU and ACU TXV's changing from a high pressure/medium temperature to a low pressure/low temperature quality (part liquid and part vapor) working fluid. As the working fluid passes through the ECU and ACU evaporators 28 and 38 it exchanges energy with either outside or cabin interior air which changes the working fluid from a quality to a low pressure/low temperature super-heated vapor. The working fluid then travels back to the manifold block where the ECU, ACU and chiller branches again join. From here the working fluid travels back to the compressing pump to start the system cycle again.

In the following, the ACU mode will be described, the ACU mode being also referred to as an ACU only mode: Operating the cHVAC system with only the ACU is desired for when the tractor is in a parked anti-idle operation condition and only requires cooling in the sleeper cabin, i.e. the bunk 34. Thus, there is no requirement for cooling on the front cabin, i.e. the cab 32.

As the working fluid leaves the compressing pump, it is a high pressure/high temperature super-heated vapor. The working fluid then travels to the heat exchanger 22 where an airside energy exchange with the ambient air happens. The air moves across the heat exchanger 22 by way of active input (heat exchanger mounted electric fan 26), passive input (ram air as the vehicle travels down the road) or a combination of both. As the working fluid leaves the heat exchanger 22 it is now a high pressure/medium temperature sub-cooled liquid. After the working fluid leaves the heat exchanger 22 it travels past the high side pressure transducer. This transducer provides a reading of the system pressure.

Based on this pressure reading the eHVAC control logic will determine if the compressor state can be on or off and/or determine if the electric heat exchanger fan status can be on or off. Once the working fluid travels past the high side pressure transducer it enters the manifold block. This is where the working fluid splits into the different branches depending on which branch is requesting the working fluid.

When in ACU only operation, the liquid side solenoid valves are closed on the ECU and chiller TXV's. With only the liquid side solenoid of the ACU TXV opened, the working fluid passes through the ACU TXV and changes from a high pressure/medium temperature to a low pressure/low temperature quality (part liquid and part vapor) working fluid. As the working fluid passes through the ACU evaporator 38 it exchanges energy with either outside or cabin interior air which changes the working fluid from a quality to a low pressure/low temperature super-heated vapor. The working fluid then travels back to the manifold block where the ECU, ACU and chiller branches again join. From here the working fluid travels back to the compressing pump to start the system cycle again.

In the following, the chiller mode or chiller operation will be described: Operating the eHVAC system with only the chiller 44 is desired for when the tractor is not requesting any cooling and the internal high voltage battery 16 has requested additional cooling.

As the working fluid leaves the compressing pump, it is a high pressure/high temperature super-heated vapor. The working fluid then travels to the heat exchanger 22 where it has an airside energy exchange with ambient air. The air moves across the heat exchanger 22 by way of active input (heat exchanger mounted electric fan 26), passive input (ram air as the vehicle drives down the road) or a combination of both. As the working fluid leaves the heat exchanger 22 it is now a high pressure/medium temperature sub-cooled liquid. After the working fluid leaves the heat exchanger 22 it travels past the high side pressure transducer. This transducer provides a reading of the system pressure. Based on this pressure reading the eHVAC control logic will determine if the compressor state can be on or off and/or determine if the electric heat exchanger fan status can be on or off. Once the working fluid travels past the high side pressure transducer (pressure sensor 66) it enters the manifold block. This is where the working fluid splits into the different branches depending on which branch is requesting the working fluid. When in chiller only operation, the liquid solenoid valves are closed on the ECU and ACU TXV's. With only the liquid side solenoid of the chiller TXV opened, the working fluid passes through the chiller TXV and changes from a high pressure/medium temperature to a low pressure/low temperature quality (part liquid and part vapor) working fluid. As the working fluid passes through the chiller 44 it exchanges energy with the coolant in the high voltage battery/battery inverter coolant loop being the cooling circuit 42. This changes the working fluid from a quality working fluid to a low pressure/low temperature super-heated vapor. The working fluid then travels back to the manifold block where the ECU, ACU and chiller branches again join. Erom here, the working fluid travels back to the compressing pump to start the system cycle again.

Moreover, a combined operation or combined mode is possible. At any point of system operation there may be a request from one or more of the components ECU, ACU and the chiller 44 for routing the working fluid. If this occurs, their system parameters which allow combination of a single component, two components, or all of the components (ECU, ACU and chiller 44) to be fully functional by requesting the compressor 20, electric fan 26 and TXV integrated solenoids to be opened or closed.

