Control device for vehicle

Abstract

To provide a control device for a vehicle that is able to quickly detect the occurrence of abnormal wear of a differential mechanism without disassembly.SOLUTION: Whether an abnormal wear of a differential mechanism has occurred or not is determined based on whether at least one of an absolute value of an amount of change in a first torque ratio which is a value of a ratio of an engine torque estimation value to a first engine torque conversion value based on a first electric motor torque estimation value, and an absolute value of an amount of change in a second torque ratio which is a value of a ratio of an engine torque estimation value to a second engine torque conversion value based on a second electric motor torque estimation value, before and after it is determined that a rotational speed difference between left and right drive wheels is larger than a predetermined speed difference, is greater than a predetermined amount of change. Thus, an electric current leakage from the first electric motor and / or the second electric motor can be detected based on the amount of change in the first torque ratio or the amount of change in the second torque ratio, and a change in the electrical insulation performance of a lubricating oil can be detected. The occurrence of abnormal wear of the differential mechanism can be detected by detecting a rapid decrease in the electrical insulation performance of the lubricating oil.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with a differential mechanism that distributes power from a power source to left and right drive wheels. [Background technology]

[0002] There is a well-known control device for a vehicle that includes a power source and a power transmission device that transmits power from the power source to left and right drive wheels via a differential mechanism. For example, a vehicle driving force distribution control device is described in Patent Document 1. Patent Document 1 discloses that an abnormality in the differential mechanism is detected based on the differential rotation speed. Note that the above "left and right" refers to the left and right relative to the forward and backward traveling direction of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-67891 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the difference in rotation speed between the left and right drive wheels increases due to slippage of one of the drive wheels, that is, when the differential rotation speed of the differential mechanism increases, abnormal wear of the differential mechanism is likely to occur. Such abnormal wear may generate a large amount of metal wear powder in a short time and float in the lubricating oil of the power transmission device. In such a case, for example, the metal wear powder may dissolve, which may reduce the electrical insulation performance of the lubricating oil. This may cause an electrical short circuit or spark in an electric motor cooled by the lubricating oil, which may cause abnormal heat generation of the lubricating oil and a decrease in the power performance of the vehicle. Alternatively, for example, the metal wear powder may get into the sliding parts such as gears and bearings of the power transmission device, causing seizure. This may cause a decrease in the durability of the power transmission device. When abnormal wear of the differential mechanism occurs, it is desirable to detect the occurrence of the abnormal wear as soon as possible. However, if the differential rotation speed of the differential mechanism increases, abnormal wear does not necessarily occur, and it is not possible to determine whether abnormal wear has occurred or not just by detecting that the differential rotation speed of the differential mechanism has increased. Even if abnormal wear occurs in the differential mechanism, it is difficult to detect without disassembly until abnormal heat generation in the lubricating oil, a decrease in the vehicle's power performance, and a noticeable decrease in the durability of the power transmission device are observed.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can quickly detect the occurrence of abnormal wear in a differential mechanism without disassembly. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is a control device for a vehicle including: (a) a power source; and a power transmission device that transmits power from the power source to left and right drive wheels via a differential mechanism, the power source including an engine, the power transmission device including a first electric motor and a power split mechanism having an input element to which the engine is power-transmittably connected, a reaction element to which the first electric motor is power-transmittably connected, and an output element to which the drive wheels are power-transmittably connected, the power source including a second electric motor power-transmittably connected to the drive wheels, the control device comprising: (b) calculating an engine torque estimate based on a control state of the engine; (c) calculating a first electric motor torque estimate based on a control state of the first electric motor; (d) calculating a second electric motor torque estimate based on a control state of the second electric motor; (e) calculating a drive torque estimate based on an acceleration of the vehicle; and (f) comparing the first electric motor torque estimate with the input torque estimate based on a predetermined torque relational equation between each element of the power split mechanism. (g) calculating a second engine torque conversion value by converting the torque estimated value on the output element, which is obtained by subtracting a second electric motor torque conversion value by converting the second electric motor torque estimated value on the output element from the driving torque conversion value by converting the driving torque estimated value on the output element, using the predetermined torque relational expression; (h) calculating a first torque ratio which is a ratio value between the engine torque estimated value and the first engine torque conversion value, and a second torque ratio which is a ratio value between the engine torque estimated value and the second engine torque conversion value; (i) determining whether or not a rotational speed difference between the left and right drive wheels is greater than a predetermined speed difference; and (j) determining whether or not abnormal wear has occurred in the differential mechanism, based on whether at least one of an absolute value of an amount of change in the first torque ratio and an absolute value of an amount of change in the second torque ratio before and after it is determined that the rotational speed difference is greater than the predetermined speed difference is greater than a predetermined change amount. Effect of the Invention

