AU2009200620B2 - A Method for Logging the Performance of a Vehicle Suspension System - Google Patents

Abstract

Abstract A method for logging the performance of a vehicle suspension system including the steps of measuring the dynamic effect of an impulsive load with an electronic weighing 5 system, wherein the electronic weighing system is mounted onboard the vehicle, and determining one or more parameters selected from the group consisting of the dampening ratio of the suspension, the oscillation frequency of the suspension and the impact loading of the vehicle. cq\ 9u 1 0c I '(0 (Io c- co

Description

1 A METHOD FOR LOGGING THE PERFORMANCE OF A VEHICLE SUSPENSION SYSTEM Field of the Invention. The present invention relates to vehicle suspension systems and in particular to a 5 method for logging the performance of a vehicle suspension system in reaction to impulsive loads applied thereto. Background Art. Methods for testing the performance of vehicle suspension systems are generally known. 0 Automotive vehicles commonly employ a suspension system connected between the road wheels and the body of the vehicle. Conventional shock absorbers typically have a limited operating life, and therefore may need to be replaced when they no longer function properly. In order to determine if a shock absorber needs to be replaced, the simplest and most widely used conventional [5 diagnostic testing approach typically involves a technician applying force to the vehicle fender, or elsewhere on the vehicle body, and visually detecting the rocking movement response of the vehicle. The resulting oscillations are often counted visually or by an oscillation measuring device attached to the vehicle. The conventional suspension testing approach therefore involves subjective interpretation by the technician which may not be 20 consistently reliable. As can be appreciated, this test cannot feasibly be applied to large vehicles such as road haulage trucks and the like. Another test which may be applied is the European Drop Test, in which a set of axles is mounted on a test rig and is driven over an inclined ramp with a sheer drop of 25 approximately 80 mm on its facing edge. The damping ratio and frequency of the suspension is then measured using load cells attached to the test rig. The results gained in the above manners may be inaccurate and inconclusive in that they do not accurately take into account the combined effect of vehicle weight, suspension geometry and shock absorber characteristics as they relate to the efficiency of the shock 30 absorber in maintaining the vehicle's wheel in contact with the road surface having regard to the road bumps which the vehicle normally encounters. Also these simple tests do not take 2 into account multiple axles coupled together in what is commonly called a suspension group, for example, a tandem axle group, tri axle group, quad axle group, and the like. Other known devices for testing shock absorbers test the dynamic reactions of suspension. Some of these devices require the removal of the shock absorbers from the 5 vehicle. This practice is highly impractical for two reasons. First, labour costs involved in the shock absorber's removal for testing and subsequent reinstallation are prohibitive, in that such costs may be equal to or greater than the cost of replacement shock absorbers. This is particularly true with shock absorbers founded in MacPherson-type suspensions wherein removal of the shock absorber necessitates the disassembly of other suspension components, .0 such as the spring, ball joint and brake assembly. Second, testing of a shock absorber isolated from its operating environment is believed to be unsatisfactory as its damping ability is measured against an arbitrary standard rather than relative to the suspension system of which it is a part. As the performance of the shock absorber in conjunction with the rest of the suspension system affects the handling, [5 ride, suspension performance, stability and safety of the vehicle, the practice of shock absorber testing as an isolated component can be seen to be unsatisfactory as a method of determining in-service performance of the suspension, or a suspension group as a whole unit in an operating environment. As the shock absorber must be removed from the vehicle in order to test its 20 performance using this test, the vehicle must be removed from service for the length of the tests. This results in a loss of profits for the owner operator while the vehicle cannot be used during the period of downtime. Other devices currently on the market, namely those operating on the seismograph principal evaluate the suspension systems as a whole, but are restricted to recording 25 movement of the vehicle's body without allowing the deduction of the damping factor of the system, (i.e., shock absorber performance). With the advent of the Intelligent Access Project (IAP) under the NRTC guidelines and with the future introduction of Performance Based Standards (PBS), haulage or freight trucks may be called upon to comply with these standards which relate to the performance of 30 suspension and suspension components, as a whole or as a group of axles, so equipped. Under the IAP and the PBS guidelines, the vehicle suspension may be required to meet performance standards in order to maintain the compliance of the vehicle and its fitness for 3 service. This compliance testing may test one or more parameters of the suspension which determine the "road friendliness" of the suspension. A "road friendly suspension" may be one which functions within predetermined limits for one or more of the parameters, and attaining or complying with "road friendliness" may provide advantages for the 5 owner/operator of the vehicle such as the ability to carry heavier loads or access to roads which non-compliant vehicles may be restricted from using. As well, the road friendly performance of the suspension/s will affect the working life of the road itself with attendant reduction in maintenance costs and increased safety to all road users, with the economic benefits of such savings flowing on to the general community. 0 The compliance of the suspension is generally tested periodically over the life of the vehicle or of the vehicle suspension. It is therefore desirable to provide for an accurate test procedure for testing the performance of suspension components on a vehicle to determine whether the suspension is functioning properly and within legally acceptable limits while the vehicle is in use and .5 without requiring the removal of the vehicle from service. In addition, it is desirable to provide for a test procedure for testing vehicle suspension components that does not require subjective interpretation by a technician. Summary of the Invention. The present invention is directed to a method for logging the performance of a vehicle 10 suspension system, which may at least partially overcome the abovementioned disadvantages or provide the consumer with a useful or commercial choice. In one form, the invention resides in a method for logging the performance of a vehicle suspension system including the steps of measuring the dynamic effect of an impulsive load with an electronic weighing system, wherein the electronic weighing system is 25 mounted onboard the vehicle, and determining one or more parameters selected from the group consisting of the dampening ratio of the suspension, the oscillation frequency of the suspension and the impact loading of the vehicle. The method given above is preferably used to test the "road friendliness" of a suspension of vehicles. "Road friendliness" is assessed by the National Road Transport 30 Commission (NRTC), and once a road friendly standard has been attained, the vehicle is generally allowed increased mass limits. The road friendliness of a suspension or suspension group, that is two or more axles connected together for load sharing as defined in the 4 guidelines of the Higher Mass Limits (HML), is generally assessed under the current Higher Mass Limits (HML), currently in force, according to two criteria, namely the damping ratio of the suspension and the frequency of oscillation of suspension in response to an impulsive load. 5 In order to be considered road friendly, suspensions must have a damping ratio of greater than 20 percent, meaning that the reduction in the amplitude of oscillations which suspension undergoes in response to an impulsive load should decrease by greater than 20 percent after each oscillation. In addition to the required damping ratio in order to be considered road friendly, 0 suspensions should have a frequency of oscillation of less than 2 Hz. Preferably, components of an electronic weighing system mounted on board the vehicle may be used to measure and/or collect the data used according to the method of the present invention to calculate the damping ratio and frequency of oscillation. Typical electronic weighing systems may comprise at least one load measuring element, usually a .5 load cell or pressure transducer, each associated with one or more suspension component. Each load cell or pressure transducer may also be associated with a signal amplifier. Each signal amplifier may be associated with a central power module and a meter to display the data and/or the collated results of the tests performed. According to a particularly preferred embodiment, the signal amplifiers used ZO according to the present invention may be "smart" amplifiers. These amplifiers may be capable of storing the results of calibration testing produced according to the invention. In this way, the calibration results are stored in each "smart" amplifier associated with each load cell or pressure transducer and are therefore not dependent on information storage in the meter. 