WO2006136648A1

WO2006136648A1 - A method and an apparatus for collecting information on the mass of load of a vehicle in heavy road traffic

Info

Publication number: WO2006136648A1
Application number: PCT/FI2006/000214
Authority: WO
Inventors: Kimmo ERKKILÄ; Nils-Olof Nylund
Original assignee: Valtion Teknillinen Tutkimuskeskus
Priority date: 2005-06-21
Filing date: 2006-06-19
Publication date: 2006-12-28
Also published as: FI20050670A0; FI119484B; FI20050670A

Abstract

In the method for collecting information on the load amount of a vehicle (1) in heavy road traffic, the dependence of work Wr required for moving the vehicle (1) upon the transition and the vehicle mass, is determined in advance. During a driving event, position data and operational data of the vehicle (1) is collected at time intervals and, on the basis of the position and operational data, the distance s covered by the vehicle (1) , the change Δh of elevation of the position, the change of speed v and the work W per formed for moving the vehicle, for the measurement period during a driving event, are determined. The load mass mload of the vehicle (1) is calculated by means of the dependence of the work Wr required for moving the vehicle upon the transition and the vehicle mass, as well as the distance s covered by the vehicle, the change Δh of elevation of the position, the change of speed v and the work W performed for moving the vehicle, during the measurement period, and the energy conservation principle. The information on the mass of the load of the vehicle (1) thus calculated is transferred to a central system collecting mass data for storing or further processing.

Description

A method and an apparatus for collecting information on the mass of load of a vehicle in heavy road traffic

Field of the invention The invention is related to collecting information on the loads of vehicles in heavy road traffic, in particular on the mass of load.

Background of the invention In terms of economical efficiency of the operation, energy consumption and emissions, as well as safety, the follow-up and managing of the transports in the heavy road traffic is a subject matter interesting both the companies in the field and various au- thorities. The fuel consumption during the transports, for example, is a quantity followed with interest by different actors, having both an economical and environmental impact. The fuel consumption can be influenced in several ways. Principally, the different vehicles are different as far as their energy economy is concerned, depending, for example, on the engine and the design of the vehicle in terms of aerodynamic resistance. The driver's driving style also has a very large influence. For bus traffic, for example, it has been estimated that, due to varying driving styles of different drivers, the savings in fuel consumption may even amount to 30%.

In addition to the choice of vehicle stock, the fuel consumption, and thus the costs for the op- eration, as well as the emissions harmful for the environment may be influenced by schooling the drivers and by working on the attitudes so as to favour an economical driving style. In principle, for example, different spurs bound to the energy efficiency of the 5 driving style would be possible. For comparing the economy between different vehicle stock alternatives and different drivers, however, it is necessary for all the factors having on impact on the results to be measured reliably enough, like the fuel consumed, the mass to be transported and the characteristic of the route. As a rule, the fuel consumption data is available in some form. So, for busses driving on standard routes, the fuel consumption could be an appropriate indicator but changes depending on the load, independent of the economy of the driving style, are caused in the fuel consumption, for example, by possible seasonal variations e.g. in passenger numbers. When comparing the economy or energy efficiency of the transports, the mass of the load may easily have an even greater importance in goods traffic. The largest ve- hide combinations permitted by Finnish legislation may have a load of approximately even forty thousand kilograms. Then, errors in estimating the amount of the load easily lead to even large errors in estimating the economy or energy consumption. At present, the mass estimations of a load can base on waybills or the so-called volume weight, the mass of the goods being estimated on the basis of the volume, irrespective of its quality. Using this method, it will be clear that determining the load is imprecise. The amount of the load of a vehicle is also related to a safety aspect. By the amount of the load, the behaviour of the vehicle, and even the durability of roads are effected resulting in dangerous situations caused by loads too large. For this rea- son, maximum mass limits have been set for each vehicle type naturally requiring control in order to be complied with. At present, the control mainly is effected by various movable or stationary weighing devices. Controlling on the basis thereof, including stopping a vehicle on the way for weighting it by means of a weighing apparatus, is both time-consuming and, inevitably, of random nature the major part of the transports not being included in the control.

