SE542495C2

SE542495C2 - Method and control unit for handling a varying load applied to a component

Info

Publication number: SE542495C2
Application number: SE1851154A
Authority: SE
Inventors: Anders Larsson; Erik Höckerdal; Henrik Svärd; Madeleine Ekström; Martin Karlsson; Oskar Leufven
Original assignee: Scania Cv Ab
Priority date: 2018-09-27
Filing date: 2018-09-27
Publication date: 2020-05-26
Also published as: DE112019004868T5; WO2020067958A1; SE1851154A1

Abstract

A method and a control unit for determining and handling a varying load being applied to a component are presented,the method includes:- determining a signal Srepresenting the varying load;- determining extreme values S, S,, Sfor the varying load signal S; - storing the extreme values S, S,, Sin a buffer memory;- determining that at least one closed cycle is included in the varying load signal S, the determining of each included closed cycle being based on three consecutive extreme values S, S, Sstored in the buffer memory;- determining at least one cycle representing value S, S,, Srelated to the at least one determined closed cycle, respectively;- storing the determined at least one cycle representing value S, S,, Sin at least one closed cycle data memory;- deleting at least one of the three consecutive extreme values S, S, Sof each determined closed cycle from the buffer memory; and- performing at least one action based on at least one cycle representing value S, S,, Sstored in the at least one closed cycle data memory.

Description

lO METHOD AND CONTROL UNIT FOR HANDLING A VARYING LOAD APPLIED TOA COMPONENT Technical field The present invention relates to handling a varying load being applied to acomponent, and in particular to a method and a control unit for handling such avarying load. The present invention also relates to a vehicle including the control unit.The present invention also relates to a computer program and a computer-readablemedium that implement the method according to the invention.

Background The following background description constitutes a description of the background tothe present invention, which does not, however, necessarily have to constitute prior art.

A large number of components, for example in a vehicle, experience a varyingload/stress being applied to it during operation. Such varying loads may be causedby a varying rotational speed and/or by a varying temperature of the component, oron at least one part of the component experiencing such varying loads. A varyingpressure or force acting on the component or at least one part of the component may also result in a varying component load/stress.

Such a varying load may affect the one or more materials being included in thecomponent and/or in the at least one part of the component. A varying load may forexample shorten the lifetime of the component and/or the at least one component part due to material fatigue.

As an example, compressor impellers, which may be included in turbochargersand/or charge air coolers of a vehicle, and turbine wheels, may experience varyingloads in the form of varying rotational speeds u) for the impellers and/or wheelsduring operation. Such a varying rotational speed u) results in greatly varying forcesacting on the component since the forces F depend on, i.e. is a function fof, thesquared rotational speed m2; F = f(w2). Thus, a significant change in the rotationalspeed u) results in a considerable change of the forces acting on the component, and thus also in a considerably varying load. Such varying loads may induce low cycle lO fatigue (LCF) damage of the component, such that there is a risk that at least one material of which the component is made/composed is damaged.

Corresponding material fatigue and/or damage may also result from varying loadsdue to varying temperatures and/or varying pressures acting on the component andits parts.

Thus, varying loads may cause fatigue and/or damages on components, that mayresult in component failure. Component failures are often very costly and annoying.For example, for a vehicle component, a component failure may force the vehicle offthe road, which probably causes delivery and/or driving schedule problems, and also causes extra service costs and inconvenience for the driver and/or passengers.

Therefore, it is important to keep components being affected by varying loads undercontrol, e.g. by providing material fatigue diagnostic and keeping track of the remaining lifetime of the components.

Brief description of the invention The conventional methods for estimating fatigue related problems resulting fromvarying loads are rather complex. The known methods are computationallydemanding and also requires extensive memory resources. The computational powerand/or the memory available for these computations may be restricted in manyapplications, e.g. in a vehicle implementation. Thus, the conventional methods aregenerally unsuitable for many practical implementations where material fatigue related problems may occur. lt is therefore an objective of the present invention to provide a method and a controlunit for handling varying loads being applied to components, such that the above- mentioned problems are at least partly solved.

According to an aspect of the present invention, this objective is achieved throughthe above-mentioned method for determining and handling a varying load beingapplied to a component; the method including: - determining a signal Sioad representing the varying load; lO - determining extreme values Sexii_1, Sexii_2, Sexig for the varying load signal Sieeii;- storing the extreme values Sexii_1, Sexii_2, Sexig in a buffer memory; - determining that at least one closed cycle is included in the varying load signal Sieeii,the determining of each included closed cycle being based on three consecutiveextreme values Sexii_ix-2, Sexii_ix-1, Sexig stored in the buffer memory; - determining at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii relatedto the at least one determined closed cycle, respectively; - storing the determined at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii in at least one closed cycle data memory; - deleting at least one of the three consecutive extreme values Sexii_ix-2, Sexii_ix-1, Sexigof each determined closed cycle from the buffer memory; and - performing at least one action based on at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii stored in the at least one closed cycle data memory.

Hereby, closed cycles in the varying load affecting the component are efficientlyidentified, and valuable information related to these closed cycles, i.e. the closedcycle representing values, are stored for further usage when performing the one ormore actions in reply to the varying load. Hereby, necessary measures/actions to beperformed may reliably be determined, such that the material fatigue due to thevarying loads may safely be counteracted.

For example, in order to provide a maximal output of an engine, it is important to beable to correctly define a maximally allowed rotational speed for a turbo compressorimpeller, without risking a failure of the turbo compressor, which could also lead toengine breakdown. When the herein described invention and its embodiments areutilized, the condition of the turbo compressor may be closely and reliablydetermined, wherefore the maximally allowed rotational speed for a turbo compressormay be set to a higher value than for conventional solutions. Hereby, the outputpower being possible for the engine to provide may be increased thanks to theincreased maximally allowed rotational speed for a turbo compressor, which makes itpossible for the turbo compressor to deliver a larger amount of air into the cylindersof the engine. lO Thus, by usage of the present invention, fact-based decisions related to thecomponents, such as e.g. a fact-based definition of a maximally allowed rotationalspeed for a turbo compressor, may be made. For example, if the compressorrotational speed of a group of vehicle does not vary very much, this group of vehiclemay have the maximally allowed rotational speed for a turbo compressor set to ahigher value than for another group for which the rotational speed varies more. Also,if it is determined that the damage rate for a certain component, e.g. a turbocompressor of a certain vehicle, is low, one or more parameters influencing howmuch the load on that component will vary, e.g. the maximally allowed rotationalspeed for a turbo compressor, may be set such that a higher degree of variations ofthe load is made possible.

By gathering information/data from a large number of components, such as dutycycle data from components of each vehicle in a vehicle fleet, the fleet managementand/or the owner will be able to learn from each and every component failure in theﬂeet. This gained information may thus be used for estimating risks for failures forother components in the ﬂeet, which considerably reduces the risk for componentfailure if taken into consideration when controlling the components and/or scheduling component service.

Also, the reliable identification of the closed cycles, and the storage of the valuablecycle representing values related to the closed cycles in the at least one closed cyclememory makes it possible to delete data related to one or more extreme valuespreviously being stored in the buffer memory. Hereby, a buffer memory of restrictedsize may be utilized for handling the varying loads according to the embodiments ofthe present invention. Therefore, the embodiments of the present invention mayeasily be implemented in a number of applications for which the available buffermemory is limited in size. ln a vehicle, for example, the buffer memory beingavailable for these calculation may be limited. The embodiments of the presentinvention may, however, easily be implemented in vehicle applications anyway, dueto the intelligent herein described signal processing and usage of the limited buffermemory and the closed cycle data memory. ln this document, extreme values are defined as values for a signal at one or more extreme points of the signal, i.e. in local maximum and/or minimum points of the lO signal. For a value to be a local maximum of a signal, the value of the signal at themoments both before, e.g. right before, and after, e.g. right after, the maximum valueis attained are lower than said value. For a value to be a local minimum of a signal,the value of the signal at the moments both before, e.g. right before, and after, e.g. right after, the minimum value is attained are higher than said value.

As is stated in the independent claims, a varying load is determined and handled bythe embodiments of the present invention. As is understood by a skilled person,handling of a varying load may include a large number of possible actions, decisionsand/or considerations being performed. Thus, handling of the varying load maycomprise essentially any usage of the cycle representing values, such as storing thevalues and/or using them as a basis for essentially any computations, calculations,analysis and/or decisions. One such decision made based on the cycle representingvalues may be that at least one action should be performed. Another decision madebased on the cycle representing values may be that at least one action should bedelayed and/or put on hold. Yet another decision made based on the cyclerepresenting values may be that no action should be performed. Also, by usage ofthe present invention and its embodiments, a greater knowledge of components, forexample of turbo compressors, may be gained by an efficient collection of data froma large number of individual components, for example from turbo compressors onboard a large number of vehicle individuals, e.g. in a vehicle fleet.

According to the present invention, the determining that at leastone closed cycle is included in the varying load signal Sioad includes: - determining a first difference ASeXiU between a first value SeXiLk-z and a secondvalue Sexigci of the three consecutive extreme values; - determining a second difference ASexiLz between a second value SeXiLk-i and a thirdvalue Sexig of the three consecutive extreme values; and - determining that the three consecutive extreme values SeXiLk-z, SexiLk-i, Sexigdefines a closed cycle if an absolute value of the second difference ASexiLz is greaterthan or equal to an absolute value of the first difference ASeXiU ; |ASeXir_2| 2 |ASeXir_1|.

Hereby, closed cycles included in the varying load signal Sioad are reliably and efficiently identified/determined. To reliably identify these closed cycles are important lO due to the possibly harmful effect such cycles may have on the components and/or component parts.

