JP4853079B2 - Vehicle weight detection device for vehicle with fluid coupling - Google Patents

Description

  The present invention relates to a vehicle weight detection device for detecting the weight of a vehicle in a vehicle having a fluid coupling between an engine and a transmission.

  As a trend of vehicles in recent years, in order to facilitate vehicle driving or reduce driver fatigue, power transmission devices for vehicles intended for easy driving, represented by so-called automatic vehicles (AT vehicles), have been spreading. . The AT vehicle has an automatic transmission that combines a torque converter and a planetary gear mechanism, and switches the gear stage according to the running state of the vehicle by a shift command signal output from a vehicle electronic control device such as a computer. .

  Recently, a parallel-shaft gear mechanism type transmission similar to a so-called manual vehicle (MT vehicle) is used as a vehicle power transmission device for easy drive, and a fluid coupling (fluid coupling) is provided between the engine and the transmission. ) Is put into practical use, and such a power transmission device is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-241546. The fluid coupling is a fluid transmission device similar to the torque converter, but does not include a stator and is a simple device correspondingly, although there is no torque amplification function. When the fluid coupling is interposed, it is possible to start using slippage between the pump of the fluid coupling and the turbine when the vehicle starts. That is, a delicate clutch operation is not required when starting an MT vehicle, and a smooth start can be easily performed. At the same time, engine torque fluctuations during idling are absorbed, and vibration and noise are reduced. In a vehicle power transmission device in which a fluid coupling is interposed between an engine and a parallel shaft gear mechanism type transmission, an actuator for operating the parallel shaft gear mechanism type transmission is installed, and a shift command from the vehicle electronic control unit is installed. In many cases, a signal is automatically switched according to the driving state of the vehicle according to the signal.

  When automatically switching the gear stage by the vehicle electronic control unit, it is necessary to switch at the optimum time while monitoring the vehicle running state. Normally, an automatic transmission unit corresponds to the vehicle speed and the amount of depression of the accelerator pedal. To determine the gear position. However, it is desirable to consider the vehicle weight as a parameter for determining the optimum shift time in a truck or the like in which the vehicle weight during traveling greatly changes according to the cargo load. The vehicle weight is a parameter that should be considered for good control not only in the automatic shift speed control device but also in, for example, roll control or yaw control of the vehicle for the purpose of improving running stability.

  In order to detect the vehicle weight, there is a method of measuring the displacement of a spring provided in the suspension of the vehicle. This method is a method for directly detecting the vehicle weight, but requires a stroke sensor for measuring the displacement. In addition, the measurement results include errors due to the unavoidable variations in spring characteristics of suspension springs and the fact that the amount of spring displacement varies depending on the cargo loading location on trucks and other loading platforms. Therefore, the method of measuring the displacement of the suspension spring is not always satisfactory.

As a method of detecting the vehicle weight, a method of calculating the vehicle weight based on the longitudinal force acting on the vehicle and the acceleration of the vehicle is known, and an example is disclosed in Japanese Patent Laid-Open No. 2001-304948. In the vehicle weight detection device of this publication, the output torque of the engine is obtained using a map in accordance with the engine speed and the fuel injection pump rack position, and the driving force of the vehicle by the engine is calculated. And, while detecting factors related to drag, such as air resistance and rolling resistance acting on the vehicle, for example, vehicle speed, road gradient, etc., the vehicle acceleration is calculated from the vehicle speed differentiation, etc., and the equation of motion (force acting on the vehicle = The vehicle mass or weight is calculated using (vehicle mass × vehicle acceleration).
Japanese Laid-Open Patent Publication No. 2002-39847 discloses a method for obtaining vehicle weight using a motion equation in a vehicle equipped with an automatic transmission having a torque converter. In this publication, a means for calculating the driving torque of the power transmission system from the speed ratio of the input shaft rotation speed and the output shaft rotation speed of the torque converter is used by using the characteristics of the torque converter when calculating the driving force of the vehicle by the engine. Is also disclosed.
JP 2001-241546 A JP 2001-304948 A JP 2002-39847 A

  In recent vehicles in which various vehicle control technologies are adopted to improve the safety during easy driving or traveling of the vehicle, it is an important issue to accurately detect the vehicle weight. At this time, as described above, the vehicle weight detection device that measures the displacement of the spring of the suspension requires a stroke sensor and increases the number of parts.In particular, the measurement result is obtained for a truck that loads a heavy cargo on the loading platform. It may contain errors and is not suitable for accurate vehicle weight detection.

