JPH0976779A - Torque distribution controller of four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly distribute torque from an engine to front and rear wheels on an ascending slope. SOLUTION: Torque from an engine 1 is directly transmitted through a transmission 2 to front wheels and further through a transfer 4 to rear wheels 9. A controller 20 includes a driving shaft torque calculating part 40 for calculating torque applied to a front wheel drive shaft 8a, a slope calculating part 50 for calculating the slope of the place of traveling, a transmitted torque calculating part 29 for correcting basic transmitted torque and causing the corrected basic transmitted torque to be target transmitted torque according to drive shaft torque Td calculated by the drive shaft torque calculating part 40 and a slope θ calculated by the slope calculating part 50 and a hydraulic control valve 5 for operating the transfer 4 according to the objective transmitted torque calculated by the transmitted torque calculating part 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a four-wheel drive vehicle,
The present invention relates to a torque distribution control device for a four-wheel drive vehicle that controls torque distribution between front and rear wheels.

[0002]

2. Description of the Related Art In a four-wheel drive vehicle, a method for controlling the torque distribution between the front and rear wheels is to control the hydraulic pressure of a hydraulic multi-plate clutch so that the four-wheel drive vehicle can be driven from the direct four-wheel drive state to the front wheel drive (FF).
There is a torque split system that can change the state or the rear wheel drive (FR) state. In terms of running performance, a direct-coupled four-wheel drive that can obtain torque distribution according to the ground load of the tire is ideal, but in the situation where there is a difference in rotation between the front and rear wheels, torque cross occurs, which adversely affects fuel efficiency. . Therefore, in such a torque split system, when high running performance is required, use the direct-coupled four-wheel drive side with the best power characteristics, and if the driving force is relatively small, such as during steady driving, It is on the FF side or FR side to prevent deterioration.

The control of this system is performed by the automobile technology Vo.
l. 41, No. As described in "4. Driving force distribution control technology for four-wheel drive vehicles", the driving force is predicted by the gear position, vehicle speed, and throttle during normal driving, and the transmission torque is determined using the map prepared in advance. ing. Further, in the prior art, if the transmission torque cannot be obtained using the detection value of the vehicle speed sensor due to an accidental failure, for example, the vehicle speed sensor fails, high running even if the fuel consumption deteriorates a little. The direct drive four-wheel drive mode is adopted to obtain the desired characteristics.

[0004]

In the above-mentioned prior art, the driving force change due to the road gradient change is not taken into consideration only by the driving force prediction based on the gear position, the vehicle speed and the throttle. There is a problem that it cannot be communicated. Further, in the related art, if any one of the plurality of sensors that detect the value required to determine the transmission torque fails, the direct-connection four-wheel drive state is immediately established, and the fuel consumption deteriorates.

Therefore, a first object of the present invention is to provide a torque distribution control device for a four-wheel drive vehicle capable of transmitting an appropriate driving force to each wheel even when climbing a slope. A second object of the present invention is a four-wheeled vehicle that can achieve both running performance and fuel efficiency to some extent even if one of a plurality of sensors that detects a value required to determine transfer torque of a transfer fails. A torque distribution control device for a driving vehicle is provided.

[0006]

A torque distribution control device for a four-wheel drive vehicle for achieving the above-mentioned first object comprises a front wheel (8) after a torque from an engine (1) is passed through a transmission (2). ) And the rear wheel (9), the transfer (4) can be transmitted to one wheel (8) through various shafts and the transmission torque can be arbitrarily changed to the other wheel (9). And a four-wheel drive vehicle that further transmits via various shafts, transmission (2)
In the torque distribution control device for controlling the transfer (4) so that the transmission torque transmitted from the other wheel to the other wheel (9) becomes the target transmission torque, the output shaft of the transmission (2) or the transmission (2) and the above Drive shaft torque grasping means (13, 14,) for grasping a torque (hereinafter referred to as a drive shaft torque) applied to any of the various shafts connected to one wheel (8).
15, 23, 40), a gradient grasping means (11, 22, 50) for grasping the gradient of the place where the vehicle is traveling, and a rotation difference grasping means (11, 22, for grasping a rotation difference between the front wheel and the rear wheel).
22 and 25), and a basic transmission torque calculating means (26) for obtaining a basic transmission torque which is basic in the calculation of the target transmission torque and which is determined according to the rotation difference obtained by the rotation difference grasping means, and the drive. Using a first correlation that defines a relationship between the shaft torque and a first correction amount for correcting the basic transmission torque according to the drive shaft torque,
A first correction amount calculation means (27) for obtaining the first correction amount for the drive shaft torque grasped by the drive shaft torque grasping means, the gradient, and for correcting the basic transmission torque according to the gradient. A second correction amount calculation means (28) for obtaining the second correction amount for the gradient grasped by the gradient grasping means by using a second correlation in which the relation with the second compensation amount is predetermined. Target transfer torque calculating means (29) for correcting the basic transfer torque using the first correction amount and the second correction amount, and using the corrected basic transfer torque as the target transfer torque, and the transfer. Transfer operation means (5) for operating the transfer (4) so that the transfer torque of (4) becomes the target transfer torque obtained by the target transfer torque calculating means. The one in which the features.

Here, in the above torque distribution control device, the first correlation is such that, when the drive shaft torque is larger than a predetermined value, the first correction amount increases as the drive shaft torque increases. It is preferable that the relationship also increases. Further, it is preferable that the second correlation is a relationship in which when the gradient is larger than a predetermined value, the second correction amount also increases as the gradient increases. Further, the basic transmission torque calculation means (26) is
The basic transmission torque may be obtained by subtracting a value obtained by multiplying the rotation difference by a constant from a predetermined transmission torque.

Further, in the above torque distribution control device, the drive shaft torque grasping means is the output shaft of the transmission (2) or the transmission (2).
It may be a torque sensor that detects a torque applied to any of the various shafts connected to the one wheel (8).

Further, the drive shaft torque grasping means has an engine rotation speed detecting means (14) for detecting the rotation speed of the engine, an amount of air entering the engine, or an air having a correlation with the amount of air. An intake air amount detecting means (13) for detecting an equivalent physical quantity, and a torque ratio grasping means (41, 41) for grasping a torque ratio (t × r) which is a ratio between the current input torque and output torque of the transmission (2).
42, 23, 47), the amount of air or the air-equivalent physical amount, the engine speed, and the output shaft torque of the engine, and the predetermined correlation is detected by the intake air amount detecting means. Engine output shaft torque calculation means (46) for obtaining the engine output shaft torque corresponding to the amount of air or the air-equivalent physical amount and the engine speed detected by the engine speed detection means, and the engine output torque Drive shaft torque calculating means for obtaining the drive shaft torque by multiplying the engine output shaft torque obtained by the calculating means by the torque ratio (t × r) of the transmission (2) grasped by the torque ratio grasping means (49a) may be included.

