JP2019069721A - Controller for four-wheel drive vehicle - Google Patents

Abstract

To provide a controller for four-wheel drive vehicle that suppresses circulation torque acting on occurrence of anchorage failure to an electronic control coupling.SOLUTION: Since a controller includes a clutch engagement control part 104 which controls a first clutch 24 and a second clutch 32 into a disconnection state respectively when an anchorage failure diagnostic part 106 diagnoses occurrence of anchorage failure to an electronic control coupling 48, a clutch engagement control part 104 controls the first clutch 24 and second clutch 32 into the disconnection state respectively if the occurrence of anchorage failure to the electronic control coupling 48 is diagnosed. Consequently, if the anchorage failure occurs to the electronic control coupling 48, power transmission between an engine 12 and a power transmission path 52 and power transmission between the power transmission path 52 and rear wheels 16L, 16R are cut of, respectively, so circulation torque acting owing to the occurrence of anchorage failure to the electronic control coupling 48 is suitably suppressed.SELECTED DRAWING: Figure 2

Description

  In the four-wheel drive vehicle according to the present invention, in the four-wheel drive vehicle, part of the power of the drive power source is transmitted to the auxiliary drive wheel via the power transmission path including the electronically controlled coupling during four-wheel drive traveling. The present invention relates to a technology for suitably suppressing the circulating torque that acts due to the occurrence of a failure.

  (A) a pair of left and right main driving wheels to which the power of the driving power source is transmitted, and (b) part of the power of the driving power source during four-wheel drive traveling via a power transmission path including an electronic control coupling. (C) a first disconnecting device for connecting and disconnecting power transmission between the driving power source and the power transmission path, (d) the power transmission path and the sub-drive A four-wheel drive vehicle is known which has a second disconnecting device connecting and disconnecting power transmission between wheels. For example, a four-wheel drive vehicle described in Patent Document 1 is that. In the four-wheel drive vehicle of Patent Document 1, the power transmission path is formed by the main drive wheel and the auxiliary by disconnecting the first connection device and the second connection device during two-wheel drive travel. It is separated from the drive wheels to reduce power loss during two-wheel drive travel.

JP, 2016-203875, A

  By the way, in a four-wheel drive vehicle like patent document 1, if a sticking failure arises in the said electronic control coupling at the time of four-wheel drive travel, between the main drive wheel and the said subdrive wheel like the time of vehicle turning etc. When differential rotation occurs in the vehicle, there is a problem that the circulating torque for the vehicle ground contact reaction acts on the power transmission system of the four-wheel drive vehicle. In addition, when the circulating torque acts on the power transmission system of the four-wheel drive vehicle, the operability of the vehicle is reduced, or unnecessary torque is inputted to the components constituting the power transmission system of the four-wheel drive vehicle. Problems arise.

  The present invention has been made against the background described above, and an object of the present invention is to provide a control device for a four-wheel drive vehicle that suppresses a circulation torque that acts by causing a sticking failure in the electronic control coupling. It is to provide.

  According to the first aspect of the present invention, (a) a pair of left and right main driving wheels to which the power of the driving power source is transmitted, and a part of the power of the driving power source during the four-wheel drive traveling are electronically controlled couplings. A pair of left and right auxiliary drive wheels transmitted via a power transmission path, a first disconnection device for connecting and disconnecting power transmission between the drive power source and the power transmission path, the power transmission path and the auxiliary A control device of a four-wheel drive vehicle having a second connection / disconnection device for connecting and disconnecting power transmission with a drive wheel, and (b) diagnosing whether or not a sticking failure occurs in the electronic control coupling And (c) at least one of the first disconnection device and the second disconnection device is disconnected when it is diagnosed by the failure diagnosis unit that a sticking failure has occurred in the electronic control coupling. And a cutting device control unit that controls the state.

