SE2050625A1

SE2050625A1 - Method and control arrangement in a vehicle approaching an uphill slope

Info

Publication number: SE2050625A1
Application number: SE2050625A
Authority: SE
Inventors: Erik Holma; Martin Jakobsson; Mikael Ögren; Mikael Alenius
Original assignee: Scania Cv Ab
Priority date: 2020-06-01
Filing date: 2020-06-01
Publication date: 2021-12-02
Also published as: DE102021112774A1

Abstract

A method and a control arrangement for controlling a vehicle are presented. The vehicle comprising:an internal combustion engine configured to generate a torque, and a cruise controller configured to control a speed of the vehicle (100). The method comprises, when the vehicle is in motion with the cruise controller activated and when an uphill section of a road in front of the vehicle is detected:reducing the speed of the vehicle from a first speed v1 to a second speed V2 prior to reaching the uphill section by reducing the initial torque tinit generated by the internal combustion engine to a first torque t1; and thereafterincreasing the speed of the vehicle from the second speed v2 to a third speed V3 by increasing the torque generated by the internal combustion engine to a second torque t2, wherein the second torque t2 is higher than the initial torque tinit.Hereby, the torque provided by the vehicle’s engine is optimized prior to the vehicle entering the uphill slope by controlling the vehicle's speed so that significant speed drop and a risk of power deficit in the uphill slope is avoided.

Description

METHOD AND CONTROL ARRANGEMENT IN A VEHICLE APPROACHING ANUPHILL SLOPE Technical field The invention relates to a method and a control arrangement for controlling an internalcombustion engine in a vehicle approaching an uphill slope. The invention also relatesto a computer program and a computer-readable medium and a vehicle comprising such a control arrangement.

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

Motor vehicles, such as cars, trucks and buses are nowadays often equipped withcruise controls controlling the vehicle to achieve e uniform predetermined vehiclespeed in e fuel-efficient manner. A general purpose for cruise control is to achieveconvenient running of the vehicle and also greater comfort for its driver.A driver of a vehicle with cruise control function usually sets a cruising speed es thespeed which lie/she wishes the vehicle to rnaintain until the cruise control function isfor eny reason deectiveted. The cruising speed may be selected based on e.g. apreferred time when the vehicle is to arrive at a final destination and/or to obtain fuelefficiency. For example, long-distance vehicles may be adapted for a typical cruisingspeed which may, depending on the region and/or type of road, be e.g. 80 km/h, 85km/h or 89 km/h. The cruising speed may be coordinated with other vehicles whentraveling in fuel efficient formations on motorvvays/highways e.g. in platooning vehicleformation. Maintaining a short distance to a leading vehicle, enables a vehicle in aplatooning formation to reduce an air resistance of the vehicle which may contribute toreduced fuel consumption. To keep the platooning formation intact/unaltered, thevehicles should preferably follow the movements of each other.

However, when driving in uphill road sections vehicles may experience speed drops ifa torque output from the vehicle's internal combustion engine is not large enough tomaintain an initial speed. Such speed drops may adversely affect time and fuelefficiency of the vehicle. For example, the vehicle may not be able to follow its timeschedule and/or no longer be able to follow a leading vehicle. Thus, maintaining arequired speed entails that the vehicle's speed is optimized for different driving scenarios and road topographies.

Summary lt is an objective of the present invention to provide methods and control arrangementfor mitigating or solving drawbacks of conventional solutions. ln particular an objectiveof the present invention is to provide a solution for fuel efficient driving in uphill slope without unnecessary loss of speed.

According to a first aspect of the invention, aforementioned and further objectives areachieved through a method for a control arrangement configured to control a vehicle, the vehicle comprising:an internal combustion engine configured to generate a torque, anda cruise controller configured to control a speed of the vehicle; wherein the method comprises when the vehicle is in motion with the cruise controlleractivated and when an uphill section of a road in front of the vehicle is detected: reducing the speed of the vehicle from a first speed to a second speedprior to reaching the uphill section by reducing the initial torque generated by the internal combustion engine to a first torque; and thereafter increasing the speed of the vehicle from the second speed to a third speedby increasing the torque generated by the internal combustion engine to a secondtorque, wherein the second torque is higher than the initial torque.

Hereby, the torque provided by the vehicle's engine is optimized prior to the vehicleentering the uphill slope by controlling the vehicle's speed so that significant speeddrop and a risk of power deficit in the uphill slope is avoided. Thus, the vehicle maymaintain a required speed in the uphill slope. Moreover, if the vehicle is equipped witha turbocharger, increasing the engine's torque prior to an uphill section enables a pressure to be built up in the turbocharger so that higher torque may be provided inthe uphill slope. ln that way increased fuel efficiency is obtained due to e.g. moreconsistent torque during the uphill slope. ln an embodiment of the invention, the second torque is generated by the internalcombustion engine when the vehicle reaches a position of the uphill section where adriving resistance for the vehicle equals or exceeds a maximum torque that may begenerated by the internal combustion engine.

Hereby, it may be assured that the engine's torque is optimized at a position where thevehicle speed and the engine's power is about to decrease. Optimizing the engine'storque may lead to reduced risk of speed drop in the uphill slope and may reduce theneed of a gear downshift. Thereby increased fuel efficiency is obtained. ln an embodiment of the invention, the second torque is the maximum torque that maybe generated by the internal combustion engine.

Hereby, a maximum power is provided by the vehicle engine and the risk of significantspeed decrease in the uphill slope is alleviated. ln an embodiment of the invention, the method further comprises: determining the second speed v2 prior to the reducing the speed of the vehicle based on at least one of:the first speed,the second torque,a weight of the vehicle,a current gear ratio of a transmission of the vehicle,a distance to the uphill section,an inclination of the uphill section, andan inclination of a road section in front of the vehicle before the uphill section.

Hereby, the second speed is determined in a reliable way such that the engine's torque may be optimized at a required position. ln an embodiment of the invention, the method further comprises when the vehicle istrailing a leading vehicle determining the second speed further based on at least oneof: a distance to the leading vehicle, anda speed of the leading vehicle.

