vehicle

Abstract

To provide a vehicle with at least an electric motor as power source which can notify an operator of using oil having low electric insulation performance.SOLUTION: An electric insulation performance determination part 84 determines whether electric insulation performance of used oil is appropriate or not and a notification part 86 notifies an operator of the determination result of the electric insulation performance of the used oil. As a result, the operator can grasp whether the electric insulation performance of the used oil is appropriate or not to be capable of taking actions according to the electric insulation performance of the used oil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle having at least an electric motor as a power source for running. [Background technology]

[0002] In vehicles that have at least an electric motor as a power source for running, such as electric vehicles and hybrid vehicles, the oil used to cool the electric motor and lubricate the power transmission device that transmits the power of the electric motor to the drive wheels is required to have appropriate electrical insulation performance. For example, oil with excellent electrical insulation performance as described in Patent Document 1 is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-194002 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when oil with poor electrical insulation performance is used in a vehicle, a part of the current used to drive the vehicle may leak into the oil, which may cause a decrease in the running performance of the vehicle. In such a case, it is preferable to inform the driver that oil with poor electrical insulation performance is being used.

[0005] The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle that has at least an electric motor as a power source and is capable of notifying the driver that oil with low electrical insulation performance is being used. [Means for solving the problem]

[0006] The gist of the first invention is that a vehicle includes: (a) an electric motor that functions as a power source for traveling; and a power transmission device that transmits the power of the electric motor to drive wheels; an engine that functions as a power source separate from the electric motor;(b) an electrical insulation performance determination unit that determines the electrical insulation performance of the oil supplied to the electric motor and the parts of the power transmission device that require lubrication; and (c) a notification unit that notifies a driver of the result of the determination of the electrical insulation performance of the oil determined by the electrical insulation performance determination unit. of Preparation (d) the electrical insulation performance assessment unit determines that the electrical insulation performance of the oil is low when a torque ratio calculated by dividing the sum of an estimated torque of the electric motor and an estimated torque of the predetermined rotating member by an estimated torque of the engine during a running state in which the power of the engine is distributed to the electric motor and a predetermined rotating member mechanically connected to the drive wheels becomes equal to or greater than a first threshold value greater than 1.0. It is characterized by:

[0007] The gist of the second invention is that in the first invention, The notification unit is characterized in that, when the torque ratio is equal to or greater than the first threshold value, it notifies a driver that oil with low electrical insulation performance is being used.

[0008] The gist of the third invention is as follows: (a) a vehicle including an electric motor that functions as a power source for traveling and a power transmission device that transmits the power of the electric motor to drive wheels, (b) an electrical insulation performance determination unit that determines the electrical insulation performance of oil supplied to the electric motor and parts of the power transmission device that require lubrication, and (c) a notification unit that notifies a driver of the result of the determination of the electrical insulation performance of the oil by the electrical insulation performance determination unit; and (d) The electrical insulation performance determination unit is characterized in that it determines the electrical insulation performance of the oil from the relationship between an estimated torque of the electric motor, which is calculated based on a current applied to the electric motor, and an output torque of the electric motor.

[0009] The gist of the fourth invention is that in the third invention, the electrical insulation performance assessment unit determines that the electrical insulation performance of the oil is low when a torque ratio calculated by dividing an estimated torque of the motor, calculated based on a current applied to the motor, by an output torque of the motor becomes equal to or greater than a first threshold value greater than 1.0.

[0010] The gist of the fifth invention is as follows: , No. In the fourth aspect of the present invention, the notification unit is configured to notify a driver that oil with low electrical insulating performance is being used when the torque ratio is equal to or greater than the first threshold value.

[0011] The gist of the sixth invention is as follows: Second invention or A fifth aspect of the present invention is characterized in that, when the torque ratio is equal to or greater than a second threshold value that is greater than the first threshold value, the current applied to the electric motor is reduced. Effect of the Invention

[0012] According to the present invention, the electrical insulation performance of the oil being used is judged by the electrical insulation performance judgment unit, and the judgment result of the electrical insulation performance of the oil being used is reported by the notification unit, so that the driver can know whether the electrical insulation performance of the oil being used is appropriate. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram illustrating a schematic configuration of a hybrid vehicle to which the present invention is applied, and is also a functional block diagram illustrating a control system that controls the vehicle. [Diagram 2] 2 is a flowchart for explaining a main part of the control operation of the electronic control device of FIG. [Diagram 3] FIG. 13 is a diagram for explaining a schematic configuration of a vehicle corresponding to another embodiment of the present invention, and is also a diagram for explaining control functions and main parts of a control system for various controls in the vehicle. [Figure 4] FIG. 13 is a diagram illustrating a schematic configuration of a vehicle according to still another embodiment of the present invention, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0015] 1 is a schematic diagram illustrating a schematic configuration of a hybrid vehicle 8 (hereinafter, referred to as vehicle 8) to which the present invention is applied, and is also a functional block diagram illustrating a control system that controls the vehicle 8. The vehicle 8 is equipped with an engine 12 and a second electric motor MG2 as a power source for traveling, and a power transmission device 10 that transmits the power of the engine 12 and the second electric motor MG2 to drive wheels 36. The power transmission device 10 includes, in a case 40, a power distribution mechanism 16 for distributing the power output from the engine 12 to a first electric motor MG1 and a counter drive gear 14 (hereinafter referred to as the drive gear 14), a counter gear pair 20 consisting of the drive gear 14 and a counter driven gear 18 (hereinafter referred to as the driven gear 18) meshing with the drive gear 14, a second electric motor MG2 connected to the driven gear 18 via a reduction gear 22 so as to be capable of transmitting power, a final gear pair 28 consisting of a differential drive gear 24 and a differential driven gear 26, a differential device 30 (differential gear device), and a pair of left and right axles 32. The power transmission device 10 is preferably used in a FF (front engine, front drive) type vehicle that is horizontally mounted in the vehicle 8. The driven gear 18 and the differential drive gear 24 are each provided on a counter shaft 35 so as not to rotate relative to each other. The first electric motor MG1 and the second electric motor MG2 correspond to the electric motor of the present invention.

[0016] In the power transmission device 10, the power of the engine 12 is transmitted to the driven gear 18 via the power distribution mechanism 16 and the drive gear 14, and the power of the second electric motor MG2 is transmitted to the driven gear 18 via the reduction gear 22. The power transmitted to the driven gear 18 is transmitted to a pair of left and right drive wheels 36 sequentially via a final gear pair 28, a differential device 30, and a pair of left and right axles 32. In this way, the power transmission device 10 is configured to be able to transmit the power of the engine 12 and the second electric motor MG2 to the drive wheels 36.

