JP2001304948A - Vehicle weight detection device - Google Patents

Abstract

(57) [Problem] To provide a vehicle weight detection device that can always accurately calculate the vehicle weight regardless of the running state of the vehicle, and can realize accurate control based on the calculation result. SOLUTION: A gravitational acceleration g, a driving force F of a vehicle generated by an engine torque, an air resistance Rl acting on the vehicle,
Set the following equation to calculate the vehicle weight W from the inertial weight Wr of the rotating part of the power transmission system of the vehicle, the actual acceleration αv of the vehicle obtained from the vehicle speed, the road gradient sinθ where the vehicle is running, and the tire rolling resistance coefficient μ. Then, When the absolute value of the denominator of this equation is equal to or greater than a predetermined value (the determination in step S4 is YES) and the degree of influence of the error included in the actual acceleration αv on the denominator is small, the vehicle weight W calculation process is executed ( Step S6).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle weight detecting device for detecting the weight of a running vehicle.

[0002]

2. Related Background Art In recent years, a vehicle weight detecting device for detecting a vehicle weight based on driving force, acceleration, and the like of a running vehicle has been proposed. This type of detection device is mounted, for example, on a truck or the like in which the weight of a vehicle fluctuates greatly depending on the load state, and the detection result is reflected in the control of the engine and the automatic transmission to optimize the control.

[0003] The vehicle weight is calculated by the following equation (1) in which known motion equations of the vehicle are arranged by the vehicle weight.

[0004]

(Equation 1)

Here, g is the gravitational acceleration, F is the driving force of the vehicle generated by the engine torque, Rl is the air resistance acting on the vehicle, Wr is the inertial weight of the rotating part of the vehicle power transmission system, and αv is the vehicle speed. The actual acceleration of the vehicle obtained from
θ is the gradient of the road on which the vehicle is traveling, and μ is the rolling resistance coefficient of the tire. That is, the numerator in equation (1) is the driving force F
Represents the propulsion force acting on the vehicle in consideration of the air resistance Rl and the inertial weight Wr of the rotating part, and the denominator represents the vehicle acceleration in consideration of the road gradient sinθ and the rolling resistance μ obtained by the propulsion force. When the vehicle acceleration is small relative to the force, the vehicle weight W is calculated to be a large value. Conversely, when the vehicle acceleration is large to the propulsive force, the vehicle weight W is calculated to be a small value.

[0006]

In the above equation (1),
For example, the numerator and the denominator are both large during full acceleration with the accelerator fully open, and the numerator and denominator are both small during gentle acceleration with a small accelerator opening, but the same vehicle in any case unless the actual vehicle weight W changes. The weight W should be calculated. However, the parameters used in equation (1) include an error, and the error may have a significant effect on the calculation result depending on the traveling state, and the vehicle weight W may be calculated far apart from the actual. Therefore, there has been a problem that inappropriate control is performed based on such incorrect vehicle weight W.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle weight detecting device capable of always accurately calculating the vehicle weight irrespective of the running state of the vehicle, and thereby realizing accurate control based on the calculation result. It is in.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a gravitational acceleration g, a driving force F of a vehicle generated by an engine torque, an air resistance Rl acting on the vehicle, a power transmission of the vehicle. A vehicle propulsion force calculating means for calculating a vehicle propulsion force {g (F-R1) -Wr · αv} based on an inertial weight Wr of a rotating part of the system and an actual acceleration αv of the vehicle obtained from a vehicle speed; Vehicle acceleration calculating means for calculating a vehicle acceleration (αv + g · sinθ + g · μ) including a gradient component based on the actual acceleration αv, the gravitational acceleration g, the road gradient sinθ at which the vehicle is traveling, and the tire rolling resistance coefficient μ; The propulsion force {g (F−R1) −Wr · αv} of the vehicle calculated by the propulsion force calculation means and the vehicle acceleration (αv +
g · sin θ + g · μ) and vehicle acceleration (αv + g · sin θ + g ·) including the gradient component calculated by the vehicle acceleration calculation means.
calculation permission means for permitting the vehicle weight calculation means to execute the calculation processing when μ) is equal to or greater than a predetermined value.

