Electric oil pump control method for vehicle

Abstract

The present invention relates to a method for controlling an electric oil pump of a vehicle, the method comprising the following steps: determining whether the vehicle has entered a slope; when it is determined that the vehicle has entered the slope, determining whether a drive motor of the vehicle is in one or more overheat conditions; when it is determined that the vehicle is in an overheat condition, determining whether the duration of the overheat condition exceeds a preset reference time; and when the duration of the overheat condition exceeds the preset reference time, supplying pulsation to an RPM input of the electric oil pump.

Description

Technical Field

[0001] The present invention relates to a method for controlling an electric oil pump for a vehicle. More particularly, the present invention relates to a method for controlling an electric oil pump for an environmentally friendly vehicle, wherein the pump can more effectively cool the vehicle's drive motor, particularly when the vehicle is traveling on a slope. Background Art

[0002] "Eco-friendly vehicles (EVs)" are a general term for vehicles equipped with rechargeable high-voltage, large-capacity batteries, including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell electric vehicles (FCEVs), etc.

[0003] The drive motor plays an important role in driving environmentally friendly vehicles. Due to losses such as heat, wind, and sound, the drive motor has an efficiency of approximately 90%. When the temperature of the drive motor rises, heat losses occur, accounting for approximately 25% of the total losses. If the drive motor is heated above a threshold temperature, which serves as the upper limit of the drive motor's stable operating temperature, the drive motor overheats and may cause the coils around the drive motor's stator to burn or the permanent magnets in the rotor to demagnetize. Therefore, an appropriate cooling system is provided in the drive motor to ensure that the drive motor operates below the threshold temperature.

[0004] Depending on the type of cooling fluid, the drive motor can be cooled by water, air or oil. Moreover, the drive motor can be cooled directly or indirectly based on whether there is contact or not. Recently, as the importance of the cooling capacity of the drive motor has increased with the increasing demand for high-performance drive motors, direct cooling using oil is increasingly used to cool the drive motor. The oil used as the coolant is pumped by an electric oil pump (EOP). Since the EOP logic that determines the oil supply amount is directly related to the performance of the motor cooling system, it is crucial to develop an EOP logic that can determine the optimal oil supply amount in each case.

[0005] The oil supply of the EOP depends on the temperature measured by the temperature sensor. The temperature sensor can be located on the coil of the drive motor or at the oil supply port of the EOP. The temperature sensor of the drive motor is set at the area where the coil is least cooled. Figure 1 , a weak cooling area generally appears in the portion of the coil C located at the six o'clock position of the drive motor as indicated by H1.

[0006] When an increase in the drive motor's temperature, the oil's temperature, or the amount of temperature change over time is detected, the EOP is controlled to increase the oil supply to improve cooling performance. Due to the high viscosity of the oil, the oil pumped by the EOP flows in a clumped state along the predetermined path L1 (denoted by the dotted line). Area H1, which is not on path L1, becomes a high-temperature area. Therefore, a temperature sensor T is positioned at the 6 o'clock position of the drive motor and measures a temperature representative of the steps taken to protect the drive motor at that position.

[0007] When the vehicle is traveling on a flat road, it is preferable to measure the drive motor temperature in the six o'clock area, indicated by H1. However, when the vehicle is traveling on a slope, such as a downhill or uphill slope, the drive motor's weak cooling area may change. In other words, the drive motor's weak cooling area may not be located in the six o'clock area, H1. Therefore, when the vehicle is traveling on a slope, it is necessary to take measures to improve the cooling performance in the weak cooling area of ​​the drive motor.

[0008] The information included in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an admission or any form of suggestion that this information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0009] Various aspects of the present invention are directed to providing a method for controlling an electric oil pump of a vehicle, which is capable of improving cooling performance of a poorly cooled area in a drive motor.

[0010] Various aspects of the present invention are directed to providing a method for controlling an electric oil pump of a vehicle, which can improve the driving performance of the vehicle.

[0011] Another object of the present invention is to provide a method for controlling an electric oil pump of a vehicle, which can ensure the safety of a drive motor by preventing damage and demagnetization caused by overheating that occurs in the drive motor when the vehicle is traveling on a slope.

[0012] Another object of the present invention is to provide a method for controlling an electric oil pump of a vehicle, which can reduce the cost of the vehicle.

