TECHNICAL FIELD OF THE INVENTION

This document describes a load-sensing element, a calculating unit and a method. More specifically, it describes a load-bearing element contained in a load-bearing vehicle component that is included in a connection between a wheel axle and the chassis of the vehicle.

BACKGROUND

In a vehicle, perhaps particularly a vehicle that occasionally drives with loads of various weights and volumes, such as a goods vehicle, a long-haul semi, a bus or the like, it is often desirable to obtain an estimate of the current total weight of the vehicle, including the load. This weight estimate can be used in a plurality of different calculations in the vehicle, e.g. to calculate fuel consumption, braking distance or the appropriate air pressure for the tires. A vehicle weight measurement can also be used, for example, to warn the driver against driving on roads/bridges where the maximum permissible weight would be exceeded, for example. Accidents can thus be avoided by means of a correct and current determination of the weight of the vehicle and its load.

A plurality of different measuring systems/weighing systems have been developed for this purpose. They are based, for example, on one of the following technologies, such as: angle sensors with linkage or the like for measuring the distance between axle and chassis; an- gle sensors for measuring spring strain or the distance between axle and chassis; wire strain gauges that are glued or bolted onto chassis components; load cells between chassis and body and/or load cells between chassis and body in combination with a pressure gauge in a hydraulic cylinder. The problem with the first three aforementioned technologies is that they are based on measuring a vehicle component that is designed to be a chassis component, with the requirements in terms of service life and durability to which it is necessarily subject, but not in terms of accuracy with respect to strain and deformation. Large manufacturing tolerances can often occur in this context. Such large tolerances entail that it is, in principle, impossi- ble to install these weighing systems without calibrating each individual one, which is time- consuming and thus expensive. Another conceivable solution is to fabricate the aforementioned chassis components with higher manufacturing tolerance. However, this becomes very expensive, and scarcely fulfils any function other than that of enabling measurement of the loaded weight of the vehicle.

One problem with the latter two methods mentioned above, i.e. those involving load cells 5 between chassis and body, is that they are expensive, add a great deal of weight and measure only the mass above the chassis. These systems are dependent upon the conformation of the body, and can result in many variants. These systems can also be difficult to install, which can thus be expensive. i o Yet another problem is that the load in a vehicle may become displaced while driving, e.g. when turning, as a result of centrifugal forces. The load can be damaged thereby. Furthermore, the vehicle handling may become degraded due to displacement of the center of gravity of the vehicle.

15 The need exists to be able to measure the current weight of a vehicle instantaneously, without time-consuming individual calibration of a measuring system for each vehicle.

SUMMARY

One object is consequently to develop weight measuring in a vehicle so as to solve at least 20 one of the aforementioned problems and thereby achieve improved weight measuring in the vehicle.

According to a first aspect, this object is achieved by means of a load-sensing element in a vehicle. The load-sensing element is arranged so as to determine the vehicle weight of the 25 vehicle, which comprises at least two wheel axles and a chassis. The load-bearing element is contained in a load-bearing vehicle component that is included in a connection between wheel axle and chassis in the vehicle, wherein the load-bearing vehicle component has a manufacturing tolerance that is below a set first limit value.

30 According to a second aspect, this object is achieved by means of a method in a calculating unit in a vehicle for determining the vehicle weight of the vehicle. The vehicle has at least two wheel axles and a chassis, plus a number of load-sensing elements. The method comprises the collection of respective measurement values from the load-sensing elements in the vehicle. The method further comprises the summing of the collected meas-

35 urement values. The method also comprises the calculation of the vehicle weigh of the vehicle, based on the summed measurement values, by converting them to a weight value, to which a constant corresponding to the weight of the vehicle on its wheels, wheel axles and suspension is added.

According to a third aspect, this object is achieved by means of a calculating unit in a vehi- 5 cle. The calculating unit is arranged so as to determine the vehicle weight of the vehicle. The vehicle has at least two wheel axles and a chassis, plus a number of load-sensing elements. The calculating unit comprises a communication module arranged so as to receive signals that represent a respective measurement value from all load-sensing elements in the vehicle. The calculating unit further comprises a processor arranged so as to i o sum the collected measurement values, and also arranged so as to calculate the vehicle weight of the vehicle, based on the summed measurement values, by converting them into a weight value, to which a constant corresponding to the weight of the vehicle on its wheels, wheel axles and suspension is added.

