• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    21 Abstract The invention relates to a method for reducing powertrain oscillations in avehicle (1 ), wherein the powertrain (3) of the vehicle (1) comprises an engine(2); a gearbox (4) with an output shaft (8); at least one drive shaft (10)connected to the output shaft (8) of the gearbox (4); at least one driving wheel(6) connected to the at least one drive shaft (10); and at least one wheel brake(12) connected to the at least one driving wheel (6). The method comprises thesteps to: a) determine if the at least one driving wheel (6) is slipping; and if sob) apply the wheel brake (12), such that a predetermined brake force isprovided. The invention also relates to a powertrain (3), a vehicle (1) comprising such a powertrain (3), a computer program (P) and a computer programme product. (Fig. 3)
    公开号:SE1550624A1
    申请号:SE1550624
    申请日:2015-05-15
    公开日:2016-11-16
    发明作者:Udd Jonas；Szilassy Andreas
    申请人:Scania Cv Ab；
    IPC主号:
    专利说明:

    A method for reducing powertrain oscillations TECHNICAL FIELD The present invention relates to a method for reducing powertrain oscillationsaccording to claim 1. The invention also relates to a powertrain according toclaim 6 and a vehicle comprising such a powertrain according to claim 8. Theinvention further relates to a computer program according to claim 9 and a computer program product comprising program code according to claim 10.
    BACKGROUND A powertrain in a vehicle typically comprises a p|ura|ity of components such asan engine, a transmission, drive shafts, differentials and drive wheels. Eachcomponent has a mass which causes a moment of inertia when it rotates. Thecomponents in the powertrain are not completely rigid which means that thepowertrain will have a certain torsional stiffness. The driving torque provided bythe engine causes wind-up of the weaker components of the powertrain, suchas the drive shafts. The drive shafts are thereby subjected to a torsional loadand thus resemble torsion springs. The friction between the driving wheels andthe ground surface is required in order to achieve a rotational motion of thedriving wheel. When the driving torque corresponds to a driving force whichexceeds the friction force, traction is lost and the driving wheel starts slipping.Under certain operating conditions the friction between the driving wheels andthe ground surface is reduced. This could be the case when driving on softsurfaces as sand, gravel, snow or mud. lf the friction force is reduced while thedrive shaft is in a wind-up state, the driving wheel which will start spinning andthe torsional load on the drive shaft will be transferred to the driving wheel. Thedrive shaft thus unwinds and oscillations in the powertrain are created.Powertrain oscillations cause longitudinal vibrations in the vehicle which maybe perceived as unpleasant and thus reduces the driving comfort. Powertrainoscillations may also seriously damage the various components of the powertrain. lt is therefore desirable to avoid powertrain oscillations during alloperating conditions. Powertrain oscillations induced by slipping driving wheels may be referred to as powertrain judder.
    Doeurrierit tïštši (tâíiüášßíššššß Af describes a system for e fotir-wheei drivevehicie comprieihg e cititoh device erreriged between the 'froht vvheeis ehd edrive uriit. A cehtroi urtit ie adapted to modify the ciuteh tordtie vvhehpowertrain oeoiiietiohe ere identified, end thereby distribute the drive tordtiebetween the driving vvheeis iri order to reduce the povtfertreih oeoiiietiohs. Ûocurneht US20t0ü268429 At describes e ritethod for reducing osciiietiohs ihe vehieie powertrain oecurrihg when drit/irtg oh e eurfeoe hevihg e iovvcoefficiertt of frictioh. The method comprieee the step to trariemit tordue to secondary wheeie.
    SUMMARY OF THE INVENTION Despite known solutions in the field, there is still a need to develop a methodfor reducing powertrain oscillations and thereby improving the driving comfort of a vehicle.
    An object of the present invention is to achieve a method for reducing powertrain oscillations, which improve the manoeuvrability of a vehicle.
    Another object of the present invention is to achieve a powertrain which maybe controlled to reduce oscillations and to improve the manoeuvrability of the vehicle.
    Another object of the present invention is to achieve a new and advantageouscomputer program for controlling a powertrain such that powertrain oscillations are reduced.
    The herein mentioned objects are achieved by a method characterized by the features in the characterizing part of claim 1.
