Vehicular control device

Abstract

To provide a vehicular control device capable of fluently switching two-wheel drive and four-wheel drive, in a directly-coupled four-wheel drive vehicle.SOLUTION: A control part performs at least either one side of such a control as to decrease a torque of a first driving source and such a control as to increase a torque of a second driving source (step S6) in such a case that rotation number of a front wheel side clutch member is larger than rotation number of a rear wheel side clutch member when controlling a transfer so as to switch into an engagement state (NO at step S4). Further, the control part performs at least either one side of a control which increases the torque of the first driving source and a control which decreases the torque of the second driving source (step S5) in such a case that the rotation number of the front wheel side clutch member is smaller than the rotation number of rear wheel side clutch member (YES at the step S4).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] Patent Document 1 describes a part-time four-wheel drive hybrid vehicle in which the front wheels are driven by a motor generator built into a transfer case, and the rear wheels are driven by an engine via a transmission. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7052262 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the prior art described in Patent Document 1, if a motor-generator and an engine are connected by a transfer case with a dog clutch and the front and rear wheels are directly coupled without a differential device such as a center differential to improve off-road performance, such a direct-drive four-wheel drive vehicle may fail to engage or disengage the dog clutch while driving, preventing smooth switching between two-wheel drive and four-wheel drive. Specifically, when engaging the dog clutch to switch to four-wheel drive while driving, a differential rotation speed caused by a difference in the dynamic load radii of the tires may occur in the dog clutch, resulting in engagement failure. Furthermore, when disengaging the dog clutch to switch to two-wheel drive while driving, circulating torque may act on the dog clutch, resulting in friction between the tooth surfaces of the dog teeth, resulting in disengagement failure.

[0005] The present invention has been made in light of the above-mentioned circumstances, and aims to provide a vehicle control device that can smoothly switch between two-wheel drive and four-wheel drive in a direct-drive four-wheel drive vehicle. [Means for solving the problem]

[0006] The present invention relates to a control unit that is mounted on a vehicle including a first drive source capable of outputting torque to front wheels, a second drive source capable of outputting torque to rear wheels, and a transfer that has a front-wheel-side clutch member and a rear-wheel-side clutch member with dog teeth formed thereon, and that is switchable between an engaged state in which the front-wheel-side clutch member and the rear-wheel-side clutch member are engaged and a released state in which the front-wheel-side clutch member and the rear-wheel-side clutch member are released, and that transmits at least one of the torque output by the first drive source and the torque output by the second drive source to the front wheels and the rear wheels by switching to the engaged state. wherein, when controlling the transfer to be switched to the engaged state, if the rotation speed of the front wheel side clutch member is greater than the rotation speed of the rear wheel side clutch member, the control unit performs at least one of control to decrease the torque of the first driving source and control to increase the torque of the second driving source, and when controlling the transfer to be switched to the engaged state, if the rotation speed of the front wheel side clutch member is smaller than the rotation speed of the rear wheel side clutch member, the control unit performs at least one of control to increase the torque of the first driving source and control to decrease the torque of the second driving source. [Effects of the Invention]

[0007] As described above, according to the present invention, it is possible to provide a vehicle control device that can smoothly switch between two-wheel drive and four-wheel drive in a direct-drive four-wheel drive vehicle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart illustrating the clutch engagement operation performed by the vehicle control device according to one embodiment of the present invention. [Figure 3] FIG. 3 is a flowchart illustrating the clutch release operation performed by the vehicle control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] A vehicle control device according to one embodiment of the present invention is mounted on a vehicle including a first drive source capable of outputting torque to front wheels, a second drive source capable of outputting torque to rear wheels, and a transfer having a front-wheel-side clutch member and a rear-wheel-side clutch member with dog teeth formed thereon, the transfer being switched between an engaged state in which the front-wheel-side clutch member and the rear-wheel-side clutch member are engaged and a released state in which the front-wheel-side clutch member and the rear-wheel-side clutch member are released, and being switched to the engaged state to transmit at least one of the torque output by the first drive source and the torque output by the second drive source to the front wheels and the rear wheels, and the first drive source, the second drive source and the transfer a control unit for controlling a transfer case to switch to an engaged state, the control unit performing at least one of a control to decrease the torque of a first drive source or a control to increase the torque of a second drive source when the rotation speed of a front-wheel-side clutch member is higher than the rotation speed of a rear-wheel-side clutch member when controlling the transfer case to switch to an engaged state, and performing at least one of a control to increase the torque of the first drive source or a control to decrease the torque of the second drive source when the rotation speed of the front-wheel-side clutch member is lower than the rotation speed of the rear-wheel-side clutch member when controlling the transfer case to switch to an engaged state. As a result, the vehicle control device according to one embodiment of the present invention can smoothly switch between two-wheel drive and four-wheel drive in a direct-coupled four-wheel drive vehicle. [Example]

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle control device according to an embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figures 1 to 3 are diagrams illustrating a vehicle control device according to an embodiment of the present invention.