According to an embodiment of the present invention, the determining each of the atleast one cycle representing value Seyeie_i, Seyeie_a, Seyeie_ii includes one in thegroup of: - determining an average value Siiieeii for a determined closed cycle based on thefirst value Sexiga and the second value Sexig-i of the three consecutive extremevalues; Siiieeii = (Sexiga + Sexii_ix-i)/2; and a range value Sieiige for the determinedclosed cycle being equal to an absolute value of the determined first differenceASexir_1; Sreiige = |ASexir_1|; - determining an average value Siiieeii for a determined closed cycle based on the firstvalue Sexiga and the second value Sexig-i of the three consecutive extreme values;Smeeii = (Sexiga + Sexii_ix_1)/2; and a maximum value Siiiex for the determined closedcycle being equal a greatest value of the first value Sexiga and the second valueSexiga; Smex = max(Sexiga, Sexig-O; - determining an average value Siiieeii for a determined closed cycle based on the firstvalue Sexiga and the second value Sexig-i of the three consecutive extreme values;Smeeii = (Sexiga + Sexii_ix_1)/2; and a minimum value Siiiiii for the determined closedcycle being equal to a smallest value of the first value Sexiga and the second valueSexiga; Smiii = min(Sexir_|<-2, Sexig-O; - determining a maximum value Smex for a determined closed cycle () being equal to agreatest value of the first value Sexiga and the second value Sexii_ix-1 of the threeconsecutive extreme values; Siiiex = max(Sexiga, Sexii_ix-i); and a minimum value Smiiifor the determined closed cycle being equal to a smallest value of the first value Sexiga and the second value Sexig-i ; Siiiiii = min(Sexii_ixa, Sexii_ix_i).

Since a number of different values may be determined and used as cyclerepresenting values according to these embodiments, the method according to theembodiments of the present invention is flexible and may be applied on various typesof varying load signals Sieeii. Efficient utilization of the often limited memory resourcesof a control unit may be achieved by intelligent choices of representation values, e.g. by usage of the herein described average, range, minimum and/or maximum values. lO Hereby, storing of data in an approximate rain flow matrix/load matrix may be very efficiently performed.

According to an embodiment of the present invention, the deleting at least one of thethree consecutive stored extreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix includes one in thegroup of: - deleting a first value Sexii_ix-2 and a second value Sexii_i<-1 of the three consecutiveextreme values if more extreme values than the three consecutive stored extremevalues Sexii_i<-2, Sexii_i<-1, Sexii_k are stored in the buffer memory; - deleting a first value Sexii_ix-2 and a second value Sexii_i<-1 of the three consecutiveextreme values if an absolute value |ASiiiiiiei| of a difference between the first Sexii_1and a third Sexii_s extreme values in the buffer memory is smaller than a bufferthreshold value ASbufreLiii; |ASbuffer| < ASbufreLiii; and - deleting the first value Sexii_ix-2 of the three consecutive extreme values if three orless extreme values are stored in the buffer memory and an absolute value |ASbiiifei|of a difference between the first Sexii_1 and a third Sexii_s extreme values in the buffermemory is equal to or greater than a buffer threshold value ASbiiifeLiii; |ASbiiifei| 2 ASbufreLih _ Hereby, an intelligent deletion of values from the buffer memory is achieved, whichcarefully chooses values being related to identified closed cycles to be deleted fromthe buffer memory and stored in the closed cycle memory instead. Hereby, thelimited size of the buffer memory is carefully taken into consideration such that it does not affect handling of the varying loads acting on the components.

According to an embodiment of the present invention, the performing at least oneaction includes incrementing element values of a rain flow matrix Mieiiifiewcorresponding to the determined at least one cycle representing value Seyeie_i, Scycle_2, . . . , Scycle_n.

Hereby, the values/information/data related to the closed cycles of the varying loadsis saved in a format that preserves information about the duty cycle of the at leastone component, i.e. how the component is used. By saving the information in a rain flow matrix, computer memory is saved compared to individual storage of each cycle lO representing value, making the method useable in systems with limited memory, such as onboard computers and control systems in vehicles.

According to an embodiment of the present invention, the performing at least oneaction includes at least: - determining a value R representing the risk for failure based on a damage modelMdamage and on the at least one cycle representing value ScycieJ, Scycieg, Scyc|e_nstored in the at least one closed cycle data memory; - comparing the risk value R with a risk threshold value Rm; and - performing at least one action based on the comparison.

Hereby, a reliable evaluation of the risk for failure for the one or more componentsand/or its component parts is provided, which secures that the at least one actionchosen to be performed matches the determined risk.

According to an embodiment of the present invention, the determining of the risk forfailure representing value R includes: - determining at least one partial damage value Dpariaai; and - adding the at least one partial damage value Dpafiiai to a cumulative damage value Dcumulative.

To determine the risk for failure representing value R based on partial damage valuesDpariiai reduces the computational complexity for the determination. Also, based onpartial damage values Dpafiiai a point in time for a component failure and/orbreakdown may be predicted. For example, one or more extrapolations based on afirst order derivative of the partial damage values Dpafiiai, and possibly also based onhigher order derivatives of the partial damage values Dpariiai, being indicative of atrend for the component damage/fatigue, a point in time for a component failureand/or breakdown may be reliably predicted.

According to an embodiment of the present invention, the varying load originatesfrom at least one of: - a varying rotational speed w of at least one part of the component, wherein thevarying load signal Sioad at least includes rotational speed related values; - a varying temperature T of at least one part of the component, wherein the varying load signal Sioad at least includes temperature related values; lO - a varying torque Tq of one or more of an engine, a machine and anothercomponent providing the torque Tq, wherein the varying load signal Sioad at leastincludes torque related values; - a varying pressure P on at least one part of the component, wherein the varyingload signal Sioad at least includes pressure related values; and - a varying force F on at least one part of the component, wherein the varying loadsignal Sioad at least includes force related values.

Thus, the embodiments of the present invention may be used for handling varyingloads originating from various components and/or conditions, wherefore the embodiments may be generally used in many implementations.

According to an embodiment of the present invention, the varying load includes atleast one of: - a mechanical load; - a physical load; and - a thermic load.

Thus, various types of varying loads may be handled by usage of the embodiments of the present invention.

According to an aspect of the present invention, the component is affected by lowcycle fatigue (LCF) due to the varying load being applied to the component.

The embodiments of the present invention efficiently and reliably handle low cyclefatigue problems occurring in the components and/or component parts. Hereby, therisk for component failure and/or vehicle off road situations caused by such low cyclefatigue problems is considerably reduced.

According to an aspect of the present invention, the performing at least one actionincludes at least one in the group of: - predicting a component failure; - indicating to a driver that a component failure is to be expected; - indicating to an entity external from a vehicle in which the component is includedthat a component failure is to be expected; - pFOVldlng the aVefage Smean_1, Smean_2, ..., Smean_n and range Srange_1, Srange_2, ..., lO lO Sieiige_m values to an entity external from a vehicle in which the component isincluded; and - adjusting at least partly a control of the component such that a rate of damage forthe component is changed.

Hereby, suitable counter measures/actions being matched to the specific problemsrelated to the varying load may be chosen. Thus, varying loads are handled by theembodiments of the present invention. As is understood by a skilled person, handlingof a varying load may include a large number of possible actions, decisions and/orconsiderations being performed, of which the above mentioned actions, decisionsand/or considerations are only some examples. Thus, handling of the varying loadmay comprise essentially any usage of the cycle representing values, such as storingthe values and/or using them as a basis for essentially any computations,calculations, analysis and/or decisions, such as e.g. as basis for gathering statisticaldata. One such decision made based on the cycle representing values may be that atleast one action should be performed, e.g. at least one of the above-mentionedactions. Another decision made based on the cycle representing values may be thatat least one action should be delayed and/or put on hold. Yet another decision made based on the cycle representing values may be that no action should be performed.

According to an aspect of the present invention, a control unit arranged fordetermining and handling a varying load being applied to at least one part ofacomponent is presented.

The control unit is arranged for: - determining a signal Sieeii representing the varying load; - determining extreme values Sexii_1, Sexii_2, Sexii_ix for the varying load signal Sieeii;- storing the extreme values Sexii_1, Sexii_2, Sexii_k in a buffer memory; - determining that at least one closed cycle is included in the varying load signal Sieeii,the determining of each included closed cycle being based on three consecutiveextreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix stored in the buffer memory; - determining at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii relatedto the at least one determined closed cycle, respectively; - storing the determined at least one cycle representing value Seyeie_1, Seyeie_2, lO ll Scycie_n in at least one closed cycle data memory; - deleting at least one of the three consecutive extreme values SeXir_i<-2,SeXir_k-1, Sexigof each determined closed cycle from the buffer memory; and - performing at least one action based on the at least one cycle representing valueScycieJ, Scycieg, Scycie_n stored in the at least one closed cycle data memory.

According to an aspect of the present invention, the objective is achieved through a vehicle, e.g. a truck, a tractor, a bus and/or a car, including the control unit. lt will be appreciated that all the embodiments described for the method aspects ofthe invention are applicable also to the control unit and vehicle aspects of theinvention. Thus, all the embodiments described for the method aspects of theinvention may be performed by the control unit, which may also be a control device,i.e. a device. The control unit and its embodiments have advantages correspondingto the advantages mentioned above for the methods and their embodiments.

According to an aspect of the present invention, the above-mentioned computerprogram and computer-readable medium are configured to implement the methodand its embodiments described herein.

Brief list of figures Embodiments of the invention will be illustrated in more detail below, along with the enclosed drawings, where similar references are used for similar parts, and where: Figure 1 shows an example vehicle, in which embodiments of the present inventionmay be implemented, Figure 2 shows a flow chart for a method according to some embodiments of the present the invention, Figures 3a-d show flow charts for methods according to some embodiments of thepresent the invention, Figure 4 schematically illustrates a varying load signal, lO 12 Figure 5 shows a control unit, in which a method according to any one of the herein described embodiments may be implemented, and Figure 6 shows a flow chart for a method according to some embodiments of the present the invention.

Description of preferred embodiments Figure 1 schematically shows an exemplary heavy vehicle 100, such a heavy truck,which will be used to explain the herein presented embodiments. The presentinvention and its embodiments are, however, not limited to use in vehicles as theones shown in figure 1, but may also be used in other vehicles, such as in buses,cars, tractors, and may also be used in other implementations, i.e. in non-vehiclerelated applications. The present invention may thus be generally used on essentiallyany component experiencing a varying load, i.e. on such components being locatedboth onboard and offboard vehicles. For simplicity and pedagogical reasons,however, the present invention will herein mainly be described for one of its possible implementations, more specifically for a vehicle implementation.