    The herein mentioned objects are achieved by a powertrain characterized bythe features in the characterizing part of claim 6.
    The herein mentioned objects are also achieved by a vehicle characterized bythe features in the characterizing part of claim 8.
    The herein mentioned objects are also achieved by a computer program forcontrolling a powertrain characterized by the features in the characterizing partof claim 9.
    The herein mentioned objects are also achieved by a computer programproduct for controlling a powertrain characterized by the features in thecharacterizing part of claim 10.
    According to an aspect of the present invention a method for reducingpowertrain oscillations in a vehicle is provided. The powertrain of the vehiclecomprises an engine; a gearbox with an output shaft; at least one drive shaftconnected to the output shaft of the gearbox; at least one driving wheelconnected to the at least one drive shaft; and at least one wheel brakeconnected to the at least one driving wheel. The method comprises the stepsto: a) determine if the at least one driving wheel is slipping; and if so b) apply the wheel brake, such that a predetermined brake force is provided. ln the powertrain the engine and the gearbox are connected. The engine andthe gearbox may be connected through a clutch device arranged between theengine and the gearbox. The at least one drive shaft may be connected to adifferential arranged between the output shaft of the gearbox and the driveshafi.
    The powertrain suitably comprises at least two drive shafts and two drivingwheels, wherein one driving wheel is connected to each of the drive shafts.The two driving wheels thus constitute a first driving wheel set. Alternatively,the powertrain comprises at least four drive shafts and four driving wheels,wherein one driving wheel is connected to each of the drive shafts. Thepowertrain thus suitably comprises a first driving wheel set and a seconddriving wheel set.
    Drive shafts are considered to be weak components of a powertrain whichmeans that they will twist when subjected to torsional loads. The drive shaftsare thus more torsionally compliant than other parts of the powertrain, whichother parts will not twist significantly when subjected to torsional loads. twistingof the .When the torque provided by the engine is transmitted through thepowertrain it causes twisting, or wind-up, of the drive shafts before the torquecan be transmitted to the driving wheels. The drive shafts may thereby act astorsion springs. The transmitted torque from the engine corresponds to adriving force acting on the driving wheels. A friction force exists at the point ofcontact between each driving wheel and the ground surface. The friction forceis required in order to achieve a rolling motion of the driving wheel. The frictionforce between a driving wheel and the ground surface may be referred to astraction. Traction may be defined as the maximum amount of force the drivingwheel can apply against the ground surface before it slips. The traction forceand thus the friction force depend on the normal force acting on the drivingwheel and the coefficient of friction between the surface of the driving wheeland the ground surface. The coefficient of friction depends on the twosurfaces. Thus, the coefficient of friction is different for different groundsurfaces. The coefficient of friction between the driving wheels and the groundsurface is for example lower when driving on soft surfaces such as sand,gravel, snow or mud. When the driving force on the driving wheel exceeds thefriction force, traction is lost and the wheel slips and starts spinning. lf the driveshaft is in a wind-up state and the friction force is reduced such that the driving force exceeds the friction force, the torsional load on the drive shaft will betransferred to the driving wheel which is slipping and spinning. The drive shaftwill thereby unwind which causes oscillations in the powertrain. Powertrainoscillations cause longitudinal vibrations in the vehicle which may be perceivedas unpleasant and thus reduces the driving comfort. Powertrain oscillations may also seriously damage the various components of the powertrain.
    By determining the presence of wheel slip and then applying a wheel brakesuch that a predetermined brake force is provided, powertrain oscillations maybe reduced. The provided predetermined brake force will act on the drivingwheel as an additional friction force in an opposite direction to the drivingforce. Thereby, even if the friction force between the driving wheel and theground surface is reduced, the driving force still has to exceed the brake forcebefore the driving wheel starts slipping. By applying the brake force to theslipping driving wheel, the slipping is stopped and the drive shaft is thussubstantially maintained in the wind-up state. By avoiding unwinding of thedrive shaft, oscillations in the powertrain are reduced. This way, a method forreducing powertrain oscillation is achieved, which improves themanoeuvrability of the vehicle.