[0017] A damper device 38 is provided between the engine 12 and the power distribution mechanism 16. The damper device 38 includes a damper spring 38s, and has a function of absorbing torque fluctuations by appropriately twisting the damper spring 38s in response to input torque.

[0018] The power distribution mechanism 16 is configured of a known single-pinion gear type planetary gear device having a sun gear S, a pinion gear P, a carrier CA that supports the pinion gear P so that it can rotate and revolve, and a ring gear R that meshes with the sun gear S via the pinion gear P as rotating elements. The sun gear S is connected to the first electric motor MG1 so as to be capable of transmitting power. The carrier CA is connected to the engine 12 so as to be capable of transmitting power. The ring gear R is connected to a pair of driving wheels 36 so as to be capable of transmitting power via a drive gear 14, a driven gear 18, a final gear pair 28, a differential device 30, a pair of axles 32, etc. in this order. In addition, the drive gear 14 is connected to the second electric motor MG2 so as to be capable of transmitting power via a counter gear pair 20 and a reduction gear 22. The ring gear R and the drive gear 14 are configured as an integrally molded compound gear. The compound gear on which the drive gear 14 is formed corresponds to a predetermined rotating member mechanically connected to the drive wheel of the present invention.

[0019] Since the sun gear S, the carrier CA, and the ring gear R are capable of rotating relative to each other, the power of the engine 12 is distributed to the first electric motor MG1 and the drive gear 14, and the first electric motor MG1 generates electricity using the power of the engine 12 distributed to the first electric motor MG1. The generated electrical energy is stored in the battery 74 via the inverter 76, and the generated electrical energy is used to drive the second electric motor MG2.

[0020] Thereby, the power distribution mechanism 16 is set, for example, in a continuously variable speed state (electrical CVT state) and functions as an electric continuously variable transmission in which the rotation of the ring gear R connected to the drive gear 14 is continuously changed regardless of the predetermined rotation of the engine 12. In other words, the power distribution mechanism 16 functions as an electric differential section (electric continuously variable transmission section) in which the differential state of the power distribution mechanism 16 is controlled by controlling the operating state of the first electric motor MG1 that functions as a differential motor.

[0021] In addition, oil is stored in the lower part of the case 40 of the power transmission device 10 to lubricate parts 34 requiring lubrication, such as various gears and various bearings, housed in the case 40. The oil stored in the lower part of the case 40 is also used to cool the first electric motor MG1 and the second electric motor MG2. For example, a part of the differential driven gear 26 is immersed in oil, and the differential driven gear 26 scoops up the immersed oil during driving, thereby supplying oil to parts requiring lubrication 34, such as various gears and various bearings, the first electric motor MG1, and the second electric motor MG2.

[0022] In addition, in addition to the supply path provided by the scraping up of the differential driven gear 26, for example, a cooling circuit (not shown) for cooling the first electric motor MG1 and the second electric motor MG2 may be provided, and oil pumped up by an oil pump (not shown) may be configured to be supplied to the first electric motor MG1 and the second electric motor MG2 via the cooling circuit.

[0023] The vehicle 8 is equipped with an electronic control device 80 for executing various controls including travel control of the vehicle 8. The electronic control device 80 receives, for example, a signal indicative of a shift operation position Psh of a shift lever 43 detected by a shift position sensor 42, a signal indicative of an accelerator opening θacc which is an operation amount of an accelerator pedal 45 as an acceleration request amount by the driver for the vehicle 8 detected by an accelerator opening sensor 44, a signal indicative of an operation (brake on) Bon of a foot brake pedal 47 which is a service brake and indicates an operation (depression operation) of a foot brake which is a service brake detected by a brake switch 46, a signal indicative of a throttle valve opening θth which is an opening amount of an electronic throttle valve detected by a throttle valve opening sensor 48, a signal indicative of a rotation angle Acr of a crankshaft and an engine rotation speed Ne which is a rotation speed of the engine 12 detected by a crank position sensor 50, a signal indicative of an output rotation speed Nout which is a rotation speed of the drive gear 14 corresponding to a vehicle speed V detected by an output rotation speed sensor 52, a rotation angle θmg1( the rotation angle θmg2 (electrical angle) and the MG2 rotation speed Nmg2 (rotational speed) of the second electric motor MG2 detected by the second resolver 56; a signal representing the battery temperature THbat, the battery charge / discharge current Ibat, and the battery voltage Vbat of the battery 74 detected by the battery sensor 58; a signal representing the applied current Img1 to the first electric motor MG1 detected by the first current sensor 60; a signal representing the applied current Img2 to the second electric motor MG2 detected by the second current sensor 62; the rotation speed Nr of each wheel detected by the wheel speed sensor 64; a signal representing the oil temperature Toil of the oil sealed in the case 40 detected by the oil temperature sensor 66; a signal representing the operating state of the engine 12 detected by the engine state detection sensor 68 (intake air amount Qair, intake air temperature Tair, fuel injection amount M, ignition timing Tig, etc.);

[0024] Further, the electronic control device 80 outputs, for example, an engine control command signal Se for controlling the output of the engine 12, a motor control command signal Smg to the inverter 76 for controlling the drive of the first electric motor MG1 and the second electric motor MG2, and the like.

[0025] The electronic control device 80 functionally includes a hybrid control unit 82 as a hybrid control means for executing hybrid control of the vehicle 8. The hybrid control unit 82 selectively establishes, depending on the vehicle running state, a motor running mode in which the engine 12 is stopped and the vehicle 8 is run solely using the second electric motor MG2 as a power source, an engine running mode (normal running mode) in which the reaction force against the power of the engine 12 is borne by the power generation of the first electric motor MG1, and the engine direct torque is transmitted to the drive gear 14 and the second electric motor MG2 is driven by the power generated by the first electric motor MG1 to transmit the torque to the driven gear 18, and an assist running mode in which the driving force of the second electric motor MG2 using the power from the battery 74 is further added in the engine running mode to run the vehicle, depending on the vehicle running state. In addition, the hybrid control unit 82 can control the gear ratio γ0 (engine rotation speed Ne / output rotation speed Nout) in the power transmission device 10, for example, by operating the engine 12 in an efficient operating range while optimizing the distribution of driving force between the engine 12 and the second electric motor MG2 and the reaction force due to the power generation of the first electric motor MG1.