15 Thus, by disposing load-sensing elements in load-bearing vehicle components in a vehicle, wherein the load-bearing vehicle components are manufactured with a manufacturing tolerance that is below a limit value, a measuring system can be achieved for measuring vehicle weight in a reliable manner without the need for time-consuming and thus expensive individual calibration of the load-sensing elements in each vehicle. More reliable and im-

20 proved measurement of the weight of the vehicle compared with the prior art is achieved thereby.

Other advantages and additional new features will be presented in the detailed description below.

25

LIST OF FIGURES

Embodiments of the invention will now be described in greater detail with reference to the accompanying figures, which illustrate various exemplary embodiments:

30 Figure 1 A illustrates a scenario with a vehicle with a load-sensing element in a load- bearing component according to one embodiment.

Figure 1 B illustrates a load-sensing element according to one embodiment.

Figure 2A illustrates a scenario with a vehicle with a load-sensing element in a load- bearing vehicle component according to one embodiment.

35 Figure 2B illustrates a load-sensing element according to one embodiment. Figure 2C illustrates a load-sensing element according to one embodiment.

Figure 3 is a flow diagram that illustrates one embodiment of the invention.

Figure 4 is an illustration of a calculating unit in connection with a load-sensing element according to one embodiment of the invention.

5

DETAILED DESCRIPTION

Embodiments of the invention comprise a load-sensing element, a method and a calculating unit, which can be realized according to any of the examples described below. However, this invention can be realized in many different forms, and is not to be viewed as limited i o by the embodiments described herein, which are intended rather to elucidate and clarify various aspects.

Additional aspects and features of the invention may be apparent from the following detailed description when it is considered in conjunction with the accompany figures. Howev- 15 er, the figures are to be seen solely as examples of various embodiments of the invention, and are not to be viewed as limitative of the invention, which is limited solely by the accompanying claims. Furthermore, the figures are not necessarily drawn to scale and, unless otherwise stated in particular, are intended to illustrate aspects of the invention conceptually.

20

Figure 1A shows a vehicle 100 with a chassis 110. The vehicle 100 can be arranged so as to be loaded with a load and consists of, for example, a goods vehicle, long-haul semi, transport vehicle, car, emergency vehicle, bus, tank, motorcycle, fire engine, train, tram, amphibious vehicle or other similar motorized manned or unmanned means of transport 25 adapted for land-based geographical movement.

A load-bearing component 120 sits in the vehicle chassis 1 10. In the illustrated embodiment, the load-bearing component 120 consists of a spring bolt that secures the vehicle suspension 140 to the chassis 1 10 in a front bracket and a rear bracket. In this embodi- 30 ment there is thus a first spring bolt 120-1 and a second spring bolt 120-2, which secure the vehicle suspension to the chassis 1 10 for each wheel axle 130 in the vehicle 100. Other embodiments may comprise a different number of spring bolts 120.

Figure 1 B shows a load-bearing component 120 in the form of a spring bolt. This spring 35 bolt 120 contains a load-sensing element 150. Disposing the load-sensing element 150, which can consist of, for example, a sensor, a wire strain gauge, a load cell, a piezoelectric element or the like on a chassis component that bears the entire load weight, in this case the spring bolt 120 by means of which the vehicle suspension is secured, provides a weighing system that is inexpensive, accurate and also includes the chassis weight.

A strain gauge is a load-sensing element 150 that can be described as an electrical conductor with electrical resistance. When the conductor, i.e. the wire, is subjected to elongation or contraction, its resistance is changed. By measuring the change in resistance, it is possible to obtain an idea of how much and in which direction the material is being strained. Elongation causes increased resistance, and vice versa.

