Patent Description:
Modern vehicles are commonly provided with control systems arranged for controlling different functions of the vehicle. Examples of such control systems include gearbox control systems, for example automatic or semi-automatic gearbox control systems arranged for shifting a current used gear and/or are equipped with gear shifting indication systems arranged for indicating to a driver when it is suitable to shift the current used gear and to which gear the shift should be.

In vehicles equipped with such gearbox control systems, e.g. with automated manual transmission gearbox, gear selection, gear shift and clutch operations are performed automatically instead of manually by the driver of the vehicle.

Such systems thus provide a method for controlling the gearbox, which may be based on an algorithm deciding when and how it is suitable to shift the used gear. The method for controlling the gearbox should generally provide gear shifts that result in a lowest possible fuel consumption. The method for controlling the gearbox may also take other parameters into consideration, such as e.g. a requested vehicle speed and a requested engine power/torque. Further, one or more dynamic parameters may also be taken into consideration, such as a current and an upcoming driving situation for the vehicle, e.g. in connection with varying road slopes/gradients. Other examples of vehicle control systems include systems for controlling different brake systems onboard the vehicle. Such a braking control, based on commands initiated by the vehicle's driver and/or other control units, may be performed by the control system sending control signals to suitable system modules to demand desired braking force from desired brake systems.

<CIT> discloses a shifting control method that improves driving stability by reducing roll-back of a vehicle during the process of shifting on an uphill slope. The shifting control method for a hybrid vehicle includes: determining a degree of roll-back of the vehicle on the basis of a change in the number of revolutions of a transmission input shaft, when power-off down-shifting into a lowest gear is requested; decreasing a disengaging clutch torque, increasing an engaging clutch torque, and increasing a motor torque so that the motor torque follows a desired motor torque, when the degree of roll-back is equal to or greater than a set value; synchronizing a motor speed with an engaging input shaft speed by decreasing the motor torque, when the disengaging clutch torque is equal to or less than a set torque; and finishing the shifting by increasing the motor torque when the synchronization is finished.

It is an objective of the invention to provide a method and a control arrangement for mitigating or solving drawbacks of conventional solutions. In particular, an objective of the invention is to provide a solution for downshifting gears in an uphill slope.

According to an aspect of the invention, these and further objectives are achieved through a method performed by a control arrangement of a vehicle;.

Applying the method according to the invention makes it possible for a vehicle traveling in an uphill slope to predict whether a downshift may be implemented without the risk of the vehicle speed becoming too low. Too low vehicle speed might lead to unwanted vehicle behaviour like engine stalling and/or the vehicle rolling backwards. For example, in cases when the vehicle starts rolling backwards it might, due to a steep inclination and/or heavy weight of the vehicle, become difficult to brake the vehicle or take a relatively long time to brake the vehicle to a full stop, which may lead to potentially uncontrollable vehicle movement and dangerous traffic situation. By performing one or several simulations of future speed profiles and considering possible downshift scenarios, the vehicle obtains very good control over the vehicle's speed during and after a downshift. Such simulations may be based on different type of information and be performed in a large number of ways which will be explained further. Based on these simulations, it may be determined if a downshift can be performed safely. In case it is determined that a downshift cannot be performed safely due to the speed becoming too low, the vehicle may be controlled by activating the vehicle brakes to make the vehicle decelerate and by inserting a start gear instead to the intended downshift gear. In this way, the risk of uncontrollable vehicle movement is reduced.

According to an embodiment of the invention, the opening of the clutch is performed according to one in the group of:.

Before downshifting gear to a start gear Gstart it is desirable to reduce the engine speed in a fast and controlled way to avoid jerky vehicle movement or vehicle engine stalling. Thus, the vehicle is here controlled in a reliable way such that the risk of engine stalling due to too low speed or jerky vehicle movement due to too high torque is mitigated.

According to an embodiment of the invention, the at least one brake is activated according to one in the group of:.

Hereby, by activating the at least one brake when the vehicle speed is equal to zero, or within a predetermined speed threshold level, the braking of the vehicle is done in a reliable and efficient way such that the risk of the vehicle rolling backwards is mitigated.

According to an embodiment of the invention, the activating of the at least one brake includes braking the vehicle to a standstill.

Hereby, the risk of the vehicle rollback is avoided, and the gear of the vehicle's gearbox can be shifted to the start gear, which may be done when the vehicle is at standstill.

According to an embodiment of the invention, the start gear Gstart is one in the group of:.

Hereby, the vehicle is controlled such that the automated manual transmission gearbox is shifted to a start gear, the start gear being the gear with the highest transition. Depending on the gearbox, the start gear can either be a lowest gear G<NUM> or a crawler gear Gcrawl. Thus, a maximum power is provided by the vehicle engine.

According to an embodiment of the invention, the closing of the clutch and the deactivating of the at least one brake are at least partly synchronized, and result in a drive-off for the vehicle.

By at least partly synchronizing the closing of the clutch and the deactivating of the at least one brake the risk of the vehicle drive-off with activated brake is mitigated. Thus, the wear on the gearbox and on other components in the vehicle is reduced.

According to an embodiment of the invention, the simulating of the at least one speed profile Vsim-<NUM>, Vsim-<NUM>,. , Vsim-n includes;.

By comparing the driving resistance force Fres acting to retard/decelerate the vehicle with at least one simulated traction force Ftrac-<NUM>, Ftrac-<NUM>,. Ftrac-n after the gearshift acting to accelerate/propel the vehicle, the total force acting on the vehicle and thus a speed of the vehicle may be determined. Based on the determined speed of the vehicle it may be determined if a downshift can be performed.