[0013] It will be understood that the objects of the present invention are not limited to the above objects, and other objects not mentioned above may be understood from the following description by those skilled in the art to which various exemplary embodiments of the present invention pertain.

[0014] Features of the present invention for achieving the above-mentioned objects and for performing the characteristic functions of the present invention are described below.

[0015] According to various aspects of the present invention, a method for controlling an electric oil pump of a vehicle includes: determining whether the vehicle has entered a slope having a gradient greater than a predetermined gradient; when it is determined that the vehicle has entered a slope having a gradient greater than the predetermined gradient, determining whether a drive motor of the vehicle is in one or more overheat conditions; when it is determined that the vehicle is in an overheat condition, determining whether a duration of the overheat condition exceeds a preset reference time; and when the duration of the overheat condition exceeds the preset reference time, supplying pulsation to an RPM input of the electric oil pump.

[0016] According to various exemplary embodiments of the present invention, in an EOP control method, the EOP is controlled to supply cooling oil at a variable, rather than fixed, oil supply rate. Specifically, the EOP oil supply rate varies over time in a sinusoidal or square wave pattern, altering the oil flow path and causing pulsation. This ensures that oil is supplied to the entire drive motor area. This control method improves cooling performance even in weakly cooled areas of the drive motor.

[0017] Furthermore, according to various exemplary embodiments of the present invention, the method may prevent the drive motor from being derating by improving cooling performance in a weak cooling area of ​​the drive motor, thereby ensuring greater stability of the vehicle and improving driving performance.

[0018] The method according to various exemplary embodiments of the present invention eliminates the risk of local overheating damage to the coils of the drive motor and demagnetization of the permanent magnets when the weak cooling area changes while the vehicle is traveling on a slope, thereby improving vehicle safety.

[0019] Furthermore, the method according to various exemplary embodiments of the present invention can prevent overheating damage to the drive motor when the vehicle is traveling on a slope without providing an additional temperature sensor in a changed weak cooling area, thereby reducing vehicle costs.

[0020] The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly recognized by those skilled in the art from the following description.

[0021] The methods and apparatus of the present invention have other features and advantages that will be apparent from or set forth in more detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain certain principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a diagram exemplarily showing a flow path of a driving motor and cooling oil of a vehicle;

[0023] Figure 2Ais a view exemplarily showing the position of a drive motor in a vehicle when the vehicle is traveling on an uphill slope;

[0024] Figure 2B yes Figure 2A An enlarged view of the portion indicated by Q1 in FIG.

[0025] Figure 3A is a view exemplarily showing the position of a drive motor in a vehicle when the vehicle is traveling on a downhill slope;

[0026] Figure 3B It is shown as an example Figure 3A An enlarged view of the portion indicated by Q2 in FIG.

[0027] Figure 4 is a diagram exemplarily showing waveforms of drive currents of respective phases in a Hill-Hold state;

[0028] Figure 5 is a block diagram illustrating a structure of an oil cooling system for an electric oil pump control method according to various exemplary embodiments of the present invention;

[0029] Figure 6 is a block diagram illustrating a cooling process of a drive motor describing an electric oil pump control method according to various exemplary embodiments of the present invention;

[0030] Figure 7 is a flowchart illustrating an electric oil pump control method according to various exemplary embodiments of the present invention;

[0031] Figure 8 is a flowchart illustrating an electric oil pump control method according to various exemplary embodiments of the present invention;

[0032] Figure 9 is a flowchart illustrating an electric oil pump control method according to various exemplary embodiments of the present invention;

[0033] Figure 10 is a flowchart illustrating an electric oil pump control method according to various exemplary embodiments of the present invention;

[0034] Figure 11 is a graph showing an EOP revolution (RPM) pulsation graph and a response curve graph of an input according to various exemplary embodiments of the present invention; and

[0035] Figure 12 2 is a graph showing an EOP revolution (RPM) pulsation graph and a response curve graph according to various exemplary embodiments of the present invention.

[0036] It should be understood that the drawings are not necessarily drawn to scale and present a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as incorporated herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

[0037] In the drawings, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0038] Reference will now be made in detail to various embodiments of the present invention, examples of which are shown in the accompanying drawings and described below. Although the present invention will be described in conjunction with exemplary embodiments thereof, it will be understood that this description is not intended to limit the invention to those exemplary embodiments. On the other hand, the present invention is intended to cover not only the exemplary embodiments of the present invention, but also various alternative embodiments, modifications, equivalent embodiments, and other embodiments that may be included within the spirit and scope of the present invention as defined by the appended claims.

