JP6007995B2 - Four-wheel drive vehicle control device and four-wheel drive vehicle - Google Patents

Description

  The present invention relates to a control device for a four-wheel drive vehicle and an four-wheel drive vehicle having an engine configured to be switchable between an all-cylinder operation mode and a reduced-cylinder operation mode.

  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.

  In addition, the transfer includes a pair of bevel gears that mesh with each other, more specifically, a front wheel differential, in order to transmit power from a front wheel differential device whose shaft center extends in the vehicle width direction to a propeller shaft that extends 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 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. Drive systems such as the propeller shaft extending from the bevel gear to the rear wheel and the differential device for the rear wheel rotate in a non-power transmission state where 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. 6 is a diagram showing the relationship between the torque fluctuation frequency of the engine of the four-wheel drive vehicle and the two-wheel drive vehicle to which the basic structure corresponds and the transmission characteristic with respect to the torsional vibration of the drive system. Both the waveform of the transmission characteristic with respect to the torsional vibration of the four-wheel drive vehicle shown in FIG. 6 (waveform indicated by the solid line) W1 and the waveform of the transmission characteristic with respect to the torsional vibration of the two-wheel drive vehicle (waveform indicated by the broken line) W2 Although a peak P1, P2 resonance at frequencies below (below the 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, the propeller shaft from the bevel gear to the rear wheel in the transfer and the drive system such as the differential for the rear wheel resonate with the torque fluctuation of the engine to suppress the rattling between the gears. However, in Patent Document 1, for example, in the engine knocking generation region, in order to suppress the occurrence of abnormal noise due to the vibration caused by knocking being transmitted from the transfer to the differential device for the rear wheel, It is disclosed to increase the distribution of output torque.

JP 2001-277881 A

  By the way, in a four-wheel drive vehicle that switches between a two-wheel drive state and a four-wheel drive state, in order to improve the fuel efficiency of the engine, an all-cylinder operation mode in which all of a plurality of cylinders are operated and some of the plurality of cylinders are operated. There has been known one provided with an engine configured to be able to switch between a reduced-cylinder operation mode in which only a cylinder is operated.

  In such a four-wheel drive vehicle, the frequency of engine torque fluctuation differs between the engine all-cylinder operation mode and the reduced-cylinder operation mode even if the engine speed is the same. The engine speed when the driving system such as the propeller shaft to be reached and the rear wheel differential system resonates with the torque fluctuation of the engine is different.

  For example, in a reduced-cylinder operation mode in which two cylinders are deactivated in a four-cylinder engine, the frequency of engine torque fluctuation is half of the frequency of engine torque fluctuation in the all-cylinder operation mode when the engine speed is the same. The engine speed when the drive system resonates with engine torque fluctuation is twice the engine speed when resonating in the all-cylinder operation mode.

FIG. 7 is a diagram showing the relationship between the engine speed and the fluctuation torque of the drive system in the all-cylinder operation mode and the reduced-cylinder operation mode of the four-wheel drive vehicle. As shown in FIG. 7, in a four-wheel drive vehicle equipped with a four-cylinder engine, a waveform (variable waveform shown by a solid line) W11 of the drive system in the all-cylinder operation mode in which the four-cylinder is operated is a practical range of the engine. The lower engine speed (less than the engine speed N _L ) has resonance peaks P11 and P12, and the engine speed in the engine practical range (more than the engine speed N _L ) has a resonance peak P13. In the reduced-cylinder operation mode in which the cylinder is operated, the waveform of the fluctuation torque of the drive system (the waveform shown by a broken line) W12 is an engine speed that is twice the engine speed of the peaks P11, P12, and P13, and the resonance peak P21. P22 and P23 are included.

  Therefore, in the all-cylinder operation mode, the generation of noise is suppressed in the all-cylinder operation mode by increasing the torque distributed to the rear wheels by the coupling in the operation region where the drive system resonates with engine torque fluctuations. Even in the reduced-cylinder operation mode, however, there is a possibility that abnormal noise may occur in an operation region where the drive system resonates with engine torque fluctuations.

  Accordingly, the present invention provides a four-wheel drive vehicle including an engine configured to be able to switch between the all-cylinder operation mode and the reduced-cylinder operation mode. The purpose is to be able to suppress the generation of abnormal noise.