A vehicle 100, as shown schematically in Figures 1, comprises a pair ofdrive wheels111, 112 and at least one other pair of wheels. The vehicle furthermore comprises adrivetrain configured to transfer a torque between at least one power source 101 andthe drive wheels 111, 112. The at least one power source 101 may include acombustion engine, at least one electrical machine, or a combination of these,implementing a so-called hybrid drive. The at least one power source 101 may, whenbeing a combustion engine, be provided with fuel from a fuel tank coupled to the atleast one power source. The power source 101 may also be provided with electrical energy by at least one battery coupled to the at least one power source.

The at least one power source 101 is for example in a customary fashion, via anoutput shaft 102 of the power source 101, connected to a clutch 106, and via theclutch also to a gearbox 103. The torque provided by the power source 101 isprovided to an input shaft 109 of the gearbox 103. A propeller shaft 107, connectedto an output shaft ofthe gearbox 103, drives the drive wheels 111, 112 via a centralgear 108, such as e.g. a customary differential, and drive shafts 104, 105 connectedwith the central gear 108. Also, one or more electrical machines may be arranged lO 13 essentially anywhere, as long as the produced torque is provided to one or more ofthe wheels, e.g. adjacent to one or more of the wheels, as is understood by a skilled person.

Exhaust gases produced by a combustion engine of the at least one power source101 are treated by an exhaust treatment system 150. The exhaust gases may be ledto the exhaust treatment system 150 through piping 151 being connected to theengine 101 via an exhaust manifold 152, the exhaust manifold 152 being arrangedfor receiving the exhaust gases from the engine and leading them to the piping 151.The exhaust treatment system 150 may include essentially any number ofcomponents, in essentially any configuration. Exhaust treatment system componentsmay e.g. include one or more filters, such as diesel particulate filters (DPFs), one ormore oxidation catalysts (DOCs), one or more selective catalytic reduction (SCR)catalysts, and/or one or more other components useful for treatment of the exhaust gases in order to reduce the harmful exhaust gas emissions from the engine 101.

A combustion engine 101 of the at least one power source 101 may be provided withair by a turbo compressor 153. The turbo compressor 153 is then arranged for beingdriven by the exhaust stream, and is arranged for providing compressed air into the combustion engine 101.

The air being provided to the combustion engine 101 may also pass through anintercooler/charge air cooler 154 in order to reduce an induction air heat resultingfrom the increased pressure caused by the turbo compressor 153, i.e. in order tolower the temperature of the air being pressed into the engine by the turbocompressor 153.

By usage of the turbo compressor 153 and the intercooler/charger air cooler 154, theoutput of the combustion engine 101 may be increased due to intake of a denser airinto the engine 101.

A number of these components may experience a varying load/stress being appliedto it during operation. The varying loads may result from a varying rotational speed,e.g. for the turbo compressor comprising at least one impeller, and/or may result froma varying temperature of the component, e.g. for the exhaust gas outlet manifold 152, the turbo compressor 153, the intercooler/charger air cooler 154 and/or one or more lO 14 of the components of the exhaust treatment system 150. Also, a varying pressureacting on the component or at least one part of the component may also result in avarying component load/stress, e.g. for the exhaust outlet manifold 152, the turbocompressor 153 and/or the intercooler/charger air cooler 154. These potential varyingloads may shorten the lifetime of the component due to material fatigue for thematerial of at least one part of the component, and may cause component failures,which can be very costly.

A control unit/device 160 may be arranged for determining and handling such avarying load, by including a first determination unit 161, a second determination unit162, a third storing unit 163, and a fourth determining unit 164, a fifth determining unit165, a sixth storing unit 166, a seventh deletion unit 167 and an eighth performanceunit 168, as is mentioned below. A control unit/device 160 may be connected to oneor more of the components that may experience the varying load/stress, e.g. to the atleast one power source 101, the exhaust manifold 152, the turbo compressor 153,the intercooler/charger air cooler 154 and/or the exhaust treatment system 150.

The control unit/device 160 and/or another control unit/device may further beconfigured for controlling one or more of the at least one power source 101, theclutch 106, the gearbox 103, and/or any other units/devices/entities of the vehicle.Generally, in figure 1, only the units/devices/entities of the vehicle useful forunderstanding the present invention are illustrated.

The vehicle 100 may further include one or more sensors 169, such as e.g. arotational speed sensor, a temperature sensor, a pressure sensor or another sensorproviding indications related to a varying load, located at suitable positions within thevehicle for detecting the varying loads/stresses, e.g. on or at the respective one ormore components experiencing these varying loads/stresses, such as on or at thepower source 101, the exhaust manifold 152, the turbo compressor 153, theintercooler/charger air cooler 154 and/or the exhaust treatment system 150. Thecontrol unit 160 may be connected to such sensors 169, either by a wired or a wireless connection.

The vehicle 100 may also include at least one input/output device 130 arranged for receiving an input from the driver and/or for providing information to the driver, as is lO described more in detail below. The at least one input/output device 130 may includeat least one screen, at least on lamp/light, at least one button, at least one knob, atleast one lever, at least one touch screen, or any other suitable input/output device.

The vehicle 100 may further include at least one communication device 170 arrangedfor communication with at least one offboard entity 190 external to the vehicle 100,such as e.g. a server, computer, or another device being arranged for performingcomputing and for communicating with the at least one onboard communicationdevice 170. The at least one communication device 170 may also be configured forreception of a positioning signal, such as e.g. a global positioning system (GPS) signal.

According to various embodiments of the present invention, the at least onecommunication device 170 may be essentially any device transferring information toand/or from the vehicle, and the at least one entity 190 external to the vehicle 100may be essentially any external entity communicating with the vehicle 100, i.e. withthe at least one communication device 170, for the transfer of the information toand/or from the vehicle. The at least one communication device 170 may at leastpartly include an entity configured for performing signal processing and/orcomputations, such as e.g. a control unit/device and/or a processor unit/device. Theat least one external entity 190 may e.g. be associated with, such as being includedin, an infrastructure entity and/or another vehicle. The at least one communicationdevice 170 may e.g. be a vehicle-to-vehicle (V2V) communication device, a vehicle-to-infrastructure (V2l) communication device, and/or a vehicle-to-everything (V2X)communication device, such that communication between the vehicle 100/170 andthe at least one external entity 190 is achieved/provided. The at least one externalentity may also provide a positioning signal.

Figure 2 shows a flow chart for a method for determining and handling a varying loadbeing applied to a component 150, 152, 153, 154, according to some embodimentsof the present invention. The method 200, and its embodiments, may be performedby an onboard control unit 160 e.g. included in a vehicle 100, as is explained in detailin this document. The method 200, and its embodiments, may also be performed at least partly by an offboard control unit being located essentially anywhere and being lO 16 connected/related/associated with at least one component experiencing a varying load/stress, as herein described. lt should be noted that the method steps illustrated in figure 2 and described hereindo not necessarily have to be executed in the order illustrated in figure 2. The stepsmay essentially be executed in any suitable order, as long as the physicalrequirements and the information needed to execute each step is available when thestep is executed. ln a first step 210, a signal Sioad representing the varying load experienced by the atleast one component 150, 152, 153, 154 is determined.

According to various embodiments of the present invention, the varying load signalSioad may be determined based on measurements, e.g. based on the signalsprovided by the above mentioned one or more sensors 169. The varying load signalSioad may also be determined as an estimated and/or modelled signal.

Further, the varying load signal Sioad may be determined as a predicted signal, whichmay e.g. be based on positioning information. Generally, information related to a roadsection ahead of the vehicle, which may be used for such predictions, may beretrieved in a large number of ways. For example, the information may be determinedon the basis of map data, e.g. from digital maps in combination with positioninginformation, e.g. GPS information. The positioning information may be used todetermine the location of the vehicle in relation to the map data so that relevantinformation may be extracted from the map data. Various present-day cruise controlsystems use map data and positioning information. Such systems may then providethe map data and the positioning information needed for performing theembodiments of the present invention, thereby minimizing the additional complexityinvolved in determining information related to the upcoming road section. By usage ofpositioning information and digital map information, the embodiments of the presentinvention may virtually look ahead along an upcoming road section in order todetermine information related to the road section, such as e.g. inclinations/slopes,that might even not yet be visible from the vehicle, and which may be useful to determine an upcoming load for the one or more components. 17 Also, information related to the upcoming road section may be provided by othervehicles by so-called vehicle to vehicle (V2V) communication, and/or may beprovided by one or more infrastructure entities by so-called vehicle to infrastructure(V2l) communication. Thus, other vehicles travelling the road section may thenreport/provide information, such as e.g. inclinations/slopes, rolling resistance and/orair resistance, to the vehicle 100, either directly (V2V) or via an infrastructure entity(V2l). The vehicle 100 itself may also gather information when travelling a roadsection, which may be used if the vehicle 100 again approaches the same roadsection. The information may be gathered in essentially any suitable way, e.g. byusage of one or more sensors, one or more cameras and/or one or more radarequipment, included in the vehicle 100, in another vehicle and/or in an entity externalfrom the vehicles, such as an infrastructure entity. ln a second step 220, extreme values Sexii_1, Sexii_2, Sexii_ix for the varying loadsignal Sieeii are determined. According to an embodiment, the extreme values Sexii_1,Sexii_2, Sexii_ix are sampled values of the varying load signal Sieeii. ln a third step 230, the extreme values Sexii_1, Sexii_2, Sexii_ix determined in thesecond step 220 are stored in a buffer memory 140. The buffer memory 140 oftenhas a limited storage capacity. For example, in a vehicle implementation, the buffer memory 140 is often limited in size. ln a fourth step 240, at least one closed cycle is determined to be included in thevarying load signal Sieeii. This determination 240 of each one of the closed cycleincluded in the varying load signal Sieeii is here based on three consecutive extremevalues Sexii_ix-2, Sexii_ix-1, Sexii_ix stored in buffer memory 140. According to anembodiment of the present invention, the three consecutive extreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix are the last three values in the buffer memory 140. ln a fifth step 250, at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_iirelated to the at least one determined closed cycle, respectively, is determined. Thisat least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii may, according toherein described embodiment, be of a number of different forms/types. Essentially,any one or more values being useful for representing/defining/indicating/describing a lO 18 closed cycle of the varying load signal Sieeii may be used as cycle representing value Scycle_1, Scycle_2, ..., Scycle_n. ln a sixth step 260, the at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii determined in the fifth step 250 is stored in at least one closed cycle datamemory 180. ln a seventh step 270, at least one of the three consecutive extreme values Sexii_ix-2,Sexii_ix-1, Sexii_ix of each determined closed cycle are deleted from the buffer memory140. ln an eighth step 280, at least one action is performed based on at least one cyclerepresenting value Seyeie_1, Seyeie_2, Seyeie_ii stored in the at least one closed cycledata memory 180. A number of such possible actions are described below.

