Vehicle

Abstract

This vehicle comprises: a battery; an oil-cooled motor generator driven by power from the battery; a pump for circulating oil to the oil-cooled motor generator; and a controller. The controller includes a processor and a memory storing an instruction executed by the processor. The processor is configured to control the pump according to the instruction such that, when the temperature of the battery is less than a predetermined first threshold at startup of the vehicle, the liquid surface of the oil in the oil-cooled motor generator is positioned in the gap between the rotor and the stator and the oil contacts both the rotor and the stator.

Description

vehicle

[0001] The present invention relates to a vehicle.

[0002] Vehicles that use electric power as a driving force, such as electric vehicles, may be equipped with a battery. For example, when starting a vehicle in a low-temperature environment, such as in winter, the battery temperature may be lower than the appropriate temperature. For example, Patent Document 1 discloses a motor control system that outputs a signal to an inverter to reduce the efficiency of the motor, thereby causing the motor to generate heat and warming up the battery quickly.

[0003] Japanese Patent Application Laid-Open No. 2020-110021

[0004] In such vehicles, there is a further need to quickly warm up the battery.

[0005] An object of the present invention is to provide a vehicle that can quickly warm up a battery.

[0006] In order to solve the above problem, a vehicle according to one embodiment of the present invention comprises: a battery; an oil-cooled motor-generator driven by power from the battery; a pump that circulates oil through the oil-cooled motor-generator; and a controller, wherein the controller includes a processor and a memory that stores instructions to be executed by the processor, and the processor is configured to execute the following instructions: when the temperature of the battery is below a predetermined first threshold when the vehicle is started, control the pump so that the oil level in the oil-cooled motor-generator is located in the gap between a rotor and a stator, and the oil contacts both the rotor and the stator.

[0007] According to the present invention, the battery can be warmed up quickly.

[0008] Fig. 1 is a schematic diagram showing a vehicle according to an embodiment. Fig. 2 is a schematic cross-sectional view showing a motor generator when the vehicle is stopped. Fig. 3 is a schematic cross-sectional view showing a motor generator when the vehicle is running normally. Fig. 4 is a schematic cross-sectional view showing a motor generator when the vehicle is started in a low-temperature environment. Fig. 5 is a graph showing the relationship between current phase angle and copper loss. Fig. 6 is a flowchart showing the operation of a vehicle according to an embodiment.

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is a schematic diagram showing a vehicle 10 according to an embodiment. The vehicle 10 is an automobile that uses electric power stored in a battery B as driving force. For example, the vehicle 10 may be a BEV (Battery Electric Vehicle). The vehicle 10 is not limited to a BEV, and may be any other automobile that uses electric power.

[0011] The vehicle 10 includes a battery B, an oil cooler C, a pump P, one or more oil-cooled motor-generators MG1, MG2, a circulation flow path L, and an ECU (controller) 50. The vehicle 10 may further include other components. In this embodiment, the "oil-cooled motor-generator" may simply be referred to as a "motor-generator."

[0012] Battery B is a secondary battery that can be charged and discharged, such as a lithium ion battery. Vehicle 10 includes a first sensor Se1 in battery B. First sensor Se1 is configured to measure the temperature of battery B. First sensor Se1 is communicably connected to ECU 50 and transmits the measured temperature to ECU 50.

[0013] The oil cooler C cools the oil flowing through the circulation flow path L.

[0014] The pump P circulates the oil in the circulation flow path L. The pump P is communicably connected to the ECU 50. The ECU 50 controls the pump P to adjust the flow rate of the oil flowing in the circulation flow path L.

[0015] The motor generators MG1 and MG2 are driven by electric power stored in a battery B. Furthermore, the motor generators MG1 and MG2 generate electric power during deceleration and store the electric power in the battery B. The motor generators MG1 and MG2 are communicably connected to an ECU 50. The ECU 50 controls the operation of the motor generators MG1 and MG2. Two motor generators MG1 and MG2 are shown in FIG. 1. The number of motor generators is not limited to two, and may be one or three or more.