[0007] According to the first aspect of the present invention, whether abnormal wear of the differential mechanism has occurred is determined based on whether at least one of the absolute value of the change in the first torque ratio, which is the ratio value between the engine torque estimate value and the first engine torque equivalent value based on the first electric motor torque estimate value, and the absolute value of the change in the second torque ratio, which is the ratio value between the engine torque estimate value and the second engine torque equivalent value based on the second electric motor torque estimate value, is greater than a predetermined change before and after it is determined that the rotation speed difference between the left and right drive wheels is greater than a predetermined speed difference. As a result, current leakage from the first electric motor and / or the second electric motor can be detected based on the change in the first torque ratio or the change in the second torque ratio, and a change in the electrical insulation performance of the lubricating oil can be detected. By detecting a sudden decrease in the electrical insulation performance of the lubricating oil, it is possible to detect the occurrence of abnormal wear of the differential mechanism. Therefore, the occurrence of abnormal wear of the differential mechanism can be detected quickly without disassembly. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. [Diagram 2] FIG. 2 is a diagram illustrating an example of a configuration of a differential gear. [Diagram 3] 4 is a flowchart illustrating a main part of the control operation of the electronic control device, and is a flowchart illustrating the control operation for quickly detecting the occurrence of abnormal wear in a differential gear without disassembly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0010] Fig. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and is also a diagram illustrating the main parts of a control system for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is equipped with an engine 12, a first electric motor MG1, and a second electric motor MG2. The vehicle 10 also has left and right drive wheels 14 in the forward and backward directions of the vehicle 10, and a power transmission device 16 provided in a power transmission path between a power source and the drive wheels 14. The vehicle 10 is a hybrid vehicle equipped with the engine 12 and the second electric motor MG2 that function as a power source.

[0011] The engine 12 is a known internal combustion engine, and an engine control device 50 provided in the vehicle 10 is controlled by an electronic control device 70 described later, thereby controlling an engine torque Te, which is the torque of the engine 12. The first electric motor MG1 and the second electric motor MG2 are each a rotating electric machine, and are connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10, and an MG1 torque Tmg1, which is the torque of the first electric motor MG1, and an MG2 torque Tmg2, which is the torque of the second electric motor MG2, are controlled by the electronic control device 70 described later, thereby controlling the inverter 52.

[0012] The power transmission device 16 includes, within a case 18, a damper 20, an input shaft 22, a transmission section 24, a compound gear 26, a driven gear 28, a driven shaft 30, a final gear 32, a differential gear 34 (hereinafter referred to as diff 34), a reduction gear 36, etc. The power transmission device 16 also includes a pair of (i.e., left and right) drive shafts 38 connected to the diff 34, etc.

[0013] The compound gear 26 is a rotating body on the output side of the transmission unit 24, and a drive gear 26a is integrally provided on the outer circumferential surface. The final gear 32 meshes with a differential ring gear 34a of the differential 34. The second electric motor MG2 is connected to the drive wheels 14 so as to be capable of transmitting power. The differential 34 is a differential mechanism that distributes power from a power source to the left and right drive wheels 14. When the differential 34 is mounted on the vehicle 10, a part of the lower part in the vertical direction is immersed in the lubricating oil FLD stored vertically below the case 18. The lubricating oil FLD is used to lubricate each part of the power transmission device 16 and to cool each of the first electric motor MG1 and the second electric motor MG2. The lubricating oil FLD is sprayed to each part by the scooping up by the differential ring gear 34a, the pressure of an oil pump (not shown), the centrifugal force caused by the rotation of the shaft, and the like.

[0014] The power transmission device 16 transmits the power output from the engine 12 to the driven gear 28 via the transmission unit 24. The power transmission device 16 also transmits the power output from the second electric motor MG2 to the driven gear 28 via a reduction gear 36. The power transmission device 16 transmits the power transmitted to the driven gear 28 to the left and right drive wheels 14 sequentially via a driven shaft 30, a final gear 32, a differential 34, left and right drive shafts 38, etc.