    A control unit is preferably arranged in communication with the driving wheelsand the wheel brakes. The control unit may also be arranged incommunication with the gearbox and the engine of the powertrain. The controlunit suitably determines if the at least one driving wheel is slipping in step a)and applies the wheel brake such that a predetermined brake force is providedin step b).
    The predetermined brake force is preferably based on the available frictionforce between the driving wheel surface and the ground surface. Thepredetermined brake force is thus suitably based on the normal force acting onthe driving wheel and the coefficient of friction between the two surfaces.Information regarding different coefficients of friction for different ground surfaces may be stored in the control unit. The control unit may also compriseinformation regarding the normal force and other parameters relevant fordetermining the necessary brake force. The predetermined brake force issuitably determined independently of the current torque provided by theengine. Alternatively, the predetermined brake force is a fixed value, independently of the currently available friction force.
    According to an embodiment of the invention the wheel brake is applied in stepb) such that the predetermined brake force is greater than the available frictionforce between the slipping driving wheel and the ground surface. According toan embodiment of the invention the wheel brake is applied in step b) such thatthe predetermined brake force is at least twice as large as the available frictionforce between the slipping driving wheel and the ground surface. Thepredetermined brake force may be at least three times as large as the frictionforce. When driving on a soft ground surface the friction force between thedriving wheel and the ground surface varies. The variation of the friction forcecauses oscillations in the powertrain as the driving force exceeds the frictionforce. Depending on the size of the brake force, the variation in friction forcemay still affect the drive shaft and thus cause oscillations even when thepredetermined brake force is applied on the driving wheel. By applying a brakeforce which is greater than the friction force, the variations in friction force hasless effect on the drive shaft. The brake force is thus the dominant force. Thegreater the difference between the friction force and the brake force, the lesseffect on the drive shaft of the variations in friction force. The predeterminedbrake force is thus preferably significantly greater than the friction force. Thewheel brake is preferably applied in step b) such that a brake force is providedwhich is so much greater than the friction force that any oscillation resultingfrom the varying friction force is negligible.
    According to an embodiment of the invention it is determined if the at least onedriving wheel is slipping in step a) based on the rotational speed of said drivingwheel. The rotational speed is suitably analysed in relation to the transmitted torque from the engine and thus the driving force acting on the driving wheel.The rotational speed is typically determined by speed sensors arranged inconnection with the driving wheels or the drive shaft. The presence of s|ippingmay be determined based on speed variations between different driving wheels.
    Alternatively, it is determined if a driving wheel is s|ipping in step a) byidentifying an oscillation in the powertrain. An oscillation in the powertraincaused by wheel s|ip may be identified by various speed sensors arranged inthe powertrain, for example on the drive shafts, the driving wheels, the engineetc. The speed sensors indicate the rotational speeds of the components in thepowertrain, which rotational speeds are used to detect an oscillation. Anoscillation in the powertrain caused by wheel s|ip may alternatively be identified by the use of a sensor for detecting vibrations in the powertrain.
    According to an embodiment of the invention, the method constitutes anoscillation reducing function which can be manually activated and manuallyinactivated. Step a) may thus be excluded and replaced by the step tomanually activate the function to reduce powertrain oscillations. The operatorof the vehicle may thus manoeuvre an activation means such as a lever,button, switch or menu on a display. When the operator has manuallyactivated the function, the step b) is performed. This may be advantageouswhen the operator concludes that it is very probable that the friction forcebetween the driving wheels and the ground surface will be reduced. Bymanually activating the oscillation reducing function as a preventive measure, the powertrain oscillations may be avoided.
    According to an embodiment of the invention the method further comprises thestep to: c) gradually decrease the brake force to zero as long as the driving wheel isnot s|ipping or is s|ipping with an acceptable s|ip speed while the vehicle is moving.