[0016] The circulation flow path L circulates oil among the oil cooler C, the pump P, the motor generators MG1 and MG2, and the battery B. Note that other components, such as an inverter, may also be disposed on the circulation flow path L.

[0017] The circulation flow path L includes a flow path L1 connecting the pump P to the motor generators MG1 and MG2. In this embodiment, the flow path L1 branches into a flow path L11 connected to the motor generator MG1 and a flow path L12 connected to the motor generator MG2. In other embodiments, the flow paths L11 and L12 may extend independently from the pump P. The circulation flow path L includes a flow path L21 connecting the motor generator MG1 to the battery B. The circulation flow path L also includes a flow path L22 connecting the motor generator MG2 to the battery B. In this embodiment, the flow paths L21 and L22 are connected to the internal flow paths B1 and B2, which are independent of each other, within the battery B, respectively. The circulation flow path L includes a flow path L31 connecting the internal flow path B1 to the oil cooler C. The circulation flow path L also includes a flow path L32 connecting the internal flow path B2 to the oil cooler C. In this embodiment, the flow paths L31 and L32 merge into a single flow path L3 connected to the oil cooler C. In other embodiments, the flow path L31 and the flow path L32 may be connected independently to the oil cooler C. The circulation flow path L includes a bypass flow path L41 that connects the flow path L21 to the flow path L3, bypassing the battery B. The circulation flow path L also includes a bypass flow path L42 that connects the flow path L22 to the flow path L3, bypassing the battery B.

[0018] The circulation flow path L includes a first valve V1 on each of the flow paths L21 and L22. Specifically, the first valve V1 is provided at a position between the connection points to the bypass flow paths L41, L42 and the battery B. The first valve V1 is communicatively connected to the ECU 50. The ECU 50 controls the first valve V1 to adjust the flow rate of oil flowing from each of the motor generators MG1 and MG2 to the battery B.

[0019] The circulation flow path L includes a second valve V2 on each of the bypass flow path L41 and the bypass flow path L42. The second valve V2 is communicatively connected to the ECU 50. The ECU 50 controls the second valve V2 to adjust the flow rate of oil flowing through each of the bypass flow path L41 and the bypass flow path L42.

[0020] The vehicle 10 may further include a camera 60 capable of capturing images of the environment around the vehicle 10. The vehicle 10 may also include a navigation system 70. The camera 60 and the navigation system 70 are communicatively connected to the ECU 50. For example, the ECU 50 can detect road conditions around the vehicle 10 based on images from the camera 60. For example, the ECU 50 can acquire a planned route from the navigation system 70. For example, the ECU 50 can acquire the road conditions of the planned route by communicating with an external device.

[0021] The ECU (Electronic Control Unit) 50 controls part or all of the vehicle 10. The ECU 50 includes one or more processors 51 and one or more memories 52. The ECU 50 may further include other components. The components of the ECU 50 are communicatively connected to each other via a bus. For example, the processor 51 includes a CPU (Central Processing Unit). For example, the memory 52 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The memory 52 stores one or more programs to be executed by the processor 51. The operation of the ECU 50 described in the present disclosure is realized by the processor 51 executing instructions stored in the memory 52.

[0022] Fig. 2 is a schematic cross-sectional view showing the motor generator MG1 when the vehicle 10 is stopped. For simplification, components on the circulation flow path L other than the motor generator MG1 and the pump P are omitted from Fig. 2 and Figs. 3 and 4 described below. Furthermore, the motor generator MG2 has substantially the same configuration as the motor generator MG1 and operates in substantially the same manner. Therefore, the following description will focus on the motor generator MG1, and a description of the motor generator MG2 will be omitted.

[0023] For example, the motor generator MG1 includes a case 1, a stator 2, and a rotor 3. The motor generator MG1 may further include other components.

[0024] The case 1 houses the stator 2 and the rotor 3. The case 1 also stores oil F. The stator 2 is fixed to the case 1. The rotor 3 is rotatably supported by the case 1. A gap g is formed between the stator 2 and the rotor 3.

