JPH068744B2 - Vehicle load measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle weight measuring device, and by calculating a vehicle running resistance and an engine driving force by a predetermined input signal to obtain a road gradient. The present invention relates to a device that can accurately measure a loaded weight.

[Conventional technology]

Recent automobiles are equipped with a device for instructing the driver how to operate the gears (shift up, shift down). However, the conventional shift changing device does not consider the weight of the load, so the weight change For large freight vehicles, etc., it is not possible to accurately determine the shift change, it is not possible to ensure running stability on steep slopes, and the optimum gear is not selected, so fuel consumption is not improved and economic operation cannot be performed.

In order to deal with such a problem, the present applicant has disclosed in
-24621 proposed a shift change control device. As shown in FIG. 4, this device calculates a vehicle acceleration, a vehicle speed, an engine speed, an engine load, a load detection device 41, and a detection signal obtained from the detection device 41. A value corresponding to the running resistance is obtained from the acceleration, the declared load weight, and the final gear declared value, and the shift change is performed by the control device 42 that determines the optimum gear stage and the timing of the gear shift change. This is a shift changing device having an instructing device 43 for instructing, and by doing so, it becomes possible to enhance the running stability of the automobile and perform fuel-saving driving.

[Problems to be solved by the invention]

When carrying out fuel-efficient driving and stable driving of a car, especially on slopes, it is extremely important to change the gear position and the timing thereof. Therefore, accurate load weight and slope angle (road slope) of the driveway are required. Without knowing it, proper shift changes cannot be implemented.

By the way, in the shift changing device disclosed in the above-mentioned Japanese Patent Laid-Open No. 61-24621, although the loaded weight is taken into consideration, only the estimated weight of the loaded object is input. In other words, in reality, the exact weight is often unknown. For example, in the case of a freight vehicle, how many and how many pieces of goods are available (which is not known exactly because of packaging etc.), or in the case of a passenger car, how many people? And what kg
The estimated value is input like. Therefore, an error occurs between the actual weight and the estimated weight.

A means for automatically detecting the weight of a load is to detect the weight from the height relationship between the loading platform and the chassis only when the vehicle is stopped (for example, overload prevention described in Japanese Utility Model Publication No. 54-27414). Although there is a device), the detection accuracy is extremely poor due to deterioration of leaf springs, changes due to imbalance in load distribution, etc., and it cannot be used.

Therefore, an object of the present invention is to provide a vehicle load weight measuring device capable of always knowing an accurate load weight even while the vehicle is traveling.

[Means for solving problems]

As means for solving the above-mentioned problems, in a vehicle load weight measuring device according to the present invention, a vehicle speed, an engine speed and a fuel injection amount detecting means, a declared load weight input means, the speed and the declaration. Means for calculating the road gradient from the placement, engine speed and fuel consumption injection quantity, means for displaying the road gradient, and declared load weight corrected by the input means so that the road gradient matches the actual road gradient. And means for displaying.

[Work]

In the present invention, the road gradient is calculated and displayed from the declared values of the vehicle speed, the engine speed, the fuel injection amount, and the loaded weight. Then, the calculated load gradient is corrected by the declared load amount input means so that it matches the actual gradient displayed on the road sign or the like, and the declared load amount at the time of matching is displayed as the actual load amount.

〔Example〕

An embodiment of the vehicle load weight measuring apparatus according to the present invention will be described below.

First, in the present invention, the principle of detecting the road gradient as a pre-stage for obtaining the loaded weight will be described.

Now, assuming that the driving force of the vehicle is F, the running resistance is R, the acceleration is α, and the total weight is W, the relationship F = R + αW (1) holds, and the total weight W is the vehicle itself (empty state).
Weight W _{1 of,} loading weight W _2, and consists of the weight W _i corresponding to the moment of inertia determined by number i of gear in use, and _{W = W 1 + W 2 +} W i (2). However, the loaded weight W ₂ is a value estimated by the driver.

The running resistance R can be approximately expressed by R = θ (W ₁ + W ₂ ) + K ₁ (W ₁ + W ₂ ) + K ₂ V ₁ ² (3), where θ is the road slope. A related quantity (radian), K ₁ is a rolling resistance coefficient, K ₂ is an air resistance coefficient, and V ₁ is a vehicle speed to air. If the road gradient is δ, then δ = θ × 100 (%) (4) and the road gradient δ is δ = [F-α (W ₁ + W ₂ + W _i ) -K ₁ (W ₁ + W ₂ ) -K ₂ V ₁ ² ] × 100 /
(W ₁ + W ₂ ) (5)

Acceleration α is the amount of change in ground speed V ₂ during time ΔT Δ
From V ₂ , α = K ₃ (ΔV ₂ / ΔT) (6). However, K ₃ is a coefficient related to gravitational acceleration. Then, the driving force F of the vehicle is approximately obtained from the axial average effective pressure Pme of the engine as F = K ₄ · μ _i · Pme (7). Here, K ₄ is a coefficient determined by the type of engine, final gear, and tire mounted on the vehicle, and μ _i is the reduction ratio of the gear stage i in use.