    A vehicle driving on a soft ground surface such as for example sand mayexperience powertrain judder wherein the driving wheels are slipping andspinning, the drive shafts unwind and powertrain oscillations are created. Thecontrol unit thus determines that at least one driving wheel is slipping in step a)and applies the wheel brake connected to the slipping wheel in step b). Thepowertrain oscillation is thereby reduced and the manoeuvrability of the vehicleis improved. The vehicle is thus propelled with at least one wheel brakeapplied. lt is of course not desirable to unnecessarily drive with continuouslyapplied wheel brakes. ln step c) the brake force is therefore graduallydecreased until the wheel brake is no longer applied, provided that the drivingwheel is not slipping or that it is slipping with an acceptable slip speed whilethe vehicle is moving. The control unit preferably controls the wheel brake suchthat the brake force is decreased. The acceptable slip speed is suitably savedin the control unit. Step c) thus suitably includes to continuously determining ifthe driving wheel connected to the controlled wheel brake is slipping.Preferably, step c) includes decreasing the brake force slightly and thereafterdetermining if the driving wheel is slipping. lf the driving wheel is not slipping orif it is slipping with an acceptable slip speed while the vehicle is moving afterthe decrease, the brake force is once again decreased. lf the driving wheel isslipping more than the acceptable slip speed after the decrease, the brakeforce is increased to the brake force level prior to the decrease. This is suitablyperformed continuously until the wheel brake is no longer applied.
    According to an embodiment of the invention, the wheel brake is automaticallyinactivated when it is determined that the wheel brake is overheated. ln caseof overheating, an alert may be provided to inform the operator that the wheelbrake should be inactivated. The alert may alternatively inform the operatorthat the wheel brake will be automatically inactivated due to overheating.
    According to an embodiment of the invention a powertrain of a vehicle isprovided. The powertrain comprises an engine; a gearbox with an output shaft; at least one drive shaft connected to the output shaft of the gearbox; at leastone driving wheel connected to the at least one drive shaft; and at least onewheel brake connected to the at least one driving wheel. A control unit isconnected to the at least one driving wheel and the at least one wheel brake,wherein the control unit is adapted to determining if the at least one drivingwheel is slipping and, if so, applying the wheel brake such that apredetermined brake force is provided.
    The control unit is preferably adapted to gradually decrease the brake force tozero as long as the driving wheel is not slipping or is slipping with anacceptable slip speed while the vehicle is moving.
    According to an aspect of the invention, a computer program is provided,wherein said computer program comprises programme code for causing anelectronic control unit or a computer connected to the electronic control unit toperform the steps according to the herein mentioned method.
    According to an aspect of the invention a computer programme product isprovided, comprising a programme code stored on a computer-readablemedium for performing the method steps according to the herein mentionedmethod, when said computer programme is run on an electronic control unit or a computer connected to the electronic control unit.
    Further objects, advantages and novel features of the present invention willbecome apparent to one skilled in the art from the following details, and alsoby putting the invention into practice. Whereas the invention is describedbelow, it should be noted that it is not restricted to the specific detailsdescribed. Specialists having access to the teachings herein will recognisefurther applications, modifications and incorporations within other fields, which are within the scope of the invention.
    BRIEF DESCRIPTION OF THE DRAWINGS For fuller understanding of the present invention and further objects andadvantages of it, the detailed description set out below should be read togetherwith the accompanying drawings, in which the same reference notations denote similar items in the various diagrams, and in which: Figure 1 schematically illustrates a vehicle according to an embodiment ofthe invention; Figure 2 schematically illustrates a powertrain according to an embodimentof the invention; Figure 3 illustrates a flow chart for a method according to an embodiment ofthe invention; and Figure 4 schematically illustrates a control unit or computer according to an embodiment of the invention.