Hereby, the speed of the vehicle can be controlled such that a risk of unforeseendecrease of the speed of the vehicle, due to reduced speed of a leading vehicle ismitigated. Moreover, the risk of losing the leading vehicle is reduced. ln an embodiment of the invention, the method further comprises determining a first position where the reducing of the speed is commenced based on the second speed.

Hereby, reducing the vehicle speed by applying a preferred speed reduction strategybased on the first position may be enabled which may lead to an increased fuelefficiency. ln an embodiment of the invention, the reducing of the speed is commenced at the firstposition.

Hereby the vehicle speed can be reduced such that the engine's torque may beoptimized at a required position. ln an embodiment of the invention, the method further comprises determining a secondposition where the increasing of the speed is commenced based on the second speed.

Hereby, the vehicle's engine torque may be optimized at a required position. ln an embodiment of the invention, the increasing of the speed is commenced at thesecond position.

Hereby the vehicle speed can be controlled so that the engine's torque may beoptimized at a required position. ln an embodiment of the invention, the uphill section has at least one of:a first inclination, a length, and a driving resistance equal or exceeding a maximum torque that may be generated by the internal combustion engine.Hereby, a significant speed reduction in the uphill section is avoided.ln an embodiment of the invention, the uphill section has an expected reduction of the speed of the vehicle exceeding a speed reduction threshold value.Hereby, a significant speed reduction in the uphill section is avoided. ln an embodiment of the invention, the vehicle further comprises a turbochargerconfigured to increase a power output of the internal combustion engine, and further configured to build-up a pressure such that an additional torque is generated by the combustion engine.Hereby, a significant speed reduction in the uphill section is avoided.

According to a second aspect, the invention relates to a control arrangement forcontrolling a vehicle, the vehicle comprising: an internal combustion engine configured to generate a torque, anda cruise controller configured to control a speed of the vehicle; wherein the control arrangement is configured to when the vehicle is in motion with thecruise controller activated and when an uphill section of a road in front of the vehicle isdetected: reduce the speed of the vehicle from a first speed to a second speed prior toreaching the uphill section by reducing the torque generated by the internal combustionengine to a first torque; and thereafter increase the speed of the vehicle from the second speed to a third speed by increasingthe torque generated by the internal combustion engine to a second torque, whereinthe second torque is higher than the first torque. lt will be appreciated that all the embodiments described for the method aspects of theinvention are applicable also to at least one of the control arrangement aspects of theinvention. Thus, all the embodiments described for the method aspects of the invention may be performed by the control arrangement, which may also be a control device, i.e.a device. The control arrangement and its embodiments have advantagescorresponding to the advantages mentioned above for the methods and theirembodiments.

According to a third aspect of the invention, aforementioned and further objectives are achieved through a vehicle comprising the control arrangement of the second aspect.

According to a fourth aspect, the invention relates to a computer program comprisinginstructions which, when the program is executed by a computer, cause the computerto carry out the method according to the first aspect.

According to a fifth aspect, the invention relates to a computer-readable mediumcomprising instructions which, when executed by a computer, cause the computer tocarry out the method according to the first aspect.

Brief description of the drawings 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 schematically illustrates a vehicle driving through a route and a corresponding speed of the vehicle over a time.

Figure 2 shows an example vehicle, in which embodiments of the present inventionmay be implemented, Figure 3 shows a flow chart for methods of a vehicle according to some embodiments of the present the invention, Figure 4 illustrates a speed variation of a vehicle driving through a route according tosome embodiments of the present the invention, Figure 5 shows a flow chart of method 200 according to an embodiment of the invenüon,and Figure 6 shows a control arrangement, in which a method according to any one of theherein described embodiments may be implemented.

Detailed description A vehicle entering an uphill road section or slope may experience several problems,depending on the situation. For example, an initial speed of the vehicle may, afterentering the slope, drop substantially if a torque output from the vehicle's internalcombustion engine is not large enough to maintain the initial speed. lt the vehicle isequipped with a turbocharger, the internal combustion engine's efficiency may bemomentarily increased once the turbocharger's pressure is built up. This is achievedby forcing an extra compressed air into a combustion chamber of the engine enablingthe engine to use more fuel. However, in some situations, e.g. when the vehicle isdriving close behind a leading vehicle, driving at speed limiter or driving in overspeed,the power demand from the engine may not be high enough to fully charge the vehicle'sturbo before entering the slope or deliver a torque needed for the uphill slope.Moreover, if the speed of the leading vehicle decreases in the start of the uphill slope,the vehicle may be forced to brake due to too short distance towards the leadingvehicle leading to decreased power and torque when entering the uphill slope.

Figure 1 schematically illustrates a vehicle driving with activated cruise controllerthrough a route including an uphill slope 510 and a corresponding speed v of thevehicle over a time T. Prior entering the uphill slope 510, i.e. prior to time instance T1,the vehicle is driving with a speed v1. Due to the driving situation, the vehicle's engineis not able to generate a maximum torque. The vehicle may be e.g. driving at speedlimiter or trailing a leading vehicle at a constant torque demand. The vehicle may beequipped with a turbocharger, but the turbocharger's pressure may not be built up,depending on the driving situation, until the torque demand is increased at timeinstance T1. At time instance T1 the vehicle enters the uphill slope. The engine torquedemand may increase but, in case the uphill slope is steep, the engine may not be ableto deliver the torque needed to maintain the speed v1 in the uphill slope which mayresult in a speed drop. However, due to the increased torque demand, the pressure inthe vehicle's turbocharger is built up between the time instance T1 and the timeinstance T2. At the time instance Tz, the pressure in the turbocharged is loaded andthe combustion engine's efficiency is increased. Thereby an additional torque isprovided resulting in increased vehicle speed and slower speed drop in the rest of the uphill slope. At the time instance Ta, the uphill slope ends, and the vehicle is able to accelerate to a desired speed. lt the vehicle is driving through the route behind a leading vehicle, the significant speeddrop in the uphill slope may result in the distance between the vehicle and the leadingvehicle becoming larger than preferred, for example when the vehicle and the leadingvehicle are driving in a platooning formation. Such too long distances between vehiclesmay have a negative effect on the fuel consumption. Maintaining a short distance tothe leading vehicle may help reducing the air resistance of the vehicle and may contribute to reduced fuel consumption. lt is therefore an objective of the present invention to provide a method and a controlarrangement for controlling a vehicle entering an uphill slope such that these problemsare at least partly solved.

