JP2016159745A - Control device of four-wheel drive car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device of a four-wheel drive car capable of suppressing deterioration in fuel consumption performance due to a prolonged state in which a distribution torque distributed to auxiliary driving wheels is increased to suppress occurrence of abnormal noise.SOLUTION: A control device of a four-wheel drive car 10 comprises: abnormal-noise-suppression means 34 for increasing a distribution torque distributed to auxiliary driving wheels 12R to suppress abnormal noise when an operation area of an engine 14 is in an abnormal noise occurrence area; and transition-suppression means 34 for suppressing, when the operation area of the engine 14 is in the abnormal noise occurrence area, a transition to a predetermined operation control for continuing the state in which the operation area of the engine 14 is in the abnormal noise occurrence area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a four-wheel drive vehicle that distributes engine output torque to main drive wheels and auxiliary drive wheels.

  As a four-wheel drive vehicle, a rear wheel drive transfer is provided in a power unit that is composed of an engine, a transmission, and a front wheel differential and is mounted on the front part of the vehicle body and drives the left and right front wheels as main drive wheels. In addition, a propeller shaft extending in the longitudinal direction of the vehicle body is connected to the transfer, and a rear wheel differential is connected to the rear end of the transfer so that left and right rear wheels as auxiliary drive wheels can be driven. It has been.

  In the four-wheel drive vehicle, a coupling capable of varying the transmission torque may be disposed on the propeller shaft, and the output torque of the engine is evenly transmitted to the front and rear wheels by completely fastening the coupling. The four-wheel drive state is established, and the coupling output is completely released, so that the engine output torque is transmitted only to the front wheels, and the coupling is between the complete fastening and full release of the coupling. The distribution of torque transmitted to the rear wheels is adjusted according to the state.

  The transfer has a pair of bevel gears that mesh with each other, specifically, a front wheel differential, in order to transmit power from a front wheel differential device having an axial center extending in the vehicle width direction to a propeller shaft extending in the vehicle body longitudinal direction. A bevel gear provided on the axis of the apparatus and a bevel gear provided on the axis of the propeller shaft are generally used.

  In the four-wheel drive vehicle, the drive loss increases in the four-wheel drive state in which the front wheels and the rear wheels are driven as the engine output torque is distributed to the rear wheels, compared to the two-wheel drive state in which only the front wheels are driven. Since the fuel efficiency deteriorates, the vehicle is usually driven in a two-wheel drive state, and the four-wheel drive state is set only when necessary.

  However, the engine output torque fluctuates due to intermittent explosions in the combustion chamber of the engine, and this torque fluctuation is transmitted to the transfer via the transmission and the differential for the front wheels. A drive system including a propeller shaft extending from the bevel gear to the rear wheel, a rear wheel differential, and the like rotates in a non-power transmission state in which power is not transmitted.

  Therefore, depending on the frequency of torque fluctuation of the engine, the drive system having a predetermined natural frequency with respect to torsional vibration resonates with the torque fluctuation of the engine, and the vibration of the drive system increases. An abnormal noise due to gearing or the like between the pair of bevel gears may occur, causing noise in the passenger compartment.

FIG. 5 is a diagram showing the relationship between the torque fluctuation frequency of the engines of the four-wheel drive vehicle and the two-wheel drive vehicle to which the basic structure corresponds and the transmission characteristics with respect to the torsional vibration of the drive system. Both the waveform of the transmission characteristic for the torsional vibration of the four-wheel drive vehicle shown in FIG. 5 (the waveform indicated by the solid line) W1 and the waveform of the transmission characteristic for the torsional vibration of the two-wheel drive vehicle (the waveform indicated by the broken line) W2 outside it has the peak P1, P2 of the resonance at the frequency (less than frequency f _L), the frequency of practical range of the engine (or frequency f _L), the waveform W1 of the four-wheel drive vehicle, the two-wheel drive vehicle The waveform W2 has a resonance peak P3 that is not found, and abnormal noise may be generated due to vibration caused by the peak P3.

  With respect to the resonance peak P3 of the drive system unique to this four-wheel drive vehicle, a load is applied to the drive system from a two-wheel drive state in which only the front wheels are driven in an operation region where the drive system resonates with engine torque fluctuations. Giving and transmitting a predetermined torque to the rear wheels by increasing the torque distribution to the rear wheels by the coupling, and generating abnormal noise due to gearing between the pair of bevel gears due to resonance of the drive system It is conceivable to suppress this.

