COOLING SYSTEM FOR A HYBRID VEHICLE AND A CONTROL METHOD THEREOF

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0180994, filed with the Korean Intellectual Property Office on Dec. 6, 2024, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Field

The present disclosure relates to a cooling system for a hybrid vehicle, and more particularly, the present disclosure relates to a cooling system for a hybrid vehicle applied to a hybrid vehicle using power sources of an engine and a motor.

(b) Description of the Related Art

Recently, due to growing interest in energy efficiency and concerns over environmental pollution, the development of environmentally-friendly vehicles that can substantially replace internal combustion engine vehicles has become necessary. Such environmentally-friendly vehicles are generally classified into electric vehicles, which use fuel cells or electricity as a power source, and hybrid vehicles, which are powered by both an engine and an electrical battery.

In the electric vehicle, driving force is generated using electrical energy produced by converting chemical reaction energy between oxygen and hydrogen into the electrical energy. During this process, heat is generated by the chemical reaction in the fuel cell. Therefore, to ensure proper performance of the fuel cell, it is desired to effectively dissipate the generated heat.

Further, a hybrid vehicle generates a driving torque by driving a motor using electricity that is supplied from the fuel cell or a battery together with an engine operating with a typical fuel, and when effectively removing a heat generated from electrical components such as a Hybrid Power Control Unit (HPCU), an Oil Pump Control Unit (OPU), a Hybrid Starter Generator (HSG), and an inverter, a performance of the motor may be secured.

In hybrid vehicles, a separate cooling apparatus must be applied to efficiently cool the engine, motor, and multiple electrical components that generate a significant amount of heat.

Additionally, hybrid vehicle engines are equipped with intercoolers to cool the supplied air, and a separate cooling apparatus must also be applied to cool the intercooler.

Accordingly, hybrid vehicles generally use a water-cooled cooling system consisting of individual cooling apparatuses that cool the engine, the intercooler, and electrical components by using the cooled coolant. Here, devices such as a radiator, a reservoir tank, and a water pump are essentially required in each cooling apparatus.

However, the conventional hybrid vehicle has a drawback in that, together with individual cooling apparatuses for preventing heat generation of the engine, motor, electrical components, and battery and an air conditioning system for cooling or heating the vehicle interior, a separate cooling apparatus for cooling the intercooler is essentially required, which causes the manufacturing cost and weight to increase, and it is difficult to secure a space for installing the cooling system.

In addition, a radiator for cooling the coolant is necessarily configured in each cooling apparatus, and this causes a drawback in that the size and weight of a cooling module mounted on the front of the vehicle may increase, and the layout of connection pipes for supplying the refrigerant or coolant to respective apparatuses becomes complicated in a narrow engine compartment.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure, and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.

SUMMARY

The present disclosure provides a cooling system for a hybrid vehicle and a control method thereof, which reduce the number of components, thereby lowering the manufacturing costs and vehicle weight, by using an electrical component cooling apparatus, configured to cool an electrical component, to also cool an intercooler.

In an embodiment of the present disclosure, a cooling system for a hybrid vehicle may include: a cooling module disposed on a front side of a vehicle and including a cooling fan; and an engine cooling apparatus including a first line through which a first coolant flows. In particular, the first line connects the cooling module and an engine of the hybrid vehicle. The cooling system further includes: an intercooler provided in the engine; and an electrical component cooling apparatus including a water pump, and a second line connected to the cooling module, the water pump, and an electrical component. The second line is configured to allow a second coolant to flow through the second line. The cooling system further includes a controller configured to control an operation of the cooling fan and the water pump. In particular, the intercooler is disposed on a branch line that is connected to the second line to circulate the second coolant, and the intercooler is disposed in parallel with the electrical component via the branch line.

A first end of the branch line may be connected to the second line between the water pump and the electrical component, and a second end of the branch line may be connected to the second line between the cooling module and the electrical component.

The second line and the branch line may be formed with different inner diameters to vary flow resistance.

An air temperature sensor may be provided on the intercooler and electrically connected to the controller, and the air temperature sensor is configured to measure a temperature of the air.