[0039] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific structures or functions described in the exemplary embodiments of the present invention are for illustrative purposes only. The embodiments according to the concepts of the present invention can be implemented in various forms, and it is understood that the embodiments are not to be construed as being limited to the exemplary embodiments described in the exemplary embodiments, but rather include all modified embodiments, equivalent embodiments, or alternative embodiments included in the spirit and scope of the present invention.

[0040] It will be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements may not be limited by these terms. These terms are merely used to distinguish one element from another. For example, the first element discussed below may be referred to as the second element without departing from the teachings of the present invention. Similarly, the second element may also be referred to as the first element.

[0041] It will be understood that when an element is referred to as being "coupled" or "connected" to another element, the element may be directly coupled or connected to the other element, or there may be intervening elements between the two elements. Conversely, it will be understood that when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements. Other expressions such as "between," "directly between," "adjacent to," or "directly adjacent to" that explain a relationship between elements may be interpreted in the same manner.

[0042] Throughout the specification, the same reference numerals represent the same components. Meanwhile, the terms used herein are only used to describe various exemplary embodiments and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms. It will be further understood that the terms "comprises", "comprising", "having", etc., when used in exemplary embodiments, specify the presence of stated components, steps, operations, or elements, but do not exclude the presence or addition of one or more other components, steps, operations, or elements.

[0043] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0044] As previously described in the background section, it is preferable to use the temperature measured in the six o'clock area H1, where cooling is weak, as the basis for determining the oil supply amount of the electric oil pump (EOP). However, since the weak cooling area may change when the vehicle is traveling on a slope, the base temperature used for determining the oil supply amount needs to be corrected.

[0045] When the vehicle is on a slope, the flow path of the oil changes according to the slope angle, and the position of the weak cooling area changes. In the case of an uphill vehicle, since the flow path of the oil changes from path L1 to path L2, the weak cooling area may change from area H1 to area H2 (see Figure 2A and Figure 2B ). In the case of a downhill slope, the flow path of the oil changes from the path L1 to the path L3, and the weak cooling area can be changed from the area H1 to the area H3 (see Figure 3A and Figure 3B ).

[0046] In these cases, the temperature sensor T located in the six o'clock area H1 cannot measure the temperature of the highest temperature area H2 or area H3 in the drive motor 100. Then, during driving on a slope, at a high current operating point or in a Hill-Hold situation, the overheat protection logic designed for the drive motor 100 cannot operate normally, and the drive motor 100 may overheat and be damaged. Figure 4 As shown, Hill-Hold refers to a state where a fixed current is applied to each phase coil in the drive motor 100 .

[0047] According to various exemplary embodiments of the present invention, a method for controlling an electric oil pump of a vehicle is provided that can improve cooling of a weak cooling area that changes depending on driving conditions (eg, when the vehicle is driving on a slope).

[0048] Reference Figure 5 and Figure 6According to various exemplary embodiments of the present invention, an oil cooling system (OS) of an environmentally friendly vehicle operates in combination with a water cooling system (WS).

[0049] The oil cooling system (OS) includes a temperature sensor 10, and the temperature sensor 10 includes a drive motor temperature sensor 12 and an oil temperature sensor 14. As previously mentioned, the drive motor temperature sensor 12 is provided in a region where cooling is weak in the drive motor 100, for example, at the six o'clock position in the drive motor 100. The oil temperature sensor 14 may include a sensor that measures the temperature T of the oil before the oil enters the drive motor 100. bf The oil temperature sensor 14 measures the temperature T of the oil returning to the EOP 30 after circulating through the drive motor. af The oil temperature sensor 14. A negative temperature coefficient (NTC) type sensor or a positive temperature coefficient (PTC) type sensor can be used as the temperature sensor 10. The NTC type sensor and the PTC type sensor are based on the principle that resistance changes with temperature.

[0050] The controller 50 receives a measurement from the temperature sensor 10 and determines the oil flow rate and oil injection pressure based on the measured temperature. In other words, the controller 50 determines the RPM of the EOP 30 based on the temperature received from the temperature sensor 10. The controller 50 has an RPM map 52 for the EOP 30. The RPM map 52 is pre-configured based on variables including the temperature of the drive motor 100, the temperature of the oil, and changes in temperature over time. The controller 50 determines a specific RPM value for the measured temperature from the RPM map 52 and transmits this specific RPM value to the EOP 30. In turn, the EOP 30 rotates at the specific RPM value based on the command from the controller 50. The EOP 30 includes a control unit 32 that causes the pump 34 to rotate at the specific RPM value instructed by the controller 50. The control unit 32 can transmit information about the actual RPM value and any malfunctions of the EOP 30 to the controller 50.