  In a four-wheel drive vehicle, it suppresses gear rattling caused by a drive system consisting of a propeller shaft extending from a bevel gear to a rear wheel in a transfer and a differential for a rear wheel, etc., which resonates due to engine torque fluctuations. However, in Patent Document 1, for example, in the engine knocking generation region, in order to suppress the occurrence of noise due to vibration caused by knocking transmitted from the transfer to the rear wheel differential, Increasing the distribution of engine output torque is disclosed.

JP 2001-277881 A

  In recent years, according to the driver's operation, cruise control for controlling the vehicle speed or the inter-vehicle distance to be maintained at a set target value, upper limit vehicle speed control for controlling the vehicle speed so as not to exceed the set upper limit vehicle speed, etc. A vehicle to perform is known, and in such a vehicle, cruise control, upper limit vehicle speed control, and the like are performed by automatically controlling engine output, brakes, and the like.

  In a four-wheel drive vehicle that performs cruise control, upper limit vehicle speed control, etc., the drive system consisting of the propeller shaft from the bevel gear to the rear wheel in the transfer and the differential device for the rear wheel resonates with engine torque fluctuations and generates abnormal noise. Increase the distribution torque to the rear wheel when cruise control or upper limit vehicle speed control is performed while increasing the distribution torque to the rear wheel and suppressing the generation of abnormal noise in the abnormal noise generation operation area There is a high possibility that the maintained state will be continued for a long time, which may increase the deterioration of fuel consumption.

  In addition, in a high compression ratio engine with a high compression ratio to improve fuel efficiency and a premixed compression self ignition (HCCI) engine in which a mixed gas of air and fuel is compressed and ignited, the fluctuation torque of the engine Since the torque increases, the torque distributed to the rear wheels, which is increased in order to suppress the generation of abnormal noise, also increases, so the problem can be more prominent.

  Therefore, the present invention suppresses the generation of abnormal noise by increasing the distribution torque to the auxiliary drive wheels in a four-wheel drive vehicle in which the engine output torque is distributed to the main drive wheels and the auxiliary drive wheels. It aims at suppressing the deterioration of the fuel consumption by the state which exists being continued over a long time.

  In order to solve the above problems, the present invention is configured as follows.

  First, the invention according to claim 1 of the present application is provided with an engine, torque transmission means for transmitting the output torque of the engine to the main drive wheel and the auxiliary drive wheel, and the torque transmission means. Torque distribution adjusting means for adjusting torque to be distributed to the auxiliary drive wheels out of torque, and when the engine operating region is in an abnormal sound generation region where abnormal noise is generated by the torque transmitting unit. A control device for a four-wheel drive vehicle, wherein the torque distribution adjusting means increases the torque distribution to the auxiliary drive wheels so as to suppress the occurrence of noise, and the engine operating region is the abnormal noise. And a transition restraining means for restraining transition to a predetermined operation control for continuing that the engine operating region is in the abnormal noise generating region when in the generating region. To.

  According to a second aspect of the present invention, in the control device for a four-wheel drive vehicle according to the first aspect, the transition suppressing means continues that the operating region of the engine is in the abnormal noise generation region. The shift to the predetermined operation control is prohibited.

  The invention according to claim 3 is the control device for a four-wheel drive vehicle according to claim 1 or 2, wherein the transition suppressing means has the engine operating region in the abnormal noise generating region. It is characterized by notifying the driver that the vehicle is in a state of prohibiting the transition to the predetermined operation control that continues this.

  According to a fourth aspect of the present invention, in the control device for a four-wheel drive vehicle according to any one of the first to third aspects, the predetermined operation control is performed by setting a vehicle speed or an inter-vehicle distance. Cruise control for controlling to maintain the target value, upper limit vehicle speed control for controlling the vehicle speed so as not to exceed the set upper limit vehicle speed, and manual shift mode control for shifting control of the automatic transmission based on the manual operation of the occupant, Is at least one control.