Thus, according to the present invention, closed cycles in the varying loadexperienced by the one or more components are efficiently identified, and informationrepresenting these closed cycles are stored for further usage. The necessarymeasures/actions needed to be performed in order to mitigate the component fatiguemay reliably be determined based on these closed cycle representing values.Therefore, one or more of the extreme values Sexii_1, Sexii_2, Sexii_ix in the buffermemory 140, that are related to the stored closed cycle representing values, may besafely deleted.

Thus, the reliable identification of the closed cycles, and the storage of the cyclerepresenting values in the at least one closed cycle memory makes it possible todelete data related to one or more extreme values previously being stored in thebuffer memory. This facilitates that a buffer memory of restricted size may be utilizedfor handling the varying loads according to the embodiments of the present invention.

According to an embodiment of the present invention, the number of values I storedin the at least one buffer memory 140 should be at least 3 in order for the fourth 240,the fifth 250, the sixth 260, the seventh 270 and the eighth 280 steps of the methodto be executed. Thus, it may be tested if the number of values l stored in the buffermemory 140 is less than or equal to two; ls2; or not, before the fourth to eighth 240-280 method steps are performed, as is explained more in detail below. lO 19 According to an embodiment of the present invention, schematically illustrated infigure 3a, the above described determination 240 of that at least one closed cycle isincluded in the varying load signal Sioad includes a first step 241 of determining a firstdifference ASeXiU between a first value SeXiLk-z and a second value SeXir_k-1 of thethree consecutive extreme values stored on the buffer memory 140.

The determination 240 of at least one closed cycle also includes a second step 242of determining of a second difference ASexiLz between a second value SeXir_k-1 and athird value Sexig of the three consecutive extreme values stored in the buffermemory 140.

The determination 240 of at least one closed cycle further includes a third step 243 ofdetermining that the three consecutive extreme values SeXiLk-z, SeXir_k-1, Sem; define aclosed cycle if an absolute value of the second difference ASexiLz is greater than orequal to an absolute value of the first difference ASeXiU ; |ASeXir_2| 2 |ASeXir_1|. Thus, ifan absolute value of the second difference ASexiLz is greater than or equal to anabsolute value of the first difference ASeXiU, the cycle is closed, and it may beconcluded that a potentially harmful closed cycle has beendetermined/identified/found_ The at least one cycle representing value ScyueJ, Scyueg, Scyuej being stored inthe at least one closed cycle data memory 180 may be of essentially any form/formatwhich may be useful for representing the determined/identified closed cycle. Thus,essentially any value, measure, indicator and/or data being possible to interpret in away describing the closed cycle may be used as cycle representing value Scyueg,Scyueg, Scyc|e_n. Below are some examples of such cycle representing values Scycle_1, Scycle_2, ..., Scycle_n glVen.

According to an embodiment of the present invention, schematically illustrated infigure 3b, the above described determination 250 of the at least one cyclerepresenting value ScyueJ, Scyueg, Scyue_n may include determining 251 anaverage value Smean for a determined closed cycle based on the first value SeXiLk-zand the second value Sexir_k-1 of the three consecutive extreme values; Smean = (SeXiLk-z + SeXir_k-1)/2; and a range value Srange for the determined closed cycle being lO equal to an absolute value of the determined first difference ASeXiU ; Srange = |ASeXir_1|.Then, these average Smean and range Srange values are stored 260 in the at least oneclosed cycle data memory 180.

According to an embodiment of the present invention, schematically illustrated infigure 3b, the above described determination 250 of the at least one cyclerepresenting value ScycieJ, Scycieg, Scycie_n may include determining 252 anaverage value Smean for a determined closed cycle based on the first value SeXiLk-zand the second value SexiLm of the three consecutive extreme values; Smean =(SeXiLk-z + SeXir_k-1)/2; and a maximum value Smax for the determined closed cyclebeing equal a greatest value of the first value Sexiga and the second value SeXir_i<-1;Smax = max(SeXir_k-2, SeXiLm). Then, these average Smean and maximum Smax values are stored 260 in the at least one closed cycle data memory 180.

According to an embodiment of the present invention, schematically illustrated infigure 3b, the above described determination 250 of the at least one cyclerepresenting value ScycieJ, Scycieg, Scycie_n may include determining 253 anaverage value Smean for a determined closed cycle based on the first value SeXiLk-zand the second value SexiLm of the three consecutive extreme values; Smean =(SeXiLk-z + SeXir_k-1)/2; and a minimum value Smin for the determined closed cycle beingequal to a smallest value of the first value Sexiga and the second value SeXiLk-i; Smin= min(SeXif_i<-2, SeXiLm). Then, these average Smean and minimum Smin values are stored 260 in the at least one closed cycle data memory 180.

According to an embodiment of the present invention, schematically illustrated infigure 3b, the above described determination 250 of the at least one cyclerepresenting value ScycieJ, Scycieg, Scycie_n may include determining 254 amaximum value Smax for a determined closed cycle being equal to a greatest value ofthe first value SeXiLk-z and the second value SeXir_k-1 of the three consecutive extremevalues; Smax = max(SeXir_i<-2, Sexir_k-i); and a minimum value Smin for the determinedclosed cycle being equal to a smallest value of the first value SeXiLk-z and the secondvalue SeXir_k-1; Smin = min(SeXir_k-2, SeXiLm). Then, these maximum Smax and minimum Smin values are stored 260 in the at least one closed cycle data memory 180. lO 21 As a skilled person understands, it is also, within the scope of the present invention,possible to represent the close cycle with other values than the herein mentioned values.

According to an embodiment of the present invention, schematically illustrated infigure 3c, the deletion 270 of at least one of the three consecutive stored extremevalues Sexii_ix-2, Sexii_ix-1, Sexig includes deleting 271 a first value Sexigz and a secondvalue Sexig-i of the three consecutive extreme values if more extreme values thanthe three consecutive stored extreme values Sexii_ix-2, Sexii_ix-1, Sexig are stored in thebuffer memory 140.

According to an embodiment of the present invention, schematically illustrated infigure 3c, the deletion 270 of at least one of the three consecutive stored extremevalues Sexii_ix-2, Sexii_ix-1, Sexig includes deleting 272 a first value Sexigz and a secondvalue Sexig-i of the three consecutive extreme values if an absolute value |ASbiiffei| ofa difference between the first Sexii_1 and the third Sexii_s extreme values in the buffermemory 140 is smaller than a buffer threshold value ASbiiifeLiii; |ASiiiiirei| < ASbiiifeLiii.The buffer threshold value ASbiiifeLiii may be related to the accuracy at which the loadsignal Sieeii is measured, predicted and/or estimated, and may e.g. have a value inthe same order of magnitude as the accuracy of a sensor used for determining theload signal Sieeii, for example 1 % of the total range of a measured signal.

According to an embodiment of the present invention, schematically illustrated infigure 3c, the deletion 270 of at least one of the three consecutive stored extremevalues Sexii_ix-2, Sexii_ix-1, Sexig includes deleting 273 the first value Sexii_ix-2 of the threeconsecutive extreme values if three or less extreme values are stored in the buffermemory 140 and if an absolute value |ASbiiifei| of a difference between the first Sexii_1and the third Sexig extreme values in the buffer memory 140 is equal to or greaterthan a buffer threshold value ASbiiifeLiii; |ASbiiirei| 2 ASbiiffeLiii. As mentioned above, thebuffer threshold value ASbiiifeLiii may be related to the accuracy at which the loadsignal Sieeii is measured, predicted and/or estimated, and may have a value in thesame order of magnitude as the accuracy of e.g. a load sensor. lO 22 Figure 4 shows a non-Iimiting example of a varying load signal Sieeii, which will beused for explaining the principles of the present invention. The non-Iimiting examplewill describe how some of the embodiments of the present invention work. But, as isclear for a skilled person, corresponding principles will also apply for otherembodiments within the scope of the present invention.

As illustrated in figure 4, the varying load signal Sieeii has a varying amplitude, whichmay be related to essentially any varying load, such as e.g. a varying rotationalspeed, a varying pressure and/or a varying temperature, as mentioned above.

Table 1 below shows the sampled extreme values Sexii_1, Sexii_2, Sexii_ix of thevarying load signal Sieeii in the first column. ln the following columns of table 1, thecontents of the buffer memory 140 (B) at various points in time and/or at varioussteps of the method (B1, B2, B14 in the table) are illustrated, as the sampledextreme values Sexii_1, Sexii_2, Sexii_ix of the varying load signal Sieeii are taken careof. ln the second last row of the table, the comparison of the number of values lstored in the buffer memory 140 (B) is commented (“Comp. with l” in the table). ln thelast row, the values being stored in the closed cycle memory 180 (CC in the table) are indicated.

Signal B1 B2 B3 B4 B5 B6 B7 B8 B9 B10 B11 B12 B13 B14 B15 B16 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 5 5 5 1 1 1 8 8 8 8 8 8 8 8 8 8 8 8 8 2 2 2 2 4 4 4 1 1 1 1 1 1 1 1 7 7 7 7 7 7 2 2 2 2 6 6 6 0 0 0 0 0Comp. ls2 ls2 4<5 7>4 ls2 6<8 2<6 3>2 7<8 6<7 5<6 4<5 6>4 7>6 828 ls2 With à à à à à I save save Save Save SaveStoredvalues 5-1 2-4 2-6 1-7 0-8 CCTable 1. lnitially, at B1, the varying load signal Sieeii has a zero (0) extreme value, which isstored 230 in the buffer memory 140 (B1). The number of values l stored in the buffermemory is one, which is less than 2; ls2; wherefore no deletions 270 from the buffer memory 140 and storage 260 in the close cycle memory 180 should be performed. lO 23 At B2, the varying load signal Sieeii has an extreme value of five (5), which is stored230 in the buffer memory 140 (B2). The number of values stored in the buffermemory is two, which fulfils the condition ls2; wherefore no deletions 270 from thebuffer memory 140 and storage 260 in the close cycle memory 180 should beperformed.