A load cell is a type of load-sensing element 150 that measures forces. They are normally used to measure weight or load. A load cell is normally designed using wire strain gauges connected in a Wheatstone bridge. Because the differential voltage typically measures up to just several tens of millivolts, an amplifier may be used in certain embodiments to read the signal from the load cell.

Disposing the load-sensing element 150 in the spring bolt 120, which is disposed between the wheel axle 130 and the spring 140 on all bearing wheel axles, makes it possible to measure the strain as a function of the entire vehicle mass, excluding axles and wheels. The weight of the wheel axles and wheels can, however, be measured or estimated separately and is assumed to be constant. This makes it possible to compensate for this in a weight calculation by adding a constant value. In certain embodiments, such compensation can optionally be made for dirt, clay and the like that is adhering to the wheel axles and vehicle underbody. The weight of this is low, or very low in relation to the total vehicle weight, perhaps on the order of 0-30 kg.

The spring bolt 120 is a relatively inexpensive and easily manufactured component that can be manufactured with high accuracy with no noteworthy added cost. Furthermore, spring bolts 120 are manufactured with measurement precision, since they are normally turned.

Yet another advantage of disposing the load-sensing element 150 in a spring bolt 120 that in turn secures the suspension 140 to the vehicle chassis 1 10 is that the load-sensing element 150 is not exposed to static load from the bolted joint. In addition, the sensor signal from the load-sensing element 150 is not affected by the rigidity of other components. This makes it possible to avoid the need to perform an individual calibration for each vehicle 100, which facilitates and lowers the cost of installation.

Figure 2A again shows a vehicle 100 with a chassis 1 10, quite like the vehicle 100 pre- 5 sented above in Figure 1 A. The vehicle 100 has a rear bogie wheel installation, which differs from the front axle schematically depicted in Figure 1 A. Here a spring 140 bears two wheel axles 130-1 , 130-2 that are suspended on a pivot, also known as a bogie frame. In the illustrated example, this spring 140 is not suspended on a bolt joint but rather rests against a spring seat 120-1 , 120-2 mounted respectively in the front bogie axle 130-1 and o the rear bogie axle 130-2.

Integrating a load-sensing element 150, e.g. in the form of a load cell, into each respective spring seat 120-1 , 120-2 makes it possible to achieve a weighing system that is inexpensive, accurate and also includes the chassis weight of the vehicle 100.

5

The load-sensing element 150 can, for example, be disposed in the spring seat body 120- 1 , 120-2 and a cover can be disposed on the load-sensing element 150 as a replaceable part, as this cover becomes worn as the spring 140 slides over the load-sensing element 150 on the spring seat 120-1 , 120-2.

0

One advantage hereof is that the load-sensing element 150 is protected from wear, and the replacement interval is extended. The placement of the load-sensing element 150 results in the entire vehicle mass being borne by the load-sensing element 150, regardless of disuniformities for which the bogie compensates. If the load-sensing element 150 is de-5 signed so that only the force vector in the vertical direction is measured, it is possible to eliminate any contribution from lateral loads and friction loads.

The placement discussed here is also advantageous from a service and installation perspective. The load-sensing elements 150 are integrated into small components that are0 easy to replace and sit protected; this also applies to the embodiment illustrated in Figures 1 A and 1 B. Furthermore, installation of a weighing system is enabled without the need to calibrate each individual load-sensing element 150.

Figure 2B shows a spring 140 in a bogie wheel installation, e.g. in the vehicle 100 that is5 illustrated in Figure 2A. One end of the spring 140 rests on a spring seat 120 in one of the wheel axles 130 of the vehicle. In certain embodiments, a load-sensing element 150 can be mounted in said spring seat 120. Said load-sensing element 150 can have a protective cover 160 mounted, which is arranged so as to be disposed between the load-sensing element 150 and the suspension 140 so that the load-sensing element 150 is protected against wear resulting from the movement of the suspension under load. The load-sensing element 150 can consist of a load cell, according to certain embodiments. Furthermore, the 5 load-sensing element 150 can be designed so as to sense forces solely in the vertical direction, according to certain embodiments.