[0026] In the power transmission device 10, a part of the stator coil constituting the first electric motor MG1 and the second electric motor MG2 (hereinafter, each electric motor MG) is immersed in the oil stored in the case 40. Therefore, if the electrical insulation performance of the stored oil is low, there is a possibility that the current leaking from the stator coil increases. At this time, an electrical short circuit or spark may occur, causing the oil to heat up abnormally, which may lead to a breakdown of the device. In addition, there is a possibility that the output of the electric motor MG may decrease, leading to a decrease in the vehicle driving performance and a decrease in the cruising distance. In response to this, the electronic control device 80 is functionally provided with an electrical insulation performance determination unit 84 that determines the electrical insulation performance of the oil supplied to the electric motor MG and the lubrication-requiring unit 34 while the vehicle is running. Furthermore, the electronic control device 80 is functionally provided with an informing unit 86 that informs the driver of the result of the electrical insulation performance determined by the electrical insulation performance determination unit 84.

[0027] The electrical insulation performance of the oil can be determined from the relationship between the estimated MG torque Tmgest (Tmg1est, Tmg2est), which is the estimated torque of each electric motor MG calculated based on each applied current Img (Img1, Img2) to each electric motor MG, and each MG torque Tmg (Tmg1, Tmg2), which is the output torque of each electric motor MG. When the electrical insulation performance of the oil is good, each estimated MG torque Tmgest (Tmg1est, Tmg2est) of each electric motor MG estimated from each applied current Img1 and each MG rotation speed Nmg (Nmg1, Nmg2) is equal or approximately equal to each MG torque Tmg, which is the actual output torque of the electric motor MG. Therefore, when the value calculated by dividing each estimated MG torque Tmgest by each MG torque Tmg is defined as each torque ratio RT (=Tmgest / Tmg), when the electrical insulation performance of the oil is good, each torque ratio RT is 1.0 or approximately 1.0. On the other hand, when the electrical insulation of the oil is low, the amount of leakage current increases, and the MG torque Tmg, which is the actual output torque of the motor MG, becomes smaller than the estimated MG torque Tmgest estimated based on the applied current Img. As a result, the torque ratios RT (=Tmgest / Tmg) become larger than 1.0. The lower the electrical insulation of the oil, the larger the torque ratio RT becomes. From this, it is possible to calculate the torque ratios RT and determine whether or not oil with low electrical insulation is used based on whether or not the torque ratios RT are equal to or greater than a first threshold value K1 that is predefined and is greater than 1.0. Specifically, if the torque ratios RT are less than the first threshold value K1, it is determined that the oil has appropriate electrical insulation, and if the torque ratios RT are equal to or greater than the first threshold value K1, it is determined that oil with low electrical insulation is used. The first threshold value K1 is determined in advance experimentally or by design, and is set to a threshold value at which the electrical insulation of the oil is within an allowable range.

[0028] Each estimated MG torque Tmgest of each electric motor MG can be calculated from each applied current Img to each electric motor MG and each MG rotation speed Nmg of each electric motor MG. Each applied current Img to each electric motor MG can be detected by the first current sensor 60 and the second current sensor 62. Each MG rotation speed Nmg of each electric motor MG can be detected by the first resolver 54 and the second resolver 56. In addition, each MG torque Tmg, which is the output torque of each electric motor MG, can be detected by providing a torque sensor that detects the MG torque Tmg of each electric motor MG. Therefore, each torque ratio RT can be calculated by providing a torque sensor that detects the MG torque Tmg of each electric motor MG for each electric motor MG, and the electrical insulation performance of the oil can be determined from each calculated torque ratio RT. However, if a torque sensor is provided for each electric motor MG, the number of parts increases. Below, a method of determining the electrical insulation performance of the oil without using a torque sensor will be described.

[0029] Since the vehicle 8 includes the power distribution mechanism 16 that distributes the power of the engine 12 to the first electric motor MG1 and the drive wheels 36, the vehicle may enter a running state in which the following formula (1) holds. In formula (1), Te represents engine torque, Tmg1 represents the output torque of the first electric motor MG1 (i.e., MG1 torque Tmg1), and Td represents the drive torque (hereinafter, drive torque Td) output from the drive gear 14 integrally formed with the ring gear R that constitutes the power distribution mechanism 16. The drive torque Td of the drive gear 14 is equal to the torque output from the ring gear R. Te = Tmg1 + Td (1)

[0030] Here, formula (1) holds true during engine driving mode, in which the reaction force against the power of the engine 12 is borne by the power generation of the first electric motor MG1, and the direct torque of the engine 12 is transmitted to the drive gear 14, and the second electric motor MG2 is driven by the power generated by the first electric motor MG1 to transmit the torque to the driven gear 18. When determining the electrical insulation performance of the oil, the electrical insulation performance determination unit 84 first determines whether or not the driving condition under which formula (1) holds true is satisfied. For example, when all of the following are satisfied: the engine is in a driving state, the MG1 rotation speed Nmg1 of the first electric motor MG1 is in a forward rotation (i.e., in a regenerative state), and the vehicle is in a driving state in which no power is exchanged with the battery 74, the electrical insulation performance determination unit 84 determines that the driving condition under which formula (1) holds true is satisfied.

[0031] When the driving conditions satisfying the relationship of formula (1) are satisfied, the electrical insulation performance judgment unit 84 starts control for judging the electrical insulation performance of the oil, and first calculates the torque ratio RT based on the following formula (2). In formula (2), Teest indicates an estimated value of the engine torque Te (hereinafter, estimated engine torque Teest), Tmg1est indicates an estimated value of the MG1 torque Tmg1 of the first electric motor MG1 (hereinafter, estimated MG1 torque Tmg1est), and Tdest indicates an estimated value of the driving torque Td output from the drive gear 14 (hereinafter, estimated driving torque Tdest). From formula (2), the torque ratio RT indicates a value obtained by dividing the sum of the estimated values ​​of the MG1 torque Tmg1 and the driving torque Td distributed by the power distribution mechanism 16 by the estimated value of the engine torque Te. The estimated driving torque Tdest corresponds to the estimated torque of a predetermined rotating member of the present invention. RT=(Tmg1est+Tdest) / Teest...(2)

[0032] In a state where there is no current leakage from each electric motor MG to the oil, the MG torque Tmg of each electric motor MG does not decrease with respect to each applied current Img, so the torque ratio RT is 1.0. On the other hand, when oil with low electrical insulation performance is used, the amount of current leakage from the electric motor MG increases. In this case, when the applied current Img of each electric motor MG increases, the estimated MG torque Tmgest calculated based on each applied current Img increases, but the actual MG torque Tmg of each electric motor MG does not increase with the current leakage. In addition, in a driving state where formula (1) is established, the estimated engine torque Teest does not increase either. As a result, when oil with low electrical insulation performance is used, the sum of the estimated MG1 torque Tmg1est and the estimated driving torque Tdest becomes larger than the estimated engine torque Teest, and the torque ratio RT calculated based on formula (2) becomes larger than 1.0.