  According to the first aspect of the invention, when it is diagnosed by the failure diagnosis unit that a sticking failure has occurred in the electronic control coupling, at least one of the first disconnection device and the second disconnection device is disconnected. Since the control unit for controlling the connection and disconnection is included, when it is diagnosed that a sticking failure occurs in the electronic control coupling, the control unit for the connection and disconnection controls the first connection and disconnection device and the second connection and disconnection device. At least one is controlled to be disconnected. For this reason, when a sticking failure occurs in the electronic control coupling, power transmission between the driving power source and the power transmission path, and power transmission between the power transmission path and the auxiliary drive wheel Since at least one of the power transmissions is disconnected, the circulation torque acting by the occurrence of the sticking failure in the electronic control coupling is suitably suppressed.

FIG. 1 is a skeleton view schematically illustrating the configuration of a four-wheel drive vehicle to which the present invention is preferably applied. It is a functional block diagram explaining the principal part of the control function with which the electronic control apparatus of the four-wheel drive vehicle of FIG. 1 was equipped. FIG. 7 is a view showing an example of a sticking failure detection value calculation map for calculating a sticking failure detection value used to diagnose a sticking failure in the sticking failure diagnosis unit of FIG. 2 from an actual steering angle. In the electronic control unit shown in FIG. 1, power transmission between the engine and the power transmission path and power transmission between the power transmission path and the rear wheel are respectively connected by the first clutch and the second clutch in a four-wheel drive state FIG. 10 is a flowchart illustrating an example of control operation of the first clutch and the second clutch when a sticking failure occurs in the electronic control coupling while traveling.

  In the embodiment of the present invention, the failure diagnosis unit may be configured such that power transmission between the driving power source and the power transmission path, and power transmission between the power transmission path and the sub drive wheel are the first disconnection. The power transmission between the first rotary element on the main drive wheel side and the second rotary element on the sub drive wheel side of the electronic control coupling is cut off In the state, when the differential rotation between the first rotating element and the second rotating element becomes equal to or less than the sticking failure detection value set in advance based on the actual steering angle at the time of turning of the vehicle, sticking failure to the electronic control coupling To diagnose that arose. By this, it is possible to suitably diagnose whether or not a sticking failure has occurred in the electronic control coupling in the failure diagnosis unit.

  In the embodiment of the present invention, the disconnection device control unit is diagnosed by the failure diagnosis unit that a sticking failure has occurred in the electronic control coupling, and the first disconnection occurs when the four-wheel drive vehicle is stopped. Since at least one of the connecting device and the second disconnection device is controlled to be in the disconnection state, for example, the first failure diagnosis unit diagnoses that the sticking failure has occurred in the electronic control coupling by the failure diagnosis unit. Vehicle operability is improved as compared to controlling at least one of the disconnection device and the second disconnection device in the disconnection state.

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

  FIG. 1 is a skeleton view schematically illustrating the configuration of a four-wheel drive vehicle 10 to which the present invention is preferably applied. In FIG. 1, a four-wheel drive vehicle 10 uses a engine 12 as a driving power source, and transmits a power of the engine 12 to left and right front wheels 14L and 14R corresponding to main drive wheels. An FF-based four-wheel drive is provided that includes a second power transmission path that transmits power to the left and right rear wheels 16L, 16R corresponding to the auxiliary drive wheels. In the two-wheel drive state of the four-wheel drive vehicle 10, the power transmitted from the engine 12 through the automatic transmission 18 is transmitted to the left and right front wheels 14L, 14R through the front wheel differential unit 20 and the left and right axles 22L, 22R. . In this two-wheel drive state, at least the first clutch (first connection and disconnection device) 24 is released, and power is not transmitted to the transfer 26, the propeller shaft 28, and the rear wheel differential unit 30 and the rear wheels 16L and 16R. . However, in the four-wheel drive state of the four-wheel drive vehicle 10, in addition to the two-wheel drive state, the first clutch 24 and the second clutch (second disconnection device) 32 are both engaged, and the transfer 26 and propeller Power from the engine 12 is transmitted to the shaft 28 and the rear wheel differential unit 30 and the rear wheel 16. The transfer 26 is for distributing a part of the power of the engine 12 to the rear wheel differential unit 30, that is, the rear wheels 16L and 16R via a power transmission path 52 including an electronic control coupling 48 described later. Further, although not shown in FIG. 1, a torque converter or a clutch, which is a fluid transmission device, is provided between the engine 12 and the automatic transmission 18.