Figure 2, which will be used to explain the herein presented embodiments,schematically shows an exemplary vehicle 100, such as a truck carrying a heavycargo/load. The embodiments are, however, not limited for use in vehicles as thevehicle shown in Figure 2, but may also be used in lighter vehicles, such as smallertrucks, cars, and other vehicles.

A vehicle 100, as shown schematically in Figure 2, comprises a pair of drive wheels111, 112 and at least one other pair of wheels 113, 114. The vehicle furthermorecomprises a driveline/drivetrain 110 configured to transfer a torque between at leastone power source 101, such as e.g. an engine, and the drive wheels 111, 112.According to the present invention, the at least one power source 101 includes at leasta combustion engine. The vehicle 100 may also include a turbocharger unit 119 suchas a VGT (variable geometry turbocharger) unit, or a turbo unit with a waste gatearranged for compressing the air supplied for combustion in the combustion engine toincrease the power of the engine.

The at least one power source 101 is for example in a customary fashion, via an outputshaft 102 of the engine 101, connected to a clutch 106, and via the clutch also to agearbox 103. The clutch 106 can be a manually or automatically controlled clutch in aknown manner, and the gearbox 103 can be arranged to be changed by the driver of the vehicle 100 or automatically by the control system of the vehicle. The torque provided by the engine 101 is provided to an input shaft 109 of the gearbox 103. Apropeller shaft 107, connected to an output shaft of the gearbox 103, drives the drivewheels 111, 112 via a central gear 108, such as e.g. a customary differential, and driveshafts 104, 105 connected with the central gear 108. Also, one or more electricalmachine may be arranged essentially anywhere along the driveline 110, as long astorque is provided to one or more of the wheels 111, 112, 113, 114, e.g. adjacent toone or more of the wheels 111, 112, 113, 114, as is understood by a skilled person.

The vehicle 100 also may include at least one braking arrangement 151, 152, 153,154, for example one braking arrangement 151, 152, 153, 154 arranged at each oneof the wheels of the vehicle. The at least one braking arrangement 151, 152, 153, 154may be included in at least one braking system 150. Braking of the vehicle 100, whichmay result in a retardation of the vehicle 100, by use of the at least one brakingarrangement 151, 152, 153, 154 may be achieved in a number of well-known ways.The at least one braking system 150 may also include one or more additional brakingdevices 155, for example one or more additional braking devices acting on the driveline110, such as a retarder, and/or an exhaust brake device. The at least one brakingsystem 150, including the at least one braking arrangement 151, 152, 153, 154 and/orthe at least one additional braking device 155 may be controlled by at least one control arrangement 160.

The control arrangement 160 may be distributed on several control units configured tocontrol different parts of the vehicle 100. The control arrangement 160 may e.g. includea speed-reducing unit 161 and a speed-increasing unit 162 arranged for performingthe method steps of the disclosed invention as is explained further on. The controlarrangement 160 and/or another control arrangement may further be configured forcontrolling one or more of the at least one power source 101, the clutch 106, thegearbox 103, and/or any other units/devices/entities of the vehicle. However, in figure2, only the units/devices/entities of the vehicle useful for understanding the presentinvention are illustrated. The control arrangement 160 will be described in further detail in Figure 6.

The vehicle 100 may further include one or more sensors 175, e.g. at least one cameraand/or at least one pressure sensor, located at suitable positions within the vehicle100. Further, the vehicle 100 may comprise a positioning system/unit 180. The positioning unit 180 may be based on a satellite navigation system such as theNavigation Signal Timing and Ranging (Navstar), Global Positioning System (GPS),Differential GPS (DGPS), Galileo, GLONASS, or the like. Thus, the positioning unit180 may comprise a GPS receiver.

The vehicle 100 may further include at least one communication device 170 arrangedfor communication with at least one entity 190 external to the vehicle 100, such as e.g.an infrastructure entity, a communication entity of another vehicle, an external server,and/or a positioning information entity. Correspondingly, the at least onecommunication device 170 may be a vehicle-to-vehicle (V2V) communication device,a vehicle-to-infrastructure (V2l) communication device, a vehicle-to-everything (V2X)communication device, and/or a wireless communication device such thatcommunication between the vehicle and the at least one external entity 190 is achieved/provided.

The proposed solution will now be described with reference to a method 200 disclosedin Figure 3 and the vehicle 100 disclosed in Figure 2. Figure 3 illustrates a flow chartof the method 200 for a control arrangement 160 configured to control a vehicle 100,such as the vehicle disclosed in Figure 2. The vehicle 100 comprises an internalcombustion engine 101 configured to generate a torque, and a cruise controller 162configured to control a speed of the vehicle 100.

The method 200 comprising when the vehicle 100 is in motion with the cruise controller162 activated and when an uphill section 510 of a road in front of the vehicle 100 isdetected: - in step 210 in Figure 3, reducing 210 the speed of the vehicle 100 from a firstspeed v1 to a second speed vz prior to reaching the uphill section 510 byreducing the initial torque tinii generated by the internal combustion engine 101to a first torque t1; and thereafter - in step 220 in Figure 3, increasing 220 the speed of the vehicle 100 from thesecond speed v2 to a third speed vs by increasing the torque generated by theinternal combustion engine 101 to a second torque t2, wherein the secondtorque t2 is higher than the initial torque tarm. ln other words, the method 200 may be executed when an uphill section 510 of a roadin front of the vehicle 100 is detected. Generally, detecting an uphill section 510 of aroad in front to the vehicle 100 may be done by means of one or more sensors 175which may be included in the vehicle 100 e.g. one or more camera, one or more radarequipment and/or a positioning system/unit, such as GPS. Moreover, the uphill section510 may be detected based on information provided by at least one second vehicle,e.g. by V2V communication, and/or by an infrastructure entity, e.g. by V2|communication, be obtained based on radar information, on camera information, onpositioning information stored previously in the vehicle 100 and, on information obtained from traffic systems related to the road section.