25 The meter may preferably include a display, generally located in the cabin of the vehicle allowing review or the data or results by a driver. The meter may also be associated with one or more remote display units and/or meters such as a computer allowing review of the information gathered according to the method of the present invention, from a location remote from the meter located in the cabin of the vehicle. 30 Preferably, each suspension component may be provided with a load cell or pressure transducer. Accordingly, a central meter may be provided to which all load cells or pressure 5 transducers transmit the data. Such transmission may be along cabling or may be wireless transmission of data. Suitably, the meter may be a multi-channel meter capable of receiving information from up to eight or more channels. Preferably each of the channels may receive data from an 5 axle grouping. Further, up to eight or more load cells and/or pressure transducers may provide information to the meter on each channel. Therefore, a single meter may be capable of receiving and recording information from a total of up to at least 64 load cells or pressure transducers. Each meter or system may preferably comprise an on-board storage device either built 0 into the system or attached thereto such as a data log/logger which suitably receives and records all information from all associated load cells or pressure transducers. The data log/logger may preferably allow the tracking of the information collected according to dates, times, and particular dynamic parameters such as the dynamic mass excursions, the G-force and time, both of which can be either pre-set or varied to suit particular operating conditions .5 and/or test conditions which may be varied to allow/achieve certain or specific data, according to either the owner's interests or that of a particular authority or body who has a right to such information. Accordingly, all data collected may be provided with an identification code allowing the tracking of the data. Typically, the meter from a single vehicle may be capable of communication with a 20 tool for analysis of the collected information, the analysis tool may be on-board either as a separate tool or built in to the system. In order to transmit and/or receive the information, the meter or system in general, may be provided with a means for transmitting and/or receiving information. The means for transmitting and/or receiving information may preferably be in the form of an interconnecting cable, radio frequency data link, a telephonic link or any other 25 type of the means for transmitting and receiving information. According to the present invention, each vehicle utilising the method of the present invention may be provided with a vehicle locating means. According to a particularly preferred embodiment, the vehicle locating means may preferably be a satellite global positioning system. However, other locating means, such as trip meters, may be used 30 according to the invention. The method may utilise one or more remote interrogation units adapted to allow remote access to the meter provided in a vehicle. The remote interrogation units may allow 6 the viewing and /or analysis of information collected on a real time basis, or on a later time basis, that is, at the discretion of the operator or the body requiring such data. According to a first particularly preferred embodiment of the invention, the performance of the vehicle suspension system is logged over a test track or a standard or 5 specific road section at different times. This performance logging may be termed an "axle test". The purpose of the axle test may be to test the performance of an individual axle or group of axles to an impulsive load and compare the results of the performance to the standards specified for road friendliness. The axle test may be performed when the suspension is new in order to establish compliance with the road friendliness criteria and to 0 act as a reference to measure the suspension or suspension group's compliance and wear over a period of time. The axle test may be conducted at various periods throughout the life of the suspension over the same test track or the same section of road in order to ensure that the performance of the suspension remains within the accepted standards. The axle test may be .5 conducted while the vehicle is in service and therefore may be termed "in service compliance" testing. Each of the parameters may be calculated from the data collected during any or all of the tests. The axle test may comprise a step test in which a specified height step downward is used to create a negative step input to the vehicle suspension for the purpose of determining M0 damping ratio and fundamental frequency of axle-to-body bounce of the suspension. The step test may be conducted over a predetermined height step and also at a predetermined speed of passing over the step. The method may further allow the adaptation of the data to allow for differences in the speed and height of the step when calculating the tested parameters. A second test which may suitably be used in axle testing is a bump test. This test may 25 generally comprise a series of tests performed by driving a combination test rig vehicle over a nominal 50mm bump (or other predetermined dimension) at approximately 5 km/h or at some other speed, as deemed necessary. The bump may extend upwardly or downwardly and may provide an approximation to a positive impulse signal applied to the suspension of the combination test rig vehicle. 30 A third test which may be performed may be a road test. According to this test, the variation in the mass signal may be recorded as the combination test rig vehicle travels along a specific section of a particular road or over a normal, uneven road at speed. The speed may 7 be up to 60km/h or may be higher or lower if required. The GPS location device may be linked to the data collected, during the time the data was collected, to precisely locate the portion of road upon which the test was conducted for future comparison of the test conditions as well as the road condition to determine the degradation in either or both. 5 Any one or more of the three tests described above may be conducted in order to assess the performance of the suspension as well as the condition of the road itself. According to a second particularly preferred embodiment of the invention, the performance of the vehicle suspension system is logged over a road section which is varying in its condition as laid or in its current state of repair at different times, the position of the 0 vehicle on this section of road being identifiable at all times during the logging process. This testing procedure may be termed a "trip test". The trip test may preferably allow data to be collected about the condition of the roads, or of a specific section of a road which a test vehicle travels over whilst gathering data in the form of the axle test for analysis, at the same time. Each trip test may be expanded into a series of axle tests for such purposes. For 5 example, an impulsive load may be imposed on the suspension if the test vehicle drives over a pothole in the road. If a test vehicle uses the same route, it would generally traverse the same pothole on different trips. By assessing the performance of the suspension in response to the impulsive load applied to the suspension on different trips, a user may determine whether the pothole is getting larger or deeper or whether it has been repaired or not. z0 The trip test may be triggered by the application of a particular preset magnitude impulsive load. The test may further require that the location of the vehicle be ascertainable with precision. This may be accomplished using locating means such as GPS devices linked to the system. Upon triggering the trip test, the system may begin to record the performance of the suspension and the position of the vehicle when the test was triggered. 25 Suitably, the method of the present invention may be utilised to collect and analyse data in order to log the performance of the suspension of a vehicle. Individual components of the suspension may be tested or groups of components may be tested. The system allows the logging of information relating to the dynamic effect of impulsive loads applied to suspensions and the compliance of the suspension to parameters adapted to ascertain the 30 effectiveness of the suspension in dampening the impulsive load applied.