Further, the drive shaft torque grasping means includes a torque converter (2a) in which the transmission (2) is connected to the engine (1), and a stepped transmission mechanism (in which the transmission (2) is connected to the torque converter (2a). 2b), the engine speed detecting means (14) for detecting the speed of the engine (1) and the torque converter (2).
The torque converter output shaft speed detecting means (15) for detecting the output shaft speed of a) and the gear ratio grasping means (23) for grasping the current speed ratio (r) of the stepped speed change mechanism (2b).
And the engine rotation speed, the torque converter output shaft torque rotation speed, and the input shaft torque of the torque converter (2a), which are determined in advance by the engine rotation speed detection means (14). Torque converter input shaft torque calculating means (41, 43, 44) for obtaining the torque converter input shaft torque corresponding to the engine speed and the torque converter output shaft speed detected by the torque converter output shaft speed detecting means. , 4
5) and a predetermined correlation between the engine speed, the torque converter output shaft torque speed, and the torque ratio of the torque converter (2a), are detected by the engine speed detecting means (14). A torque ratio calculating means (41, 42) for obtaining the torque ratio corresponding to the engine speed and the torque converter output shaft speed detected by the torque converter output shaft speed detecting means.
And the torque converter input shaft torque obtained by the torque converter input shaft torque calculating means, the torque ratio obtained by the torque ratio calculating means, and the gear shift being grasped by the gear ratio grasping means (23). Multiply the ratio,
Drive shaft torque calculating means for obtaining the drive shaft torque.

The predetermined correlation between the engine speed, the torque converter output shaft torque speed, and the torque ratio, which is used when the torque ratio of the torque converter (2a) is obtained, includes the engine speed and the torque converter output. It also includes a relation indirectly representing the relation between the engine rotation speed, the torque converter output shaft torque rotation speed and the torque ratio, such as the relation between the slip ratio e and the torque ratio t, which are the ratios to the shaft torque rotation speed. In addition, when the input shaft torque of the torque converter (2a) is used, the predetermined correlation between the engine speed, the torque converter output shaft torque speed, and the torque converter input shaft torque includes the engine speed and the torque. The relationship between the slip ratio e, which is the ratio of the converter output shaft torque rotation speed, and the capacity coefficient λ of the torque converter (e-λ
(Characteristic relationship), the capacity coefficient λ determined from this relationship is multiplied by the square of the engine speed Ne ² , and the correlation between the engine speed, the torque converter output shaft torque speed, and the torque converter input shaft torque is indirectly determined. The relationship expressed in is also included.

Further, the drive shaft torque grasping means includes a torque converter (2a) in which the transmission (2) is connected to the engine (1), and a stepped transmission mechanism connected to the torque converter (2a). And (2b), the engine rotation speed detection means (14) for detecting the rotation speed of the engine (1) and the amount of air entering the engine (1), or a correlation with the amount of air. Intake air amount detecting means (13) for detecting a related physical quantity of air, torque converter output shaft rotating speed detecting means (15) for detecting an output shaft rotating speed of the torque converter (2a), and the stepped type A gear ratio grasping means (23) for grasping the current gear ratio of the transmission mechanism, and an amount of the air or a physical amount equivalent to the air, the engine speed and an output shaft torque of the engine in advance. Using the above correlation, the amount of air detected by the intake air amount detecting means or the air-equivalent physical quantity and the engine speed detected by the engine speed detecting means (14) An engine output shaft torque calculating means (46) for obtaining an engine output shaft torque, the engine speed, the torque converter output shaft torque speed, and the torque converter (2a).
Of the engine speed detected by the engine speed detecting means (14) and the torque converter output detected by the torque converter output shaft speed detecting means using a predetermined correlation with the input shaft torque of Torque converter input shaft torque calculating means (41, 43, 4) for obtaining the torque converter input shaft torque corresponding to the shaft rotation speed
4, 45) and the engine output shaft torque calculating means (4
6) the engine output shaft torque and the torque converter input shaft torque calculating means (41, 43, 4)
4, 45), the input torque of the torque converter, one of which is the input shaft torque of the transmission (2), the input shaft torque selecting means (48), and the engine speed. The engine speed detected by the engine speed detecting means (14) and the torque converter output using the predetermined correlation between the torque converter output shaft speed and the torque ratio of the torque converter (2a). Torque ratio calculation means (41, 4) for obtaining the torque ratio corresponding to the torque converter output shaft rotation speed detected by the shaft rotation speed detection means.
2), the transmission input shaft torque obtained as a result of selection by the input shaft torque selecting means (48), the torque ratio (t) obtained by the torque ratio calculating means (41, 42), and the Gear ratio grasping means (23)
Drive shaft torque calculation means (49a) for multiplying the speed change ratio (r) obtained in step 1 to obtain the drive shaft torque.

Further, in the above torque distribution control device, the gradient grasping means includes a vehicle speed detecting means (11) for detecting the speed of the vehicle and an acceleration detecting means (11, 22) for detecting the longitudinal acceleration of the vehicle. And the speed detected by the vehicle speed detecting means (11) to obtain a running resistance torque of the vehicle on a flat surface, and the acceleration detecting means (11, 22).
The acceleration resistance torque of the vehicle is obtained by using the acceleration detected in step S1, and the level running resistance torque and the acceleration resistance torque are subtracted from the drive axis torque obtained by the drive axis torque grasping means to obtain a gradient resistance. Gradient calculation means (50) for obtaining torque and for obtaining the gradient using the gradient resistance torque
And may be included.

Further, the gradient grasping means has a gyro sensor for detecting a pinch angular velocity of the vehicle, and an integrator for integrating the pinch angular velocity detected by the gyro sensor to obtain the gradient. May be

Further, the slope grasping means has a position grasping means for grasping the current driving position, and the driver is based on the driving position grasped by the position grasping means and the road information stored in advance. The vehicle may further include navigation means indicating the current driving position and gradient calculating means for calculating the gradient based on the road information at the current driving position indicated by the navigation means.

Further, in the above torque distribution control device, the rotation difference grasping means is detected by the acceleration detecting means (11, 22) for detecting the longitudinal acceleration of the vehicle and the acceleration detecting means (11, 22). The front wheel load applied to the front wheel and the rear wheel load applied to the rear wheel are respectively calculated from the calculated acceleration, the slope acquired by the slope acquisition means (50), and the vehicle weight, and the wheel load stored in advance is stored. Using the elastic coefficient, the dynamic radius of the front wheel when the front wheel load is applied to the front wheel and the dynamic radius of the rear wheel when the rear wheel load is applied to the rear wheel are obtained, A rotation difference calculating means (25) for obtaining the rotation difference by using the difference between the radius vector and the radius vector of the rear wheel may be provided.

Further, in the above torque distribution control device, the drive shaft torque grasping means (13, 14, 15, 2).
3, 40), the gradient grasping means (11, 22, 50), and the rotation grasping means (11, 22, 25), when any of them fails, a failure determining means (21) for grasping the details of the failure. ) And a target transmission torque calculation means (30) at the time of failure for obtaining the target transmission torque according to the content of the failure.
And the transfer operation means (5), when the failure target transfer torque calculating means (30) obtains the target transfer torque, the transfer torque of the transfer (4) is changed to the target transfer torque. The transfer (4) may be operated so that