An electrical component temperature sensor may be provided on the electrical component and electrically connected to the controller, and the electrical component temperature sensor is configured to measure a temperature of the electrical component.

A coolant temperature sensor may be provided on the branch line and electrically connected to the controller, and the coolant temperature sensor is configured to measure a temperature of the second coolant flowing through the branch line.

The cooling module may further include: a first radiator connected to the first line and configured to cool the first coolant through exchanging heat with an ambient air; and a second radiator connected to the second line and configured to cool the second coolant through exchanging heat with the ambient air.

The second radiator may be disposed on an upstream side of the first radiator, and the cooling fan may be disposed on a downstream side of the first radiator.

The water pump may be an electric water pump, and a rotational speed (e.g., RPM) of the water pump is controlled according to a control signal from the controller.

A reservoir tank may be disposed on the second line.

In another embodiment of the present disclosure, a control method for a cooling system for a hybrid vehicle is provided, where the hybrid vehicle includes: an engine, an engine cooling apparatus provided on a first line through which a first coolant flows, an electrical component cooling apparatus including a water pump provided on a second line through which a second coolant flows, an electrical component disposed on the second line, and an intercooler disposed in parallel with the electrical component through a branch line connected to the second line, and the control method includes: converting, by a controller, requested RPMs of the water pump and operation duties of a cooling fan based on data detected from a data detector during starting and operation of the hybrid vehicle. The control method further includes: driving the water pump and the cooling fan by selecting a maximum requested RPM and a maximum operation duty among the converted requested RPMs of the water pump and the converted operation duties of the cooling fan; and determining, by the controller, whether an air temperature and a temperature of the electrical component are in a range of upper and lower allowable temperatures based on predetermined reference temperatures and data detected in real time from the data detector, and then controlling the RPM of the water pump and the operation duty of the cooling fan.

In an embodiment, converting requested RPMs and operation duties may include: determining, by the controller, the air temperature or a temperature of the second coolant and the temperature of the electrical component based on the data detected from the data detector; and converting, by the controller, the requested RPMs of the water pump and the operation duties of the cooling fan based on the determined air temperature or temperature of the second coolant and the determined temperature of the electrical component.

In an embodiment, driving the water pump and the cooling fan may include: selecting, by the controller, the maximum requested RPM and the maximum operation duty from among the converted requested RPMs of the water pump and the operation duties of the cooling fan, respectively; and driving the water pump at the maximum requested RPM, and driving the cooling fan at the maximum operation duty, by the controller.

The control method may further include determining, by the controller, whether the air temperature or a temperature of the second coolant and the temperature of the electrical component are in the range of upper and lower allowable temperatures based on the predetermined reference temperatures and the data detected in real time from the data detector; and maintaining, by the controller, the RPM of the water pump and the operation duty of the cooling fan that are currently being driven, based on determining that the air temperature or the temperature of the second coolant and the temperature of the electrical component are in the range of upper and lower allowable temperatures (i.e., the condition is satisfied).

The control method may further include, based on determining that the air temperature or the temperature of the second coolant and the temperature of the electrical component are not in the range of upper and lower allowable temperatures (i.e., when the condition is not satisfied), returning to the converting of the requested RPMs of the water pump and the operation duties of the cooling fan.

The range of upper and lower allowable temperatures may be set such that the air temperature or the temperature of the second coolant and the temperature of the electrical component are greater than or equal to a predetermined minimum reference temperature and lower than a predetermined maximum reference temperature.

The data detector may include: an air temperature sensor provided in the intercooler and configured to measure a temperature of the air introduced into the intercooler, an electrical component temperature sensor provided in the electrical component and configured to measure the temperature of the electrical component, and a coolant temperature sensor provided in the branch line and configured to measure a temperature of the second coolant.

As described above, according to a cooling system for a hybrid vehicle and a control method thereof according to an embodiment, by cooling an intercooler by using an electrical component cooling apparatus configured to cool an electrical component, the number of components can be reduced and the overall system may be simplified.

In addition, the present disclosure can facilitate securing a space for installing the cooling system through streamlining of the entire system and can improve space utilization by reducing the size and weight of a cooling module mounted on the front of the vehicle.