[0011] In Fig. 1, a vehicle 1 is equipped with a first drive source (referred to as MG in the figure) 20 capable of outputting torque to front wheels 28, and a second drive source (referred to as ICE in the figure) 2 capable of outputting torque to rear wheels 29. The first drive source 20 is a motor generator capable of power running and regeneration. The second drive source 2 is an internal combustion engine.

[0012] The vehicle 1 is equipped with a clutch 3 and a transmission 4. The clutch 3 is connected to an output shaft 2A of the second drive source 2. The transmission 4 has an input shaft 10 to which rotation is input from the second drive source 2 via the clutch 3, an output shaft 12 arranged coaxially with the input shaft 10, and a countershaft 11 arranged parallel to the input shaft 10 and the output shaft 12.

[0013] Transmission gears 10A, 10B, 10C, and 10D for first to fourth gears are arranged on the input shaft 10. The transmission gears 10A and 10B are fixed to the input shaft 10, and the transmission gears 10C and 10D are provided on the input shaft 10 so as to be able to rotate freely.

[0014] A reverse gear 10R for reverse travel and an output gear 16 are fixed to the output shaft 12. The output shaft 12 is connected to left and right rear wheels 29 via a rear differential device 5.

[0015] Speed ​​change gears 11A, 11B, 11C, and 11D for first to fourth gears and a reverse gear 11R for reverse travel are arranged on countershaft 11. Speed ​​change gears 11A and 11B are rotatably mounted on countershaft 11, while speed change gears 11C, 11D and reverse gear 11R are fixed to countershaft 11. Speed ​​change gears 10A, 10B, 10C, and 10D and reverse gear 10R on input shaft 10 are constantly in mesh with speed change gears 11A, 11B, 11C, and 11D and reverse gear 11R on countershaft 11.

[0016] The transmission 4 is equipped with switching mechanisms 13, 14, and 15 that switch between gear positions. The switching mechanism 13 is provided on the counter shaft 11 between the transmission gear 11A and the transmission gear 11B. The switching mechanism 14 is provided on the input shaft 10 between the transmission gear 10C and the transmission gear 10D.

[0017] The switching mechanism 15 is provided between the input shaft 10 and the output shaft 12, and transmits the rotation of the input shaft 10 to the output shaft 12 as is by engaging with an output gear 10E provided on the output shaft 12.

[0018] The vehicle 1 has a gear 17 that meshes with the output gear 16 and a gear 18 that rotates integrally with the gear 17.

[0019] The vehicle 1 has a reduction gear 22 that rotates integrally with the output shaft 21 of the first drive source 20, and a reduction gear 23 that meshes with the reduction gear 22. The vehicle 1 has a reduction gear 24 that rotates integrally with the reduction gear 23, and a reduction gear 25 that meshes with the reduction gear 24.

[0020] The vehicle 1 is provided with a rotary shaft 26 that rotates integrally with the reduction gear 25. The rotary shaft 26 is connected to left and right front wheels 28 via a front differential device 7.

[0021] The vehicle 1 is equipped with a transfer 27. The transfer 27 has a front-wheel-side clutch member CB and a rear-wheel-side clutch member CA, each having dog teeth formed thereon. The front-wheel-side clutch member CB and the rear-wheel-side clutch member CA form a dog clutch C that can be engaged with each other via their dog teeth. The rear-wheel-side clutch member CA rotates integrally with a gear 19, which is in mesh with a gear 18. The front-wheel-side clutch member CB rotates integrally with an output shaft 21 of a first drive source 20. When the dog clutch C is engaged, the transfer 27 can transmit power from the first drive source 20 or the second drive source 2 to both the front wheels 28 and the rear wheels 29.

[0022] The transfer 27 is switched between an engaged state in which the front wheel side clutch member CB and the rear wheel side clutch member CA are engaged, and a disengaged state in which the front wheel side clutch member CB and the rear wheel side clutch member CA are disengaged.

