TECHNICAL FIELD

The present inventive concept relates generally to braking of a vehicle. In particular aspects, the inventive concept relates to a computer-implemented method of controlling a braking operation of a vehicle. The inventive concept can be applied in heavy-duty vehicles, such as trucks, buses, and construction equipment. Although the inventive concept may be described with respect to a particular vehicle, the disclosure is not restricted to any particular vehicle.

BACKGROUND

Electrified propulsion of passenger cars is becoming a conventional solution to reduce the environmental effect caused by vehicles. Heavy-duty vehicles, such as trucks, are also continuously developed to be able to provide electrified propulsion. The electrified propulsion system comprises one or more electric machines operable to generate a propulsion torque on one or more wheels of the vehicle.

Compared to a vehicle using an internal combustion engine (ICE) for its propulsion, an electrically propelled heavy-duty vehicle does not have the same ability to use its traction motors for braking as the ICE operated vehicle. In detail, when operating the vehicle in long downhill slopes, the battery may reach a maximum state of charge level, resulting in that further regeneration of electric power is not possible. A problem is thus that the service brakes will have to be utilized to a greater extent when reaching the maximum state of charge level, which may cause overheating of these brakes.

There is thus a desire to improve the braking operation of vehicles using an electric traction motor for its propulsion.

SUMMARY

It is thus a desire of the present inventive concept to at least partially overcome the above described deficiencies.

According to a first aspect, there is provided a computer-implemented method of controlling a braking operation of a vehicle, the vehicle comprising an electric traction motor configured to feed electric power, generated during braking, to a high voltage energy storage system, wherein the vehicle further comprises an auxiliary brake arrangement, a service brake arrangement, and processing circuitry operatively coupled to the high voltage energy storage system, the electric traction motor, the auxiliary brake arrangement, and the service brake arrangement, the method comprising determining, by the processing circuitry, road topography of an upcoming road path operable by the vehicle, determining, by the processing circuitry, a brake power demand level for operating the vehicle at a downhill slope of the upcoming road path at a desired speed, determining, by the processing circuitry, a desired charging level of the high voltage energy storage system before initiating operation at the downhill slope, comparing, by the processing circuitry, the brake power demand level with the desired charging level, and when the brake power demand level exceeds the desired charging level: controlling, by the processing circuitry, at least one of the auxiliary brake arrangement and the service brake arrangement in conjunction with the electric traction motor for operating the vehicle at the downhill slope with the desired speed.

The expression “processing circuitry” as used above should be understood to include any type of computing device, such as an ASIC, a micro-processor, etc. It should also be understood that the actual implementation of such a processing circuitry may be divided between more than a single device/circuit.

Further, the auxiliary brake arrangement should be construed as any arrangement of the vehicle that is operable to reduce the vehicle speed, except for the abovedefined electric traction motor and the service brake arrangement. Hence, the electric traction motor and the service brake arrangement do not form part of the auxiliary brake arrangement. According to examples, the auxiliary brake arrangement may be a brake resistor, which brake resistor can be configured to receive electric power generated by the electric traction motor during braking to dissipate electric energy. The auxiliary brake arrangement may also be, or comprise, an air compressor configured to pressurize a flow of air. Such air compressor is preferably operated by electric power generated by the electric traction motor during braking to thereby dissipate electric energy. According to another example, the auxiliary brake arrangement may be a retarder in which brake energy is dissipated into a liquid fluid, where the brake energy is subsequently dissipated to e.g. the ambient environment through a vehicle cooling system.

Still further, and in some examples, the desired charging level may be based on a power absorption capability of the high voltage energy storage system. As will be described below, the power absorption capability could be based on a state of charge level, i.e. the level of electric energy that can be absorbed/fed into the high voltage battery. The power absorption capability could also be a rate of electric power that can be fed into the high voltage battery, i.e. how much electric energy per time unit absorbable by the high voltage battery. Further examples of the desired charging level will be given below.