In addition, the present disclosure can simplify the layout of connection pipes for flowing the coolant inside the narrow engine compartment, and the flow rate of the coolant may be controlled by using the flow resistance of the coolant without employing a valve for controlling the flow direction and flow rate of the coolant.

In addition, by driving the water pump and the cooling fan at a maximum RPM and a maximum duty among the requested driving RPMs of the water pump and the operation duties of the cooling fan depending on the detected air temperature or temperature of the coolant and the temperature of the electrical component, the present disclosure can enable more efficient cooling of the electrical component and the intercooler, and can improve the performance and efficiency of the entire system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a cooling system for a hybrid vehicle according to an embodiment.

FIG. 2 is a block diagram illustrating a cooling system control apparatus to which a control method of a cooling system for a hybrid vehicle according to an embodiment is applied.

FIG. 3 is a flowchart illustrating a control method of a cooling system for a hybrid vehicle according to an embodiment.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

Some embodiments are hereinafter be described in detail with reference to the accompanying drawings.

The embodiments disclosed in the present specification and the constructions depicted in the drawings are merely exemplary and do not represent the full scope of the present disclosure. Therefore, it should be understood that various modifications, equivalents, and alternatives may be possible at the time of the implementation.

In order to clarify the present disclosure, parts that are not related to the description are omitted, and the same elements or their equivalents are denoted by the same reference numerals throughout the specification.

Also, the size and thickness of each element are arbitrarily shown in the drawings, but the present disclosure is not necessarily limited thereto, and in the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.

In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising”, should be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

Furthermore, each of terms, such as “ . . . unit”, “ . . . means”, “ . . . portions”, “ . . . part”, and “ . . . member” described in the specification, mean a unit of a comprehensive element that performs at least one function or operation. When a component, controller, device, element, apparatus, or the like of the present disclosure is described as having a purpose or performing an operation, function, or the like, the component, controller, device, element, apparatus, or the like should be considered herein as being “configured to” meet that purpose or to perform that operation or function. Each component, controller, device, element, apparatus, and the like may separately embody or be included with a processor and a memory, such as a non-transitory computer readable media, as part of the apparatus.

FIG. 1 is a block diagram of a cooling system for a hybrid vehicle according to an embodiment.

According to an embodiment, a cooling system for a hybrid vehicle is provided. The cooling system may reduce the number of components, thereby lowering the manufacturing costs and the vehicle weight, by using an electrical component cooling apparatus 20, configured to cool an electrical component 5, to also cool an intercooler 4.

Referring to FIG. 1, the cooling system may include the intercooler 4, a cooling module 7, an engine cooling apparatus 10, the electrical component cooling apparatus 20, and a controller 100.

The cooling module 7 may be disposed at a front of the vehicle, and may include a cooling fan 9.

The engine cooling apparatus 10 may include a first line 11 through which a first coolant flows and connected to the cooling module 7. An engine 3 is connected to the engine cooling apparatus 10 through the first line 11.

The engine cooling apparatus 10 may further include a water pump provided in the engine 3 or on the first line 11.

The water pump (e.g., a mechanical water pump) may be operated by the driving torque of the engine 3.

The engine cooling apparatus 10 configured may adjust a temperature of the engine 3 by circulating the first coolant along the first line 11 through an operation of a mechanical water pump.

In an embodiment, the intercooler 4 may be provided in the engine 3.

The intercooler 4 may cool an air supplied from a forced induction device such as a turbocharger or a supercharger and supply the cooled air to the engine 3.

Here, the intercooler 4 may be configured as a water-cooled intercooler configured to cool the air supplied from the forced induction device by using the coolant.

In an embodiment, the electrical component cooling apparatus 20 may include a water pump 23, and a second line 21 connected to the cooling module 7, the water pump 23, and an electric component 5. The second line allows a second coolant to flow through the second line. In other words, the electrical component 5 and a water pump 23 are connected to each other through the second line 21.

Here, the electrical component 5 may include a Hybrid Power Control Unit (HPCU), or an Oil Pump Control Unit (OPU), or a Hybrid Starter Generator (HSG), or an inverter, or the like.