  The front wheel differential unit 20 is rotatably provided about the first rotation axis C1, and is in a ring gear 20r meshing with the output gear 18a of the automatic transmission 18, a differential case (differential case) 20c fixed thereto, and a differential case 20c. The differential gear mechanism 20d is accommodated, and power is transmitted to the left and right axles 22L, 22R of the front wheels 14L, 14R while allowing their differential rotation. The differential case 20 c is formed with an inner peripheral fitting tooth 38 to be fitted with an outer peripheral fitting tooth 36 formed at the axial end of the first rotating member 34 of the transfer 26.

  The transfer 26 includes a first rotating member 34 having an outer peripheral fitting tooth 36 formed thereon, and a second rotating member 40 having a ring gear 40r formed thereon for meshing with the driven pinion 44 for transmitting power to the rear wheels 16L and 16R. , And the first clutch 24. Further, at an end portion of the first rotating member 34 on the front wheel 14R side in the direction of the first rotation axis C1, clutch teeth 42 constituting the first clutch 24 are formed. Further, at an end portion of the second rotating member 40 on the front wheel 14R side in the direction of the first rotation axis C1, clutch teeth 46 constituting the first clutch 24 are formed. The driven pinion 44 is connected to the front end of the propeller shaft 28 so as to transmit power, and the rear end of the propeller shaft 28 is connected to the drive pinion 50 so as to transmit power via an electronic control coupling 48 described later. .

  The first clutch 24 selectively disconnects the power transmission between the first rotary member 34 and the second rotary member 40, that is, the power transmission between the engine 12 and the power transmission path 52 including the electronic control coupling 48. It is a connecting / disconnecting device for connecting or disconnecting / connecting power transmission, and is always meshed with the clutch teeth 42 formed on the first rotating member 34 and capable of relative movement in the direction of the first rotation axis C1 and in the direction of the first rotation axis C1. The first movable sleeve 54 having the first movable sleeve 54 formed at the first meshing position and the first non-meshing position has the first movable sleeve 54 formed with the inner peripheral teeth 54a that can also mesh with the clutch teeth 46 formed on the second rotating member 40 by movement. And a first actuator 56 which is driven in the direction of the first rotation axis C1. Note that, in the first meshing position, the first movable sleeve 54 has the inner peripheral teeth 54a of the first movable sleeve 54 meshing with the clutch teeth 42 and the inner peripheral teeth 54a of the first movable sleeve 54 meshing with the clutch teeth 46 as well. The first non-engagement position is such that the inner peripheral teeth 54a of the first movable sleeve 54 mesh with the clutch teeth 42 and the inner peripheral teeth 54a of the first movable sleeve 54 are at a predetermined position in the direction of the first rotation axis C1. Is a predetermined position in the direction of the first rotation axis C1 of the first movable sleeve 54 that does not engage with the clutch teeth 46. The first actuator 56 selectively sets the first movable sleeve 54 to the first meshing position and the first non-meshing position by a first current I1 supplied from an electronic control unit (control unit) 100 described later. When the first movable sleeve 54 is moved to the first meshing position by the first actuator 56, the first clutch 24 is connected to the power transmission between the engine 12 and the power transmission path 52. Connection state. In addition, when the first movable sleeve 54 is moved to the first non-engaging position by the first actuator 56, the first clutch 24 is disconnected when power transmission between the engine 12 and the power transmission device 52 is disconnected. It will be (off state). The power transmission path 52 includes, for example, a propeller shaft 28, a driven pinion 44, an electronic control coupling 48, a drive pinion 50, and the like, and part of the power of the engine 12 to the rear wheels 16L and 16R during four-wheel drive traveling. It is a power transmission path to be transmitted.