As mentioned above, the second cooling circuit 42 is a high voltage baftery/inverter cooling loop which, for this application, has four different operating modes: stage 1, stage 2, stage 3 and stage 4. By activating the above mentioned different water pumps (first and second water pumps), a four-way butterfly valve not shown in the figures, and the chiller 44 it is possible to utilize the system components for optimal energy consumption in order to keep the high voltage battery 16 and the inverter at desired operating conditions. For example, the four-way butterfly valve is a four-way valve which can be configured as a water valve or mixing valve being, for example, an electrically controlled device that when operated will mechanically dived the working fluid or coolant from two separate closed loops into a single working fluid closed loop. In other words, the four-way valve can be switched between at least two conditions. In a first one of said conditions the coolant flows through a single working fluid closed loop in the form of the second cooling circuit 42. In the second condition the overall cooling circuit 42 is split into two separate closed loops by means of the four-way valve so that the coolant can flow through said separate closed loops.

In the following, the stage 1 or stage 1 cooling loop will be described: This stage requires no cooling requirements. The four-way butterfly valve which is also referred to as the four-way valve is in a combined single loop state (first condition) and the water pumps (first and second water pumps) are producing a small amount of flow of the coolant.

In the following, the stage 2 or stage 2 cooling loop will be described: When requirements for this stage are met, the only required function is the water pumps. The four-way butterfly valve is in the combined single loop state (first condition) and the water pumps are moving the coolant through the system, i.e. the single working fluid closed loop.

The coolant starts in a radiator which is, for example, an air to liquid heat exchanger where it exchanges energy with the outside ambient air utilizing passive ram air from over the road vehicle velocity. The coolant then travels to the four-way butterfly valve. With the four-way butterfly valve in the combined position (first condition), the coolant then flows to the first water pump 46. From the first water pump 46 the coolant then travels to the chiller 44. Because the chiller 44 is not required at this stage of operation, the coolant passes through the chiller 44 without any active heat exchanging taking place. After the chiller 44, the coolant passes through the high voltage battery 16, where it exchanges some energy with internal battery components. The next step is for the coolant to travel back to the four-way butterfly valve and through to the second water pump. The second water pump assists the coolant on to the battery inverter where it performs another energy exchange.

The final leg is for the coolant to return back to the radiator where it will start the system cycle again.

In the following, the stage 3 or stage 3 cooling loop will be explained: When the requirements for this stage are met, the required functions are the water pumps and an electric radiator cooling fan. The four-way butterfly valve is in the combined single loop state (first condition), the water pumps are moving coolant through the system and the electric fan is providing active air movement over the radiator for air to liquid energy exchange. The coolant starts in the radiator (air to liquid heat exchanger) where it exchanges energy with the outside ambient air utilizing both active air movement from the electric radiator fan, along with passive ram air from over the road vehicle velocity. It then travels to the four-way butterfly valve. With the four-way butterfly valve in the combined position which is also referred to as the combined single loop state, the coolant then flows to the first water pump 46. From the first water pump 46 the coolant then travels to the chiller 44. Because the chiller 44 is not required at this stage of operation the coolant passes through the chiller 44 without any active heat exchanging taking place. After the chiller 44, the coolant passes through the high voltage battery 16 where it exchanges some energy with the internal battery components. The next step is for the coolant to travel back to the four-way butterfly valve and through to the second water pump. The second water pump assists the coolant on to the battery inverter, where it performs another energy exchange. The final leg is for the coolant to return back to the radiator where it will start the system cycle again.

In the following, the stage 4 or stage 4 cooling loop will be explained: When requirements for this stage are met, the required functions are the water pumps, the electric radiator cooling fan, the compressor 20 and the chiller 44. Then, the four-way butterfly valve is in the closed separate loop state, i.e. the second condition. The first water pump 46 is moving coolant through the closed inverter/radiator loop and the second water pump is moving the coolant through the closed chiller 44 and high voltage battery 16 loop. In other words, one of said separate closed loops is the closed inverter/radiator loop comprising the inverter and the radiator. The second one of said separate closed loops is the closed chiller and high voltage battery loop comprising the chiller 44 and the battery 16. This means the system circuit, in particular the cooling circuit 42 is now divided into two separate closed loops since the four-way butterfly is closed, i.e. in its second condition.

The closed inverter/radiator loop is also referred to as an inverter loop.