In addition, the electrical component 5 may further include an electric power control unit (EPCU), or an on-board charger (OBC), or an autonomous driving controller, or the like.

In addition, a reservoir tank 27 may be provided on the second line 21.

Although it is described that the reservoir tank 27 is provided on the second line 21, it is not limited thereto, and the reservoir tank 27 may be connected to the second line 21 through a separate line through which the second coolant flows.

The electrical component cooling apparatus 20 may adjust a temperature of the electrical component 5 by circulating the second coolant along the second line 21 via operation of the water pump 23.

Here, the cooling module 7 may further include a first radiator 12 and a second radiator 22.

The first radiator 12 may be connected to the first line 11 and may cool the first coolant through exchanging heat with an ambient air.

Here, the first radiator 12 may be disposed at the front of the vehicle. The cooling fan 9 may be disposed on a downstream side of the first radiator 12. Accordingly, the first radiator 12 may cool the first coolant through operation of the cooling fan 9 and exchanging heat with the ambient air.

In addition, the second radiator 22 may be connected to the second line 21 and may cool the second coolant through exchanging heat with the ambient air.

The second radiator 22 may be disposed on an upstream side of the first radiator 12 and may cool the second coolant through the operation of the cooling fan 9 and exchanging heat with the ambient air.

In an embodiment, the intercooler 4 may be disposed on a branch line 25 connected to the second line 21 to circulate the second coolant. The intercooler 4 may be disposed in parallel with the electrical component 5 through the branch line 25. In other words, the intercooler 4 is arranged in parallel configuration with the electrical component 5 via the branch line 25 connected to the second line 21.

A first end of the branch line 25 may be connected to the second line 21 between the water pump 23 and the electrical component 5.

A second end of the branch line 25 may be connected to the second line 21 between the second radiator 22 provided in the cooling module 7 and the electrical component 5, based on a flow direction of the second coolant.

Here, the second line 21 may be formed in a different inner diameter from the branch line 25.

Accordingly, in the electrical component cooling apparatus 20, when the second coolant flows through the second line 21 and the branch line 25, which have different inner diameters, the flow rates of the second coolant flowing through the respective lines may be controlled to be different from each other by using the flow resistance of the second line 21 and the branch line 25.

In other words, in the embodiment, the intercooler 4 may be cooled by the second coolant through integration with the electrical component cooling apparatus 20, which operates at a similar temperature of the supplied coolant.

Accordingly, in the embodiment, a separate cooling apparatus—conventionally used to cool the intercooler 4 and including a radiator, a line, and a water pump—may be eliminated.

In addition, the controller 100 may be electrically connected to the cooling fan 9 and the water pump 23 so as to control the operation of the cooling fan 9 and the water pump 23.

Here, the water pump 23 may be an electric water pump capable of controlling a rotational speed (e.g., RPM) according to a control signal of the controller 100.

In an embodiment, an air temperature sensor 112 may be provided in the intercooler 4 and electrically connected to the controller 100. The air temperature sensor 112 is configured to measure a temperature of the air.

In addition, an electrical component temperature sensor 114 may be provided in the electrical component 5 and electrically connected to the controller 100. The electrical component temperature sensor 114 may measure the temperature of the electrical component 5.

In addition, a coolant temperature sensor 116 may be provided on the branch line 25 at an upstream end of the intercooler 4 and electrically connected to the controller 100. The coolant temperature sensor 116 may measure a temperature of the second coolant flowing through the branch line 25.

Accordingly, the controller 100 may control an operation of the cooling fan 7 and the water pump 23 according to the signals output from the air temperature sensor 112, the electrical component temperature sensor 114, and the coolant temperature sensor 116.

Hereinafter, a control method of a heat pump system for a vehicle configured as described above is described with reference to FIG. 2 and FIG. 3.

FIG. 2 is a block diagram showing a cooling system control apparatus to which a control method of a cooling system for a hybrid vehicle according to an embodiment is applied, and FIG. 3 is a control flowchart fillustrating a control method of a cooling system for a hybrid vehicle according to an embodiment.