The present inventive concept is based on the insight that by estimating road topography ahead, the braking operating when arriving can be set in advance. Hence, the braking operation during the downhill slope can be determined before actually operating the vehicle in the downhill slope. By determining the brake operation beforehand can improve the overall braking performance of the vehicle, especially in terms of high voltage energy storage system charging efficiency and reduced temperature levels of the service brake arrangement. Furthermore, determining a brake operation beforehand may also enable for the use of high- voltage energy storage system brake capability in such a way as to prolong the operational lifetime of the high-voltage energy storage system. This can be achieved by using e.g. the high-voltage energy storage system to brake in such a way that temperature and energy throughput of the high-voltage energy storage system are kept at an acceptable level. Also, the present inventive concept also enables for increased operational lifetime of e.g. the service brakes as the temperature level of these brakes can be kept at lower levels. In particular, by determining a road topography of an upcoming road path operable by the vehicle, the brake power can be distributed along the downhill slope instead of initially charging the high-voltage energy storage system to its maximum level at the beginning of the downward slope and thereafter apply e.g. service brakes and auxiliary vehicle brakes.

As described above, and in some examples, the power absorption capability may be based on a state of charge level of the high voltage energy storage system before arriving at the downhill slope and a desired state of charge level of the high voltage energy storage system at the end of the downhill slope. By determining the desired state of charge level at the end of the downhill slope, the high voltage energy storage system may assume an optimum state of charge level for further operation of the vehicle when electric power is fed to the electric traction motor for propulsion. It may also be assured that the state of charge level is not reach at e.g. a mid-section of the downhill slope.

In some examples, the desired charging level may be a maximum state of charge level of the high voltage energy storage system. Hence, the state of charge when arriving at an end position of the downhill slope should here preferably be at a maximum level.

In some examples, the desired charging level may be based on a battery degradation level of the high voltage energy storage system. In some examples, the battery degradation level may be a maximum temperature level of the high voltage energy storage system obtained during charging. A technical advantage may be that a state of health of the high voltage energy storage system can remain at a high level, thereby minimizing the time period until replacement is needed. Put it differently, the operational lifetime of the high voltage energy storage system may be prolonged. By obtaining the battery degradation level, at least one of the auxiliary brake arrangement and the service brake arrangement may be controlled to intervene in the braking operation despite e.g. the fact that the state of charge level is not at its maximum if there is a risk of reducing the operational capacity of the high voltage energy storage system. Further, when the high voltage energy storage system is somewhat degraded, the throughput of electric power in the high voltage energy storage system may be reduced to preserve the high voltage energy storage system. In detail, the desired charging level is reduced when the high voltage energy storage system is determined to be degraded.

In some examples, the method may further comprise determining, by the processing circuitry, an auxiliary brake power ability level of the auxiliary brake arrangement, determining, by the processing circuitry, a first combined brake power level, the first combined brake power level being a brake power obtainable by the electric traction motor and the auxiliary brake arrangement, and controlling, by the processing circuitry, solely the auxiliary brake arrangement in conjunction with the electric traction motor for operating the vehicle at the downhill slope with the desired speed when the brake power demand level is below the first combined brake power level.

The auxiliary brake arrangement may here be controlled contemporaneously with the electric machine to obtain the desired speed. Thus, the service brake arrangement is not used when the brake power demand level is below the first combined brake power level. Overheating of the service brake arrangement may hereby be avoided, and the operational lifetime of the service brake arrangement may be extended.

In some examples, the method may further comprise controlling, by the processing circuitry, the auxiliary brake arrangement and the service brake arrangement in conjunction with the electric traction motor for operating the vehicle at the downhill slope with the desired speed when the brake power demand level exceeds the first combined brake power level.

When controlling the vehicle speed using solely the electric traction motor and the auxiliary brake arrangement is not sufficient for obtaining the desired speed, the service brake arrangement may complement the electric traction motor and the auxiliary brake arrangement. The service brake arrangement may be operated at a low temperature level in cases where the brake power demand level merely slightly exceeds the first combined brake power level.

In some examples, the method may further comprise determining, by the processing circuitry, a service brake power ability level of the service brake arrangement, determining, by the processing circuitry, a second combined brake power level, the second combined brake power level being a brake power obtainable by the electric traction motor, the auxiliary brake arrangement and the service brake arrangement, and reducing, by the processing circuitry, a set speed of the vehicle before arriving at the downhill slope when brake power demand level exceeds the second combined brake power level.