At B3, the varying load signal Sieeii has an extreme value of one (1), which is stored230 in the buffer memory 140 (B3). The number of values l stored in the buffermemory is three, which is more than 2; l>2; wherefore a first difference ASexii_1between the first value Sexii_ix-2 and a second value Sexii_ix-1 of the three consecutiveextreme values (the three values in the buffer memory at B3 in the table) and asecond difference ASexii_2 between the second value Sexii_ix-1 and the third valueSexii_ix of the three consecutive extreme values are determined and compared. At B3,ASexii_1=5 and ASexii_2=4, which means that |ASexii_1| > |ASexii_2| and no closed cycleis identified.

At B4, the varying load signal Sieeii has an extreme value of eight (8), which is stored230 in the buffer memory 140 (B4). The number of values l stored in the buffermemory four, which is more than 2; l>2; wherefore a first difference ASexii_1 betweenthe first value Sexii_ix-2 and a second value Sexii_ix-1 of the three consecutive extremevalues (i.e. the last three values in the buffer memory at B4 in the table) and asecond difference ASexii_2 between the second value Sexii_ix-1 and the third valueSexii_ix of the three consecutive extreme values are determined and compared. At B4,ASexii_1=4 and ASexii_2=7, which means that |ASexii_2| z |ASexii_1| and a closed cycle isidentified. Then, at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_iirelated to the determined/identified closed cycle should be determined and stored inthe closed cycle memory 180. According to the non-limiting example illustrated intable 1, at least one cycle representing value is determined based on the first valueSexii_ix-2 (5) and the second value Sexii_ix-1 (1) of the three consecutive extreme values(the three last values in the buffer memory at B4 in the table) and stored in the closedcycle memory 180. The first Sexii_ix-2 (5) and second Sexii_ix-1 (1) values of the threeconsecutive extreme values are then deleted from the buffer memory 140. lO 24 At B5, the number of values stored in the buffer memory is two, which fulfil therequirement; ls2; wherefore no deletions 270 from the buffer memory 140 and nostorage 260 in the close cycle memory 180 should be performed.

At B6, the varying load signal Sieeii has an extreme value of two (2), which is stored230 in the buffer memory 140 (B6). The number of values l stored in the buffermemory is three, which is more than 2; l>2; wherefore a first difference ASexii_1between the first value Sexii_ix-2 and a second value Sexig-i of the three consecutiveextreme values (the three values in the buffer memory at B6 in the table) and asecond difference ASexii_2 between the second value Sexig-i and the third valueSexig of the three consecutive extreme values are determined and compared. At B6,ASexii_1=8 and ASexii_2=6, which means that |ASexii_1| > |ASexii_2| and no closed cycleis identified.

At B7, the varying load signal Sieeii has an extreme value of four (4), which is stored230 in the buffer memory 140 (B7). The number of values l stored in the buffermemory is four, which is more than 2; l>2; wherefore a first difference ASexii_1between the first value Sexii_ix-2 and a second value Sexig-i of the three consecutiveextreme values (the three last values in the buffer memory at B7 in the table) and asecond difference ASexii_2 between the second value Sexig-i and the third valueSexig of the three consecutive extreme values are determined and compared. At B7,ASexii_1=6 and ASexii_2=2, which means that |ASexii_1| > |ASexii_2| and no closed cycleis identified.

At B8, the varying load signal Sieeii has an extreme value of one (1), which is stored230 in the buffer memory 140 (B8). The number of values l stored in the buffermemory is five, which is more than 2; l>2; wherefore a first difference ASexii_1between the first value Sexii_ix-2 and a second value Sexig-i of the three consecutiveextreme values (the three last values in the buffer memory at B8 in the table) and asecond difference ASexii_2 between the second value Sexig-i and the third valueSexig of the three consecutive extreme values are determined and compared. At B8,ASexii_1=2 and ASexii_2=3, which means that |ASexii_2| z |ASexii_1| and a closed cycle isidentified. At least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii related to the determined/identified closed cycle should therefore be determined and stored in lO the closed cycle memory 180. According to the non-Iimiting example illustrated intable 1, at least one cycle representing value is determined based on the first valueSexig-z (2) and the second value Sexig-1 (4) of the three consecutive extreme values(the three last values in the buffer memory at B8 in the table) is determined andstored in the closed cycle memory 180. The first Sexig-2 (2) and second Sexig-i (4)values of the three consecutive extreme values are then deleted from the buffermemory 140.

At B9, the number of values l stored in the buffer memory is three, which is more than2; l>2; wherefore a first difference ASexii_i between the first value Sexig-z and asecond value Sexig-1 of the three consecutive extreme values (the three last valuesin the buffer memory at B9 in the table) and a second difference ASexii_2 between thesecond value Sexig-i and the third value Sexig of the three consecutive extremevalues are determined and compared. At B9, ASexii_i=8 and ASexii_2=7, which means that |ASexii_1| > |ASexii_2| and no closed cycle is identified.

At B10, the varying load signal Sieeii has an extreme value of seven (7), which isstored 230 in the buffer memory 140 (B10). the number of values l stored in thebuffer memory is four, which is more than 2; l>2. A first difference ASexii_1 betweenthe first value Sexig-2 and a second value Sexig-i of the three consecutive extremevalues (the three last values in the buffer memory at B10 in the table) and a seconddifference ASexii_2 between the second value Sexigi and the third value Sexig of thethree consecutive extreme values are determined and compared. At B10, ASexii_i=7and ASexii_2=6, which means that |ASexii_1| > |ASexii_2| and no closed cycle isidentified.

At B11, the varying load signal Sieeii has an extreme value of two (2), which is stored230 in the buffer memory 140 (B11). The number of values l stored in the buffermemory is five, which is more than 2; l>2. A first difference ASexii_1 between the firstvalue Sexig-z and a second value Sexig-i of the three consecutive extreme values(the three last values in the buffer memory at B11 in the table) and a seconddifference ASexii_2 between the second value Sexigi and the third value Sexig of thethree consecutive extreme values are determined and compared. At B11, ASexii_1=6 lO 26 and ASexii_2=5, which means that |ASexii_1| > |ASexii_2|, and that no closed cycle isidentified.

At B12, the varying load signal Sieeii has an extreme value of six (6), which is stored230 in the buffer memory 140 (B12). The number of values l stored in the buffermemory is six, which is more than 2; l>2. A first difference ASexii_1 between the firstvalue Sexii_ix-2 and a second value Sexii_ix-1 of the three consecutive extreme values(the three last values in the buffer memory at B12 in the table) and a seconddifference ASexii_2 between the second value Sexii_i<-1 and the third value Sexii_ix of thethree consecutive extreme values are determined and compared. At B12, ASexii_1=5and ASexii_2=4, which means that |ASexii_1| > |ASexii_2|, and that no closed cycle isidentified.

At B13, the varying load signal Sieeii has an extreme value of zero (O), which is stored230 in the buffer memory 140 (B13). The number of values l stored in the buffermemory is seven, which is more than 2; l>2; wherefore a first difference ASexii_1between the first value Sexii_ix-2 and a second value Sexii_i<-1 of the three consecutiveextreme values (the three last values in the buffer memory at B13 in the table) and asecond difference ASexii_2 between the second value Sexii_i<-1 and the third valueSexii_ix of the three consecutive extreme values are determined and compared. AtB13, ASexii_1=4 and ASexii_2=6, which means that |ASexii_2| > |ASexii_1| and a closedcycle is identified. At least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_iirelated to the determined/identified closed cycle should therefore be determined andstored in the closed cycle memory 180. According to the non-limiting exampleillustrated in table 1, at least one cycle representing value is determined based on thefirst value Sexii_ix-2 (2) and the second value Sexii_ix-1 (6) of the three consecutiveextreme values (the three last values in the buffer memory at B13 in the table) isdetermined and stored in the closed cycle memory 180. The first Sexii_ix-2 (2) andsecond Sexii_ix-1 (6) values of the three consecutive extreme values are then deletedfrom the buffer memory 140.

At B14, the number of values l stored in the buffer memory is five, which is more than2; l>2; wherefore a first difference ASexii_1 between the first value Sexii_ix_2 and a second value Sexii_ix-1 of the three consecutive extreme values (the three last values lO 27 in the buffer memory at B14 in the table) and a second difference ASexiLz betweenthe second value SeXir_k-1 and the third value SeXiLk of the three consecutive extremevalues are determined and compared. At B14, ASeXif_1=6 and ASeXir_2=7, whichmeans that |ASeXir_2| > |ASeXir_1| and a closed cycle is identified. At least one cyclerepresenting value Seyeie_1, Seyeie_2, Seyeie_n related to the determined/identifiedclosed cycle should therefore be determined and stored in the closed cycle memory180. According to the non-limiting example illustrated in table 1, at least one cyclerepresenting value is determined based on the first value SexiLiez (1) and the secondvalue SeXir_k-1 (7) of the three consecutive extreme values (the three last values in thebuffer memory at B14 in the table) is determined and stored in the closed cyclememory 180. The first Sexir_k-z (1) and second SeXiLk-i (7) values of the three consecutive extreme values are then deleted from the buffer memory 140.

At B15, the number of values l stored in the buffer memory is three, which is morethan 2; l>2; wherefore a first difference ASeXiU between the first value SeXiLk-z and asecond value SeXif_k-1 of the three consecutive extreme values (the three last valuesin the buffer memory at B15 in the table) and a second difference ASexiLz betweenthe second value SeXir_k-1 and the third value SeXiLk of the three consecutive extremevalues are determined and compared. At B15, ASeXir_1=8 and ASeXir_2=8, whichmeans that |ASeXir_2| = |ASeXir_1| and a closed cycle is identified. At least one cyclerepresenting value Seyeie_1, Seyeie_2, Seyeie_n related to the determined/identifiedclosed cycle should therefore be determined and stored in the closed cycle memory180. According to the non-limiting example illustrated in table 1, at least one cyclerepresenting value is determined based on the first value SexiLiez (0) and the secondvalue SeXir_k-1 (8) of the three consecutive extreme values (the three last values in thebuffer memory at B15 in the table) is determined and stored in the closed cyclememory 180. The first Sexir_k-z (0) and second SeXir_i<-1 (8) values of the three consecutive extreme values are then deleted from the buffer memory 140.