In addition to the above-mentioned methods, also different mechanical methods are known for deter- mining the weight of a vehicle, typically based on sagging of the vehicle caused by the mass, or on the pressures in the bellows of an air spring suspension. Such means may include, for example, a simple scale and a sagging indicator for the vehicle, when ob- served, giving at least a rough estimation about the vehicle mass. In addition to the inaccuracy of the measuring result, forwarding the mass data also represents a problem in solutions like this. For the determination of the axle weight of a vehicle, methods basing on the measurement of tyre pressure of the vehicle have been suggested, too. For example in patent US6688168, a method is disclosed for determining the axle weight of a vehicle by means of tyre pressure and rolling radius of a wheel. The determination of the mass of a vehicle based on the axle weights of the different axles, however, is rather complicated.

From above it can be seen that there is a great need for a reliable load determination of heavy- duty vehicles that could be performed independently of time and location during driving, using as few means as possible, and most preferably automatically. Furthermore, in all the examples described above, it would be preferable if information on the amounts of the load in different vehicles could be collected for analysing and further using the data centrally.

Object of the invention

The object of the invention is to eliminate the aforementioned drawbacks. Particularly, it is an object of the invention to disclose a completely new method and apparatus for collecting information on the load of a vehicle in heavy road traffic, which collection of information may be accomplished during a driving event automatically without separate weighing procedures and appara- tuses.

Summary of the invention

The method for collecting information on the load of a vehicle in heavy road traffic is character- ised by what is said in Claim 1.

In the method, information is collected on the load of a vehicle in heavy road traffic. In particular, a vehicle in heavy road traffic means here lorries, articulate trucks, busses and the like used in road traffic. According to the invention, in the method, the dependence of the work W_r required for moving the vehicle upon the transition and the vehicle mass is determined. The determination can be done for each vehicle but, however, when there is a great num- ber of vehicles of the same type, it is preferred to use type-specific dependences once determined. Transition means here both the distance covered and the changes of elevation on the route. The mass of a vehicle means the overall mass including the mass of an unloaded vehicle itself and the mass of the load. Furthermore, from said dependence, for example, the work required for overcoming the frictional forces resisting the movement of the vehicle, in relation to the vehicle mass, can be determined. According to the invention, in the method, during a driving event, position data of the vehicle and, from the data bus of the vehicle, operational data of the vehicle are collected at specified time intervals and, based on the position and operational data, the distance s covered by the vehicle, the change Δh in the position of the vehicle, the change of speed v of the vehicle, as well as the work W performed for moving the vehicle, for a measurement period during the driving event, are determined. The operational data of the vehicle means, for example, information on the speed of the vehicle and operational data of the engine, like torque and engine speed. The distance s covered by the vehicle, the change Δh of elevation, and the change of speed v can all be determined by means of the position data but, on the other hand, for the determination of the distance and change of speed, for example, also the speed collected as operational data of the vehicle, and the duration of the measurement period can directly be utilised. In the newest heavy-duty vehicles, a data bus, typically electric, utilised for collecting operational data of the vehicle, acquiring information on the engine operation and moving states of the vehicle, already belongs to the standard equipment. Possible bus types are, for example, CAN (Controller Area Network) , FMS (Fleet Management Systems) and OBD (On Board Diagnostics) . The data bus provides information on the speed of the vehicle, torque of the engine, engine speed, and fuel consumption. In the method according to the invention, the mass mi_oad of load of the vehicle is calculated by means of the de- pendence of the work Wr required for moving the vehicle upon the transition and the mass, the distance s covered by the vehicle, the change Δh of height, the change of speed v, and the work W performed for moving the vehicle, for the measurement period, and the en- ergy conservation principle. According to the energy conservation principle, the work performed for moving the vehicle is equal to the work done for overcoming the forces resisting the movement of the vehicle, the change of potential energy of the vehicle and the change of motion energy of the vehicle, altogether. Since the transition, the speed and the work performed are known for the measurement period, as well as the work for moving the vehicle as a function of the mass and the transition of the vehicle, the vehicle mass as the only unknown factor in the energy conservation equation can be solved. According to the invention, also, the information on the vehicle mass is transferred for storing in the central system gathering mass data, or for further processing. The information on the mass of the load of the vehicle may be the mass of the load as such, or some quantity proportional to the mass of the load allowing the mass of the load to be determined therefrom in the central system. Further processing may be, for example, considering the energy effectiveness of the transports in a haulage company by comparing the mass data with the fuel con- sumption, or control of the maximum mass limits by authorities .