[0025] The motor generator MG1 includes an injection hole 11 connected to the flow path L11. For example, the injection hole 11 is provided in the upper part of the case 1. The injection hole 11 injects the oil F toward the stator 2 and the rotor 3.

[0026] For example, the motor generator MG1 may include a second sensor Se2. The second sensor Se2 is configured to detect whether the oil level SF of the oil F is higher than a predetermined level. For example, the second sensor Se2 may be a level sensor or a level switch. The second sensor Se2 is communicatively connected to the ECU 50 and transmits the detection result to the ECU 50. Note that the second sensor Se2 is not essential.

[0027] When the vehicle 10 is stopped, the oil F is stored in the case 1 so that the oil level SF is located within the gap g. Therefore, a portion of the gap g is filled with the oil F. The position of the oil level SF when the vehicle 10 is stopped is indicated by a height H1.

[0028] 3 is a schematic cross-sectional view showing the motor-generator MG1 when the vehicle 10 is running normally. When the vehicle 10 starts, the oil F is sent to the circulation flow path L by the pump P. Therefore, the oil F in the case 1 decreases. If oil F is present in the gap g during normal running, resistance due to friction occurs between the rotor 3 and the oil F. Therefore, when the vehicle 10 is running normally, the ECU 50 controls the pump P so that no oil F is present in the gap g. The position of the oil level SF when the vehicle 10 is running normally is indicated by height H2.

[0029] Fig. 4 is a schematic cross-sectional view showing the motor generator MG1 when the vehicle 10 is started in a low-temperature environment. In Fig. 4, the heights H1 and H2 are indicated by dashed lines. When the vehicle 10 is started in a low-temperature environment, the temperature of battery B may be lower than the appropriate temperature. If the temperature of battery B is lower than the appropriate temperature, the performance of battery B will be reduced.

[0030] Therefore, in the vehicle 10 according to the present disclosure, when the vehicle 10 is started in a low-temperature environment, the ECU 50 controls the pump P so that the liquid level SF is positioned within the gap g and the oil F contacts both the rotor 3 and the stator 2, thereby adjusting the amount of oil F sent to the circulation flow path L, in other words, the amount of oil F remaining in the case 1.

[0031] Specifically, when the vehicle 10 starts, the ECU 50 determines whether the temperature of the battery B received from the first sensor Se1 is lower than a predetermined first threshold value. For example, the first threshold value may be the lowest temperature at which the battery B operates as intended. For example, the first threshold value may be determined according to the specifications of the battery B. For example, the ECU 50 may store the first threshold value in the memory 52 in advance.

[0032] When the temperature of battery B is lower than the first threshold value, ECU 50 controls pump P to adjust the amount of oil F in case 1 so that the liquid level SF is at height H3. Height H3 is lower than height H1 of liquid level SF when vehicle 10 is stopped. Height H3 is also higher than height H2 when vehicle 10 is running normally. More specifically, as described above, height H3 is a position where liquid level SF is located within gap g and oil F contacts both rotor 3 and stator 2.

[0033] With this configuration, when the vehicle 10 starts, a portion of the oil in the motor-generator MG1 is sent to the circulation flow path L, causing the oil level SF to drop from a height H1. As shown in FIG. 3 , when the vehicle 10 is running normally, the oil level SF drops to a height H2 where no oil F is present in the gap g. However, as shown in FIG. 4 , when the vehicle 10 starts in a low-temperature environment, the oil level SF is maintained at a height H3 where the oil level SF is located in the gap g and the oil F contacts both the rotor 3 and the stator 2. Therefore, when the vehicle 10 starts in a low-temperature environment and the rotor 3 rotates, the oil F is heated due to friction between the rotor 3 and the oil F. Furthermore, because the oil F contacts the rotor 3, the oil F can recover heat generated by the rotor 3. Furthermore, because the oil F provides resistance to the rotation of the rotor 3, the heat generated by the rotor 3 increases. Referring to FIG. 1 , the heated oil F is supplied from the motor-generator MG1 to the battery B. Therefore, the battery B is quickly warmed up by the heated oil F.