The shaft average effective pressure Pme of the engine can be obtained from the Pme map as shown in FIG. 3 if the engine speed N and the fuel injection control voltage L are known.

However, when the exhaust brake is applied to the engine, it becomes larger than the negative Pme value on the map.
An accurate road gradient δ cannot be obtained without correction, so at that time, the correction amount is set to x and Pme (1 + x)
Should be adopted as the Pme value.

Finally, the road gradient δ is calculated from Eqs. (5) to (7) as follows: δ = [K ₄ · μ _i · Pme-K ₃ (W ₁ + W ₂ + W _i ) × ΔV ₂ / ΔTK ₁ ( W ₁ + W ₂ ) -K ₂ V ₁ ² ] × 100 / (W ₁ + W ₂ )
(8) and the variables W ₂ , W _i , V ₁ , V ₂ , μ _i and Pme are input,
If the coefficients K _{1 to} K ₄ are stored, the road gradient δ can be calculated by the equation (8).

FIG. 1 shows a hardware configuration diagram of an apparatus for measuring a loaded weight of a vehicle after detecting a road gradient based on the principle described above. Reference numeral 1 denotes an input processing circuit 2, a central processing unit (CPU) 3, the above-mentioned arithmetic expressions, constants W ₁ , W _i and μ.
_i , K _{1 to} K ₄ , a control unit including a memory 4 and an output processing circuit 5, 6 is a load weight (declared value) input device, 7 is an air vehicle detector, 8 is a ground vehicle speed detector, 9 Is an engine speed detector, 10 is a fuel injection control voltage detector, 11 is an exhaust brake actuation detector, 12 is a clutch actuation detector, 13 is a used gear stage detector, and is obtained from detectors 6 to 13. Based on the signal, the control unit calculates the above formula (8), displays the slope δ on the road slope indicator 14, and further displays the declared value by the load weight detector 6 and the corrected load weight. Written weight indicator 1
It is equipped with 5.

The ground vehicle speed detector 8 may be something like a magnetic pickup that detects the rotation speed of the axle, and the air vehicle speed detector 7 is a combination of a wind turbine and a generator, which is attached to the outside of the vehicle. Good.

Even if the vehicle speed to the ground is used as a substitute for the vehicle speed to the ground, the road gradient can be calculated, but an error occurs in the traveling resistance due to the headwind or the tailwind while the vehicle is running.Therefore, it is more accurate to use the vehicle speed detector. .

Further, the fuel injection control voltage can be obtained from the rack position of the injection pump, the control lever position, the air flow rate, the manifold boost pressure, and the like.

Next, FIG. 2 is a diagram showing a flowchart of a program stored in the memory 4 of the control unit 1, and the operation of the loaded weight measuring device of the vehicle will be described with reference to this flowchart.

First, since the driver does not know the load weight, the driver manually inputs the load weight W ₂ estimated using the load weight input device 6 (for example, a variable resistor). Similarly to this, the control unit 1 includes an anti-air vehicle speed detector 7, an anti-earth vehicle speed detector 8, an engine speed detector 9, a fuel injection control voltage detector 10, and a gear stage detector 13, which are respectively connected to the anti-air vehicle speed V ₁ and the ground. The vehicle speed V ₂ , the rotation speed N, the fuel injection control voltage L, and the gear i used are read and stored in the memory 4, and the loaded weight W ₂ declared by the loaded weight detector 15 on the loaded weight display 15 is read.
Is displayed. Further, the central processing unit 3 obtains the speed ΔV ₂ at ΔT time using the ground vehicle speed V ₂ and calculates the acceleration α of the vehicle (step S1).

Next, the clutch actuation detector 12 determines whether the "disengaged" clutch is "connected" (step S2). If the clutch is "disengaged", the road gradient δ cannot be calculated. Then, the step 8 ends without updating the δ display data on the display unit 14. When the clutch is engaged, the road gradient δ can be calculated, so the process proceeds to the next step S3.