For example, information associated with a position of the vehicle 100 may be providedby the positioning system in the vehicle 100. Map associated information e.g. fromdigital maps may, for example include topology information of an electronic map.Typica||y, positioning information may be used for positioning the vehicle 100 on thecorrect location of a digital map, whereby it may be detected that the vehicle 100 is approaching an uphill slope 510.

Once an uphill section 510 is detected, the speed of the vehicle is controlled accordingto step 210 and step 220 in Figure 2.

By the use of the presented method the speed of the vehicle 100 in controlled suchthat the torque provided by the vehicle's engine when the vehicle 100 is entering theuphill slope is optimized. Moreover, if the vehicle 100 is equipped with a turbocharger,increasing the engine's torque prior to the vehicle 100 entering the uphill section,enables a pressure to be built up in the turbocharger so that the engine's efficiency isadditionally increased. ln that way increased fuel efficiency is obtained due to e.g. more consistent torque during the uphill slope.

Now turning to Figure 4, which illustrates a driving scenario, similar to the oneillustrated in Figure 1, where the aspect of method 200 illustrated in Figure 3 and furtherembodiments of the method may be implemented. The vehicle 100 illustrated in Figure4 is driving, with an activated cruise controller 162, through a route including an uphi||slope 510. The uphill slope may have an inclination oi, which may or may not vary. For example, the road section 500 may include a first portion with a first inclination, a second portion with a second inclination, etc. ln an embodiment, the uphill section 510may have least one of a first inclination on, a length, and a driving resistance equal orexceeding a maximum torque that may be generated by the internal combustionengine 101. Thus the speed of the vehicle 100 driving in the uphill slope 510 at amaximum engine torque will decrease. ln an embodiment, the uphill section 510 mayhave an expected reduction of the speed of the vehicle 100 exceeding a speedreduction threshold value Avih. Thus, if the expected reduction of the speed of thevehicle 100 in the uphill section 510 exceeds the speed reduction threshold value Avihthe method 200 is executed. The speed reduction threshold value Avih may be a presetvalue and/or may depend on the driving situation and/or on the length of the uphillslope 510. The speed reduction threshold value Avih may depend on a time delay forthe vehicle caused by the speed reduction in the uphill slope. For example, a speedreduction of 1km/h in a 2 min slope leads to an approximal loss of 40 meters whichcorresponds to a time loss of ~1.6 seconds. ln a non-limiting example, the speedreduction threshold value Avih may be 1km/h for longer slopes e.g. slopes exceedinga length of 1km. The expected reduction of the speed of the vehicle 100 in the uphillslope may be determined according to conventional methods based on at least themaximum torque of the vehicles engine when using a current gear ratio of atransmission of the vehicle 100, a weight of the vehicle 100 and the first inclination onof the uphill section 510. For example, by using Newton's laws of motion the forcesacting on the vehicle 100 may be estimated for a situation when the vehicle 100 isdriving is driving in the uphill slope 510 when a maximum engine torque is applied. ln such way an expected speed reduction in the uphill slope may be estimated.

The first inclination on of the uphill section 510 may easily be determined based e.g.on map information on GPS information, on radar information, on camera information,on information from another vehicle, on positioning-related and road gradientinformation stored previously in the vehicle 100, and/or on information obtained fromtraffic systems related to said road section. ln systems where information exchangebetween vehicles is used, the first inclination on estimated by a vehicle 100 may alsobe provided to other vehicles, either directly or via an intermediate unit, such as a database or similar. ln other words, the hereby presented method may, in an embodiment be applied if theexpected reduction of the speed of the vehicle 100 equal or exceeds the speed reduction threshold value Avih.

The solid speed curve in Figure 4 illustrates the speed variation when method 200 isnot applied as explained with reference to Figure 1. The dotted speed curve in Figure4 illustrates the speed variation of the vehicle 100 according to an embodiment of theinvention. As previously explained, with reference to Figure 1, prior entering the uphillslope 510, i.e. prior to time instance Ta in Figure 4, the vehicle 100 is driving with a first speed v1. The vehicle 100 may or may not be trailing a leading vehicle 180.

Upon detecting an uphill section 510 of a road in front of the vehicle 100, the speed ofthe vehicle 100 is, between time instance T1 and time instance Tz in Figure 4, reducedfrom a first speed v1 to a second speed vz prior to reaching the uphill section 510 attime instance Ta. The speed reduction may e.g. be commenced at a first position d1.The speed of the vehicle 100 may be reduced by reducing an initial torque trimgenerated by the vehicle's internal combustion engine 101 to a first torque t1, whichmay be done in a number of different ways as will be explained further with referenceto Figure 5. Between time instance T2 and time instance Ta, the speed of the vehicle100 is increased 220 from the second speed v2 to a third speed va. The speed increasemay e.g. be commenced at a second position d2. The speed may be increased byincreasing the torque generated by the internal combustion engine 101 to a secondtorque t2, wherein the second torque tz is higher than the initial torque trim. lncreasingthe torque may be done by e.g. increasing a request of positive engine torque. Notethat the third speed va is in Figure 4 illustrated as being higher than the first speed v1.This is not necessarily the case. The third speed va may be higher than or equal to the first speed v1.