Figure 2C shows the load-sensing element 150 that is illustrated in Figure 2B, with a protective cover 160 disposed on top of the load-sensing element 150 between the spring 140 i o and the load-sensing element 150 so as to reduce wear damage to the load-sensing element 150 when the spring 140 moves under load. The protective cover 160 can be made of, for example, an abrasion-resistant steel alloy; high-strength steel; an alloy contain wolfram carbide and cobalt; hard metal; ceramic-based material or the like.

15 Figure 3 illustrates an example of an embodiment of the invention. The flow diagram in Figure 3 illustrates a method 300 in a calculating unit 200 in a vehicle 100 for determining the vehicle weight of the vehicle 100. The vehicle 100 has at least two wheel axles 130 and a chassis 1 10, plus a number of load-sensing elements 150. At least one of said wheel axles 130 can consist of a bogie axle comprising a front axle 130-1 and a rear axle 130-1 ,

20 according to certain embodiments. Said load-sensing elements 150 in the vehicle 100 are arranged so as to determine the vehicle weight of the vehicle 100. Each such load-sensing element 150 is contained in a load-bearing vehicle component 120 that is included in a connection between a respective wheel axle 130 and the chassis 1 10 in the vehicle 100. Furthermore, the load-bearing vehicle component 120 has a manufacturing tolerance that

25 is below a set first limit value.

In order to be able to determine the vehicle weight correctly, the method 300 can comprise a number of steps 301-304. However, it should be noted that certain of the described steps 301 -304 can be performed in a chronological order other than that indicated by the numeri- 30 cal order, and that certain or a plurality of them can be performed in parallel with one another, according to different embodiments. Furthermore, certain steps are performed only in certain embodiments, such as e.g. step 302. The method 300 comprises the following steps:

35 Step 301

A respective measurement value from the load-sensing elements 150 in the vehicle 100 is collected. The measurement values can be received from the load-sensing elements 150 over a wire- bound or wireless interface, according to different embodiments.

The wire-bound interface can, for example, comprise or be based on a cable connection, an internet-connected network or a communication bus system consisting of one or more communication buses for connecting the enumerated units 150, 200 with one another or, alternatively, with other units such as a steering unit, control unit and/or sensors. The communication bus can consist, for example, of one or a plurality of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Oriented Systems Transport), or some other bus configuration. The wireless interface can be, for example, be based on or inspired by any of the following technologies: Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Code Division Access (CDMA), (CDMA 2000), Time Division Synchronous CDMA (TD-SCDMA), Long Term Evolution (LTE); Wireless Fidelity (Wi-Fi), defined by the Institute of Electrical and Electronics Engineers (IEEE) standards 802.1 1 a, ac, b, g and/or n, Internet Protocol (IP), Bluetooth and/or Near Field Communication, (NFC), or a similar communication technology, according to different embodiments.

The measurement values from the load-sensing elements 150 can be collected, e.g. con- tinuously during operation of the vehicle 100 or in individual measuring instances, according to different embodiments. For example, the calculating unit 200 can send a request for the measurement data at a set time interval, such as one day, one hour or one minute, or as a result of another event, e.g. in connection with the vehicle 100 being started or the driver requesting a measurement.

More reliable measurement data are obtained at frequent intervals. The calculating load on the calculating unit 200 is reduced in connection with less frequent measurement intervals.

Step 302

This method step can be included in some, but not necessarily all embodiments.

Collected 301 measurement values from load-sensing elements 150 disposed on different wheel axles 130 in the vehicle 100 and/or disposed respectively on the right and left sides of the vehicle 100 are compared. If the difference between these measurement values ex- ceeds a second limit value, a load-displacement warning can be triggered to draw the attention of the driver. Such a load-displacement warning can consist, for example, of a warning lamp being lit in the vehicle instrument panel, an auditory warning signal being triggered, or the like.

A displacement of the load in the vehicle 100 during travel can thus be detected and also 5 rectified by the driver before any accident occurs.

Step 303

The collected 301 measurement values collected from the load-sensing elements 150 in the vehicle 100 are summed.

