JPH0584834U - Vehicle weight detection device - Google Patents

Abstract

(57) [Abstract] [Purpose] The objective is to detect the vehicle weight regardless of whether the vehicle is loaded or emptied, and to use the existing sensor only without providing a weight sensor while traveling. [Structure] Accelerator opening, engine rotation at minute time intervals,
The vehicle speed is read, and the engine torque and acceleration / deceleration are calculated from each detection signal (S1 to S3). Since the running resistance and the wheel driving force are balanced when the acceleration / deceleration changes, the current vehicle weight W _n is calculated based on the calculation formula of low running resistance,
Calculate the moving average value of the previous average value and the current value,
The calculated value W is output as the detected vehicle weight value (S
4-S7).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vehicle weight detection device.

[0002]

[Prior Art]

 For example, in an automatic transmission of a vehicle, a shift map in which an optimum shift point is set in advance based on, for example, a vehicle speed and an engine load is used, and a shift can be automatically performed at an optimum shift point based on the driving state at that time. I am trying. However, the optimum shift point differs depending on the vehicle weight, and moves to the higher speed side as the vehicle weight increases. For this reason, conventionally, there is a vehicle equipped with an automatic transmission that has a plurality of shift maps according to the loading amount and selects an appropriate shift map according to the loading amount (for example, the actual development 61- No. 45649, etc.).

By the way, when selecting a shift map according to the vehicle weight, it is necessary to detect the vehicle weight. As a conventional vehicle weight detecting device, there are a method of calculating a loaded weight from a stroke amount of a vehicle suspension and its spring constant, a method of measuring from a strain generated on an axle, and the like.

[0004]

[Problems to be solved by the device]

 However, these conventional vehicle weight detection devices have a problem that it is necessary to measure the stroke amount in all vehicle parts and sufficient vehicle weight detection accuracy cannot be obtained due to the non-linearity and hysteresis. In addition, with the conventional method, even if it is possible to measure the loaded weight, the weight of the vehicle itself in the empty state will change if the equipment of the vehicle differs from the standard state due to addition of optional products or remodeling of the vehicle. There is a problem that measurement is impossible.

The present invention has been made in view of the above circumstances, and provides a vehicle weight detection device capable of accurately obtaining the vehicle weight regardless of the spring constant of the suspension and the like, regardless of whether the vehicle is loaded or unloaded. The purpose is to do.

[0006]

[Means for Solving the Problems]

 Therefore, the vehicle weight detection device of the present invention uses an engine torque detection means, a vehicle speed detection means, a vehicle acceleration / deceleration detection means, and an arithmetic expression of the vehicle running resistance based on these detected values and the specifications of the vehicle. And a calculation means for calculating the vehicle weight.

[0007]

[Action]

 With this configuration, the engine torque, the vehicle speed, and the acceleration / deceleration are detected. The running torque is balanced with the driving force of the wheels, which is obtained from the specifications of the vehicle such as the transmission gear ratio and the final reduction ratio based on the engine torque, and the running resistance of the vehicle. The vehicle weight is calculated from the detected values of the vehicle speed and acceleration / deceleration and the specifications of the vehicle by using an arithmetic expression of the vehicle running resistance. Therefore, the vehicle weight during traveling can be accurately estimated regardless of whether the vehicle is loaded or unloaded, and thus the control accuracy of various controls using the vehicle weight as a parameter can be improved.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1, which shows a hardware configuration of the present invention, an accelerator opening sensor 1 for detecting an accelerator opening corresponding to a load of an engine, a rotation sensor 2 for detecting an engine rotation speed, and a vehicle speed as vehicle speed detecting means. Each detection signal from the sensor 3 is input to a control unit 4 as an arithmetic means that incorporates a microcomputer. The control unit 4 calculates the output torque of the engine based on both detection signals from the accelerator opening sensor 1 and the rotation sensor 2. Further, the acceleration / deceleration of the vehicle is calculated based on the detection signal from the vehicle speed sensor 3. Then, the vehicle weight is calculated from the engine torque, the vehicle speed and the acceleration / deceleration, and the specifications of various vehicles to be described later, using an arithmetic expression of the vehicle running resistance as shown in the arithmetic processing routine of FIG. Here, the accelerator opening sensor 1, the rotation sensor 2, and the control unit 4 constitute an engine torque detecting means, and the vehicle speed sensor 3 and the control unit 4 constitute an acceleration / deceleration detecting means and an arithmetic means.

The detection of the engine torque and the acceleration / deceleration is not limited to the method of the above-described embodiment, and the engine torque may be detected from the output torque of the propeller shaft using, for example, a torque sensor. May be used for detection. Here, the vehicle weight calculation principle of the present embodiment will be described. Assuming that the running resistance of the vehicle is T _f , the equation for calculating the running resistance is as shown in the following equation (1).

T _f = μW + ρAV ² + (α / g) (W + ΔW) + W sin θ (1) where μ: rolling resistance, W: vehicle weight, ρ: air resistance coefficient, A: vehicle front projection area , ΔW: equivalent inertia weight of rotating part, α: acceleration / deceleration, sin θ: road surface gradient. The rolling resistance μ and the road surface slope sin θ are values that change according to road surface conditions, but the others are vehicle eigenvalues (vehicle specifications).