As shown in FIG. 2, in a cooling system for a hybrid vehicle configured as described above, the cooling fan 9 and the water pump 23 included in the electrical component cooling apparatus 20 may be controlled by the cooling system control apparatus, and the cooling system control apparatus may include the controller 100 and data detector 110.

In an embodiment, the data detector 110 may detect data used by the controller 100 to control the operation of the cooling fan 9 and the water pump 23.

The data detected by the data detector 110 may be transferred to the controller 100. The data detector 110 may include at least one of the air temperature sensor 112, the electrical component temperature sensor 114, or the coolant temperature sensor 116.

The air temperature sensor 112 may measure a temperature of the air supplied to the intercooler 4 and may transfer corresponding signals to the controller 100.

The electrical component temperature sensor 114 may measure a temperature of the electrical component 4 while the vehicle is driving and may transfer corresponding signals to the controller 100.

In addition, the coolant temperature sensor 116 may measure the temperature of the second coolant introduced into the intercooler 4.

The coolant temperature sensor 116 may measure the temperature of the second coolant introduced into the intercooler 4 through the branch line 25 and may transfer corresponding signals to the controller 100.

Here, the controller 100 may be implemented as one or more processors operated by a predetermined program, and the predetermined program may include a set of instructions for performing respective steps included in a control method of a cooling system according to an embodiment described below.

Accordingly, in a control method of a cooling system for a hybrid vehicle according to an embodiment, the controller 100 may control the cooling fan 9 and the water pump 23 based on data detected by the data detector 110, thereby efficiently cooling the intercooler 4 and the electrical component 5.

In addition, by driving the cooling fan 9 and the water pump the 23 at a maximum duty and a maximum RPM, among the requested driving RPMs of the water pump 23 and the operation duties of the cooling fan 9, based on the detected air temperature and the temperature of the electrical component 5, a control method of a cooling system for a hybrid vehicle according to an embodiment can enable more efficient cooling of the electrical component 5 and the intercooler 4, thereby improving the performance and efficiency of the entire system.

According to an embodiment, a control method of a cooling system for a hybrid vehicle is for cooling a cooling system of a hybrid vehicle (see FIG. 1), which includes the engine cooling apparatus 10 and the electrical component cooling apparatus 20, and in which the intercooler provided in the engine 3 is provided on the branch line 25 connected to the second line 21 and disposed in parallel with the electrical component 5 through the branch line 25. As shown in FIG. 3, the control method may include procedure (A), procedure (B), and procedure (C).

In an embodiment, in the procedure (A), the controller 100 may convert the requested RPMs of the water pump 23 and the operation duties of the cooling fan 9 based on data detected from the data detector 110 during starting and operation of the vehicle.

The procedure (A) may include the following steps.

At step S1, in a state that the vehicle is started (e.g., turned on), the user may begin to drive the vehicle.

In such a state, at step S2, the controller 100 may detect the temperature of the air supplied to the intercooler 4 or the temperature of the second coolant introduced into the intercooler 4 and the temperature of the electrical component 5 based on data detected from the data detector 110.

At step S3, then, the controller 100 may convert the requested RPMs of the water pump 23 and the operation duties of the cooling fan 9 based on the air temperature detected from the data detector 110 or the temperature of the second coolant and the temperature of the electrical component 5.

In an embodiment, in the procedure (B), a maximum requested RPM and a maximum operation duty may be selected from among the requested RPMs of the water pump 23 and the operation duties of the cooling fan 9 converted through the procedure (A), and the controller 100 may drive the water pump 23 and the cooling fan 9 may be driven based on thereon.

The procedure (B) may include the following steps.

When the procedure (A) is completed, the controller 100 may compare the data converted at the step S3 with the map of the operation duty of the cooling fan 9 and the requested RPM of the water pump 23 according to a predetermined temperature, and the maximum requested RPM and the maximum operation duty among the converted requested RPMs of the water pump 23 and the operation duties of the cooling fan 9 may be selected, respectively, at step S4.

At step S5, then, the controller 100 may drive the water pump 23 at the maximum requested RPM selected at the step S4, and may drive the cooling fan 9 at the maximum operation duty.