10

Step 304

The vehicle weight of the vehicle 100 is calculated, based on the summed 303 measurement values, by converting said measurement values into a weight value to which a constant corresponding to the vehicle weight on its wheels, wheel axles 130 and suspension 15 140 is added.

For example, the measurement values can be stored in a table, or in a graph in which the measurement values and corresponding strain values are mapped against the weight values for the vehicle 100 and its load.

20

A continuously updated weight calculation for the vehicle 100 can thus be obtained, thereby enabling a more precise calculation of the vehicle weight to be used as a parametric value in the calculations performed in the vehicle 100, such as, for example, calculations of fuel consumption, feasible range with current fuel amount, braking distance etc.

25

Figure 4 shows an embodiment of a system 400 comprising a calculating unit 200 and load-sensing elements 150 in a vehicle 100. The system 400 is arranged so as to determine the vehicle weight of the vehicle 100, wherein the vehicle 100 has at least two wheel axles 130 and a chassis 1 10. At least one of said wheel axles 130 can consist of a bogie 30 axle comprising a front axle 130-1 and a rear axle 130-1 , according to certain embodiments.

The load-sensing element 150 is contained in a load-bearing vehicle component 120 that is included in a connection between a respective wheel axle 130 and the chassis 1 10 of the 35 vehicle 100, wherein the load-bearing vehicle component 120 has a manufacturing tolerance that is below a set first limit value. Said first limit value can be predetermined or configurable, according to different embodiments. The load-bearing vehicle component 120 can, in certain embodiments, consist of a spring bolt arranged so as to secure a wheel suspension 140, which is secured in the vehicle wheel axle 130, to the vehicle chassis 1 10. Furthermore, in certain embodiments the load- 5 bearing vehicle component 120 can consist of a spring seat in one of the vehicle wheel axles 130, on which a wheel suspension 140 rests, and which is secured to the vehicle chassis 1 10. Furthermore, in certain embodiments the vehicle 100 can comprise load- bearing vehicle components 120 of both said types, depending for example on the axle design, such as single axle or bogie axle, on different axles.

10

The load-bearing element 150 can, in certain embodiments, be arranged so as to measure loading solely in the vertical plane of the vehicle.

The load-sensing element 150 can also be arranged for the mounting of a protective cover 15 160. In certain embodiments this protective cover 160 can be disposed between the load- sensing element 150 and the wheel suspension 140 so that the load-sensing element 150 is protected against wear resulting from the movement of the wheel suspension under load.

In the latter case, the system 400 can also comprise such a protective cover 160 arranged 20 so as to be disposed between the load-sensing element 150 and the wheel suspension 140, so that the load-sensing element 150 is protected against wear resulting from the movement of the wheel suspension under load.

Furthermore, the system 400 also comprises a calculating unit 200 in the vehicle 100. The 25 calculating unit 200 is arranged so as to determine the vehicle weight of the vehicle 100, wherein the vehicle 100 has at least two wheel axles 130 and a chassis 1 10, plus a number of load-sensing elements 150.

Said calculating unit 200 comprises a communication module 410 arranged so as to re- 30 ceive signals that represent a respective measurement value from all load-sensing elements 150 in the vehicle 100.

The calculating unit 200 can be arranged so as to receive measurement data from the load-sensing elements 150 over a wire-bound or a wireless interface, according to different 35 embodiments. The wire-bound interface can, for example, contain or be based on a cable connection, an internet-connected network or a communication bus system consisting of one or more communication buses for connecting the enumerated units 150, 200 with one another or, alternatively, with other units such as a steering unit, control unit and/or sensors. The communication bus can consist, for example, of one or a plurality of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Oriented Systems Transport), or some other bus configuration. The wireless interface can be, for example, be based on or inspired by any of the following technologies: Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Code Division Access (CDMA), (CDMA 2000), Time Division Synchronous CDMA (TD-SCDMA), Long Term Evolution (LTE); Wireless Fidelity (Wi-Fi), defined by the Institute of Electrical and Electronics Engineers (IEEE) standards 802.1 1 a, ac, b, g and/or n, Internet Protocol (IP), Bluetooth and/or Near Field Communication, (NFC), or a similar communication technology, according to different embodiments.