Further, a torque distribution control device for a four-wheel drive vehicle for achieving the second object is one of a front wheel and a rear wheel after a torque from the engine (1) is passed through a transmission (2). , A four-wheel drive vehicle that transmits to one wheel via various shafts and further transmits to the other wheel via transfer shafts (4) that can arbitrarily change the transmission torque and various shafts, In a torque distribution control device for controlling the transfer (4) so that the transmission torque transmitted from the transmission (2) to the other wheel becomes a target transmission torque,
A plurality of detecting means (11, 12, 13, respectively) for detecting a plurality of values necessary for obtaining the target transmission torque.
14 and 15) and a plurality of detection values detected by a plurality of detecting means, the target transmission torque calculating means (22, 23, 25 to 29, 4) for calculating the target transmission torque.
0, 50, 32), a failure determination means (21) for determining whether each of the plurality of detection means has failed, and the failure determination means for performing a predetermined detection among the plurality of detection means. When it is determined that any of the detecting means other than the means (11, 13) has failed, the detection value (V, T) detected by the predetermined detecting means (11, 13).
vo) and the target transmission torque using a predetermined relationship (hereinafter, referred to as a detection value-target value relationship), the detection value (11, 13) detected by the predetermined detection means (11, 13). V, Tvo) to obtain the target transmission torque,
When the failure determination means determines that any one of the detection means including the predetermined detection means (11, 13) has failed, the detected value-target value relationship is determined. Using the detection value detected by the predetermined detection means, the target transmission torque calculation means at failure for obtaining the target transmission torque according to the value (V, Tvo) determined depending on the situation as a fail-safe condition (30,
32), and when the target transmission torque is calculated by the normal target transmission torque calculating means, the target transmission torque is set as a target value, and the target transmission torque is calculated by the failure target transmission torque calculating means. A transfer operating means (5) for operating the transfer (4) so that the transfer torque of the transfer (4) becomes the target value when the target transfer torque is obtained as a target value. It is characterized by that.

In the torque distribution control device for a four-wheel drive vehicle for achieving the second object, a plurality of the detecting means (11, 12, 13, 14, 15) are used for the air flowing into the engine (1). Or an intake air amount detecting means (13) for detecting an air-equivalent physical quantity that is correlated with the amount of air, and a vehicle speed detecting means (1) for detecting the speed of the vehicle.
1), the predetermined detection means includes the intake air amount detection means (13) and the vehicle speed detection means (11).
The detected value-target value relationship is the vehicle speed detected by the vehicle speed detection means (11) and the amount of air detected by the intake air amount detection means (13) or the air-equivalent physical quantity. The relationship with the target transmission torque may be determined.

In the above, the numbers in parentheses are
It is the number of the corresponding part of the embodiment described below.

[0021]

In the control device for achieving the first object, the torque distribution ratio between the front wheels and the rear wheels is determined according to the rotation difference between the front and rear wheels, the drive shaft torque, and the road gradient. Specifically, when the driving force is required and the driving shaft torque is large, the road gradient is large, or the rotation difference between the front and rear wheels is small,
The transfer torque of the transfer becomes large, and it becomes close to the direct-coupled four-wheel drive state. For example, when the vehicle is climbing uphill, an appropriate driving force can be transmitted to each wheel. Further, when the driving force is unnecessary and the driving shaft torque is small, the road gradient is small, or the rotation difference between the front and rear wheels is large, the transfer torque of the transfer becomes small and becomes close to the FF side or the FR side. Torcross can be kept small.

A torque sensor that directly detects the torque applied to the shaft by means of a scale is extremely expensive. Therefore, based on the detected value of the engine speed detection means,
When the drive shaft torque is calculated, the manufacturing cost of the device can be significantly reduced.

Further, in the control device for achieving the second object, a predetermined detecting means among a plurality of detecting means for respectively detecting a plurality of values necessary for obtaining the target transmission torque is used. When it is determined that any one of the detection means other than the above has failed, a predetermined relationship between the detected value detected by the predetermined detection means and the target transmission torque in the failure target transmission torque calculation means (Less than,
Detected value-target value relationship. ) Is used to obtain the target transmission torque according to the detection value detected by the predetermined detection means. Further, when it is determined that any one of the detection means including the predetermined detection means has failed, the predetermined detection is performed using the detection value-target value relationship. Regarding the detection value detected by the means, the target transmission torque is obtained according to a value determined depending on the situation as a fail-safe condition. If all of the plurality of detecting means have not failed, the normal target transmission torque calculating section uses the plurality of detection values detected by the plurality of detecting means to obtain the target transmission torque.

As described above, even if one of the plurality of sensors for detecting the value required to determine the transmission torque fails, the direct-coupled four-wheel drive state is not immediately established, and the sensor that has not failed is used. The obtained information is used to determine the target transmission torque that can achieve both running performance and fuel efficiency to some extent.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a four-wheel drive vehicle according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the four-wheel drive vehicle of this embodiment has an engine 1, an automatic transmission (hereinafter referred to as AT) 2 connected to an output shaft of the engine 1, and a pair of front wheels. 8,8 and a pair of front wheels 8,8
Front-wheel-side drive shaft 8a that couples each other and a pair of rear wheels 9 and 9
And a rear-wheel-side drive shaft 9a for connecting the pair of rear wheels 9, 9 to each other
And a front wheel side propeller shaft 6a that is directly connected to the output shaft of the AT2, and a front wheel side differential gear 6 that connects the front wheel side propeller shaft 6a and the front wheel side drive shaft 8a.
The transfer torque from the front wheel side propeller shaft 6a can be arbitrarily changed, the transfer 4 is composed of a hydraulic multi-disc clutch, the rear wheel side propeller shaft 7a connected to the output shaft of the transfer 4, and the rear wheel. A rear wheel differential gear 7 that connects the wheel propeller shaft 7a and the rear wheel drive shaft 9a, a hydraulic control valve 5 that operates the transfer 4, and various sensors 11, ..., 15
And a controller 20 that executes various controls.

In the intake pipe for sending air to the engine 1,
A throttle valve 1a is provided. The throttle valve 1a has a valve opening degree Tv of the throttle valve 1a.
A throttle sensor 12 for detecting o is provided.
The crankshaft of the engine 1 is provided with a crank angle sensor 14 that detects the rotation speed Ne of the engine output shaft. The AT 4 has a torque converter 2a directly connected to the output shaft of the engine 1 and a stepped gear train 2b directly connected to the output shaft of the torque converter 2a. The torque converter 2a is provided between the pump directly connected to the output shaft of the engine 1, the turbine directly connected to the input shaft of the stepped transmission gear train 2b, and oil between the pump and the turbine. It has a stator. The turbine of the torque converter 2a is provided with a turbine sensor 15 that detects the rotation speed Nt of the turbine. The accelerator pedal 3 operated by the driver is
An accelerator pedal sensor 12 that detects the operation amount A is provided. A vehicle speed sensor 11 that detects the vehicle speed V is provided on the front wheel drive shaft 8a. The vehicle speed sensor 11 actually detects the rotation speed of the front wheel drive shaft 8a.

The controller 20 has a microcomputer, and controls the AT 4 and the hydraulic control valve 5 for operating the transfer 4. The controller 20 time-differentiates the vehicle speed V detected by the vehicle speed sensor 11 and a failure determination unit 21 that determines whether or not each sensor 11, ... The vehicle speed sensor 1 is calculated using the calculation unit 22 and a gear position map stored in advance.
1 and a gear position setting unit 23 that determines a gear position Gp corresponding to the accelerator pedal operation amount A detected by the accelerator pedal sensor 12, and an output shaft torque that determines a torque Td of the front wheel side drive shaft 8a. Arithmetic unit 4
0 and the gradient calculator 5 that obtains the gradient θ of the place where the vehicle is traveling
0, the rotation difference calculation unit 25 for obtaining the rotation difference Δω between the front wheels 8 and the rear wheels 9, and the rotation difference Δω obtained by the rotation difference calculation unit 25.
And a first correction amount for obtaining a first correction amount ΔTc of the basic transmission torque Tco corresponding to the drive shaft torque Td obtained by the output shaft torque calculation unit 40. The basic transmission torque Tc corresponding to the gradient θ calculated by the calculator 28 and the gradient calculator 50
Second correction amount calculation unit 27 for obtaining second correction amount ΔTcω of o
And a normal-time transmission torque calculation unit 29 that corrects the basic transmission torque Tco by using the first correction amount ΔTc and the second correction amount ΔTcω to obtain the target transmission torque Tc, and the failure determination unit 21.
If it is determined that any of the sensors has failed, the failure transmission torque calculation unit 30 for obtaining the target transmission torque Tc at the time of the failure, and any transmission torque calculation unit 2
The operation amount conversion unit 32 for converting the target transmission torque Tc obtained in steps 9 and 30 into the operation amount Pc of the hydraulic control valve 5.

