In-wheel motor cooling apparatus and method

Abstract

The in-wheel motor cooling apparatus and method may include: a brake data calculation section configured to calculate a brake severity related to brake data of a brake device in a traveling state; a motor temperature measuring section configured to measure a temperature and a temperature change of the in-wheel motor in a traveling completion state; a drive controller configured to start driving the water pump in a traveling completion state when the brake severity and the temperature change are higher than a predetermined criterion; and a cooling flow control section configured to determine a cooling flow rate of the water pump in real time based on a temperature of the in-wheel motor when driving of the water pump is started.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10–2023–0102810 filed in the Korean Intellectual Property Office on August 7, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an in-wheel motor cooling apparatus and method, and more particularly, to an in-wheel motor cooling apparatus and method capable of preventing the in-wheel motor from being deteriorated. Background Art

[0004] In vehicles driven by electricity, such as hybrid vehicles, fuel cell vehicles, and electric vehicles, an in-wheel drive system is a system in which a small individual motor is mounted on each wheel, rather than using a large single motor, to generate electricity and drive each wheel.

[0005] The in-wheel drive system is equipped with a separate motor for each wheel (hereinafter referred to as an in-wheel motor), and the drive system is simpler than a car equipped with a large drive motor. Therefore, a larger vehicle interior space can be obtained. Moreover, the rotation of the wheel can be directly controlled, providing an advantage of being able to omit a complex power transmission device.

[0006] In this way, since powertrain components can be omitted, high efficiency and high performance can be obtained. In other words, by directly mounting the in-wheel motor on each wheel, sufficient driving force can be ensured by reducing power waste. By maximizing the power distribution to each in-wheel motor when driving and recollecting the braking energy from regenerative braking, an improvement in electrical efficiency can be obtained.

[0007] The brakes within the in-wheel motor play an important role in slowing or stopping the vehicle. When the brake system operates the brakes, a large amount of heat is generated and this heat must be removed from the interior of the in-wheel motor. If this heat is not properly managed, it may cause performance degradation of the components, shorten the life, and in severe cases, may cause failure of the components or even fire of the in-wheel motor 100.

[0008] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure. Therefore, the Background section may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0009] The present disclosure provides an in-wheel motor cooling apparatus and method capable of cooling heat transferred to the in-wheel motor by radiation from a braking device during an ignition-off state or condition.

[0010] Embodiments provide an in-wheel motor cooling apparatus and method capable of monitoring a temperature change of an in-wheel motor in a flameout state and controlling driving of a water pump according to a braking severity of a braking device before the flameout state.

[0011] The in-wheel motor cooling device may include a braking data calculation unit configured to calculate a braking severity related to braking data of a braking device in a driving state; a motor temperature measurement unit configured to measure the temperature and temperature change of an in-wheel motor in a state where the wheel is in a state of driving completion; a drive controller configured to start driving a water pump in a state where driving is completed when the braking severity and temperature change are higher than predetermined standards; and a cooling flow control unit configured to determine the cooling flow of the water pump in real time based on the temperature of the in-wheel motor when starting to drive the water pump.

[0012] The driving state may be an ignition-on state in which the vehicle is started, and the driving completion state may be an ignition-off state in which the vehicle is turned off.

[0013] The brake data calculation section may be configured to calculate the brake severity based on brake data of the vehicle, the brake data including brake hydraulic pressure in an ignition state, a brake cycle, a travel speed, and a heat dissipation coefficient of the vehicle.

[0014] The cooling flow control portion may determine the cooling flow of the water pump to be the emergency cooling flow as the maximum flow of the water pump when the temperature of the in-wheel motor is higher than the emergency cooling temperature, which may be lower than a predetermined motor management temperature of the in-wheel motor by a first temperature difference.

[0015] When the temperature of the in-wheel motor is greater than a basic cooling temperature and less than or equal to an emergency cooling temperature, the cooling flow control unit may determine the cooling flow of the water pump to be a basic cooling flow less than the emergency cooling flow, wherein the basic cooling temperature is less than the motor management temperature by a second temperature difference.

[0016] When the basic cooling flow rate during the running of the vehicle is less than the cooling flow rate, the cooling flow control portion may adjust the basic cooling flow rate to be equal to the cooling flow rate during the running.

[0017] After starting to drive the water pump, the drive controller may stop driving the water pump when the temperature of the in-wheel motor is less than or equal to the base cooling temperature.

[0018] The in-wheel motor cooling method may include calculating the braking severity of the vehicle during driving by an in-wheel motor cooling device when the vehicle is turned off; measuring the temperature and temperature change of the in-wheel motor of the vehicle in a flameout state with the vehicle turned off by the in-wheel motor cooling device; in the flameout mode, controlling the driving of a water pump by the in-wheel motor cooling device based on the calculated braking severity and the measured temperature change of the in-wheel motor; and when starting to drive the water pump, controlling the cooling flow of the water pump in real time based on the temperature of the in-wheel motor by the in-wheel motor cooling device.

[0019] Calculating the braking severity may include calculating the braking energy using braking data of the vehicle, the braking data including a brake hydraulic pressure, a braking cycle, a driving speed, and a heat dissipation coefficient in a driving state of an ignition of the vehicle.

[0020] Controlling the driving of the water pump may include starting to drive the water pump if the braking energy is higher than a predetermined specific standard and a temperature variation of the in-wheel motor is greater than a predetermined specific standard.

[0021] Controlling the cooling flow may include determining the cooling flow of the water pump to be the emergency cooling flow as a maximum flow of the water pump when the temperature of the in-wheel motor is greater than an emergency cooling temperature, wherein the emergency cooling temperature is lower than a predetermined motor management temperature of the in-wheel motor by a first temperature difference.