As a precautionary measure, when the processing circuitry determines that the brake power demand level exceeds the second combined brake power level, the set speed may be reduced to thereby obtain desirable brake functionalities during the downhill slope. A reduced risk of overheating the various brakes and high-voltage energy storage system may be avoided, while at the same time increasing safety as the brakes may be able to control the speed sufficiently.

In some examples, the method may further comprise dividing, by the processing circuitry, the upcoming road path into a plurality of road path sections, each road path section being associated with an individual road topography; wherein the brake power demand level is determined for each road path section.

By dividing the road path into the plurality of road path sections, the computational effort to estimate the brake power demand level along the entire upcoming road path may be reduced compared to an estimation of the brake power demand level along the entire upcoming road path. In some examples, the desired charging level of the high voltage energy storage system may be determined before initiating operation of each road path section. The processing circuitry may hereby determine if the brake power demand level will exceed the desired charging level for each road path section.

In some examples, a state of charge level of the high voltage energy storage system may be determined at a start location of each road path sections. In some examples, the method may further comprise setting, by the processing circuitry, a desired state of charge level of the high voltage energy storage system at an end position of the upcoming road path; determining, by the processing circuitry, a desired state of charge level of the high voltage energy storage system for each road path sections to arrive at the end position with the desired state of charge level; and controlling, by the processing circuitry, during operation of the upcoming road path, at least one of the auxiliary brake arrangement and the service brake arrangement in conjunction with the electric traction motor for obtaining the desired state of charge level of the high voltage energy storage system for each of the road path sections.

A backwards calculation may thus be made based on the desired state of charge level at the end position of the upcoming road path. Hence, the high voltage energy storage system should not only be able to be operated without drainage, but also to arrive at the end position with the desired state of charge level. The braking operation may thus be controlled in such a manner that this desired state of the high voltage energy storage system is obtained. In some examples, the desired state of charge level of the high voltage energy storage system for each road path section may be based on an energy consumption of a next coming road path section.

According to a second aspect, there is provided a vehicle control unit for controlling for controlling a braking operation of a vehicle, the vehicle comprising an electric traction motor and a high voltage energy storage system, wherein the electric traction motor is configured to feed electric power to the high voltage energy storage system during braking, the vehicle further comprising an auxiliary brake arrangement and a service brake arrangement, wherein the control unit comprises processing circuitry operatively coupled to the high voltage energy storage system, the electric traction motor, the auxiliary brake arrangement, and the service brake arrangement, the processing circuitry being configured to determine road topography of an upcoming road path operable by the vehicle, determine a brake power demand level for operating the vehicle at a downhill slope of the upcoming road path at a desired speed, determine a desired charging level of the high voltage energy storage system before initiating operation at the downhill slope, compare the brake power demand level with the desired charging level, and when the brake power demand level exceeds the desired charging level control at least one of the auxiliary brake arrangement and the service brake arrangement in conjunction with the electric traction motor for operating the vehicle at the downhill slope with the desired speed.

Effects and features of the second aspect are largely analogous to those described above in relation to the first aspect.

According to a third aspect, there is provided a vehicle comprising a vehicle control unit according to the above described second aspect.

According to a fourth aspect, there is provided a computer program comprising program code means for performing the method of any of the embodiments described above in relation to the first aspect when the program is run on a computer. According to a fifth aspect, there is provided a non-transitory computer readable medium carrying a computer program comprising program code for performing the method of any of the embodiments described above in relation to the first aspect when the program product is run on a computer.

Effects and features of the third, fourth and fifth aspects are largely analogous to those described above in relation to the first aspect.

The above aspects, accompanying claims, and/or examples disclosed herein above and later below may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art.

Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be readily apparent therefrom to those skilled in the art or recognized by practicing the inventive concept as described herein. There are also disclosed herein control units, computer readable media, and computer program products associated with the above discussed technical benefits.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as additional objects, features, and advantages of the present disclosure, will be better understood through the following illustrative and non-limiting detailed description of exemplary examples of the present disclosure, wherein:

Fig. 1 is lateral side view of a vehicle in the form of a truck according to an example embodiment,

Fig. 2 is a schematic illustration of an upcoming road path operable by the vehicle according to an example embodiment,

Fig. 3 is a schematic illustration of a system for controlling braking operations of the vehicle according to an example embodiment;

Fig. 4 is a diagram illustrating brake power ability levels of the various components of the vehicle according to an example, Fig. 5 is a flow chart of a method of controlling a braking operation of the vehicle according to an example embodiment, and

Fig. 6 is a schematic diagram of an exemplary computer system for implementing examples disclosed herein, according to one example.