    DETAILED DESCRIPTION OF THE DRAWINGS Figure 1 scherriaticaiiy shows a side view of a vehicie 'i according to anembodiment of the invention. The vehicle 1 comprises a powertrain 3 with anengine 2 and a gearbox 4. The gearbox 4 has an output shaft (not shovvn)which is connect to drive shafts (not sitown). The drive shafts are connected tothe driving tivheeis 6 of the vehicie t. Each driving vtfheei ti has an associatedwheei brake (not shown). A controi unit 3G is arranged in communication withthe driving wheeis 6 and the wheei brakes. The controi unit 2G is adapted todetermining if any driving wheel 6 is slipping and, if so, applying the associatedwheel brake such that a predetermined brake force is provided, in order toreduce powertrain oscillations. The vehicle 1 may be a heavy vehicle, e.g. atruck or a bus. The vehicle 1 may alternatively be a passenger car. 11 Figure 2 schematically shows a powertrain 3 of a vehicle 1 according to anembodiment of the invention. The powertrain 3 comprises an engine 2; agearbox 4 with an output shaft 8; at least one drive shaft 10 connected to theoutput shaft 8 of the gearbox 4; at least one driving wheel 6 connected to theat least one drive shaft 10; and at least one wheel brake 12 connected to theat least one driving wheel 6. The engine 2 may be connected to the gearbox 4through a clutch 14. The clutch 14 thus connects on one side to the crankshaft16 of the engine 2 and to an input shaft 18 of the gearbox 4 on the other side.Only two driving wheels 6 and two drive shafts 10 are illustrated in Figure 2,however, any number of driving wheels 6 and drive shafts 10 may be includedin the powertrain 3 within the scope of the invention. The output shaft 8 of thegearbox 4 is connected to the drive shafts 10 through a differential 20. Thedifferential 20 enables distribution of a driving torque provided by the engine 2between the drive shafts 10. The drive shafts 10 are weak components andwill twist when subjected to torsional loads. When the torque provided by theengine 2 is transmitted through the powertrain 3 it causes twisting, or wind-up,of the drive shafts 10 before the torque can be transmitted to the drivingwheels 6. The drive shafts 10 may thereby act as torsion springs between thedifferential 20 and the driving wheels 6. The transmitted torque from the engine2 corresponds to a drive force acting on the driving wheels 6. A friction forceexists at the point of contact between each driving wheel 6 and the groundsurface. The friction force is required in order to achieve a rolling motion of thedriving wheel 6.
    An electronic control unit 30 is arranged in communication with engine 2, theclutch 14, the gearbox 4, the driving wheels 6 and the wheel brakes 12. Thecontrol unit 30 is adapted to determining if any driving wheel 6 is slipping and,if so, applying the associated wheel brake 12 such that a predetermined brakeforce is provided. The control unit 30 may constitute a system with a plurality ofcontrol units arranged in communication with the engine 2, the clutch 14, thegearbox 4, the driving wheels 6 and the wheel brakes 12. A computer 32 maybe connected to the control unit 30. 12 Figure 3 shows a flowchart for a method for reducing powertrain oscillations ina vehicle 1 according to an embodiment of the invention. The powertrain 3 ofthe vehicle 1 is suitably configured as described in Figure 2 and comprises anengine 2; a gearbox 4 with an output shaft 8; at least one drive shaft 10connected to the output shaft 8 of the gearbox 4; at least one driving wheel 6connected to the at least one drive shaft 10; and at least one wheel brake 12connected to the at least one driving wheel 6. The method comprises the stepsto: a) determine if the at least one driving wheel 6 is slipping; and if so b) applythe wheel brake 12, such that a predetermined brake force is provided. This way, powertrain oscillations induced by wheel slipping is reduced.
    When the engine 2 provides a driving torque it causes wind-up of the driveshafts 10 before the torque can be transmitted to the driving wheels 6. Thetransmitted torque from the engine 2 corresponds to a driving force acting onthe driving wheels 6. A friction force exists at the point of contact betweeneach driving wheel 6 and the ground surface. The friction force is required inorder to achieve a rolling motion of the driving wheel 6. The friction forcedepends on the normal force acting on the driving wheel 6 and the coefficientof friction between the surface of the driving wheel 6 and the ground surface.The coefficient of friction depends on the two surfaces. Thus, the coefficient offriction is different for different ground surfaces and different driving wheels 6.The friction force may thus vary when driving on a soft ground surface such assand, gravel or snow. When the driving force on the driving wheel 6 exceedsthe friction force, traction is lost and the wheel 6 slips and starts spinning. lf thedrive shaft 10 is in a wind-up state and the friction force is reduced such thatthe driving force exceeds the friction force, the torsional load on the drive shaft10 will be transferred to the driving wheel 6 which is slipping and spinning. The drive shaft 10 will thereby unwind which causes oscillations in the powertrain 3. ln order to reduce the powertrain oscillations it is determined in step a) if adriving wheel 6 is slipping. lf a driving wheel 6 is slipping the wheel brake 12 13 associated with the slipping driving wheel 6 is applied in step b), such that a predetermined brake force is provided.