  In the case of calculating the vehicle weight using the equation of motion, it is necessary to accurately calculate the output torque of the engine and various drags for accurate vehicle weight detection. However, the engine output torque fluctuates greatly in a transient state where the fuel supply amount of the engine changes, and the error between the result obtained using the map and the actual output torque may be large. There are difficult aspects.

Even if the driving torque is calculated using the characteristics of the torque converter as in Patent Document 3, the torque converter has a torque amplifying function, so the input torque (engine output torque) and the output torque (mechanical transmission). There is a large difference in input torque. Therefore, it is still difficult to calculate the driving torque of the power transmission system, that is, the output torque of the torque converter with high accuracy. Patent Document 3 describes the output torque from the input speed (engine speed) and speed ratio using the characteristics of the specific input torque of the torque converter (expressed as “capacity coefficient” in Patent Document 3) and the characteristics of the torque ratio. Is also described. However, the characteristic of the specific input torque changes sharply when the output rotational speed is close to the input rotational speed, that is, when the speed ratio is close to 1, and the output torque is obtained by multiplying the specific input torque by the torque ratio. The rate of change with respect to the speed ratio is large. Therefore, in calculating the drive torque using the characteristics of the torque converter, a slight error in the speed ratio results in a large error in the output torque.
In view of such circumstances, the present inventors have intensively studied a vehicle weight detection device in a vehicle provided with a fluid coupling between the engine and the transmission. It has been found that when the driving torque is calculated, it is possible to calculate an accurate driving torque, and the present invention has been completed. In other words, an object of the present invention is to accurately detect the vehicle weight without increasing the number of parts in a vehicle in which a fluid coupling is arranged in the power transmission device.

In order to solve the above problems, the present invention provides a vehicle in which a fluid coupling is disposed in a power transmission device that transmits engine power to driving wheels of a vehicle, and uses the torque characteristics of the fluid coupling, and the input rotation speed and output rotation speed thereof. The driving torque of the vehicle is calculated from the driving torque. That is, the present invention
“A vehicle weight detection device for detecting the weight of a vehicle,
The vehicle includes an engine that drives the vehicle, and a power transmission device that transmits power of the engine to driving wheels.
A fluid coupling is arranged in the power transmission device, a pump of the fluid coupling is connected to an output shaft of an engine, and a turbine of the fluid coupling is connected to the drive wheel,
The vehicle weight detecting device includes a driving force detecting means for detecting a driving force acting on the vehicle, a drag factor detecting means for detecting a factor relating to a drag acting on the vehicle, and an acceleration detecting means for detecting an acceleration of the vehicle. And a weight calculating means for calculating the vehicle weight based on the detected driving force, the factor relating to the drag, and the acceleration, and
The driving force detecting means comprises: a rotational speed detecting means for detecting the rotational speed of the pump of the fluid coupling and the rotational speed of the turbine; and a driving torque calculating means for calculating the driving torque of the vehicle from both rotational speeds ,
The drag factor detecting means detects a road surface gradient θ, which is a factor related to drag, when the vehicle is stopped, and the weight calculating means is a driving force F, a rolling resistance CMgcos θ (C: constant, M: vehicle mass, The vehicle weight Mg is calculated using an equation of motion Mα = F−R established between the drag R including the acceleration g and the acceleration α ”.
This is a vehicle weight detection device. Here, the various “detection” means described above are measured such as those that directly measure and detect the respective amounts, or those that detect vehicle acceleration by differential operation of the measured vehicle speed, for example. It may be obtained from the amount obtained by means such as calculation or map.

  According to a second aspect of the present invention, the weight calculation means includes vehicle speed detection means for detecting the vehicle speed of the vehicle and vehicle speed restriction means for prohibiting calculation of the vehicle weight when the vehicle speed exceeds a predetermined vehicle speed. It is preferable.

  According to a third aspect of the present invention, the weight calculation means can be provided with an integral calculation means for integrating the detected driving force, the factor relating to the drag, and the detected value of the acceleration within a predetermined range.

According to a fourth aspect of the present invention, the weight calculating means is provided with a driving torque limiting means for prohibiting the calculation of the vehicle weight when the driving torque calculated by the driving torque calculating means is equal to or less than a predetermined torque. Is preferred.