[0033] The estimated MG1 torque Tmg1est in equation (2) is calculated by applying the applied current Img1 detected by the first current sensor 60 and the MG1 rotation speed Nmg1 detected by the first resolver 54 to a predetermined relationship map or relational expression. The estimated engine torque Teest is calculated by applying the engine rotation speed Ne and each state (intake air amount Qair, intake air temperature Tair, fuel injection amount M, ignition timing Tig, etc.) detected by the engine state detection sensor 68 to the predetermined relationship map or relational expression.

[0034] The estimated drive torque Tdest of the drive gear 14 in the formula (2) is calculated based on the following formula (3). Here, Tconest corresponds to the estimated torque of the differential driven gear 26 constituting the final gear pair 28 (hereinafter, estimated differential shaft torque Tdiffest), γ1 corresponds to the gear ratio mechanically defined between the drive gear 14 and the differential driven gear 26 (hereinafter, first gear ratio γ1), Tmg2est corresponds to the estimated value of the MG2 torque of the second electric motor MG2 (hereinafter, estimated MG2 torque Tmg2est), and γ2 corresponds to the gear ratio mechanically defined between the second electric motor MG2 and the drive gear 14 (hereinafter, second gear ratio γ2). The first gear ratio γ1 is equal to the ratio (=Nd / Ndiff) between the rotation speed Nd of the drive gear 14 and the rotation speed Ndiff of the differential driven gear 26. The second gear ratio γ2 is equal to the ratio (=Nd / Nmg2) between the rotation speed Nd of the drive gear 14 and the MG2 rotation speed Nmg2 of the second electric motor MG2. The estimated drive torque Tdest can be calculated more accurately by taking into account other factors such as the oil temperature Toil. Tdest=Tdiffest / γ1-Tmg2est / γ2···(3)

[0035] The estimated differential shaft torque Tdiffest is calculated, for example, by applying the longitudinal acceleration G detected by the acceleration sensor 70 to a predefined relationship map or relational expression. The estimated MG2 torque Tmg2est is calculated by applying the applied current Img2 detected by the second current sensor 62 and the MG2 rotation speed Nmg2 detected by the second resolver 56 to the predefined relationship map or relational expression.

[0036] The electrical insulation performance judgment unit 84 calculates the torque ratio RT from the formula (2) and the formula (3), and judges the electrical insulation performance of the oil based on the calculated torque ratio RT. When the electrical insulation performance of the oil is low, the sum of the estimated MG1 torque Tmg1est and the estimated driving torque Tdest becomes larger with respect to the estimated engine torque Teest. Therefore, when the electrical insulation performance of the oil is low, the torque ratio RT becomes larger than 1.0, and further, the lower the electrical insulation performance of the oil becomes, the larger the torque ratio RT becomes. Thus, when the electrical insulation performance judgment unit 84 calculates the torque ratio RT, it judges whether the torque ratio RT is equal to or larger than the first threshold value K1, and judges that oil with low electrical insulation performance is used if the torque ratio RT is equal to or larger than the first threshold value K1. In this way, in a driving state in which the relationship of formula (1) is established, the electrical insulation performance of the oil can be judged based on the torque ratio RT calculated from formula (2) without providing a torque sensor. The first threshold value K1 is obtained in advance experimentally or by design, and is set to a threshold value at which the electrical insulation performance of the oil is within an allowable range.

[0037] When the torque ratio RT is equal to or greater than the first threshold value K1, the notification unit 86 notifies the driver that oil with low electrical insulation performance is being used. The notification unit 86 notifies the driver that oil with low electrical insulation performance is being used, for example, by turning on a warning light 88 provided at the driver's seat or by generating a warning sound from a sound generating device 90. This allows the driver to know that oil with low electrical insulation performance is being used, and the driver can take measures such as changing the oil.

[0038] Here, if the deterioration of the electrical insulation performance becomes significant, the amount of current leaking into the oil increases, and electrical shorts and sparks increase, which may lead to abnormal heat generation in the oil and failure of the device. Therefore, when the torque ratio RT is equal to or greater than the first threshold value K1, the electrical insulation performance determination unit 84 further determines whether the torque ratio RT is equal to or greater than a second threshold value K2 that is greater than the first threshold value K1. The second threshold value K2 is determined in advance experimentally or by design, and is set to a threshold value within a range in which normal driving is permitted despite low electrical insulation performance. In other words, if the torque ratio RT becomes equal to or greater than the second threshold value K2, there is a risk of abnormal heat generation in the oil.

[0039] When the torque ratio RT is equal to or greater than the second threshold value K2, the electrical insulation performance determining unit 84 outputs a command to the hybrid control unit 82 to reduce the applied currents Img1, Img2 to the first electric motor MG1 and the second electric motor MG2. In response to this, the hybrid control unit 82 outputs a motor control command signal Smg to the inverter 76 to reduce the applied currents Img1, Img2 to the first electric motor MG1 and the second electric motor MG2. As a result, the amount of current leakage from each electric motor MG to the oil is reduced, and electrical short circuits and sparks are reduced, preventing abnormal heat generation in the oil.

[0040] Furthermore, even when the torque ratio RT becomes equal to or higher than the second threshold value K2, the notification unit 86 notifies the driver that oil with low electrical insulation performance is being used by using the warning light 88, the sounding device 90, etc. Furthermore, when the torque ratio RT becomes equal to or higher than the second threshold value K2, the notification unit 86 can also notify the driver that the driving performance will deteriorate as a result of the currents Img1, Img2 applied to the first electric motor MG1 and the second electric motor MG2 being reduced.

[0041] 2 is a flowchart for explaining the main control operations of the electronic control device 80, and is a flowchart for explaining the control operations for determining whether the oil used in the power transmission device 10 while the vehicle is running has low electrical insulation performance. This flowchart is executed, for example, every time the oil filled in the case 40 is changed.