[0022] Controlling the cooling flow may further include determining the cooling flow of the water pump to be a basic cooling flow that is less than the emergency cooling flow when the temperature of the in-wheel motor is greater than a basic cooling temperature and less than or equal to an emergency cooling temperature, wherein the basic cooling temperature is less than the motor management temperature by a second temperature difference.

[0023] Determining the cooling flow rate as the base cooling flow rate may include adjusting the base cooling flow rate to be equal to the cooling flow rate at ignition when the base cooling flow rate is less than the cooling flow rate at ignition of the vehicle.

[0024] Controlling the driving of the water pump may further include stopping driving the water pump after starting driving the water pump when the temperature of the in-wheel motor is less than or equal to the base cooling temperature.

[0025] The in-wheel motor cooling method may include calculating the temperature rise of the in-wheel motor based on the initial temperature of the braking device when the vehicle is in a flameout state; calculating the maximum achieved temperature of the in-wheel motor based on the initial temperature and the temperature rise after the in-wheel motor is in a flameout state; calculating the cooling target temperature of the in-wheel motor based on the difference between the maximum achieved temperature and the limit temperature of the in-wheel motor; measuring the real-time temperature of the in-wheel motor and driving a water pump until the real-time temperature is lower than the cooling target temperature.

[0026] The amount of temperature rise of the in-wheel motor may be proportional to the initial temperature of the brake device.

[0027] The driving of the water pump may include calculating a temperature difference between an ambient air temperature and a cooling target temperature and controlling a cooling flow rate of the water pump based on the calculated temperature difference.

[0028] Controlling the cooling flow may include determining the cooling flow of the water pump as a basic cooling flow when the temperature difference between the cooling target temperature and the ambient air temperature is greater than a specific standard; and determining the cooling flow as an emergency cooling flow when the temperature difference is less than the specific standard, wherein the emergency cooling flow is greater than the basic cooling flow.

[0029] Calculating the cooling target temperature may include, when calculating a difference between the maximum reaching temperature and the limit temperature, determining a resultant value obtained by subtracting the difference from an initial temperature of the in-wheel motor as the cooling target temperature.

[0030] The in-wheel motor cooling method may further include maintaining a maximum achieved temperature of the in-wheel motor below a limit temperature of the in-wheel motor.

[0031] According to the in-wheel motor cooling apparatus and method of the embodiment, heat transferred to the in-wheel motor by radiation from the braking device can be cooled during the engine-off state.

[0032] According to the in-wheel motor cooling apparatus and method of the embodiment, the temperature change of the in-wheel motor may be monitored in the light-off state, and the driving of the water pump may be controlled according to the braking severity of the braking device before the light-off state. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is an exploded perspective view showing an in-wheel motor according to an embodiment.

[0034] Figure 2 is a diagram illustrating a cooling system of an in-wheel motor according to an embodiment.

[0035] Figure 3 is a graph showing the effect of the in-wheel motor cooling apparatus according to the embodiment.

[0036] Figure 4 is a block diagram of an in-wheel motor cooling apparatus according to an embodiment.

[0037] Figure 5 is a flowchart of an in-wheel motor cooling method according to an embodiment.

[0038] Figure 6 is a flow chart of an in-wheel motor cooling method according to another embodiment.

[0039] Figure 7 A diagram for explaining a method of cooling an in-wheel motor is shown. DETAILED DESCRIPTION

[0040] The embodiments of the present disclosure are described more fully below with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the disclosed embodiments. As those of ordinary skill in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. In order to clarify the present disclosure, parts not related to the description are omitted, and the same elements or equivalents are represented by the same reference numerals throughout the specification.

[0041] 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 the element but not the exclusion of any other element. Terms including common numbers such as first and second are used to describe various constituent elements, but the constituent elements are not limited by the terms. These terms are only used to distinguish one component from other components.

[0042] In addition, the terms "unit", "section" or "part", "device" and "module" in the specification refer to a unit that processes at least one function or operation, which can be implemented by hardware, software or a combination thereof. When a part, device, element, etc. of the present disclosure is described as having a purpose or performing an operation, function, etc., the part, device, or element should be considered as "configured to" meet the purpose or perform the operation or function in this article.

[0043] Hereinafter, embodiments of the present disclosure are described with reference to the accompanying drawings.

[0044] Figure 1 is an exploded perspective view showing the in-wheel motor 100 according to the embodiment.

[0045] Figure 1 An exploded view of a wheel including a wheel 10, a tire 20, and an in-wheel motor 100 is shown. According to an embodiment, the wheel may include the in-wheel motor 100 inside the wheel 10. The in-wheel motor 100 may include a braking device 170.

[0046] The wheel 10 is mainly made of metal and rotates around a central axis. The wheel 10 is used to support the tire, reduce the impact received from the road, and support the weight of the vehicle. The tire 20 surrounds the outer side of the wheel 10 and is mainly made of rubber and steel wire. The tire 20 can control the direction and speed of the vehicle using friction with the road surface. The tire 20 absorbs vibrations from the road surface to provide a comfortable driving environment and improve vehicle safety.

[0047] Reference Figure 1The in-wheel motor 100 includes a rotor 110 , a stator 120 , a bearing 130 , a capacitor ring 140 , a power electronic device 150 , a protective cover 160 , and a brake device 170 . The brake device 170 includes a caliper 171 and a disc 172 .