According to an embodiment of the invention, the simulating of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n is based on at least one in the group of:.

Hereby, the simulation may be based on one or more of a large number of different information/parameters. Thus, an accurate speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n may be simulated in any situation, providing a reliable information of vehicle behaviour after a downshift.

According to an embodiment of the invention, the simulating of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n is based on information associated with the uphill slope.

Hereby, more accurate simulations may be provided.

According to an embodiment of the invention, the information associated with the uphill slope includes one or more of:.

Hereby, the simulation may be based on information associated with the uphill slope, which may include various types of information, such as topology of the uphill slope, as will be explained further. Thus, a simulation method is provided where the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n can be more accurately simulated for any topographical aspect.

According to an embodiment of the invention, before the simulating of the at least one speed profile vsim-<NUM>, vsim-<NUM>,.

Thus, it is here determined that the engine power is not high enough to propel the vehicle in the uphill slope when the initial gear Ginit is used and hence engine stalling and/or backwards rolling of the vehicle can be mitigated or avoided.

According to an aspect of the invention, a control arrangement for a vehicle is provided. The vehicle includes:.

the control arrangement being configured for:.

According to an aspect of the invention, a vehicle including the herein disclosed control arrangement is provided.

It will be appreciated that all the embodiments described for the method aspects of the invention are applicable also to the control arrangement aspect of the invention. Thus, all the embodiments described for the method aspect 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 advantages corresponding to the advantages mentioned above for the method and its embodiments.

According to an aspect of the invention, a computer program and a computer-readable medium are provided. The computer program and the computer-readable medium comprise instructions which, when executed by a computer, cause the computer to carry out the method disclosed herein.

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:.

Providing a method for automatic control of the gear shifting such that the vehicle performs in accordance with the requests of the driver and/or cruise control systems with lowest possible fuel consumption and acceptable exhaust emissions may be challenging. This is e.g. due to the fact that some of the parameters that should be taken into consideration when controlling the gear shifting counteract each other.

Currently, engine efficiency and the requests of the driver and/or cruise control systems are often used as basis for automatic gear shifting control decisions. However, to base the gear shifting control on the engine efficiency and on requests of the driver and/or cruise control systems may, in some specific situations, lead to non-optimal gear shifting decisions, e.g. when gear shifting is done in an uphill slope.

When a vehicle travelling in an uphill slope is being decelerated due to the engine not being able to keep the speed at the current gear, a gear downshift may become necessary to increase the engine power and re-accelerate the vehicle by increasing the traction force acting on the vehicle in the driving direction obtained from the engine of the vehicle via the driving wheels. However, since a gear shift takes time to accomplish, it will lead to a further decrease in vehicle speed. In the case when the time for performing the gear shifting is not sufficient due to the initial speed of the vehicle and the inclination of the slope, the vehicle may start rolling backwards leading to potentially dangerous situations.

<FIG> schematically illustrate a forward driving traction force obtained from an engine of a vehicle via driving wheels and vehicle speed during a successful gear downshift from an initial gear Ginit to a lower gear when the vehicle is travelling in an uphill slope. <FIG> shows a simplified illustration of the forward driving traction acting on the vehicle as a function of time during a gear downshift while <FIG> shows a simplified illustration of the corresponding speed of the vehicle as a function of time during the gear downshift.

During a time period between a time instance t1 and a time instance t2, an initial traction force Ftract_ini is acting on the vehicle, as illustrated in <FIG>, when the vehicle is driving with an initial gear Ginit. The vehicle is also exposed to a driving resistance force Fres acting to retard/decelerate the vehicle which, during this time period, is larger than the propulsive traction force Ftract_ini acting on the vehicle. The vehicle is thus being decelerated as shown in <FIG>. Since the vehicle cannot maintain a required speed vreq, a gear downshift is necessary to increase the engine power, such that the propulsive traction force Ftract is increased above the value of the driving resistance force Fres, where the traction force equals the driving resistance force Fres, and the vehicle can be re-accelerated.

At the time instance t2, a gear downshift from the initial gear Ginit to a lower gear is initiated. During the time period tramp_down between the time instance t2 and a time instance t3, the torque provided from the vehicle's engine to the at least one drive wheel of the vehicle is ramped down before opening a vehicle clutch to avoid jerky vehicle movement. Thus, the traction force Ftract acting on the vehicle is reduced from the initial traction force level Ftract_ini to a lower level Ftract_idl as shown in <FIG>. The level of Ftract_idl may e.g. correspond to an idling engine speed for the initial gear Ginit. During this time period, the vehicle speed may continue to decrease, as shown in <FIG>.

Between the time instance t3 and a time instance t4, the downshift is conducted by opening/disengaging the clutch, shifting the initial gear Ginit to a neutral gear, shifting the neutral gear to a lower gear and finally closing/engaging the clutch. During this time period tsync no torque is obtained from the engine and thus no traction force Ftract is acting on the vehicle. During time period tsync, when the clutch is disengaged, the vehicle decelerates further as shown in <FIG> due to the forces acting on the vehicle in the uphill slope.

During the time period tramp_up between the time instance t4 and a time instance t5, the driver requests an engine torque by use of the accelerator pedal after which the torque provided by the engine is increased leading to an increased traction force acting on the vehicle to finally, at the time instance t5, reach a traction force level Ftract_req corresponding to the driver requested engine torque, as shown in <FIG>. During this time period tramp_up when the traction force increases above the value of the driving resistance force Fres, the vehicle may start to accelerate as shown in <FIG>.