Thus, by controlling the speed of the vehicle 100 prior entering the uphill slope 510,the torque generated by the combustion engine of the vehicle at time instance Ta inFigure 4, when the vehicle 100 enters the uphill slope is higher than the torqueaccording to prior art. The speed of the vehicle 100 in the uphill slope, i.e. between thetime instance Ta and T4 in Figure 4 may still drop, but the speed drop will be lower throughout the entire slope 510. ln an embodiment, the second torque t2 is generated by the internal combustion engine101 when the vehicle 100 reaches a position of the uphill section 510 where a drivingresistance for the vehicle 100 equals or exceeds a maximum torque that may be generated by the internal combustion engine 101.

The vehicle 100 driving in the uphill slope 510 is exposed to a forward traction forceresulting from the torque generated by the vehicle's internal combustion engine 101and a resistance force resulting from e.g. the vehicle's weight and the inclination of theuphill slope 510, directed in the downhill direction acting to decelerate the vehicle 100.Vehicle 100 driving in an uphill slope where the resistance force equals a maximumforvvard traction force resulting from a maximum torque generated by the vehicle'sinternal combustion engine 101 is able to maintain a desired speed in the slopeHowever, if the resistance force exceeds the maximum forvvard traction force thevehicle 100 will decelerate. Optimizing the engine's torque according to the method200 of the invention may lead to higher speed during the uphill slope and may reduce the need of a gear downshift resulting in increased fuel efficiency. ln addition to the method steps 210 - 220 described with reference to Figure 3 themethod 200 may in an embodiment, comprise optional steps 202 - 206. Figure 5 shows a flow chart of method 200 according to an embodiment of the invention. lt should be noted that the method steps illustrated in Figure 5 and described hereindo not necessarily have to be executed in the order illustrated in Figure 5. The stepsmay essentially be executed in any suitable order, as long as the physical requirementsand the information needed to execute each method step is available when the step is executed. ln step 202 in Figure 5, preceding the previously described step 210 where the speedof the vehicle 100 is reduced from a first speed v1 to a second speed vz, a secondspeed vz is determined. Determining the second speed vz may, according to anembodiment, be done based on at least one of the first speed vi, the second torque tz,a weight of the vehicle 100, a current gear ratio of a transmission of the vehicle 100, adistance to the uphill section 510, an inclination of the uphill section 510, and aninclination of a road section in front of the vehicle 100 before the uphill section 510.

Determining the second speed v2 may e.g. be done according to conventional methodsusing e.g. Newton's laws of motion to estimate the manner in which the speed of thevehicle 100 will change when driving through an upcoming section of the road, wheree.g. different speed reduction strategies, such as reduced request of positive enginetorque, dragging, freewheeling etc., may be evaluated where the reduction of thespeed of the vehicle 100 is followed by an increase of the speed of the vehicle 100such that a second torque t2 is obtained when reaching the uphill slope.

The reduced request of positive engine torque entails that the force driving in thedirection of travel, emitted by the combustion engine 101 via the driving wheels 111,112, is reduced, e.g. through reduced fuel injection into the engine, which reduces thefuel consumption. Dragging means driving the vehicle with a closed powertrain i.e. withthe combustion engine connected to the vehicle's driving wheels, at the same time asthe fuel injection to the combustion engine is closed. One advantage with this type ofmeasure is, that since the fuel injection to the combustion engine is closed, thecombustion engine's consumption is equal to zero. This measure does, however, alsoentail that the combustion engine 101 will be driven by the vehicle's driving wheels viathe powertrain, and so-called "dragging" is thus achieved, whereat the combustionengine's internal losses give rise to a braking action, i.e. engine braking of the vehicleto achieve a speed reduction. Freewheeling means that the vehicle's combustionengine 101 is disconnected from the driving wheels 111, 112, i.e. the powertrain isopened. This disconnection by opening the power train may for example be achievedby putting the vehicles gearbox 103 into neutral or by opening the clutch 106.

The vehicle internal parameters like weight of the vehicle 100 and the current gear ratiomay be obtained from the vehicle's control system via one or more communicationbuses linking the control arrangement 150 with various components and controllers located on the vehicle 100.As previously described, the second torque t2 is higher than the initial torque tarm.

According to one example, the second torque t2, in an embodiment, is the maximumtorque that may be generated by the internal combustion engine 101 for current gearratio of a transmission of the vehicle 100. ln that way, the vehicle 100 may obtain a highest possible speed in the uphill slope and a need of downshifting gears may thus be avoided.

The distance to the uphill section 510 can be determined based on a number of knownways all included within the scope of the invention. For example, the distance to theuphill section 510 can be determined by means of distance measurements performedby at least one onboard sensor means 175. The distance to the uphill section 510 mayin another example be determined e.g. based on map data. Moreover, the distancecan be determined by at least one other vehicle 180 in front the vehicle 100 andcommunicated to the vehicle 100 using e.g. V2V communication. The distance canalso be determined by a nearby infrastructure device and communicated to the vehicle100 using e.g. V2l communication.

The inclination of the uphill section as well as the inclination of a road section in frontof the vehicle 100 before the uphill section 510 may, as previously described bedetermined based on, e.g., map data in combination with positioning information. Theinclination of the road may also be obtained e.g. based on an engine torque in thevehicle 100, on an acceleration of the vehicle 100, on an accelerometer, on GPSinformation, on radar information, on camera information, on information from at leastone other vehicle 180, on positioning-related and road gradient information storedpreviously in the vehicle 100, and/or on information obtained from traffic systems related to said road section or in any other, known in the art method. ln an embodiment, when the vehicle 100 is trailing a leading vehicle 180 thedetermining in step 202 in Figure 5 the second speed v2 may further be based on atleast a distance to the leading vehicle 180, and a speed of the leading vehicle 180. ln one example, the second speed vz may be determined such that the distance to theleading vehicle is increased prior to the uphill slope 510 if the distance is determinedtoo short.

There may be different reasons for increasing the distance to the leading vehicle.