The above is the software configuration of the controller 20, and in terms of hardware, a CPU for executing various calculations, various maps, various data, and CP.
RO in which programs etc. for U to be stored are stored
M, a RAM for temporarily storing various data and the like,
It is configured to have an A / D converter or the like for converting an analog signal from each sensor into a digital signal suitable for CPU calculation.

In the above, in order to obtain the acceleration of the vehicle, the acceleration calculating section 22 for obtaining the acceleration α by time-differentiating the vehicle speed V detected by the vehicle speed sensor 11 is provided, but instead, the acceleration sensor is provided. Good. Further, both the acceleration calculation unit 22 and the acceleration sensor may be provided, and when one of the vehicle speed sensor 11 and the acceleration sensor fails, the other sensor may be used as a backup sensor. When the vehicle speed sensor 11 fails, the vehicle speed may be obtained using the turbine speed Nt and the gear ratio r of the AT4. Further, when the turbine sensor 15 fails, the turbine speed Nt may be obtained using the vehicle speed V and the gear ratio r of the AT4.

Here, how to determine the front wheel side drive shaft torque Td by the drive shaft torque calculation unit 40 will be described with reference to FIG. First, the divider 41 calculates the turbine rotation speed Nt detected by the turbine sensor 15 into the crank angle sensor 14
The slip ratio e (= Nt / Ne) of the torque converter is obtained by dividing by the engine speed Ne detected in. As shown in FIG. 4, the torque ratio calculation unit 42 uses a map showing the relationship between the slip ratio e and the torque ratio t of the mounted torque converter 2a to determine the slip ratio e previously obtained. Find the corresponding torque ratio t. Further, in the capacity coefficient calculation unit 43, as shown in FIG. 4, the slip ratio previously obtained is calculated using a map showing the relationship between the slip ratio e of the mounted torque converter 2a and the capacity coefficient λ. The capacity coefficient λ (= Tp / Ne ² ) corresponding to e is obtained. The multiplier 44 squares the engine speed Ne detected by the crank angle sensor 14. In the multiplier 45,
The pump torque Tp is calculated by multiplying the capacity coefficient λ calculated by the capacity coefficient calculation unit 43 by Ne ² calculated by the multiplier 44.
Find (= λ · Ne ² ).

In parallel with the above calculation of the pump torque Tp, the engine torque calculating section 46 indicates the relationship among the engine speed Ne, the throttle opening Tvo and the engine output shaft torque Te as shown in FIG. Using the existing map, the engine output shaft torque Te corresponding to the engine speed Ne detected by the crank angle sensor 14 and the throttle opening Tvo detected by the throttle sensor 13 is obtained. Note that, here, in order to obtain the engine output shaft torque Te, the engine speed Ne and the throttle opening Tv
Although a map showing the relationship between o and the engine output shaft torque Te is used, instead of the throttle opening in this map, the intake air amount supplied from the intake pipe to the engine 1 that has a correlation with this value, Alternatively, the fuel injection amount to the engine 1 may be used. In this case, the throttle sensor 13
Instead of this, it goes without saying that an intake air amount sensor or the like for detecting the amount of air supplied from the intake pipe to the engine 1 will be provided.

By the way, since the output shaft of the engine 1 and the pump of the torque converter 2a are directly connected, the torque applied to both is actually the same. Therefore, the pump torque Tp calculated by the multiplier 45 and the engine output shaft torque Te calculated by the engine torque calculation unit 46 should have the same value. However, when the engine output shaft torque Te is calculated using a map showing the relationship among the engine speed Ne, the throttle opening Tvo, and the engine output shaft torque Te, this engine torque T
In e, for example, there is an air conditioner as an auxiliary machine, and when the air conditioner is driven, there is a disadvantage that the torque reduction due to the driving of the air conditioner is not reflected. Therefore, the engine output shaft torque (or pump torque) is obtained by two different methods, and either one is set as the input torque Tin of the AT2 depending on the situation. The input torque selection unit 48 selects which of the pump torque Tp calculated by the multiplier 45 and the engine output shaft torque Te calculated by the engine torque calculation unit 46 to be the input torque Tin of AT2.
Is the turbine speed N detected by the turbine sensor 15.
Based on t, the engine speed Ne detected by the crank angle sensor 14, and the slip ratio e obtained by the divider 41, the operating condition is judged and performed.

The gear ratio calculating section 47 converts the gear position Gp set by the gear position setting section 23 into a gear ratio r using a map. The input torque Tin output from the input torque selection unit 48 is multiplied by the torque ratio t calculated by the torque ratio calculation unit 42 and the gear ratio r calculated by the gear ratio calculation unit 47 in the multiplier 49a, The torque of the front wheel side propeller shaft 6a is obtained. To this torque
The multiplier 49c multiplies the gear ratio rf of the front wheel side differential gear 6 to obtain the torque Td of the front wheel side drive shaft 8a.

In this way, in the method of estimating the drive shaft torque Td from the output values from the plurality of sensors, for example, the intake air amount Qa and the throttle opening Tvo, the turbine speed Nt and the vehicle speed V, and the like are mutually replaceable. Even if one of the two sensors fails, the drive shaft torque Td can be obtained. Further, as another method for obtaining the drive shaft torque Td, there is a method in which a torque sensor is arranged on the front wheel side drive shaft 8a and is directly obtained from this torque sensor.

Next, how to obtain the gradient by the gradient calculator 50 will be described with reference to FIG. The front wheel side drive shaft torque Td is, as shown in (Equation 1), a flatland running resistance torque T
It is an added value of r, the acceleration resistance torque Tα, and the gradient torque Tθ.

Td = Tr + Tα + Tθ (Equation 1) Further, the flatland traveling resistance torque Tr, Acceleration resistance torque Tα,
The gradient torque Tθ is (Equation 2), (Equation 3),
It is represented by (Equation 4). Tr = (μr · W + ka · V ² ) · R ····· (Equation 2) Tα = (W + Wk) · α · R / g ・ ・ ・(Equation 3) Tθ = W · sin θ · R・ ・ ・ ・ ・ ・ ・ ・ ・ (Equation 4) where μr: rolling frictional resistance coefficient, W: actual vehicle weight, k
a: air resistance coefficient, R: tire radius, Wk: rotational inertia weight, g: gravitational acceleration.

Therefore, first, the flat surface running resistance torque Tr and the acceleration resistance torque Tα are obtained by (Equation 2) and (Equation 3), and are obtained by the drive shaft torque calculation unit 40 as shown in (Equation 5). The gradient sin θ can be obtained by subtracting these torques Tr and Tα from the front wheel side drive shaft torque Td to obtain the gradient torque Tθ and substituting the gradient torque Tθ into (Equation 4).