Therefore, the vehicle acceleration including the gradient component (αv
+ G · sin θ + g · μ) is equal to or greater than a predetermined value, and when the calculation permission means makes a permission determination, the vehicle weight calculation processing by the vehicle weight calculation means is executed. Vehicle acceleration (αv + g · s
The actual acceleration αv applied to the calculation of (in θ + g · μ) includes a relatively large error because it is obtained by differentiating the vehicle speed, but the vehicle acceleration (αv + g · sin θ + g · μ)
Is larger, the degree of influence of the error of the actual acceleration αv becomes smaller. Therefore, the vehicle acceleration (αv + g · sinθ + g ·
If the calculation process is executed when μ) is equal to or larger than the predetermined value, the vehicle weight can be calculated with high accuracy without being significantly affected by the error included in the actual acceleration αv.

[0010] In the invention according to the second aspect, there is provided a determining means for determining that the vehicle is in a state in which the load capacity can be changed,
The vehicle weight calculating means performs an integrated average of the calculated vehicle weights, and resets past calculation results when the determining means determines that the load capacity can be changed. Therefore, the calculation accuracy of the vehicle weight is improved by the integrated average, and when it is estimated that the vehicle weight has changed together with the load amount based on the determination of the determination means, the past calculation result is reset to an inappropriate calculation result. The integrated averaging based is prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a vehicle weight detecting device mounted on a large truck will be described below. FIG. 1 is an overall configuration diagram showing a vehicle weight detection device according to an embodiment. As shown in this figure, a vehicle is equipped with a diesel engine 1, and the rotation of the engine 1 is transmitted to drive wheels 3 via a differential gear (not shown) after being shifted by a transmission 2. I have. The transmission 2 is configured as a mechanical transmission without a torque converter, and the speed change operation and the clutch connection / disconnection operation are automatically performed by an actuator (not shown).

An input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) for storing control programs and control maps, and a central processing unit (C)
An electronic control unit (ECU) 11 having a PU, a timer counter, and the like is provided. An engine rotation speed sensor 12 for detecting a rotation speed Ne of the diesel engine 1 is provided on an input side of the ECU 11, and a control rack position R of a fuel injection pump 1a provided in the diesel engine 1 is provided.
rack position detection sensor 13 for detecting w, automatic transmission 2
Gear position sensor 14 for detecting the gear position it of the vehicle speed V
, A G sensor 16 for detecting front and rear G acting on the vehicle, and the like. ECU1
The output side of 1 is connected to a fuel injection pump 1a of the engine 1, an actuator for performing a shift operation of the automatic transmission 2 and a clutch connection / disconnection operation, and the like.

The ECU 11 controls the fuel injection amount and the injection timing of the fuel injection pump 1a based on information from each sensor to operate the engine 1, and determines a target gear position according to the running state of the vehicle. A speed change operation and a clutch connection / disconnection operation are executed by the actuator to achieve the target shift speed. Also, while the vehicle is running, the ECU 11 calculates the vehicle weight W based on information from each sensor, and reflects the detection result in the control of the engine 1 and the automatic transmission 2 to optimize the control. .

Hereinafter, the calculation processing of the vehicle weight W executed by the ECU 11 will be described in detail. FIG. 2 shows a vehicle weight calculation routine executed by the ECU. The ECU 11 executes the routine of FIG. 2 at a predetermined control interval, and first determines in step S2 whether the vehicle weight W can be calculated. In the vehicle weight detection device of the present embodiment, the actual calculation process is performed based on the above equation (1), as in the conventional example. It is necessary to be able to compare the propulsion force of the vehicle with the vehicle acceleration on the denominator side. Further, even during traveling, for example, at the time of a foot brake operation in which the braking force acts as a disturbance to the driving force (in the equation, Situation),
Alternatively, the vehicle weight W cannot be calculated when the vehicle is running at the second speed in which the engine torque Te used for calculating the driving force F of the vehicle cannot be accurately estimated during a shift in which the driving force becomes 0 due to the clutch disengagement. Therefore, when the vehicle is in these states, a NO (negative) determination is made in step S2, and the routine ends.