8 In a further form, the present invention resides in a method for logging the performance of a vehicle suspension system by testing dynamic performance of at least one vehicle suspension system component, the method including the steps of: a. Measuring the dynamic excursion of mass of an impulsive load with an electronic 5 weighing system in response to a unit impulsive load, wherein the electronic weighing system is mounted onboard the vehicle and monitors the at least one suspension system component, and b. Measuring an oscillation frequency of said at least one vehicle suspension system component in response to said unit impulsive load, and 0 c. Determining the damping ratio of the at least one vehicle suspension system component using the dynamic excursions of mass, and the maximum oscillation frequency of the at least one suspension system component wherein the electronic weighing system mounted on board the vehicle includes at least one load measuring element associated with one or more vehicle suspension system components, .5 an electronic data log to receive information from all load measuring elements on the vehicle, the performance of the vehicle suspension system being logged over a known road section and comparing the dynamic excursion of mass of an impulsive load from each load measuring element. A further feature of the system is the ability to use the electronic data to capture an ZO electronic signature or electronic fingerprint of each transducer or load cell connected either individually or collectively to each smart-amp so that each vehicle can be monitored for tampering as well as accuracy. This is done by using the data collected during a trip test and comparing the varying dynamic loads or outputs from each system or channel. 25 When operated according to this embodiment, the data log will record if the calibration of the system has been changed or tampered with in some way as to either decrease or increase the output for a known load. Tampering with the transducers/load cells causes the displayed weight to change accordingly. The purpose of tampering is reduce costs or increase revenue accordingly. 30 The dynamic data can be captured at random or at specific times and at a specific position/s and compared with the data acquired from a set of test results at time of calibration 9 when a known load is driven over a known section of road and the dynamic data is captured at that time as the original reference data for each system or vehicle accordingly. Another unique feature of the system is the raw-data output which is used for both fault finding and for tamper evidentiary purposes and which is integrated into the collected 5 dynamic data output. The electronic data log typically includes a timepiece having time and date information. The timepiece will normally be connected to the system and will maintain the time and date, once initialised. The timepiece may be embedded in the system of the present invention but may be a separate system. 0 The electronic data log will preferably record an installation timestamp with corresponding time identifier at the initialisation of the electronic weighing system. The electronic data log will then preferably update or record the timestamp in the electronic data log against the corresponding raw data using the date and time information from the timepiece and also increments the time identifier, whenever the time or date of the electronic .5 weighing system is changed. The system automatically records any change in the system date and time using an incrementing numeric sequence which is also time/date stamped recording the time and date of the change. The timestamp typically includes both date and time data. 20 The time identifier stored in the raw data preferably increments numerically upon a change being made. The electronic data log preferably stores all information from each load measuring element in a raw data form with corresponding timestamp data and stores the time identifier whenever the time or date of the electronic weighing system is changed. Therefore, the raw 25 data will normally be stored and will typically be flagged with timestamp and time identifier data whenever a change is made. As the electronic weighing system includes multiple load measuring elements, the electronic weighing system may store information from each load measuring element separately with the timestamp being updated and the time identifier incremented in the 30 electronic data log for each load measuring element separately. Alternatively, the timestamp may be updated and the time identifier incremented in the electronic data log whenever information from any load measuring element is changed.

10 The electronic data log will also preferably include calibration information generated when the electronic weighing system is calibrated. This information will then typically be stored in the electronic data log by recording an initial calibration timestamp with corresponding time identifier at the initial calibration of the electronic weighing system. The 5 system will also preferably update the calibration timestamp and increments the time identifier whenever the calibration information is changed. Preferably, the time identifier increments numerically upon a change being made. The electronic data log stores all information from the electronic weighing system in a raw form with corresponding timestamp data and updates the calibration timestamp and 0 increments the time identifier whenever the calibration data of the electronic weighing system is changed. As with the time data, the calibration timestamp may be updated and the time identifier incremented in the electronic data log for each load measuring element separately or alternatively, the calibration timestamp may be updated and the time identifier incremented in 5 the electronic data log whenever the calibration information is changed for any of the load measuring elements. Brief Description of the Drawings. Various embodiments of the invention will be described with reference to the following drawings, in which: 20 Figure 1 is a schematic illustration of a typical installation of an electronic weighing system to an air suspension on an articulated vehicle such as a truck and trailer according to an embodiment of the invention. Figure 2 is a schematic illustration of a typical installation of a system according to an aspect of the present invention on an articulated vehicle such as a truck and trailer. 25 Figure 3 is a graphical representation of a test signal returned during a step test conducted using the system according to an aspect of the present invention. Figure 4 is a graphical representation of a test signal returned during a bump test conducted using the system according to an aspect of the present invention. Figure 5 is a graphical representation of the absolute value of the test signal 30 returned during a bump test plotted against time conducted using the system according to an aspect of the present invention.