    The provided predetermined brake force in step b) will act on the driving wheel6 as an additional friction force in an opposite direction to the driving force.Thereby, even if the friction force between the driving wheel 6 and the groundsurface varies and is reduced, the driving force still has to exceed the brakeforce before the driving wheel starts slipping. By applying the brake force tothe slipping driving wheel 6, the slipping is stopped and the drive shaft 10 isthus substantially maintained in the wind-up state. This way, unwinding of thedrive shaft 10 is avoided and the oscillations in the powertrain 3 are reduced. Amethod for reducing powertrain oscillation is thereby achieved, which improvesthe manoeuvrability of the vehicle 1.
    The control unit 30 suitably determines if the at least one driving wheel 6 isslipping in step a) and applies the wheel brake 12 such that a predeterminedbrake force is provided in step b).
    The predetermined brake force is preferably determined based on theavailable friction force between the driving wheel 6 surface and the groundsurface. The predetermined brake force is thus suitably determined based onthe normal force acting on the driving wheel 6 and the coefficient of frictionbetween the two surfaces. Information regarding different coefficients of frictionfor different ground surfaces may be stored in the control unit 30 and/orcalculated by the control unit 30. The control unit 30 may also compriseinformation regarding the normal force and other relevant parameters fordetermining a sufficient brake force. The predetermined brake force is suitablydetermined independently of the current torque provided from the engine 2.Alternatively, the predetermined brake force is determined as a fixed value, independently of the currently available friction force. 14 According to an embodiment of the invention the wheel brake 12 is applied instep b) such that the predetermined brake force is greater than the availablefriction force between the slipping driving wheel 6 and the ground surface.According to an embodiment of the invention the wheel brake 12 is applied instep b) such that the predetermined brake force is at least twice as large asthe available friction force between the driving wheel 6 and the ground surface.The predetermined brake force may be at least three times as large as thefriction force. Depending on the size of the brake force, variations in the frictionforce may still affect the drive shaft and thus cause small oscillations evenwhen the predetermined brake force is applied on the driving wheel 6. Byapplying a brake force which is greater than the friction force, the variations infriction force has less effect on the drive shaft 10. The brake force is thus thedominant force. The brake force is thus preferably significantly larger than thefriction force. The wheel brake 12 is preferably applied in step b) such that apredetermined brake force is provided, which is sufficiently larger than thefriction force and thereby leads to that any oscillation resulting from the varyingfriction force is negligible. lt is preferably determined if the at least one driving wheel 6 is slipping in stepa) based on the rotational speed of said driving wheel 6. The rotational speedis suitably analysed in relation to the transmitted torque from the engine 2 andthus the driving force acting on the driving wheel 6. The rotational speed is typically determined by speed sensors (not shown) arranged in connection with the driving wheels 6 or the drive shafts 10. The presence of slipping maybe determined based on speed variations between different driving wheels or on speed variations between driving wheels and other wheels. lt may be determined if a driving wheel is slipping in step a) by identifying anoscillation in the powertrain 3. An oscillation in the powertrain 3 induced bywheel slip may be identified by various speed sensors (not shown) arranged inthe powertrain 3. Speed sensors may be arranged in connection to the driveshafts 10, the driving wheels 6, the engine 2 etc. The speed sensors indicate the rotational speeds of the components in the powertrain 3, which rotationalspeeds are used to detect an oscillation. An oscillation in the powertrain 3caused by wheel slip may alternatively be identified by the use of a sensor fordetecting vibrations in the powertrain 3.
    According to an embodiment of the invention, the method constitutes anoscillation reducing function which can be manually activated and manuallyinactivated. Step a) may thus be excluded and replaced by the step tomanually activate the function to reduce powertrain oscillations. The operatorof the vehicle 1 may thus manoeuvre an activation means such as a lever,button, switch or menu on a display. When the operator has manuallyactivated the function, the step b) is performed. This may be advantageouswhen the operator concludes that it is very probable that the friction forcebetween the driving wheels 6 and the ground surface will be reduced. Forexample, if the driver is about to take off while being situated on sand, thedriver may conclude that it is very likely that the driving wheels will startslipping. The driver may then activate the function to reduce powertrainoscillations as a precaution. By manually activating the oscillation reducingfunction as a preventive measure, both wheel slip and powertrain oscillationsmay be avoided.