[0042] In FIG. 2, first, in step S10 (hereinafter, step is omitted) corresponding to the control function of the electrical insulation performance judgment unit 84, it is judged whether or not the running condition for judging the electrical insulation performance of the oil is established. If the judgment in S10 is negative, this routine is terminated. If the judgment in S10 is positive, in S20 corresponding to the control function of the electrical insulation performance judgment unit 84, control for judging the electrical insulation performance of the oil is started, and various specifications including each applied current Img and MG rotation speed Nmg of each electric motor MG and engine rotation speed Ne of the engine 12 are detected. Next, in S30 corresponding to the control function of the electrical insulation performance judgment unit 84, an estimated engine torque Teest of the engine 12 is calculated based on the engine rotation speed Ne and the operating state of the engine 12 detected by the engine state detection sensor 68 (intake air amount Qair, intake air temperature Tair, fuel injection amount M, ignition timing Tig, etc.). In S40, which corresponds to the control function of the electrical insulation performance determining unit 84, the estimated MG1 torque Tmg1est and the estimated drive torque Tdest of the first electric motor MG1 are calculated. In S50, which corresponds to the control function of the electrical insulation performance determining unit 84, the torque ratio RT is calculated by applying the estimated engine torque Teest calculated in S30, and the estimated MG1 torque Tmg1est and the estimated drive torque Tdest calculated in S40 to the formula (2), and it is determined whether the torque ratio RT is equal to or greater than the first threshold value K1. If the determination in S50 is negative, it is determined that the electrical insulation performance of the oil is appropriate, and in S80, which corresponds to the control function of the electrical insulation performance determining unit 84, the control for determining the electrical insulation performance of the oil is terminated and normal control is resumed. If the determination in S50 is positive, it is determined in S60, which corresponds to the control function of the electrical insulation performance determining unit 84, whether the torque ratio RT is equal to or greater than the second threshold value K2. If the judgment in S60 is negative, the torque ratio RT is equal to or greater than the first threshold value K1 and is less than the second threshold value K2, so that in S90, which corresponds to the control function of the notification unit 86, a warning light 88 is turned on to notify the driver that oil with low electrical insulation performance is being used.If the determination in S90 is positive, the torque ratio RT is equal to or greater than the second threshold value K2, so that in S70, which corresponds to the control function of the notification unit 86, the warning light 88 is turned on to notify that oil with low electrical insulation performance is being used, and the applied current Img of each electric motor MG is reduced to prevent abnormal heat generation of the oil.

[0043] As described above, according to this embodiment, the electrical insulation performance of the oil being used is judged by the electrical insulation performance judgment unit 84 and the judgment result of the electrical insulation performance of the oil being used is reported by the notification unit 86, so that the driver can know whether the electrical insulation performance of the oil being used is appropriate.

[0044] Next, another embodiment of the present invention will be described. In the following description, the same reference numerals are used to designate parts common to the above embodiment, and the description thereof will be omitted. EXAMPLES

[0045] Fig. 3 is a diagram for explaining a schematic configuration of a vehicle 100 corresponding to another embodiment of the present invention, and also a diagram for explaining main parts of a control function and a control system for various controls in the vehicle 100. In Fig. 1, the vehicle 100 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are power sources for traveling. The vehicle 100 is equipped with a power transmission device 104 that transmits the power of the engine 12 and the electric motor MG to driving wheels 102. The engine 12 is basically the same as in the above-mentioned embodiment, so it is given the same reference numeral and its description is omitted.

[0046] The electric motor MG is connected to a battery 108 provided in the vehicle 100 via an inverter 106 provided in the vehicle 100. The inverter 106 is controlled by an electronic control device 150, whereby the MG torque Tmg, which is the output torque of the electric motor MG, is controlled.

[0047] The power transmission device 104 includes a first clutch 112, a second clutch 114, an automatic transmission 116, and the like, in a case 110 which is a non-rotating member attached to the vehicle body. The first clutch 112 is a clutch provided between the engine 12 and the electric motor MG in the power transmission path between the engine 12 and the drive wheels 102. The second clutch 114 is a clutch provided between the first clutch 112 and the automatic transmission 116 in the power transmission path between the engine 12 and the drive wheels 102.

[0048] The automatic transmission 116 is interposed in a power transmission path between the second clutch 114 and the drive wheels 102. The power transmission device 104 includes a propeller shaft 120 connected to a transmission output shaft 118 which is an output rotating member of the automatic transmission 116, a differential device 122 connected to the propeller shaft 120, a pair of drive shafts 124 connected to the differential device 122, and the like. The power transmission device 104 also includes an engine connecting shaft 126 which connects the engine 12 and the first clutch 112, an electric motor connecting shaft 128 which connects the first clutch 112 and the second clutch 114, a transmission input shaft 130 which connects the second clutch 114 and the automatic transmission 116, and the like.

[0049] The automatic transmission 116 is a known planetary gear type automatic transmission that includes, for example, one or more planetary gear sets (not shown) and a plurality of engagement devices CB. The engagement devices CB are hydraulic friction engagement devices that are configured, for example, by a multi-plate or single-plate clutch or brake pressed by a hydraulic actuator, or a band brake tightened by a hydraulic actuator. The engagement devices CB are switched between control states such as an engaged state and a released state by changing the CB torque Tcb, which is the torque capacity of each of the engagement devices CB, by the regulated engagement pressure PRcb supplied from the hydraulic control circuit 132. The engagement devices CB are configured, for example, by four clutches C1 to C4 and two brakes B1 and B2. The automatic transmission 116 is configured to be able to shift to a plurality of gear stages by changing the combination of the engagement devices CB that are engaged.

[0050] The first clutch 112 and the second clutch 114 are wet or dry friction engagement devices constituted by a multi-plate or single-plate clutch pressed by a hydraulic actuator (not shown). The first clutch 112 and the second clutch 114 have their control states, such as an engaged state and a released state, switched by the electronic control device 150 controlling the operating state of the hydraulic actuator.

[0051] When the first clutch 112 is engaged, the engine 12 and the electric motor MG are connected to the power transmission path via the first clutch 112. When the second clutch 114 is engaged, the electric motor MG and the automatic transmission 116 are connected to the power transmission path via the second clutch 114. For example, when the first clutch 112 and the second clutch 114 are engaged, the engine 12, the electric motor MG, and the driving wheels 102 are connected to be able to transmit power via the automatic transmission 116 or the like. At this time, hybrid running by the power of the engine 12 and the electric motor MG is possible. When the first clutch 112 is released and the second clutch 114 is engaged, the power transmission of the engine 12 is interrupted, while the electric motor MG and the driving wheels 102 are connected to be able to transmit power. At this time, motor running by the power of the electric motor MG is possible.