11 Figure 6 is a Fourier plot of the frequencies present in a trailer axle group's dynamic mass signal returned during testing conducted using the system according to an aspect of the present invention. Figure 7 is a schematic block diagram of a system of the invention shown coupled to 5 other components for facilitating the downloading of data from the system of the invention. Figure 8 is a schematic block diagram of a system of the invention shown coupled to other components for facilitating the downloading of data from the system of the invention. Figure 9 is a detailed block diagram of the system of the invention illustrated in schematic form in Figures 7 and 8. 0 Detailed Description of the Invention. According to an aspect of the invention, a method for logging the performance of a vehicle suspension system in reaction to impulsive loads applied thereto is provided. Generally, trucks and trailers and other heavy haulage vehicles are equipped with self levelling suspension systems. The systems are designed to compensate for changes in the 5 load by modifying the springing or dynamic characteristics of the suspension so that the vehicle(s), always remain approximately the same height off the road, whether empty, partially loaded, or fully loaded. The systems are designed to ensure that, even when the vehicle is fully laden, the full travel of the suspension system is available for absorbing bumps. Other related effects are 20 things such as the headlights are kept in proper focusing alignment, whatever the distribution of the load. Any form of self-leveling is generally operated by one or more load-sensing devices which measure the vertical distance between, for example the trailer bed and the suspension arm. The greater the load, the smaller this distance tends to become. An initial variation in 25 the distance operates a valve which controls the height-adjusting system. Usually, height adjustment takes place at both ends of vehicle, and in particular generally takes place at each axle or group of axles. Air suspensions are relatively simple in principle. Collapsible, pressurized air containers take the place of conventional springs or shock absorbers; the upward movement 30 of the wheeland the downward movement of the body or the load carrying element of the vehicle in response to a load reduces the volume of the air spring, raising its pressure, so that it tries to extend itself again. If the air spring is inflated more, thus increasing its internal 12 pressure it can carry a heavier load before contracting to a given height. A height-control valve connects the air spring to a high-pressure air reservoir so that when the load is increased the pressure in the air springs is increased in direct proportion to the increased load, and pressure is released through the valve to the atmosphere in direct proportion to the decreased 5 load when the load is reduced. Air suspensions generally also comprise dampers, often referred to as "shock absorbers". Dampers are designed to damp out vibrations so that the suspension does not continuously bounce up and down in response to an impulsive load. The purpose of dampers is to reduce oscillation by absorption of energy stored in the suspension. A damper may be 0 single action design where damping is only controlled in the one direction or, be a double action design in which damping is controlled in both directions. A typical installation of the components of an electronic weighing system to an air suspension on an articulated vehicle such as a truck and trailer, which are also used according to the method of the present invention, is illustrated in Figure 1. 5 In order to control the air suspension system, the system has a meter 11 connected to a power supply 12 for the system usually including a battery 14. The meter 11 is also associated with a data transmitter/receiver 13 which is capable of transmitting data which is captured by the system to a remote location and receiving data and/or commands from a remote source. An example of a remote interrogation unit 15 is also illustrated in Figure 1. !0 This unit is adapted for use to query the meter 11 onboard the truck when the truck is moving. Generally, radio frequency waves are used as a carrier signal to accomplish the data transfer. The system also has at least one and generally more than one smart amplifier 16 each individually associated with air pressure transducer/s (APT) 17, or load cell/s or combinations of these items, to acquire information regarding the gross and nett weights of the vehicle. 25 Each pressure transducer 17 is associated with a component of the vehicle suspension. Generally, each APT 17 is associated with an air spring which is associated with an axle. Each APT 17 provides feedback to the meter 11 regarding the response of the suspension to an impulsive load by measuring the dynamic excursions of mass generated by the movement of the suspension. 30 As stated above, each axle is generally provided with an APT 17 so that the dynamic excursions of mass generated by the movement at each axle in response to an impulsive load may be monitored. The meter 11 and power module 12 are generally located in the truck or 13 prime mover of the vehicle. These components are directly connected to the each APT 17 associated with the truck axles via a smart amplifier 16. The APT's 17 and the associated smart amplifiers 16 which monitor the trailer axles are connected to the meter 11 and power module 12 on the truck using a quick release 5 connector 18 so that different trailer may be connected to the one prime mover without loss of monitoring functions. Providing the system with a handheld remote transceiver 19 allows the vehicle operator to remain safe distance from the vehicle while the vehicle is being loaded and still monitor the weights displayed on the remote receiver 19. Examples of some of the 0 information which may be collected include gross weight, net weight, load collection and delivery, front end weight, rear end weight, weight distribution, mass management and suspension compliance testing, as well as the condition of a section of a road. The schematic layout of the components of the suspension system and electronic weighing system which is used to implement the method according to the present invention is .5 illustrated in Figure 2. The truck 21 and trailer 22 are shown with smart amplifiers 16 in place. Each smart amplifier 16 is associated with the in-cab hardware which allows a driver to monitor the performance of the suspension system of the truck and trailer combination, as well as the condition of any particular section of a road over which they are driving. 20 The smart amplifiers 16 are connected to a data logger 23. The data logger 23 is responsible for capturing and collating all of the information transmitted from the smart amplifiers 16 and the associated APT's. The data logger 23 is in turn associated with a computer 24 which is responsible for the use of the raw information collected to create useable information regarding the 25 parameters of the suspensions which are to be monitored or tested, , as well as the condition of any particular section of a road over which the data was collected. The system is also provided with a means to transmit and/or receive data or commands to and from a remote location 25, together with a locating means such as a GPS locator 26. The analysis of the information collected may take place at a remote location and the results transmitted back to 30 the vehicle, or to any other location for recording purposes or for further analysis, if so desired. In use, the system collects weight information from air pressure transducers 17 connected to air bag suspensions, and/or load cells mounted on the vehicle. The information 14 is then sent to the meter 11 where it is displayed in kilograms of weight applied at each individual axle or group of axles, as well as total weights. This allows the operator to check the weights on each axle group being used, as well as the axle group combinations and total weights as required on a display associated with the meter 11. 