In an embodiment of the invention, driving tests are performed in order to find out the dependence of the work Wr required for moving the vehicle upon the transition and the vehicle mass. One can drive with loads having different sizes on a known standard route for determining the work thereby performed according to the operational data available from the data bus of the vehicle. In establishing the distance covered and the changes of height, a known route can be utilised, or a positioning system installed in the vehicle. As an alternative to the driving tests, the dependencies in question can be determined theoretically by calculating. In a preferred embodiment of the invention, the position data of the vehicle is collected by means of GPS satellite positioning equipment installed in the vehicle. This is helpful especially when acquiring heitgh data of the vehicle position but, also the other transitions may be determined using an apparatus like this. The positioning equipment can be used for collecting position data for a driving event as well as for possible driving tests. In the newest vehicles for heavy road traffic, GPS equipment is already installed, so any additional installations are not needed. In a preferred embodiment of the invention, operational engine data of the vehicle is collected from the data bus of the vehicle at time intervals during the driving event, and on the basis thereof, the actual engine powers Pi are determined. The work W performed in the measurement period for moving the vehicle is determined based on the actual engine powers Pi and the duration of the measurement period. The operational data of the engine is, for example, the above-mentioned torque and engine speed, from which the engine power can directly be calculated. Here- from, the power consumed by diverse additional equipment, and diverse power losses occurring, among others, in the transmission, must be subtracted in order to obtain the power directed to moving the vehicle. Since, according to its definition, work is equal to power multiplied by time, the work performed for moving the vehicle can be calculated from the actual powers. The time period for collecting the data can be, for example, one second. In an embodiment of the invention, the mass π*ioad of load is calculated by first determining, on the basis of the dependence of work W_r required for moving the vehicle upon the mass and transition of the vehicle, a factor K determining the influence of vehi- cle mass on the forces resisting the movement of the vehicle. After this, the energy conservation equation W = Kms + mgΔh + (mΔ(v²))/2 is solved, g being the gravity acceleration, in relation to the vehicle mass. From the mass m of the vehicle thus obtained, the known mass m₀ of an unloaded vehicle is subtracted. The forces resisting the movement of the vehicle mean here friction forces resisting the movement when driv- ing at a constant speed. The movement is also resisted by air resistance but, especially at low speeds, its meaning is negligible and can be ignored in the consideration without causing any big error. The first term on the right side in the energy conservation equation describes the work performed for overcoming the movement resistances, the second one the change of the potential energy of the vehicle, and the third one the change of the kinetic energy of the ve- hide.

In another embodiment of the invention, additionally to the previously above-mentioned work required for moving said vehicle, the dependence of the work W_ro required for moving an unloaded vehicle upon the transition and speed of the vehicle is determined. This can be done, for example, by means of driving tests. It is also possible to determine the dependence by calculating. In this application, the mass πWd ^{of tne} load is calculated by first determining, on the basis of the dependence of the work W_r required for moving the vehicle upon the mass and on transition of the vehicle, the factor K determining the influence of the vehicle mass on forces resisting the movement of the vehicle. Subsequently, the dependence of the work W_ro required for moving an unloaded vehicle upon the transition and the speed of the vehicle is compared with the distance s covered by the vehicle, the change Δh of height in the position of the vehicle, and the change of speed v of the vehicle, for the measurement period and, thus, the portion Wo of the work W performed during the measurement period, assigned to an unloaded vehicle, is determined. The portion Wi_oad of the work W performed during the measurement period, corresponding to the load, is deter- mined by subtracting from the performed work W the portion Wo corresponding to an unloaded vehicle. Finally, the energy conservation equation Wi_oad = Km_loadS + mi_oadgΔh + (mi_oadΔ(v²) ) /2 is solved, g being the gravity acceleration, in relation to the mass mi_oacι of the load. In this application, for determining the load, the mass of an unloaded vehicle needs not to be known. During the measurement period, the engine torque is preferably at least 70% of the maximum value of the torque of the engine in order to achieve a sufficient accuracy when determining the work done for moving the vehicle, and thus the load. At low torques, a major part of the power is consumed to different losses, and the determination of power used for actual moving of the vehicle is inaccurate. In many situations, said limit value is expedient but, on the other hand, depending on the vehicle and the situa- tion, it may be even lower, for example 50% of the maximum torque value allowing, however, the accuracy to remain sufficient.