[0052] The vehicle 100 includes an electric oil pump 136 driven by a pump motor 134. The vehicle 100 also includes a mechanical oil pump (not shown) driven by at least one of the engine 12 and the electric motor MG. The hydraulic oil discharged by the electric oil pump 136 and the mechanical oil pump is supplied to a hydraulic control circuit 132. The hydraulic control circuit 132 supplies an engagement pressure PRcb supplied to each engagement device CB, a first hydraulic pressure PRk1 supplied to the first clutch 112, a second hydraulic pressure PRk2 supplied to the second clutch 114, and the like, which are each adjusted based on the hydraulic oil discharged by at least one of the electric oil pump 136 and the mechanical oil pump.

[0053] Moreover, various signals based on detection values ​​by various sensors provided in the vehicle 100 are respectively supplied to an electronic control device 150 that executes various controls of the vehicle 100. Among the various detection values ​​detected by the various sensors, those that are the same as those in the above-described first embodiment are given the same reference numerals as in the above-described first embodiment and their description is omitted. In this embodiment, a resolver 140 that detects the rotation angle θmg and the MG rotation speed Nmg of the electric motor MG, and a current sensor 142 that detects the applied current Img of the electric motor MG are provided.

[0054] The electronic control device 150 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Sbc for controlling the engagement device CB, a hydraulic control command signal Sk for controlling the first clutch 112 and the second clutch 114, a pump control command signal Seop for controlling the electric oil pump 136, etc.) to each device (e.g., an engine control device 144, an inverter 106, a hydraulic control circuit 132, a pump motor 134, etc.) provided in the vehicle 100.

[0055] In order to realize various controls in the vehicle 100, the electronic control device 150 includes a hybrid control unit 152 as a hybrid control means, a gear shift control unit 154 as a gear shift control means, an electrical insulation performance determination unit 156 as an electrical insulation performance detection means, and a notification unit 158 ​​as a notification means.

[0056] The hybrid control unit 152 establishes, for example, a motor driving mode in which the engine 12 is stopped and the vehicle 100 is driven solely by the electric motor MG as a power source, and an engine driving mode in which the engine 12 is driven and the vehicle 100 is driven solely by the power of the engine 12, depending on the vehicle driving state.

[0057] The gear shift control unit 154 determines the gear position according to the driving conditions based on, for example, the accelerator opening θacc and the vehicle speed V, and outputs a CB hydraulic control command signal Sbc to the hydraulic control circuit 132 to shift to the determined gear position.

[0058] When a driving condition that allows the electric insulation performance of the oil to be determined is satisfied during vehicle driving, the electric insulation performance determination unit 156 starts control to determine the electric insulation performance of the oil. For example, when the vehicle is driving in an engine driving mode in which both the first clutch 112 and the second clutch 114 are engaged, and a part of the power of the engine 12 is transmitted to the electric motor MG to generate electricity, the electric insulation performance determination unit 156 determines that the driving condition that allows the electric insulation performance of the oil to be determined is satisfied. At this time, the vehicle is in a driving state in which the power of the engine 12 is distributed to the electric motor MG and the transmission input shaft 130, and the following formula (4) is satisfied. Here, Tmg corresponds to the MG torque of the electric motor MG (hereinafter, MG torque Tmg), and Tin corresponds to the input torque transmitted to the transmission input shaft 130 (hereinafter, input torque Tin). In other words, the electric insulation performance determination unit 156 determines whether the driving state is such that formula (4) is satisfied when starting control to determine the electric insulation performance of the oil. Te = Tmg + Tin (4)

[0059] Furthermore, when it is determined that the driving conditions that allow the electrical insulation performance of the oil to be determined are satisfied, the electrical insulation performance determination unit 156 calculates the torque ratio RT based on the following formula (5). In formula (5), Tmgest indicates an estimated value of the MG torque Tmg of the electric motor MG (hereinafter, estimated MG torque Tmgest), Tinest indicates an estimated value of the input torque Tin (hereinafter, estimated input torque Tinest), and Teest indicates an estimated value of the engine torque Te of the engine 12 (hereinafter, estimated engine torque Teest). Based on formula (5), the torque ratio RT is calculated by dividing the sum of the estimated MG torque Tmgest and the estimated input torque Tinest of the electric motor MG by the estimated engine torque Teest. RT=(Tmgest+Tinest) / Teest...(5)

[0060] The estimated MG torque Tmgest in equation (5) is calculated based on the MG rotation speed Nmg detected by the resolver 140 and the applied current Img detected by the current sensor 142. The estimated engine torque Teest in equation (5) is estimated from the intake air amount Qair, the intake air temperature Tair, the fuel injection amount M, the ignition timing Tig, etc., as in the above-mentioned embodiment. The estimated input torque Tinest in equation (5) is calculated by applying the current longitudinal acceleration G and the gear ratio γat of the automatic transmission 116 to a relation map or relation equation for estimating the input torque Tin, which is configured from, for example, the longitudinal acceleration G, the gear ratio γat of the automatic transmission 116, etc.

[0061] The electrical insulation performance determination unit 156 calculates the torque ratio RT based on the formulas (4) and (5), and determines whether or not oil with low electrical insulation performance is used based on the torque ratio RT. When oil with high electrical insulation performance is used, the amount of current leakage is small, so the sum of the estimated MG torque Tmgest and the estimated input torque Tinest is equal to or approximately equal to the estimated engine torque Teest. That is, the torque ratio RT is 1.0 or a value close to 1.0. On the other hand, when oil with low electrical insulation performance is used, the amount of current leakage increases, so the actual MG torque Tmg decreases, while the estimated MG torque Tmgest does not change because it is estimated from the applied current Img. Therefore, the more the amount of current leakage increases, the larger the sum of the estimated MG torque Tmgest and the estimated input torque Tinest becomes. Also, since the estimated engine torque Teest does not change, when oil with low electrical insulation performance is used, the torque ratio RT becomes larger than 1.0, and the lower the electrical insulation performance, the larger the torque ratio RT becomes. Therefore, it is possible to determine whether oil with low electrical insulation performance is being used based on the torque ratio RT calculated by equation (5). Note that the control operation of the electrical insulation performance determination unit 156 after the torque ratio RT is calculated is basically the same as that of the electrical insulation performance determination unit 84 in the previously described embodiment, and therefore a description thereof will be omitted. Also, the control function of the notification unit 158 ​​is basically the same as that of the notification unit 86 in the previously described embodiment, and therefore a description thereof will be omitted.