[0051] The oil pumped by the EOP 30 is cooled by exchanging heat with low temperature cooling water in the heat exchanger 70. Cooled to a temperature T bf The oil is injected from the cooling pipe 110 to the driving motor 100 by the pressure of the EOP 30 , thereby cooling the driving motor 100 .

[0052] After cooling the drive motor 100, the oil is removed from its own impurities by the oil filter 92 included in the speed reducer 90. The filtered oil is returned to the EOP 30, and the oil is repeatedly circulated as described above.

[0053] According to the EOP RPM graph 52, the EOP 30 is configured to drive the EOP at a higher RPM as the temperature of the oil or the drive motor 100 increases, so that a larger amount of oil is supplied to the drive motor 100. As the amount of oil supplied by the EOP 30 increases, the contact area between the oil and the heat-generating parts of the drive motor 100 increases, thereby cooling the drive motor 100 through faster oil circulation.

[0054] When the vehicle is traveling on a slope, the weak cooling area may change from H1 to H2 or H3. Therefore, the present invention includes additional EOP control logic to provide sufficient cooling performance in the changed weak cooling area. The additional EOP control logic may be included in the EOP RPM map 52.

[0055] Reference Figure 7 , an electric oil pump control method according to various exemplary embodiments of the present invention will be described. First, the method determines whether a predetermined condition is satisfied to determine whether to adopt an additional EOP operation.

[0056] According to various exemplary embodiments of the present invention, one of the predetermined conditions may be a condition that the vehicle is traveling on a slope. The controller 50 determines whether the vehicle is on a slope (step S20) to determine whether an additional EOP operation is required.

[0057] Whether the vehicle is on a slope can be detected by measuring the vehicle's tilt angle, that is, the angle of inclination between the vehicle and the horizontal. Alternatively, the determination of whether the vehicle is on a slope can be made using a known method such as an acceleration sensor. When the tilt angle measured by the acceleration sensor or the like exceeds a preset reference tilt angle, the controller 50 determines that the vehicle has entered a slope.

[0058] When it is determined that the vehicle is traveling on a slope, the controller is configured to determine whether the drive motor 100 is in an overheating condition (step S40). In the exemplary embodiment, the term "overheating condition" or "potential overheating condition" is defined as a condition required to introduce the control method according to each exemplary embodiment of the present invention.

[0059] Reference Figure 8 According to various exemplary embodiments of the present invention, the overheat condition includes a state in which the drive current flowing through the drive motor 100 exceeds a preset reference current (step S140). The controller 50 receives the current drive current of the drive motor 100 and compares the current drive current with the reference current to determine whether the drive motor of the vehicle is in an overheat condition.

[0060] For example, if the driving motor corresponds to a three-phase driving motor including three-phase coils u, v, and w, the overheating condition includes a state in which a maximum current value of the three-phase current exceeds a preset reference current.

[0061] like Figure 9 As shown, according to various exemplary embodiments of the present invention, whether the drive motor of the vehicle is in an overheating condition can be detected by comparing the current speed of the vehicle and the current torque of the vehicle. When the current speed of the vehicle is less than a specific speed and the current torque of the vehicle exceeds the expected torque predicted at the current speed of the vehicle, it can be determined that the drive motor 100 is in an overheating condition (step S240). The controller 50 can determine whether the drive motor of the vehicle is in an overheating condition by comparing the current torque of the vehicle with the expected torque corresponding to the current speed of the vehicle.

[0062] like Figure 10 As shown, according to various exemplary embodiments of the present invention, the controller 50 detects whether the position of the coil with the maximum phase current among the coils wound around the drive motor is consistent with the position of the weak cooling area caused by the vehicle on the slope (step S340). When the two positions are consistent with each other, the drive motor is considered to be very likely to be in an overheating condition. In the current case, the preset reference time to be described later can be reduced. The reduced reference time is reset to a reference time that is less than the initially set reference time and greater than 0. For example, the reference time can be half of the initially set reference time.