[0015] The transmission unit 24 includes a first electric motor MG1 and a planetary gear set 40. The planetary gear set 40 is a known single-pinion type planetary gear set including a sun gear S, a carrier CA, a ring gear R, and a plurality of pinions P. The carrier CA is connected to the input shaft 22 and is an input element to which the engine 12 is connected so as to be capable of transmitting power. The sun gear S is connected to the first electric motor MG1 and is a reaction element to which the first electric motor MG1 is connected so as to be capable of transmitting power. The ring gear R is integrally provided on the inner peripheral surface of the compound gear 26 and is an output element to which the drive wheels 14 are connected so as to be capable of transmitting power. The planetary gear set 40 is a power split mechanism that mechanically splits the power of the engine 12 input to the carrier CA to the sun gear S (first electric motor MG1) and the ring gear R (drive gear 26a).

[0016] In the transmission unit 24, the MG1 torque Tmg1, which is a reaction torque of the negative torque generated by the first electric motor MG1, is input to the sun gear S in response to the engine torque Te, which is a positive torque, input to the carrier CA. As a result, a positive engine direct torque Td (= Te / (1+ρ) = -(1 / ρ) × Tmg1) appears in the ring gear R during positive rotation. The combined torque of the engine direct torque Td and the MG2 torque Tmg2 is transmitted to the drive wheels 14 as the drive torque Tr. At this time, the generated power by the first electric motor MG1 is supplied to the battery 54 and the second electric motor MG2. The above "ρ" is the gear ratio of the planetary gear set 40 (= number of teeth of the sun gear / number of teeth of the ring gear). The transmission unit 24 is a known electric continuously variable transmission in which the differential state of the planetary gear set 40 is controlled by controlling the operating state of the first electric motor MG1 with respect to the engine torque Te.

[0017] Fig. 2 is a diagram illustrating an example of the configuration of the differential 34. Fig. 2(a) is an overall view of the differential 34, and Fig. 2(b) is an exploded view of the differential 34 before the members such as the differential side gear 34c housed in the differential case 34b are assembled. In Fig. 2, the differential 34 houses a pair of differential side gears 34c, a pair of differential pinions 34d, a pinion shaft 34e, and a differential washer 60 inside the differential case 34b. The differential 34 has a differential ring gear 34a integrally connected to the outside of the differential case 34b.

[0018] The differential case 34b is formed with a bore portion 34b1 which is a through hole into which the drive shaft 38 is fitted so as to be rotatable relative to the differential case 34b. The differential case 34b is formed with a shaft hole 34b2 which is a through hole into which the pinion shaft 34e is fitted so as not to be rotatable relative to the differential case 34b. The differential side gear 34c has a through hole into which the drive shaft 38 is fitted so as not to be rotatable relative to the differential case 34b, and has spline teeth formed on an inner peripheral surface 34c1 of the through hole into which the drive shaft 38 is fitted so as not to be rotatable relative to the differential case 34b.

[0019] In the differential 34, when the left and right drive wheels 14 are in a differential state with a difference in rotation speed, there are some parts where the members slide against each other. The differential washer 60 is an annular washer interposed between the sliding members in the differential 34. The differential washer 60 includes, for example, a pinion washer 62 and a side gear washer 64. The pinion washer 62 is interposed between the sliding members, that is, the differential case 34b and the differential pinion 34d. The side gear washer 64 is interposed between the sliding members, that is, the differential case 34b and the differential side gear 34c. Other sliding members in the differential 34 include the members between the differential pinion 34d and the pinion shaft 34e, and the members between the differential case 34b (bore portion 34b1) and the drive shaft 38.

[0020] The vehicle 10 is equipped with an electronic control device 70 including a control device for the vehicle 10 that performs current leakage detection control. The electronic control device 70 is configured to include a so-called microcomputer equipped with, for example, a CPU, a RAM, a ROM, an input / output interface, and the like.