[0048] The in-wheel motor 100 is an electric vehicle driving system that drives the wheels by directly installing a motor on each wheel. Unlike the conventional driving method using an internal combustion engine and a transmission, efficient energy transfer can be achieved because the wheels and the motor are directly connected.

[0049] The rotor 110 is a component that rotates by receiving power from the in-wheel motor 100. The rotor 110 is used to transmit the rotational force of the motor to the wheel. The rotation of the rotor 110 is the main means of converting power into mechanical energy. The stator 120 is a fixed component of the in-wheel motor 100 and is generally made of a coil or a magnet. When electric energy passes through the stator 120, a magnetic field is generated, and the magnetic field causes the rotor 110 to rotate.

[0050] The bearing 130 is a component that enables the shaft to achieve rotation between the rotor 110 and the stator 120 and supports internal components to rotate smoothly. The bearing 130 allows the rotor 110 to move smoothly and reduces friction to minimize power loss.

[0051] When the in-wheel motor 100 is started, the capacitor ring 140 provides the required additional current. When the in-wheel motor 100 starts to rotate normally, the capacitor ring 140 can be automatically disconnected from the circuit. In other words, the capacitor ring 140 provides additional current for supporting the stator 120.

[0052] The power electronics 150 is an electronic device for power conversion and control. The power electronics 150 can control the power of the in-wheel motor 100, adjust the speed and torque, regenerate braking energy, and effectively manage the battery. For example, the power electronics 150 may include an inverter, a converter, a DC-DC converter, and a control system.

[0053] The inverter converts the direct current (DC) power provided by the battery into alternating current (AC) power to drive the motor. The inverter can control the speed of the motor. The converter converts the voltage of the battery to provide the required voltage. The converter provides the voltage required to operate the inverter or to power other electronic systems of the vehicle. The DC-DC converter provides the necessary voltage for other electronic systems of the vehicle. The control system controls the torque, speed, direction, etc. of the in-wheel motor 100. In addition, the battery management system (BMS) can monitor the charge state of the battery and protect the battery when necessary. The power electronics 150 in the in-wheel motor 100 are responsible for power conversion and control, as well as motor control.

[0054] The protective cover 160 protects the internal components of the in-wheel motor 100. The protective cover 160 protects the inside of the in-wheel motor 100 from external factors such as dust, water, and stones, and can prevent the internal components from being damaged due to absorbing the impact when the in-wheel motor 100 receives a direct impact. Generally, the protective cover 160 is made of a strong metal or plastic and is designed to perfectly match the shape and size of the in-wheel motor 100. For example, the protective cover 160 can completely cover the in-wheel motor 100 and may be equipped with a cooling function such as a vent or a cooling fin.

[0055] In the case of the in-wheel motor 100, although the mechanical brake device may exist in the form of a disc brake directly connected to the wheel, the in-wheel motor 100 itself may perform regenerative braking. The brake device 170 may exist inside the wheel of the vehicle or the in-wheel motor 100. The brake device 170 may include a caliper 171 and a disc 172.

[0056] The caliper 171 is a main component of the brake device and is used to reduce or stop the rotation of the wheel by applying pressure to the brake pads on the disc.

[0057] The disc 172 is a metal plate that rotates with the wheel, and the brake pad reduces or stops the rotation of the wheel by pressing against the disc with the caliper 171. The brake device 170 included inside the in-wheel motor 100 can operate with regenerative braking to improve the braking performance and energy efficiency of the vehicle.

[0058] When the brake device 170 inside the in-wheel motor 100 operates, a large amount of heat is generated, and if the heat is not properly managed, according to the degradation phenomenon, performance degradation, shortened life of components, and in severe cases, failure of components or even fire of the in-wheel motor 100 may be caused. Hereinafter, a cooling system, a cooling device, and a cooling method are proposed to prevent failure of the in-wheel motor 100 due to such degradation phenomenon.

[0059] Figure 2 is a diagram illustrating a cooling system of an in-wheel motor according to an embodiment.

[0060] Reference Figure 2, the cooling system SY of the in-wheel motor 100 may include a first system SY1 and a second system SY2. The first system SY1 includes the in-wheel motor 100, a cooling device 300 and a water pump WP1. The cooling device 300 may be referred to as an in-wheel motor cooling device 300 and is responsible for cooling the in-wheel motor 100. For example, the in-wheel motor cooling device 300 is configured to measure the temperature of the in-wheel motor 100 and control the water pump WP1. The water pump WP1 may supply cooling fluid at a cooling flow rate suitable for the in-wheel motor 100 under the control of the in-wheel motor cooling device 300. Here, the in-wheel motor 100 may mean a concept for including all components such as a rotor and a stator except the braking device 170, for distinguishing the scope of the term.

[0061] The second system SY2 includes a brake device 170, a brake fluid 400 and a fluid pump WP2. When the piston moves, the brake fluid 400 transmits pressure. The pressure can be transmitted to the brake pads and discs or drums of the brake system through the brake fluid 400. The brake fluid 400 is a mixture mainly based on water and ethanol, and has a high boiling point, a low freezing point and sufficient hydraulic properties. The brake fluid 400 will not evaporate even at a particularly high temperature and has the characteristic of preventing corrosion in the system. The fluid pump WP2 supplies the brake fluid 400 to the brake device 170.

[0062] In the first system SY1, in the ignition state of starting the vehicle due to the in-wheel motor 100 being driven, the in-wheel motor 100 can be cooled in real time by the in-wheel motor cooling device 300. In addition, during the operation of the in-wheel motor 100, the heat of the in-wheel motor 100 can be cooled by the surrounding air.