  With the above configuration, according to the first aspect of the present invention, when the engine operating region is in the abnormal noise generation region, the predetermined operation for continuing that the engine operating region is in the abnormal noise generation region. Since the shift to control is suppressed, it is possible to prevent the torque distribution to the auxiliary drive wheels from continuing to increase so as to suppress the generation of abnormal noise, and increase the distribution torque to the auxiliary drive wheels. Thus, it is possible to suppress the deterioration of fuel consumption due to the state where the generation of abnormal noise is suppressed for a long time.

  Further, according to the invention described in claim 2, the engine operating area is abnormally generated by prohibiting the transition to the predetermined operation control that continues the engine operating area being in the abnormal noise generating area. Transition to operation control that continues to be in the region can be prohibited, and the above effect can be obtained effectively.

  According to the third aspect of the present invention, the driver is notified that the engine operation region is in a state in which the shift to the predetermined operation control that continues the existence of the noise operation region is prohibited. As a result, it is possible to prevent the driver from performing an operation of shifting to the operation control that continues the engine operation region being in the abnormal noise generation region, and the effect can be obtained effectively.

  According to the fourth aspect of the present invention, the predetermined operation control for continuing that the engine operation region is in the abnormal noise generation region is at least one of cruise control, upper limit vehicle speed control, and manual shift mode control. The effect can be specifically realized by one control.

1 is a schematic configuration diagram of a four-wheel drive vehicle according to a first embodiment of the present invention. It is a graph which shows the relationship between the engine speed in the said four-wheel drive vehicle, the fluctuation torque of a drive system, and the distribution torque to a rear wheel. It is a flowchart which shows control of the said four-wheel drive vehicle. It is a flowchart which shows control of the four-wheel drive vehicle which concerns on 2nd Embodiment of this invention. It is a figure which shows the relationship between the transmission characteristic with respect to the torsional vibration of a drive system, and the frequency of the torque fluctuation of the engine of the four-wheel drive vehicle with which basic structure respond | corresponds.

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

  FIG. 1 is a schematic configuration diagram of a four-wheel drive vehicle according to a first embodiment of the present invention. As shown in FIG. 1, a four-wheel drive vehicle 10 according to a first embodiment of the present invention includes an engine 14 as a drive source, and a transmission for transmitting output torque of the engine 14 to front wheels 12F and rear wheels 12R. (Transmission) 16 and a transmission case 17 having a front wheel differential 20 that transmits the driving force from the transmission 16 to the left and right front wheels 12F via the axle 18 and the driving force transmitted to the rear wheels 12R are taken out. A transfer 22 and a rear-wheel differential device 26 that transmits the driving force from the transfer 22 to the left and right rear wheels 12R via an axle 24 are provided.

  As the transmission 16, for example, an automatic transmission having a torque converter is used. The transmission 16 has a predetermined gear position according to the driving state of the four-wheel drive vehicle 10, specifically according to the vehicle speed and the accelerator opening. Configured to achieve.

  The transfer 22 and the rear wheel differential device 26 are connected to each other via a propeller shaft 30 and a coupling 28 that extend in the longitudinal direction of the vehicle body. The output shaft of the transfer 22 is connected to one end of the propeller shaft 30, the other end of the propeller shaft 30 is connected to the input shaft of the coupling 28, and the output shaft of the coupling 28 is the input shaft of the rear wheel differential device 26. It is connected to.

  The transfer 22 has a pair of bevel gears (not shown) that mesh with each other in order to transmit power from the front wheel differential device 20 whose axial center extends in the vehicle width direction to the propeller shaft 30 that extends in the vehicle body longitudinal direction. A bevel gear provided on the axis of the front wheel differential 20 and a bevel gear provided on the axis of the propeller shaft 30 are used.

  The coupling 28 uses an electromagnetic coupling or the like, and is configured to adjust the torque distributed to the rear wheels 12 </ b> R out of the output torque of the engine 14. In the four-wheel drive vehicle 10, the torque distribution between the front wheels 12 </ b> F and the rear wheels 12 </ b> R can be varied by the coupling 28 from front wheels: rear wheels = 100: 0 to 50:50.

  In the present embodiment, the front wheel 12F is the main drive wheel, the rear wheel 12R is the auxiliary drive wheel, the transmission 16, the front wheel differential 20, the axle 18, the transfer 22, the propeller shaft 30, the coupling 28, and the rear wheel. The differential gear 26 and the axle 24 constitute torque transmission means for transmitting the output torque of the engine 14 to the front wheels 12F and the rear wheels 12R, and the coupling 28 distributes the output torque of the engine 14 to the rear wheels 12R. Torque distribution adjusting means for adjusting the torque to be performed is configured.