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

  First, an invention according to claim 1 of the present application transmits an engine configured to be able to switch between an all-cylinder operation mode and a reduced-cylinder operation mode, and an output torque of the engine to main drive wheels and auxiliary drive wheels. A torque transmission means, a torque distribution adjusting means provided in the torque transmission means for adjusting a torque distributed to the auxiliary drive wheels among the output torque of the engine; and the torque transmission means in the all-cylinder operation mode of the engine. Four-wheel drive, comprising: noise suppression means for increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the generation of noise when in the first operating region in which an abnormal noise occurs. In the vehicle control device, the abnormal noise suppression unit is configured to transmit the torque in the reduced-cylinder operation mode on the higher engine speed side than the first operation region in the reduced-cylinder operation mode of the engine. The torque distribution adjustment means increases torque distribution to the auxiliary drive wheels so as to suppress the generation of abnormal noise when the stage is in the second operation area including the operation area where abnormal noise is generated. .

  According to a second aspect of the present invention, in the control device for a four-wheel drive vehicle according to the first aspect, in the first operation region, the torque transmission means generates noise in the all-cylinder operation mode of the engine. An operating region between a predetermined first engine rotational speed that is in a state and a predetermined second engine rotational speed higher than the first engine rotational speed, the second operating region being the first An engine operating range between an engine speed and a predetermined third engine speed on a higher engine speed side than the second engine speed, and the noise suppression means is configured to reduce the noise in the reduced-cylinder operation mode of the engine. In the operation region below the engine speed at which the torque distribution to the auxiliary driving wheel is increased so as to suppress the generation of abnormal noise in the two operation regions, the generation of abnormal noise is suppressed in the reduced-cylinder operation mode of the engine. To do Characterized in that to increase the torque distribution for said auxiliary drive wheels from the torque distribution for said auxiliary drive wheels to be increased.

  The invention according to claim 3 is the control device for a four-wheel drive vehicle according to claim 1 or 2, wherein the first operation region is the torque transmission means in the all-cylinder operation mode of the engine. Is an operating range between a predetermined first engine speed at which abnormal noise occurs and a predetermined second engine speed on the higher engine speed side than the first engine speed, and the second operating range is , An operating range between the first engine speed and a predetermined third engine speed on the higher engine speed side than the second engine speed, and the second operating area in the reduced-cylinder operation mode of the engine. When there is a request to shift to the all-cylinder operation mode in the operation region that overlaps with the first operation region, the abnormal noise suppression means is in the first operation region in the all-cylinder operation mode of the engine. sometimes Characterized in that the transition to the all-cylinder operation mode is performed after being adjusted to a torque distribution for said auxiliary drive wheels to be increased so as to suppress the generation of noise.

  The invention according to claim 4 is the control apparatus for a four-wheel drive vehicle according to any one of claims 1 to 3, wherein the first operation region is the all-cylinder operation mode of the engine. The torque transmission means is an operating region between a predetermined first engine speed at which an abnormal sound is generated and a predetermined second engine speed on the higher engine speed side than the first engine speed, The second operation region is an operation region between the first engine speed and a predetermined third engine speed that is higher than the second engine speed and is higher than the second engine speed. When there is a request to shift to the reduced-cylinder operation mode in the operation region on the higher engine speed side than the first operation region in the second operation region, the engine noise reduction means is provided by the noise suppression means. In operation mode Serial shift to the reduced-cylinder operation mode after being adjusted to a torque distribution for said auxiliary drive wheels to be increased so as to suppress the generation of abnormal noise when the second is in the operating region is possible, characterized in that place.

  According to a fifth aspect of the present invention, there is provided an engine configured to be able to switch between the all-cylinder operation mode and the reduced-cylinder operation mode, and torque transmission for transmitting the output torque of the engine to the main drive wheel and the auxiliary drive wheel. Means, torque distribution adjusting means for adjusting the torque distributed to the auxiliary drive wheels among the output torque of the engine, and the torque transmitting means in the all-cylinder operation mode of the engine. A four-wheel drive vehicle having noise suppression means for increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the generation of noise when in the first driving region that is in the generation state. In the reduced-cylinder operation mode of the engine, the abnormal noise suppression means is configured so that the torque transmission means is in an abnormal-noise occurrence state in the reduced-cylinder operation mode on the higher engine speed side than the first operation region. Characterized in that to increase the torque distribution for said auxiliary drive wheels by said torque distributing adjusting means so as to suppress the generation of abnormal noise when in the second operating region including the operating region to be a.

  With the above configuration, according to the first aspect of the present invention, in the all-cylinder operation mode, the generation of abnormal noise is suppressed when the torque transmission means is in the first operation region where the abnormal noise is generated. An abnormal noise suppression means for increasing the torque distribution to the auxiliary drive wheels is provided. In the reduced cylinder operation mode, the abnormal noise suppression means has a torque transmission means in the reduced cylinder operation mode on the higher engine speed side than the first operation region. The torque distribution for the auxiliary drive wheels is increased so as to suppress the generation of abnormal noise when the vehicle is in the second operating area including the operating area where abnormal noise is generated.