At B16, the number of values l stored in the buffer memory is one, which is less than2; l<2; wherefore no deletions 270 from the buffer memory 140 and storage 260 in the close cycle memory 180 should be performed. lO 28 Thus, as explained in detail above for steps B1 to B16, the number of values storedin the buffer memory 140 is controlled based on the closed cycles being included inthe varying load signal Sioad. Such that the buffer memory 140, being of limited size,can efficiently handle the sampled values of the varying load signal Sioad. Valuesrepresenting the found/identified/determined closed cycles are then stored in the closed cycle memory 180 for further processing and/or usage.

The herein described varying load may include essentially any load which hasvarying characteristics over time, i.e. being non-static, regarding its load. Suchalternating loads may include any physical load, such as e.g. a mechanical loadand/or a thermic load. Such varying load may originate from a large number ofcomponents and/or situations. For example, a varying load may originate from avarying rotational speed u) of at least one part of a component, e.g. a turbocompressor 153, wherein the varying load signal Sioad includes rotational speed related values.

The varying load may also originate from a varying temperature T of at least one partof the component, such as an exhaust treatment component 150, an exhaustmanifold 152 and/or an intercooler/charger air cooler 154, wherein the varying load signal Sioad at least includes temperature related values.

The varying load may also originate from a varying torque Tq of an engine 101, amachine 101 and/or another component providing the torque Tq, wherein the varying load signal Sioad at least includes torque related values.

The varying load may also originate from a varying pressure P on at least one part ofthe component 150, 152, 153, 154, wherein the varying load signal Sioad at least includes pressure related values The varying load may also originate from a varying force F on at least one part of thecomponent 150, 152, 153, 154, wherein the varying load signal Sioad at least includes force related values.

The varying load being experienced by, e.g. applied to, the one or more components150, 152, 153, 154 influences the one or more components 150, 152, 153, 154 such lO 29 that the at least one of the one or more components are affected by low cycle fatigue(LCF) as a result of the load changing over time. Thus, at least one of the one ormore materials of which the component is composed may be at least partiallydamaged by material fatigue due to the varying load. As mentioned above, thevariations of the load causing the low cycle fatigue may e.g. be related to a varyingrotational speed of a turbine wheel, an impeller, or some other rotating componentpart experiencing a varying rotational speed over time. The variations of the loadcausing the low cycle fatigue may also be related e.g. to a varying temperature of aturbine house/casing, a compressor house/casing, an exhaust gas manifold, anintercooler, or another component and/or component part experiencing varying temperatures or over time.

As is mentioned above, a varying load is determined/identified and handled by theembodiments of the present invention. Such handling of a varying load may include alarge number of possible actions, decisions and/or considerations being performed,such as essentially any usage of the cycle representing values, including e.g. storingthe values and/or using them as a basis for essentially any computations,calculations, analysis and/or decisions. One such decision made based on the cyclerepresenting values may be that at least one action should be performed. Anotherdecision made based on the cycle representing values may be that at least oneaction should be delayed and/or put on hold. Yet another decision made based onthe cycle representing values may be that no action should be performed at the moment.

However, if it is decided that at least one action should be performed 280, suchactions may include, as schematically illustrated in figure 3d, predicting 285 acomponent failure and/or providing an indication 286 to a driver that a componentfailure is to be expected, e.g. by usage of the input/output device 130.

The at least one action 280 may also include providing an indication 287 to anoffboard entity 190 that a component failure is to be expected. The offboard entity190 may be a server, a gateway, a computer, a control unit, or any other devicebeing arranged for control and/or computations, and is located external from thevehicle 100 in which the component 150, 152, 153, 154 is included. The offboard lO entity 190 may e.g. be included in a fleet management and/or supervisionarrangement/system. The onboard control unit 160 and the offboard entity 190 maycommunicate with each other according to any known wireless communication technique and/or standard.

The at least one action 280 may also include providing 288 the determined averageSmeang, Smeang, Smeamn and range SrangeJ, Srangeg, Srange_m values to theoffboard entity 190 external from the vehicle 100. Hereby, a large part of thecalculations may be performed offboard, which lowers the computationalrequirements onboard the vehicle 100.

The at least one action 280 may also include adjusting 289 at least partly a control ofthe component 150, 152, 153, 154 such that a rate of damage for the component150, 152, 153, 154 is changed. Hereby, the rate of damage for a component may belowered in order to protect the component. Also, the rate of damage for thecomponent may also be increased for one component for some cases in order toprotect one or more other components. For example, the rate of the damage for acomponent may be controlled such that failure of the component may be matched with scheduled maintenance.

According to an embodiment of the present invention, schematically illustrated infigure 3d, the at least one action being performed includes incrementing 281 elementvalues of a rain flow matrix Mrainfiow corresponding to the determined 250 at least onecycle representing value Scycieg, Scycieg, Scycie_n. The rain flow matrix Mrainfiow maye.g. include defined matrix intervals, for example corresponding to predefinedrange/amplitude values along one axis, and corresponding to mean values along theother axis. The rain flow matrix Mrainfiow may thus e.g. include values indicating howmany range/amplitude and mean values have been identified within each rain flow matrix interval, respectively.

Based on the contents of this rain flow matrix Mrainfiow, approximate damagecomputations may be performed. For example, a component failure risk R value maybe determined based on the rain flow matrix Mrainfiow data. lO 31 According to an embodiment of the present invention, schematically illustrated infigure 3d, the at least one action being performed 280 includes determining 282 avalue R representing the risk for failure based on a damage model Mdamage and onthe at least one cycle representing value Scyueg, Scyueg, Scyuej. The at least onecycle representing value Scyueg, Scyueg, Scyue_n may then e.g. be stored in the atleast one closed cycle data memory 180 and/or may be stored in the form of a rainflow matrix Mrainfiow. Thus, according to a non-limiting embodiment, the damagemodel Mdamage is applied on the data of the rain flow matrix Mrainfiow in order to determine the risk for failure representing value R.

Then, risk value R is compared 283 with a risk threshold value Rm. The risk thresholdvalue Rih may depend on for example the severity of a failure, where the thresholdvalue for a component in a safety critical system is lower than the threshold value ofa non-safety critical system. lf the risk value is expressed as a probability of failure,the risk threshold may for example be 1 %. As a non-limiting example, the riskthreshold value Rih may be related to a component failure, which means that if therisk value R exceeds the risk threshold value Rih, this is an indication of a probablecomponent failure, i.e. that the component will break and/or start malfunctioning islikely to occur. The risk threshold value Rih may for example be a level/amplitudevalue, whereby a level/amplitude value of the risk value R is compared with the riskthreshold value Rih to see if it exceeds the risk threshold value Rm or not. The riskthreshold value Rih may for example also be a derivative value, whereby a derivativevalue of the risk value R is compared with the risk threshold value Rih to see if thederivative, i.e. the change over time, of the risk value R exceeds the risk threshold value Rih or not.

At least one action is then performed 284 based on the comparison 283 of the riskvalue R with the risk threshold value Rih. Some of the possible actions 280 described in this document may here be executed.

According to an embodiment of the present invention, schematically illustrated infigure 3d, the determination 282 of the risk for failure representing value R isperformed by first determining 282a at least one partial damage value Dpariiai, and then adding/incrementing 282b the at least one partial damage value Dpariiai to a lO 32 cumulative damage value Deiimiiieiive. This reduces the computational load and/or complexity.