[0023] When switched to an engaged state, the transfer 27 transmits at least one of the torque output by the first drive source 20 (hereinafter also referred to as motor torque) and the torque output by the second drive source 2 (hereinafter also referred to as engine torque) to the front wheels 28 and the rear wheels 29. Therefore, when the transfer 27 is switched to an engaged state, the vehicle 1 can travel in a four-wheel drive state in which the front wheels 28 and the rear wheels 29 are driven by the resultant force of the torque output by the first drive source 20 and the torque output by the second drive source 2, a four-wheel drive state in which the front wheels 28 and the rear wheels 29 are driven by the torque output by the first drive source 20, or a four-wheel drive state in which the front wheels 28 and the rear wheels 29 are driven by the torque output by the second drive source 2. In this way, the vehicle 1 is a part-time direct-coupled four-wheel drive vehicle configured to be connectable between the first drive source 20 and the second drive source 2 by the transfer 27 having a dog clutch C without via a differential device such as a center differential.

[0024] The vehicle 1 includes an ECU 30 as a vehicle control device. The ECU 30 includes a control unit 30A that controls the first drive source 20, the second drive source 2, and the transfer 27.

[0025] The vehicle 1 is configured as a direct drive four-wheel drive vehicle that does not have a differential device such as a center differential, and therefore, as will be explained below, has the problem that engagement cannot be performed smoothly due to a difference in rotation speed in the dog clutch C, and the problem that release cannot be performed smoothly due to a circulating torque acting on the dog clutch C. Furthermore, the following measures have been taken to address these problems.

[0026] In other words, the rotation speeds of the rear wheel clutch member CA and front wheel clutch member CB of the dog clutch C of the transfer 27 change depending on the dynamic load radius of the tires and the degree of turning. If the center of gravity of the vehicle is biased to either the front or rear, the load is applied to the tire on that side, reducing the dynamic load radius and increasing the rotation speed, which causes a difference in rotation speed.

[0027] When the vehicle 1 is turning, the travel path of the rear wheels 29 is on the inside of the turn compared to the travel path of the front wheels 28 due to a so-called inside wheel difference, so the travel distance of the front wheels 28 is longer than the travel distance of the rear wheels 29, and the rotation speed of the front wheels 28 is higher. This can increase the difference in rotation speed between the rear wheel side clutch member CA and the front wheel side clutch member CB. If the difference in rotation speed becomes too large, the dog clutch C cannot be engaged.

[0028] Therefore, when engaging the dog clutch C, the control unit 30A controls the motor torque and the engine torque so that the difference in rotation speed between the rear wheel side clutch member CA and the front wheel side clutch member CB becomes small.

[0029] For example, when the rotation speed of the front wheels 28 is faster than that of the rear wheels 29, the motor torque is reduced to reduce the rotation speed of the front wheels 28. As one mode of control to reduce the motor torque, the control unit 30A performs control to regenerate the first drive source 20 and make the motor torque a regenerative torque (hereinafter also simply referred to as regeneration).

[0030] On the other hand, when the rotation speed of the rear wheels 29 is faster than that of the front wheels 28, the control unit 30A increases the motor torque to increase the rotation speed of the front wheels 28. As one mode of control to increase the motor torque, the control unit 30A powers the first drive source 20 and controls the motor torque to be powering torque (hereinafter also simply referred to as powering).

[0031] In order to suppress torque fluctuations of the vehicle 1, the control unit 30A may increase the engine torque when decreasing the motor torque, or may decrease the engine torque when increasing the motor torque, thereby enabling the difference in rotation speed to be quickly reduced.

[0032] Furthermore, by simultaneously changing both the motor torque and the engine torque in this way, the total torque fluctuation of the vehicle 1 becomes zero, and deterioration of drivability can be prevented.

[0033] The difference in rotation speed between the rear wheel side clutch member CA and the front wheel side clutch member CB can be calculated by installing a rotation speed sensor (not shown) on the rear wheel side clutch member CA and the front wheel side clutch member CB, or by obtaining the rotation speed of each wheel using a wheel speed sensor (not shown).

[0034] In addition, in a four-wheel drive state in which the dog clutch C of the transfer 27 is engaged, a circulating torque is generated because there is no differential device such as a center differential between the front wheels 28 and the rear wheels 29, and this circulating torque acts on the dog clutch C.