  The electronically controlled coupling 48 includes a first rotating element 48a on the side of the front wheels 14L and 14R coupled to the propeller shaft 28 in a power transmission manner, and a rear wheel 16L and 16R on the side coupled to the drive pinion 50 in a power transmission manner. A second rotating element 48b, although not shown, is provided with an electrically controllable actuator including an electromagnetic coil and a ball cam, and a wet multi-plate clutch whose frictional force is adjusted by the actuator, the electromagnetic coil The power transmitted to the rear wheels 16L and 16R is adjusted by the magnetic force generated by the energization. That is, the electronic control coupling 48 transmits to the rear wheels 16L and 16R the transmission torque according to the third current I3 supplied from the electronic control device 100 to the electromagnetic coil provided in the actuator. When the third current I3 is not supplied from the electronic control unit 100 to the electromagnetic coil and the electronic control coupling 48 is in the non-operation state (OFF state), the first rotation element 48a and the second rotation element 48b Power transmission between them is cut off.

  The rear wheel differential unit 30 selectively cuts off the power transmission between the power transmission path 52 and the rear wheels 16L and 16R, that is, the power transmission between the ring gear 58 meshing with the drive pinion 50 and the differential case (differential case) 60. Alternatively, the power transmitted from the engine 12 to the differential case 60 in a state in which the second clutch 32, which is a mesh type dog clutch (connection / disengagement device) for connecting or disconnecting power transmission, is engaged A differential gear 64 is provided to allow differential rotation to the left and right rear wheels 16L, 16R. The differential gear device 64 is connected to the differential case 60 rotatably supported about the second rotation axis C 2 and to a pair of axles 62 L and 62 R connected to the rear wheels 16 L and 16 R. A pair of side gears 66 rotatably supported by the differential case 60 about the second rotational axis C2 in a mutually opposing state, and the differential case 60 rotatably about the third rotational axis C3 orthogonal to the second rotational axis C2. And a pair of pinions 68 supported. In addition, a cylindrical portion 58 a that protrudes in a cylindrical shape in the direction of the second rotation axis C 2 is integrally formed on the inner peripheral portion of the ring gear 58. The differential case 60 is formed with a cylindrical shaft 60a projecting from the differential case 60 toward the rear wheel 16L, that is, toward the inside of the cylindrical portion 58a of the cylindrical ring gear 58. The tip of the cylindrical shaft 60a is formed The portion is disposed inside the cylindrical portion 58 a of the cylindrical ring gear 58.

  As shown in FIG. 1, the second clutch 32 is formed on the outer peripheral surface of the inner peripheral meshing teeth 58 b formed on the inner peripheral surface of the cylindrical portion 58 a of the ring gear 58 and the tip of the cylindrical shaft 60 a of the differential case 60. The outer case 70 is formed in the differential case 60 by movement in the second rotational axis C2 direction, and the outer peripheral tooth 70a and always meshed with the outer peripheral engagement tooth 60b and the inner peripheral engagement tooth 58b formed in the ring gear 58 relative to the second rotational axis C2. The second movable sleeve 70 having the inner peripheral teeth 70b capable of meshing with the outer peripheral meshing teeth 60b and the second movable sleeve 70 are driven in the direction of the second rotation axis C2 between the second meshing position and the second non meshing position. It is a dog clutch of the meshing type provided with the second actuator 72. At the second meshing position, the outer peripheral teeth 70a of the second movable sleeve 70 mesh with the inner peripheral meshing teeth 58b of the ring gear 58, and the inner peripheral teeth 70b of the second movable sleeve 70 mesh with the outer peripheral meshing teeth 60b of the differential case 60. The second non-engagement position of the second movable sleeve 70 is in a predetermined position in the direction of the second rotation axis C2. The second non-engagement position is such that the outer peripheral teeth 70a of the second movable sleeve 70 mesh with the inner peripheral engagement teeth 58b of the ring gear 58 The second movable sleeve 70 is at a predetermined position in the direction of the second rotation axis C2 of the second movable sleeve 70 such that the inner peripheral teeth 70b of the second movable sleeve 70 do not mesh with the outer peripheral meshing teeth 60b of the differential case 60. The second actuator 72 is an actuator that selectively moves the second movable sleeve 70 between the second meshing position and the second non-meshing position by the second current I2 supplied from the electronic control device 100. When the second movable sleeve 70 is moved to the second meshing position by the second actuator 72, the second clutch 32 is connected such that power transmission between the power transmission path 52 and the rear wheels 16L and 16R is connected. It becomes. Further, when the second movable sleeve 70 is moved to the second non-engaging position by the second actuator 72, the power transmission between the power transmission device 52 and the rear wheels 16L and 16R is cut off. It will be in the disconnection state (off state). The ball cam 74, the annular electromagnet 76, the auxiliary clutch 78, the ratchet mechanism 80, the spring 82, and the like provided in the second actuator 72 are known techniques as shown in, for example, Patent Document 1 described above. Description of the specific structure and operation will be omitted.