DETAILED DESCRIPTION

The present inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary examples are shown. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein; rather, these examples are provided for thoroughness and completeness. Like reference character refer to like elements throughout the description.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

With particular reference to Fig. 1 , there is depicted a vehicle 10 in the form of a truck. The vehicle 10 is preferably an electrically propelled vehicle comprising an electric traction motor 101 connected to at least one of the wheels 103 of the vehicle 10. The electric traction motor 101 can be directly connected to the at least one wheel 103 of the vehicle 10, or connected to the at least one wheel 103 via e.g. a transmission, shaft, etc. The electric traction motor 101 is configured to receive electric power and to generate a propulsion torque during propulsion of the vehicle 10. The electric traction motor 101 is also configured to generate electric power during braking, thereby using the electric traction motor 101 as a vehicle brake. The vehicle 10 also comprises a high voltage energy storage system 104. The high voltage energy storage system 104 is arranged to feed electric power to e.g. the electric traction motor 101 during propulsion and to receive electric power from the electric traction motor 101 during braking. Furthermore, the vehicle 10 comprises a service brake 108 connected to at least one wheel 103’ of the vehicle 10. In Fig. 1, the service brake 108 is depicted as connected to the front wheel 103’ of the vehicle 10, while the electric traction motor 101 is depicted as operable to generate a torque on the rearmost wheel 103 of the vehicle. It should however be readily understood that further wheels of the vehicle may be equipped with a service brake, and other wheels may be propelled by the electric traction motor 101. The electric traction motor 101 must hence not be arranged to propel the rearmost wheel, but can instead, or as a complement, be operable to propel e.g. the front wheel 103’, etc. As is further schematically depicted in Fig. 1 , the vehicle 10 comprises an auxiliary brake arrangement 106. The auxiliary brake arrangement 106 is preferably, and as also merely schematically illustrated, electrically connected to the electric traction motor 101. The auxiliary brake arrangement 106 is thus configured to controllably receive electric power generated by the electric traction motor 101 during braking. The auxiliary brake arrangement 106 may, for example, be an electric brake resistor. As an alternative, the auxiliary brake arrangement may also be, or comprise, an air compressor configured to pressurize a flow of air. Such air compressor is preferably operated by electric power generated by the electric traction motor during braking to thereby dissipate electric energy. As a further alternative, the auxiliary brake arrangement 106 may be an air compressor in combination with an electric brake resistor. In the latter example, the air compressor is fed with electric power from the electric traction motor 101 during braking. The air compressor dissipates the electric energy by pressurizing a flow of ambient air. The pressurized air is fed to the electric brake resistor which heats the pressurized air for deliver to an air heated receiver. The electric brake resistor thus also acts to dissipate electric energy generated by the electric traction motor 101 during braking.

Moreover, the vehicle also comprises a vehicle control unit 114, in the following merely referred to as a control unit 114. The control unit 114 comprises processing circuitry operatively coupled to the high voltage energy storage system 104, the electric traction motor 101 , the auxiliary brake arrangement 106, and the service brake arrangement 108. The control unit 114 may include a microprocessor, microcontroller, programmable digital signal processor or another programmable device. The control unit may also, or instead, include an application specific integrated circuit, a programmable gate array or programmable array logic, a programmable logic device, or a digital signal processor. Where the control unit 114 includes a programmable device such as the microprocessor, microcontroller or programmable digital signal processor mentioned above, the processor may further include computer executable code that controls operation of the programmable device.