[0035] Therefore, when the dog clutch C is controlled to be released, the dog tooth surfaces of the rear wheel side clutch member CA and the front wheel side clutch member CB are pressed against each other due to the circulating torque, and the friction between the dog tooth surfaces may prevent the dog clutch C from being released smoothly.

[0036] The circulating torque can be reduced by decreasing the rotation speed of one of the rear wheel clutch member CA and the front wheel clutch member CB, which rotates faster, and increasing the rotation speed of the other.

[0037] However, when the dog clutch C is engaged, the rear wheel clutch member CA and the front wheel clutch member CB rotate together, and no difference in rotation speed occurs, so it is difficult to determine how the circulating torque is acting based on the difference in rotation speed.

[0038] For example, when the vehicle 1 is turning with the center of gravity at the rear, the dynamic load radius of the rear wheel 29 tends to be small because the center of gravity is at the rear, and the rotation speed of the rear wheel clutch member CA tends to be large; however, if the dog clutch C cannot be released in this state, it is difficult to determine how the circulating torque is acting.

[0039] Therefore, the control unit 30A increases or decreases the torque of one or both of the rear wheel side clutch member CA and the front wheel side clutch member CB, which are in an engaged state, in order to reduce the pressure acting on the dog teeth between the rear wheel side clutch member CA and the front wheel side clutch member CB and enable the dog clutch C to be smoothly switched to a released state, and continues this operation until the release is successful.

[0040] The control unit 30A controls, for example, by changing the motor torque acting on the front wheel side clutch member CB between powering and regenerating, or by changing the engine torque acting on the rear wheel side clutch member CA between increasing and decreasing, so that one of the circulating torques is released to engage the dog clutch C, and then the other circulating torque is released to release the dog clutch C.

[0041] In addition, the control unit 30A may, for example, reduce the engine torque acting on the rear wheel side clutch member CA while powering the motor torque acting on the front wheel side clutch member CB, and then conversely increase the engine torque acting on the rear wheel side clutch member CA while regenerating the motor torque acting on the front wheel side clutch member CB, or may increase the engine torque acting on the rear wheel side clutch member CA while regenerating the motor torque acting on the front wheel side clutch member CB, and then conversely reduce the engine torque acting on the rear wheel side clutch member CA while powering the motor torque acting on the front wheel side clutch member CB.

[0042] In this way, the change in motor torque and the change in engine torque can be offset, the fluctuation in the total torque of the vehicle 1 can be made zero, and deterioration of drivability can be prevented.

[0043] If it is possible to predict that a load is applied to the front wheels 28 or that the vehicle 1 is turning, it is preferable to initially increase the engine torque while regenerating the motor torque. If it is possible to predict that the vehicle 1 is traveling straight and that a load is applied to the rear wheels 29, it is preferable to initially reduce the engine torque while powering the motor torque.

[0044] When controlling the transfer case 27 to be switched to the engaged state, if the rotation speed of the front-wheel-side clutch member CB is greater than the rotation speed of the rear-wheel-side clutch member CA, the control unit 30A performs at least one of a control to decrease the torque of the first driving source 20 and a control to increase the torque of the second driving source 2. In other words, the control unit 30A may perform only one of a control to decrease the torque of the first driving source 20 and a control to increase the torque of the second driving source 2, a control to decrease the torque of the first driving source 20 and a control to increase the torque of the second driving source 2 first and then the other, or a control to decrease the torque of the first driving source 20 and a control to increase the torque of the second driving source 2 simultaneously.

[0045] In addition, when the control unit 30A controls the transfer 27 to switch to an engaged state, if the rotation speed of the front wheel side clutch member CB is smaller than the rotation speed of the rear wheel side clutch member CA, the control unit 30A performs at least one of control to increase the torque of the first driving source 20 and control to decrease the torque of the second driving source 2.

[0046] When the control unit 30A controls the transfer 27 to switch to an engaged state, if the rotation speed of the front wheel side clutch member CB is greater than the rotation speed of the rear wheel side clutch member CA, it is preferable that the control unit 30A performs both control to reduce the torque of the first driving source 20 and control to increase the torque of the second driving source 2.

[0047] In addition, when the control unit 30A controls the transfer 27 to switch to an engaged state, if the rotation speed of the front wheel side clutch member CB is smaller than the rotation speed of the rear wheel side clutch member CA, it is preferable that the control unit 30A perform both control to increase the torque of the first driving source 20 and control to decrease the torque of the second driving source 2.