[0063] However, in the flameout state where the vehicle is turned off because the in-wheel motor 100 is not operating, the in-wheel motor cooling device 300 itself does not work. In addition, because the vehicle is not driven, the heat of the in-wheel motor 100 cannot be cooled by air. Therefore, the heat generated in the in-wheel motor 100 needs to be cooled in the flameout state of the vehicle. Specifically, in the flameout state, what needs to be prevented is the temperature increase of the in-wheel motor 100 due to the heat transferred from the adjacent braking device 170 by radiation, rather than the heat generated by the operation of the in-wheel motor 100.

[0064] In an embodiment, in the ignition off state, the cooling system SY of the in-wheel motor 100 may cool the in-wheel motor 100 in consideration of heat energy transferred through interaction between the first system SY1 and the second system SY2. For example, the in-wheel motor cooling device 300 of the first system SY1 may control the water pump WP1 in consideration of radiant heat transferred from the brake device 170 of the second system SY2 to the in-wheel motor 100.

[0065] The in-wheel motor cooling device 300 may calculate the brake data of the brake device 170 collected in the ignition state of the vehicle. The in-wheel motor cooling device 300 may also determine whether to drive the water pump WP1 in consideration of the calculated brake data and the temperature change of the in-wheel motor 100 in the ignition-off state. If the in-wheel motor cooling device 300 has determined to drive the water pump WP1 in the ignition-off state based on the brake data and the temperature change of the in-wheel motor 100, the cooling flow rate of the water pump WP1 is variably determined based on the real-time temperature of the in-wheel motor 100.

[0066] Figure 3 is a graph showing the effect of the in-wheel motor cooling device according to the embodiment. Figure 2 Explain together.

[0067] exist Figure 3 In the conventional case, the in-wheel motor cooling device 300 does not operate in the ignition-off state in which the in-wheel motor 100 does not operate. Therefore, the cooling flow rate of the water pump WP1 is maintained at 0 liters per minute (LPM). Figure 2 As described, in the ignition off state, the in-wheel motor cooling device 300 can also operate based on the braking data and the temperature change of the in-wheel motor 100 in the ignition off state. In other words, when the braking data and the temperature change of the in-wheel motor 100 meet certain standards, the in-wheel motor cooling device 300 drives the water pump WP1.

[0068] When the in-wheel motor cooling device 300 starts operating, it can control the cooling flow of the water pump WP1 based on the real-time temperature of the in-wheel motor 100 on a basic or emergency basis. For example, assuming that the motor management temperature is 100°C, when the current temperature of the in-wheel motor 100 is greater than 90°C, the in-wheel motor cooling device 300 can control the water pump WP1 at an emergency cooling flow. When the current temperature of the in-wheel motor 100 is greater than 75°C and less than or equal to 90°C, the in-wheel motor cooling device 300 can also control the water pump WP1 at a basic cooling flow. For example, when the maximum cooling flow of the water pump WP1 is 15LPM, the emergency cooling flow can be equal to the maximum cooling flow, and the basic cooling flow can be 10LPM. Refer to Figure 4 and Figure 5 This is explained in detail.

[0069] Figure 4 is a block diagram of an in-wheel motor cooling apparatus according to an embodiment.

[0070] Reference Figure 4 The in-wheel motor cooling device 300 includes a braking data calculation section 310 , a motor temperature measurement section 320 , a drive controller 330 , and a cooling flow control section 340 .

[0071] Hereinafter, the driving state may refer to the key-on state in which the vehicle is started, and the driving completion state may refer to the key-off state in which the vehicle is turned off. The driving of the vehicle occurs in the key-on state. However, the in-wheel motor cooling device according to the embodiment may be operated in the key-off state.

[0072] The braking data calculation section 310 may calculate the braking severity associated with the braking data of the braking device in the driving state. The braking severity may be measurement data indicating how many times the braking of the vehicle has occurred in the driving state or how hard or severe the braking of the vehicle is.

[0073] When in the ignition state, according to the braking that occurs during the driving of the vehicle, the braking severity can be calculated based on the braking data. For example, the braking severity can be calculated based on various braking data of the vehicle collected from the braking device, the braking data including braking force, braking distance, braking hydraulic pressure, braking cycle, driving speed, transmission efficiency, and heat dissipation coefficient.

[0074] When the vehicle is turned off, the braking data calculation part 310 may calculate the braking severity based on the braking data collected according to the braking that has occurred while driving in the ignition state.

[0075] The motor temperature measuring part 320 can measure the temperature and temperature change of the in-wheel motor 100 in the driving completion state. In other words, the motor temperature measuring part 320 can measure the temperature change of the in-wheel motor 100 and the real-time temperature in the ignition-off state.

[0076] In the driving completion state, when the braking severity and temperature variation of the in-wheel motor 100 are a predetermined standard or higher, the driving controller 330 may start driving the water pump WP1 (refer to Figure 2 ).

[0077] When the vehicle is turned off (i.e., turned off or in a key-off state), the drive controller 330 receives the braking severity from the brake data calculation unit 310 and the temperature change of the in-wheel motor 100 from the motor temperature measurement unit 320, and can drive the water pump WP1 when they are both above a predetermined reference value.

[0078] When the water pump WP1 starts to be driven, the cooling flow control section 340 may determine the cooling flow rate of the water pump WP1 in real time based on the temperature of the in-wheel motor 100. The cooling flow control section 340 may control the cooling flow rate of the water pump WP1 based on the current temperature of the in-wheel motor 100 measured in real time by the motor temperature measurement section 320. For example, according to a preset standard, when it is determined that the temperature of the in-wheel motor 100 is close to the motor management temperature, the cooling flow control section 340 may increase the cooling flow rate, and when it is determined that the temperature of the in-wheel motor 100 is not close to the motor management temperature, the cooling flow control section 340 may reduce the cooling flow rate.