[0021] The electronic control device 70 receives various signals based on values ​​detected by various sensors provided in the vehicle 10 (for example, an engine state detection sensor 80, a ring gear rotation speed sensor 82, an output rotation speed sensor 84, a left wheel speed sensor 86, a right wheel speed sensor 88, an MG1 rotation speed sensor 90, an MG2 rotation speed sensor 92, a first current sensor 94, a second current sensor 96, an acceleration sensor 98, etc.) and outputs various signals (for example, signals indicating the control state of the engine 12 (engine rotation speed Ne, intake air amount Qair, intake air The electronic control device 70 supplies various signals to the vehicle 10, such as the temperature Tair, the fuel injection amount M, the ignition timing Tig, the ring gear rotation speed Nrg which is the rotation speed of the ring gear R of the planetary gear device 40, the output rotation speed No which is the rotation speed of the differential ring gear 34a corresponding to the vehicle speed V, the left wheel speed Nwl which is the rotation speed of the left drive wheel 14, the right wheel speed Nwr which is the rotation speed of the right drive wheel 14, the MG1 rotation speed Nmg1, the MG2 rotation speed Nmg2, the MG1 applied current Img1, the MG2 applied current Img2, and the longitudinal acceleration G. The electronic control device 70 outputs various command signals (e.g., engine control command signal Se, MG control command signal Smg, etc.) to each device (e.g., engine control device 50, inverter 52, etc.) provided in the vehicle 10.

[0022] However, when the wheel speed difference ΔNw (=|Nwl-Nwr|), which is the difference between the rotational speeds of the left and right drive wheels 14, i.e., the difference between the left wheel speed Nwl and the right wheel speed Nwr, becomes large, that is, when the differential rotational speed Ndiff, which is the differential rotational speed of the differential 34, becomes high, abnormal wear is likely to occur in the sliding parts of the differential 34. Metal wear powder generated by such abnormal wear reduces the electrical insulation performance of the lubricating oil FLD. In this embodiment, the occurrence of abnormal wear in the differential 34 is detected by performing current leakage detection control that detects current leaking (electric leakage) from the first electric motor MG1 and / or the second electric motor MG2.

[0023] FIG. 3 is a flowchart illustrating the main control operations of the electronic control unit 70, which are for quickly detecting the occurrence of abnormal wear in the differential 34 without disassembly, and which are executed, for example, repeatedly.

[0024] 3, the electronic control device 70 judges whether or not the vehicle is in a predetermined driving mode. In the current leakage detection control, the engine torque Te converted from the MG1 torque Tmg1 and the MG2 torque Tmg2 is compared with the engine torque Te estimated from the control state of the engine 12. Therefore, when the vehicle is in an engine driving mode in which the transmission unit 24 is operated as an electric continuously variable transmission while the engine 12 is in a driving state and accelerates / runs steadily, the MG1 rotation speed Nmg1 is in a forward rotation (i.e., the vehicle is in a power generating state), and the vehicle is in a driving state in which no power is exchanged with the battery 54, the vehicle is judged to be in the predetermined driving mode.

[0025] If the determination in S10 is affirmative, in S20, the electronic control unit 70 starts current leakage detection control. Next, in S30, the electronic control unit 70 calculates the engine torque estimate value Tee based on the control state of the engine 12. The electronic control unit 70 calculates the engine torque estimate value Tee by applying the engine rotation speed Ne, the intake air amount Qair, the intake air temperature Tair, the fuel injection amount M, and the ignition timing Tig to, for example, a predetermined relationship (map or formula).

[0026] Next, in S40, the electronic control device 70 calculates an MG1 torque estimate value Tmg1e, which is a first motor torque estimate value, based on the control state of the first electric motor MG1, calculates an MG2 torque estimate value Tmg2e, which is a second motor torque estimate value, based on the control state of the second electric motor MG2, and calculates a driving torque estimate value Tre based on the longitudinal acceleration G, which is the acceleration of the vehicle 10. The electronic control device 70 calculates the MG1 torque estimate value Tmg1e, for example, by applying a signal (MG1 rotation speed Nmg1, MG1 applied current Img1) representing the control state of the first electric motor MG1 to a predetermined relationship. The electronic control device 70 calculates the MG2 torque estimate value Tmg2e, for example, by applying a signal (MG2 rotation speed Nmg2, MG2 applied current Img2) representing the control state of the second electric motor MG2 to a predetermined relationship. The driving torque estimate value Tre corresponds to a differential shaft torque estimate value Tdiffe, which is a torque estimate value on the differential ring gear 34a. The electronic control device 70 calculates the differential shaft torque estimate value Tdiffe by applying the longitudinal acceleration G to a predetermined relationship, for example. In addition, in S40, the electronic control device 70 calculates a ring gear torque estimate value Trge (=Tdiffe / γ1-Tmg2e / γ2), which is a torque estimate value on the ring gear R, by subtracting a second electric motor torque equivalent value (=Tmg2e / γ2) obtained by converting the MG2 torque estimate value Tmg2e onto the ring gear R from a driving torque equivalent value (=Tdiffe / γ1) obtained by converting the differential shaft torque estimate value Tdiffe onto the ring gear R of the planetary gear device 40. "γ1" corresponds to a gear ratio mechanically defined between the ring gear R and the differential ring gear 34a, and is the same value as the ratio (=Nrg / No) between the ring gear rotation speed Nrg and the output rotation speed No, which is the rotation speed of the differential ring gear 34a. "γ2" corresponds to a gear ratio mechanically defined between the ring gear R and the second electric motor MG2, and is equal to the ratio between the ring gear rotation speed Nrg and the MG2 rotation speed Nmg2 (=Nrg / Nmg2). Note that the ring gear torque estimate Trge can be calculated with even greater accuracy by taking into account other factors such as the temperature of the lubricating oil FLD.