Figure 6 is a flow chart diagram for a number of embodiments of the presentinvention. The method illustrated in figure 6 generally relates to the storage, deletionsand handling of the sampled extreme values Sexii_1, Sexii_2, Sexii_i< of the varyingload signal Sieeii. ln the following, reference is sometimes made to the abovedescribed method steps illustrated in figures 2 and 3a-d corresponding to the steps offigure 6. ln step 601, a sampling signal is provided, having a suitable frequency for catching/sampling the varying load signal, e.g. a frequency of 20 Hz. ln step 602, the varying load signal Sieeii is sampled at the provided sampling signal frequency. ln step 603, it is determined 220 if the sample corresponds to an extreme valueSexii_1, Sexii_2, Sexii_ix for the varying load signal Sieeii. lf it is an extreme value, themethod proceeds to step 604, otherwise it starts over again, i.e. returns to thesampling steps 601 and 602. ln step 604, the sample is added to, i.e. stored in, 230 the at least one buffer memory140. The sample is here stored as the last value in the at least one buffer memory140, and the number of values l in the at least one buffer memory 140 is increasedwith one (1). The method then proceeds to step 605. ln step 605, it is checked if the number of values in the at least one buffer memory140 exceeds two (2); i.e. ifl > 2. lfl > 2, then the method proceeds to step 606,othen/vise it returns to the sampling steps 601 and 602. ln step 606, a first difference ASexii_1 between the first value Sexii_ix_2 and the secondvalue Sexii_ix-i of the three last consecutive extreme values in the buffer memory 140is determined 241. Also, a second difference ASexii_2 between a second value Sexii_i<-1and a third value Sexii_ix of the three last consecutive extreme values in the buffermemory 140 is determined 242 is determined 242. The method then proceeds to step607. lO 33 ln step 607, it is determining 243 if the three consecutive extreme values Sexii_i<-2,Sexii_ix-i, Sexii_ix define a closed cycle by a determination of if an absolute value of thesecond difference ASexii_2 is greater than or equal to an absolute value of the firstdifference ASexii_i; |ASexii_2| z |ASexii_i|. lf |ASexii_2| z |ASexii_1| is true, then a closedcycle has been identified and the method proceeds to step 608. Othervvise, themethod proceeds to step 612. ln step 608, at least one cycle representing value Seyeie_i, Seyeie_2, Seyeie_ii relatedto the identified closed cycle is determined 250. The , at least one cycle representingvalue Seyeie_i, Seyeie_2, Seyeie_ii may have any form described in this document. Theat least one cycle representing value Seyeie_i, Seyeie_2, Seyeie_ii is then stored 260 inthe least one closed cycle data memory 180 for further use, e.g. as a basis for one ormore actions and/or for updating values of a rain flow matrix Mieiiiiiew, as described above. The method then proceeds to step 609. ln step 609, it is checked 271, 272 if more extreme values than the three consecutivestored extreme values Sexii_ix-2,Sexii_ix-1, Sexii_ix are stored in the buffer memory 140,i.e. ifl >3, or if an absolute value |ASiiiiffei| of a difference between the first Sexii_1 anda third Sexii_s extreme values is smaller than a buffer threshold value ASiiiiireLiii;|ASbiiirei| < ASbiiffeLiii. lf one or more of these conditions are true, the method proceedsto step 610, otherwise it proceeds to step 611. ln step 610, the first value Sexii_ix-2 and the second value Sexii_ix-i of the three lastconsecutive extreme values stored in the buffer memory 140 are deleted 271, 272.Also, the number of values l in the at least buffer memory 140 is reduced with two (2);l(-l-2. Then the method returns to the sampling steps 601, 602 again. ln step 611, the first value Sexii_ix-2 of the three last consecutive extreme valuesstored in the buffer memory 140 is deleted 273. Also, the number of values l in the atleast buffer memory 140 is reduced with one (1 ); l(-I-1. Then the method returns to the sampling steps 601, 602 again. ln step 612, it is determined if the number of values l in the at least one buffer memory 140 exceeds a maximal allowed number of values liiiex; i.e. ifl > lmex. lfl > liiiex lO 34 then the method proceeds to step 613, otherwise the method returns to the samplingsteps 601, 602. ln step 613, it is determined if the number of values l of the at least one buffermemory 140 is an even or an odd number. lfl is even, the method proceeds to step614. lfl is odd, the method proceeds to step 615. ln step 614, at least one representative value Siepi_i, Siepi_2, Siepg related to thesecond Sexig-i and third Sexig of the three last consecutive extreme values stored inthe buffer memory 140 is determined, including e.g. a mean/average value, a rangevalue, a maximum value, a minimum value, or essentially any other value which mayrepresent the second Sexig-i and third Sexig of the three last consecutive extremevalues. The at least one cycle representative value Siepi_i, Siepi_2, Siepg is thenstored 260 in the least one closed cycle data memory 180 for further use, e.g. as abasis for one or more actions and/or for updating values of a rain flow matrix Mieiiifiew.Also, the second Sexig-i and third Sexig of the three last consecutive extreme valuesstored in the buffer memory 140 are deleted, and the number of values l in the atleast buffer memory 140 is reduced with two (2); l(-I-2. The method then returns tothe sampling steps 601, 602. ln step 615, at least one representative value Siepi_i, Siepi_2, Siepg related to thefirst Sexig-z and second Sexig-i of the three last consecutive extreme values stored inthe buffer memory 140 is determined, including e.g. a mean/average value, a rangevalue, a maximum value, a minimum value, or essentially any other value which mayrepresent the first Sexig-2 and second Sexig-i of the three last consecutive extremevalues. The at least one cycle representative value Siepi_i, Siepi_2, Siepg is thenstored 260 in the least one closed cycle data memory 180 for further use, e.g. as abasis for one or more actions and/or for updating values of a rain flow matrix Mieiiifiew.Also, the first Sexig-z and second Sexig-i of the three last consecutive extreme valuesstored in the buffer memory 140 are deleted, and the number of values l in the atleast buffer memory 140 is reduced with two (2); l(-I-2. The method then returns tothe sampling steps 601, 602. lO According to an aspect of the present invention, a control unit 160 arranged fordetermining and handling a varying load being applied to at least one part ofacomponent 150, 152, 153, 154 is presented.

The control unit 160 is configured for, e.g. includes means for: - determining 210, e.g. by use of a first determination unit 161, a signal Sieeiirepresenting the varying load; - determining 220, e.g. by use of a second determination unit 162, extreme valuesSexii_1, Sexii_2, Sexii_ix for the varying load signal Sieeii; - storing 230, e.g. by use of a third storage unit 163, the extreme values Sexii_1, Sexii_2, Sexii_|x in a buffer memory 140; - determining 240, e.g. by use of a fourth determination unit 164, that at least oneclosed cycle is included in the varying load signal Sieeii, the determining 240 of eachincluded closed cycle being based on three consecutive extreme values Sexii_ix-2,Sexii_ix-1, Sexii_ix stored in the buffer memory; - determining 250, e.g. by use of a fifth determination unit 165, at least one cyclerepresenting value Seyeie_1, Seyeie_2, Seyeie_ii related to at least one determinedclosed cycle, respectively; - storing 260, e.g. by use of a sixth storage unit 166, the determined at least onecycle representing value Seyeie_1, Seyeie_2, Seyeie_ii in at least one closed cycle datamemory 180; - deleting 270, e.g. by use of a seventh deletion unit 167, at least one of the threeconsecutive extreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix of each determined closed cyclefrom the buffer memory 140; and - performing 280, e.g. by use of an eighth performance unit 168, at least one actionbased on the at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii storedin the at least one closed cycle data memory 180.

The control unit 160, e.g. a device or a control device, according to the presentinvention may be arranged for performing all of the above, in the claims, and in theherein described embodiments method steps. The control unit 160 is hereby providedwith the above described advantages for each respective embodiment. 36 According to an aspect of the present invention, a vehicle 100 including/comprisingthe control unit 160 arranged for determining and handling a varying load beingapplied to at least one part of a component 150, 152, 153, 154 is presented.

According to various embodiments of the present invention, the vehicle also includesat least one communication device 170, being essentially any device arranged fortransferring information between the vehicle 100, and the at least one entity 190external to the vehicle 100, e.g. via vehicle-to-vehicle (V2V) communication, vehicle-to-infrastructure (V2l) communication, and/or a vehicle-to-everything (V2X)communication, such that communication between the vehicle 100 and the at least one external entity 190 is achieved/provided.

One or more of the herein described steps of the method may then beexecuted/performed in the at least one offboard entity 190 offboard the vehicle. Thus,the control unit 160 may then be at least partly implemented in an offboard entity 190external from the vehicle. Of course, the information needed for the offboard entity190 to perform its method steps is then transferred/transmitted from the vehicle 100to the offboard entity 190, via the at least one communication device.

Thus, the herein method steps may be completely performed/executed onboard thevehicle 100 in an onboard control unit 160, may be completely performed/executedoffboard the vehicle 100 in a control unit 160 implemented in at least one offboardentity 190, or may be partly performed/executed onboard the vehicle 100 and partlyoffboard the vehicle 100 in a control unit 160 being implemented partly onboard and partly offboard the vehicle in at least one offboard entity 190.

The person skilled in the art will appreciate that a the herein described embodimentsmay also be implemented in a computer program, which, when it is executed in acomputer, instructs the computer to execute the method. The computer program isusually constituted by a computer program product 503 stored on a non-transitory/non-volatile digital storage medium, in which the computer program isincorporated in the computer-readable medium of the computer program product.The computer-readable medium comprises a suitable memory, such as, for example:ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM lO 37 (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a harddisk unit, etc.

Figure 5 shows in schematic representation a control, signal processing and/orprocessor unit 500/160/170, which may correspond to or may at least partly includeone or more of the above-mentioned control units 161, 162, 163, 164, 165, 166, 167,168, i.e. a first determination unit 161 performing the first method step 210, a seconddetermination unit 162 performing the second method step 220, a third storage unit163 performing the third method step 230, a fourth determination unit 164 performingthe fourth method step 240, a fifth determination unit 165 performing the fifth methodstep 250, a sixth storage unit 166 performing the sixth method step 260, a seventhdeletion unit 167 performing the seventh method step, and an eighth performanceunit 168 performing the eighth method step 280. The control, signal processingand/or processor unit 500/160/170 comprises a computing unit 501, which can beconstituted by essentially any suitable type of processor or microcomputer, forexample a circuit for digital signal processing (Digital Signal Processor, DSP), or acircuit having a predetermined specific function (Application Specific IntegratedCircuit, ASIC). The computing unit 501 is connected to a memory unit 502 arrangedin the control, signal processing and/or processor unit 500/160/170, which memoryunit provides the computing unit 501 with, for example, the stored program codeand/or the stored data which the computing unit 501 requires to be able to performcomputations. The computing unit 501 is also arranged to store partial or final results of computations in the memory unit 502. ln addition, the control, signal processing and/or processor unit 500/160/170 isprovided with devices 511, 512, 513, 514 for receiving and transmitting input andoutput signals. These input and output signals can contain waveforms, impulses, orother attributes which, by the devices 511, 513 for the reception of input signals, canbe detected as information and can be converted into signals which can beprocessed by the computing unit 501. These signals are then made available to thecomputing unit 501. The devices 512, 514 for the transmission of output signals are arranged to convert signals received from the computing unit 501 in order to create lO 38 output signals by, for example, modulating the signals, which can be transmitted to other parts of and/or systems in the vehicle.

Each of the connections to the devices for receiving and transmitting input and outputsignals can be constituted by one or more of a cable; a data bus, such as a CAN bus(Controller Area Network bus), a MOST bus (Media Orientated Systems Transportbus), or some other bus configuration; or by a wireless connection. A person skilledin the art will appreciate that the above-stated computer can be constituted by thecomputing unit 501 and that the above- stated memory can be constituted by thememory unit 502.

Control systems in modern vehicles commonly comprise communication bus systemsconsisting of one or more communication buses for linking a number of electroniccontrol units (ECU's), or controllers, and various components located on the vehicle.Such a control system can comprise a large number of control units and theresponsibility for a specific function can be divided amongst more than one controlunit. Vehicles of the shown type thus often comprise significantly more control unitsthan are shown in figures 1 and 5, which is well known to the person skilled in the artwithin this technical field. ln a shown embodiment, the present invention may be implemented by the one ormore above mentioned control units 161, 122, 163, 164, 165, 166, 167, 168. Theinvention can also, however, be implemented wholly or partially in one or more othercontrol units already present in the vehicle, or in some control unit dedicated to the present invention.

Here and in this document, units are often described as being arranged forperforming steps of the method according to the invention. This also includes that theunits are designed to and/or configured to perform these method steps.