At the time instance t5 the traction force emitted by a vehicle's engine via the driving wheels corresponds to a requested engine torque and thus the downshift has been completed.

At some time instance during the downshift period tshift or after the downshift has been completed, the vehicle reaches a lowest speed vmin which in the example illustrated in <FIG> occurs between the time instances t4 and t5, when the traction force reaches a level larger than Fres. However, the speed can reach its minimum at any time instance during or after the downshift period tshift. If the lowest speed during or after the downshift vmin reaches <NUM>/h or below, the vehicle, when being in the uphill slope, will move backwards, which might lead to potentially dangerous situations.

<FIG> schematically shows an exemplary heavy vehicle <NUM>, such as a truck carrying a heavy cargo/load, which will be used to explain the herein presented embodiments of the invention. However, the embodiments are not limited to use in vehicles such as the ones shown in <FIG>, but may be used in any suitable vehicle, such as lighter vehicles, e.g. smaller trucks and cars.

The vehicle <NUM> in <FIG>, comprises a first of drive wheels <NUM>, <NUM> and at least one second pair of wheels <NUM>, <NUM>. The vehicle <NUM> furthermore comprises a driveline/drivetrain/powertrain <NUM> configured to transfer a torque between at least one power source <NUM>, such as e.g. an engine, and the drive wheels <NUM>, <NUM>. The at least one power source <NUM> may include a combustion engine, at least one electrical machine, or a combination of these, implementing a so-called hybrid drive. The at least one power source <NUM> may, when being a combustion engine, be provided with fuel from a fuel tank <NUM> coupled to the at least one power source. The power source <NUM> may also be provided with electrical energy by at least one battery <NUM> coupled to the at least one power source.

The at least one power source <NUM> is for example in a customary fashion, via an output shaft <NUM> of the engine <NUM>, connected to a clutch <NUM>, and via the clutch also to a gearbox <NUM> which may be an automated manual transmission gearbox. The torque provided by the engine <NUM> is provided to an input shaft <NUM> of the gearbox <NUM>. A propeller shaft <NUM>, connected to an output shaft of the gearbox <NUM>, drives the drive wheels <NUM>, <NUM> via a final gear <NUM>, such as e.g. a customary differential, and drive shafts <NUM>, <NUM> connected with the final gear <NUM>. Also, one or more electrical machine may be arranged essentially anywhere along the driveline <NUM>, as long as torque is provided to one or more of the wheels <NUM>, <NUM>, <NUM>, <NUM>, e.g. adjacent to one or more of the wheels <NUM>, <NUM>, <NUM>, <NUM>, as is understood by a skilled person.

The vehicle <NUM> also may include at least one braking arrangement <NUM>, <NUM>, <NUM>, <NUM>, for example one braking arrangement <NUM>, <NUM>, <NUM>, <NUM> arranged at each one of the wheels of the vehicle <NUM>. The at least one braking arrangement <NUM>, <NUM>, <NUM>, <NUM> may be included in at least one braking system <NUM>. Braking of the vehicle <NUM>, which may result in a retardation of the vehicle <NUM>, by use of the at least one braking arrangement <NUM>, <NUM>, <NUM>, <NUM> may be achieved in a number of well-known ways. The at least one braking system <NUM> may also include one or more additional braking devices <NUM>, for example one or more additional braking devices acting on the driveline <NUM>, such as a retarder, and/or an exhaust brake device. The at least one braking system <NUM>, including the at least one braking arrangement <NUM>, <NUM>, <NUM>, <NUM> and/or the at least one additional braking device <NUM> may be controlled by at least one control arrangement <NUM>, which is described more in detail below.

The control arrangement <NUM> may be implemented on single control unit/device or physical entity or distributed in two or more separate control units/devices or physical entities. For example, the control arrangement <NUM>, may be distributed on several control units configured to control different parts of the vehicle <NUM>. The control arrangement <NUM> may e.g. include a simulation unit <NUM>, a determination unit <NUM>, an opening unit <NUM>, an activation unit <NUM>, shifting unit <NUM>, a closing unit <NUM> and a deactivation unit <NUM> arranged for performing the method steps of the disclosed invention as is explained further on. The control arrangement <NUM> and/or another control unit/device may further be configured for controlling one or more of the at least one power source <NUM>, the clutch <NUM>, the gearbox <NUM>, and/or any other units/devices/entities of the vehicle. However, in <FIG>, only the units/devices/entities of the vehicle <NUM> useful for understanding the invention are illustrated.

The vehicle <NUM> may further include one or more sensors <NUM>, e.g. at least one camera and/or at least one pressure sensor, located at suitable positions within the vehicle <NUM>.

Further, the vehicle <NUM> may comprise a positioning system/unit <NUM>. The positioning unit <NUM> may be based on a satellite navigation system such as the Navigation Signal Timing and Ranging (Navstar), Global Positioning System (GPS), Differential GPS (DGPS), Galileo, GLONASS, or the like. Thus, the positioning unit <NUM> may comprise a GPS receiver.

The vehicle <NUM> may also include at least one input device <NUM> arranged for receiving an input from the driver, as is described more in detail below. The at least one input device may include at least one button, at least one knob, at least one lever, at least one touch screen, or any other suitable input device.

The vehicle <NUM> may further include at least one communication device <NUM> arranged for communication with at least one entity <NUM> external to the vehicle <NUM>, such as e.g. an infrastructure entity, a communication entity of another vehicle and/or a positioning information entity.