[0027] Next, in S50, the electronic control unit 70 calculates a first torque ratio Rt1 and a second torque ratio Rt2. The electronic control unit 70 calculates a first engine torque conversion value Tec1 (=-(1+ρ) / ρ×Tmg1e) by converting the MG1 torque estimation value Tmg1e onto the carrier CA of the planetary gear set 40 using a predetermined torque relational expression (Td=Te / (1+ρ)=-(1 / ρ)×Tmg1) between the elements of the planetary gear set 40. The electronic control unit 70 calculates a second engine torque conversion value Tec2 (=Trge×(1+ρ)) by converting the ring gear torque estimation value Trge onto the carrier CA using a predetermined torque relational expression (Td=Te / (1+ρ)=-(1 / ρ)×Tmg1). The electronic control device 70 calculates a first torque ratio Rt1 (=Tec1 / Tee), which is the ratio between the engine torque estimated value Tee and the first engine torque conversion value Tec1, and a second torque ratio Rt2 (=Tec2 / Tee), which is the ratio between the engine torque estimated value Tee and the second engine torque conversion value Tec2.

[0028] When the electrical insulation performance of the lubricating oil FLD is good, the MG1 torque estimate value Tmg1e and the MG2 torque estimate value Tmg2e are equal or approximately equal to the actual values. When there is no current leakage from the first motor MG1 and the second motor MG2 or the current leakage from the second motor MG2 can be ignored, the first torque ratio Rt1 and the second torque ratio Rt2 are each "1". On the other hand, when the electrical insulation performance of the lubricating oil FLD is deteriorated, the current leakage from the first motor MG1 and / or the second motor MG2 increases, and the MG1 torque estimate value Tmg1e and / or the MG2 torque estimate value Tmg2e calculated from the applied current increase. However, since the actual values ​​of the MG1 torque Tmg1 and the MG2 torque Tmg2 do not change, the engine torque estimate value Tee reflecting the actual value of the engine torque Te that is in balance with the actual value of the motor torque does not change either. As a result, the first torque ratio Rt1 becomes larger than "1" and / or the second torque ratio Rt2 becomes smaller than "1". By periodically recording the first torque ratio Rt1 and the second torque ratio Rt2, it becomes possible to detect current leakage from the first electric motor MG1 and / or the second electric motor MG2 and changes in the electrical insulation performance of the lubricant FLD. Although it is possible to detect changes in the electrical insulation performance of the lubricant FLD by detecting deviations from "1" in the values ​​of the first torque ratio Rt1 and the second torque ratio Rt2 themselves, in this embodiment, taking into account aging and replacement of the lubricant FLD, changes in the electrical insulation performance of the lubricant FLD are detected by comparing the first torque ratio Rt1 and the second torque ratio Rt2 before and after an overloaded differential rotation of the differential 34.

[0029] Therefore, following S50, in S60, the electronic control device 70 judges whether the wheel speed difference ΔNw, i.e., the differential rotation speed Ndiff, is greater than a predetermined speed difference Nf. The predetermined speed difference Nf is, for example, a threshold value determined in advance for judging that an overloaded differential rotation occurs to the extent that metal wear powder is generated due to abnormal wear in the sliding portion of the differential 34. If the judgment in S60 is negative, the electronic control device 70 judges in S70 whether the elapsed time since the previous judgment in S60 was positive is within a predetermined time TMf. Even if an overloaded differential rotation of the differential 34 occurs, the electrical insulation performance of the lubricant FLD may not decrease immediately, so even if the overloaded differential rotation ceases and the judgment in S60 is negative, the first torque ratio Rt1 and the second torque ratio Rt2 before and after the overloaded differential rotation are compared within the predetermined time TMf. The predetermined time TMf is, for example, a threshold value determined in advance as a waiting time during which the electrical insulation performance of the lubricant FLD may decrease after an overloaded differential rotation of the differential 34 occurs.