  In the four-wheel drive vehicle 10 configured as described above, when, for example, the four-wheel drive travel mode is selected by the electronic control unit 100, the first movable sleeve 54 is moved by the first actuator 56 in the first clutch 24. It is moved to the meshing position, power transmission between the engine 12 and the power transmission path 52 is connected, and the second movable sleeve 70 is moved to the second meshing position by the second actuator 72 in the second clutch 32. And the power transmission between the power transmission path 52 and the rear wheels 16L, 16R is connected, so that the four-wheel drive state in which power is transmitted from the engine 12 to the left and right front wheels 14L, 14R and the left and right rear wheels 16L, 16R is It is formed. When, for example, the two-wheel drive travel mode is selected in the electronic control unit 100, the first movable sleeve 54 is moved to the first non-engaging position by the first actuator 56 in the first clutch 24 to power the engine 12 and motive power. The power transmission with the transmission path 52 is cut off, and the second movable sleeve 70 is moved to the second non-engaging position by the second actuator 72 in the second clutch 32 to transmit the power transmission path 52 and the rear wheel 16L. , And 16R are cut off to form a two-wheel drive state in which power is transmitted only from the engine 12 to the left and right front wheels 14L and 14R. In the two-wheel drive state, the first clutch 24 cuts off the power transmission between the engine 12 and the power transmission path 52, and the second clutch 32 cuts between the power transmission path 52 and the rear wheels 16L and 16R. The power transmission path 52, that is, the propeller shaft 28 is disconnected from the left and right front wheels 14L and 14R and the left and right rear wheels 16L and 16R.

  FIG. 2 is a functional block diagram for explaining the main parts of control functions provided in the electronic control unit 100 provided in the four-wheel drive vehicle 10 of FIG. The electronic control unit 100 is configured to include, for example, a so-called microcomputer provided with a CPU, a RAM, a ROM, an input / output interface and the like, and the CPU follows a program stored in advance in the ROM while using a temporary storage function of the RAM. Various control of the four-wheel drive vehicle 10 is executed by performing signal processing. As shown in FIG. 2, the electronic control unit 100 is supplied with various input signals detected by respective sensors provided in the four-wheel drive vehicle 10. For example, a 4WD switching signal 4WDon representing a switch request to the four-wheel drive state from the driver detected by the 4WD switch 84 and a steering angle (steering angle) detected by the steering sensor 86, that is, a steering angle θ (deg) ), A signal representing the vehicle speed V (km / h) detected by the vehicle speed sensor 88, and a rotation speed of the first rotation element 48a of the electronic control coupling 48 detected by the first rotation speed sensor 90. A signal representing N1 (rpm) and a signal representing the rotational speed N2 (rpm) of the second rotating element 48b of the electronic control coupling 48 detected by the second rotational speed sensor 92 are input to the electronic control unit 100. Be done.

  In addition, various output signals are supplied from the electronic control unit 100 to each device provided in the four-wheel drive vehicle 10. For example, the first current I1 supplied to the first actuator 56 to connect and disconnect the connecting and disconnecting device as the first clutch 24 and the second current 72 to connect and disconnect the connecting and disconnecting device as the second clutch 32 And the third current I3 or the like supplied to the actuator of the electronically controlled coupling 48 to control the transmission torque of the electronically controlled coupling 48 from the electronic control device 100 to each portion .