[0079] Figure 5 is a flowchart of an in-wheel motor cooling method according to an embodiment. Figure 5 The in-wheel motor cooling method can be performed by the in-wheel motor cooling device 300. Figure 4 Explain this.

[0080] exist Figure 5 In step S510, when the vehicle is turned off, the in-wheel motor cooling device 300 may calculate the braking severity of the vehicle during driving. The braking severity of the vehicle may be calculated based on various braking data of the vehicle collected from the braking device during driving, the braking data including braking force, braking distance, braking hydraulic pressure, braking cycle, driving speed, transmission efficiency, and heat dissipation coefficient.

[0081] Since the brake device 170 (ref. Figure 1 ) may rise to more than about 500°C, so it may be difficult to directly calculate its temperature. Therefore, the in-wheel motor cooling device 300 may calculate the braking severity based on the braking data, and then may estimate the heat generated at the braking device. In addition, if only the brake hydraulic operation logic is used, it is difficult to distinguish between stopping and driving, it is difficult to distinguish the amount of deceleration, and it is difficult to determine the influence of braking heat energy, so the in-wheel motor cooling device 300 is set by reference to the defined braking severity.

[0082] For example, the braking severity may be calculated as braking energy (i.e., rate or work, calories, BTU's, kw, hp, etc.) based on various braking data of the vehicle. In this context, braking energy may refer to the heat generated during the process of converting kinetic energy into thermal energy by the braking device of the vehicle in order to reduce the speed. For example, the braking energy may be calculated from the braking cycle, the driving speed, the transmission efficiency, the brake hydraulic pressure, and various braking factors.

[0083] In step S510, the in-wheel motor cooling device 300 may measure the temperature and temperature change of the in-wheel motor 100 in the ignition off state. Because the temperature of the in-wheel motor 100 may be about 50° C. to 140° C. under normal circumstances, the motor temperature measuring unit 320 (refer to Figure 4) can directly measure temperature.

[0084] The in-wheel motor cooling device 300 may control the driving of the water pump WP1 based on the severity of braking and the temperature change of the in-wheel motor 100 in the flameout state. In step S520, when the braking energy is higher than a predetermined specific standard and the temperature change of the in-wheel motor 100 is higher than a specific standard, the in-wheel motor cooling device 300 may start driving the water pump WP1. For example, when the braking energy in calories at flameout exceeds 300 kcal and the temperature change of the in-wheel motor 100 exceeds 0.1°C / second, the in-wheel motor cooling device 300 may drive the water pump WP1 to start cooling the in-wheel motor 100. On the contrary, when the braking energy and temperature change of the in-wheel motor 100 are a specific standard or lower, the in-wheel motor cooling device 300 does not drive the water pump.

[0085] The in-wheel motor cooling apparatus 300 may control the cooling flow rate of the water pump in real time based on the temperature of the in-wheel motor 100 .

[0086] The in-wheel motor cooling device 300 may measure the current temperature of the in-wheel motor 100 through the motor temperature measuring section 320. The in-wheel motor cooling device 300 may obtain an emergency cooling temperature based on a motor management temperature established in the in-wheel motor 100. In one embodiment, the emergency cooling temperature may be determined as a temperature that is less than the motor management temperature of the in-wheel motor 100 by a first temperature difference. For example, when the motor management temperature is 100°C, the in-wheel motor cooling device 300 may set the emergency cooling temperature to 90°C. In other words, the first temperature difference may be approximately 10°C.

[0087] In step S530 , the in-wheel motor cooling apparatus 300 may compare the current temperature of the in-wheel motor 100 with the emergency cooling temperature.

[0088] In step S531, when the temperature of the in-wheel motor 100 is greater than the emergency cooling temperature, the in-wheel motor cooling device 300 may determine the cooling flow rate of the water pump WP1 as the emergency cooling flow rate as the maximum flow rate of the water pump WP1 through the cooling flow control portion 340. For example, when the maximum flow rate of the water pump WP1 is 15 LPM, the in-wheel motor cooling device 300 may determine the emergency cooling flow rate as 15 LPM. When the temperature of the in-wheel motor 100 is greater than the emergency cooling temperature, the in-wheel motor cooling device 300 may drive the water pump WP1 at a predetermined maximum flow rate, thereby giving priority to protecting the in-wheel motor 100, with little regard for efficiency.

[0089] The in-wheel motor cooling device 300 may set a basic cooling temperature based on the motor management temperature. The in-wheel motor cooling device 300 may determine the basic cooling temperature as a temperature that is lower than the motor management temperature by a second temperature difference. For example, when the motor management temperature is 100°C, the basic cooling temperature may be set to 75°C. In other words, the second temperature difference may be 25°C. It is understood that the second temperature difference is greater than the first temperature difference.

[0090] At step S540 , the in-wheel motor cooling apparatus 300 may compare the current temperature of the in-wheel motor 100 with the basic cooling temperature.

[0091] In step S550, when the temperature of the in-wheel motor 100 is greater than the basic cooling temperature and less than or equal to the emergency cooling temperature, the in-wheel motor cooling device 300 can determine the cooling flow of the water pump WP1 as the basic cooling flow through the cooling flow control unit 340, and can compare the cooling flow and the basic cooling flow under the ignition state.