The distance covered by the vehicle during the measurement period is preferably at least 50 me- tres in order to guarantee a sufficient accuracy of the position and operational data of the vehicle, needed for determining the load, and further of the determination of the mass of the load. The distance becoming shorter, the inaccuracy in determining the position data as well as the operational data of the vehicle is increased leading to faults in determining the load. This limit value also is an example for a limit value expedient for several situations but, again, depending on the vehicle and the situation, a sufficient determination accuracy also can be achieved by setting the lower limit for the distance covered during the measurement period lower.

In the method, during the driving event, the mass of the load preferably is calculated several times based on the different measurement periods, and from the results thus obtained, the average value of the measurement periods weighted by the lengths of the measurement periods is calculated for improving the calculation accuracy. In this way, the first estimate of the mass of the load possibly obtained already after a short driving, can be specified in the course of the driving event.

The information on the mass of the load of the vehicle is transferred to the central system preferably in the course of the driving event via wireless communication means. Such can be, for example, a GSM or GPRS transmitter. Alternatively, in another application of the invention, the information on the mass of the vehicle load is stored in an intermediate storage medium and, after the driving event, is transferred to the central system. The intermediate stor- age medium may be, for example, a memory card permitting the information to be stored by a computer or the like installed in the vehicle.

In the method of the invention, the collection of fuel consumption data may be incorporated. The information can be collected, like the other operational data of the vehicle, from the data bus of the vehicle and, together with the mass data, transferred to the central system.

The whole process, following the determina- tion of the work required for moving the vehicle, for determining the mass of the load of the vehicle and transferring the mass data to the central system, can be arranged as an automatic function controlled by a computer. So, the method of the invention does not require any unusual measures from the driver.

The apparatus according to the invention for collecting data on the load of a vehicle in heavy road traffic, is characterised by what is disclosed in Claim 12. According to the invention, the apparatus includes first determining means for determining the dependence of work W_r required for moving the vehicle upon the transition and the vehicle mass. Using the first determinating means, for example, position data and operational data of the vehicle during possible driving tests may be collected, and said dependences determined on the basis thereof. Furthermore, according to the invention, the apparatus contains collecting means for collecting position data of the vehicle, and collecting members for collecting the operational data of the vehicle during a driving event with speci- fied time intervals from an on-board data bus. The collecting means may be the same means also used for collecting position and operational data during driving tests. In modern vehicles for heavy road traffic, the data bus utilised in collecting operational data, typically an electric data bus collecting data on the engine operation and other operational information of the vehicle, is in most cases already present. Such being the case, the operational data may be obtained directly by joining the bus by suitable collection members. The collecting members may include, for example, a computer. In accordance with the invention, the apparatus also includes second determining means for determining, on the basis of the position and operational data, the distance s covered by the vehicle, the change Δh of elevation of the vehicle position, the change v of speed of the vehicle, as well as the work W performed for moving the vehicle, for a measurement period during the driving event, . The second determining means may be the same means also used for determining the corresponding qualities during possible driving tests. These means may include, for example, a computer allowing said quantities to be calculated on the basis of the position data and operational data. According to the invention, the appara- tus also contains calculating means for calculating the mass mi_oad of the vehicle load by means of the dependence of the work W_r required for moving the vehi- cle upon the transition and the vehicle mass, the distance s covered by the vehicle, the change Δh of elevation of the position, the changes of speed v and the work W performed for moving the vehicle, for the meas- urement period, as well as the energy conservation principle. The calculating means may include, for example, a computer possibly being the same computer included in the above-mentioned second determinating means. Additionally, in accordance with the inven- tion, the apparatus further includes transfer means for transferring the information on the mass of the load of the vehicle to a central system collecting mass data.