[0048] If the transfer 27 does not switch to the open state when the control unit 30A controls the transfer 27 to switch to the open state, the control unit 30A performs at least one of the following: a control to decrease or increase the torque of the first driving source 20 and then increase or decrease the torque of the first driving source 20; and a control to increase or decrease the torque of the second driving source 2 and then decrease or increase the torque of the second driving source 2.

[0049] If the transfer 27 does not switch to the open state when the control unit 30A controls it to switch to the open state, it is preferable that the control unit 30A perform at least one of the following controls: a control to decrease the torque of the first driving source 20 while increasing the torque of the second driving source 2, and then a control to increase the torque of the first driving source 20 while decreasing the torque of the second driving source 2, and then a control to increase the torque of the first driving source 20 while decreasing the torque of the second driving source 2, and then a control to increase the torque of the second driving source 2 while decreasing the torque of the first driving source 20.

[0050] The engagement operation of the transfer case 27 performed by the control unit 30A of the ECU 30 will be described with reference to the flowchart shown in FIG.

[0051] The control unit 30A determines whether or not to engage the dog clutch C (step S1). If it is determined that the dog clutch C is not to be engaged (NO in step S1), the control unit 30A executes step S1 again.

[0052] When the control unit 30A determines that the dog clutch C is to be engaged (YES in step S1), it acquires the rotation speeds of the rear wheel side clutch member CA (denoted as CA in the figure) and the front wheel side clutch member CB (denoted as CB in the figure) (step S2).

[0053] Next, the control unit 30A determines whether the absolute value of the differential rotation speed obtained by subtracting the rotation speed of the front wheel side clutch member CB (referred to as CB rotation speed in the figure) from the rotation speed of the rear wheel side clutch member CA (referred to as CA rotation speed in the figure) is greater than or equal to a predetermined value (step S3).

[0054] If the absolute value of the differential rotation speed is equal to or greater than the predetermined value (YES in step S3), the control unit 30A determines whether the rotation speed of the rear wheel side clutch member CA is greater than the rotation speed of the front wheel side clutch member CB (step S4).

[0055] If the rotation speed of the rear wheel side clutch member CA is greater than the rotation speed of the front wheel side clutch member CB (YES in step S4), the control unit 30A performs at least one of control to increase the motor torque (referred to as powering in the figure) and control to decrease the engine torque (step S5), and returns to step S2.

[0056] If the rotation speed of the rear wheel side clutch member CA is not greater than the rotation speed of the front wheel side clutch member CB (NO in step S4), the control unit 30A performs at least one of control to reduce the motor torque (referred to as regeneration in the figure) and control to increase the engine torque (step S6), and returns to step S2.

[0057] If the absolute value of the differential rotation speed is less than the predetermined value (NO in step S3), the control unit 30A engages the dog clutch C (step S7).

[0058] Next, the control unit 30A determines whether or not the engagement of the dog clutch C has been successful (step S8).

[0059] If the control unit 30A determines that the engagement has not been successful (NO in step S8), it returns to step S2, and if it determines that the engagement has been successful (YES in step S8), it ends the current operation.

[0060] The opening operation of the transfer case 27 by the control unit 30A of the ECU 30 will be described with reference to the flowchart shown in FIG.

[0061] The control unit 30A determines whether or not to release the dog clutch C (step S11). If it is determined that the dog clutch C should not be released (NO in step S11), the control unit 30A executes step S11 again.

[0062] When the control unit 30A determines that the dog clutch C is to be released (YES in step S11), the control unit 30A releases the dog clutch C (step S12).

[0063] Next, the control unit 30A determines whether or not the dog clutch C has been successfully released (step S13). If the control unit 30A determines that the dog clutch C has been successfully released (YES in step S13), it ends the current operation.

[0064] If the control unit 30A determines that the dog clutch C has not been successfully released (NO in step S13), it performs at least one of control to increase the motor torque (referred to as powering in the figure) and control to decrease the engine torque (step S14).

[0065] Next, the control unit 30A determines whether or not the dog clutch C has been successfully released (step S15). If the control unit 30A determines that the dog clutch C has been successfully released (YES in step S15), it ends the current operation.

[0066] If the control unit 30A determines that the dog clutch C has not been released successfully (NO in step S15), it performs at least one of control to reduce the motor torque (referred to as regeneration in the figure) and control to increase the engine torque (step S16), and then ends the current operation.