For example, the distance between the vehicle 100 and the leading vehicle 180 maybe kept short e.g. to obtain a fuel-efficient driving by reducing the air resistance forceacting on the vehicle 100. ln these situations, the speed of the vehicle 100 may be controlled in dependence of the speed of the leading vehicle 180. For example, if the speed of the leading vehicle 180 is unexpectedly reduced, the vehicle 100 may beforced to reduce its speed as well to maintain a safe distance to the leading vehicle180. ln this situation, applying the method 200 to increase the vehicles engine torquemay not be possible due to too short a distance to the leading vehicle 180. An increaseof the distance to the leading vehicle 180 prior to the uphill slope 510 is reached mayenable the vehicle 100 to subsequently optimize the engine torque by increasing thespeed and building up the engine torque before reaching, or at, the beginning of the uphill slope 150.

According to another example, the vehicle 100 may be driving behind a leading vehicle180 which is less powerful and/or that has not increased engine torque in advance,thereby causing the leading vehicle to lose speed in the uphill slope 510. lncreasingthe distance to the leading vehicle 180 prior to entering the uphill slope 510 maymitigate the risk of the vehicle 100 catching up with the leading vehicle and lose speed and momentum in the uphill slope 510 also in such situations.

According to one example, the distance to the leading vehicle may be increased abovea predetermined distance threshold. ln a non-limiting example the distance may beincreased to keep at least a recommended time slot to the leading vehicle 180 priorthe vehicle 100 reaches the uphill slope 510. Under normal driving conditions arecommended time slot to a vehicle in front could be between e.g. 1.5 and 4 secondsdepending on the speed of the leading vehicle 180. For example, if the speed of theleading vehicle 180 prior entering the uphill slope 510 is 85km/h, the distance to theleading vehicle may be increased to at least 70 meters, which corresponds to a time slot of 3 seconds.

The distance to the leading vehicle 180 and the speed of the leading vehicle 180 maye.g. be determined based on measurements performed by at least one onboard sensormeans 175, measuring the distance to the leading vehicle 180 and the speed of theleading vehicle 180. The distance to the leading vehicle 180 and the speed of theleading vehicle 180 may be determined by the leading vehicle 180 and communicated to the vehicle 100 using e.g. V2V communication. ln step 204 in Figure 5, according to an embodiment a first position d1 is determined, wherein the first position d1 is a position where the reducing 210 of the speed of the vehicle 100 is commenced. The determining of the first position d1 may be based on the second speed vz. ln step 210 in Figure 5, as described with reference to Figure 3, the speed of the vehicle100 is reduced from a first speed v1 to a second speed vz prior to reaching the uphillsection 510 by reducing the initial torque tinii generated by the internal combustionengine 101 to a first torque t1. ln an embodiment, the reducing the speed of the vehicle100 is commenced at the first position d1.

Reducing the speed of the vehicle 100 from the first speed v1 to the second speed vzmay e.g. be achieved within a deceleration distance i.e. a distance from the timeinstance when the vehicle 100 starts to decelerate to the time instance when thedeceleration is completed, where the deceleration distance may depend on e.g. aspeed reduction strategy, an inclination of the road section in front of the vehicle 100before the uphill section 510 i.e. before the position d3 in Figure 4, a weight of the vehicle 100, to mention a few.

Reducing of the speed of the vehicle 100 from the first speed v1 to the second speedvz may be done in a number ofdifferent ways, i.e. as mentioned before different speedreduction strategies may be applied. For example, the speed of the vehicle 100 maybe reduced by reducing a request of positive engine torque, with the help of enginedragging or by freewheeling.

Choosing a speed reduction strategy may be based on the inclination of the roadsection in front of the vehicle 100 before the uphill section 510. For example, reducingthe vehicle speed by reducing the request of positive engine torque, with the help ofengine dragging or by freewheeling may be done if the road section in front of thevehicle 100 before the uphill section 510 is an uphill slope, a level slope or very gentledownhill slope to achieve the required reduction in speed. ln case the road section infront of the vehicle before the uphill section 510 is a steep downhill slope, speedreduction by means of wheel brakes 151-154 might become necessary. Furthermore,a speed reduction strategy may be selected based on fuel consumption such thatspeed reduction strategy resulting in a lowest possible fuel consumption is selected. Aspeed reduction strategy may, according to another example, be selected based on speed profile simulations as will be explained further.

The deceleration distance may e.g. be determined by simulating a speed profile of thevehicle 100. Such simulations may be performed in a large number of ways. Forexample, taking into account the inclination of the road section in front of the vehicle100 before the uphill section 510, the weight of the vehicle 100, the required speedreduction and increase to achieve a second engine torque prior to entering the uphillslope 510, a simulating of the speed profile of the vehicle 100 can be made for eachof the different speed reduction strategies. From the speed profile simulations adeceleration distance for each of the different speed reduction strategies may beobtained.

By determining the deceleration distance, the first position d1 where the reducing 210of the speed is commenced may be determined. For example, the first position d1 maybe located at least a deceleration distance for the applied speed reduction strategyprior to the second position d2. ln step 212 in Figure 5, according to an embodiment a second position d2, where theincreasing 220 of the speed is commenced, is determined. The determining of thesecond position d2 may be based on the second speed v2. Thus, a distance to increasethe speed of the vehicle 100 from a second speed v2 to a third speed vs by increasingthe engine torque from a first torque t1 to a second torque tz may be determined. Suchdistance may e.g. depend on the vehicle's internal combustion engine type.

Different internal combustion engines have different response times for building uptorque and deliver a target engine torque according to a torque request. A responsetime for torque build-up may be defined as a time period between a torque requesttime point, in which a change of engine torque is requested, and a performing timepoint, in which the change of engine torque is actually obtained.