  The four-wheel drive vehicle 10 includes an accelerator opening sensor 36 that detects an accelerator pedal depression amount (accelerator opening) by a driver, an engine rotation speed sensor 38 that detects the rotation speed of the engine 14, and a vehicle speed. A vehicle speed sensor 40, a cruise control switch 42 for starting cruise control for controlling the vehicle speed or the inter-vehicle distance to be maintained at a set target value, and an upper limit for controlling the vehicle speed so as not to exceed the set upper vehicle speed An upper limit vehicle speed control switch 44 for starting the vehicle speed control and a control unit 34 for controlling the operation of the engine 14, the transmission 16, the coupling 28, and the like are provided.

  Various information such as signals from an accelerator opening sensor 36, an engine speed sensor 38, a vehicle speed sensor 40, a cruise control switch 42, and an upper limit vehicle speed control switch 44 are input to the control unit 34. The control unit 34 Based on the information, the operations of the engine 14, the transmission 16, the coupling 28, and the like are controlled. Note that the control unit 34 includes a microcomputer as a main part.

  The control unit 34 stores a shift speed map indicating the operation state of the four-wheel drive vehicle 10, specifically, the relationship between the vehicle speed, the accelerator opening, and the shift speed. The control unit 34 stores the shift speed map. The vehicle speed and the accelerator opening are used to control to achieve a predetermined gear position.

  In the four-wheel drive vehicle 10, the control unit 34 starts cruise control when the cruise control switch 42 is changed from the OFF state to the ON state and an ON signal is input from the cruise control switch 42 by the driver's operation, and the driving is started. When the cruise control switch 42 is changed from the ON state to the OFF state by an operator's operation and an OFF signal is input from the cruise control switch 42, the cruise control is stopped. Cruise control is performed by automatically controlling engine output, brakes, and the like.

  In the four-wheel drive vehicle 10, the control unit 34 also starts the upper limit vehicle speed control when the upper limit vehicle speed control switch 44 is changed from the OFF state to the ON state by the driver's operation and the ON signal is input from the upper limit vehicle speed switch 44. When the upper limit vehicle speed control switch 46 is changed from the ON state to the OFF state by the operation of the driver and the OFF signal is input from the upper limit vehicle speed control switch 44, the upper limit vehicle speed control is stopped. The upper limit vehicle speed control is performed by automatically controlling engine output, brakes, and the like.

  The control unit 34 also includes a propeller shaft 30 in which the operation region of the engine 14 extends from the bevel gear to the rear wheel 12R provided on the torque transmission means, specifically, the shaft center of the front wheel differential device 20 in the transfer 22; The torque distribution to the rear wheel 12R is increased by the coupling 28 so as to suppress the generation of abnormal noise when it is in the abnormal noise generation region where the abnormal noise is generated in the drive system including the rear wheel differential device 26 and the like. To control.

  FIG. 2 is a graph showing the relationship between the engine speed, the fluctuation torque of the drive train, and the distribution torque to the rear wheels in the four-wheel drive vehicle. In FIG. 2, the engine rotational speed is taken on the horizontal axis, and the drive system fluctuation torque including the propeller shaft 30 and the rear wheel differential device 26 from the bevel gear to the rear wheel 12R in the transfer 22 and the distributed torque to the rear wheel 12R. Is plotted on the vertical axis, and the waveform of the fluctuation torque of the drive system is indicated by a solid line Wa.

  As shown in FIG. 2, the waveform Wa of the fluctuation torque of the drive system has a peak Pa at a predetermined engine speed Na. FIG. 2 shows the engine speed in the practical range of the engine 14. The waveform Wa of the fluctuation torque corresponds to the waveform W1 of the fluctuation torque shown in FIG. 5, and the peak Pa corresponds to the peak P3 shown in FIG. To do. The practical area of the engine 14 is, for example, an area of the engine speed equal to or higher than the idle speed.

  The control unit 34 includes a predetermined first engine speed N1 including an engine speed Na that is a peak Pa of the waveform Wa of the variable torque, and the first engine speed N1 as an abnormal sound generation region in which the torque transmitting unit is in an abnormal sound generation state. An operation region between a predetermined second engine speed N2 on the higher engine speed side than the one engine speed N1 is set and stored.