Tθ = Td−Tr−Tα (Equation 5) Therefore, the present implementation In the example, the actual vehicle weight estimation unit 51 estimates the actual vehicle weight, that is, the actual vehicle weight W. This actual vehicle weight estimation unit 51
The estimation of the actual actual vehicle weight W will be described later. Subsequently, the flatland running resistance torque calculation unit 52 uses the actual vehicle weight W and the vehicle speed V detected by the vehicle speed sensor 11 to obtain the flatland running resistance torque Tr according to (Equation 2). Further, the acceleration resistance torque calculation unit 53 calculates the acceleration resistance torque Tα according to (Equation 3) using the actual vehicle weight W and the acceleration α calculated by the acceleration calculation unit 22. Then, from the drive shaft torque Td obtained by the drive shaft torque calculation unit 40, a subtracter 55
Then, the level running resistance torque Tr is subtracted, and the acceleration resistance torque Tα is subtracted by the subtractor 56 to obtain the gradient torque Tθ.
Finally, the gradient calculator 56 calculates the gradient sin θ according to (Equation 4).

Other methods for estimating the gradient include a method of detecting the angular velocity in the pitch direction with a sensor capable of measuring the pinch angular velocity (for example, a vibration gyro sensor) and integrating the value, or a GPS (Global Positioning System).
There is a method of obtaining latitude information from a signal such as, and a method of obtaining it from the time difference, and a method of directly using the road information if the map information used for navigation has a road gradient.

Next, a method of estimating the actual vehicle weight W by the actual vehicle weight estimating section 51 will be described. (Equation 6) is obtained by substituting (Equation 2), (Equation 3) and (Equation 4) into (Equation 5) which is the basic equation for gradient estimation.

Td = {μr · W + ka · V ² + W · sin θ + (W + Wk) · α / g} · R ······· (Equation 6) Assuming that the drive is performed at time t1 The axis torque is Td ₁ , the gradient is θ ₁ , the vehicle speed is V ₁ , the acceleration is α _1, and the driving axis torque at another time t2 is Td ₂ , the gradient is θ ₂ , the vehicle speed is V ₂ , and the acceleration is α ₂ . At this time, if the following condition 1 is satisfied, the actual vehicle weight W can be estimated from (Equation 7) by subtracting (Equation 6) indicating the state at time t2 from (Equation 6) indicating the state at time t1.

Td ₁ = Td ₂ and θ ₁ = θ ₂ and V ₁ ≠ V ₂ and α ₁ ≠ α ₂ ... Condition 1 W = (V ₂ ² −V ₁ ² ) / (Α ₁ −α ₂ ) · ka · g−Wk ··· (Equation 7) If the above calculation is repeatedly executed at a predetermined timing, Condition 1 can be easily satisfied on a road with a slope. Since it is considered that the condition is satisfied, the actual vehicle weight W can be estimated with high frequency. However, when the condition 1 is not satisfied, the most general vehicle weight is used. In the above calculation, the actual vehicle weight W is calculated using the gradient, and the gradient calculation unit 50 described above calculates the gradient using the actual vehicle weight W.
At the beginning of these calculations, either one must be decided first. Therefore, here, at the start of the calculation, the weight of only the predetermined vehicle body plus the weights of two adults is used as the temporary vehicle weight. Then, the subsequent estimation of the actual vehicle weight is repeated to improve the accuracy of the estimated value of the actual vehicle weight. In addition, as a matter of course, in another method, for example, in the case of obtaining the road gradient by the gyro sensor, the actual vehicle weight W can be easily calculated by (Equation 4).
Is required.

Next, the rotation difference Δω by the rotation difference calculation unit 25.
I will explain how to obtain. First, in FIG. 4, the rotation difference Δ
A method for obtaining the vehicle weight distribution on the front and rear wheels 8 and 9 which is the main cause of ω will be described. FIG. 4 is a diagram showing the force acting on the vehicle in a static state. In the figure, P is the center of gravity of the vehicle, F is the driving force, W is the vehicle weight, a is the distance between the front wheels and the vehicle center of gravity in the horizontal direction, s is the distance between the front wheels and the rear wheels, and h is the contact surface and the vehicle center of gravity. It represents the distance from. First, considering the static ground load distribution, the static load Wf applied to the front wheel 8 and the static load Wr applied to the rear wheel 9 are each expressed by (Equation 8).
It can be expressed by (Equation 9).

Wf = (1-a / s) W ... (Equation 8) Wr = (A / s) ······· (Equation 9) Next, acceleration / deceleration Considering the dynamic ground load distribution at the time, the load moves according to the acceleration during acceleration / deceleration. Therefore, the loads Wf ′ and Wr ′ of the front and rear wheels 8 and 9 at the time of acceleration can be expressed by (Equation 10) and (Equation 11) when the moving load at the time of acceleration is positive. Wf '= Wf-ΔW (Equation 10) Wr' = Wr + ΔW (Equation 11) where ΔW in (Equation 10) and (Equation 11) Is
It can be expressed by (Equation 12).

ΔW = F · (h / s) = W · (α / g) · (h / s) ··· (Equation 12) Next, consider the ground load distribution according to the road gradient. The gradient is θ
Amount of load movement ΔWθ when ゜ (the climb is positive)
Is represented by (Equation 13). ΔWθ = W · sin θ · (h / s) ···· (Equation 13) Therefore, the static load distribution during climbing is (Equation 14) It can be expressed by (Equation 15).

Wfθ = Wf−ΔWθ (Equation 14) Wrθ = Wr + ΔWθ (Equation 15) From the above, the front and rear wheels 8 in consideration of dynamic load movement and gradient load movement , 9 becomes (Equation 16) (Equation 17). ΣWf = Wf−ΔW−ΔWθ (Equation 16) ΣWr = Wr + ΔW + ΔWθ (Equation 17) Here, ΔW can be obtained by substituting the acceleration α obtained by the acceleration calculation unit 22 into (Equation 12), ΔWθ
Can be obtained by substituting sin θ obtained by the gradient calculation unit 50 into (Equation 13), and therefore load distribution in consideration of dynamic load movement and gradient load movement is obtained from (Equation 16) (Equation 1).
It can be obtained in 7).

Next, a method for obtaining the rotation difference Δω between the front and rear wheels from the vehicle weight distribution obtained above will be described with reference to FIGS. 7 and 8. FIG. 7 shows the relationship between the load applied to the tire when stationary and the amount of radial deflection of the tire. Although it shows a slightly distorted characteristic in a region where there is almost no load, when the vehicle weight is normally applied, the deflection occurs almost in proportion to the vehicle weight. The amount of deflection is the same as the reduction in tire radius. Therefore, regarding the relationship between the tire radius and the load, if the radius without a load is Rt ₀ (Equation 1)
It can be represented by 8). In (Equation 18), kt ₁ is a proportional constant.

Rt = Rt ₀ −kt ₁ · W (Equation 18) Here, the tire rotates. In consideration of the fact that the apparent load becomes smaller due to the centrifugal force in the case of the above, the strain of the tire radius can be rewritten from (Equation 18) to (Equation 19).