When the vehicle is not in the above-mentioned situation, a YES (Yes) determination is made in step S2, and the process proceeds to step S4. In step S4, it is determined whether or not the absolute value of the denominator of equation (1) is equal to or greater than a predetermined value (calculation permitting means).
If the answer is O, the routine ends. If the determination in step S4 is YES, the process proceeds to step S6, where the expression (1)
The vehicle weight W is calculated based on the vehicle weight W (vehicle propulsion force calculating means, vehicle acceleration calculating means, vehicle weight calculating means). In the present embodiment, 0.6 is set as the predetermined value for determining the absolute value of the denominator, but the value is arbitrarily changed according to the specifications of the engine 1 and the automatic transmission 2 of the vehicle. It is possible.

Thereafter, in step S8, it is determined whether a reset condition is satisfied (determination means). This reset condition is satisfied when it becomes possible to unload the cargo.Specifically, when the ignition key is turned off, the parking brake is operated, and the vehicle is stopped for a predetermined time or longer, the vehicle is considered to have reached the above-described condition and reset. The satisfaction of the condition is determined. When the determination in step S8 is NO, the vehicle weight W calculated in step S10 is integrated and averaged with respect to the past calculation result, and then the routine ends.

If the determination in step S8 is YES, in step S12, the past calculation result used in step S10 is reset. That is, in this case, the vehicle weight W changes due to the unloading of the load, and the past calculation result does not correspond to the current vehicle weight W. Then, the thus calculated vehicle weight W (integrated average value) is applied to control of the engine 1 and the automatic transmission 2.

The calculation procedure of the vehicle weight W executed in step S6 will be described. As shown in FIG. 3, the engine rotation speed Ne detected by the engine rotation speed sensor 12 and the rack position detection sensor 13 The current engine torque Te is estimated from a preset engine torque map based on the rack position Rw of the fuel injection pump 1a detected at the step (1), and the engine torque Te is detected by the gear position detection sensor 14. The transmission gear ratio obtained from the determined gear position it, and the correction based on the differential gear ratio, the moving radius of the tire, and the like that are known in advance are added, and the driving force F of the vehicle in Equation (1) is calculated. In addition, the inertia weight Wr of the rotating part of the power transmission system is preset as a constant for each transmission gear ratio at each gear position it, and the inertia weight Wr applied to the equation (1) is selected according to the gear position it. Is done.

On the other hand, the vehicle acceleration αv is calculated by differentiating the vehicle speed V detected by the vehicle speed sensor 15,
The road surface gradient sin θ is calculated based on the vehicle acceleration αv and the front and rear G detected by the G sensor 16. Vehicle speed V
Is also used to calculate the air resistance R1 acting on the vehicle, and based on the air resistance coefficient and the total projected area previously obtained from the shape of the vehicle, the air resistance R based on the current vehicle speed V
1 is calculated. The rolling resistance coefficient μ and the gravitational acceleration g of the tire are set in advance as constants.

Then, the parameters described above are substituted into the equation (1) in step S6 to determine the vehicle weight W. This calculation is performed by the vehicle acceleration αv, the gravitational acceleration g,
This process is executed only when the absolute value of the denominator of the equation (1) calculated from the road surface gradient sin θ and the tire rolling resistance μ is equal to or larger than a predetermined value and a determination of YES is made in step S4. FIG. 4 shows the state of the vehicle weight W calculation process by the ECU 11 described above.
It will be described according to the time chart of FIG. Note that this time chart shows a case where the vehicle starts and accelerates with the accelerator fully opened on a flat road, and the net vehicle weight W is 11300 kg.

Since the heavy-duty truck according to the present embodiment starts in the second speed, the vehicle starts in the second speed by connecting the clutch.
As the vehicle speed V increases, the gears are sequentially shifted to the third, fourth, and fifth speeds. At the time of the second speed running at the start of the start, NO is determined in step S2 due to the estimation accuracy of the engine torque Te as described above.
Is determined, the calculation processing of the vehicle weight W is not executed, and even in the section Ts during the shift to the third speed,
Since a determination of NO is made in step S2 because the driving force F becomes 0, the calculation process is not performed. Further, as is well known, the acceleration αv of the vehicle becomes small during the shift and does not rise sharply after the shift is completed. Therefore, the section Ta immediately after the shift
Here, the absolute value of the denominator of the equation (1) becomes smaller than the predetermined value because the acceleration αv becomes transiently small, and the calculation process is not performed because the determination of NO is made in step S4. Although the figure shows the case where W is calculated in the section Ta for reference, the calculated value is far from the actual vehicle weight of 11300 kg.