[0092] In step S551, as a result of comparing the cooling flow rate in the ignition state and the basic cooling flow rate, when the basic cooling flow rate is greater than the cooling flow rate in the ignition state, the in-wheel motor cooling device 300 may maintain the cooling flow rate at the basic cooling flow rate. The basic cooling flow rate may be less than the emergency cooling flow rate. For example, when the maximum flow rate of the water pump WP1 is 15LPM, the basic cooling flow rate may be 10LPM to 12LPM. The in-wheel motor cooling device 300 may determine the optimal flow rate as the basic cooling flow rate in view of the optimization of electric power consumption and the protection of the in-wheel motor 100.

[0093] In step S552, when the basic cooling flow rate is less than the cooling flow rate in the ignition state, the in-wheel motor cooling device 300 may adjust the basic cooling flow rate to be the same as the cooling flow rate in the ignition state. That is, when the cooling flow rate in the ignition state is less than the cooling flow rate in the ignition state, the in-wheel motor cooling device 300 is judged to be inefficient, and the cooling flow rate in the ignition state may be maintained at least at the cooling flow rate in the ignition state.

[0094] In step S560, after starting to drive the water pump WP1, when the temperature of the in-wheel motor 100 becomes less than the basic cooling temperature, the in-wheel motor cooling device 300 may stop driving the water pump WP1. The in-wheel motor cooling device according to the embodiment operates to protect the in-wheel motor 100. Therefore, when it is determined that the temperature of the in-wheel motor 100 is sufficiently different from the motor management temperature for heat transfer from the braking device, the logic is terminated and the driving of the water pump WP1 may be stopped. In other words, in consideration of minimization of power consumption, NVH (noise, vibration, harshness), and the environment of the occupant, the current logic of the in-wheel motor cooling method may be stopped as early as possible.

[0095] Figure 6 is a flow chart of an in-wheel motor cooling method according to another embodiment. Figure 7 A diagram for explaining the in-wheel motor cooling method is shown. The in-wheel motor cooling method according to the embodiment can be performed by the in-wheel motor cooling device 300 (refer to Figure 2 )implement.

[0096] Figure 6 The in-wheel motor cooling method can estimate the temperature increase amount of the in-wheel motor 100 by the temperature of the brake device, and cool the in-wheel motor based on the temperature increase amount. The in-wheel motor cooling method assumes that the temperature increase amount of the in-wheel motor 100 is determined by the initial temperature of the brake device, and has nothing to do with the initial temperature of the in-wheel motor 100 in the ignition-off state. The in-wheel motor cooling method directly calculates how much heat is transferred from the disc of the brake device to the in-wheel motor after the vehicle is turned off, and can determine the cooling flow rate of the water pump WP1 based on this.

[0097] exist Figure 6 and Figure 7 In step S610, the vehicle is in an ignition-off state, and in step S620, the in-wheel motor cooling device 300 measures the initial temperature T of the brake device. D_init and the initial temperature T of the in-wheel motor 100 M.init Braking device 170 (reference Figure 1 ) may be the initial temperature of disk 172 (reference Figure 1 The initial temperature T of the brake device 170 D_init The disk temperature can be measured by the disk temperature occurring through the thermal equivalent model 720 at the time point when the vehicle is turned off (ie, turned off). In the first graph 710, the disk temperature can be naturally cooled after the vehicle is turned off. The initial temperature T of the in-wheel motor 100 M.init The temperature of the in-wheel motor 100 when the engine is turned off can be calculated through CAN communication.

[0098] In step S630, the in-wheel motor cooling device 300 may be based on the braking device T D_init The temperature rise ΔT of the in-wheel motor 100 is calculated from the initial temperature M.rise When referring to the thermal equivalent model 720 , the temperature rise ΔT of the in-wheel motor 100 M.rise Can be compared with the initial temperature T of the brake device D_init The amount of heat transfer due to the temperature change of the in-wheel motor 100 (eg, 20° C. to 150° C.) is significantly lower than the amount of heat transfer of the disk (which may rise to about 500° C. or more).

[0099] The in-wheel motor cooling device 300 may be based on the initial temperature T M.init and the temperature increase ΔT of the in-wheel motor 100 after the engine is turned off.M.rise Calculate the maximum temperature T of the in-wheel motor 100 M.init +△T M.rise In the second graph 730 , the maximum reached temperature T of the in-wheel motor 100 is M.init +△T M.rise The temperature T of the in-wheel motor 100 may be higher than the limit temperature T M.max .

[0100] In step S640 , the in-wheel motor cooling device 300 may cool the in-wheel motor 100 based on the maximum reachable temperature and the limit temperature T M.max The difference (i.e., T M.init +△T M.rise -T M.max ) to calculate the cooling target temperature T of the in-wheel motor 100 M.target .

[0101] In an embodiment, the in-wheel motor cooling device 300 can cool the maximum reachable temperature T of the in-wheel motor 100. M.init +△T M.rise With limit temperature T M.max The difference between M.init +△T M.rise -T M.max ) is determined as the temperature reduction amount T required for the in-wheel motor 100 M.cool The in-wheel motor cooling device 300 can cool the in-wheel motor 100 by cooling the initial temperature T M.init Subtract the required temperature reduction T M.cool The obtained value T M.init -T M.cool Determined as the cooling target temperature T M.target The limit temperature T of the in-wheel motor 100 M.max It may be the limit temperature of the winding of the in-wheel motor 100 .

[0102] In the third graph 740 , the in-wheel motor cooling device 300 may cool the temperature of the in-wheel motor 100 to a temperature reduction amount ΔT required by the in-wheel motor 100 . M.cool Set the cooling target temperature T M.target After that, the in-wheel motor cooling device 300 may be managed so that the maximum reachable temperature T of the in-wheel motor 100 is M.init +△T M.rise The temperature rise does not exceed the limit temperature T of the in-wheel motor 100. M.max .