[0034] Referring to FIG. 4 , for example, the adjustment of the oil level SF when the vehicle 10 is started in a low-temperature environment may be controlled by closed-loop control. Specifically, the ECU 50 may control the pump P so that the second sensor Se2 detects that the oil level SF of the oil F is higher than a predetermined level. Alternatively, the adjustment of the oil level SF may be controlled by open-loop control. Specifically, the ECU 50 may store in advance in the memory 52 an output of the pump P such that the oil level SF is located within the gap g and the oil F contacts both the rotor 3 and the stator 2. The ECU 50 may operate the pump P at this output when the vehicle 10 is started in a low-temperature environment. Furthermore, the ECU 50 may control at least one of the first valve V1 and the second valve V2 in addition to the pump P to adjust the oil level SF.

[0035] Furthermore, when the vehicle 10 starts in a low temperature environment, the ECU 50 operates the motor generator MG1 at a current phase angle that generates large copper loss, i.e., at a current phase angle that generates high heat in the rotor 3.

[0036] FIG. 5 is a graph showing the relationship between current phase angle and copper loss. In FIG. 5, the horizontal axis represents the current phase angle (°) of the motor-generator MG1, and the vertical axis represents the copper loss generated in the rotor 3. During normal driving, the motor-generator MG1 is operated at a current phase angle within range R, which generates small copper loss. In contrast, when the vehicle 10 starts in a low-temperature environment, generating large copper loss in the rotor 3 allows the oil F to be further heated by the rotor 3, which means that the battery B can be warmed up more quickly. Therefore, by operating the motor-generator MG1 at a current phase angle outside range R, the battery B can be warmed up more quickly.

[0037] Specifically, for example, the ECU 50 may operate the motor-generator MG1 at a current phase angle that generates copper loss greater than a predetermined second threshold. For example, the second threshold may be the maximum copper loss that occurs at a current phase angle used during normal driving. For example, the ECU 50 may store in advance in the memory 52 the current phase angle that generates copper loss greater than the second threshold.

[0038] Next, the operation of the vehicle 10 will be described.

[0039] FIG. 6 is a flowchart showing the operation of the vehicle 10 according to the embodiment.

[0040] For example, the operation shown in FIG. 6 may be initiated when the start / stop button of the vehicle 10 is pressed.

[0041] The processor 51 of the ECU 50 determines whether the temperature of the battery B measured by the first sensor Se1 is lower than a first threshold value (step S10).

[0042] If the temperature of battery B is lower than the first threshold value in step S10 (YES), processor 51 adjusts the height of the oil level SF in motor generator MG1 (step S12). Specifically, processor 51 controls pump P so that the oil level SF is located within gap g and the oil F contacts both rotor 3 and stator 2.

[0043] If the temperature of battery B is not lower than the first threshold value (NO) in step S10, the operation shown in Fig. 6 ends. In this case, processor 51 controls pump P at the output during normal driving. In this case, oil F is not present in gap g within motor generator MG1.

[0044] The processor 51 calculates the maximum torque (which may also be referred to as the "first torque") that can be output by the motor generator MG1 using the power that can be supplied from the battery B at the temperature measured by the first sensor Se1 (step S14). For example, the ECU 50 may store in the memory 52 a table that indicates the relationship between the temperature of the battery B and the maximum torque that can be output by the motor generator MG1. The ECU 50 may calculate the first torque by referring to this table.

[0045] The processor 51 calculates the maximum torque (which may also be referred to as the "second torque") required to travel to the destination (step S16). For example, the processor 51 may calculate the second torque based on information such as an image of the environment around the vehicle 10 captured by the camera 60, the planned route acquired from the navigation system 70, road surface conditions along the planned route, and data measured by other sensors (not shown). For example, the second torque may be the maximum torque among torques expected to be generated along the route to the destination.

[0046] The processor 51 determines whether the first torque calculated in step S14 is greater than the second torque calculated in step S16 (step S18). Note that in step S18, it may also be determined whether the difference between the first torque and the second torque is greater than a predetermined threshold. In this case, it can be determined whether the first torque has a sufficient margin of force.