    According to an embodiment of the invention the method comprises the furtherstep to: c) gradually decrease the brake force to zero as long as the driving wheel 6 isnot slipping or is slipping with an acceptable slip speed while the vehicle is moving.
    When step b) has been performed the vehicle 1 is propelled with at least onewheel brake 12 applied. lt is of course not desirable to unnecessarily drivewith continuously applied wheel brakes 12. ln step c) the brake force istherefore gradually decreased until the wheel brake 12 is no longer applied,provided that the driving wheel 6 is not slipping or is slipping with an 16 acceptable slip speed while the vehicle 1 is moving. The control unit 30preferably controls the wheel brake 12 such that the brake force is decreased.Step c) thus suitably includes to continuously determining if the driving wheel 6connected to the controlled wheel brake 12 is slipping. Preferably, step c)includes decreasing the brake force slightly and thereafter determining if thedriving wheel 6 is slipping. lf the driving wheel 6 is not slipping or if it is slippingwith an acceptable slip speed while the vehicle is moving after the decrease,the brake force is once again decreased. lf the driving wheel 6 is slipping morethan the acceptable slip speed after the decrease, the brake force is increasedto the brake force level prior to the decrease. This is suitably performedcontinuously until the wheel brake 12 is no longer applied. lt may bedetermined if the driving wheel 6 is slipping in step c) by identifying thepresence of powertrain oscillations. lf there are no oscillations after thedecrease, the brake force may be further decreased. lf there are powertrainoscillations after the decrease, the brake force is increased to the brake forcelevel prior to the decrease.
    Figure 4 is a diagram of a version of a device 500. The control unit 30 and/orcomputer 32 described with reference to Fig. 1-Fig. 3 may in a versioncomprise the device 500. The term “link” refers herein to a communication linkwhich may be a physical connection such as an optoelectronic communicationline, or a non-physical connection such as a wireless connection, e.g. a radiolink or microwave link. The device 500 comprises a non-volatile memory 520, adata processing unit 510 and a read/write memory 550. The non-volatilememory 520 has a first memory element 530 in which a computer programme,e.g. an operating system, is stored for controlling the function of the device 500.The device 500 further comprises a bus controller, a serial communication port,I/O means, an A/D converter, a time and date input and transfer unit, an eventcounter and an interruption controller (not depicted). The non-volatile memory520 has also a second memory element 540. 17 There is provided a computer programme P which comprises routines for amethod for reducing powertrain osci|ations in a vehicle 1 according to theinvention. The computer programme P comprises routines for determining if ariving wheel 6 is slipping. The computer programme P comprises routines forapplying a wheel brake 12 such that a predetermined brake force is provided.
    The computer programme P comprises routines for decreasing the brake force.
    The computer programme P comprises routines for increasing the brake force.The computer programme P comprises routines for determining the presenceof powertrain oscillations. The programme P may be stored in an executabieform or in a compressed form in a memory 560 and/or in a read/write memory550.
    Where the data processing unit 510 is described as performing a certainfunction, it means that the data processing unit 510 effects a certain part of theprogramme stored in the memory 560 or a certain part of the programmestored in the read/write memory 550.
    The data processing device 510 can communicate with a data port 599 via adata bus 515. The non-vo|ati|e memory 520 is intended for communication withthe data processing unit 510 via a data bus 512. The separate memory 560 isintended to communicate with the data processing unit 510 via a data bus 511.The read/write memory 550 is adapted to communicating with the dataprocessing unit 510 via a data bus 514.
    When data are received on the data port 599, they are stored temporari|y inthe second memory element 540. When input data received have beentemporari|y stored, the data processing unit 510 is prepared to effect codeexecution as described above.
    Parts of the methods herein described may be effected by the device 500 bymeans of the data processing unit 510 which runs the programme stored in the 18 memory 560 or the read/write memory 550. When the device 500 runs the programme, methods herein described are executed.