[0103] In steps S650 to S670 , the in-wheel motor cooling device 300 may measure the real-time temperature T of the in-wheel motor 100 . M And it can drive the water pump WP1 until the real-time temperature T Mbecomes lower than the cooling target temperature T M.target .

[0104] In step S650, the in-wheel motor cooling device 300 may compare the current temperature T M and the cooling target temperature T of the in-wheel motor 100 M.target When the current temperature T of the in-wheel motor 100 M Less than the cooling target temperature T M.target , the in-wheel motor cooling device 300 ends the present logic and does not drive the water pump. However, in steps S660, S661 and S662, when the current temperature T of the in-wheel motor 100 is M Greater than or equal to the cooling target temperature T M.target When the in-wheel motor cooling device 300 can calculate the ambient air temperature and the cooling target temperature T M.target The temperature difference between the in-wheel motor 100 and the in-wheel motor 100 is calculated, and the cooling flow rate of the water pump WP1 is controlled based on the calculated temperature difference. The ambient air temperature may refer to the atmospheric temperature. For example, the ambient air temperature may be approximately 45°C. The in-wheel motor cooling device 300 may control the cooling flow rate of the water pump WP1 to reduce the current temperature T of the in-wheel motor 100 to 45°C. M Reduce to cooling target temperature T M.target .

[0105] In an embodiment, in steps S660, S661 and S662, when the ambient air temperature and the cooling target temperature T M.target When the temperature difference between the two is greater than a certain standard, the in-wheel motor cooling apparatus 300 may determine the cooling flow rate of the water pump WP1 as the basic cooling flow rate. When the temperature difference is less than or equal to a certain standard, the in-wheel motor cooling apparatus 300 may also determine the cooling flow rate as the emergency cooling flow rate.

[0106] The emergency cooling flow may have a cooling flow greater than the basic cooling flow. For example, the emergency cooling flow may be equal to the maximum cooling flow of the water pump WP1. In consideration of power efficiency, the basic cooling flow may be appropriately determined within a range lower than the maximum cooling flow of the water pump. For example, when the maximum cooling flow of the water pump WP1 is 15 LPM, the emergency cooling flow is 15 LPM, and the basic cooling flow may be 10 to 12 LPM. The basic cooling flow may be at least greater than or equal to the cooling flow in the ignition state.

[0107] At step S661 , when the temperature difference between the ambient air temperature and the cooling target temperature is greater than 20° C., the in-wheel motor cooling apparatus 300 may perform cooling in the first mode. The first mode may correspond to a case where the cooling flow rate of the water pump WP1 is determined as a basic cooling flow rate.

[0108] At step S662 , when the temperature difference between the ambient air temperature and the cooling target temperature is less than 20° C., the in-wheel motor cooling apparatus 300 may perform cooling in the first mode. The second mode may correspond to a case where the cooling flow rate of the water pump WP1 is determined as an emergency cooling flow rate.

[0109] According to the in-wheel motor cooling method, when the current sensor temperature T of the in-wheel motor 100 is M Lower than the cooling target temperature T M.target When the in-wheel motor cooling device 300 turns off the pump. On the contrary, when the sensor temperature TM of the in-wheel motor 100 is higher than the cooling target temperature T M.target When the in-wheel motor cooling device 300 cools the sensor temperature of the in-wheel motor 100 to the cooling target temperature T M.target .

[0110] In the above process, in the in-wheel motor cooling method, when the weather is hot and the ambient air temperature is greater than the cooling target temperature T M.target When the difference between the ambient air temperature and the cooling target temperature T is small (for example, 20° C. or less), the in-wheel motor is strongly cooled in the second mode because the influence of convection cooling is small. M.target When the difference between φ and φ is high (eg, above 20° C.), the water pump is weakly driven in the first mode to cool the in-wheel motor because the surrounding air can obtain a large cooling effect.

[0111] Although the technical concept of the present disclosure has been described in conjunction with what are currently considered to be practical embodiments, it should be understood that the present disclosure is not limited to the disclosed embodiments. Instead, the present disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0112] <Description of the symbol>

[0113] 100 In-wheel motor

[0114] 170 Braking device

[0115] 300 In-wheel motor cooling equipment

[0116] 310 Braking data calculation unit

[0117] 320 Motor temperature measurement unit

[0118] 330 Drive Controller

[0119] 340 Cooling flow control unit.

Claims

1. An in-wheel motor cooling device, comprising: a braking data calculation unit configured to calculate a braking severity associated with braking data of a braking device in a driving state; a motor temperature measuring unit configured to measure the temperature and temperature change of the in-wheel motor in a driving completion state; a drive controller configured to start driving a water pump in the driving completion state when the braking severity and the temperature change are higher than a predetermined standard; as well as The cooling flow control unit is configured to determine a cooling flow rate of the water pump in real time based on a temperature of the in-wheel motor when driving of the water pump is started.

2. The in-wheel motor cooling device according to claim 1, wherein: The driving state is an ignition-on state in which the vehicle is started, and wherein the driving completion state is an ignition-off state in which the vehicle is turned off.

3. The in-wheel motor cooling device according to claim 2, wherein: The brake data calculation section is configured to calculate the brake severity based on the brake data of the vehicle, the brake data including a brake hydraulic pressure in the ignition state, a brake cycle, a travel speed, and a heat dissipation coefficient of the vehicle.