  The vehicle travel state determination unit 102 shown in FIG. 2 determines whether or not the vehicle travel state has become capable of suitably detecting the sticking failure of the electronic control coupling 48, that is, the power between the engine 12 and the power transmission path 52. The power transmission between the transmission and power transmission path 52 and the rear wheels 16L, 16R is connected by the first clutch 24 and the second clutch 32, respectively, and the first rotating element 48a and the second rotating element 48b in the electronic control coupling 48 It is determined whether or not the vehicle is in a turning state with the power transmission between them being disconnected. Note that the above-mentioned sticking failure of the electronic control coupling 48 means that the first rotary element 48a and the second rotary element 48b are integrally when the electronic control coupling 48 is in the non-operation state due to the electronic control coupling 48 for some reason. It is a lock failure of the electronically controlled coupling 48 that is stuck. For example, in the vehicle travel state determination unit 102, the 4WD changeover switch 80 is operated by the driver, and the electronic control device 100 does not supply the third current I3 to the actuator of the electronic control coupling 48, and the electronic control coupling 48 The electronic control cup is in the non-operation state (OFF state) and when the vehicle speed V is equal to or higher than the predetermined speed Y (km / h) and the steering angle θ is equal to or larger than the predetermined angle X (deg). It is determined that the vehicle is in the traveling state where the sticking failure of the ring 48 can be suitably detected. The predetermined speed Y (km / h) and the predetermined angle X (deg) described above are between the front wheels 14L and 14R and the rear wheels 16L and 16R while the vehicle is turning, that is, the first rotating element 48a of the electronic control coupling 48. And the second rotating element 48b easily generate differential rotation, which makes it easy to detect a sticking failure of the electronic control coupling 48, vehicle speed V (km / h) and steering set in advance by experiment etc. It is a turning angle θ (deg). In addition, the clutch engagement control unit 104 controls the first movable sleeve 54 to move to the first meshing position in the first clutch 24 from the electronic control device 100 when the 4WD changeover switch 84 is operated by the driver. The first current I1 is supplied to the first actuator 56 of the first clutch 24, and the second movable sleeve 70 is moved to the second meshing position in the second clutch 32 from the electronic control device 100 to the second clutch 32 The actuator 72 is supplied with the second current I2. As a result, the first clutch 24 and the second clutch 32 transmit the power between the engine 12 and the power transmission path 52 by the clutch engagement control unit 104 and the power between the power transmission path 52 and the rear wheels 16L, 16R. The transmissions are controlled to the connected state respectively connected.

  If it is determined by the vehicle traveling state determination unit 102 that the sticking failure diagnosis unit (failure diagnosis unit) 106 is capable of suitably detecting a sticking failure of the electronic control coupling 48, the adhesion failure diagnosis unit (failure diagnosis unit) 106 switches to the electronically controlled coupling 48. Diagnose whether a sticking failure has occurred. For example, the sticking failure diagnosis unit 106 performs differential rotation (N1-N2) between the rotational speed N1 of the first rotary element 48a and the rotational speed N1 of the second rotary element 48b in the actual electronic control coupling 48, that is, the coupling longitudinal difference If the dynamic rotation speed Ns (rpm) becomes equal to or less than the sticking failure detection value Ns1 (rpm) preset based on the actual steering angle θ1, it is diagnosed that the sticking failure has occurred in the electronically controlled coupling 48. In this embodiment, for example, when the actual steering angle θ1 (see FIG. 3) is detected using the fixation failure detection value calculation map shown in FIG. 3, the coupling fixation failure detection line L1 is used. The sticking failure detection value Ns1 (see FIG. 3), which is the coupling rotational speed differential rotation speed Ns, is calculated. In addition, the line L2 described by the alternate long and short dash line in the fixation failure detection value calculation map of FIG. 3 indicates the non-operation state of the electronic control coupling 48 when the electronic control coupling 48 in which the fixation failure does not occur is used ( The relationship between the steering angle θ at the time of OFF) and the differential rotation speed Ns before and after the coupling is obtained, for example, by experiments. Incidentally, the fixed failure detection value Ns1 becomes lower than the line L2 in the differential rotation speed Ns before and after the steering with respect to the steering angle θ when the electronic control coupling 48 is not operating, and the electronic control coupling 48 The coupling rotational speed Ns is set in advance by experiments etc., which is considered to be that the first rotating element 48 a and the second rotating element 48 b are integrally fixed to increase the possibility of the fixing failure. The coupling sticking failure detection line L1 is a set of sticking failure detection values Ns1 corresponding to the respective steering wheel turning angles θ.