5 All information is date and time stamped and can be downloaded to a laptop 24 or a printer 27 in order to produce a hard copy on demand. All data is stored in an associated data log 23 which cannot be deleted without a specific set of instructions (and password) from the operator and all such actions being recorded and time/date stamped, accordingly.. The applicants have subjected the system and method to testing and analysis of the air 0 suspension of a newly constructed, 34 tonne, four-axle trailer. The analysis is compared with the European Union (EU) requirements for "road-friendly suspensions" on heavy vehicles. Feasibility of determining road-friendliness of air suspensions for heavy vehicles without recourse to laboratory or workshop facilities was also explored. The Truck & Trailer Test Rig 15 The truck was a standard KENWORTH* prime mover with air suspension on the drive axles coupled to a 4-axle trailer with air suspension. This is an innovative vehicle which meets all but one of the 20 Performance Based Standards (PBS) as proposed currently by the National Road Transport Commission (NRTC) specifications. The trailer was built by O'Phee Trailers and the combination is owned and operated by 20 a commercial carrying service. The truck/trailer combination has been on the road since mid February 2003 operating under permit. One of the conditions of the permit was that the vehicle was to be monitored for mass and position. The Gross Combination Masses (GCM) permitted is dependant on the position of the combination test rig. When the freight task is general freight/general access the GCM is not to exceed 42.5 tonne and which is described as 25 General Mass Limits (GML). When the GCM is not to exceed 50 tonne on a particular route between Acacia ridge and Lytton in Brisbane it is described as Higher Mass Limits (HML) access. The combination rig was tracked using Global Positioning System (GPS) position fixes from a C-Track GPS reporting system relayed back to a base station at the premises of 30 Digicore Pty Ltd, a third party service provider which compiled and stored the data. The C Track system reports every hour via a mobile phone link. The report contains the position of 15 the vehicle at various intervals on a real time basis. The prime mover was equipped, before this trial, with the GPS reporting system for fleet management purposes. Mass data from the drive axles of the prime mover and the trailer group is measured indirectly, but proportional to, air pressure in the high pressure air lines to the air suspension. 5 Air pressure is converted to a mass signal by a mass measurement system which sends the mass signals to the C-Track system as well as displaying the mass of the prime mover and the trailer on a display in the cabin. For the trailer, 40kg increments have been assigned to the digital mass measurement by the mass measurement system. The mass on the prime-mover is determined by the mass measurement system apportioning a mass value to the steer axle and 0 adding this to the measured value of air pressure on the drive group axle air line, proportional to the mass on that group. It is cheaper to instrument air suspensions than steel suspensions. To contain capital outlay, only the drive & trailer axle groups were instrumented and so the steer axle was not instrumented to measure mass. However, the geometry of the combination ensured a fairly [5 constant mass on the steer axle. The trailer has a YORK* control system which raises the front axle when the trailer is empty and drops the axle when a load is on board. For the purpose of the testing, a container with freight weighing approximately 11 tonne was loaded onto the trailer. The Tests Applied 20 The step test The yard of the freight operator presented an ideal opportunity to replicate the EU step test. The EU test uses an 80mm step down to create a negative step input to the vehicle suspension for purposes of determining damping ratio and fundamental frequency of axle-to /body bounce. 25 A new warehouse was being built in the yard of the freight operator and the slab was finished, awaiting the superstructure. This slab was 65mm above the surrounding surface of the yard manoeuvring apron. For one series of tests, the combination test rig was driven off the warehouse slab onto the apron at approximately 5km/h. The bump test 30 A second series of tests was performed by driving the combination test rig over a 50mm nominal diameter pipe at approximately 5km/h. The pipe had a bar welded to either 16 end to prevent rotation as the tyres moved over it. The pipe provided an approximation to a positive impulse signal applied to the suspension of the combination. The on-road test A final test was performed by driving the combination test rig over some roads near 5 the freight depot. The variation in the mass signal was recorded as the combination test rig travelled along these designated normal, uneven roads at speeds up to 60km/h. The RESULTS The step test The step test results plotted in Figure 3 show that the signal is varying slowly and 0 gives a shape that could not be analysed easily/meaningfully. Figure 3 shows the test signal as measured for the first 2 axles, the first axle signal on the left 40 and the entirety of the signal on the right (from 2.25 s to beyond 4.92s) is from the second axle. The other 2 axles produced a similar shape to axle 1 and have not been included for brevity. The bump test 5 The bump test yielded data that lent itself to more meaningful analysis and this data is shown in Figure 4. The three signals caused by the tyres from the 2 nd, 3 rd and 4 th axles travelling over the pipe are shown in the Figure from left to right (41, 42, 43) respectively. The second axle created the first excursion on the left of the graph. The signal generated by the first axle perturbation is not plotted here as it was similar to the two caused Z0 by axles 3 and 4, shown as the other two positive excursions in Figure 4. The on-road test The variation in the mass signal from the trailer axle group was of primary interest for this evaluation. A sample of how the data appears in hexadecimal format, this example from the on-road test appears below. 25 89 8887 868483 81 0002040709 OC GE 2A 02050709 GB GC GD GD GD GD OD GD GD GD OC OB 09 07 05 03 01 00 82 84 86 89 8B 8D 8F 88 81 83 85 86 87 89 89 8A 8B 8B 8B 8B 8B 8B 8B 8B 8B 8B 8A 898786848200020407 GA OD 23020508 GA OC GD GD OE GD OD GD GD GD GD GD OC OC GA 08 06 04 02 00 82 85 87 8A 8C 8E 80 82 84 85 87 89 8A 30 8B8B8C8C8C8C8C8C8C8B8A89888785 83 81 000305080B0E2702050709 GA GA GA GA GA GA GA 09 09 09 07 06 04 02 00 81 83 86 88 8B 8D 8F F4 82 84 85 87 89 89 8A 8A 8B 8B 8B 8B 8B 8B 8B 8A 8988 87868483 81000205 08 GA GD OF 260203 17 05 060707070707 07070706 05 04 0200 81 84 86 88 8A 8D 8F 84 81 83 85 86 88 89 8B 8C 8C 8D 8D 8D 8D 8D 8D 8D 8D 8D 8C 8B 89 88 86 84 82 00 01 04 06 09 OB OE 24 02 0406 07090909 09090909 0908 08 0605 03 00 81 83 86 88 8B 8D 8F F6 82 83 85 8688 89 8A 8B 8B 8B 8B 8B 8B 8B 8B 8B 8B 8A 888785 84820001040609 OC OE ID 5 0204050607070707070707070706050403010081 83 85 87898B8D8FF3 81 83 85 8687 89 89 8A 8A 8A 8A 8A 8A 8A 8A 8A 898886 85 83 820002040609 OBOE OE 0204 05 0708 08 090908 08 08 08 070604020081 8486 89 8B 8D 8F EO 81 83 85 86 87 88 89 89 89 89 89 89 89 89 89 88 87 86 85 83 820001 03 05 08 GA OD F4 020406 0809OAOBOBOAOAOAOAOA0907050301 818385888A8C8EE481 83848585 0 868686868686868686858584838281 000102040507090B0D0F16020405 07 08 09 09090908 08 08 07060403 01 81 83 85 87 8A 8C 8E 85 81 83 84 85 86 87 88 88 88 88 88 88 88 88 88 88 88 87 86 85 84 82 8100 0103 05 07 09 0C 0E OF 35 01 020304 04040404040403 03 02000082848688 8A 8C 8E 8F 8B 81 83 8485 8788 88 8989 89 89 89 89 89 89 89 89 88 88 87 8685 83 82000002040608 OA GC OE IC 01 030404 L5 05 05 05 04 05 05 04 04 03 02 00 81 83 85 87 89 8B 8D 8F F7 81 83 84 85 87 88 89 8A 8A 8A 8A 8B 8B 8B 8B OF B8 The data from the tests was converted and a plot of the variations in the dynamic mass induced by the dynamic forces on the combination was produced as Figure 6 as a 20 Fourier Plot of the frequencies present in the captured and recorded dynamic mass signals. Analysis The step test The step test did not yield any data that could be analysed in a meaningful way. It is noted that the EU test differs from the step test conducted in that it is usually conducted at 25 much a higher speed than those used for this testing, it is done for one axle only and the drop is 80mm, not 65mm as used for this testing. The applicants surmise that the effect of the air lines equalising the pressure differential between the air bags on differing axles caused the signal to behave in the manner shown in Figure 3, particularly for axle 2. It was thought that the 3 axles were restraining the first axle in the vertical plane as it went over the step but 30 when the second axle encountered the step the applicants thought that that was the point of equilibrium of the axle group and the group then teetered like a see-saw, giving the resultant 18 aberrant signal. The applicants also surmise that this was why the EU test was performed with only one axle and at relatively higher speeds. The bump test By taking the absolute values of the data from the first perturbation in Figure 4, that 5 is, the first and third excursions of the mass signal, the damping ratio (Q.) may be determined using the formula: = 6/ I (62 + (27C)2) 0 where 5 is the standard logarithmic decrement given by the following: 5 = In A, A2) and AI = amplitude of the first peak 44 in the plot of the absolute value of the response and