The running resistance T_fIs measured for each minute time ΔT. Where the current running resistance is T _f0 And the running resistance after ΔT is T_f1Assuming that there is no change in the road surface condition during the minute time ΔT, the rolling resistance μW and the gradient resistance Wsin θ are equal to_f0= ΜW + ρAV₀ ²+ (W + ΔW) (α₀/ G) + Wsin θ ・ ・ (2) T_f1= ΜW + ρAV₁ ²+ (W + ΔW) (α₁/ G) + Wsin θ ··· (3)

Next, (2)-(3) is calculated. T _f0 −T _f1 = ρA (V ₀ ² −V ₁ ² ) + (α ₀ −α ₁ ) (W + ΔW) / g (4) From the equation (4), W + ΔW = g [T _f0 −T _f1 − ρA (V ₀ ² −V ₁ ² )] / (α ₀ −α ₁ ) ·· (5) Further, when ΔW is 0.1 W, W = g [T _f0 −T _f1 −ρA (V ₀ ² −V ₁ ² )] / 1.1 (α ₀ −α ₁ ) ··· (6).

On the other hand, _assuming that the engine torques at the respective _{times of} the equations (2) and (3) are T _e0 and T _e1 and the driving forces of the wheels are T ₀ and T ₁ , T ₀ = (T _e0 · G _T · G _F · η) / R · · (7) T ₁ = (T _e1 · G _T · G _F · η) / R · · (8) where G _T : transmission gear ratio, G _F : final Reduction ratio, η: transmission efficiency, R: tire radius. These are eigenvalues (specifications of the vehicle) of the vehicle.

Since the vehicle travels in a state where the traveling resistance and the driving force are balanced, T _f0 and T _f1 in the equation (6) are _replaced with T ₀ and T ₁ in the equations (7) and (8). By substituting it and substituting it in equation (6), it becomes possible to calculate and estimate the vehicle weight W for each minute time ΔT while traveling. Next, the vehicle weight detection operation of this embodiment based on the above-described calculation principle will be described based on the calculation processing routine of FIG.

This routine is started in synchronization with the start of the engine, and after the empty weight W ₀ of the vehicle is set as the initial setting, it is periodically executed at a constant time interval ΔT. In step 1 (denoted as S1 in the figure, the same applies hereinafter), the signals of the accelerator opening, engine rotation speed, and vehicle speed are read. In step 2, the current engine torque T _en (n = 1, 2 ...) Is detected from the accelerator opening and the engine speed.

In step 3, the previous vehicle speed V_n-1And this vehicle speed V_nAnd the acceleration α_n(= V _n-1 -V_n) Is calculated. In step 4, the previous acceleration α_n-1And this acceleration α_nAnd whether or not there was a change in acceleration (α_n-1-Α_n= 0), the routine is ended if there is no change, and if there is a change, the process proceeds to step 5.

In step 5, the vehicle weight W _n of this time is calculated by the following equation using the equation (6) for calculating the vehicle weight based on the running resistance and the wheel driving force. _{W n = g K a (T} e (n-1) -T en) -K b (V n-1 2 -V n 2) / K c (α n-1 -α n) ····· ( 9) Here, K _a : (G _T · G _F · η) / R, K _b : ρA, K _c : 1.1.

In step 6, the moving average of the vehicle weight average value W _ave up to the previous time and the current vehicle weight value W _n obtained by the equation (9) is calculated by the following equation to finally calculate the vehicle weight W. Suru _{W = (1-K d)} W ave + K d W n ··· (10) where, K _d: is a filter constant _{(0 ≦ K d ≦ 1)} .

The vehicle weight W is output as a vehicle weight signal from the control unit 4. Then, in step 7, the vehicle weight W obtained by the equation (10) is used as the vehicle weight average value W for the next calculation. _ave . By calculating the vehicle weight in this way, it becomes possible to more accurately estimate the vehicle weight regardless of the state of the loaded vehicle or the empty vehicle, compared to the method of calculating from the suspension stroke amount, spring constant, etc. .. Therefore, for example, by incorporating a vehicle weight detection device related to the transmission control system, it becomes easy to change the shift map that determines the shift points for upshifting and shiftdown according to the vehicle weight, and moreover, while traveling. Since it will be changed based on the current vehicle weight, optimum gear shifting operation characteristics can be obtained.

Further, as in the present embodiment, by calculating the running resistance for each minute time and taking the difference, it is possible to eliminate the rolling resistance component μW and the gradient resistance component Wsin θ that change depending on the road surface condition. For example, since the calculation formula for the vehicle weight is only the specific resistance based on the specifications of the vehicle, only the existing sensors such as the accelerator opening sensor, the rotation sensor that detects the engine rotation, and the vehicle speed sensor can be used. Since the vehicle weight can be detected, the vehicle weight can be detected without using a new sensor such as a sensor.

[0021]

[Effect of the device]

 As described above, according to the present invention, focusing on the fact that the vehicle is traveling with the balance between the traveling resistance and the wheel driving force, the vehicle weight is calculated using the equation for the traveling resistance that depends on the vehicle weight etc. Since the estimation is performed, it is possible to more accurately estimate the current vehicle weight regardless of the loaded / empty state while traveling, as compared with the conventional method that detects the vehicle weight from the extension / contraction state of the suspension. It will be possible. Then, the control accuracy in various controls using the vehicle weight as a parameter can be improved.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation flowchart of the above embodiment.

[Explanation of symbols]

 1 Accelerator position sensor 2 Rotation sensor 3 Vehicle speed sensor 4 Control unit

Claims (1)

[Scope of utility model registration request] 1. A calculation for calculating a vehicle weight from an engine torque detecting means, a vehicle speed detecting means, an acceleration / deceleration detecting means for a vehicle, and the detected values and specifications of the vehicle using an arithmetic expression of a vehicle running resistance. And a vehicle weight detection device.