    The foregoing description of the preferred embodiments of the presentinvention is provided for illustrative and descriptive purposes. lt is not intended to be exhaustive or to restrict the invention to the variants described. Many modifications and variations will obviously be apparent to one ski|ed in the art.
    The embodiments have been chosen and described in order best to explainthe principles of the invention and its practical applications and hence make itpossible for specialists to understand the invention for various embodimentsand with the various modifications appropriate to the intended use.
    权利要求:
    Claims (10)
    [1] 1. A method for reducing powertrain oscillations in a vehicle (1 ), wherein thepowertrain (3) of the vehicle (1) comprises an engine (2); a gearbox (4) with anoutput shaft (8); at least one drive shaft (10) connected to the output shaft (8)of the gearbox (4); at least one driving wheel (6) connected to the at least onedrive shaft (10); and at least one wheel brake (12) connected to the at leastone driving wheel (6), characterized by the steps to: a) determine if the at least one driving wheel (6) is slipping; and if so b) apply the wheel brake (12), such that a predetermined brake force is provided.
    [2] 2. A method according to claim 1, characterized in that the wheel brake (12) is applied in step b) such that the predetermined brake force is greater than the friction force between the slipping driving wheel (6) and the ground surface.
    [3] 3. A method according to claim 1 or 2, characterized in that the wheel brake(12) is applied in step b) such that the predetermined brake force is at leasttwice as large as the friction force between the driving wheel (6) and theground surface.
    [4] 4. A method according to any of the preceding claims, characterized in that itis determined if the at least one driving wheel (6) is slipping in step a) basedon the rotational speed of the driving wheel (6).
    [5] 5. A method according to any of the preceding claims, characterized in thefurther step to: c) gradually decrease the brake force to zero as long as the driving wheel (6) isnot slipping or is slipping with an acceptable slip speed while the vehicle is moving.
    [6] 6. A powertrain (3) of a vehicle (1), comprising an engine (2); a gearbox (4)with an output shaft (8); at least one drive shaft (10) connected to the output shaft (8) of the gearbox (4); at least one driving wheel (6) connected to the atleast one drive shaft (10); and at least one wheel brake (12) connected to theat least one driving wheel (6), characterized in that a control unit (30) isconnected to the at least one driving wheel (6) and the at least one wheelbrake (12), wherein the control unit (30) is adapted to determining if the atleast one driving wheel (6) is slipping and, if so, apply the wheel brake (12)such that a predetermined brake force is provided.
    [7] 7. A powertrain according to claim 6, characterized in that the control unit(30) is adapted to gradually decrease the brake force to zero as long as thedriving wheel (6) is not slipping or is slipping with an acceptable slip speed while the vehicle (1) is moving.
    [8] 8. A vehicle (1 ), characterized by a powertrain (3) according to any of the claims 6-7.
    [9] 9. A computer program (P), wherein said computer program comprisesprogramme code for causing an electronic control unit (30; 500) or a computer(32; 500) connected to the electronic control unit (30; 500) to perform the stepsaccording to any of the claims 1-5.
    [10] 10. A computer programme product comprising a programme code stored on acomputer-readable medium for performing the method steps according to anyof claims 1-5, when said computer programme is run on an electronic controlunit (30; 500) or a computer (32; 500) connected to the electronic control unit(30; 500).
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    同族专利:
    公开号 | 公开日
    SE539498C2|2017-10-03|
    DE102016005890A1|2016-11-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102008035556A1|2008-07-30|2010-02-04|Bayerische Motoren Werke Aktiengesellschaft|Controlling and/or regulating system for four-wheel driven motor vehicle, has control unit formed such that coupling torque is modulated when drive wheel vibration or drive strand vibration is detected by vibration detecting module|
    US8095288B2|2009-04-17|2012-01-10|Ford Global Technologies, Llc|Reducing oscillations in a motor vehicle driveline|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE1550624A|SE539498C2|2015-05-15|2015-05-15|A method for reducing powertrain oscillations|SE1550624A| SE539498C2|2015-05-15|2015-05-15|A method for reducing powertrain oscillations|
    DE102016005890.0A| DE102016005890A1|2015-05-15|2016-05-12|Method of reducing driveline vibration|
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