The calculating unit 200 further comprises a processor 420 arranged so as to sum the col- lected measurement values, and arranged so as to calculate the vehicle weight of the vehicle 100 based on the summed measurement values. Such calculation of the vehicle weight of the vehicle 100 includes a conversion of the summed measurement values from the load-sensing elements 150 in the vehicle 100 into a weight value, to which a constant that corresponds to the vehicle weight on its wheels, wheel axles 130 and suspension 140 is added.

The processor 420 can, in certain embodiments, also be arranged so as to compare the collected measurement values from load-sensing elements 150 disposed on different wheel axles 130 in the vehicle 100, and/or disposed respectively on the right and left side of the vehicle 100, and so as to trigger a load-displacement warning for the driver if the difference between the compared values exceeds a second limit value. Said second limit value can be predetermined or configurable, according to different embodiments.

The processor circuit 420 can consist, for example, of one or more Central Processing Unit (CPU), microprocessor or other logic designed so as to interpret and carry out instructions and/or to read and write data. The processor circuit 420 can manage data for inflows, outflow or data-processing of data, also including buffering of data, control functions and the like. The calculating unit 200 can also comprise a memory unit 425 arranged so as to store, for example, a constant that corresponds to the vehicle weight on its wheels, wheel axles 130 and suspension 140, in certain embodiments. The memory unit 425 can consist of, for example, a memory card, flash memory, USB memory, hard drive or other similar data-storage unit, such as any from the group comprising ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), etc in different embodiments.

Furthermore, the calculating unit 200 can also comprise a signal transmitter 430 arranged so as to send wire-bound or wireless control signals in accordance with any of the aforedescribed communication technologies. For example, the signal transmitter 430 can send a request for measurement data to the load-sensing elements 150 in the vehicle 100. Furthermore, the signal transmitter 430 can send, for example, a control signal that initiates a warning to the vehicle driver that a load-displacement has occurred under certain circumstances when a difference in the measurement values exceeding a certain limit value is detected. An information unit 450 in the vehicle cab can then draw the attention of the driver to this. Such an information unit 450 can consist of an LED, a lamp, a loudspeaker that generates a warning sound, a display screen that displays a warning message, or a similar device. Furthermore, according to certain embodiments, the invention comprises a computer program in a vehicle 100, wherein the vehicle 100 has at least two wheel axles 130 and chassis 1 10, and comprises a number of load-sensing elements 150. The computer program is intended to determine the vehicle weight of the vehicle 100 by performing the method 300 according to at least one of steps 301 -304 when the computer program is executed in a processor 420 in a calculating unit 200 in the vehicle 100.

The method 300 according to at least one of steps 301 -304 can thus be implemented by means of one or more processor circuits 420 in the calculating unit 200 together with computer program code for performing one, several, certain or all of the steps 301 -304 as de- scribed above when the computer program containing instructions for performing said steps 301 -304 is loaded into the processor circuit 420.

The aforedescribed computer program can, in certain embodiments, be arranged so as to be installed in the memory unit 425, e.g. over a wireless or wire-bound interface, such as any of those enumerated above. The communication module 410 and/or signal transmitter 430 described and discussed above can, in certain embodiments, consist of a separate transmitter and receiver. However, the communication module 410 and signal transmitter 430 in the calculating unit 200 in the vehicle 100 can, in certain embodiments, consist of a transceiver that is adapted to both send and receive signals, such as radio signals, and wherein parts of the design, such as the antenna, if present, are common to both transmitter and receiver. Said communication can be adapted for wireless information transfer, via radio waves, WLAN, Bluetooth or an infrared transceiver module. However, the communication module 410 and/or signal transmitter 430 can, in certain embodiments, alternatively be specially adapted for wire- bound information exchange, or for both wireless and wire-bound communication, according to certain embodiments.

Some embodiments of the invention also comprise a vehicle 100 that contains a system 400 installed in the vehicle 100 and arranged so as to perform a method 300 according to at least one of the method steps 301 -304 and determine the vehicle weight of the vehicle 100.