According to an embodiment of the invention, the at least one communication device <NUM> may be essentially any device transferring information to and/or from the vehicle <NUM>, and the at least one entity <NUM> external to the vehicle <NUM> may be essentially any external entity communicating with the vehicle, i.e. with the at least one communication device <NUM>, for the transfer of the information to and/or from the vehicle. Thus, the at least one external entity <NUM> may e.g. be associated with, such as being included in, an infrastructure entity and/or another vehicle. Correspondingly, as mentioned above, the at least one communication device <NUM> may be a vehicle-to-vehicle (V2V) communication device, a vehicle-to-infrastructure (V2I) communication device, and/or a vehicle-to-everything (V2X) communication device, such that communication between the vehicle <NUM> and the at least one external entity <NUM> is achieved/provided.

<FIG> shows a flow chart of an embodiment of a method <NUM> performed by a control arrangement <NUM> of a vehicle <NUM>, e.g. such as the vehicle disclosed in <FIG>, for driving in an uphill slope <NUM>, i.e. in an ascending road section.

As previously mentioned with reference to <FIG>, the vehicle <NUM> includes a driveline <NUM>, arranged for providing a torque Tq_wheel to at least one drive wheel <NUM>, <NUM>, the driveline <NUM> including at least one engine <NUM>, a clutch <NUM> and at least one automated manual transmission gearbox <NUM>. Moreover, the vehicle <NUM> includes at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> arranged for braking the vehicle <NUM>. The at least one brake may comprise one or more of at least one service brake <NUM>, <NUM>, <NUM>, <NUM>, at least one auxiliary brake <NUM>, at least one parking brake <NUM>, <NUM>, <NUM>, <NUM>.

The method <NUM> may be executed when the vehicle <NUM> is travelling in an uphill slope <NUM> using an initial gear Ginit of the at least one automated manual transmission gearbox <NUM> and an initial speed of vact-init. The initial gear Ginit can be any gear of the automated manual transmission gearbox <NUM>.

In step <NUM>, at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n is simulated, for example with the use of the simulation unit <NUM> described above. The at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n being for a downshift to, and a usage of, at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n of the at least one automated manual transmission gearbox <NUM> being lower than the initial gear Ginit in the uphill slope <NUM>.

In step <NUM>, it is determined that a minimum speed vmin_1, vmin_2,. Vmin_n, i.e. the lowest speed value, of each one of the at least one simulated speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n has a value indicating that the actual speed vact for the vehicle <NUM> will be less than or equal to zero vsim-<NUM>≤<NUM>, vsim-<NUM>≤<NUM>,. , vsim-n≤<NUM> in the uphill slope <NUM>.

In step <NUM>, the clutch <NUM> is opened, before the actual speed of the vehicle vact is reduced to a value less than zero km/h.

In step <NUM>, the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is activated.

In step <NUM>, the at least one automated manual transmission gearbox <NUM> is shifted to a start gear Gstart.

In step <NUM>, the clutch <NUM> is closed.

In step <NUM>, the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is deactivated completing the gearshift.

By simulating the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n of the vehicle <NUM> in step <NUM> a speed profile, i.e. speed variations, of the vehicle <NUM> during the downshift phase tshift may be determined when downshifting to at least one lower gear. By determining that each of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n will reach a minimum speed, less than or equal to zero, in step <NUM> it is determined that a downshift in the uphill slope <NUM> may lead to too low vehicle speed during or after the downshift phase tshift. However, if a downshift is not performed the engine <NUM> might lose power which might lead to engine stalling. On the other hand, a downshift may, due to the low actual speed of the vehicle <NUM>, lead to backward moving of the vehicle <NUM> due to the driving resistance force Fres acting to retard/decelerate the vehicle <NUM> in the uphill slope <NUM>. By controlling the vehicle <NUM> according to method of the invention, when determined that a downshift in uphill slope may lead to too low vehicle speed, according to steps <NUM>-<NUM>, a controlled and reliable downshift is achieved, avoiding unexpected and unwanted potentially dangerous vehicle behavior and leading to increased safety for the vehicle itself and its owner and persons and objects behind the vehicle.

In addition to the above described method steps <NUM> - <NUM>, the method <NUM> may in an embodiment, comprise a number of optional steps. <FIG> shows a flow chart of method <NUM> according to an embodiment of the invention.

It should be noted that the method steps illustrated in <FIG> and described herein do not necessarily have to be executed in the order illustrated in <FIG>. The steps may essentially be executed in any suitable order, as long as the physical requirements and the information needed to execute each method step is available when the step is executed.

In an optional step <NUM>, preceding the previously described step <NUM>, it is in an embodiment determined that an initial gear Ginit of the at least one automated manual transmission gearbox <NUM>, used by the vehicle <NUM> travelling in an uphill slope <NUM>, has a gear ratio such that the at least one engine <NUM> is unable to drive the vehicle <NUM> in the uphill slope <NUM> using the initial gear Ginit. Thus, it is here determined that the engine power is not high enough to propel the vehicle <NUM> in the uphill slope <NUM> when the initial gear Ginit is used.

In an optional step <NUM>, it is, in an embodiment, determined that a downshift to a lower gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n should be performed.

The determining <NUM> may, for example, be based on one or more threshold values. The determining <NUM> may, according to one example, be based on a speed threshold value vth, such that when the speed of the vehicle vact, at a maximum engine speed when the initial gear Ginit is used, drops below the speed threshold value vth, it is determined that a downshift to a lower gear should be performed. The determining may, according to another example, be based on a torque threshold value Tth, such that when the torque Tq_wheel provided to the at least one drive wheel <NUM>, <NUM> of the vehicle <NUM> at a maximum engine speed when the initial gear Ginit is used drops below the torque threshold value Tth, it is determined that a downshift to a lower gear should be performed. According to yet another example, the determining may be based on an engine speed threshold value ωth, such that when the maximum engine speed of the vehicle <NUM> when the initial gear Ginit is used drops below the engine speed threshold value ωth, it is determined that a downshift to a lower gear should be performed.