[0062] As described above, even in a one-motor type hybrid vehicle having one electric motor MG, it is possible to determine whether or not oil with low electrical insulation performance is being used based on the control operation of the electrical insulation performance judgment unit 156 and the notification unit 158, and if oil with low electrical insulation performance is being used, the driver can be notified to that effect. EXAMPLES

[0063] 4 is a diagram illustrating a schematic configuration of a vehicle 200 according to still another embodiment of the present invention, and also illustrates main parts of a control function and a control system for various controls in the vehicle 200. The vehicle 200 is an electric vehicle powered only by an electric motor MG. The vehicle 200 includes a power transmission device 204 that transmits the power of the electric motor MG to driving wheels 202.

[0064] Power transmission device 204 includes a connecting / disconnecting clutch 208, an automatic transmission 210, and the like, in a case 206, which is a non-rotating member attached to the vehicle body. Connecting / disconnecting clutch 208 is provided between electric motor MG and automatic transmission 210, and is provided to selectively connect and disconnect the power transmission path between electric motor MG and automatic transmission 210.

[0065] The electric motor MG is connected to a battery 232 provided in the vehicle 200 via an inverter 230 provided in the vehicle 200. The inverter 230 is controlled by an electronic control device 250, whereby the MG torque Tmg, which is the output torque of the electric motor MG, is controlled.

[0066] The automatic transmission 210 is a known planetary gear type automatic transmission that includes, for example, one or more planetary gear devices (not shown) and a plurality of engagement devices CB, similar to the automatic transmission 116 of the above-described embodiment. A detailed description of the automatic transmission 210 will be omitted.

[0067] The power transmission device 204 includes a propeller shaft 214 connected to a transmission output shaft 212 of the automatic transmission 210, a differential device 216 connected to the propeller shaft 214, a pair of drive shafts 218 connected to the differential device 216, etc. The power transmission device 204 also includes an electric motor connecting shaft 220 connected to the electric motor MG, a transmission input shaft 222 of the automatic transmission 210, the transmission output shaft 212, etc.

[0068] The make-and-break clutch 208 is a wet or dry friction engagement device composed of a multiple-plate or single-plate clutch pressed by a hydraulic actuator (not shown). The electronic control device 250 controls the operating state of the hydraulic actuator, and thereby the make-and-break clutch 208 switches between an engaged state, a released state, and other control states.

[0069] For example, when the disconnecting clutch 208 is engaged, the power of the electric motor MG can be transmitted to the drive wheels 202 via the automatic transmission 210. At this time, motor driving by the power of the electric motor MG is possible. On the other hand, when the disconnecting clutch 208 is released, the power transmission between the engine 12 and the drive wheels 202 is interrupted.

[0070] The vehicle 200 is equipped with an electric oil pump 226 driven by a pump motor 224. Furthermore, the vehicle 200 is equipped with a mechanical oil pump (not shown) driven by an electric motor MG. The hydraulic oil discharged by the electric oil pump 226 and the mechanical oil pump is supplied to a hydraulic control circuit 228. The hydraulic control circuit 228 supplies an engagement pressure PRcb supplied to each engagement device CB, a disconnection hydraulic pressure PRk supplied to the disconnection clutch 208, and the like, which are each adjusted based on the hydraulic oil discharged by at least one of the electric oil pump 226 and the mechanical oil pump.

[0071] Moreover, various signals based on detection values ​​by various sensors provided in the vehicle 200 are respectively supplied to the electronic control device 250 which executes various controls of the vehicle 200. The explanation of the various sensors is basically the same as in the above-mentioned second embodiment, so the same reference numerals are used and the explanation is omitted. In addition, since the engine 12 is not provided in this embodiment, the crank position sensor 50 and the engine state detection sensor 68 are not provided.

[0072] The electronic control device 250 outputs various command signals (e.g., an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Sbc for controlling the engagement device CB, a hydraulic control command signal Sk for controlling the on-off clutch 208, a pump control command signal Seop for controlling the electric oil pump 226, etc.) to each device (e.g., the inverter 230, the hydraulic control circuit 228, the pump motor 224, etc.) provided in the vehicle 200.

[0073] In order to realize various controls in the vehicle 200, the electronic control device 250 includes an electric motor control unit 252 as an electric motor control means, a gear shift control unit 254 as a gear shift control means, an electric insulation performance determination unit 256 as an electric insulation performance detection means, and a notification unit 258 as a notification means.

[0074] The electric motor control unit 252 outputs an MG control command signal Sm to the inverter 230 for causing the vehicle 200 to run using the electric motor MG as a power source, for example, with the on-off clutch 208 engaged.

[0075] The electrical insulation performance determination unit 256 determines whether or not a driving condition exists under which the electrical insulation performance of the oil can be determined, based on whether the vehicle is in a driving state in which the power of the electric motor MG is transmitted to the driving wheels 202. The electrical insulation performance determination unit 256 determines whether or not a driving condition exists under which the electrical insulation performance of the oil can be determined, based on whether, for example, the disconnecting clutch 208 is in an engaged state and a predetermined gear shift stage is established in the automatic transmission 210.

[0076] When a driving condition that allows the electrical insulation performance of the oil to be determined is satisfied, the electrical insulation performance determination unit 256 calculates the torque ratio RT based on the following formula (6). In formula (6), Tmgest indicates an estimated value of the MG torque Tmg of the electric motor MG (hereinafter, the estimated MG torque Tmgest), and Tinest indicates an estimated value of the input torque Tin input to the transmission input shaft 222 (hereinafter, the estimated input torque Tinest). Here, in the engaged state of the disconnecting clutch 208, the electric motor connecting shaft 220 and the transmission input shaft 222 are connected via the disconnecting clutch 208, so that the input torque Tin has the same value as the MG torque Tmg, which is the output torque of the electric motor MG. Based on formula (6), the torque ratio RT is calculated by dividing the estimated MG torque Tmgest of the electric motor MG by the estimated input torque Tinest (i.e., the MG torque Tmg of the electric motor MG). RT = Tmgest / Tinest (6)

[0077] The estimated MG torque Tmgest in equation (6) is calculated based on the MG rotation speed Nmg detected by the resolver 140 and the applied current Img detected by the current sensor 142. Also, the estimated input torque Tinest in equation (6) is calculated from, for example, the longitudinal acceleration G, the gear ratio γat of the automatic transmission 210, etc.