A

2 = amplitude of the third peak 45 in the plot of the absolute value of the response. t5 From Figure 5, it can be seen that the value of A 1 = 6 and A 2 = 1. It is noted that these values are the closest approximation to the actual values measured by the mass measurement system given the approximately 1000 digitisation steps over the measurement range of 40T: (40000kg/1000 = 40kg increments). Substituting the measured values of A 1 and A 2 yields a damping ratio (C) of 0.27 or 20 27%, allowing for the error described above. The EU Standard is 20% or greater so it can be seen that this trailer meets the EU Standard for "road-friendly suspension' damping. Further, this exercise shows that, by using a simple test of driving over a 50mm pipe and analysing the data provided by the on-board mass measurement system, the damping ratio may be determined by simple calculation. 25 The on-road test By subjecting the data from the on road test to Fourier analysis, the system is able to determine the trailer's body-to-axle-group frequencies induced by the dynamic forces on the combination. For this analysis, it was assumed that the dynamic mass signals derived from driving the vehicle on normal roads approximated to a random signal. Fourier analysis of an 30 output, or derived, signal after it has been generated from a random input signal of uniform 19 amplitude to any system allows determination of the transfer function of the system as expressed by the frequencies present in the dynamic excursions of mass output signals. The plot illustrated in Figure 6 is a Fast Fourier Transform (FFT) that is, by definition, lumpy and does not yield pure and clean plots on the magnitude axis. Even allowing for the 5 overall noise created by the FFT process, it can be seen that the greatest frequency magnitude 46 present in the FFT of the on-road signal is that of 1.5 Hz - 2 Hz. Given that the EU standard for body bounce is < 2.0 Hz, it is statistically probable that this parameter is met by the suspension tested and reflected on this plot. It is to be noted that some lower frequencies appear to be present and that there are greater magnitude frequencies at approx. 4 Hz, 8 Hz 0 and 15 Hz. Axle hop appears to be the explanation for the 15Hz signal. Further research is needed for the 4 & 8 Hz signals. Figure 7 shows an onboard mass measurement weighing system 30 of the invention coupled to an on-board personal computer (OBPC) 31, OBPC 31 is connected to an RF transmitter 32. Transmitter 32 allows data from the system 30 to be downloaded via a radio .5 link. A printer 32 is connected to the OBPC 31. A docking station 33 allows a host computer 34 to be coupled to the OBPC 31 or devices other than a computer 34 to be connected to OBPC 31. Computer 34 may download data from the system 30. Figure 8 shows a block diagram of an alternative way to that of figure 7 in which a system 30 may be coupled to other components to allow data to be downloaded from the 0 system 30. A serial memory unit (SMU) 40 is coupled to the system 30. A printer 41 and various communication devices 42 are connected to SMU 40. An on-board personal computer (OBPC) 43 is connected to the SMU 40 and this OBPC 43 is coupled to an RF transmitter 44 and a docking station 45. The docking station 45 allows a host computer 46 or other devices to be coupled to the OBPC 43 for downloading data. A memory unit 47 may be 25 coupled to the computer 46 to provide for data downloaded from the system 30 to be backed up in case of failure of the OBPC 43. The AAU illustrated in box 47 with an additional SMU, provides additional data back-up capabilities at the same time providing additional serial data ports to connect to various peripheral devices which are used by various operators of this system in various 30 applications or end uses. The SMU/AAU 47 is also used to store the data which is collected when performing the tests.

20 Figure 9 is a detailed block diagram of the system of the invention illustrated in schematic form in Figures 7 and 8. The system of the present invention also provides the ability to use the electronic data to capture an electronic signature or electronic fingerprint of each transducer or load cell 5 connected either individually or collectively to each of the smart amplifiers 16 so that each vehicle can be monitored for tampering as well as accuracy. This is done by using the data collected during an on-road test and comparing the varying dynamic excursions of mass or dynamic loads or outputs from each system or channel and recording same. 0 The dynamic data can be captured at random or at specific times and at a specific position/s and compared with the data acquired from a set of test results at time of calibration when a known load is driven over a known section of road and the dynamic data is captured at that time as the original reference data for each system or vehicle, accordingly. Another unique feature of the system is the raw-data output which is used for both .5 fault finding and for tamper evidentiary purposes and is integrated into the dynamic data output as follows. After the system is installed and the various software functions are activated , then the Time and Date is set and the system records this as TI and attaches a date stamp to it e.g. 13 th January 2008 is attached as 13/01/08 OR it can be attached as 01/13/08, depending on the 20 way in which various countries express the date. If for some reason the date, or the time, or both are changed the system automatically increments this change in an incrementing numeric sequence which is also time/date stamped, as follows. If time and/or date is changed the internal security system displays T2 15/05/08 if the change was done on May 15 th 2008. 25 Subsequent changes are numerical incremented and date stamped, accordingly. So, after six changes, the last one being on 19/08/08 the secure data for time/date displays as , T6 19/08/08, or as T6 08/19/08. Similarly, after initial installation the unit is calibrated and the secure data for calibration will display as Cl 13/01/08 and, if the system has been tampered with or re 30 calibrated for various reasons the unit will display C2 12/03/08, say, then C3 14/06/08 , say, and so on, each time the calibration is changed.

21 The Time/Date and the Calibrate functions are independent of one another but increment numerically with a time/date stamp as and when either one is changed. A typical 3 channel system for a B-Double is as follows and shows the secure data feature. 5 22 CHEK-WAY LOAD REPORT * TYPICAL B. TRAIN (3 channels) VEHICLE ID 22311 * METER I.D. Prime Mover & Both Trailers A24187 B24198 C24176 SECURE T-00 111202 C-01 111202 * SECURITY DATA PRINT DATE 17/03/2003 1654 DATE TIME CHN DATA TYPE * Date & Time of report with each channel in =--- Nett mode to show PAYLOAD. 17/03/2003 1654 AN +18390 CHNWGT B N +09200 CHN WGT Weight is positive (+) so no tare offsets. C N +15600 CHN WGT ABC +43190 CHN TOT END * END OF DOCKET WITH SPACE FOR SIGNATURE CHEK-WAY DATALOG REPORT * SUMMARY OF ALL LOAD REPORTS VEHICLE ID 22311 * SAME ID. 's in combination with no changes in A24187 B24198 C24176 SECURITY SECURE T-00 111202 C-01 111202 PRINT DATE 17/03/2003 1654 DATE TIME CHN DATA TYPE 11/12/2002 1527 A N -00000 CHN WGT * FIRST LOAD IN NETT WITH TWO CHANNELS B N -00018 CHN WGT EMPTY E Value shows SMALL TARE SHIFT 1530 A N +17018 CHN WGT * LOADED SHOWING NETT PAYLOAD B N +16960 CHN WGT 14/03/2003 1020 C 24176 ID-CONN * B-TRAIN combination assembled showing I.D. A 24187 ID-CONN of channels and position in the combination B 24198 ID-CONN 1052 A G +18848 CHN WGT * UNIT LOADED IN GROSS MODE showing B G +09790 CHN WGT weights on each unit C G +16500 CHN WGT 17/03/2003 1648 AG +18890 CHN WGT * UNIT LOADED IN GROSS MODE B G +09790 CHN WGT C G +16500 CHN WGT 1648 A N +18390 CHN WGT UNIT LOADED IN NETT MODE B N +09190 CHN WGT -- driver selectable C N +15600 CHN WGT END * END OF DOCKET WITH SPACE FOR