In step <NUM>, as previously described, at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n is simulated. The simulation may be, for example, performed by means of the previously described simulation unit <NUM>.

The simulation of the at least one speed profile may be here carried out when the vehicle <NUM> is travelling using an initial gear Ginit of the at least one automated manual transmission gearbox <NUM>. The simulation may be carried out for at least one downshift step i.e. for a downshift to, and a usage of, at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n of the at least one automated manual transmission gearbox <NUM> being lower than the initial gear Ginit. In a non-limiting example, a simulation may be carried out for all downshift steps i.e. for Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n where Ginit-n is the start gear Gstart. In another non-limiting example, in order to limit the load on the simulation unit <NUM>, the simulation may be carried out for downshift steps that are reasonably possible when the simulation is performed. In a non-limiting example, the reasonably possible downshift steps may be determined by a decision logic and be based e.g. on an engine working area of the vehicle <NUM>. The vehicle's working area corresponds to a possible engine speed range for each gear the vehicle <NUM> may be driven. The engine speed range is generally between an idling engine speed ωidl, e.g. <NUM> Rotations Per Minute (RPM) up to a maximum engine speed, e.g. <NUM> RPM. Thereby, when the vehicle <NUM> is driving at an actual speed , e.g. <NUM>/h, only a few gears of the gearbox are reasonably possible in order to keep the engine speed within its speed range. If any of the gear shift steps is outside the engine's speed range given the vehicle's traveling speed, the shift step is not possible and needs not to be considered during the simulation. Such decision logic may be e.g. implemented by means of the control arrangement <NUM> of the vehicle <NUM>. In a non-limiting example, speed profile simulations for the at least one of the possible downshift steps during and after a downshift may be carried out in the vehicle <NUM> with a predetermined frequency, such as for example several times per second.

Speed profile simulations may be performed in a large number of ways, that are all included in the scope of the invention. For example, the simulated speed profile, according to an exemplifying embodiment may be performed based on various types of information.

According to an embodiment, the simulating <NUM> of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n may include comparing driving resistance force Fres acting on the vehicle <NUM> in the uphill slope <NUM> with at least one simulated traction force Ftrac-<NUM>, Ftrac-<NUM>,. Ftrac-n resulting from the torque Tq_wheel provided to the at least one drive wheel <NUM>, <NUM> after the downshift for the at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n, respectively.

A non-limiting example of a driving situation of a vehicle <NUM> where an embodiment of the invention may be applied is schematically illustrated in <FIG>.

The vehicle <NUM> travels with a speed vact in an uphill slope <NUM> with an inclination α.

The vehicle <NUM>, is exposed to a resistance force Fres acting backwards i.e. acting to decelerate the vehicle and a forward traction force Ftract, i.e. acting to accelerate the vehicle or at least propel the vehicle at a constant speed. The forward traction force results from the torque Tq_wheel provided by the vehicle's engine to the at least one drive wheel <NUM>, <NUM> and depends on which gear is used, the final gear ratio and the radius of the at least one drive wheel <NUM>, <NUM>.

When the vehicle <NUM> travels up or down a slope, its weight produces a component called grading resistance Fg, which is always directed in the downhill direction. Moreover, the vehicle <NUM> travelling at a particular speed encounters other forces resisting its motion i.e. forces counteracting the vehicle's movement like air resistance Fair and other rolling forces Froll due to rolling resistance, engine and gearbox friction, etc. Thus, for the vehicle <NUM> travelling in the uphill slope <NUM> with a speed vact, the resistance force Fres acting backwards will comprise the grading resistance force Fg as well as the air resistance Fair and the rolling forces Froll.

For the vehicle <NUM> in <FIG>, an energy relationship may be set up for the driving situation. The backward and forward forces Fres and Ftract will affect the speed of the vehicle <NUM>. By comparing the traction force Ftrac and the resistance force Fres acting on the vehicle <NUM> a speed profile of the vehicle can be simulated. When the vehicle <NUM> is travelling at a constant speed the traction force Ftrac is equal to the resistance force Fres, Ftrac - Fres = <NUM>. When the traction force Ftrac is larger than the resistance force Fres, Ftrac - Fres > <NUM> the vehicle accelerates and in similar way, when the traction force Ftrac is smaller than the resistance force Fres, Ftrac - Fres < <NUM>, the vehicle decelerates.

The at least one traction force Ftrac-<NUM>, Ftrac-<NUM>,. Ftrac-n acting on the vehicle <NUM> which, as previously described, may be used for simulating of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , Vsim-n, may be for example determined based on the gear ratio for the applied gear and for the final gear and on the radius of the at least one drive wheel <NUM>, <NUM> using the principles of the dynamics of the vehicle. In similar way, the weight of the vehicle, the air resistance acting on the vehicle <NUM>, the rolling resistance acting on the vehicle <NUM> and the inclination of the uphill slope may be used to determine the driving resistance force Fres acting on the vehicle <NUM> in the uphill slope. The increase and decrease of the vehicle speed may be based on the at least one timing parameter related to the downshift to at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n and the traction force resulting from the torque Tq_wheel provided to the at least one drive wheel <NUM>, <NUM> during tramp_up and tramp_down.