The one or more control units 161, 162, 163, 164, 165, 166, 167, 168 are in figure 1illustrated as separate units. These units 161, 162, 163, 164, 165, 166, 167, 168may, however, be logically separated but physically implemented in the same unit, orcan be both logically and physically arranged together. These units 161, 162, 163,164, 165, 166, 167, 168 may for example correspond to groups of instructions, which 39 can be in the form of programming code, that are input into, and are utilized by aprocessor/computing unit 501 when the units are active and/or are utilized for performing its method step, respectively.

The present invention is not limited to the above described embodiments. lnstead,the present invention relates to, and encompasses all different embodiments being included within the scope of the independent claims.

Claims

lO Claims

1. Method (200) for determining and handling a varying load being appliedto a component (150, 152, 153, 154); the method including: - determining (210) a signal Sieeii representing said varying load; - determining (220) extreme values Sexii_1, Sexii_2, Sexii_ix for said varying loadsignal Sieeii; - storing (230) said extreme values Sexii_1, Sexii_2, Sexii_ix in a buffer memory (140);- determining (240) that at least one closed cycle is included in said varying loadsignal Sieeii, said determining (240) of each included closed cycle being based onthree consecutive extreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix stored in said buffer memory(140); - determining (250) at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_iirelated to said at least one determined closed cycle, respectively; - storing (260) said determined at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii in at least one closed cycle data memory (180); - deleting (270) at least one of said three consecutive extreme values Sexii_ix-2, Sexii_ix-1,Sexii_ix of each determined closed cycle from said buffer memory (140); and - performing (280) at least one action based on at least one cycle representing valueSeyeie_1, Seyeie_2, Seyeie_ii stored in said at least one closed cycle data memory(180), wherein said determining (240) that at least one closed cycle is included in saidvarying load signal Sieeii includes: - determining (241) a first difference ASexii_1 between a first value Sexii_ix_2 and asecond value Sexii_ix-1 of said three consecutive extreme values; - determining (242) a second difference ASexii_2 between a second value Sexii_ix-1 anda third value Sexii_ix of said three consecutive extreme values; and - determining (243) that said three consecutive extreme values Sexii_ix-2, Sexii_i<-1,Sexii_ix defines a closed cycle if an absolute value of said second difference ASexii_2 isgreater than or equal to an absolute value of said first difference ASexii_1; |ASexii_2| 2|ASexir_1|.

2. Method (200) as claimed in claim 1, wherein said determining (250) eachof said at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii includes onein the group of: - determining (251) an average value Siiieeii for a determined closed cycle based onsaid first value Sexig-z and said second value Sexig-1 of said three consecutiveextreme values; Smeeii = (Sexig-z + Sexii_ix-1)/2; and a range value Sieiige for saiddetermined closed cycle being equal to an absolute value of said determined firstdifference ASexii_1; Sieiige = |ASexii_1|; - determining (252) an average value Siiieeii for a determined closed cycle based onsaid first value Sexig-z and said second value Sexig-1 of said three consecutiveextreme values; Siiieeii = (Sexigz + Sexii_ix-1)/2; and a maximum value Smex for saiddetermined closed cycle () being equal a greatest value of said first value Sexig-z andsaid second value Sexii_ix-1; Siiiex = max(Sexig-2, Sexii_ix-i); - determining (253) an average value Siiieeii for a determined closed cycle based onsaid first value Sexig-z and said second value Sexig-1 of said three consecutiveextreme values; Siiieeii = (Sexigz + Sexii_ix-1)/2; and a minimum value Smiii for saiddetermined closed cycle being equal to a smallest value of said first value Sexig-zand said second value Sexii_ix-1; Siiiiii = min(Sexig-2, Sexii_ix-1); - determining (254) a maximum value Siiiex for a determined closed cycle () beingequal to a greatest value of said first value Sexigz and said second value Sexii_ix-1 ofsaid three consecutive extreme values; Smex = max(Sexii_ix-2, Sexii_ix_1); and a minimumvalue Siiiiii for said determined closed cycle being equal to a smallest value of said first value Sexig-z and said second value Sexii_ix-1; Siiiiii = min(Sexig2, Sexii_ix_1).

3. Method (200) as claimed in any one of claims 1-2, wherein said deleting(270) at least one of said three consecutive stored extreme values Sexii_ix-2,Sexii_ix-1,Sexig includes one in the group of: - deleting (271) a first value Sexii_ix-2 and a second value Sexig-i of said threeconsecutive extreme values if more extreme values than said three consecutivestored extreme values Sexii_ix-2, Sexii_ix-1, Sexig are stored in said buffer memory (140);- deleting (272) a first value Sexii_ix-2 and a second value Sexig-i of said threeconsecutive extreme values if an absolute value |ASbiiifei| of a difference between said first Sexii_1 and a third Sexii_s extreme values in said buffer memory (140) is lO smaller than a buffer threshold value ASbuffeUh; |ASbufrer| < ASbuffeLih; and - deleting (273) said first value Sexiga of said three consecutive extreme values ifthree or less extreme values are stored in said buffer memory (140) and an absolutevalue |ASbuffer| of a difference between said first Sexig and a third Sema extremevalues in said buffer memory (140) is equal to or greater than a buffer threshold valueASbufreUh; |ASbuffer| 2 ASbufrerJh.

4. Method (200) as claimed in any one of claims 1-3, wherein saidperforming (280) at least one action includes incrementing (281) element values of arain flow matrix Mrainfiow corresponding to said determined (250) at least one cycle representing ValUe Scycle_1, Scycle_2, ..., Scycle_n.

5. Method (200) as claimed in any one of claims 1-4, wherein saidperforming (280) at least one action includes at least: - determining (282) a value R representing said risk for failure based on a damagemodel Mdamage and on said at least one cycle representing value Scycieg, Scycieg, Scycie_n stored in said at least one closed cycle data memory (180); - comparing (283) said risk value R with a risk threshold value Rih; and - performing (284) at least one action based on said comparison (283).

6. Method (200) as claimed in claim 5, wherein said determining (282) ofsaid risk for failure representing value R includes: - determining (282a) at least one partial damage value Dpariiai; and - adding (282b) said at least one partial damage value Dpafiiai to a cumulative damage V8|Ue Dcumulative.

7. Method (200) as claimed in any one of claims 1-6, wherein said varyingload originates from at least one of: - a varying rotational speed u) of at least one part of said component (150, 152, 153,154), wherein said varying load signal Sioad at least includes rotational speed relatedvalues; - a varying temperature T of at least one part of said component (150, 152, 153, 154),wherein said varying load signal Sioad at least includes temperature related values; - a varying torque Tq of one or more of an engine (101 ), a machine (101) and lO another component providing said torque Tq, wherein said varying load signal Sioad atleast includes torque related values; - a varying pressure P on at least one part of said component (150, 152, 153, 154),wherein said varying load signal Sioad at least includes pressure related values; and - a varying force F on at least one part of said component (150, 152, 153, 154), wherein said varying load signal Sioad at least includes force related values.

8. Method (200) as claimed in any one of claims 1-7, wherein said varyingload includes at least one of: - a mechanical load; - a physical load; and - a thermic load.

9. Method (200) as claimed in any one of claims 1-8, wherein saidcomponent (150, 152, 153, 154) is affected by low cycle fatigue (LCF) due to saidvarying load being applied to said component (150, 152, 153, 154).

10. Method (200) as claimed in any one of claims 1-9, wherein saidperforming (280) at least one action includes at least one in the group of: - predicting (285) a component failure; - indicating (286) to a driver that a component failure is to be expected; - indicating (287) to an entity (190) external from a vehicle (100) in which saidcomponent (150, 152, 153, 154) is included that a component failure is to beexpected; - providing (288) said average Smeafg, Smeang, Smeamn and range SrangeJ, Srangeg, Srange_m values to an entity (190) external from a vehicle (100) in which saidcomponent (150, 152, 153, 154) is included; and - adjusting (289) at least partly a control of said component (150, 152, 153, 154) suchthat a rate of damage for said component (150, 152, 153, 154) is changed.

11. Computer program comprising instructions which, when the program isexecuted by a computer, cause the computer to carry out the method (200) accordingto any one of the claims1-10. lO

12. Computer-readable medium comprising instructions which, whenexecuted by a computer, cause the computer to carry out the method (200) accordingto any one of the claims 1-10.

13. Control unit (160) arranged for determining and handling a varying loadbeing applied to at least one part of a component (150, 152, 153, 154); the control unit (160) being arranged for: - determining (210) a signal Sieeii representing said varying load; - determining (220) extreme values Sexii_1, Sexii_2, Sexii_ix for said varying loadsignal Sieeii; - storing (230) said extreme values Sexii_1, Sexii_2, Sexii_ix in a buffer memory (140);- determining (240) that at least one closed cycle is included in said varying loadsignal Sieeii, said determining (240) of each included closed cycle being based onthree consecutive extreme values Sexii_ix-2, Sexii_ix-1, Sexii_ix stored in said buffer memory(140); - determining (250) at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_iirelated to said at least one determined closed cycle, respectively; - storing (260) said determined at least one cycle representing value Seyeie_1, Seyeie_2, Seyeie_ii in at least one closed cycle data memory (180); - deleting (270) at least one of said three consecutive extreme values Sexii_ix-2, Sexii_ix-1,Sexii_ix of each determined closed cycle from said buffer memory (140); and - performing (280) at least one action based on said at least one cycle representingvalue Seyeie_1, Seyeie_2, Seyeie_ii stored in said at least one closed cycle datamemory (180), wherein said determining (240) that at least one closed cycle is included in saidvarying load signal Sieeii includes: - determining (241) a first difference ASexii_1 between a first value Sexii_ix_2 and asecond value Sexii_ix-1 of said three consecutive extreme values; - determining (242) a second difference ASexii_2 between a second value Sexii_ix-1 anda third value Sexii_ix of said three consecutive extreme values; and - determining (243) that said three consecutive extreme values Sexii_ix-2, Sexii_i<-1, Sexii_ix defines a closed cycle if an absolute value of said second difference ASexii_2 is greater than or equal to an absolute value of said first difference ASeXiU ; |ASeXir_2| 2|ASextr_1

14. A vehicle (100) including a control unit (160) according to claim 13.