  In the display control unit 108, when the sticking failure diagnosis unit 106 diagnoses that the sticking failure occurs in the electronic control coupling 48, the sticking failure occurs in the electronically controlled coupling 48 in a display device (not shown) provided in the vehicle compartment, for example. Display a warning to inform the driver about

  The clutch engagement control unit 104 is diagnosed by the fixation failure diagnosis unit 106 that the fixation failure has occurred in the electronic control coupling 48, and when the four-wheel drive vehicle 10 is stopped, the first movable sleeve 54 is A first current I1 is supplied from the electronic control unit 100 to the first actuator 56 of the first clutch 24 so as to move to the first non-engagement position, and the second movable sleeve 70 in the second clutch 32 performs the second non-engagement A second current I2 is supplied from the electronic control unit 100 to the second actuator 72 of the second clutch 32 so as to move to the position. As a result, the first clutch 24 and the second clutch 32 transmit the power between the engine 12 and the power transmission path 52 by the clutch engagement control unit 104 and the power between the power transmission path 52 and the rear wheels 16L, 16R. It is controlled in the disconnection state (disconnection state) in which the transmission is disconnected respectively. In addition, when the first clutch 24 and the second clutch 32 are controlled to be in the disconnected state by the clutch engagement control unit 104, the display control unit 108 performs, for example, a two-wheel drive state on a display device (not shown) provided in the vehicle compartment. Output a display to notify the driver that it has become.

  In FIG. 4, in the electronic control unit 100, the power transmission between the engine 12 and the power transmission path 52 and the power transmission between the power transmission path 52 and the rear wheels 16L and 16R are the first clutch 24 and the second clutch, respectively. FIG. 32 is a flowchart illustrating an example of control operation of the first clutch 24 and the second clutch 32 when a sticking failure occurs in the electronic control coupling 48 during traveling in a four-wheel drive state connected by 32. FIG.

  First, in step (hereinafter, step is omitted) S1 corresponding to the function of the vehicle travel state determination unit 102, the vehicle speed V (km / h) of the four-wheel drive vehicle 10 is equal to or higher than a predetermined speed Y (km / h) It is determined whether or not V) Y). When the determination of S1 is negative, the present routine is ended, but when the determination of S1 is positive, S2 corresponding to the function of the vehicle travel state determination unit 102 is executed. In S2, it is determined whether or not the steering angle θ (deg) is equal to or greater than a predetermined angle X (deg) (θ X X). When the determination of S2 is negative, the present routine is ended, but when the determination of S2 is positive, S3 corresponding to the function of the vehicle travel state determination unit 102 is executed. In S3, it is determined whether the third current I3 is not supplied from the electronic control unit 100 to the actuator of the electronic control coupling 48 and the electronic control coupling 48 is in the inoperative state (OFF state). This routine is ended if the determination at S3 is negative, but if the determination at S3 is affirmative, that is, if the vehicle is in a traveling state where the sticking failure of the electronic control coupling 48 can be suitably detected. S4 corresponding to the function of the failure diagnosis unit 106 is executed.

  Next, in S4, it is diagnosed whether a sticking failure has occurred in the electronic control coupling 48 or not. If the determination in S4 is negative, that is, no sticking failure occurs in the electronic control coupling 48, this routine is ended. However, if the determination in S4 is affirmative, the sticking failure in the electronic control coupling 48 occurs. If it has occurred, S5 corresponding to the functions of the clutch engagement control unit 104 and the display control unit 108 is executed. In S5, for example, a warning is displayed on the display device (not shown) provided in the vehicle compartment to notify the driver that the sticking failure has occurred in the electronic control coupling 48, and then the four-wheel drive vehicle 10 is stopped. The one clutch 24 and the second clutch 32 are controlled to be in the disconnected state, respectively.