In a vehicle that is an object of the present invention, a fluid coupling is disposed in a power transmission device, such as between an engine and a transmission, and engine power is transmitted to drive wheels of the vehicle via this. When the vehicle starts, the pump of the fluid coupling and the turbine rotate independently, and the rotational speed of the turbine connected to the input shaft of the transmission is higher than the rotational speed of the pump connected to the output shaft of the engine. There is a small slip between the pump and the turbine. The torque transmission amount Tf of the fluid coupling is determined by the rotational speed of the pump and the speed ratio e (ratio of the rotational speed of the turbine to the rotational speed of the pump). This characteristic is known as a coefficient τ representing the specific input torque (or a capacity coefficient K which is the reciprocal of the square root thereof), and is uniquely determined according to each fluid coupling, as shown in FIG. Furthermore, it has a characteristic that increases as the speed ratio e decreases. The torque transmission amount Tf of the fluid coupling is obtained from the specific input torque coefficient τ by the following equation.
Tf = τ × (pump speed) ²
Therefore, by measuring the pump rotation speed and the speed ratio e, it is possible to determine the torque transmission amount of the fluid coupling, that is, the driving torque transmitted to the drive wheels of the vehicle. The driving force of the vehicle necessary for calculating the vehicle weight can be calculated based on factors such as the ratio and the effective diameter of the wheels. The calculation of the driving force using the characteristics of the fluid coupling directly calculates the transmission torque of the vehicle drive system. Therefore, the driving force of the vehicle is compared with the calculation method of obtaining the engine output torque from parameters such as the fuel supply amount of the engine. Force can be calculated accurately.

  Incidentally, Patent Document 3 describes a method of calculating a driving torque as an output torque of a torque converter using characteristics of the torque converter. However, the torque converter has a torque amplification function, and the output torque is obtained by multiplying the specific input torque τ by the torque ratio t, and the rate of change with respect to the speed ratio e is large as shown in FIG. Therefore, if there is an error in the measurement of the speed ratio e, the calculation error of the driving torque is also amplified, and it is difficult to calculate the driving torque with high accuracy. The characteristic of the specific input torque τ of the torque converter is the speed ratio e. Is steep in the joint range portion close to 1, and the output torque cannot be calculated depending on the vehicle speed. On the other hand, in the fluid coupling used in the present invention, the turbine torque on the output side is always equal to the pump torque on the input side and there is no torque amplification effect. Therefore, the calculation of the transmission torque Tf (drive torque) is highly accurate. Is possible. Furthermore, in the fluid coupling, since the rate of change of the specific input torque is relatively small even at a portion where the speed ratio e is close to 1, accurate calculation can be performed over a wide range of vehicle speeds of the vehicle.

According to a second aspect of the present invention, when the vehicle speed calculation means is provided in the weight calculation means, the calculation of the vehicle weight is prohibited when the vehicle speed exceeds a predetermined vehicle speed, The transmission torque is calculated at a portion where the characteristic with respect to the speed ratio e of the joint is stable, and the accuracy is further improved. In addition, when the vehicle speed is low, the air resistance acting on the vehicle becomes a small amount, and the calculation error of the drag acting on the vehicle can be reduced.
As in the invention of claim 3, when the weight calculation means is provided with integral calculation means for integrating the detected value of the driving force, the drag, and the detected value of the acceleration in a predetermined range, each detected value is an average. Since the error included in each detected value is canceled out, the reliability of the calculation result is improved from this aspect.

In addition, when the driving torque is calculated using the characteristics of the fluid coupling, if the calculated transmission torque of the fluid coupling is small, the calculation is performed at a portion where the characteristic change is large, and the error is relatively small. growing. According to the fourth aspect of the present invention, when the driving torque limiting means is provided in the weight calculating means, and the calculation of the vehicle weight is prohibited when the driving torque calculated by the driving torque calculating means is equal to or less than the predetermined torque, the calculation of the vehicle weight is performed. Accuracy can be improved.

  Hereinafter, a vehicle weight detection device of the present invention will be described based on the drawings. FIG. 1 shows a schematic diagram of a power transmission device in a vehicle in which a fluid coupling is disposed between an engine and a transmission, which is an object of the present invention, and FIG. 2 is an enlarged view in the vicinity of the fluid coupling. Show. The engine of this embodiment is a diesel engine and has a relatively large output torque at low speed. When this is combined with a fluid coupling, a sufficient driving torque can be obtained when the vehicle starts even if the fluid coupling does not have a torque increasing function. It is generated and smooth start is possible.