When the vehicle starts running at the third speed and the acceleration αv rises, the absolute value of the denominator becomes equal to or greater than a predetermined value, so that the determination in step S4 becomes YES and the calculation process is started, and this calculation process is continued. The operation is continued until the shift to the fourth speed starts. Therefore, the vehicle weight W is sequentially calculated by the formula (1) as shown by the thin line in the figure, and is integrated and averaged by the thick line. After that, the above processing is repeated, and the calculation process is stopped in the section Ts during each shift and the section Ta immediately after the shift, and the calculation processing is executed in other sections.

As described above, in the vehicle weight detecting apparatus according to the present embodiment, the calculation processing is executed or stopped according to the magnitude of the absolute value of the denominator of the equation (1). This is based on the following findings. As described with reference to FIG.
Although v is obtained from the vehicle speed V, the vehicle acceleration αv includes a relatively large error due to the differential processing executed at that time. As is apparent from the equation (1), the vehicle weight W is calculated by dividing the numerator by the denominator to a large value of, for example, about 11300 kg. Therefore, the denominator is inevitably a much smaller value than the numerator. Take. The vehicle acceleration αv is applied not only to the denominator but also to the numerator. However, the vehicle acceleration αv has a particularly large influence on the small denominator, and the error included in the vehicle acceleration αv has a large influence. Therefore, when the absolute value of the denominator is less than the predetermined value, the error of the vehicle acceleration αv has a large effect and the vehicle weight W cannot be calculated accurately. The calculation process is executed only when is small.

In the above-described example, the running state in which the vehicle weight W is calculated when the absolute value of the denominator is equal to or more than the predetermined value is the time of acceleration on a flat road where the acceleration αv is large. The same applies when traveling at a constant speed on an uphill road or when accelerating on an uphill road.When traveling at a constant speed on an uphill road, the road gradient sinθ becomes large. In both cases, the absolute value of the denominator becomes equal to or greater than the predetermined value, and the calculation process is executed.

The above description is directed to the case where the engine 1 applies a positive propulsive force to the vehicle, but the case where the engine 1 applies a negative propulsive force (braking force) such as when an engine brake or an exhaust brake is used. The same applies to (the braking by the foot brake is excluded as described above). Therefore, when the vehicle is decelerated on a flat road, the acceleration αv is large on the negative side, and when traveling at a constant speed on a downhill, the road gradient sinθ is large on the negative side. Since both the vehicle acceleration αv and the vehicle acceleration αv are large on the negative side, the absolute value of the denominator becomes equal to or larger than a predetermined value in any case, and the calculation process is executed.

On the other hand, in the above-described example, the running state in which the calculation process is stopped when the absolute value of the denominator is less than the predetermined value is immediately after the shift during acceleration when the acceleration αv becomes transiently small. The same applies to the case of traveling at a constant speed. In this case, since the road gradient sin θ and the vehicle acceleration αv both become 0, the absolute value of the denominator becomes less than the predetermined value, and the calculation process is stopped.

As described above, in the vehicle weight detecting apparatus according to the present embodiment, focusing on the fact that the calculation accuracy changes in accordance with the size of the denominator of the equation (1) for calculating the vehicle weight W, the absolute value of the denominator is calculated. The calculation process is executed only when the influence of the error included in the vehicle acceleration αv on the denominator is smaller than a predetermined value. Therefore, when the degree of the influence of the error of the vehicle acceleration αv is large, the calculation process of the vehicle weight W is stopped, and the situation where the vehicle weight W (for example, the section Ta in FIG. 4) that is far from the actual one is calculated is prevented. Therefore, the vehicle weight W can always be accurately calculated regardless of the running state of the vehicle, and the engine 1 and the automatic transmission 2 can be accurately controlled based on the calculation result.