[0047] If the first torque is greater than the second torque in step S18 (YES), the processor 51 operates the motor generator MG1 at a current phase angle that generates a large copper loss (step S20), and the operation shown in Fig. 6 ends. For example, the processor 51 may operate the motor generator MG1 at a current phase angle that generates a copper loss greater than a second threshold value that is pre-stored in the memory 52. ​​Thereafter, for example, if the temperature of the battery B increases to or exceeds the first threshold value, the processor 51 operates the pump P at the output for normal driving and operates the motor generator MG1 at the current phase angle for normal driving.

[0048] If the first torque is not greater than the second torque (NO) in step S18, the operation shown in Fig. 6 ends. In this case, the processor 51 operates the motor generator MG1 at the current phase angle during normal running.

[0049] As described above, the vehicle 10 according to this embodiment includes a battery B, a motor / generator MG1 driven by electric power from the battery B, a pump P that circulates oil through the motor / generator MG1, and an ECU 50. The ECU 50 includes a processor 51 and a memory 52 that stores instructions executed by the processor 51. In accordance with the instructions, the processor 51 is configured to control the pump P so that, when the temperature of the battery B is below a predetermined first threshold value at the start of the vehicle 10, the oil level SF of the oil F in the motor / generator MG1 is positioned within the gap g between the rotor 3 and the stator 2, and the oil F contacts both the rotor 3 and the stator 2. With this configuration, when the vehicle 10 starts and the rotor 3 rotates in a low-temperature environment, the oil F is heated due to friction between the rotor 3 and the oil F. Furthermore, because the oil F contacts the rotor 3, the oil F can recover heat generated by the rotor 3. Furthermore, the oil F provides resistance to the rotation of the rotor 3, increasing the heat generated by the rotor 3. The heated oil F is supplied from the motor generator MG1 to the battery B. Therefore, the heated oil F allows the battery B to be warmed up quickly.

[0050] Furthermore, in the vehicle 10, the processor 51 is configured to execute the following operations in accordance with the instructions: when the temperature of battery B is below a first threshold value at the start of the vehicle 10, calculate a first torque that can be output by the motor generator MG1 using the power that can be supplied from battery B at that temperature below the first threshold value, and a second torque that is necessary to travel to the destination; and when the first torque is greater than the second torque, operate the motor generator MG1 at a current phase angle that generates copper loss greater than the predetermined second threshold value. With this configuration, the oil F can be further heated by the copper loss generated in the rotor 3. Therefore, the battery B can be warmed up more quickly.

[0051] Although the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear to those skilled in the art that various modifications and alterations can be made within the scope of the claims, and it is understood that such modifications and alterations naturally fall within the technical scope of the present invention. Furthermore, the steps of the above-described embodiments do not have to be performed in the order described above, and may be performed in a different order as long as no technical contradiction occurs.

[0052] 2 Stator 3 Rotor 10 Vehicle 51 Processor 52 Memory B Battery F Oil g Gap MG1 Motor generator (oil-cooled motor generator) MG2 Motor generator (oil-cooled motor generator) P Pump SF Oil level

Claims

1. A vehicle comprising: a battery; an oil-cooled motor-generator driven by electric power from the battery; a pump that circulates oil through the oil-cooled motor-generator; and a controller, wherein the controller includes a processor and a memory that stores instructions to be executed by the processor, and the processor is configured to execute the instructions to control the pump so that, when the temperature of the battery is below a predetermined first threshold at the time of starting the vehicle, the oil level in the oil-cooled motor-generator is located in a gap between a rotor and a stator, and the oil contacts both the rotor and the stator.

2. The vehicle according to claim 1, wherein the processor is configured to execute the following operations according to the instructions: when the temperature of the battery is below the first threshold when the vehicle is started, calculate a first torque that can be output by the oil-cooled motor-generator using the power that can be supplied from the battery at a temperature below the first threshold, and a second torque that is necessary to travel to the destination; and when the first torque is greater than the second torque, operate the oil-cooled motor-generator at a current phase angle that generates copper loss greater than a predetermined second threshold.

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