  As a result, torque distribution for the auxiliary drive wheels is increased so as to suppress the generation of abnormal noise when the torque transmission means is in the operation region where the abnormal noise generation state occurs in the all-cylinder operation mode and the reduced cylinder operation mode. In a four-wheel drive vehicle equipped with an engine that can be switched between the all-cylinder operation mode and the reduced-cylinder operation mode, the generation of abnormal noise is suppressed in the all-cylinder operation mode and the generation of abnormal noise is suppressed. Can be suppressed.

  According to the second aspect of the present invention, the noise suppressing means has a maximum torque distribution with respect to the auxiliary drive wheels that is increased so as to suppress the generation of noise in the second operation region in the reduced-cylinder operation mode. In the operating region below the engine speed, the torque distribution for the auxiliary drive wheels is increased more than the torque distribution for the auxiliary drive wheels that is increased so as to suppress the generation of noise in the reduced cylinder operation mode. As a result, in the reduced-cylinder operation mode, when the speed of the accelerator pedal by the driver is large and the operation region is changed or switched to the all-cylinder operation mode, the torque to the auxiliary drive wheels is suppressed so as to suppress the generation of abnormal noise. Before the distribution is increased, it is possible to suppress the torque transmission means from being in an abnormal noise generation state, and it is possible to more effectively suppress the generation of abnormal noise.

  According to the invention of claim 3, when there is a request to shift to the all-cylinder operation mode when in the reduced-cylinder operation mode and in the operation region overlapping the first operation region in the second operation region, The shift to the all-cylinder operation mode is performed after the torque distribution to the auxiliary drive wheels that are increased so as to suppress the generation of abnormal noise when in the first operation region in the all-cylinder operation mode is performed. Before the torque distribution for the drive wheels is increased, it is possible to suppress the torque transmission means from being in an abnormal noise generation state, and it is possible to more effectively suppress the generation of abnormal noise.

  According to the fourth aspect of the present invention, when the all-cylinder operation mode is in the operation region on the higher engine speed side than the first operation region in the second operation region, the request for shifting to the reduced-cylinder operation mode is made. If there is, the shift to the reduced-cylinder operation mode is performed after adjusting the torque distribution for the auxiliary drive wheels to be increased so as to suppress the generation of abnormal noise when in the second operation region in the reduced-cylinder operation mode. As a result, it is possible to prevent the torque transmission means from entering an abnormal noise generation state before the torque distribution to the auxiliary drive wheels is increased, and to suppress the generation of abnormal noise more effectively.

  According to the fifth aspect of the present invention, when the torque transmission means is in the first operation region where the abnormal noise is generated in the all-cylinder operation mode, the torque to the auxiliary drive wheels is suppressed so as to suppress the generation of the abnormal noise. An abnormal noise suppression means for increasing the distribution is provided. In the reduced cylinder operation mode, the abnormal noise suppression means is in the reduced cylinder operation mode on the higher engine speed side than the first operation region and the torque transmission means is in the abnormal noise generation state. The torque distribution for the auxiliary drive wheels is increased so as to suppress the generation of abnormal noise when in the second driving region including the driving region.

  As a result, torque distribution for the auxiliary drive wheels is increased so as to suppress the generation of abnormal noise when the torque transmission means is in the operation region where the abnormal noise generation state occurs in the all-cylinder operation mode and the reduced cylinder operation mode. In a four-wheel drive vehicle equipped with an engine that can be switched between the all-cylinder operation mode and the reduced-cylinder operation mode, the generation of abnormal noise is suppressed in the all-cylinder operation mode and the generation of abnormal noise is suppressed. Can be suppressed.

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 graph which shows the relationship between the engine speed in the four-wheel drive vehicle which concerns on 2nd Embodiment of this invention, the fluctuation torque of a drive system, and the distribution torque to a rear wheel. It is a graph which shows the relationship between the engine speed in the four-wheel drive vehicle which concerns on 3rd Embodiment of this invention, the fluctuation torque of a drive system, and the distribution torque to a rear wheel. 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. It is a figure which shows the relationship between the engine speed of the all-cylinder driving mode of a four-wheel drive vehicle, and the reduction-cylinder driving mode, and the fluctuation torque of a drive system.

  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. 16 and a transmission case 17 provided with 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, a transfer 22 that extracts the driving force transmitted to the rear wheels 12R, 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 is provided.

  The engine 14 is a multi-cylinder engine having a plurality of cylinders, specifically, a four-cylinder engine having four cylinders, and an all-cylinder operation mode in which the four cylinders are operated and a reduced cylinder in which the two cylinders are deactivated and the two cylinders are operated. The operation mode can be switched.