[0063] Refer again Figure 7 or Figure 9 When the vehicle's drive motor is determined to be overheated, the controller 50 further determines whether the duration of the overheat condition exceeds a preset reference time. In other words, the controller 50 determines whether the duration of the overheat condition exceeds the preset reference time (step S60). For example, the controller 50 determines whether the drive current of the drive motor 100 exceeds the reference current for a period of time exceeding the preset reference time. Alternatively, the controller 50 detects the duration of a state in which the vehicle's current speed is less than a specific speed and the vehicle's current torque exceeds the expected torque at the specific speed.

[0064] According to various exemplary embodiments of the present invention, any time period is defined as a cycle, and a reference number of cycles is set for repetition. For example, a cycle may be set to 10 milliseconds, and the reference number of cycles may be set to 300. In this case, if an overheat condition persists for more than 3 seconds, it is determined that additional EOP control is required.

[0065] When the duration of the overheat condition is detected to exceed the reference time, the controller 50 changes the RPM of the EOP 30 (step S80 ). That is, pulsation is applied to the RPM input of the EOP according to the EOPRPM map 52 .

[0066] like Figure 11 As shown in Equation 1, according to various exemplary embodiments of the present invention, the pulsation is input to the RPM of the EOP 30 in the form of a sine wave.

[0067] [Equation 1]

[0068] RPM=RPM 当前 +αsin(βT)

[0069] Wherein α and β are set according to the current RPM, the temperature of the drive motor 100 and the temperature of the oil, and T is time. Here, α is the amplitude of the sine curve. β is the frequency of the sine curve and can be used to change the period of the sine curve. In an exemplary embodiment of the present invention, α can be set based on parameters including the current RPM of the EOP, the current temperature of the drive motor 100 and the current temperature of the oil. In the same way, β can be set based on parameters including the current RPM of the EOP, the current temperature of the drive motor 100 and the current temperature of the oil. For example, the amplitude α can be increased, the frequency β can be increased, or both can be increased.

[0070] The sine wave can be input continuously or intermittently. When a sinusoidal pulse is input, the oil flow path can be changed due to the fluctuation of the oil, and the oil can intermittently reach the entire area of ​​the drive motor 100, including the weak cooling area of ​​the drive motor. In other words, the overheating problem caused by the weak cooling area due to the fixed oil flow path can be solved.

[0071] According to various exemplary embodiments of the present invention, Figure 12 As shown in Equation 2, the pulsation is input to the RPM of the EOP 30 in the form of a square wave or a pulse wave.

[0072] [Equation 2]

[0073] RPM=RPM 当前 +C

[0074] Where C is 1 or 0.

[0075] For example, C = 1 is applied for one second and C = 0 is applied for three seconds. This cycle can be repeated one or more times.

[0076] When the input pulsation is a square wave, the oil flow path can be changed due to the supply of pulsation. At the same time, since there is no need to calculate the sine wave, the control logic can be simplified.

[0077] Effects provided by the electric oil pump control method of a vehicle according to various exemplary embodiments of the present invention will be described below.

[0078] Conventionally, in high-current or Hill-Hold situations, the RPM of the EOP is set according to the temperature, and the EOP is controlled based on the set RPM and temperature, without considering changes in the weak cooling area within the drive motor. On the other hand, the present invention improves the cooling performance of the weak cooling area that changes when the vehicle operates on a slope by controlling the EOP to perform additional operational control. Therefore, the control method of the present invention can solve the problems of damage caused by local overheating in the weak cooling area of ​​the drive motor and demagnetization of the permanent magnets.

[0079] When the temperature of the drive motor rises, the EOP is controlled to increase the oil supply, thereby improving the cooling performance. Even in the current case, since the flow path of the oil in the drive motor is fixed and the oil falls due to gravity, a weak cooling area is formed in the lower part of the drive motor where the oil is difficult to reach. However, according to various exemplary embodiments of the present invention, since the flow rate of the EOP is changed by applying a changing value such as a sine wave, the oil supply is changed, and the flow path of the oil is changed, and pulsations occur in the oil flow, thereby forcing the oil to enter the weak cooling area. In other words, the cooling of the weak cooling area that occurs in the drive motor can be improved.

[0080] When a temperature sensor detects a temperature greater than or equal to a predetermined upper limit of an allowable temperature range during vehicle driving, derating is performed to prevent overheating of the vehicle and the drive motor. The present invention can prevent derating of the drive motor by improving cooling performance in a weak cooling area occurring in the drive motor, thereby ensuring stable driving performance of the vehicle.