In the present embodiment, the first engine speed N1 and the second engine speed N2 are set to the engine speed at which the fluctuation torque of the drive system becomes a predetermined value _TL, and the first engine is used as the abnormal noise generation region. Although an operating region between the rotational speed N1 and the second engine rotational speed N2 is set, it can be set to a predetermined operating region including the engine rotational speed Na.

  The control unit 34 performs the noise suppression control when the operation region of the engine 14 is in the noise generation region, that is, the operation region between the first engine rotation speed N1 and the second engine rotation speed N2. Specifically, the control unit 34 increases the torque distribution to the rear wheel 12R so as to suppress the occurrence of abnormal noise, and exceeds the fluctuation torque of the peak Pa of the waveform Wa as indicated by the solid line L1 in FIG. Control is performed so that the distribution torque T1 to the wheel 12R is obtained.

  In the control unit 34, a waveform Wa of the fluctuation torque of the drive system of the four-wheel drive vehicle 10 is stored, and the relationship between the engine speed for the noise suppression control and the torque distributed to the rear wheels 12R is set. Has been remembered.

  In the present embodiment, when the operation region of the engine 14 is in the abnormal noise generation region, the control unit 34 also shifts to a predetermined operation control that continues the operation region of the engine 14 in the abnormal noise generation region. Transition suppression control is performed. Specifically, when the operation region of the engine 14 is in the abnormal noise generation region, the control unit 34 prohibits the shift to the predetermined operation control that continues the operation region of the engine 14 in the abnormal noise generation region. The transition prohibition control is performed. As the predetermined operation control, cruise control and upper limit vehicle speed control are used.

  FIG. 3 is a flowchart showing control of the four-wheel drive vehicle. In the four-wheel drive vehicle 10, the abnormal noise suppression control and the transition suppression control are executed by the control unit 34. As shown in FIG. 3, the control unit 34 reads various signals from the accelerator opening sensor 36, the engine speed sensor 38, the vehicle speed sensor 40, the cruise control switch 42, the upper limit vehicle speed control switch 44, and the like (step S1). ).

  Next, in step S2, it is determined whether or not the operation region of the engine 14 is an abnormal sound generation region. It is determined whether or not the operation region of the engine 14 is in an abnormal sound generation region, that is, an operation region between the first engine speed N1 and the second engine speed N2.

  If the determination result in step S2 is no (NO), that is, if the operation region of the engine 14 is not an abnormal noise generation region, steps S1 to S2 are repeated.

  On the other hand, if the determination result in step S2 is yes (YES), that is, if it is determined that the operating region of the engine 14 is in the abnormal noise generation region, abnormal noise suppression control is performed (step S3). Specifically, the torque distribution increasing control for increasing the torque distribution to the rear wheel 12R is performed by the coupling 28, and the distribution torque T1 to the rear wheel 12R exceeding the fluctuation torque of the peak Pa of the waveform Wa is controlled. .

  In step S4, when the operation region of the engine 14 is in the abnormal noise generation region, the transition suppression control that suppresses the shift to the predetermined operation control that continues the operation region of the engine 14 in the abnormal noise generation region. I do. Specifically, the cruise control and the upper limit vehicle speed control are used as the predetermined operation control for continuing that the engine operation region is in the abnormal noise generation region, and the transition prohibition for prohibiting the shift to the cruise control and the upper limit vehicle speed control. Take control.

  In the present embodiment, when the operation region of the engine 14 is in the abnormal sound generation region, control is performed so that the cruise control is not executed even when the cruise control switch 42 is switched from the OFF state to the ON state, and the upper limit vehicle speed control switch 44 is Control is performed so that the upper limit vehicle speed control is not executed even when the engine is switched from the OFF state to the ON state.

  Note that when the operation region of the engine 14 is in an abnormal sound generation region where the abnormal torque is generated by the torque transmission means, the torque distribution to the rear wheels 12R is suppressed by the control unit 34 so as to suppress the generation of the abnormal noise. And the transition to predetermined operation control that keeps the operation region of the engine 14 in the abnormal noise generation region when the operation region of the engine 14 is in the abnormal noise generation region. A transition suppression means is configured.