  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 the amount of depression of the accelerator pedal (accelerator opening) by the driver, an engine rotation speed sensor 38 that detects the rotation speed of the engine 14, an engine 14 and a cup. And a control unit 34 for controlling the operation of the ring 28 and the like.

  Various information such as signals from the accelerator opening sensor 36 and the engine speed sensor 38 are input to the control unit 34, and the control unit 34 controls the operation of the engine 14 and the coupling 28 based on these various information. To do. Note that the control unit 34 includes a microcomputer as a main part.

  The control unit 34 stores an operation mode map indicating the relationship between the engine speed and the accelerator opening and the operation mode, specifically, the all-cylinder operation mode and the reduced cylinder operation mode. Using the mode map, control is performed so as to switch between the all-cylinder operation mode and the reduced-cylinder operation mode of the engine 14 based on the engine speed and the accelerator opening.

  The control unit 34 also includes a propeller shaft 30 and a rear wheel extending from the bevel gear to the rear wheel 12R provided on the shaft center of the front wheel differential device 20 in the transfer 22 in the all-cylinder operation mode. Control is performed so that the torque distribution to the rear wheel 12R is increased by the coupling 28 so as to suppress the generation of abnormal noise when the drive system such as the wheel differential 26 is in the first operation region where the abnormal noise is generated. To do.

  In the reduced-cylinder operation mode, the control unit 34 includes the operation region in which the torque transmission means, specifically, the drive system is in an abnormal noise generation state in the reduced-cylinder operation mode on the higher engine speed side than the first operation region. Control is performed so as to increase the torque distribution to the rear wheel 12R by the coupling 28 so as to suppress the generation of abnormal noise when in the second driving region.

  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 rotation speed is taken on the horizontal axis, and the fluctuation torque of the drive system such as the propeller shaft 30 and the rear wheel differential 26 from the bevel gear to the rear wheel 12R in the transfer 22 and the distribution torque to the rear wheel 12R are shown. On the vertical axis, the waveform of the fluctuation torque of the drive system in the all-cylinder operation mode is indicated by a solid line Wa, and the waveform of the fluctuation torque of the drive system in the reduced cylinder operation mode is indicated by a broken line Wb.

  As shown in FIG. 2, the fluctuation torque waveform Wa in the all-cylinder operation mode has a peak Pa at a predetermined engine speed Na, and the fluctuation torque waveform Wb in the reduced cylinder operation mode is higher than the engine speed Na. It has a peak Pb at a predetermined engine speed Nb on the engine rotation side.

  FIG. 2 shows the engine speed in the practical range of the engine 14, and the waveform Wa and Wb of the variable torque correspond to the waveforms W11 and W12 of the variable torque shown in FIG. 7, and the peaks Pa and Pb are This corresponds to the peaks P13 and P23 shown in FIG. 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 including an engine speed Na at which the peak Pa of the waveform Wa of the fluctuating torque is provided as a first operation region in which the torque transmitting means is in an abnormal sound generation state in the all-cylinder operation mode. An operating region between the number N1 and a predetermined second engine speed N2 on the higher engine speed side than the first engine speed N1 is set and stored.

  The control unit 34 also includes a variable torque waveform Wb as a second operation region including an operation region in which the torque transmitting means is in an abnormal noise generation state in a reduced cylinder operation mode on the higher engine speed side than the first operation region. An operating region between the first engine speed N1 including the engine speed Nb at the peak Pb and a predetermined third engine speed N3 on the higher engine speed side than the second engine speed N2 is set and stored. ing.

  The control unit 34 controls the noise suppression in the all-cylinder operation mode when the all-cylinder operation mode is in the first operation region, that is, the operation region between the first engine speed N1 and the second engine speed N2. I do. Specifically, the control unit 34 increases the torque distribution to the rear wheel 12R by the coupling 28 so as to suppress the generation of abnormal noise, and the fluctuation of the peak Pa of the waveform Wa as shown by the solid line L1 in FIG. Control is performed so that the distribution torque T1 to the rear wheel 12R exceeds the torque.

  The control unit 34 also performs noise suppression control in the reduced-cylinder operation mode when in the reduced-cylinder operation mode and in the second operation region, that is, the operation region between the first engine speed N1 and the third engine speed N3. Do. Specifically, the control unit 34 increases the torque distribution with respect to the rear wheel 12R by the coupling 28 so as to suppress the generation of abnormal noise, and the fluctuation of the peak Pb of the waveform Wb as indicated by the broken line L2 in FIG. Control is performed so that the distribution torque T1 to the rear wheel 12R exceeds the torque.

  The control unit 34 stores the waveform Wa and Wb of the fluctuation torque of the drive system of the four-wheel drive vehicle 10 and the engine speed for noise suppression control in the all-cylinder operation mode and the reduced cylinder operation mode. The relationship with the distribution torque to the rear wheel 12R is set and stored.