In an embodiment, the simulation <NUM> may be based on at least one vehicle related parameter such as the initial actual speed of the vehicle <NUM> before the downshift, the initial engine speed of the at least one engine <NUM> before the downshift, the vehicle weight, the air resistance acting on the vehicle <NUM>, a rolling resistance acting on the vehicle <NUM>, the radius of the at least one drive wheel and/or at least one parameter related to the uphill slope <NUM>, such as the inclination angle of the uphill slope <NUM>.

Furthermore, the simulation may be based on at least one engine characteristics such as a gear ratio in the gearbox and/or the driveline such as the gear ratio for the initial gear Ginit, the gear ratio for each one of the at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n being lower than the initial gear Ginit, and the gear ratio for the final gear, maximum and/or minimum engine torque.

Moreover, the simulation may be based on at least one timing parameter related to the downshift to at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n, such as the time period needed to complete a downshift from the initial gear Ginit to the gear ratio for each one of the at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n being lower than the initial gear Ginit, a time period tramp_down for a decrease of a torque Tq_wheel being provided to the at least one drive wheel <NUM>, <NUM> in connection with the downshift, a time period tramp_up for an increase of a torque Tq_wheel being provided to the at least one drive wheel <NUM>, <NUM> in connection with the downshift and a synchronization time period tsync in connection with the downshift and the traction force resulting from the torque Tq_wheel provided to the at least one drive wheel <NUM>, <NUM> during tramp_up and tramp_down.

The above-mentioned parameters relevant for simulating <NUM> the at least one future speed profile of the vehicle <NUM> may be provided onboard the vehicle <NUM>, e.g. by one or more onboard sensors <NUM> and/or may be provided to the vehicle <NUM> by another vehicle, i.e. by V2V communication, and/or by an infrastructure entity, i.e. by V2I communication.

In an embodiment, the simulating <NUM> of the at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n is based on information associated with the uphill slope <NUM>. The information associated may for example be related to a road section ahead of the vehicle.

The information associated with the uphill slope <NUM>, may in an embodiment include information associated with a position of the vehicle <NUM>, map associated information, information associated with one or more features of the uphill slope <NUM> and/or information associated with an inclination α of the uphill slope.

Generally, the information associated with the uphill slope <NUM> may be determined based on information from one or more sensors <NUM> which may be included in the vehicle <NUM> e.g. one or more camera, one or more radar equipment and/or a positioning system/unit, such as GPS. Moreover, the information associated with the uphill slope <NUM> may be provided by another vehicle, i.e. by V2V communication, and/or by an infrastructure entity, i.e. by V2I communication, be obtained based on radar information, on camera information, on positioning information stored previously in the vehicle <NUM> and, on information obtained from traffic systems related to the road section.

For example, information associated with a position of the vehicle <NUM> may be provided by a positioning system in the vehicle, such as by GPS. Map associated information e. g, from digital maps may, for example include topology information of an electronic map. Typically, positioning information may be used for positioning the vehicle <NUM> on the correct location of a digital map, whereby information associated with one or more features of the uphill slope <NUM>, may easily be determined/provided based on the map. The one or more features of the uphill slope <NUM> may comprise, among others, the inclination α and/or a curvature for the uphill slope <NUM>. If map data is not available, the inclination α of the uphill slope <NUM>, may be obtained by way of estimating the inclination experienced by the vehicle <NUM> at the time of simulation, e.g. based on an engine torque in the vehicle, on an acceleration of the vehicle, on an accelerometer, on GPS information, on radar information, on camera information, on information from another vehicle, on positioning-related and road gradient information stored previously in the vehicle, and/or on information obtained from traffic systems related to said road section. In systems where information exchange between vehicles is used, the inclination α estimated by a vehicle <NUM> may also be provided to other vehicles, either directly or via an intermediate unit, such as a database or similar.

Simulations of the at least one speed profile according to an example may be carried out in the vehicle <NUM> with a predetermined frequency.

In step <NUM>, it is, as previously described, determined that a minimum speed vmin_1, vmin_2,. vmin_n, i.e. the lowest speed value, of each one of the at least one simulated speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n has a value indicating that the actual speed vact for the vehicle <NUM> will be less than or equal to zero vsim-<NUM>≤<NUM>, vsim-<NUM>≤<NUM>,. , vsim-n≤<NUM> in the uphill slope <NUM>.

Hence, it is here determined that all of the at least one simulated speed profiles will reach a minimal speed with a value less than or equal to zero which indicates that none of the simulated gear downshifts can be performed since the actual speed of the vehicle vact will become too low at some point during or after the downshift phase tshift which may lead to the engine <NUM> stalling, i.e. stop running, and/or the vehicle <NUM> rolling backwards.

The determination <NUM> may be executed with the use of the determination unit <NUM> described above.

In step <NUM>, as described before, the clutch <NUM> is opened, before the actual speed of the vehicle vact is reduced to a value less than zero km/h. When the clutch <NUM> is opened, or disengaged, no torque Tq_wheel is transferred from the engine <NUM> to the automated manual transmission gearbox <NUM> and by extension to the at least one drive wheel <NUM>, <NUM>. In this uncoupled state, i.e. the open driveline state, it is possible to change gears and/or to stop the vehicle <NUM> without stopping the engine <NUM>.

In an optional step <NUM>, the clutch <NUM> may in an embodiment be opened when the actual speed vact of the vehicle <NUM> is between zero km/h and an idling vehicle speed Vidl.