  1 and 2, a fluid coupling 2 is disposed behind the diesel engine 1, and a transmission 4 is connected via a wet multi-plate clutch 3. A number of friction plates are placed between the input shaft 31 and the output shaft 32 of the wet multi-plate clutch 3, the input shaft 31 is the output shaft 24 of the fluid coupling 2, and the output shaft 32 is the input shaft 41 of the transmission 4. Are respectively spline-fitted. The wet multi-plate clutch 3 is disengaged when the gear position of the transmission 4 is switched, and is maintained in the engaged state except during gear shifting. Therefore, the output shaft 24 of the fluid coupling 2 is input to the transmission 4. The shaft 41 is directly connected to the shaft 41. The transmission 4 is a normal parallel shaft gear mechanism type transmission in which a transmission sleeve is meshed with a gear spline (dog teeth) integrally formed with a gear, and includes a known synchronization mechanism including a synchronizer ring or the like. In the transmission 4, a shift is performed by the shift actuator 43 in accordance with a shift command from the vehicle electronic control device 6, and an optimum shift stage is selected according to the traveling state of the vehicle. The shift stage can be switched manually by a shift lever operated by the driver. The output shaft 42 of the transmission 4 is coupled to the propeller shaft, and drives the drive wheels of the vehicle via the final gear 5.

The fluid coupling 2 includes a pump 21 and a turbine 22 housed in a casing 23 (FIG. 2) of the fluid coupling. Since the casing 23 is fixed to the output shaft of the diesel engine 1 and the fluid coupling pump 21 is integrally coupled to the casing 23, the pump 21 is connected to and integrated with the output shaft of the diesel engine 1. Rotate. Further, since the turbine 22 is spline-fitted with the output shaft 24 of the fluid coupling, and the output shaft 24 is spline-fitted integrally with the input shaft 31 of the wet multi-plate clutch 3, the wet multi-plate clutch 3 is When fastened, the fluid coupling turbine 22 is directly connected to the input shaft 41 of the transmission 4.
Further, the fluid coupling 2 includes a lockup clutch mechanism for fastening the pump 21 and the turbine 22, and the lockup clutch mechanism includes a clutch plate 25 fitted in the turbine 22 and a friction lining 26 fixed to the clutch plate 25. Consists of When the vehicle speed exceeds a predetermined value after the vehicle has started, the oil pressure acting on the clutch plate 25 is controlled so that the friction lining 26 is brought into close contact with the casing 23, and the turbine 22 and the pump 21 are directly connected to each other. Avoid power loss due to slipping.

  When the vehicle is running at a low speed, such as when the vehicle starts, the lockup clutch mechanism is disconnected, and the pump 21 integrated with the output shaft of the diesel engine 1 rotates independently of the turbine 22 connected to the drive wheels of the vehicle. The vehicle starts smoothly by sliding between the pump 21 and the turbine 22. At this time, the rotational speed of the pump 21 is lower than the rotational speed of the turbine 22, and the speed ratio e, which is the ratio of the turbine rotational speed to the pump rotational speed, is 1 or less. The transmission torque Tf between the two is determined from the characteristic of the specific input torque τ of the fluid coupling shown in FIG. 5 based on the rotational speed of the pump 21 and the speed ratio e. The vehicle weight detection device of the present invention calculates the driving force acting on the vehicle based on the transmission torque Tf at this time.

  Here, the vehicle weight detection device 61 of the present invention incorporated in the vehicle electronic control device 6 will be described. Since the vehicle weight detection device 61 calculates and detects the vehicle weight using an equation of motion, the vehicle weight detection device 61 detects a driving force F acting on the vehicle, a factor relating to a drag force R acting on the vehicle, and a vehicle acceleration α. There is a need. As shown in FIG. 3, the vehicle weight detection device 61 includes a driving force detection unit, a drag factor detection unit, and an acceleration detection unit, which processes signals input to each to detect a driving force and the like. Further, the vehicle weight detection device 61 includes weight calculation means for calculating the vehicle weight based on the detected driving force F, the factor relating to the drag force R, and the acceleration α, and the calculated vehicle weight is stored in the vehicle electronic control device 61. Used for various controls.

The calculation procedure in the vehicle weight detection device 61 of the present invention is shown in the flowchart of FIG.
When the calculation of the vehicle weight is instructed, first, the vehicle speed at that time is detected to determine whether or not the vehicle speed is equal to or less than a predetermined value (S1). If the vehicle speed is less than or equal to the predetermined value, the process proceeds to the next step and the calculation is started. However, if the vehicle speed exceeds the predetermined value, the calculation is prohibited. This is because when the vehicle speed exceeds a predetermined value, the speed ratio e is close to 1, and there is a possibility that an error when detecting the driving force F acting on the vehicle becomes large, and the calculation error of the air resistance also increases. This is to prevent the reliability of the calculated value of the vehicle weight from being lowered.