[0067] The order of steps S14 and S16 may be reversed. That is, if it is determined in step S13 that the dog clutch C has not been released successfully, first, at least one of control to decrease the motor torque and control to increase the engine torque may be performed, and thereafter, if it is determined in step S15 that the dog clutch C has not been released successfully, at least one of control to increase the motor torque and control to decrease the engine torque may be performed.

[0068] As described above, in the embodiment, when controlling the transfer case 27 to be switched to the engaged state, if the rotation speed of the front-wheel-side clutch member CB is higher than the rotation speed of the rear-wheel-side clutch member CA, the control unit 30A performs at least one of control to decrease the torque of the first driving source 20 and control to increase the torque of the second driving source 2. Furthermore, when controlling the transfer case 27 to be switched to the engaged state, if the rotation speed of the front-wheel-side clutch member CB is lower than the rotation speed of the rear-wheel-side clutch member CA, the control unit 30A performs at least one of control to increase the torque of the first driving source 20 and control to decrease the torque of the second driving source 2.

[0069] As a result, if the rotation speed of the front-wheel-side clutch member CB is higher than the rotation speed of the rear-wheel-side clutch member CA when controlling the transfer case 27 to switch to the engaged state, the rotation speed of the front-wheel-side clutch member CB decreases due to a decrease in torque of the first drive source 20, or the rotation speed of the rear-wheel-side clutch member CA increases due to an increase in torque of the second drive source 2, making it possible to make the rotation speed of the front-wheel-side clutch member CB and the rotation speed of the rear-wheel-side clutch member CA equal. This allows the dog teeth of the front-wheel-side clutch member CB to mesh with the dog teeth of the rear-wheel-side clutch member CA, allowing the transfer case 27 to be smoothly switched to the engaged state. As a result, a direct-coupled four-wheel drive vehicle can smoothly switch between two-wheel drive and four-wheel drive.

[0070] In the embodiment, when controlling the transfer case 27 to be switched to the engaged state, if the rotation speed of the front-wheel-side clutch member CB is higher than the rotation speed of the rear-wheel-side clutch member CA, the control unit 30A performs both a control to decrease the torque of the first driving source 20 and a control to increase the torque of the second driving source 2. When controlling the transfer case 27 to be switched to the engaged state, if the rotation speed of the front-wheel-side clutch member CB is lower than the rotation speed of the rear-wheel-side clutch member CA, the control unit 30A performs both a control to increase the torque of the first driving source 20 and a control to decrease the torque of the second driving source 2.

[0071] As a result, if the rotation speed of the front-wheel-side clutch member CB is higher than the rotation speed of the rear-wheel-side clutch member CA when the transfer case 27 is switched to the engaged state, the rotation speed of the front-wheel-side clutch member CB decreases due to a decrease in torque of the first drive source 20, and the rotation speed of the rear-wheel-side clutch member CA increases due to an increase in torque of the second drive source 2, making it possible to make the rotation speed of the front-wheel-side clutch member CB and the rotation speed of the rear-wheel-side clutch member CA equal. This allows the dog teeth of the front-wheel-side clutch member CB and the dog teeth of the rear-wheel-side clutch member CA to mesh with each other, allowing the transfer case 27 to be smoothly switched to the engaged state.

[0072] As a result, in a direct-drive four-wheel drive vehicle, switching between two-wheel drive and four-wheel drive can be performed smoothly. In addition, the torque variations between the first drive source 20 and the second drive source 2 are canceled out, and vehicle torque is kept constant, preventing deterioration of drivability.

[0073] In addition, in the embodiment, if the transfer 27 does not switch to the open state when the control unit 30A controls the transfer 27 to switch to the open state, the control unit 30A performs at least one of the following: a control to decrease or increase the torque of the first driving source 20 and then increase or decrease the torque of the first driving source 20; and a control to increase or decrease the torque of the second driving source 2 and then decrease or increase the torque of the second driving source 2.

[0074] As a result, when the transfer 27 does not switch to the disengaged state when controlled to do so, the torque of the first drive source 20 or the second drive source 2 increases or decreases, thereby reducing the circulating torque acting on the transfer 27 and reducing the pressure acting on the dog teeth of the front wheel side clutch member CB and the rear wheel side clutch member CA, so that the transfer 27 can be switched to the disengaged state. As a result, in a direct-coupled four-wheel drive vehicle, switching between two-wheel drive and four-wheel drive can be performed smoothly.