In step S3, the engine speed N and the fuel injection control voltage L read in step S1 are used to determine the Pme value at that time from the Pme map shown in FIG.

When the Pme value is obtained, it is determined whether the Pme value is not negative (step S4). If the Pme value is positive or zero, the road gradient δ can be calculated using the Pme value, but when the Pme value is negative, the control force is large when the exhaust brake is operating. Therefore, if the road gradient δ is calculated using the Pme value as it is, an error will occur.

Therefore, it is determined from the output of the exhaust brake operation detector 11 whether the exhaust brake is operating (step S
5) If the exhaust brake is not operating, step S
The Pme value obtained in 3 is used as it is to move to the calculation of the road gradient δ, but if the exhaust brake is in operation, in order to prevent an error, the correction factor x (for example, 0.7) is taken into consideration. , PPme (1 + x) are adopted as the corrected Pme value (step S6).

Then, the reduction gear ratio μ _i stored in advance in the memory 4 for the used gear i read in step S1 is read out, and the driving force F of the vehicle is calculated based on the equation (7) (step S7).

When the driving force F is obtained, the weight W _i due to the moment of inertia and the vehicle weight W ₁ stored in advance in the memory 4 are read out, and the loaded weight (declared value) W ₂ and the vehicle speed to air read in step S1. Using V ₁ , the vehicle acceleration α calculated in step S1, and the vehicle driving force F calculated in step S7, the road gradient δ is calculated by the above equation (5) (step S8).

Then, the road gradient δ obtained in step S8 is displayed on the road gradient display 14 (step S9). This may be analog display as shown in FIG. 1 or digital display.

After that, steps S1 to S9 are repeated.

However, the displayed road gradient δ is merely an assumed value for the loaded weight W ₂ which is self-reported by the driver, and does not represent the actual loaded weight. Therefore, an accurate value can be obtained by performing the following operation.

First of all, the driver at the place where the road slope is displayed on the road sign or the map, or at the place where the slope can be clearly sensed (for example, a flat road), the road slope display 1
The load weight declared value is changed by the load weight input device 6 so that the number 4 matches the road gradient at those places.

When the road slope displayed in this way and the actual road slope are coincident with each other, the weight displayed on the load weight display unit 15 represents the actual and accurate load weight.

After that, if the declared value of the loaded weight is not changed (if it is the same load), the road gradient δ is calculated by the control unit 1 based on the detection signals of the detectors 7 to 13,
The road gradient display 14 displays an accurate road gradient δ during traveling.

The display 15 may display the total weight W ₁ + W ₂ + W _i calculated in the control unit 1.

〔The invention's effect〕

As described above, in the vehicle weight measuring device of the present invention,
Calculate the road slope based on the vehicle speed, engine speed, fuel injection, and the declared value of the load weight, and compare this with the actual road slope to correct the load weight to obtain the actual negative load weight. Therefore, the accurate load weight can be known even while the vehicle is traveling. As a result, it becomes possible to manage the operation of the loaded weight of trucks and the like.

Furthermore, once the declared value of the loaded weight is adjusted to the correct road slope, the control unit can calculate the accurate running resistance and the correct road slope will be displayed automatically.
It can function as a road gradient detection device.

Then, if such a load weight measuring device is applied to a shift changing device, an accurate shift changing instruction can be given by knowing an accurate road gradient and a load weight, and traveling safety on a steep slope can be secured, The optimum gear is selected, and the effect of improving fuel efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a hardware configuration diagram showing an embodiment of a vehicle weight measuring device according to the present invention, FIG. 2 is a flow chart diagram of a program executed by a control unit of the present invention, and FIG. FIG. 4 is a graph showing a map of the axial average effective pressure Pme, and FIG. 4 is a hardware configuration diagram of a shift changing device which has been conventionally used. In FIG. 1, 1 is a control unit, 4 is a memory, 6 to 13 are various detectors, and 14 and 15 are indicators. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] 1. A vehicle speed, an engine speed and a fuel injection amount detecting means, a declared load weight input means, and a means for calculating a road gradient from the speed, the declared load weight, the engine speed and the fuel injection amount. And a means for displaying the road gradient, and a means for displaying the declared load weight corrected by the input means so that the road gradient matches the actual road gradient. measuring device. 2. The vehicle load weight measuring device according to claim 1, wherein the vehicle speed includes an air vehicle speed and a ground vehicle speed. 3. The calculating means corrects the shaft average effective pressure when the exhaust brake is in operation when the engine shaft average effective pressure obtained from the engine speed and the fuel injection amount is negative. The loaded weight measuring device for a vehicle according to claim 1 or 2.