Before opening the clutch, it is desirable to reduce the engine speed in a fast and controlled way to avoid jerky vehicle movement or vehicle engine stalling. In a non-limiting example, the engine speed may be reduced, reducing the vehicle speed, to a level corresponding to or below an idling vehicle speed vidl i.e. corresponding to an idling engine speed ωidl for the gear ratio of the applied gear. However, opening the clutch at a too low speed, i.e. when the vehicle <NUM> has come to a stop, may result in vehicle engine stalling, i.e. stop moving.

In an embodiment, in an optional step <NUM>, the speed of the vehicle <NUM> may be reduced by reducing the torque Tq_wheel being provided to the at least one drive wheel <NUM>, <NUM> before opening the clutch <NUM>.

In step <NUM>, as previously described, the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is activated. By applying one or more of at least one service brake <NUM>-<NUM> and the at least one auxiliary brake <NUM>, the actual speed vact of the vehicle <NUM> is controlled to be <NUM> or close to <NUM>.

In an embodiment, the activating of the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be done when the actual speed vact of the vehicle <NUM> is equal to zero km/h to reduce the risk of the vehicle rolling backwards.

However, it might be difficult to identify the exact moment when the vehicle speed is equal to zero km/h, especially at very low speed. Therefore, in an embodiment the activating of the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be done when the actual speed vact of the vehicle is smaller than a speed threshold vact_th.

Generally, the speed threshold value used in the invention, that is to say the maximum actual speed vact at which the vehicle is to be braked by activating the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, may be determined in different ways. For example, it may be related to the actual speed vact of the vehicle at the idling engine speed ωidl for the initial gear Ginit. A person skilled in the art will obviously realize that vehicle speed and the speed threshold value, which are specified in this disclosure, have equivalents and may be translated into engine speed and engine speed threshold or torque and torque threshold value.

In step <NUM>, the at least one automated manual transmission gearbox <NUM> is, as previously described, shifted to a start gear Gstart to initiate a controlled gearshift.

A vehicle's gearbox may be shifted to a start gear Gstart when the vehicle is at a standstill or is moving with a speed close to <NUM>. Thus, in an embodiment, the activating of the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, performed in step <NUM>, includes braking the vehicle to a standstill.

The start gear Gstart may, according to an embodiment, be a lowest gear G<NUM> of the at least one automated manual transmission gearbox <NUM>.

A lowest gear of an automated manual transmission gearbox <NUM> without crawler gears may be gear number one G<NUM>. The lowest gear of an automated transmission gearbox <NUM> with one or more crawler gears may be the first crawler gear Gcrawl. Thus, according to an embodiment, the start gear Gstart may be a crawler gear Gcrawl.

In step <NUM>, the clutch <NUM> is, as previously described, closed. In this coupled state, i.e. the closed driveline state, the clutch <NUM> acts as coupling to transmit power to the automated manual transmission gearbox <NUM>. When the clutch <NUM> is closed, or engaged, the engine's <NUM> torque Tq_wheel , requested by the driver of the vehicle <NUM>, is again transferred to the at least one of the drive wheels <NUM>, <NUM>. The driver of the vehicle <NUM> requests an engine torque by use of an accelerator pedal which may be pressed down during the whole gearshift.

As previously described, in step <NUM>, the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> is deactivated. Hereby, the gearshift is completed, the vehicle <NUM> is in start gear and the risk of stalling and potentially rolling backwards has been mitigated.

In an embodiment, the closing <NUM> of the clutch <NUM> and the deactivating <NUM> of the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be at least partly synchronized, and may result in a drive-off for the vehicle <NUM>.

When the clutch <NUM> is closing, for example in connection with a gear change of the gear box, the torque provided by the engine, i.e. the engine torque Tq, will be provided to the driveline, including the gearbox. The engine and the clutch should preferably be synchronized, such that an increased engine torque Tq is provided to the clutch <NUM> when it is closing and not before that. Correspondingly, when the clutch <NUM> is opened, the engine and the clutch <NUM> should preferably be synchronized, such that a reduced engine torque Tq is provided to the clutch <NUM> when it is opening, and not before that.

According to an aspect of the invention, a control arrangement <NUM> of the vehicle <NUM> is provided.

The control arrangement <NUM> includes means, for example the simulation unit <NUM>, arranged for simulating <NUM>, when the vehicle <NUM> is travelling in an uphill slope <NUM> using an initial gear Ginit of the at least one automated manual transmission gearbox <NUM>, at least one speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n for a downshift to, and a usage of, at least one gear Ginit-<NUM>, Ginit-<NUM>,. , Ginit-n of the at least one automated manual transmission gearbox <NUM> being lower than the initial gear Ginit in the uphill slope <NUM>.

The control arrangement <NUM> further includes means, for example the determining unit <NUM>, arranged for determining <NUM> that a minimal speed vmin_1, vmin_2,. vmin_n of each one of the at least one simulated speed profile vsim-<NUM>, vsim-<NUM>,. , vsim-n has a value indicating that the actual speed vact of the vehicle <NUM> will be less than or equal to zero; vsim-<NUM>≤<NUM>; vsim-<NUM>≤<NUM>,. , vsim-n≤<NUM>; in the uphill slope <NUM>.

The control arrangement <NUM> further includes means, for example the opening unit <NUM>, arranged for opening <NUM> the clutch <NUM> before the actual speed vact of the vehicle <NUM> is reduced to a value less than zero; vact<<NUM>.

The control arrangement <NUM> further includes means, for example the activating unit <NUM>, arranged for activating <NUM> the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The control arrangement <NUM> further includes means, for example the shifting unit <NUM>, arranged for shifting <NUM> the at least one automated manual transmission gearbox <NUM> to a start gear Gstart.