In an embodiment of the invention, the col- lecting means contains GPS satellite positioning equipment installed in the vehicle for collecting the position data of the vehicle. In the newest vehicles, such is often ready installed.

Furthermore, the apparatus may contain third determining means for determining the dependence of the work W_Eo required for moving an unloaded vehicle upon the transition and the speed. Preferably, the third determinating means is the same as the first determinating means previously mentioned. The transfer means preferably includes wireless communication means for transferring the information on the mass of the load of the vehicle wirelessly to the central system. Such a transmission means may be, for example, a GSM or GPRS transmitter connected with a computer used for calculating the mass of the load. Alternatively, the transfer means may include an intermediate storage device for storing the mass data and, after the driving event, transferring it to the central system. Such a storage device may be, for example, a memory card permitting the mass data to be stored thereon by the computer used for calculating. The above-mentioned computer used for different functions may be an on-board computer ready installed in the vehicle, or some other electric control unit, for which the necessary additional functions may be provided via software. Thus, the invention can be implemented using just a few additional devices.

The invention provides several remarkable advantages over prior art solutions for collecting information on the mass of the load of a vehicle. Firstly, no separate weighing apparatuses are needed, since the mass can be determined in the course of a driving event, based on position and operational data of the vehicle. Doing so, the determination of the mass also is remarkably quickened compared to separate weighing. In relation to the volume weight method, for example, the accuracy of mass determination also is essentially increased. After determining the work required for moving the vehicle, carried out in advance, for example, by means of driving tests, the de- termination of the overall mass of the load, and forwarding the mass data to the central system, can be arranged to occur automatically, as controlled by a computer. In the invention, the equipment already existing in the vehicle can be utilised which, in addi- tion to being simple, permits low costs. Thus, the invention provides a highly effective and reliable way for real-time collection of load data from a large number of vehicles on road, which is a remarkable development step for a haulier following the economy of the driving style of his drivers as well as for authorities examining the emissions of traffic in relation to transported ton amounts. List of drawings

In the following, the invention is described in more detail using examples of embodiments, with reference to the accompanying drawings in which Fig. 1 shows one embodiment of the invention as a function diagram, and

Fig. 2 shows an apparatus according to the invention, and the operation thereof.

Detailed description of the invention

In the scheme of Fig. 1, the steps of the invention are presented. They are shown as two main steps, in the first one of which the amount of the load is determined, and in the second one of which the information on the load is transferred to a central system. According to the figure, the first main step is divided into several partial steps. In the method illustrated in the figure, driving tests first are performed by the vehicle with different loads, on the grounds of which the dependence of the work W_r required for moving the vehicle upon the transition and the mass as well as the speed of the vehicle is determined. On the basis of this dependence, a factor K is first determined determining the vehicle mass to forces resisting the movement of the vehicle. Secondly, the work. W_ro required for moving an unloaded vehicle in relation to the distance covered by the vehicle, and the change of height and the change of speed is determined. During a driving event, position data is collected at specified time intervals by means of GPS positioning equipment installed in the vehicle, and operational data of the vehicle is collected from the on-board data bus. Basing on the position data, the distance s covered by the vehicle and the change Δh of height in the vehicle position for the measurement period during the driving event, and, basing on the operational data, the change v of speed of the vehicle, are determined. Furthermore, basing on the operational data of the engine, the actual motor powers Pi of the vehicle, and basing thereon and on the dura- tion of the measurement period, the work W performed for moving the vehicle during the measurement period, are determined. On the basis of the work W_r0 required for moving an unloaded vehicle, and the transition and speed information, the share Wo of the unloaded vehicle of the work W performed for moving the vehicle during the measurement period, is determined. The share of the load Wi_oad from the performed work is determined by subtracting the share W₀ of an unloaded vehicle from the overall work W performed for moving the vehicle during the measurement period. Following this, the mass mi_oad of the load is calculated by solving the corresponding energy conservation equation Wioa_d = Kmioa_dS + iriioa_dgΔh + (mio_adΔ (v² ) ) /2 , g being the gravity acceleration. In this method, the information on vehicle mass first is stored on the memory card and, subsequent to the driving event, transferred to the central system.