  FIG. 3 is a flowchart showing control of the four-wheel drive vehicle. In the four-wheel drive vehicle 10, abnormal noise suppression control that suppresses generation of abnormal noise by the torque transmission means is executed by the control unit 34. As shown in FIG. 3, the control unit 34 first reads signals detected by the configuration related to the four-wheel drive vehicle 10, that is, various signals such as the accelerator opening and the engine speed (step S1).

  Next, in step S2, it is determined whether or not it is the all-cylinder operation mode. Whether or not the engine 14 is in the all-cylinder operation mode is determined from the engine speed and the accelerator opening, using an operation mode map that shows the relationship between the engine speed and the accelerator opening and the operation mode.

  If the determination result in step S2 is yes (YES), that is, if it is determined that the operation mode is the all-cylinder operation mode, the noise suppression control is performed in the all-cylinder operation mode (step S3), and the first operation is performed in the all-cylinder operation mode. The torque distribution to the rear wheel 12R is increased by the coupling 28 when in the one operation region, and control is performed so that the distribution torque T1 to the rear wheel 12R exceeds the fluctuation torque of the peak Pa of the waveform Wa in the all cylinder operation mode. To do.

  On the other hand, if the determination result in step S2 is no (NO), that is, if it is determined that the reduced-cylinder operation mode is selected instead of the all-cylinder operation mode, abnormal noise suppression control is performed in the reduced-cylinder operation mode (step S4). ) In the reduced-cylinder operation mode, the torque distribution to the rear wheel 12R is increased by the coupling 28 when in the second operation range, and in the reduced-cylinder operation mode, the torque to the rear wheel 12R exceeding the fluctuation torque of the peak Pb of the waveform Wb is increased. Control is performed so that the distributed torque T1 is obtained.

  The control unit 34 also controls the operation of the engine 14 so as to switch between the all-cylinder operation mode and the reduced-cylinder operation mode from the engine speed and the accelerator opening using the operation mode map.

  The control unit 34 increases the torque distribution to the rear wheel 12R by the coupling 28 so as to suppress the generation of abnormal noise when in the first operation region in the all-cylinder operation mode, and in the reduced cylinder operation mode. An abnormal noise suppression means for increasing torque distribution to the rear wheel 12R by the coupling 28 is configured so as to suppress the occurrence of abnormal noise when in the two driving range.

  As described above, in the four-wheel drive vehicle 10 according to the present embodiment, in the all-cylinder operation mode, when the torque transmission unit is in the first operation region where the abnormal noise is generated, the generation of the abnormal noise is suppressed. The noise suppression means 34 for increasing the torque distribution to the wheel 12R is provided, and the noise suppression means 34 is configured to transmit the torque in the reduced cylinder operation mode on the higher engine speed side than the first operation region in the reduced cylinder operation mode. The torque distribution for the rear wheels 12R is increased so as to suppress the generation of abnormal noise when the means is in the second driving area including the driving area where abnormal noise is generated.

  As a result, the torque distribution to the rear wheel 12R is increased so as to suppress the generation of abnormal noise when the torque transmission means is in the operation region where the abnormal noise generation state occurs in the all-cylinder operation mode and the reduced cylinder operation mode. In the four-wheel drive vehicle 10 having the engine 14 configured to be switchable between the all-cylinder operation mode and the reduced-cylinder operation mode, the generation of abnormal noise is suppressed in the all-cylinder operation mode and the abnormal noise is generated in the reduced-cylinder operation mode. Can be suppressed.

  In the present embodiment, as the second operating range, an operating range between the first engine speed N1 and the third engine speed N3 is set, but the second engine speed N2 and the third engine speed are set. It may be set to an operation region between the number N3 and an operation region in which the fluctuation torque of the torque transmitting means is a predetermined value or more, and can be set to a predetermined operation region including the engine speed Nb. Further, the first operation region can also be set to a predetermined operation region including the engine speed Na.

  FIG. 4 is a graph showing the relationship between the engine speed, the fluctuation torque of the drive system, and the distribution torque to the rear wheels in the four-wheel drive vehicle according to the second embodiment of the present invention. The four-wheel drive vehicle according to the second embodiment includes the four-wheel drive vehicle 10 according to the first embodiment and the rear wheels when in the first operation region in the all-cylinder operation mode and the second operation region in the reduced-cylinder operation mode. Since the distribution torque to 12R is the same except that it is different, the description of the same configuration is omitted.

  As shown in FIG. 4, also in the present embodiment, the control unit 34 is in the first operation region, that is, the operation region between the first engine speed N1 and the second engine speed N2 in the all-cylinder operation mode. Occasionally, noise suppression control is performed in the all-cylinder operation mode, and the torque distribution to the rear wheel 12R is increased by the coupling 28 so as to suppress the generation of noise, and the distribution to the rear wheel 12R indicated by the solid line L11 in FIG. Control to become torque.