In the following the inverter loop will be explained: The coolant starts in the radiator (air to liquid heat exchanger) whore it exchanges energy with the outside ambient air utilizing both active air movement from the electric radiator fan, along with passive ram air from over the road vehicle velocity. It then travels to the four-way butterfly valve. With the four-way butterfly valve in the closed position, i.e. the second condition (separate system loops state), the coolant then flows to the system's second water pump. The second water pump assists the coolant on to the battery inverter where it performs another energy exchange. The final leg is for the coolant to return back to the radiator where it will start the system cycle again.

In the following, the closed chiller and high voltage battery loop will be explained, the closed chiller and high voltage battery loop being also referred to as a high voltage battery loop: The coolant flows from the four-way butterfly valve to the system's first water pump 46. From the first water pump 46, the coolant then travels to the chiller 44. Because the chiller 44 is now required, the compressor 20 is engaged or activated and the solenoid on the chiller TXV is open. This allows the working fluid to move through the chiller 44. As the high voltage battery loop coolant flows through the chiller 44 it exchanges energy with the working fluid so that the coolant becomes cool. After the chiller 44, the coolant passes through the high voltage battery 16 where it exchanges more energy (becomes warmer) with the internal battery components. The next step is for the coolant to travel back to the four-way butterfly valve and into the systems first water pump 46 where it will start the cycle again.

The pressure transducer (pressure sensor 66) provides the same functions as using separate binary and fan cycling switches. As the pressure changes it provides an output signal to an ECU (electronic control unit). Depending on the provided signal, the ECU then allows the A/C components to turn on or off.

When the NC system, i.e. the first cooling circuit 18 is requested the system pressure must already be at a minimum value to start (set point 1). This set point 1 is required to prevent damage to the compressor 20 from engaging without a refrigerant charge. As the pressure increases the heat exchanger fan 26 is then engaged (set point 2). The final set point for the system pressure increase is to turn the compressor off (set point 3) to prevent system damage from too much pressure. Starting from the high end system working pressure, as the pressure starts to decrease, the compressor 20 is requested to engage (set point 1). When the system pressure continues to decrease, the next set point turns off the heat exchanger fan 26 (set point 2). The last set point (set point 3) turns off the compressor 20. This last set point 3 is to again prevent system damage for not having enough working fluid/lubrication in the system.

The compressor speed is driven or controlled based on algorithms and system priority controllers. The FCU and ACU use an algorithm to request a specific evaporator temperature. Depending on the calculated temperature request, the compressor 20 will then increase or decrease speed to acquire this requested evaporator temperature. The chiller 44 uses an algorithm to request a compressor speed based on what the current temperature of the hybrid battery 16 is and what is required to bring the hybrid battery temperature down to the required operating state.

In the following, priority controls will be explained: There are three systems that can request a compressor speed setting. A first one of said system is the ECU, a second one of said system is the ACU and the third system is the chiller 44. Depending on which system is active, the compressor speed setting is selected accordingly: 1. If only the eHVAC requests cooling, then the compressor speed request from the eHVAC system drives the final compressor speed.

2. If only the chiller 44 requests cooling, then the chiller compressor speed request drives the final compressor speed.

3. If both the eHVAC and chiller 44 requires system working fluid, then the maximal algorithm speed request drives the final compressor speed.

The idea behind the thermal management system is that in the past conventional anti-idle systems were not as capable or integrated as they could be. With the addition of a hybrid power train system, a new cooling system had to be developed in the form of the thermal management system 10. These two systems (hybrid power train thermal management and cabin thermal management) have been integrated as one, i.e. in the thermal management system 10. Additionally, with electrical compressor capacity restrictions there is a need to determine what systems need thermal conditions along with system priorities. The vehicle (cabin and hybrid) thermal management is now controlled by system priority inputs. This in turn routes the fluid medium to the appropriate subsystem as required.

The eHVAC system, when integrated as part of a hybrid system, will lead to a more cost-effective implementation of a proprietary heavy duty hybrid system and will also negate the need for the additional complexity of an HVAC anti-idle system which is also referred to as an auxiliary power unit (APU). Fuel savings are realized during operation by using a more efficient eHVAC operation as well as significantly reduced fuel consumption during anti-idle operation with the engine turning on occasionally to recharge the high voltage battery 16. Anti-idle cabin thermal management is much more capable compared to existing anti-idle APU systems. For example, a pusher fan in front of the heat exchanger 22 could be used instead of the puller fan 26, however, the puller fan 26 is more efficient.

Instead of separating the refrigerant loop, it could be possible to leave the heat exchanger 22 as part of the main cooling module and the pusher fans in front of the entire cooling module which, however, would be less efficient. It could be further possible to remove said four-way valve in the hybrid cooling loop (cooling circuit 42). However, this would leave battery cooling solely up to the chiller 44 and inverter cooling solely up to the radiator.