The driving force F acting on the vehicle is calculated using the transmission torque Tf of the fluid coupling 2. Since the output shaft 24 of the fluid coupling is directly connected to the input shaft of the transmission 4 except during gear shifting, the output torque of the fluid coupling 2, that is, the transmission torque Tf is driven by the vehicle during low speed traveling such as when the vehicle starts. Torque. As shown in FIG. 1, rotation speed sensors 62 and 63 are attached to the vehicle power transmission device, and the vehicle weight detection device 61 has a rotation speed np (diesel engine) of the pump 21 measured by the rotation speed sensor 62. 1) and the signal of the rotational speed nt of the turbine 22 (input shaft rotational speed of the wet multi-plate clutch 3) measured by the rotational speed sensor 63 are input (S2, S3), and in step S4 A speed ratio e is calculated. Further, a characteristic diagram corresponding to FIG. 5 representing the characteristic of the specific input torque τ of the fluid coupling 2 is stored as a map in the storage unit of the driving force detecting means. Thus, the driving force detecting means obtains the transmission torque of the fluid coupling 2 by using the above-described calculation formula of Tf (S5, S6), and further, the gear ratio Gt of the gear stage at that time of the transmission 4 and the final gear 5 The driving force F exerted on the road surface by the driving wheels of the vehicle is calculated as follows from the respective factors of the gear ratio Gf and the tire moving radius Dr of the driving wheels (S7).
F = Tf × Gt × Gf / Dr
By the way, when the value of the transmission torque Tf obtained in S6 is small and falls below the predetermined torque value, the characteristic of the transmission torque deviates from a stable region and the error relatively increases. A step of comparing the transmission torque Tf calculated after S6 with a predetermined torque value is added, and a detection value of the driving force F is provided by providing a driving torque limiting means for prohibiting the calculation of the vehicle weight when the torque falls below the predetermined torque value. Reliability can be improved.

The drag R acting on the vehicle can be divided into a rolling resistance Rr, an air resistance Rf, and a gradient resistance Ri. Of these, the air resistance Rf is a drag not related to the vehicle weight, and is proportional to the square of the front projection area A and the vehicle speed V of the vehicle, and is expressed by the following equation.
Rf = C ₁ × A × V ² : C ₁ is a constant related to the coefficient of air friction The air resistance Rf is a very small value when the vehicle speed is very low, such as when the vehicle starts, and even if there is a detection error, the vehicle The influence on the calculation of the weight is very small.

On the other hand, the rolling resistance Rr and the gradient resistance Ri are functions of the vehicle weight. If the gradient of the road surface on which the vehicle travels is θ, the mass of the vehicle is M, and the gravitational acceleration is g, the rolling resistance Rr and the gradient resistance Ri can be expressed by the following equations, respectively.
Rr = C ₂ × Mgcos θ: C ₂ is a constant related to the rolling friction coefficient Ri = Mg sin θ

This vehicle is equipped with a vehicle speed sensor for detecting the vehicle speed and an acceleration sensor for detecting the acceleration. The acceleration α of the vehicle is calculated by differentiating the vehicle speed detected by the vehicle speed sensor (S8). Also, the acceleration sensor detects the acceleration added with the value of gsin θ that is an acceleration component accompanying the gradient. The road surface gradient θ can be calculated by comparing the acceleration α obtained by differentiating the vehicle speed detected by the vehicle speed sensor with the acceleration detected by the acceleration sensor. When the vehicle is stopped, the value of the acceleration sensor is only gsin θ. Even in this case, the gradient θ can be detected, and if it is detected while the vehicle is stopped, an error caused by the vibration of the vehicle can be avoided.
The storage unit of the drag factor detection means stores data such as the constants C _{1 and} C _{2 and} the front projection area A of the vehicle necessary for drag calculation. The drag factor detection means includes a vehicle speed sensor and A factor θ related to rolling resistance is calculated from the acceleration sensor, and further, other factors related to air resistance and rolling resistance are also calculated using these data (S9).