[0030] If the determination in S60 is positive, or if the determination in S70 is positive, in S80, the electronic control device 70 determines whether abnormal wear of the differential 34 has occurred based on whether the absolute value of the amount of change in the first torque ratio Rt1 before and after it is determined that the differential rotation speed Ndiff is greater than the predetermined speed difference Nf is greater than a predetermined change amount A, or whether the absolute value of the amount of change in the second torque ratio Rt2 before and after it is determined that the differential rotation speed Ndiff is greater than the predetermined speed difference Nf is greater than a predetermined change amount B. The predetermined change amount A and the predetermined change amount B are each a predetermined threshold value for determining that the amount of change in the torque ratio is large enough to determine that abnormal wear of the differential 34 has occurred, for example.

[0031] If the determination in S80 is positive, in S90, the electronic control unit 70 notifies the driver that abnormal wear has occurred in the differential 34. For example, the electronic control unit 70 may turn on a warning light, generate a warning sound, or display on a monitor to notify the driver that abnormal wear has occurred in the differential 34. The content displayed on the monitor may be, for example, a message urging the driver to perform maintenance or inspection of the differential 34, a message urging the driver to replace some parts of the differential 34, or a message urging the driver to replace the lubricating oil FLD.

[0032] If the determination in S10 is negative, or if the determination in S70 is negative, or if the determination in S80 is negative, in S100, the electronic control unit 70 does not start current leakage detection control, or ends the current leakage detection control that is being executed, and performs normal control such as engine control or MG control.

[0033] As described above, according to this embodiment, current leakage from the first electric motor MG1 and / or the second electric motor MG2 can be detected based on the amount of change in the first torque ratio Rt1 or the amount of change in the second torque ratio Rt2, and the change in the electrical insulation performance of the lubricant FLD can be detected. By detecting a sudden decrease in the electrical insulation performance of the lubricant FLD, it is possible to detect the occurrence of abnormal wear of the differential 34. Therefore, the occurrence of abnormal wear of the differential 34 can be detected quickly without disassembly.

[0034] Although the embodiment of the present invention has been described in detail above with reference to the drawings, what has been described above is merely one embodiment, and the present invention can be embodied in other forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0035] 10: vehicle 12: engine (power source) 14: drive wheels 16: power transmission device 34: differential gear (differential mechanism) 40: planetary gear device (power split mechanism) CA: carrier (input element) R: ring gear (output element) S: sun gear (reaction element) 70: electronic control device (control device) MG1: first electric motor MG2: second electric motor (power source)

Claims

[Claim 1] A control device for a vehicle including a power source and a power transmission device that transmits power from the power source to left and right drive wheels via a differential mechanism, the power source including an engine, the power transmission device including a first electric motor and a power split mechanism having an input element to which the engine is power-transmittably connected, a reaction element to which the first electric motor is power-transmittably connected, and an output element to which the drive wheels are power-transmittably connected, the power source including a second electric motor power-transmittably connected to the drive wheels, Calculating an engine torque estimate based on a control state of the engine; Calculating a first electric motor torque estimate value based on a control state of the first electric motor; Calculating a second electric motor torque estimate value based on a control state of the second electric motor; Calculating a drive torque estimate based on the acceleration of the vehicle; calculating a first engine torque conversion value by converting the first electric motor torque estimated value into an input torque value using a predetermined torque relational expression between each element of the power split mechanism; calculating a second engine torque conversion value obtained by converting the torque estimated value on the output element onto the input element using the predetermined torque relational expression, the second engine torque conversion value being obtained by subtracting a second electric motor torque conversion value obtained by converting the second electric motor torque estimated value onto the output element from a driving torque conversion value obtained by converting the driving torque estimated value onto the output element; calculating a first torque ratio which is a ratio value between the engine torque estimation value and the first engine torque conversion value, and a second torque ratio which is a ratio value between the engine torque estimation value and the second engine torque conversion value, determining whether a rotational speed difference between the left and right drive wheels is greater than a predetermined speed difference; a control device for a vehicle, characterized in that it is determined whether or not abnormal wear has occurred in the differential mechanism based on whether or not at least one of the absolute value of the amount of change in the first torque ratio and the absolute value of the amount of change in the second torque ratio before and after it is determined that the rotational speed difference is greater than the predetermined speed difference is greater than a predetermined change amount.

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