  The control unit 34 controls the distribution torque T2 to the rear wheels 12R at the first engine speed N1, and the distribution torque to the rear wheels 12R increases as the engine speed increases from the first engine speed N1. The predetermined torque between the first engine speed N1 and the second engine speed N2 up to a second engine speed N2 between the first engine speed N1 and the second engine speed N2 is the distribution torque T1 to the rear wheel 12R. To control.

  The control unit 34 also performs noise suppression control in the reduced-cylinder operation mode when in the reduced-cylinder operation mode and in the second operation region, that is, the operation region between the first engine speed N1 and the third engine speed N3. The torque distribution to the rear wheel 12R is increased by the coupling 28 so as to suppress the occurrence of abnormal noise, and control is performed so that the torque is distributed to the rear wheel 12R indicated by the broken line L12 in FIG.

  The control unit 34 controls the distribution torque T2 to the rear wheels 12R at the first engine speed N1, and the distribution torque to the rear wheels 12R increases as the engine speed increases from the first engine speed N1. The predetermined torque between the first engine speed N1 and the third engine speed N3 to the third engine speed N3 is the distribution torque T1 to the rear wheel 12R. To control.

  Also in the present embodiment, the control unit 34 determines whether or not it is the all-cylinder operation mode, and when it is determined that it is the all-cylinder operation mode, the noise suppression control in the all-cylinder operation mode is performed and reduced. When it is determined that the cylinder operation mode is set, abnormal noise suppression control in the reduced cylinder operation mode is performed. Further, the operation of the engine 14 is controlled by the control unit 34 so as to switch between the all-cylinder operation mode and the reduced-cylinder operation mode from the engine speed and the accelerator opening using the operation mode map.

  As described above, also in the four-wheel drive vehicle 10 according to the present embodiment, in the all-cylinder operation mode, the generation of abnormal noise is suppressed when the torque transmitting means is in the first operation region where the abnormal noise is generated. An abnormal noise suppression means 34 for increasing torque distribution to the rear wheel 12R is provided. The abnormal noise suppression means 34 is in the reduced-cylinder operation mode in the reduced-cylinder operation mode on the higher engine speed side than the first operation region in the reduced-cylinder operation mode. The torque distribution for the rear wheels 12R is increased so as to suppress the generation of abnormal noise when the transmission means is in the second driving area including the driving area where abnormal noise is generated.

  As a result, the torque distribution to the rear wheel 12R is increased so as to suppress the generation of abnormal noise when the torque transmission means is in the operation region where the abnormal noise generation state occurs in the all-cylinder operation mode and the reduced cylinder operation mode. In the four-wheel drive vehicle 10 having the engine 14 configured to be switchable between the all-cylinder operation mode and the reduced-cylinder operation mode, the generation of abnormal noise is suppressed in the all-cylinder operation mode and the abnormal noise is generated in the reduced-cylinder operation mode. Can be suppressed.

  Further, in the four-wheel drive vehicle according to the present embodiment, as compared with the four-wheel drive vehicle according to the first embodiment, the operation range from the first engine speed N1 to the fourth engine speed N4 in the all-cylinder operation mode. Since the distribution torque to the rear wheel 12R and the distribution torque to the rear wheel 12R in the operation range from the first engine speed N1 to the fifth engine speed N5 in the reduced cylinder operation mode can be reduced, the fuel consumption is deteriorated. Can be suppressed.

  Further, the control unit 34 according to the present embodiment is operated in the operation region overlapping the first operation region in the second operation region in the reduced cylinder operation mode, that is, the operation between the first engine speed N1 and the second engine speed N2. If there is a request to shift to the all-cylinder operation mode when in the region, the torque to the rear wheel 12R is increased so as to suppress the generation of abnormal noise when in the first operation region in the all-cylinder operation mode. It is also possible to shift to the all-cylinder operation mode after adjustment to the distribution, that is, after the torque is controlled to the distribution torque to the rear wheel 12R indicated by the solid line L11 in FIG.

  In such a case, it is possible to suppress the torque transmission means from being in an abnormal sound generation state before the torque distribution to the rear wheel 12R is increased, and it is possible to more effectively suppress the generation of abnormal noise. The request for shifting to the all-cylinder operation mode is determined from the engine speed and the accelerator opening using the operation mode map.