Rt = Rt ₀ −kt ₁ · (W−kt ₂ · V ² ) ... (Equation 19) FIG. 8 shows the relationship between the vehicle speed and the radius vector of the tire. It is shown. The dynamic radius of the tire here varies depending on the type and characteristics of the tire, and can be considered as the upper limit of the tire radius Rt. Therefore, the tire radii Rtf and Rtr of the front and rear wheels are obtained from (Equation 19) and FIG. 8, and as shown in (Equation 20), the vehicle speed V is set to the tire radius difference (Rtf-Rtr) between the front and rear wheels.
The rotation difference Δω can be obtained by dividing by.

Δω = V / (Rtf−Rtr) (Equation 20) As another method for obtaining the rotation difference, A vehicle speed sensor (such as a rotation pulse meter using a magnetic pickup) may be attached to each of the front wheels 8 and the rear wheels 9 and the difference may be obtained from the difference between the output values from the two vehicle speed sensors.

Next, the operation of the controller 20 of this embodiment will be described with reference to the flow chart shown in FIG. First, in step 1, a signal from each sensor is input. In step 2, the failure determination unit 21 determines whether or not one of the signals from each sensor has a signal abnormality. If there is even one abnormality, the process proceeds to step 14, and if there is no abnormality at all, the process proceeds to step 3. However, of the plurality of sensors, as described above, for example, the intake air amount sensor that detects the intake air amount Qa and the throttle opening Tv
throttle sensor 13 for detecting o, turbine speed N
In the case where one of the two sensors that are in a mutually substitutable relationship such as the turbine sensor 15 that detects t and the vehicle speed sensor 11 that detects the vehicle speed V has failed and the other sensor has not failed , The following processing is executed assuming that there is no sensor failure. In Steps 3, 4, and 5, the drive shaft torque calculation unit 40 calculates the drive shaft torque Td, the slope calculation unit 50 calculates the slope θ, and the rotation difference calculation unit 25 calculates the rotation difference Δω. It

In step 6, the basic transmission torque calculation unit 2
At 6, the basic transmission torque Tco is obtained. In this calculation of the basic transmission torque Tco, the absolute value of the rotation difference | Δω obtained in step 5 is calculated from the predetermined transmission torque Tcb.
│ multiplied by a constant kc (kc││Δω│) subtracted,
The basic transmission torque Tco is calculated. Therefore, the basic transmission torque Tco obtained here becomes smaller as the rotation difference Δω increases.

In step 7, the first correction amount calculation section 28 makes the first comparison between the drive shaft torque Td and the first correction amount ΔTc.
Using the map showing the correlation, the first correction amount ΔTc for the drive shaft torque Td obtained in step 3 is obtained. The first correlation is a relationship in which when the drive shaft torque Td is larger than a predetermined value, the first correction amount ΔTc also linearly increases as the drive shaft torque Td increases. In step 8, in the second correction amount calculation unit 27,
Using the map showing the second correlation between the gradient θ and the second correction amount ΔTcθ, the second correction amount ΔTcθ with respect to the gradient θ obtained in step 4 is obtained. This second correlation is
If the slope θ is larger than a predetermined value, this slope θ
The second correction amount ΔTcθ also linearly increases with increasing.

In step 9, the normal transmission torque calculating unit 29 calculates the basic transmission torque Tc obtained in step 6.
The target transmission torque Tc (= Tco + ΔTc + ΔTcθ) is obtained by adding the first correction amount ΔTc obtained in step 7 and the second correction amount ΔTcθ obtained in step 8 to o.
In step 10, it is judged whether or not the target transmission torque Tc obtained in step 9 is larger than a predetermined upper limit value Tcx of the target transmission torque. If it is larger than the upper limit value Tcx, in step 11, this upper limit value Tcx is determined. Is the target transmission torque Tc. In step 12, it is determined whether the target transmission torque Tc obtained in step 9 is smaller than a predetermined lower limit value Tcn of the target transmission torque. If smaller than the lower limit value Tcn, in step 13,
This lower limit value Tcn is set as the target transmission torque Tc. In addition,
The processes in steps 10 to 13 described above are also executed by the normal time transmission torque calculation unit 29, as in step 9.

In step 2, it is judged that any one of the signals from the respective sensors is abnormal, and when the process proceeds to step 14, the vehicle speed sensor 1
1 and the throttle sensor 13 are abnormal, and if these sensors 11 and 13 are abnormal, the process proceeds to step 15. If these sensors 11 and 13 are normal, step 16 is immediately performed. Proceed to. Note that the determination in step 14 is also performed by the failure determination unit 21 as in the determination in step 2. Also in the determination in step 14, similarly to the determination in step 2, the intake air amount sensor for detecting the intake air amount Qa, the throttle sensor 13 for detecting the throttle opening Tvo, the turbine sensor 15 for detecting the turbine speed Nt, and the vehicle speed. If only one of the two sensors, such as the vehicle speed sensor 11 that detects V, which are in a mutually substitutable relationship, fails, the other one of the sensors is treated as if it has not failed.

In step 15, the abnormal transmission torque calculation unit 30 determines the throttle opening Tvo and the vehicle speed V determined by the fail-safe condition of AT2. Step 1
In 6, the abnormal transmission torque calculation unit 30 determines the target transmission torque Tc in the abnormal state using a map that defines the relationship between the throttle opening Tvo, the vehicle speed V, and the target transmission torque Tc. At this time, if the vehicle speed sensor 11 and the throttle sensor 13 are normal, these sensors 11,
The target transmission torque Tc corresponding to the vehicle speed V and the throttle opening Tvo detected in 13 is obtained, and if the vehicle speed sensor 11 and the throttle sensor 13 are abnormal, the target transmission torque Tc is determined according to the vehicle speed V and the throttle opening Tvo determined in step 15. The target transmission torque Tc is calculated.

In step 17, the manipulated variable converting section 32 operates the target transmission torque Tc in the normal state obtained in steps 9 to 13 or the transmission torque Tc in the abnormal state obtained in step 16 to operate the hydraulic control valve 5. The operation amount Pc is converted to the amount Pc, and this operation amount Pc is output to the hydraulic control valve 5, and the process ends. When the hydraulic control valve 5 is driven by the operation amount and the transfer 4 constituted by the hydraulic multi-plate clutch operates, the torque from the transmission 2 is transmitted to the rear wheels 9, 9 by the target transmission torque.

As described above, in this embodiment, since the road gradient and the like are taken into consideration when determining the torque distribution of the front and rear wheels, for example, a sufficient driving force can be obtained even while climbing a slope. Further, in this embodiment, the drive shaft torque is estimated based on the data from a plurality of various sensors without using a very expensive torque sensor, so that the manufacturing cost can be suppressed. Furthermore, if any of the multiple sensors that detect the value required to determine the transmission torque fails, the data will not be immediately set to the direct-drive four-wheel drive state, and the data obtained from the sensor that has not failed or the failure will occur. By using the data obtained from the sensor that can replace the sensor, the transmission torque that is compatible with both the driving force and the fuel consumption is obtained, so even if one of the multiple sensors fails,
It is possible to prevent the fuel consumption from being extremely deteriorated.

[0060]

According to the present invention, the road gradient and the like are taken into consideration when determining the torque distribution of the front and rear wheels.
A sufficient driving force can be obtained even while climbing a slope.

Further, according to another invention, even if one of the plurality of sensors for detecting the value required for determining the transmission torque fails, the direct-coupled four-wheel drive state does not immediately occur, and the failure occurs. Since the transmission torque that can achieve both the driving force and the fuel consumption is obtained using the data obtained from a sensor that does not exist, even if one of the multiple sensors fails,
It is possible to prevent the fuel consumption from being extremely deteriorated.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a torque distribution control device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram of a drive shaft torque calculation unit according to an embodiment of the present invention.