For an engine working according to an Otto cycle, a specific ratio for the mixture of fueland air in the engine cylinders is needed in order to achieve a combustion of themixture in the cylinders. Also, the electric spark used for ignition of the mixture shoulddeliver the spark at the exact right time instant in order to provide a combustion. Thus,the engine torque, which is provided to the clutch, depends both on the timing of theignition spark and on the ratio between fuel and air. Therefore, the engine torque being provided to the powertrain is related to the response time for the ignition system and on the response time for the air input system. Also, the clutch system has a responsetime impacting the response time for providing a requested engine torque. Theresponse time for providing a requested engine torque may be around 10s for an Otto engine.

With regard to diesel engine on the other hand the fuel ignites on its own due to highcompression of the fuel/air and no electric spark is used. Thus, the response time forproviding a requested engine torque is shorter than for an Otto engine and may bearound 5s.

Determining the second position d2 where the increasing the speed is commencedmay e.g. be done according to conventional methods taking into account the requiredspeed increase from the second speed v2 to the third speed v3, the required torqueincrease from a first torque t1 to a second torque t2, the vehicle internal engine'sresponse time for providing a requested engine torque, the weight of the vehicle 100and/or an inclination of the road section in front of the vehicle 100 before the uphillsection 510. For example, by using Newton's laws of motion the forces acting on thevehicle 100 may be predicted for a situation when the vehicle 100 is driving throughthe upcoming road section before the uphill section 510 such that the speed of thevehicle 100 is increased from a second speed vz to a third speed vz and a secondengine torque t2 is provided prior to the uphill slope 510. ln such way an accelerationdistance required for the vehicle 100 to achieve the third speed v3 and the secondengine torque prior to the uphill slope may be determined. The second position d2where the increasing 220 of the speed is commenced may be located at least anacceleration distance prior to the location where the uphill section 510 starts. ln step 220 in Figure 5, as described with reference to Figure 3, the speed of the vehicle100 is increased from the second speed v2 to a third speed vs prior to reaching theuphill section 510 by increasing the torque generated by the internal combustionengine 101 to a second torque t2, wherein the second torque t2 is higher than the initialtorque tinii. ln an embodiment, the increasing 210 of the speed is commenced at thesecond position d2. ln an embodiment, the vehicle 100 may further comprise a turbocharger 119. The turbocharger may be configured to increase a power output of the internal combustion engine 101. The turbocharger 119 may further be configured to build-up a pressuresuch that an additional torque tq is generated by the combustion engine 101. ln oneexample, the pressure may be built up such that the additional torque tq is generatedprior to the vehicle 100 entering the uphill slope 510.

As previously mentioned, the power output of the internal combustion engine 101 maybe increased by compressing the combustion air in order to supply a greater air massto the combustion chamber for combustion. By supplying a greater air mass acorrespondingly larger amount of fuel can be supplied resulting in a higher powerdevelopment in the engine and generation of additional torque.

Such compression ofthe combustion air can be achieved e.g. by building up a pressurein a turbocharger 119, such as a VGT (variable geometry turbocharger) unit, or aturbocharger with a waste gate. The pressure in the turbocharger 119 may be built upby a turbine driven by exhaust gas. The amount of exhaust gas produced by the engineresults in a response time for building up a turbo pressure required for generation of arequired torque.

For example, it can take several seconds before the desired turbo pressure managesto be built up, with a corresponding delay until full torque can be developed by the internal combustion engine, and thus also a delay in the desired acceleration.

Building up the pressure in the turbocharger 119 such that the additional torque tq isgenerated prior to the vehicle 100 entering the uphill slope 510 may be done when thespeed of the vehicle 100 is increased from the second speed v2 to the third speed vsin step 220 with reference to as described with reference to Figure 3. Thus thedetermining of the second position d2 where the increasing 220 of the speed iscommenced may be based on the response time in the turbocharger 199 for buildingup a turbo pressure required for generation of the second torque t2.

According to an aspect of the invention, a control arrangement 160 for controlling a vehicle 100 is presented wherein the vehicle 100 comprises:an internal combustion engine 101 configured to generate a torque, and a cruise controller 162 configured to control a speed of the vehicle 100.

The control arrangement 160 includes means 161 arranged for, when the vehicle 100is in motion with the cruise controller 162 activated and when an uphill section 510 ofa road in front of the vehicle 100 is detected, reducing 210 the speed of the vehicle 100from a first speed v1 to a second speed vz prior to reaching the uphill section 510 byreducing the torque generated by the internal combustion engine 101 to a first torquet1.

The control arrangement 160 further includes means 162 arranged for thereafterincreasing 220 the speed of the vehicle 100 from the second speed vz to a third speedvs by increasing the torque generated by the internal combustion engine 101 to a second torque t2, wherein the second torque tz is higher than the first torque t1.

The control arrangement 160, e.g. a device or a control device, according to theinvention may be arranged for performing all of the above, in the claims, and in theherein described embodiments method steps. The control arrangement 160 is hereby provided with the above described advantages for each respective embodiment.The invention is also related to a vehicle 100 including the control arrangement 160.

Now turning to Figure 7 which illustrates the control arrangement 600/160, which maycorrespond to or may include one or more of the above-mentioned control units 161 -162 i.e. the control units performing the method steps of the disclosed invention. Thecontrol arrangement 600/160 comprises a computing unit 601, which can beconstituted by essentially any suitable type of processor or microcomputer, e.g. acircuit for digital signal processing (Digital Signal Processor, DSP), or a circuit havinga predetermined specific function (Application Specific Integrated Circuit, ASIC). Thecomputing unit 601 is connected to a memory unit 602 arranged in the controlarrangement 600/160, which memory unit provides the computing unit 601 with, e.g.,the stored program code and/or the stored data which the computing unit 601 requiresto be able to perform computations. The computing unit 601 is also arranged to store partial or final results of computations in the memory unit 602. ln addition, the control arrangement 600/160 is provided with devices 611, 612, 613,614 for receiving and transmitting input and output signals. These input and outputsignals can contain waveforms, impulses, or other attributes which, by the devices 611, 613 for the reception of input signals, can be detected as information and can be converted into signals which can be processed by the computing unit 601. Thesesignals are then made available to the computing unit 601. The devices 612, 614 forthe transmission of output signals are arranged to convert signals received from thecomputing unit 601 in order to create output signals by, e.g., modulating the signals,which can be transmitted to other parts of and/or systems in the vehicle 100.