[0078] The electrical insulation performance determination unit 256 calculates the torque ratio RT based on the formula (6) and determines whether or not oil with low electrical insulation performance is used based on the torque ratio RT. When oil with high electrical insulation performance is used, the amount of current leakage is small, so the estimated MG torque Tmgest and the estimated input torque Tinest are equal or approximately equal. That is, the torque ratio RT is 1.0 or a value close to 1.0. On the other hand, when oil with low electrical insulation performance is used, the amount of leakage increases, so the estimated input torque Tinest becomes smaller than the estimated MG torque Tmgest. That is, the torque ratio RT becomes larger than 1.0, and the lower the electrical insulation performance, the larger the torque ratio RT becomes. Therefore, it is possible to determine whether or not oil with low electrical insulation performance is used based on the torque ratio RT calculated by the formula (6). The control operation of the electrical insulation performance determination unit 156 after the torque ratio RT is calculated is basically the same as that of the electrical insulation performance determination unit 84 in the above-mentioned embodiment, so a description thereof will be omitted. Moreover, the control function of the notification unit 258 is basically the same as that of the notification unit 86 in the embodiment described above, and therefore a description thereof will be omitted.

[0079] As described above, even in a vehicle 200 (electric automobile) that has only an electric motor MG as its power source, it is possible to determine whether or not oil with low electrical insulation performance is being used, based on the electrical insulation performance determination unit 256 and the notification unit 258, and if oil with low electrical insulation performance is being used, the driver can be notified of this.

[0080] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0081] For example, in the above-mentioned first embodiment, the torque ratio RT is calculated based on the torque equation relationship (i.e., the relationship of equation (1)) of the power distribution mechanism 16 (planetary gear device) in the vehicle 8, and the electrical insulation performance of the oil is judged based on the value of the torque ratio RT, but the present invention is not necessarily limited to this embodiment. For example, a torque sensor that detects the MG torque Tmg of each electric motor MG may be provided, and the torque ratio RT (=Tmgest / Tmg) may be calculated from the estimated MG torque Tmgest estimated from the applied current Img of each electric motor MG and the MG torque Tmg detected by the torque sensor, and whether the electrical insulation performance of the oil is low may be judged based on the torque ratio RT.

[0082] In the above-mentioned second embodiment, when the above-mentioned formula (4) is satisfied while the vehicle is traveling, the torque ratio RT is calculated, and the electrical insulation performance of the oil is judged from the torque ratio RT, but the present invention is not necessarily limited to this embodiment. For example, a torque sensor that detects the MG torque Tmg of the electric motor MG may be provided, and the torque ratio RT (=Tmgest / Tmg) may be calculated from the estimated MG torque Tmgest estimated from the applied current Img of the electric motor MG, etc., and the MG torque Tmg detected by the torque sensor, and whether the electrical insulation performance of the oil is low may be judged based on the torque ratio RT.

[0083] In the third embodiment, the estimated input torque Tinest is calculated based on the longitudinal acceleration G, but the present invention is not necessarily limited to this. For example, a torque sensor may be provided to detect the MG torque Tmg of the electric motor MG, and a torque ratio RT (=Tmgest / Tmg) may be calculated from the estimated MG torque Tmgest estimated from the applied current Img of the electric motor MG, etc., and the MG torque Tmg detected by the torque sensor, and whether the electrical insulation performance of the oil is low may be determined based on the torque ratio RT.

[0084] In addition, the automatic transmissions 116, 210 in the above-described embodiments are known planetary gear type automatic transmissions that are configured with one or more planetary gear devices (not shown) and multiple engagement devices CB, but the present invention is not necessarily limited to this. For example, a belt type continuously variable transmission may be used. In other words, the type of automatic transmission is not particularly limited. In addition, an automatic transmission is not necessarily required, and for example, a reduction gear device with a fixed gear ratio may be provided instead of the automatic transmission. Furthermore, the present invention can be applied even to a configuration that does not include an automatic transmission.

[0085] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0086] 8, 100, 200: Vehicles 10, 104, 204: Power transmission device 12: Engine 14: Drive gear (prescribed rotating part) 34: Parts requiring lubrication 36, 102, 202: Drive wheels 84, 156, 256: Electrical insulation performance evaluation section 86, 158, 258: Information Department MG: Electric motor MG1: 1st electric motor (electric motor) MG2: 2nd electric motor (electric motor) RT: Torque ratio K1: First threshold K2: Second threshold

Claims

1. A vehicle including an electric motor that functions as a power source for traveling, a power transmission device that transmits the power of the electric motor to drive wheels, and an engine that functions as a power source separate from the electric motor, an electrical insulation performance determination unit that determines the electrical insulation performance of the oil supplied to the electric motor and the parts requiring lubrication of the power transmission device; a notification unit that notifies a driver of the judgment result of the electrical insulation performance of the oil judged by the electrical insulation performance judgment unit, The electrical insulation performance determination unit determines that the electrical insulation performance of the oil is low when a torque ratio calculated by dividing a sum of an estimated torque of the electric motor and an estimated torque of the predetermined rotating member by an estimated torque of the engine in a running state in which the power of the engine is distributed to the electric motor and a predetermined rotating member mechanically connected to the drive wheels becomes equal to or greater than a first threshold value greater than 1.

0. A vehicle characterized by:

2. The notification unit notifies a driver that oil with low electrical insulation performance is being used when the torque ratio is equal to or greater than the first threshold value.

2. The vehicle of claim 1 .

3. A vehicle comprising an electric motor that functions as a power source for driving, and a power transmission device that transmits the power of the electric motor to drive wheels, an electrical insulation performance determination unit that determines the electrical insulation performance of the oil supplied to the electric motor and the parts requiring lubrication of the power transmission device; a notification unit that notifies a driver of the judgment result of the electrical insulation performance of the oil judged by the electrical insulation performance judgment unit, The electrical insulation performance determination unit determines the electrical insulation performance of the oil from a relationship between an estimated torque of the electric motor calculated based on a current applied to the electric motor and an output torque of the electric motor. A vehicle characterized by:

4. The electrical insulation performance determination unit determines that the electrical insulation performance of the oil is low when a torque ratio calculated by dividing an estimated torque of the electric motor, which is calculated based on a current applied to the electric motor, by an output torque of the electric motor becomes equal to or greater than a first threshold value greater than 1.

0.

4. The vehicle according to claim 3.

5. The notification unit notifies a driver that oil having low electrical insulation performance is being used when the torque ratio is equal to or greater than the first threshold value.

5. The vehicle according to claim 4.

6. When the torque ratio is equal to or greater than a second threshold value that is greater than the first threshold value, a current applied to the electric motor is reduced.

6. A vehicle according to claim 2 or 5.

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