SIGNATURE

23 RAW DATA TEST * PRINTOUT of each vehicle's individual signatures 17/03/2003 CHEK-WAY 22311 * METER I.D. #CW-DDC V2.08-A3 * Software Version ID 24187 * This list of RAW DATA shows the unique status of TIME = 17.47 all channels in combination, at any point in time. It allows the investigator to trouble shoot the system CHN EPTY CAL-No and to check for any and all tampering which is A 0873 030 1 B6 displayed each time the RAW DATA@ is either viewed on the screen of the CHEK-WAY@ meter XCIT REGV LINE or "printed out" via the CHEK-WAY@ system 3329 2605 2704 serial port. GRP1 GRP2 TEMP 2885 4095 2456 ID 24198 TIME = 17.47 CHN EPTY CAL-No B 0052 02BB3A XCIT REGV LINE 3354 2603 2684 GRPI GRP2 TEMP 2703 0727 2461 ID 24176 TIME = 17.47 CHN EPTY CAL-No C 0044 O EA40 XCIT REGV LINE 3360 2632 2695 GRPI GRP2 TEMP 4095 4095 2463 ID 24176 TIME = 17.48 CHN EPTY CAL-No C 0044 OIEA40 XCIT REGV LINE 3360 2632 2696 GRPI GRP2 TEMP 4095 4095 2464 24 CHEK-WAY LOAD REPORT * Another LOAD REPORT at a different time. VEHICLE ID 22311 * VEHICLE/METER ID. A24187 B24198 C24176 CHANNEL I.D.'s. SECURE T-01 180303 C-01 111202 * SECURITY -NOTE changes to TIME SECURITY PRINT DATE 18/03/2003 2149 FLAG (no calibration change) DATE changed to To 18/3/2003 (T-0 now T-01) and TIME changed DATE TIME CHN DATA TYPE to 2149 hours. 18/03/2003 2149 AN +12390 CHNWGT BN +07530 CHNWGT C N +15600 CHNWGT ABC +35520 CHN TOT END CHEK-WAY LOAD REPORT * LOAD REPORT after additional changes. VEHICLE ID 22311 A24187 B24198 C24176 SECURE T-03 170303 C-01 111202 * NOTE CHANGE to TIME SECURITY FLAG PRINT DATE 17/03/2003 1750 time/date has been changed twice (T-01 now T-03). N.B. date field has been changed back to 17/03/03 DATE TIME CHN DATA TYPE and TIME changed back to 1750 hours. 17/03/2003 1750 AN +12330 CHNWGT BN +07530 CHNWGT CN +15600 CHNWGT ABC +35460 CHN TOT END CHEK-WAY LOAD REPORT * Another LOAD REPORT after changes made above. VEHICLE ID 22311 A24187 B24198 C24176 SECURE T-03 170303 C-01 111202 * SECURITY data is the same. PRINT DATE 17/03/2003 1751 DATE TIME CHN DATA TYPE 17/03/2003 1751 AG +12830 CHNWGT BG +08130 CHN WGT CG +16500 CHN WGT ABC +37460 CHLN TOT

END

25 CHEK-WAY LOAD REPORT * Another LOAD REPORT after the SECURITY changes. VEHICLE ID 22311 * DRIVER changed his time/date clock for some A2487 B24198 C24176 reason? SECURE T-03 170303 C-01 111202 PRINT DATE 17/03/2003 1751 DATE TIME CHN DATA TYPE 17/03/2003 1751 AG +22500 CHNWGT * Weight changed - new load (legitimate weights). B G +15948 CHN WGT C G +16500 CHN WGT ABC +54948 CHN TOT

END

26 RAW DATA TEST * RAW DATA report after the changes shows the 17103/2003 altered Date @ 17/03/2003 and the variations in the GRPl and GRP2 values as load changes. CHEK-WAY 22311 #CW-DDC V2.08-A3 ID 24187 TIME = 17.52 CHN EPTY CAL-No * No changes to CAL-No so no changes to the A 0873 0301B6 calibration factor of any channel - in other words weights are accurate, OR, the sane Values as per XCIT REGV LINE original calibration. 3329 2605 2703 GRPl GRP2 TEMP 4095 4095 2457 ID 24198 TIME = 17.52 CHN EPTY CAL-No B 0052 02BB3A XCIT REGV LINE 3354 2603 2684 GRP I GRP2 TEMP 1892 3776 2462 ID 24176 TIME = 17.52 CHN EPTY CAL-No C 0044 01EA40 XCIT REGV LINE 3360 2631 2694 GRP1 GRP2 TEMP 4095 4095 2465 27 CHEK-WAY LOAD REPORT * LOAD REPORT - note changes. VEHICLE ID 22311 * SECURITY - NOTE change to CALIBRATION A24187 B24198 C24176 FLAG (C-01 to C-02 on 17/03/03). SECURE T-03 170303 C-02 170303 PRINT DATE 17/03/2003 1754 DATE TIME CHN DATA TYPE 17/03/2003 1754 AG +20000 CHN WGT B G +15000 CHN WGT CG +16000 CHN WGT ABC +51000 CHN TOT