  Further, the control unit 34 according to this embodiment is operated in the all-cylinder operation mode in the operation region on the higher engine speed side than the first operation region in the second operation region, that is, the second engine speed N2 and the third engine speed N3. When there is a request to shift to the reduced-cylinder operation mode when it is in the operation region between, the noise is increased so as to suppress the occurrence of abnormal noise when in the second operation region in the reduced-cylinder operation mode. It is also possible to shift to the reduced-cylinder operation mode after adjusting the torque distribution to the rear wheel 12R, that is, after being controlled by the distribution torque to the rear wheel 12R indicated by the broken line L12 in FIG.

  In such a case, it is possible to suppress the torque transmission means from being in an abnormal sound generation state before the torque distribution to the rear wheel 12R is increased, and it is possible to more effectively suppress the generation of abnormal noise. The request to shift to the reduced cylinder operation mode is determined from the engine speed and the accelerator opening using the operation mode map.

  FIG. 5 is a graph showing the relationship between the engine speed, drive system fluctuation torque and rear wheel distribution torque in a four-wheel drive vehicle according to the third embodiment of the present invention. The four-wheel drive vehicle according to the third embodiment is the same as the four-wheel drive vehicle according to the second embodiment except that the distribution torque to the rear wheels 12R is different when in the second operation region in the reduced-cylinder operation mode. Therefore, the description of the same configuration is omitted.

  As shown in FIG. 5, also in the present embodiment, the control unit 34 is in the second operation region, that is, the operation region between the first engine speed N1 and the third engine speed N3 in the reduced-cylinder operation mode. Occasionally, noise suppression control is performed in the reduced-cylinder operation mode, and the torque distribution to the rear wheel 12R is increased by the coupling 28 so as to suppress the generation of the noise, and distribution to the rear wheel 12R indicated by the broken line L22 in FIG. Control to become torque.

  The control unit 34 controls the first engine speed N1 so that the distribution torque T3 is higher than the distribution torque T2 to the rear wheel 12R, and the engine speed increases from the first engine speed N1 to the rear wheel 12R. The distribution torque is controlled to be high, and the control is performed so that the distribution torque T1 to the rear wheel 12R is from the fifth engine speed N5 to the third engine speed N3.

  In the present embodiment, an abnormal noise is generated in the reduced-cylinder operation mode in an operating region of less than the engine speed N5 where the torque distribution to the rear wheel 12R that is increased so as to suppress the occurrence of abnormal noise in the second operating region is maximum. In the operating region from the first engine speed N1 to the fifth engine speed N5, the torque distribution for the rear wheel 12R is increased from the torque distribution for the rear wheel 12R that is increased so as to suppress the occurrence, and in the operating region from the first engine speed N1 to the fifth engine speed N5, the broken line L12 in FIG. Control is performed so that the distribution torque is higher than the distribution torque to the rear wheel 12R indicated by the two-dot chain line L12 in FIG.

  Also in the present embodiment, the control unit 34 determines whether or not it is the all-cylinder operation mode, and when it is determined that it is the all-cylinder operation mode, the noise suppression control in the all-cylinder operation mode is performed and reduced. When it is determined that the cylinder operation mode is set, abnormal noise suppression control in the reduced cylinder operation mode is performed. Further, the operation of the engine 14 is controlled by the control unit 34 so as to switch between the all-cylinder operation mode and the reduced-cylinder operation mode from the engine speed and the accelerator opening using the operation mode map.

  As described above, also in the four-wheel drive vehicle 10 according to the present embodiment, in the all-cylinder operation mode, the generation of abnormal noise is suppressed when the torque transmitting means is in the first operation region where the abnormal noise is generated. An abnormal noise suppression means 34 for increasing torque distribution to the rear wheel 12R is provided. The abnormal noise suppression means 34 is in the reduced-cylinder operation mode in the reduced-cylinder operation mode on the higher engine speed side than the first operation region in the reduced-cylinder operation mode. The torque distribution for the rear wheels 12R is increased so as to suppress the generation of abnormal noise when the transmission means is in the second driving area including the driving area where abnormal noise is generated.

  As a result, the torque distribution to the rear wheel 12R is increased so as to suppress the generation of abnormal noise when the torque transmission means is in the operation region where the abnormal noise generation state occurs in the all-cylinder operation mode and the reduced cylinder operation mode. In the four-wheel drive vehicle 10 having the engine 14 configured to be switchable between the all-cylinder operation mode and the reduced-cylinder operation mode, the generation of abnormal noise is suppressed in the all-cylinder operation mode and the abnormal noise is generated in the reduced-cylinder operation mode. Can be suppressed.