FIG. 3 is a functional block diagram of a gradient calculation unit according to an embodiment of the present invention.

FIG. 4 is a graph showing characteristics of a torque converter.

FIG. 5 is a graph showing an output torque characteristic of the engine.

FIG. 6 is an explanatory diagram for explaining load distribution between the front wheels and the rear wheels in the embodiment according to the present invention.

FIG. 7 is a graph showing the relationship between the amount of tire deflection and the load.

FIG. 8 is a graph showing the relationship between vehicle speed and tire radius of gyration.

FIG. 9 is a flowchart showing the operation of the controller according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Automatic transmission, 2a ... Torque converter, 2b ... Stepped gear train, 3 ... Accelerator pedal, 4 ... Transfer, 5 ... Hydraulic control valve, 6 ... Front wheel side differential gear, 6a
... front wheel side propeller shaft, 7 ... rear wheel side differential gear, 7a ... rear wheel side propeller shaft, 8 ... front wheel, 8
a ... front wheel drive shaft, 9 ... rear wheel, 9a ... rear wheel drive shaft, 11 ...
Vehicle speed sensor, 12 ... Accelerator pedal sensor, 13 ... Throttle sensor, 14 ... Engine speed sensor, 15 ... Turbine sensor, 20 ... Controller, 21 ... Failure determination unit, 22 ... Acceleration calculation unit, 23 ... Gear position setting unit, 25 Rotational difference calculation unit, 26 ... Basic transmission torque calculation unit, 27 ... Second correction amount calculation unit, 28 ... First correction amount calculation unit, 29 ... Normal transmission torque calculation unit, 30 ... Failure transmission torque calculation unit, 32 ... Manipulation amount conversion unit, 40 ... Drive shaft torque calculation unit, 48 ... Input torque selection unit, 50 ... Gradient calculation unit, 51 ... Weight estimation unit, 52 ... Level running resistance torque calculation unit, 53 ... Acceleration resistance torque calculation unit 53, 56 ... Gradient calculation unit.

Claims (16)