  As described above, according to the electronic control unit 100 of the four-wheel drive vehicle 10 of the present embodiment, when it is determined that the sticking failure occurs in the electronic control coupling 48 by the sticking failure diagnosis unit 106, the first clutch Since it includes the clutch engagement control unit 104 which controls the clutch 24 and the second clutch 32 in the disconnected state, the first clutch is determined by the clutch engagement control unit 104 when it is diagnosed that the electronic control coupling 48 has a sticking failure. The 24 and the second clutch 32 are controlled to be in the disengaged state, respectively. Therefore, when a sticking failure occurs in the electronic control coupling 48, power transmission between the engine 12 and the power transmission path 52 and power transmission between the power transmission path 52 and the rear wheels 16L and 16R are respectively performed. Since it is cut, the circulation torque acting by the occurrence of the sticking failure in the electronic control coupling 48 is suitably suppressed.

  Further, according to the electronic control unit 100 of the four-wheel drive vehicle 10 of the present embodiment, the sticking failure diagnosis unit 106 transmits the power transmission between the engine 12 and the power transmission path 52 and the power transmission path 52 and the rear wheel 16L, Power transmission to and from 16R is connected by the first clutch 24 and the second clutch 32, respectively, and the first rotating element 48a on the front wheels 14L and 14R side and the second on the rear wheels 16L and 16R side of the electronic control coupling 48 In a state where the power transmission with the rotating element 48b is disconnected, the differential rotation (N1-N2) between the first rotating element 48a and the second rotating element 48b when the vehicle turns, that is, the coupling front-rear differential rotational speed Ns is actually If the sticking failure detection value Ns1 set in advance based on the steering angle θ1 of the steering wheel becomes equal to or less than the predetermined value, it is diagnosed that the sticking failure has occurred in the electronic control coupling . Thus, the sticking failure diagnosis unit 106 can appropriately diagnose whether the sticking failure has occurred in the electronic control coupling 48.

  Further, according to the four-wheel drive vehicle 10 of the present embodiment, the clutch engagement control unit 104 is diagnosed by the fixation failure diagnosis unit 106 that the fixation failure has occurred in the electronic control coupling 48, and the four-wheel drive vehicle 10 is When stopped, the first clutch 24 and the second clutch 32 are controlled to be in the disconnected state, for example, immediately after it is diagnosed by the sticking failure diagnosis unit 106 that the sticking failure has occurred in the electronic control coupling 48 while the vehicle is turning. The vehicle operability is improved as compared to controlling the one clutch 24 and the second clutch 32 in the disengaged state.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is also applicable in other aspects.

  For example, in the above-described first embodiment, when it is diagnosed that a sticking failure has occurred in the electronic control coupling 48 in S4, the first clutch 24 and the second clutch 32 are controlled to be in the disconnected state in S5. At S5, either one of the first clutch 24 and the second clutch 32 may be controlled to the disconnected state. Even if any one of the first clutch 24 and the second clutch 32 is controlled to be in the disengaged state in S5, the circulation torque acting by the occurrence of the sticking failure in the electronic control coupling 48 is suitably suppressed.

  Note that what has been described above is merely an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10: Four-wheel drive vehicle 12: Engine (drive power source)
14L, 14R: front wheels (main drive wheels)
16L, 16R: rear wheels (secondary drive wheels)
24: 1st clutch (1st disconnection device)
32: Second clutch (second disconnection device)
48: Electronic control coupling 52: Power transmission path 100: Electronic control device (control device)
104: Clutch engagement control unit (disconnection and connection device control unit)
106: sticking failure diagnosis unit (failure diagnosis unit)

Claims (1)

A pair of left and right main drive wheels to which the power of the drive power source is transmitted, and a pair of left and right main power wheels to which part of the power of the drive power source is transmitted via a power transmission path including electronic control coupling A second disconnecting device for connecting and disconnecting power transmission between the auxiliary driving wheel, the driving power source and the power transmission path, and second connecting and connecting power transmission between the power transmission path and the auxiliary driving wheel A control device of a four-wheel drive vehicle having a disconnection device, the control device comprising:
A failure diagnosis unit that diagnoses whether or not a sticking failure has occurred in the electronic control coupling;
A disconnection device control unit that controls at least one of the first disconnection device and the second disconnection device in a disconnection state when it is diagnosed by the failure diagnosis unit that a sticking failure occurs in the electronic control coupling And a control device for a four-wheel drive vehicle.

Images