  Further, the abnormal noise suppressing means 34 is operated in an operating region below the engine speed N5 where the torque distribution to the rear wheel 12R is maximized so as to suppress the generation of abnormal noise in the second operating region in the reduced cylinder operating mode. Further, the torque distribution for the rear wheel 12R is increased from the torque distribution for the rear wheel 12R that is increased so as to suppress the occurrence of abnormal noise in the reduced-cylinder operation mode. As a result, in the reduced-cylinder operation mode, the torque applied to the rear wheel 12R is suppressed so as to suppress the generation of abnormal noise when the driver depresses the accelerator pedal and the operation region is changed or switched to the all-cylinder operation mode. Before the distribution is increased, it is possible to suppress the torque transmission means from entering an abnormal noise generation state, and it is possible to more effectively suppress the generation of abnormal noise.

  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, it is possible to suppress the generation of abnormal noise in the all-cylinder operation mode and suppress the generation of abnormal noise in the reduced cylinder operation mode in the four-wheel drive vehicle. There is a possibility of being suitably used in the vehicle manufacturing industry.

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

Claims (5)

An engine configured to be able to switch between the all-cylinder operation mode and the reduced-cylinder operation mode, 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, A torque distribution adjusting means for adjusting a torque distributed to the auxiliary drive wheels among the output torque of the engine, and a first operation region in which the torque transmitting means is in an abnormal noise generation state in the all-cylinder operation mode of the engine. Noise control means for increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the occurrence of abnormal noise, and a control device for a four-wheel drive vehicle,
The abnormal noise suppression means includes a second operation region in which the torque transmission means is in a noise generation state in the reduced cylinder operation mode on the higher engine speed side than the first operation region in the reduced cylinder operation mode of the engine. Increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the occurrence of abnormal noise when in the driving region,
A control device for a four-wheel drive vehicle. The first operating range includes a predetermined first engine speed at which the torque transmitting means is in a noise generating state in the all-cylinder operating mode of the engine, and a predetermined first engine speed higher than the first engine speed. 2 is the operating range between the engine speed and
The second operating region is an operating region between the first engine speed and a predetermined third engine speed on the higher engine speed side than the second engine speed,
The abnormal noise suppression means is an operation less than the engine speed at which the torque distribution to the auxiliary driving wheel is increased so as to suppress the generation of abnormal noise in the second operation region in the reduced-cylinder operation mode of the engine. In the region, the torque distribution for the auxiliary drive wheel is increased from the torque distribution for the auxiliary drive wheel that is increased so as to suppress the occurrence of noise in the reduced-cylinder operation mode of the engine.
The control device for a four-wheel drive vehicle according to claim 1. The first operating range includes a predetermined first engine speed at which the torque transmitting means is in a noise generating state in the all-cylinder operating mode of the engine, and a predetermined first engine speed higher than the first engine speed. 2 is the operating range between the engine speed and
The second operating region is an operating region between the first engine speed and a predetermined third engine speed on the higher engine speed side than the second engine speed,
When there is a request for transition to the all-cylinder operation mode when the engine is in the operation region overlapping the first operation region in the second operation region in the reduced-cylinder operation mode of the engine, the abnormal noise suppression means causes the engine to The shift to the all-cylinder operation mode is performed after the torque distribution for the auxiliary drive wheels is adjusted to be increased so as to suppress the occurrence of abnormal noise when in the first operation region in the all-cylinder operation mode.
The control device for a four-wheel drive vehicle according to claim 1 or 2, characterized in that The first operating range includes a predetermined first engine speed at which the torque transmitting means is in a noise generating state in the all-cylinder operating mode of the engine, and a predetermined first engine speed higher than the first engine speed. 2 is the operating range between the engine speed and
The second operating region is an operating region between the first engine speed and a predetermined third engine speed on the higher engine speed side than the second engine speed,
In the all-cylinder operation mode of the engine, when there is a request to shift to the reduced-cylinder operation mode in the operation region on the higher engine speed side than the first operation region in the second operation region, When the torque distribution for the auxiliary drive wheels is adjusted to be increased so as to suppress the generation of abnormal noise when the suppression means is in the second operation region of the engine in the reduced-cylinder operation mode, The transition takes place,
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. An engine configured to be able to switch between the all-cylinder operation mode and the reduced-cylinder operation mode, 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, A torque distribution adjusting means for adjusting a torque distributed to the auxiliary drive wheels among the output torque of the engine, and a first operation region in which the torque transmitting means is in an abnormal noise generation state in the all-cylinder operation mode of the engine. Noise suppression means for increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the occurrence of abnormal noise, and a four-wheel drive vehicle,
The abnormal noise suppression means includes a second operation region in which the torque transmission means is in a noise generation state in the reduced cylinder operation mode on the higher engine speed side than the first operation region in the reduced cylinder operation mode of the engine. Increasing torque distribution to the auxiliary drive wheels by the torque distribution adjustment means so as to suppress the occurrence of abnormal noise when in the driving region,
A four-wheel drive vehicle characterized by this.

Images