The control arrangement <NUM> further includes means, for example the closing unit <NUM>, arranged for closing <NUM> the clutch <NUM>.

The control arrangement <NUM> further includes means, for example the deactivating unit <NUM>, arranged for deactivating <NUM> the at least one brake <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The control arrangement <NUM>, e.g. a device or a control device, according to the invention may be arranged for performing all of the above, in the claims, and in the herein described embodiments method steps. The control arrangement <NUM> is hereby provided with the above described advantages for each respective embodiment.

The present invention is also related to a vehicle <NUM> including the control arrangement <NUM>.

<FIG> shows in schematic representation a control arrangement <NUM>/<NUM>, which may correspond to or may include one or more of the above-mentioned control units <NUM> - <NUM> i.e. the control units performing the method steps of the disclosed invention. The control arrangement <NUM>/<NUM> comprises a computing/processing unit <NUM>, which can comprise essentially any suitable type of processor or microcomputer, for example a circuit for digital signal processing (Digital Signal Processor, DSP), or a circuit having a predetermined specific function (Application Specific Integrated Circuit, ASIC). The computing unit <NUM> is connected to a memory unit <NUM> arranged in the control arrangement <NUM>/<NUM>, which memory unit provides the computing/processing unit <NUM> with, for example, the stored program code and/or the stored data which the computing/processing unit <NUM> requires to be able to perform computations. The computing unit <NUM> is also arranged to store partial or final results of computations in the memory unit <NUM>.

In addition, the control arrangement <NUM>/<NUM> is provided with devices <NUM>, <NUM>, <NUM>, <NUM> for receiving and transmitting input and output signals. These input and output signals can contain waveforms, impulses, or other attributes which, by the devices <NUM>, <NUM> 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 <NUM>. These signals are then made available to the computing unit <NUM>. The devices <NUM>, <NUM> for the transmission of output signals are arranged to convert signals received from the computing/processing unit <NUM> in order to create output signals by, for example, modulating the signals, which can be transmitted to other parts of and/or systems in the vehicle.

Each of the connections to the devices for receiving and transmitting input and output signals 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 Transport bus), or some other bus configuration; or by a wireless connection. A person skilled in the art will appreciate that the above-stated computer can be constituted by the computing/processing unit <NUM> and that the above- stated memory can be constituted by the memory unit <NUM>.

Control systems in modern vehicles commonly comprise communication bus systems consisting of one or more communication buses for linking a number of electronic control 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 the responsibility 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 than are shown in <FIG> and <NUM>, which is well known to the person skilled in the art within this technical field.

In a shown embodiment, the invention may be implemented by the one or more above mentioned control units <NUM>-<NUM>. The invention can also, however, be implemented wholly or partially in one or more other control units already present in the vehicle, or in some control unit dedicated to the invention. The invention may be implemented wholly or partially in computer program code, which when executed by the computing/processing unit <NUM> (which may be one or more processers as described above, implemented in one or more physical entities) causes the control arrangement to perform the method as described herein.

Here and in this document, units are often described as being arranged for performing steps 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 <NUM>-<NUM> are in <FIG> illustrated as separate units. These units <NUM>-<NUM> may, however, be logically separated but physically implemented in the same unit or can be both logically and physically arranged together. These units <NUM>-<NUM> may for example 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 <NUM> 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 embodiments for downshifting gears in an uphill slope may also be implemented in a computer program, which, when it is executed in a computer, instructs the computer to execute the method. The computer program is usually constituted by a computer program product <NUM> stored on a non-transitory/non-volatile digital storage medium, in which the computer program is incorporated in the computer-readable medium of the computer program product. The computer-readable medium comprises a suitable memory, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc..

Claim 1:
Method (<NUM>) performed by a control arrangement (<NUM>) of a vehicle (<NUM>);
the vehicle including:
- a driveline (<NUM>) arranged for providing a torque Tq_wheel to at least one drive wheel (<NUM>, <NUM>), the driveline (<NUM>) including at least one engine (<NUM>), a clutch (<NUM>) and at least one automated manual transmission gearbox (<NUM>); and
- at least one brake (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) arranged for braking the vehicle (<NUM>);
the method is characterised by including:
- simulating (<NUM>), when the vehicle (<NUM>) is travelling in an uphill slope (<NUM>) using an initial gear Ginit of the at least one automated manual transmission gearbox (<NUM>), at least one speed profile vsim-<NUM>, vsim-<NUM>, ..., vsim-n for a downshift to, and a usage of, at least one gear Ginit-<NUM>, Ginit-<NUM>, ..., Ginit-n of the at least one automated manual transmission gearbox (<NUM>) being lower than the initial gear Ginit in the uphill slope (<NUM>);
- determining (<NUM>) that a minimal speed vmin_1, vmin_2, ... vmin_n of each one of the at least one simulated speed profile vsim-<NUM>, vsim-<NUM>, ..., vsim-n has a value indicating that the actual speed vact of the vehicle will be less than or equal to zero; vsim-<NUM>≤<NUM>; vsim-<NUM>≤<NUM>, ..., vsim-n≤<NUM>; in the uphill slope (<NUM>);
- opening (<NUM>) the clutch (<NUM>) before the actual speed vact of the vehicle is reduced to a value less than zero; vact<<NUM>;
- activating (<NUM>) the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
- shifting (<NUM>) the at least one automated manual transmission gearbox (<NUM>) to a start gear Gstart;
- closing (<NUM>) the clutch (<NUM>); and
- deactivating (<NUM>) the at least one brake (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>).