[0081] In addition, the present invention can ensure the safety of the drive motor to prevent damage or demagnetization caused by overheating when the vehicle is traveling on a slope. In the case of conventional EOP control technology, when the weak cooling area in the drive motor is changed when the vehicle is traveling on a slope, the derating is delayed because the changed weak cooling area is not sufficiently cooled and the temperature of the weak cooling area cannot be detected, resulting in damage or demagnetization caused by overheating of the drive motor. However, according to various exemplary embodiments of the present invention, since the changed weak cooling area can be sufficiently cooled, the drive motor can be protected from overheating even in the event of a failure of the overheat protection derating logic.

[0082] To prevent damage caused by overheating in weak cooling areas that change when a vehicle travels on a slope, one approach is to install additional temperature sensors in the corresponding locations. However, this approach inevitably increases costs. According to various exemplary embodiments of the present invention, since additional temperature sensors are not required, advantages such as cost savings are achieved.

[0083] In addition, terms such as "controller," "control unit," "control device," or "control module" related to a control device refer to a hardware device that includes a memory and a processor, the processor being configured to execute one or more steps interpreted as an algorithmic structure. The memory stores the algorithmic steps, and the processor executes the algorithmic steps to perform one or more processes of the method according to various exemplary embodiments of the present invention. The control device according to an exemplary embodiment of the present invention can be implemented using a non-volatile memory and a processor, the non-volatile memory being configured to store data regarding algorithms for controlling the operation of various components of the vehicle or software commands for executing the algorithms, and the processor being configured to use data stored in the memory to perform the aforementioned operations. The memory and processor can be separate chips. Alternatively, the memory and processor can be integrated into a single chip. The processor can be implemented as one or more processors. The processor can include various logic circuits and arithmetic circuits, can process data according to a program provided from the memory, and can generate control signals based on the processing results.

[0084] The control device may be at least one microprocessor operated by a predetermined program, and the predetermined program may include a series of commands for executing the methods included in the aforementioned various exemplary embodiments of the present invention.

[0085] The aforementioned invention may also be implemented as computer-readable code on a computer-readable recording medium. The computer-readable recording medium is any data storage device that can store data that can then be read by a computer system. Examples of computer-readable recording media include hard disk drives (HDDs), solid-state disks (SSDs), silicon disk drives (SDDs), read-only memories (ROMs), random-access memories (RAMs), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and the like, as well as implementations such as carrier waves (e.g., transmission via the Internet).

[0086] In various exemplary embodiments of the present invention, each of the above-described operations may be performed by a control device, and the control device may be configured by a plurality of control devices or an integrated single control device.

[0087] In various exemplary embodiments of the present invention, the control device may be implemented in the form of hardware or software, or may be implemented in a combination of hardware and software.

[0088] For ease of explanation and accurate definition in the appended claims, the terms "upper," "lower," "inner," "outer," "up," "lower," "upward," "downward," "front," "back," "rear," "inner," "outer," "inwardly," "outwardly," "inside," "outer," "inner," "external," "forward," and "rearward" are used to describe features of the exemplary embodiments shown in the drawings with reference to their positions. It will be further understood that the term "connect" or its derivatives refers to both direct and indirect connections.

[0089] Furthermore, the term "fixedly connected" means that fixedly connected members always rotate at the same speed. Furthermore, the term "selectively connectable" means that "when the selectively connectable members are not engaged with each other, the selectively connectable members rotate individually; when the selectively connectable members are engaged with each other, the selectively connectable members rotate at the same speed; and when at least one of the selectively connectable members is a fixed member and the remaining selectively connectable members are engaged to the fixed member, the selectively connectable members are fixed."

[0090] The foregoing description of specific exemplary embodiments of the present invention has been given for the purpose of illustration and description. The foregoing description is not intended to be exhaustive of the invention or to limit the invention to the precise form disclosed, and it is apparent that many modified embodiments and variant embodiments are possible in light of the above teachings. The exemplary embodiments are selected and described to explain certain principles of the present invention and their practical application, so that those skilled in the art can realize and utilize the various exemplary embodiments of the present invention and various alternative embodiments and modified embodiments thereof. The scope of the present invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A method for controlling an electric oil pump of a vehicle, the method comprising: The controller determines whether the vehicle has entered a ramp; When it is determined that the vehicle has entered the slope, the controller determines whether the drive motor of the vehicle is in at least one overheating condition; When it is determined that the vehicle is in the at least one overheating condition, the controller determines whether the duration of the at least one overheating condition exceeds a preset reference time; as well as When the duration of the at least one overheat condition exceeds the preset reference time, the controller supplies a pulse to the RPM input of the electric oil pump.