Reference is now made to Fig. 2 for a further detailed schematic illustration of the above-described components comprised within a braking system 202 of the vehicle 10. As can be seen, the braking system 202 comprises the electric traction motor 101 , the high-voltage energy storage system 104, which is preferably a high-voltage vehicle battery, the auxiliary brake arrangement 106 and the service brake 108, as well as the above described control unit 114. The control unit 114 is thus configured to receive data from e.g. the electric traction motor 101 , the high-voltage energy storage system 104, the auxiliary brake arrangement 106 and the service brake arrangement 108, and to control operation of these components. It should be understood that the braking system 202 depicted in Fig. 2 may comprise further components, such as e.g. one or more junction boxes.

As described above, and illustrated in Fig. 2, the electric traction motor 101 is configured to receive electric power from the high-voltage energy storage system 104 during propulsion, and to feed electric power to the high-voltage energy storage system 104 during braking. The electric traction motor 101 is also electrically connected to the auxiliary brake arrangement 106. The electric traction motor 101 is hereby configured to feed electric energy to the auxiliary brake arrangement 106 for energy dissipation. Although not depicted in Fig. 2, the high-voltage energy storage system 104 may also be electrically connected to the auxiliary brake arrangement 106.

As also illustrated in Fig. 2, the control unit 114 is connected to a road topography detector 204. The road topography detector 204 is configured to determine a road topography of an upcoming road path operable by the vehicle 10. The road topography detector 204 may be a global positioning system (GPS) or a global navigation satellite system (GNSS), etc. The road topography detector 204 thus transmits data indicative of the road topography of the upcoming road path to the control unit 114, whereby the processing circuitry of the control unit 114 determines a braking strategy for operating the vehicle 10 at the downhill slope at a desired speed.

In order to describe the braking operation in further detail, reference is now made to Figs. 2 - 4. As can be seen in Fig. 3, the vehicle 10 is approaching a downhill slope 302. The processing circuitry hereby preferably receives data from the road topography detector 204 and determines S1 the road topography of the upcoming downhill slope 302. The processing circuitry further determines S2 a brake power demand level 401 for operating the vehicle at the downhill slope 302 at a desired speed. The brake power demand level 401 may, for example, be based on the inclination and/or length of the downhill slope from a starting position, i.e. a crest 304 of the downhill slope 302, to an end position 306 of the downhill slope 302.

Further, the processing circuitry determines S3 a desired charging level 402 of the high voltage energy storage system 104 before initiating operation at the downhill slope 302, i.e. before arriving at the crest 304 of the downhill slope 302. According to examples, the desired charging level may be based on a power absorption capability of the high voltage energy storage system 104. The power absorption capability is preferably based on a state of charge level of the high voltage energy storage system 104 before arriving at the downhill slope, i.e. before arriving at the crest 304 of the downhill slope, and a desired state of charge level of the high voltage energy storage system 104 at the end position 306 of the downhill slope. Put it differently, the power absorption capability is in this example the available energy level in the high voltage energy storage system 104 when subsequently operating the vehicle 10 through the downhill slope 302. Also, the power absorption capability can be the rate of electric energy receivable by the high voltage energy storage system 104, i.e. how much electric power that can be received per time unit.

Further, and according to yet another example, the desired charging level 402 may be a maximum state of charge level of the high voltage energy storage system 104. Thus, the charging level 402 of the high voltage energy storage system 104 should in this example preferably be at a maximum level when arriving at the end position 306.

Furthermore, and according to an example, the desired charging level may as an alternative or as a complement be based on a battery degradation level of the high voltage energy storage system. The battery degradation level may be a maximum temperature level of the high voltage energy storage system obtained during charging when braking using the electric traction motor 101. The high voltage energy storage system 104 may thus be degraded, i.e. a state of health of the high voltage energy storage system 104 may be reduced, if the high voltage energy storage system 104 is exposed to high temperature levels, especially when exposed to high temperature levels during longer period of times. Moreover, the processing circuitry is further configured to compare the brake power demand level 401 with the desired charging level 402. Hereby, the processing circuitry may, before arriving at the crest 304, determine whether the electric power generated by the electric traction motor 101 during operation throughout the downhill slope can be absorbed by the high voltage energy storage system 104. However, when the brake power demand level 401 exceeds the desired charging level 402, the processing circuitry controls S5 at least one of the auxiliary brake arrangement 106 and the service brake arrangement 108 in conjunction with the electric traction motor 104 for operating the vehicle 10 at the downhill slope 302 with the desired speed. In detail, the processing circuitry controls the electric traction motor 101 to control the vehicle speed, whereby electric power is fed from the electric traction motor 101 to the high voltage energy storage system 104, while at the same time controls either the electric motor 101 to also feed electric power to the auxiliary brake arrangement 106 and/or to engage the at least one service brake arrangement 108.