Since the denominator of the equation (1) takes into account not only the vehicle acceleration αv but also the road surface gradient sinθ, the engine 1 exerts the propulsive force as in the case of the above-mentioned constant speed running on an uphill road. Even though the vehicle weight W can be calculated, the calculation process is executed because the road gradient sinθ is large even in the traveling state where the calculation is stopped in the determination of only the vehicle acceleration αv, and the frequency of the calculation process is increased. Therefore, the calculation accuracy can be improved.

On the other hand, since the vehicle weight W is integrated and averaged using the past calculation results, the calculation accuracy can be further improved, and the reset condition is satisfied and the vehicle weight W changes due to the unloading of the load. When it is inferred that
Since the past calculation result is reset, erroneous calculation of the vehicle weight W based on the integrated average based on the inappropriate calculation result can be prevented.

Although the embodiment has been described above, aspects of the present invention are not limited to this embodiment. For example, in the above embodiment, the present invention is embodied as a vehicle weight detecting device mounted on a large truck, but the type of the vehicle is not limited. For example, the present invention may be embodied as a vehicle weight detecting device mounted on a bus vehicle.

[0031]

As described above, according to the vehicle weight detecting device of the first aspect of the present invention, when the vehicle acceleration (αv + g · sinθ + g · μ) including the gradient component is equal to or more than the predetermined value, the error included in the actual acceleration αv The vehicle weight calculation process is executed when the degree of influence is small, so that the vehicle weight can be calculated with high accuracy, and the engine and the automatic transmission can be accurately controlled based on the calculation result. .

According to the vehicle weight detecting device of the second aspect of the present invention, the calculation accuracy of the vehicle weight can be further improved by the integrated averaging, and the vehicle weight changes along with the loaded amount based on the judgment by the judging means. When it is inferred, it is possible to prevent the erroneous calculation of the vehicle weight by the integrated average based on the inappropriate calculation result by resetting the past calculation result.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a vehicle weight detection device according to an embodiment.

FIG. 2 is a flowchart illustrating a vehicle weight calculation routine executed by an ECU.

FIG. 3 is an explanatory diagram showing a procedure for calculating a vehicle weight.

FIG. 4 is a time chart illustrating a situation of a vehicle weight calculation process.

[Explanation of symbols]

g Gravitational acceleration F Driving force Rl Air resistance Wr Inertial weight αv Actual acceleration sinθ Road gradient μ Rolling resistance coefficient Te Engine torque W Vehicle weight 11 ECU (vehicle propulsion force calculation means, vehicle acceleration calculation means, vehicle weight calculation means, calculation permission means , Determination means)

Claims (2)

[Claims] 1. A gravitational acceleration g, a driving force F of a vehicle generated by an engine torque, an air resistance Rl acting on the vehicle,
Vehicle propulsion force calculating means for calculating the vehicle propulsion force {g (F-R1) -Wr · αv} based on the inertial weight Wr of the rotating part of the vehicle power transmission system and the actual acceleration αv of the vehicle obtained from the vehicle speed And the actual acceleration αv of the vehicle, the gravitational acceleration g, the road gradient sinθ on which the vehicle is traveling, and the rolling resistance coefficient μ of the tire.
Based on the vehicle acceleration (αv + g · sinθ) including the gradient component
+ G · μ), the vehicle propulsion {g (F−R1) −Wr · αv} calculated by the vehicle propulsion calculation unit, and the vehicle acceleration calculation unit Vehicle acceleration (αv
+ G · sin θ + g · μ), and a vehicle weight (αv + g · sin θ + g · μ) including a gradient component calculated by the vehicle acceleration calculator is equal to or more than a predetermined value. And a calculation permitting means for permitting the vehicle weight calculating means to execute the calculating process. 2. A vehicle control system comprising: a determination unit configured to determine that the vehicle is in a state in which the load amount can be changed; wherein the vehicle weight calculation unit averages the calculated vehicle weight and calculates the load amount by the determination unit. 2. The vehicle weight detecting device according to claim 1, wherein when it is determined that the condition is changeable, the past calculation result is reset.