  Thus, in the four-wheel drive vehicle 10 according to the present embodiment, when the operation region of the engine 14 is in the abnormal noise generation region, the predetermined operation that continues the operation region of the engine 14 in the abnormal noise generation region. Since the shift to the control is suppressed, it is possible to prevent the torque distribution to the rear wheel 12R from continuing to be increased so as to suppress the generation of abnormal noise, and the distribution torque to the rear wheel 12R is increased. Thus, it is possible to suppress deterioration in fuel consumption due to the state where the generation of abnormal noise is suppressed for a long time.

  Moreover, the operation control which continues that the driving | running area | region of the engine 14 exists in an abnormal noise generation | occurrence | production area | region by prohibiting the transfer to the predetermined driving | operation control which continues that the driving | operation area | region of the engine 14 exists in an abnormal noise generation | occurrence | production area | region. It is possible to inhibit the shift to the above, and it is possible to suppress the continuation of increasing the torque distribution to the rear wheel 12R so as to suppress the occurrence of abnormal noise.

  In this embodiment, the cruise control and the upper limit vehicle speed control are used as the predetermined operation control for continuing that the operation region of the engine 14 is in the abnormal noise generation region, but the transmission 16 operates the four-wheel drive vehicle 10. It consists of an automatic transmission that can be switched between an automatic transmission mode in which the gear position is automatically switched according to the state and a manual transmission mode in which the gear position is switched by a passenger's manual operation. When the automatic transmission mode control to be performed and the manual transmission mode control to perform the transmission control in the manual transmission mode are configured to be switchable, as predetermined operation control for continuing that the operation region of the engine 14 is in the abnormal noise generation region, Manual shift mode control can also be used.

  Further, when at least one of the cruise control, the upper limit vehicle speed control, and the manual shift mode control is used, and the engine operating region is in the abnormal noise generation region, the cruise control, the upper limit vehicle speed control, and the manual shift mode control are performed. Of these, the transition to at least one control may be suppressed.

  FIG. 4 is a flowchart showing the control of the four-wheel drive vehicle according to the second embodiment of the present invention. The description of the same configuration as the four-wheel drive vehicle 10 according to the first embodiment is omitted for the four-wheel drive vehicle according to the second embodiment.

  In the four-wheel drive vehicle according to the second embodiment, the control unit 34 is a predetermined unit that continues the operation region of the engine 14 in the abnormal noise generation region when the operation region of the engine 14 is in the abnormal noise generation region. Transition suppression control that suppresses transition to operation control is performed. Specifically, the control unit 34 notifies the driver that the engine 14 is in a state in which it is prohibited to shift to a predetermined operation control in which the operation region of the engine 14 is in the abnormal noise generation region. I do.

  The four-wheel drive vehicle has a notification device such as a notification lamp for notifying the driver that the engine 14 is in a state in which it is prohibited to shift to a predetermined operation control in which the operation region of the engine 14 is in the abnormal noise generation region. And the control unit 34 controls the alarm device to operate when the operation region of the engine 14 is in the abnormal sound generation region.

  As shown in FIG. 4, also in the four-wheel drive vehicle according to the second embodiment, when the determination result in step S2 is yes, that is, when it is determined that the operating region of the engine 14 is in the abnormal noise generation region, Abnormal noise suppression control is performed (step S3). Specifically, the torque distribution increasing control for increasing the torque distribution to the rear wheel 12R is performed by the coupling 28, and the distribution torque T1 to the rear wheel 12R exceeding the fluctuation torque of the peak Pa of the waveform Wa is controlled. .

  In step S4, when the operation region of the engine 14 is in the abnormal noise generation region, the transition suppression control that suppresses the shift to the predetermined operation control that continues the operation region of the engine 14 in the abnormal noise generation region. I do. Specifically, the cruise control and the upper limit vehicle speed control are used as the predetermined operation control for continuing that the operation region of the engine 14 is in the abnormal noise generation region, and the transition to the cruise control and the upper limit vehicle speed control is prohibited. The transition prohibition notification control for notifying the driver of the presence of the vehicle is performed.

  In the present embodiment, when the operation region of the engine 14 is in the abnormal sound generation region, a notification device such as a notification lamp that notifies the driver that the shift to the cruise control and the upper limit vehicle speed control is prohibited is activated. To control. For example, as the notification device, the cruise control switch 42 and the upper limit vehicle speed control switch 44 are configured to be lit, and the cruise control switch 42 and the upper limit vehicle speed control switch 44 are set when the operation region of the engine 14 is in the abnormal sound generation region. It can be controlled to light up.