In Fig. 2, the apparatus used for collecting load data is shown. The vehicle 1 includes GPS positioning equipment 2 for collecting the position information of the vehicle. The positioning equipment is connected with a computer 3 in which the position data can be collected. The computer 3 also is connected to an on-board data bus 4 for collecting operational data from the data bus. By means of the computer 3, from the position data and the operational data, the transitions s and Δh as well as the changes of speed v of the vehicle, and the work performed for moving the ve- hicle, can be determined. The positioning equipment and the computer may be used for collecting and processing data during a driving event, and during driving tests possibly performed in advance. By means of computer 3, also the dependence of the work required for moving the vehicle upon the transition and vehicle mass and, if required, upon the speed, can be determined from the data of the driving tests. Further- more, the mass mi_oad of the load of the vehicle finally can be calculated by means of the computer. In addition, a GSM transmitter 5 has been connected with the computer 3 for wireless transfer of the information on the load mass to a central system 6 collecting mass data .

The invention is not limited to the above- mentioned embodiments but, many modifications are possible within the scope defined by the claims.

Claims

1. A method for collecting information on the load amount of a vehicle (1) in heavy road traffic, characterised in that the dependence of work W_r required for moving the vehicle (1) upon the transition and the vehicle mass is determined in advance; during a driving event, position data of the vehicle (1) and, from the data bus (4) of the vehicle, operational data of the vehicle is collected at time intervals; on the basis of the position and operational data, the distance s covered by the vehicle, the change of height Δh in the position of the vehicle, the change of speed v of the vehicle, and the work W performed for moving the vehicle, for a measurement period during the driving event, are calculated; the mass mio_ad of the load of the vehicle (1) is calculated by means of the dependence of work W_r required for moving the vehicle upon the vehicle transition and mass, as well as the distance s covered by the vehicle, the change Δh of height in the position, the change of speed v, and the work W performed for moving the vehicle, for the measurement period, as well as the energy conservation principle; and the information on the mass of the load of the vehicle (1) is transferred to a central system (6) collecting mass data for storing and further processing.

2. Method according to Claim 1, characterised in that driving tests are performed to determine the dependence of work W_r required for moving the vehicle (1) upon the transition and the vehicle mass .

3. Method according to Claim 1 or 2, characterised in that position data of the vehicle (1) is collected using GPS satellite positioning equipment (2) installed in the vehicle.

4. Method according to any of the Claims 1 to

3, characterised in that during the driving event, from the data bus (4) of the vehicle (1), operational data of the vehicle engine is collected at time intervals, and the actual engine powers P± of the vehicle are determined on the basis thereof; and on the basis of the actual engine powers Pi and the duration of the measurement period, the work W performed for moving the vehicle (1) during the measurement period is determined

5. Method according to any of the Claims 1 to

4, characterised in that the mass mi_oad of the load is calculated by determining, on the basis of the dependence of work W_r required for moving the vehicle (1) upon the vehicle transition and mass, a factor K determining the influence of the vehicle mass on forces re- sisting the movement of the vehicle ; by solving the energy conservation equation W = Kms + mgΔh + (mΔ(v²))/2, g being the gravity acceleration, in relation to the vehicle mass m; and by subtraction from the vehicle (1) mass m thus obtained the known mass mo of an unloaded vehicle .