In addition, in the procedure (C), the controller 100 may determine whether the air temperature or the temperature of the second coolant and the temperature of the electrical component 5 are in a range of upper and lower allowable temperatures based on predetermined reference temperatures and data detected in real time from the data detector 110, and thereby control the RPM of the water pump 23 and the operation duty of the cooling fan 9.

The procedure (C) may include the following steps.

When the procedure (B) is completed, the controller 100 may determine whether the air temperature or the temperature of the second coolant and a temperature of the electrical component 23 are in the range of upper and lower allowable temperatures based on data detected in real time from the data detector 110, at step S6.

Here, the range of upper and lower allowable temperatures may be set such that the air temperature, the second coolant temperature, and the temperature of the electrical component 23—detected by the air temperature sensor 112, the electrical component temperature sensor 114, and the coolant temperature sensor 116, respectively—are each greater than or equal to a predetermined minimum reference temperature and less than a predetermined maximum reference temperature.

The range of upper and lower allowable temperatures may be set according to the air temperature detected from a predetermined data map or the temperature of the second coolant and the temperature of the electrical component 23.

When it is determined that the air temperature or the temperature of the second coolant and the temperature of the electrical component 23 are in the range of upper and lower allowable temperatures (i.e., the condition is satisfied) at the step S6 of determining whether the air temperature or the temperature of the second coolant and the temperature of the electrical component 23 are in the range of upper and lower allowable temperatures, the controller 100 may maintain the RPM of the water pump 23 and the operation duty of the cooling fan 9 that are currently being driven and terminate the control, respectively, at step S7.

On the other hand, when it is determined that the air temperature or the temperature of the second coolant and the temperature of the electrical component 23 are not in the range of upper and lower allowable temperatures (i.e., when the condition is not satisfied) at the step S6 of determining whether the air temperature or the temperature of the second coolant and the temperature of the electrical component 23 are in the range of upper and lower allowable temperatures, the controller 100 may return to the step S3 of converting the requested RPM of the water pump 23 and the operation duty of the cooling fan 9 based on the detected air temperature or the temperature of the second coolant and the temperature of the electrical component 23.

While performing the above steps, the controller 100 may efficiently control the duty of the cooling fan 9 and the RPM of the water pump 23 according to the temperature of the air supplied to the intercooler 4 or the temperature of the second coolant and the temperature of the electrical component 23.

Therefore, as described above, according to a cooling system for a hybrid vehicle and a control method thereof according to an embodiment, by cooling the intercooler 4 by using the electrical component cooling apparatus 20 configured to cool the electrical component 5, the number of components can be reduced and the overall system may be simplified.

In addition, the present disclosure can facilitate securing a space for installing the cooling system through streamlining of the entire system, and by reducing the size and weight of the cooling module 7 mounted on the front of the vehicle, space utilization may be improved.

In addition, the present disclosure can simplify the layout of connection pipes for flowing the coolant inside the narrow engine compartment.

In addition, according to the present disclosure, by setting inner diameters of the second line 21 and the branch line 25 to be different from each other without employing a valve for controlling the flow direction and flow rate of the coolant, the flow rate of the coolant may be controlled by using the flow resistance of the coolant.

In addition, by driving the water pump 23 and the cooling fan 9 at the maximum RPM and a maximum duty among the requested driving RPMs of the water pump 23 and the operation duties of the cooling fan 9 based on the detected air temperature or the temperature of the second coolant and the temperature of the electrical component 23, the present disclosure can enable more efficient cooling of the intercooler 4 and the electrical component 5, and can improve the performance and efficiency of the entire system.

While the present disclosure has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

DESCRIPTION OF SYMBOLS

• • 3: engine
  • 4: intercooler
  • 5: electrical component
  • 7: cooling module
  • 9: cooling fan
  • 10: engine cooling apparatus
  • 11: first line
  • 12: first radiator
  • 20: electrical component cooling apparatus
  • 21: second line
  • 22: second radiator
  • 23: water pump
  • 25: branch line
  • 27: reservoir tank
  • 100: controller
  • 110: data detector
  • 112: the air temperature sensor
  • 114: electrical component temperature sensor
  • 116: the coolant temperature sensor