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 skilled inthe art will appreciate that the above-stated computer can be constituted by thecomputing unit 601 and that the above- stated memory can be constituted by thememory unit 602.

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 control unit.Vehicles of the shown type thus often comprise significantly more control units thanare shown in Figures 1 and 5, which is well known to the person skilled in the art withinthis technical field. ln a shown embodiment, the invention may be implemented by the one or more abovementioned control units 161 and 162. The invention can also, however, beimplemented wholly or partially in one or more other control units already in the vehicle100, or in some control unit dedicated to the invention.

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

The one or more control units 161 and 162 are in Figure 1 illustrated as separate units.These units may, however, be logically separated but physically implemented in thesame unit or can be both logically and physically arranged together. These units may e.g. correspond to groups of instructions, which can be in the form of programming code, that are input into, and are utilized by a processor/computing unit 601 when the units are active and/or are utilized for performing its method step, respectively.

The person skilled in the art will appreciate that a the herein described embodimentsfor downshifting gears in an uphill slope may also be implemented in a computerprogram, which, when it is executed in a computer, instructs the computer to executethe method. The computer program is usually constituted by a computer programproduct 603 stored on a non-transitory/non-volatile digital storage medium, in whichthe computer program is incorporated in the computer-readable medium of thecomputer program product. The computer-readable medium comprises a suitablememory, such as, e.g.: ROM (Read-Only Memory), PROM (Programmable Read-OnlyMemory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically ErasablePROM), a hard disk unit, etc.

The invention is not limited to the above described embodiments. lnstead, the inventionrelates to, and encompasses all different embodiments being included within the scopeof the independent claims.

Claims

1. Method (200) for a control arrangement (160) configured to control a vehicle (100),the vehicle (100) comprising: an internal combustion engine (101) configured to generate a torque, and a cruise controller (162) configured to control a speed of the vehicle (100);wherein the method comprises (200) when the vehicle (100) is in motion with the cruisecontroller (162) activated and when an uphill section (510) of a road in front of thevehicle (100) is detected: reducing (210) the speed of the vehicle (100) from a first speed v1 to a secondspeed v2 prior to reaching the uphill section (510) by reducing the initial torque tarmgenerated by the internal combustion engine (101) to a first torque t1; and thereafter increasing (220) the speed of the vehicle (100) from the second speed vz to a thirdspeed vs by increasing the torque generated by the internal combustion engine (101)to a second torque t2, wherein the second torque tz is higher than the initial torque tarm.

2. Method (200) according to claim 1, wherein the second torque t2 is generated by theinternal combustion engine (101 ) when the vehicle (100) reaches a position of the uphillsection (510) where a driving resistance for the vehicle (100) equals or exceeds a maximum torque that may be generated by the internal combustion engine (101).

3. Method (200) according to claim 2, wherein the second torque t2 is the maximum torque that may be generated by the internal combustion engine (101).

4. Method (200) according to any one of the preceding claims, further comprising determining (202) the second speed vz prior to the reducing (210) the speed of the vehicle (100) based on at least one of: the first speed v1, the second torque tz, a weight of the vehicle (100), a current gear ratio of a transmission of the vehicle (100),a distance to the uphill section (510), an inclination of the uphill section (510), and an inclination of a road section in front of the vehicle before the uphill section(510).

5. Method (200) according to claim 4, further comprising when the vehicle (100) istrailing a leading vehicle (180) determining (202) the second speed v2 further based on at least one of:a distance to the leading vehicle (180), and a speed of the leading vehicle (180).

6. Method (200) according to any one of the preceding claims, further comprising determining (204) a first position d1 where the reducing (210) of the speed iscommenced based on the second speed vz.

7. Method (200) according to claim 6, wherein the reducing (210) of the speed is commenced at the first position d1.

8. Method (200) according to any one of the preceding claims, further comprising determining (212) a second position d2 where the increasing (220) of the speedis commenced based on the second speed vz.

9. Method (200) according to claim 8, wherein the increasing (210) of the speed is commenced at the second position d2.

10. Method (200) according to any one of the preceding claims, wherein the uphillsection (510) has at least one of: a first inclination,a length, and a driving resistance equal or exceeding a maximum torque that may be generated by the internal combustion engine (101).

11. Method (200) according to any one of the preceding claims, wherein the uphillsection (510) has an expected reduction of the speed of the vehicle (100) exceeding a speed reduction threshold value Avm.

12. Method (200) according to any one of the preceding claims, wherein the vehicle(100) further comprises a turbocharger (119) configured to increase a power output of the internal combustion engine (101), and further configured to build-up a pressure such that an additional torque tq is generated by the combustion engine (101 ).

13. A control arrangement (160) for controlling a vehicle (100), the vehicle (100) comprising:an internal combustion engine (101) configured to generate a torque, anda cruise controller (162) configured to control a speed of the vehicle (100); wherein the control arrangement (160) is configured to when the vehicle (100) is inmotion with the cruise controller (162) activated and when an uphill section (510) of aroad in front of the vehicle (100) is detected: reduce (210) the speed of the vehicle (100) from a first speed v1 to a second speedvz prior to reaching the uphill section (510) by reducing the torque generated by theinternal combustion engine (101) to a first torque t1; and thereafter increase (220) the speed of the vehicle (100) from the second speed vz to a thirdspeed vs by increasing the torque generated by the internal combustion engine (101) to a second torque t2, wherein the second torque tz is higher than the first torque t1.

14. A vehicle (100) comprising a control arrangement (160) according to claim 13.

15. Computer program comprising instructions which, when the program is executedby a computer, cause the computer to carry out the method (200) according to any oneof the claims1-12.

16. Computer-readable medium comprising instructions which, when executed by acomputer, cause the computer to carry out the method (200) according to any one ofthe claims1-12.