6. Method according to any of the Claims 1 to 4, characterised in that, additionally, the dependence of the work W_ro required for moving an unloaded vehicle (1) upon the transition and the speed of the vehicle is determined in advance, and the load mass mi_oad is calculated by determining, on the basis of the dependence of work W_r required for moving the vehicle (1) upon the vehicle transition and mass, a factor K determining the influence of the vehicle mass on forces resisting the movement of the vehicle ; by comparing the dependence of the work W_ro required for moving an unloaded vehicle (1) upon the transition and the speed of the vehicle with the distance s covered by the vehicle, the change Δh of height in the position of the vehicle, and the change of speed v of the vehicle, for the measurement period, and, basing on the comparison, by determining the share W₀ of work W performed during the measurement period, corresponding to an unloaded vehicle; by determining the share Wi_oad of the work W performed during the measurement period, corresponding to the load, by subtracting the share Wo corresponding to an unloaded vehicle (1) from the performed work W; and by solving the energy conservation equation

Wi_oad = KmioadS + rrii_oadgΔh + (mi_oadΔ(v²) ) /2, g being the gravity acceleration, in relation to the mass mi_oad of load.

7. A method according to any of the previous Claims, characterised in that, during a measurement period, the engine torque of the vehicle (1) is at least 70% of the maximum value of the engine torque in order to guarantee sufficient accuracy while determining the work performed for moving the vehicle, and thus further the load.

8. A method according to any of the previous Claims, characterised in that, for guaranteeing a sufficient accuracy in determining the position and operational data of the vehicle required for determin- ing the load and, furthermore, the mass of the load, the distance covered by the vehicle (1) during a measurement period is at least 50 metres.

9. A method according to any of the previous Claims, characterised in that, on the basis of the different measurement periods, the mass of the vehicle load is calculated several times during a driving event, and from the results thus obtained, the av- erage value weighted by the durations of the measurement periods is calculated in order to improve the accuracy of calculation.

10. A method according to any of the previous Claims, characterised in that, during a driving event, the information on the mass of load of the vehicle (1) is transferred to a central system (6) by means a wireless communication means (5) .

11. A method according to any of the Claims 1 to 9, characterised in that information on the mass of the load of the vehicle (1) is stored on an intermediate storage device and transferred to the central system (6) after the driving event.

12. An apparatus for collecting information on the load of a vehicle (1) in heavy road traffic, characterised in that the apparatus includes first determining means (2, 3) for determining the dependence of work W_r required for moving the vehicle upon the transition and vehicle mass; collecting means (2, 3) for collecting position data of the vehicle (1), and collecting members (3) for collecting operational data of the vehicle at time intervals from an on-board data bus (4) during a driving event; second determining means (3) for determinating, on the basis of the position and operational data, the distance s covered by the vehicle (1) , the change Δh of height in the position of the vehicle, the change of speed v of the vehicle, and the work W performed for moving the vehicle, for a measurement period during the driving event; calculating means (3) for calculating the mass mi_oad of the load of the vehicle by means of the dependence of the work W_r required for moving the vehi- cle upon the transition and the vehicle mass, as well as the distance s covered by the vehicle, the change of heitgh Δh of elevation in the position, the change of speed v, and the work W performed for moving the vehicle, for the measurement period, as well as the energy conservation principle; and transfer means (5) for transferring the in- formation on the load vehicle mass to a central system (6) collecting mass data.

13. An apparatus according to Claim 12, characterised in that the collecting means include GPS satellite positioning equipment (2) in- stalled in the vehicle, for collecting position data of the vehicle.

14. An apparatus according to Claim 12 or 13, characterised in that, additionally, the apparatus includes third determining means (2, 3) for deter- mining the dependence of the work W_r0 required for moving an unloaded vehicle upon the transition and the speed of the vehicle.

15. An apparatus according to any of the Claims 12 to 14, characterised in that the transfer means comprise a wireless communication means

(5) for transferring the information on the load mass of the vehicle (1) wirelessly to the central system

(6) .

16. An apparatus according to any of the Claims 12 to 15, characterised in that the transfer means comprise an intermediate storage device for storing the mass data and transferring it by means of the intermediate storage device to the central system (6) after the driving event.