[Claims] 1. A torque from an engine is transmitted to a front wheel and a rear wheel of a front wheel and a rear wheel and then transmitted to the other wheel through various shafts, and the transmission torque is arbitrarily changed to the other wheel. In a four-wheel drive vehicle that further transmits through a transfer and various shafts, a torque distribution control device that controls the transfer so that the transmission torque transmitted from the transmission to the other wheel becomes a target transmission torque. A drive shaft torque grasping means for grasping a torque (hereinafter, referred to as a drive shaft torque) applied to either the output shaft of the transmission or the various shafts connecting the transmission and the one wheel. , A gradient grasping means for grasping a gradient of a place where the vehicle is traveling, and a rotation between the front wheel and the rear wheel. A rotation difference grasping means for grasping a rotation difference, and a basic transmission torque computing means for obtaining a basic transmission torque which is basic in the calculation of the target transmission torque and which is determined according to the rotation difference obtained by the rotation difference grasping means, The relationship between the drive shaft torque and the first correction amount for correcting the basic transmission torque according to the drive shaft torque is grasped by the drive shaft torque grasping means by using a predetermined first correlation. Further, the relationship between the first correction amount calculating means for obtaining the first correction amount for the drive shaft torque, the gradient, and the second correction amount for correcting the basic transmission torque according to the gradient is predetermined. Using second correction amount calculation means for obtaining the second correction amount for the gradient grasped by the gradient grasping means using the second correlation, and the first compensation amount and the second compensation amount, Basic biography A target transfer torque calculating means for correcting the reaching torque and making the corrected basic transfer torque the target transfer torque; and the transfer torque of the transfer is the target transfer torque calculated by the target transfer torque calculating means. And a transfer operating means for operating the transfer, and a torque distribution control device for a four-wheel drive vehicle. 2. The torque distribution control device for a four-wheel drive vehicle according to claim 1, wherein the first correlation is associated with an increase in the drive shaft torque when the drive shaft torque is larger than a predetermined value. hand,
A torque distribution control device for a four-wheel drive vehicle, wherein the first correction amount is also large. 3. The torque distribution control device for a four-wheel drive vehicle according to claim 1, wherein the second correlation is associated with an increase in the gradient when the gradient is larger than a predetermined value. The second
A torque distribution control device for a four-wheel drive vehicle, characterized in that the correction amount is also large. 4. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2 or 3, wherein the basic transmission torque calculating means multiplies the rotation difference by a constant from a predetermined transmission torque. And subtract
A torque distribution control device for a four-wheel drive vehicle, characterized in that the basic transmission torque is obtained. 5. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2, 3 or 4, wherein the drive shaft torque grasping means is an output shaft of the transmission, or the transmission and the one wheel. A torque distribution control device for a four-wheel drive vehicle, which is a torque sensor for detecting a torque applied to any of the various shafts connected to each other. 6. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2, 3 or 4, wherein the drive shaft torque grasping means is an engine speed detecting means for detecting an engine speed. Intake air amount detection means for detecting the amount of air entering the engine or an air-equivalent physical amount that correlates with the amount of air, and a torque ratio that is the ratio of the current input torque and output torque of the transmission And a torque ratio grasping means that uses the predetermined correlation between the air quantity or the air equivalent physical quantity, the engine speed, and the output shaft torque of the engine. An engine for determining the engine output shaft torque corresponding to the amount of air or the air-equivalent physical amount and the engine speed detected by the engine speed detecting means. Drive shaft torque for obtaining the drive shaft torque by multiplying the engine output shaft torque obtained by the engine output torque calculation device by the torque ratio obtained by the torque ratio grasping device. A torque distribution control device for a four-wheel drive vehicle, comprising: a computing unit. 7. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2, 3 or 4, wherein the transmission is a torque converter connected to the engine, and a stepped device connected to the torque converter. And a drive shaft torque grasping means, the drive shaft torque grasping means detects an engine rotation speed of the engine, and a torque converter output shaft rotation detecting an output shaft rotation speed of the torque converter. Number detecting means, speed change ratio grasping means for grasping the current speed change ratio of the stepped speed change mechanism, and predetermined setting of the engine speed, the torque converter output shaft torque speed and the torque converter input shaft torque. Using the above correlation, the engine speed detected by the engine speed detection means and the torque converter output shaft speed detection Torque converter input shaft torque calculating means for obtaining the torque converter input shaft torque corresponding to the torque converter output shaft rotational speed detected at a stage, the engine speed, the torque converter output shaft torque rotational speed, and the torque converter Using a predetermined correlation with the torque ratio of, the engine speed detected by the engine speed detection means and the torque converter output shaft speed detected by the torque converter output shaft speed detection means Torque ratio calculating means for calculating the torque ratio corresponding to the torque converter input shaft torque calculated by the torque converter input shaft torque calculating means, the torque ratio calculated by the torque ratio calculating means, and the shift The drive shaft torque is obtained by multiplying the speed change ratio grasped by the ratio grasping means. A torque distribution control device for a four-wheel drive vehicle, comprising: 8. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2, 3 or 4, wherein the transmission is a torque converter connected to the engine, and a stepped device connected to the torque converter. In the case of having an automatic transmission mechanism, the drive shaft torque grasping means has an engine rotation speed detecting means for detecting the rotation speed of the engine, and an amount of air entering the engine, or a correlation with the amount of air. Intake air amount detecting means for detecting a physical quantity equivalent to air, torque converter output shaft rotational speed detecting means for detecting the output shaft rotational speed of the torque converter, and the current gear ratio of the stepped speed change mechanism are grasped. Using a gear ratio grasping means and a predetermined correlation between the air amount or the air-equivalent physical amount, the engine speed, and the output shaft torque of the engine, , An engine output shaft torque for obtaining the engine output shaft torque corresponding to the amount of the air detected by the intake air amount detection unit or the air-equivalent physical amount and the engine speed detected by the engine speed detection unit The engine rotation speed detected by the engine rotation speed detection means by using a predetermined correlation between the engine rotation speed, the torque converter output shaft torque rotation speed, and the torque converter input shaft torque. And a torque converter input shaft torque calculation means for obtaining the torque converter input shaft torque corresponding to the torque converter output shaft rotation speed detected by the torque converter output shaft rotation speed detection means, and the engine output shaft torque calculation means. The calculated engine output shaft torque and the torque converter input shaft torque Input shaft torque selection means for using one of the torque converter input shaft torques obtained by the calculation means as the input shaft torque of the transmission, the engine speed and the torque converter output shaft speed. And the torque converter output detected by the torque converter output shaft rotation speed detection means by using a predetermined correlation between the torque ratio of the torque converter and the torque ratio of the torque converter. Torque ratio calculation means for obtaining the torque ratio corresponding to the shaft rotation speed, and the transmission input shaft torque obtained as a result of selection by the input shaft torque selection means, the torque ratio obtained by the torque ratio calculation means. , And the drive shaft torque by multiplying the gear ratio grasped by the gear ratio grasping means. Drive shaft torque calculating means and a torque distribution control device for a four wheel drive vehicle, characterized in that it has a seeking. 9. A method according to claim 1, 2, 3, 4, 5, 6, 7 or 8.
In the torque distribution control device for a four-wheel drive vehicle described above, the gradient grasping means includes a vehicle speed detecting means for detecting a vehicle speed, an acceleration detecting means for detecting an acceleration in a longitudinal direction of the vehicle, and the vehicle speed detecting means. The flat running resistance torque of the vehicle is obtained using the speed thus obtained, the acceleration resistance torque of the vehicle is obtained using the acceleration detected by the acceleration detecting means, and the drive shaft obtained by the drive shaft torque grasping means is obtained. A gradient calculating means for calculating the gradient resistance torque by subtracting the flatland running resistance torque and the acceleration resistance torque from the torque, and calculating the gradient using the gradient resistance torque. Torque distribution control device for four-wheel drive vehicles. 10. The torque distribution control device for a four-wheel drive vehicle according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the gradient grasping means detects a pinch angular velocity of the vehicle. And an integrator that obtains the gradient by integrating the pinch angular velocity detected by the gyro sensor, and a torque distribution control device for a four-wheel drive vehicle. 11. The torque distribution control apparatus for a four-wheel drive vehicle according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the gradient grasping means grasps a current driving position. A navigation means for indicating the current driving position to the driver based on the driving position grasped by the position grasping means and the road information stored in advance, and a current driving position indicated by the navigation means. And a gradient calculating unit that obtains the gradient based on the road information in (4), and a torque distribution control device for a four-wheel drive vehicle. 12. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the torque distribution control device for a four-wheel drive vehicle according to 8, 9, or 10, the rotation difference grasping means includes an acceleration detecting means for detecting an acceleration in a longitudinal direction of the vehicle, and the acceleration detected by the acceleration detecting means. The front wheel load applied to the front wheel and the rear wheel load applied to the rear wheel are respectively calculated from the gradient and the vehicle weight grasped by the gradient grasping means, and the front wheels are stored by using the elastic coefficients of the wheels stored in advance. To determine the radius of movement of the front wheel when the front wheel load is applied to the front wheel and the radius of the rear wheel when the rear wheel is applied to the rear wheel. A rotation difference calculation means for obtaining the rotation difference using a difference from a radius, and a torque distribution control device for a four-wheel drive vehicle. 13. The method of claim 1, 2, 3, 4, 5, 6, 7,
In the torque distribution control device for a four-wheel drive vehicle according to 8, 9, 10, 11 or 12, when any one of the drive shaft torque grasping means, the gradient grasping means and the rotation grasping means fails, A failure determining means for grasping a failure content, and a failure target transfer torque calculating means for obtaining the target transfer torque according to the failure content, wherein the transfer operating means has the failure target transfer torque calculating means. The torque distribution control device for a four-wheel drive vehicle, wherein when the target transfer torque is obtained, the transfer is operated so that the transfer torque of the transfer becomes the target transfer torque. 14. After transmitting a torque from an engine through a transmission, one of the front wheels and the rear wheels is further transmitted through various shafts, and the transmission torque is arbitrarily changed to the other wheel. In a four-wheel drive vehicle that further transmits through a transfer and various shafts, a torque distribution control device that controls the transfer so that the transmission torque transmitted from the transmission to the other wheel becomes a target transmission torque. In, the target transmission torque is calculated using a plurality of detection means for detecting a plurality of values required to obtain the target transmission torque and a plurality of detection values detected by the plurality of detection means. Normal-time target transmission torque calculation means, failure determination means for determining whether each of the plurality of detection means has failed, and Among the plurality of detection means, the failure determination means,
When it is determined that any one of the detection means other than the predetermined detection means has failed, a predetermined relationship between the detection value detected by the predetermined detection means and the target transmission torque (hereinafter , Detection value-target value relationship)), the target transmission torque corresponding to the detection value detected by the predetermined detection means is obtained, If any of the detection means including the predetermined detection means is determined to have failed, the detection value detected by the predetermined detection means using the detection value-target value relationship. With respect to, regarding the fail-safe condition, the target transmission torque is obtained by the failure target transmission torque calculating means for obtaining the target transmission torque and the normal time target transmission torque calculating means according to the value determined depending on the situation. In this case, the target transmission torque is set as a target value, and when the target transmission torque is calculated by the failure target transmission torque calculating means, the target transmission torque is set as a target value, and the transfer torque of the transfer is set as a target value. And a transfer operating means for operating the transfer so that the target value becomes the target value, and a torque distribution control device for a four-wheel drive vehicle. 15. The torque distribution control device for a four-wheel drive vehicle according to claim 14, wherein any two of the plurality of detecting means have one of the specific detecting means in order to obtain the target transmission torque. Even if a failure occurs and a detection value cannot be obtained from the other one, the other detection value can be substituted, and the failure determination means is one of the two specific detection means.
A torque distribution control device for a four-wheel drive vehicle, characterized in that if one of them fails, the other does not. 16. The torque distribution control device for a four-wheel drive vehicle according to claim 14 or 15, wherein the plurality of detection means correspond to the amount of air entering the engine or the air corresponding to the amount of air. Intake air amount detecting means for detecting a physical quantity, and a vehicle speed detecting means for detecting the speed of the vehicle, the predetermined detecting means is the intake air amount detecting means and the vehicle speed detecting means, the detected value The target value relationship defines the relationship between the vehicle speed detected by the vehicle speed detection means, the amount of air detected by the intake air amount detection means or the air equivalent physical quantity, and the target transmission torque. A torque distribution control device for a four-wheel drive vehicle.