2. The method according to claim 1, wherein The pulse is input as a sine wave or a square wave.

3. The method according to claim 2, wherein: When the pulsation is input as the sine wave, the RPM is determined according to Equation 1, RPM = RPM 当前 +αsin(βT) Here, α and β are set according to the current RPM, the temperature of the drive motor, and the temperature of the oil in the oil cooling system including the electric oil pump and the drive motor.

4. The method according to claim 1, wherein When the inclination angle of the vehicle relative to the horizontal direction exceeds a preset reference inclination angle, the controller determines that the vehicle has entered the slope.

5. The method according to claim 1, wherein The at least one overheat condition includes a state where a driving current of the driving motor exceeds a preset reference current.

6. The method according to claim 5, wherein: When the drive motor is a three-phase motor, the at least one overheating condition includes a state where a maximum current value of the three-phase motor exceeds the preset reference current.

7. The method according to claim 1, wherein The at least one overheat condition is determined based on a current speed of the vehicle and a current torque of the vehicle.

8. The method according to claim 7, wherein: The at least one overheat condition includes a state where a current speed of the vehicle is less than a specific speed and a current torque of the vehicle exceeds an expected torque predicted based on the current speed of the vehicle.

9. The method according to claim 8, wherein The at least one overheating condition includes a state in which a position of a coil currently having a maximum phase current among coils wound around the drive motor coincides with a weak cooling area generated when the vehicle travels on the slope.

10. The method according to claim 9, wherein: When it is determined that the position of the coil currently having the maximum phase current coincides with the weak cooling area, the controller resets the preset reference time to a value that is smaller than the initially set reference time and greater than zero seconds.

11. The method according to claim 10, wherein: The preset reference time is reset to half of the initially set reference time.

12. The method according to claim 1, wherein The controller includes: processor; and A non-transitory storage medium having a program for executing the method recorded thereon, wherein the program is executed by the processor. 13 . A non-transitory computer-readable storage medium having recorded thereon a program for executing the method according to claim 1 .

14. An oil cooling system for a vehicle, the oil cooling system comprising: a drive motor fluidly connected to the heat exchanger; an oil pump fluidly connected to the heat exchanger; a drive motor temperature sensor, measuring the temperature of the drive motor, an oil temperature sensor, for measuring the temperature of the oil in the oil cooling system; as well as a controller electrically connected to the drive motor, the oil pump, the drive motor temperature sensor, and the oil temperature sensor, The controller determines whether the vehicle has entered a slope. When it is determined that the vehicle has entered the slope, the controller determines whether the drive motor of the vehicle is in at least one overheating condition, When it is determined that the vehicle is in the at least one overheating condition, the controller determines whether the duration of the at least one overheating condition exceeds a preset reference time, and When the duration of the at least one overheat condition exceeds the preset reference time, the controller supplies a pulse to the RPM input of the oil pump.

15. The oil cooling system according to claim 14, wherein: The pulse is input as a sine wave or a square wave.

16. The oil cooling system according to claim 14, wherein: When the inclination angle of the vehicle relative to the horizontal direction exceeds a preset reference inclination angle, the controller determines that the vehicle has entered the slope.

17. The oil cooling system according to claim 14, wherein: The at least one overheat condition includes a state where a driving current of the driving motor exceeds a preset reference current.

18. The oil cooling system according to claim 14, wherein: The at least one overheat condition includes a state where a current speed of the vehicle is less than a specific speed and a current torque of the vehicle exceeds an expected torque predicted based on the current speed of the vehicle.

19. The oil cooling system according to claim 18, wherein: The at least one overheating condition includes a state in which a position of a coil currently having a maximum phase current among coils wound around the drive motor coincides with a weak cooling area generated when the vehicle travels on the slope.

20. The oil cooling system according to claim 19, wherein: When it is determined that the position of the coil currently having the maximum phase current coincides with the weak cooling region, the controller resets the preset reference time to a value that is smaller than an initially set reference time and greater than zero seconds.

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