  As described above, also in the four-wheel drive vehicle 10 according to the present embodiment, when the operation region of the engine 14 is in the abnormal noise generation region, the predetermined range of continuing the operation region of the engine 14 in the abnormal noise generation region. Since the shift to the driving control is suppressed, it is possible to prevent the torque distribution to the rear wheel 12R from being continuously increased so as to suppress the generation of abnormal noise, and the distribution torque to the rear wheel 12R can be reduced. It is possible to suppress deterioration in fuel consumption due to the state where the occurrence of abnormal noise is suppressed for a long time.

  In addition, the driver is informed that the engine 14 is in a state of prohibiting the shift to the predetermined operation control in which the operation region of the engine 14 is in the abnormal noise generation region. It is possible to suppress the transition operation to the driving control that continues that the region is in the abnormal noise generation region, and to continue increasing torque distribution to the rear wheel 12R so as to suppress the generation of abnormal noise. It can be suppressed.

  In the first embodiment, the shift to the predetermined operation control is prohibited as the shift suppression control for suppressing the shift to the predetermined operation control for continuing that the operation region of the engine 14 is in the abnormal noise generation region. In the second embodiment, the driver is notified that the shift to the predetermined operation control is prohibited, but the driver is notified that the shift to the predetermined operation control is prohibited. In addition, the shift to the predetermined operation control may be prohibited.

  In the present embodiment, a four-wheel drive vehicle is described in which the front wheels 12F are main drive wheels and the rear wheels 12R are auxiliary drive wheels. However, the rear wheels 12R are main drive wheels and the front wheels 12F are auxiliary drive wheels. The same can be applied to the four-wheel drive vehicle.

  The present invention is not limited to the illustrated embodiments, and various improvements and design changes can be made without departing from the scope of the present invention.

  As described above, according to the present invention, in a four-wheel drive vehicle, the fuel consumption caused by continuing the state where the distribution torque to the auxiliary drive wheels is increased to suppress the generation of abnormal noise for a long time. Therefore, it may be suitably used in the manufacturing industry of this type of vehicle.

10 Four-wheel drive vehicle 12F Front wheel 12R Rear wheel 14 Engine 16 Transmission 18, 24 Axle 20 Front wheel differential 22 Transfer 26 Rear wheel differential 28 Coupling 30 Propeller shaft 34 Control unit 36 Accelerator opening sensor 38 Engine rotation Number sensor 40 Vehicle speed sensor 42 Cruise control switch 44 Upper limit vehicle speed control switch

Claims (4)

An engine, torque transmission means for transmitting output torque of the engine to the main drive wheel and auxiliary drive wheel, and torque distribution means provided in the torque transmission means for adjusting torque distributed to the auxiliary drive wheel among the output torque of the engine The torque distribution adjusting means, and the torque distribution adjusting means so as to suppress the occurrence of abnormal noise when the operating region of the engine is in an abnormal noise generating area where the abnormal torque is generated by the torque transmitting means. A control device for a four-wheel drive vehicle having an abnormal noise suppression means for increasing torque distribution to the auxiliary drive wheels,
When the engine operating region is in the abnormal noise generation region, there is provided transition suppression means for suppressing a shift to predetermined operation control that continues the engine operating region in the abnormal noise generation region. ,
A control device for a four-wheel drive vehicle. The transition suppression means prohibits transition to predetermined operation control that continues the operation region of the engine in the abnormal noise generation region;
The control device for a four-wheel drive vehicle according to claim 1. The transition suppression means informs the driver that the engine is in a state that prohibits transition to predetermined operation control in which the operation region of the engine is in the abnormal sound generation region.
The control device for a four-wheel drive vehicle according to claim 1 or 2, characterized in that The predetermined driving control includes cruise control for controlling the vehicle speed or the inter-vehicle distance to be maintained at a set target value, upper limit vehicle speed control for controlling the vehicle speed so as not to exceed the set upper limit vehicle speed, and manual operation of the occupant Manual shift mode control for controlling the shift of the automatic transmission based on at least one control,
The control device for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein the control device is a four-wheel drive vehicle.

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