In the weight calculation means of the vehicle weight detection device 61, calculation of the vehicle weight is executed based on the detection values calculated by these detection means (S10). First, the equation of motion of the vehicle is expressed by the following equation.
Mα = F−R = F− (C ₁ AV ² + C ₂ Mgcos θ + Mgsin θ)
From this equation, the mass M of the vehicle can be calculated as follows, and the vehicle weight can be detected by multiplying the obtained value of M by the gravitational acceleration g.
M = (F−C ₁ AV ² ) / (α + C ₂ gcos θ + gsin θ)

In the above calculation procedure, calculation is performed using the detected value at the time of detection of driving force etc. as it is, but integration means is provided in the calculation process, and each detection value is integrated by a predetermined range to perform calculation. May be executed. Providing the integrating means improves the calculation accuracy of the vehicle weight as a result of averaging the detected values.
The vehicle weight obtained by the vehicle weight detection device 61 is used to optimize various controls executed in the vehicle electronic control device 6. For example, by switching the gear position of the transmission 4 by the speed change actuator 43 in consideration of not only the running state of the vehicle but also the vehicle weight parameter, even in a vehicle such as a truck that has a great change in vehicle weight, An appropriate gear position is selected. In addition, in a vehicle that performs roll control or the like for improving running stability, it is possible to optimize the control mode by changing the control factor or the like according to the vehicle weight parameter.

  As described above in detail, the present invention calculates the driving torque of the power transmission system using the characteristics of the fluid coupling and detects the vehicle weight from the equation of motion when detecting the vehicle weight in the vehicle in which the fluid coupling is arranged in the power transmission device. Is calculated. Therefore, the present invention is applicable not only to a vehicle equipped with a diesel engine as in the above-described embodiment, but also to a vehicle equipped with a gasoline engine. In addition, when calculating the vehicle weight, various changes can be made to the embodiment, such as executing the calculation based on the equation of motion taking into account the influence of the rotational inertia weight of the power transmission device as necessary. Obviously it is possible.

It is the schematic of the power transmission device for vehicles to which the weight detection apparatus of this invention is applied. It is detail drawing which shows the fluid coupling of the power transmission device for vehicles. It is a figure which shows the structure of the weight detection apparatus of this invention. It is a flowchart which shows the calculation procedure of the weight detection apparatus of this invention. It is a figure which shows the characteristic of the transmission torque and speed ratio of a fluid coupling. It is a figure which shows the characteristic of the torque and speed ratio of a torque converter.

Explanation of symbols

1 Diesel engine 2 Fluid coupling (fluid coupling)
21 Pump 22 Turbine 25 Clutch plate 26 Friction lining 3 Wet multi-plate clutch 4 Transmission 43 Shift actuator 5 Final gear 6 Vehicle electronic control device 61 Vehicle weight detection device 62 Rotation speed sensor
63 Speed sensor (for turbine speed detection)

Claims (4)

A vehicle weight detection device for detecting the weight of a vehicle,
The vehicle includes an engine that drives the vehicle, and a power transmission device that transmits power of the engine to driving wheels.
A fluid coupling is arranged in the power transmission device, a pump of the fluid coupling is connected to an output shaft of an engine, and a turbine of the fluid coupling is connected to the drive wheel,
The vehicle weight detecting device includes a driving force detecting means for detecting a driving force acting on the vehicle, a drag factor detecting means for detecting a factor relating to a drag acting on the vehicle, and an acceleration detecting means for detecting an acceleration of the vehicle. And a weight calculating means for calculating the vehicle weight based on the detected driving force, the factor relating to the drag, and the acceleration, and
The driving force detecting means comprises: a rotational speed detecting means for detecting the rotational speed of the pump of the fluid coupling and the rotational speed of the turbine; and a driving torque calculating means for calculating the driving torque of the vehicle from both rotational speeds ,
The drag factor detecting means detects a road surface gradient θ, which is a factor related to drag, when the vehicle is stopped, and the weight calculating means is a driving force F, a rolling resistance CMgcos θ (C: constant, M: vehicle mass, A vehicle weight detection apparatus that calculates a vehicle weight Mg using an equation of motion Mα = F−R that is established between a drag force R including acceleration g and acceleration α . 2. The vehicle weight detection device according to claim 1, wherein the weight calculation means includes vehicle speed detection means for detecting a vehicle speed of the vehicle, and vehicle speed limit means for prohibiting calculation of the vehicle weight when the vehicle speed exceeds a predetermined vehicle speed. . 3. The vehicle weight detection device according to claim 1, wherein the weight calculation unit includes an integration calculation unit that integrates a detected value of a driving force and a drag and a detected value of acceleration within a predetermined range. It said weight computing means according to any one of claims 1 to 3 having a drive torque limiting means for inhibiting operation of the vehicle weight when driving torque, which is calculated by the drive torque calculating means is equal to or less than a predetermined torque Vehicle weight detection device.

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