END

28 RAW DATA TEST * RAW DATA TEST after calibration factor altered 17/03/2003 -- channel A only. CHEK-WAY 22311 #CW-DDC V2.08-A3 ID 24187 * Single download of CH A only - selectable from TIME = 17.54 meter. * NOTE: change to CAL-No on each channel which CHN EPTY CAL-No has been altered. A 0873 02AA3F XCIT REGV LINE 3329 2605 2703 GRPI GRP2 TEMP * GRP 1 and GRP 2 have been maxed-out but the meter 4095 4095 2457 display shows less load on vehicle. This is a second --- .-.-.-.security flag which shows that meter is displaying less than the actual load. NOTE: Operator can not change the GRPI and GRP2 ID 24187 readings. TIME = 17.54 CHN EPTY CAL-No * Second download of RAW DATA. for all 3 channels. A 0873 02AA3F XCIT REGV LINE 3329 2605 2703 GRPI GRP2 TEMP * NOTE: GRPI and GRP2 readings. 4095 4095 2457 ID 24198 TIME = 17.55 CHN EPTY CAL-No * NOTE change to calibration numbers (CAL-No). B 0052 029086 XCIT REGV LINE 3354 2603 2684 GRPI GRP2 TEMP 1892 3776 2463 ID 24176 TIME = 17.55 CHN EPTY CAL-No C 004401DA8A XCIT REGV LINE 3361 2631 2695 GRPI GRP2 TEMP 4095 4095 2465 29 CHEK-WAY LOAD REPORT VEHICLE ID 22311 * SECURITY - NOTE change to calibration again A24187 B24198 C24176 (C-02 to C-03). SECURE T-03 170303 C-03 170303 PRINT DATE 1703/2003 1756 DATE TIME CHN DATA TYPE 17/03/2003 1756 AG +22500 CHN WGT * Channel weights returned to what they were at B G +15948 CHN WGT C-01 before they were reduced at C-02. CG +16500 CHNWGT ABC +54948 CHN TOT END RAW DATA TEST * RAW DATA TEST 17/03/2003 CHEK-WAY 22311 #CW-DDC V2.08-A3 ID 24187 TIME = 17.59 CHN EPTY CAL-No * NOTE - CAL-No values have been rernned A 0873 0301B6 to what they were (approx) at C-0 I before being reduced to show lesser gross weights. XCIT REGV LINE 3329 2605 2702 GRPI GRP2 TEMP 4095 4095 2458 ID 24198 TIME = 17.59 CHN EPTY CAL-No B 0052 02BBD6 XCIT REGV LINE 3354 2602 2683 GRPI GRP2 TEMP 1892 3776 2464 ID 24176 TIME = 17.59 CHN EPTY CAL-No C 0044 01EA40 XCIT REGV LINE 3360 2631 2694 GRP1 GRP2 TEMP 4095 4095 2466 30 Thus, any tampering with the system is monitored both by the electronic hardware or component and/or the software as well as the dynamic data output from each vehicle or channel and are linked one to the other, accordingly. In the present specification and claims, the word "comprising" and its derivatives 5 including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the 0 appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

Claims (16)

1. A method for logging the performance of a vehicle suspension system by testing dynamic performance of at least one vehicle suspension system component, the method including the steps of: a. measuring the dynamic excursion of mass of an impulsive load with an electronic weighing system in response to a unit impulsive load, wherein the electronic weighing system includes: at least one load measuring element mounted onboard the vehicle and associated with one or more vehicle suspension system components, and an electronic data log located onboard the vehicle to receive information from all load measuring elements on the vehicle and to monitor information from each at least one vehicle suspension system component, and b. measuring an oscillation frequency of said at least one vehicle suspension system component in response to said unit impulsive load utilising the electronic weighing system, c. determining the damping ratio of the at least one vehicle suspension system component using the measured dynamic excursion of mass, and the measured maximum oscillation frequency of the at least one vehicle suspension system component, d. attaching an identification code within the electronic data log onboard the vehicle to information measured or determined to allow the tracking of data within the electronic data log, wherein the identification code is automatically incremented when a change is made to the information, and e. comparing the dynamic excursions of mass of an impulsive load on and from at least one load measuring element, taken at a first time to the dynamic excursion of mass of said impulsive load from at least one load measuring element taken at a second time, wherein the performance of the vehicle suspension system is logged over a known road section at different times and by comparing the dynamic excursion of mass of an impulsive load from each load measuring element at the different times.

2. A method according to claim 1 wherein the electronic data log includes a timepiece having time and date information, the electronic data log recording an installation timestamp with corresponding time identifier at the initialisation of the electronic weighing system and updates the timestamp recorded in the electronic data log using the 32 timepiece and increments the time identifier, whenever the time or date of the electronic weighing system is changed.

3. A method according to claim 2 wherein the timestamp includes date and time data.

4. A method according to claim 2 wherein the time identifier increments numerically upon a change to the time or date of the electronic weighing system being made.

5. A method according to claim 2 wherein the electronic data log stores all information from each load measuring element in a raw form with corresponding timestamp data and stores the time identifier whenever the time or date of the electronic weighing system is changed.

6. A method according to claim 2 wherein the electronic weighing system includes multiple load measuring elements and the electronic weighing system stores information from each load measuring element separately and the timestamp is updated and the time identifier incremented in the electronic data log for each load measuring element separately.

7. A method according to claim 2 wherein the electronic weighing system includes multiple load measuring elements and the timestamp is updated and the time identifier incremented in the electronic data log whenever information from any load measuring element is changed.

8. A method according to claim 1 wherein the electronic data log includes calibration information when the electronic weighing system is calibrated, the electronic data log recording an initial calibration timestamp with corresponding time identifier at the initial calibration of the electronic weighing system and updates the calibration timestamp and increments the time identifier whenever the calibration information is changed.

9. A method according to claim 8 wherein the timestamp includes date and time data.

10. A method according to claim 8 wherein the time identifier increments numerically upon a change to the calibration information being made.

11. A method according to claim 8 wherein the electronic data log stores all information from electronic weighing system in a raw form with corresponding timestamp data and updates the calibration timestamp and increments the time identifier whenever the calibration data of the electronic weighing system is changed.

12. A method according to claim 8 wherein the electronic weighing system includes multiple load measuring elements and the electronic data log stores information from each load measuring element separately, the calibration timestamp being updated and the time 33 identifier incremented in the electronic data log for each load measuring element separately.

13. A method according to claim 8 wherein the electronic weighing system includes multiple load measuring elements, the calibration timestamp being updated and the time identifier incremented in the electronic data log whenever the calibration information is changed for any of the load measuring elements.

14. A method for logging the performance of a vehicle suspension system including the steps of. measuring the dynamic effect of an impulsive load with an electronic weighing system, wherein the electronic weighing system is mounted onboard the vehicle and includes an electronic data log, determining one or more parameters selected from a group consisting of the damping ratio of the suspension, the oscillation frequency of the suspension and the impact loading of the vehicle, and attaching an identification code within the electronic data log onboard the vehicle to information measured or determined to allow the tracking of data within the electronic data log, wherein the identification code is automatically incremented when a change is made to the information.

15. A method according to claim 8 wherein the calibration information includes raw data, the raw data including any one or more of the following types of data: a time or date, a channel calibration number, a excitation, regulated or line voltage, a group 1 or group 2 output, or operating temperature, wherein the electronic data log updates the calibration timestamp and increments the time identifier whenever the raw data information is changed on board the vehicle.

16. A method according to claim 15 wherein at least a date is uniquely recorded for each suspension system on the vehicle to which the at least one load measuring element is associated.