However, there is a benefit from utilizing different modes depending on system requirements for added efficiency.

List of reference signs thermal management system 12 motor 14 fan 16 battery 18 first cooling circuit compressor 22 heat exchanger 24 directional arrows 26 fan 28 first evaporator interior 32 cab 34 bunk 36 first ductwork 38 second evaporator second ductwork 42 second cooling circuit 44 chiller 46 first water pump 48 valve device valve element 52 valve element 54 valve element 56 junction block 58 directional arrow directional arrow 62 duct 64 duct 66 pressure sensor 68 heating circuit second heat exchanger 72 third heat exchanger 74 flap 76 flap 78 blower blower 82 fuel-fired heater 84 tank

Claims

Claims A thermal management system (10) for a vehicle, the thermal management system (10) comprising: -at least one first cooling circuit (18) through which a working fluid can flow; -at least one compressor (20) arranged in the first cooling circuit (18), the compressor (20) being configured to compress the working fluid; -at least one heat exchanger (22) arranged in the first cooling circuit (18) downstream of the compressor (20), the heat exchanger (22) being configured to cool the working fluid; -a first evaporator (28) arranged in the first cooling circuit (18) downstream of the heat exchanger (22), the first evaporator (28) being configured to evaporate the working fluid thereby cooling air for the interior (30) of the vehicle; -a second evaporator (38) arranged in the first cooling circuit (18) downstream of the heat exchanger (22), the second evaporator (38) being configured to evaporate the working fluid thereby cooling air for the interior (30) of the vehicle, wherein the evaporators (28, 38) are arranged in parallel; -at least one second cooling circuit (42) through which a coolant can flow; -at least one electric component (16) arranged in the second cooling circuit (42), the electric component (16) being capable of being cooled by the coolant; -at least one chiller (44) arranged in the first and second cooling circuits (18, 42), the chiller (44) being configured to effect a heat exchange between the working fluid and the coolant; and -a valve device (48) configured to adjust respective flows of the working fluid through the respective evaporators (28, 38) and the chiller (44).
2. The thermal management system (10) according to claim 1, wherein the thermal management system (10) comprises: -a heating circuit (68) through which a medium can flow; -at least one motor (12) arranged in the heating circuit, the motor (12) being configured to drive the vehicle and capable of being cooled by the medium thereby heating the medium; -at least one second heat exchanger (70) arranged in the heating circuit (68) downstream of the motor (12), the second heat exchanger (70) being configured to heat air for the interior due to a heat transfer from the medium to the air via the second heat exchanger (70); and -at least one third heat exchanger (72) arranged in the heating circuit (68) downstream of the motor (12), the third heat exchanger (72) being configured to heat air for the interior due to a heat transfer from the medium to the air via the third heat exchanger (72), wherein the second and third heat exchangers (70, 72) are arranged in parallel.
3. The thermal management system (10) according to claim 2, wherein the first evaporator (28) and the second heat exchanger (70) are arranged in series so as to, by means of the second heat exchanger (70), heat at least a portion of the air cooled by the first evaporator (28), and wherein the second evaporator (38) and the third heat exchanger (72) are arranged in series so as to, by means of the third heat exchanger (72), heat at least a portion of the air cooled by the second evaporator (38).
4. The thermal management system (10) according to claim 2 or 3, wherein at least one fuel-fired heater (82) is arranged in the heating circuit (68), the fuel-fired heater (82) being configured to heat the medium by burning fuel.
5. The thermal management system (10) according to claim 4, wherein the fuel-fired heater (82) is arranged downstream of the branch duct of the second heat exchanger (70) and upstream of the third heat exchanger (72).
6. The thermal management system (10) according to any one of the preceding claims, wherein the thermal management system (10) is configured to supply a first portion (32) of the interior (30) with the air cooled by the first evaporator (28) and/or heated by the second heat exchanger (70), and wherein the thermal management system (10) is configured to supply a second portion (34) of the interior (30) with the air cooled by the second evaporator (38) and/or heated by the third heat exchanger (72).
7. The thermal management system (10) according to claim 6, wherein the second portion (34) of the interior (30) is arranged behind the first portion (32) of the interior (30) in the longitudinal direction of the vehicle.
8. The thermal management system (10) according to claim 7, wherein the second portion (34) of the interior (30) is a bunk (34) and the first portion (32) of the interior (30) is a cab (32) of the vehicle.
9. A method for operating a thermal management system (10) according to any one of the preceding claims.