4. The in-wheel motor cooling device according to claim 1, wherein: When the temperature of the in-wheel motor is higher than the emergency cooling temperature, the cooling flow control unit determines the cooling flow rate of the water pump to be the emergency cooling flow rate which is the maximum flow rate of the water pump; and The emergency cooling temperature is lower than a predetermined motor management temperature of the in-wheel motor by a first temperature difference.

5. The in-wheel motor cooling device according to claim 4, wherein: When the temperature of the in-wheel motor is greater than a basic cooling temperature and less than or equal to the emergency cooling temperature, the cooling flow control unit determines the cooling flow rate of the water pump to be a basic cooling flow rate that is less than the emergency cooling flow rate; and The basic cooling temperature is lower than the motor management temperature by a second temperature difference.

6. The in-wheel motor cooling device according to claim 5, wherein: When the basic cooling flow rate is smaller than a cooling flow rate during running of the vehicle, the cooling flow control portion adjusts the basic cooling flow rate to be equal to the cooling flow rate during the running.

7. The in-wheel motor cooling device according to claim 6, wherein: After starting to drive the water pump, the drive controller stops driving the water pump when the temperature of the in-wheel motor is less than or equal to the basic cooling temperature.

8. A method for cooling an in-wheel motor, comprising: calculating a braking severity of the vehicle during travel by an in-wheel motor cooling device when the vehicle is turned off; measuring, by the in-wheel motor cooling device, a temperature and a temperature change of the in-wheel motor of the vehicle in an ignition-off state in which the vehicle is turned off; In an engine-off state, driving of a water pump is controlled by the in-wheel motor cooling device based on the calculated braking severity and the measured temperature change of the in-wheel motor; and When the water pump starts to be driven, the cooling flow rate of the water pump is controlled in real time based on the temperature of the in-wheel motor by the in-wheel motor cooling device.

9. The in-wheel motor cooling method according to claim 8, wherein: Calculating the braking severity further includes: The braking energy is calculated using braking data of the vehicle, the braking data including a braking hydraulic pressure, a braking cycle, a driving speed, and a heat dissipation coefficient in a driving state with the ignition of the vehicle on.

10. The in-wheel motor cooling method according to claim 9, wherein: Controlling the driving of the water pump further comprises: If the braking energy is higher than a predetermined specific standard and a temperature change of the in-wheel motor is greater than a predetermined specific standard, the water pump starts to be driven.

11. The in-wheel motor cooling method according to claim 10, wherein: Controlling the cooling flow further includes: When the temperature of the in-wheel motor is greater than the emergency cooling temperature, the cooling flow rate of the water pump is determined to be the emergency cooling flow rate which is the maximum flow rate of the water pump. The emergency cooling temperature is lower than a predetermined motor management temperature of the in-wheel motor by a first temperature difference.

12. The in-wheel motor cooling method according to claim 11, wherein: Controlling the cooling flow further includes: When the temperature of the in-wheel motor is greater than a basic cooling temperature and less than or equal to the emergency cooling temperature, the cooling flow rate of the water pump is determined to be a basic cooling flow rate that is less than the emergency cooling flow rate, The basic cooling temperature is lower than the motor management temperature by a second temperature difference.

13. The in-wheel motor cooling method according to claim 12, wherein: Determining the cooling flow rate as the basic cooling flow rate further includes: When the basic cooling flow rate is less than the cooling flow rate when the vehicle is ignited, the basic cooling flow rate is adjusted to be equal to the cooling flow rate when the vehicle is ignited.

14. The in-wheel motor cooling method according to claim 13, wherein: Controlling the driving of the water pump further comprises: After the water pump starts to be driven, when the temperature of the in-wheel motor is less than or equal to the basic cooling temperature, the driving of the water pump is stopped.

15. A method for cooling an in-wheel motor, wherein: include: When the vehicle is in an ignition-off state, the temperature increase of the in-wheel motor is calculated based on the initial temperature of the brake device; calculating a maximum reached temperature of the in-wheel motor based on the initial temperature and the temperature increase amount after the in-wheel motor is turned off; calculating a cooling target temperature of the in-wheel motor based on a difference between the maximum achieved temperature and a limit temperature of the in-wheel motor; and A real-time temperature of the in-wheel motor is measured and a water pump is driven until the real-time temperature is lower than the cooling target temperature.

16. The in-wheel motor cooling method according to claim 15, wherein: The temperature increase amount of the in-wheel motor is proportional to an initial temperature of the brake device.

17. The in-wheel motor cooling method according to claim 15, wherein: Driving the water pump further comprises: calculating a temperature difference between an ambient air temperature and the cooling target temperature; and A cooling flow rate of the water pump is controlled based on the calculated temperature difference.

18. The in-wheel motor cooling method according to claim 17, wherein: Controlling the cooling flow further includes: When the temperature difference between the cooling target temperature and the ambient air temperature is greater than a specific standard, determining the cooling flow rate of the water pump as a basic cooling flow rate; and When the temperature difference is less than the specific standard, the cooling flow rate is determined as an emergency cooling flow rate, Wherein, the emergency cooling flow rate is greater than the basic cooling flow rate.

19. The in-wheel motor cooling method according to claim 18, wherein: Calculating the cooling target temperature further includes: When a difference between the maximum reached temperature and the limit temperature is calculated, a resultant value obtained by subtracting the difference from the initial temperature of the in-wheel motor is determined as the cooling target temperature.

20. The in-wheel motor cooling method according to claim 15, further comprising: The maximum achieved temperature of the in-wheel motor is maintained below a limit temperature of the in-wheel motor.

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