[0075] In addition, in the embodiment, if the transfer 27 does not switch to the open state when the control unit 30A controls the transfer 27 to switch to the open state, the control unit 30A performs at least one of the following controls: a control to increase the torque of the second drive source 2 while decreasing the torque of the first drive source 20, and then a control to decrease the torque of the second drive source 2 while increasing the torque of the first drive source 20; and a control to increase the torque of the second drive source 2 while increasing the torque of the first drive source 20, and then a control to increase the torque of the second drive source 2 while decreasing the torque of the first drive source 20.

[0076] As a result, when the transfer case 27 does not switch to the disengaged state when controlled to do so, the torque of the first drive source 20 or the second drive source 2 increases or decreases, thereby reducing the circulating torque acting on the transfer case 27 and reducing the pressure acting on the dog teeth of the front-wheel clutch member CB and the rear-wheel clutch member CA, allowing the transfer case 27 to switch to the disengaged state. As a result, in a direct-coupled four-wheel drive vehicle, switching between two-wheel drive and four-wheel drive can be performed smoothly. In addition, the torque changes between the first drive source 20 and the second drive source 2 are offset, keeping the vehicle torque constant, preventing a deterioration in drivability.

[0077] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0078] 1 vehicle 2 Second drive source 20 First driving source 27 Transfer 28 front wheel 29 rear wheel 30A control unit CA rear wheel clutch member CB front wheel clutch member

Claims

1. a first drive source capable of outputting torque to the front wheels; a second drive source capable of outputting torque to the rear wheels; a transfer having a front wheel side clutch member and a rear wheel side clutch member with dog teeth formed thereon, which is switchable between an engaged state in which the front wheel side clutch member and the rear wheel side clutch member are engaged with each other and a released state in which the front wheel side clutch member and the rear wheel side clutch member are released, and which transmits at least one of the torque output by the first drive source and the torque output by the second drive source to the front wheels and the rear wheels by switching to the engaged state; A vehicle control device including a control unit that controls the first drive source, the second drive source, and the transfer case, The control unit when controlling the transfer to switch to the engaged state, if the rotation speed of the front wheel side clutch member is greater than the rotation speed of the rear wheel side clutch member, performing at least one of a control to decrease the torque of the first drive source and a control to increase the torque of the second drive source; A vehicle control device characterized in that, when controlling the transfer to switch to the engaged state, if the rotation speed of the front wheel side clutch member is smaller than the rotation speed of the rear wheel side clutch member, at least one of control to increase the torque of the first drive source and control to decrease the torque of the second drive source is performed.

2. The control unit when controlling the transfer to switch to the engaged state, if the rotation speed of the front wheel side clutch member is greater than the rotation speed of the rear wheel side clutch member, performing both a control to decrease the torque of the first drive source and a control to increase the torque of the second drive source; 2. A vehicle control device as described in claim 1, characterized in that when controlling the transfer to switch to the engaged state, if the rotation speed of the front wheel side clutch member is smaller than the rotation speed of the rear wheel side clutch member, both control to increase the torque of the first drive source and control to decrease the torque of the second drive source are performed.

3. a first drive source capable of outputting torque to the front wheels; a second drive source capable of outputting torque to the rear wheels; a transfer having a front wheel side clutch member and a rear wheel side clutch member with dog teeth formed thereon, which is switchable between an engaged state in which the front wheel side clutch member and the rear wheel side clutch member are engaged with each other and a released state in which the front wheel side clutch member and the rear wheel side clutch member are released, and which transmits at least one of the torque output by the first drive source and the torque output by the second drive source to the front wheels and the rear wheels by switching to the engaged state; A vehicle control device including a control unit that controls the first drive source, the second drive source, and the transfer case, The control unit If the transfer does not switch to the open state when controlled to switch to the open state, control of increasing or decreasing the torque of the first drive source after decreasing or increasing the torque of the first drive source; and (b) increasing or decreasing the torque of the second drive source and then increasing or decreasing the torque of the second drive source.

4. The control unit If the transfer does not switch to the open state when controlled to switch to the open state, a control of increasing the torque of the second driving source while decreasing the torque of the first driving source, and then decreasing the torque of the second driving source while increasing the torque of the first driving source; 4. The vehicle control device according to claim 3, further comprising: a control for increasing the torque of the first drive source while decreasing the torque of the second drive source, and then a control for increasing the torque of the second drive source while decreasing the torque of the first drive source.

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