However, should the brake power demand level 401 not exceed the desired charging level 402, the processing circuitry controls S6 solely the electric traction motor 101 to control the vehicle speed such that electric power is fed from the electric traction motor 101 to the high voltage energy storage system 104.

Furthermore, the processing circuitry may be further configured to determine an auxiliary brake power ability level 404 of the auxiliary brake arrangement 106. The brake power ability level 404 is preferably an electric power level that can be absorbed by the auxiliary brake arrangement 106 during operation of the vehicle 10 at the downhill slope. A first combined brake power level 405 can here be determined, wherein the first combined brake power level 405 is a brake power level that can be handled by the electric traction motor 101 and the auxiliary brake arrangement 106. It should however be readily understood that the auxiliary brake arrangement 106 does not necessarily need to receive its electric power from the electric traction 101. Conversely, the auxiliary brake arrangement 106 can receive its brake power from e.g. the wheels 103 or a transmission of the vehicle. In such situations, the electric traction motor 101 can be controlled to generate less electric power. When the brake power demand level 401 is below the first combined brake power level 405, the processing circuitry preferably solely controls the auxiliary brake arrangement in conjunction with the electric traction motor for operating the vehicle at the downhill slope with the desired speed. Hence, when the high-voltage energy storage system 104 in conjunction with the auxiliary brake arrangement 106 are able to handle the electric power levels generated by the electric traction motor 101 , the service brake arrangement 108 is preferably not engaged.

However, when the brake power demand level 401 exceeds the first combined brake power level 405, the processing circuitry preferably controls the auxiliary brake arrangement 106 and the service brake arrangement 108 in conjunction with the electric traction motor 101 for operating the vehicle at the downhill slope 302 with the desired speed. Thus, when the high-voltage energy storage system 104 in conjunction with the auxiliary brake arrangement 106 are not able to handle the electric power levels generated by the electric traction motor 101 , the service brake arrangement 108 are preferably also engaged.

Still further, the processing circuitry may also determine a service brake power ability level 406 of the service brake arrangement. The service brake power ability level 406 should preferably be construed as the brake power that can be handled by the service brake arrangement 106, i.e. how brake power that is absorbable by the service brake arrangement 106. Hereby, the processing circuitry may determine a second combined brake power level 407 which is a brake power obtainable by the electric traction motor, the auxiliary brake arrangement and the service brake arrangement, i.e. the total brake power that the electric traction motor, the auxiliary brake arrangement and the service brake arrangement can absorb.

If the brake power demand level should also exceed the second combined brake power level, a set speed of the vehicle 10 is preferably reduced before arriving at the downhill slope 302, i.e. before arriving at the crest 304. The downhill slope 302 is thus entered with a lower vehicle speed to be able to sufficiently handle sufficient operation of the vehicle during operation at the downhill slope.

With particular reference to Fig. 3, the processing circuitry may be further configured to divide the upcoming road path 302 into a plurality of road path sections 322, 332, 342, 352, 362, 372. Each of the plurality of road path sections is associated with an individual road topography. In other words, each of the plurality of road path sections 322, 332, 342, 352, 362, 372 comprises an individual inclination and distance. Preferably, the brake power demand level 401 may be determined for each road path section. The above described desired charging level 402, the auxiliary brake power ability level 404, service brake power ability level 406, the first combined brake power level 405 as well as the second combined brake power level 407 may also be determined for each of the plurality of road path sections. More preferably, at least the desired charging level of the high voltage energy storage system is determined before initiating operation of each road path section. A state of charge level of the high voltage energy storage system 104 may be determined at a start location of each road path sections, where the start location 331 of the second road path section 332 is indicated as an example in Fig. 3.

Furthermore, by dividing the upcoming road path 302 into a plurality of road path sections 322, 332, 342, 352, 362, 372 as depicted in Fig. 3, the processing circuitry may advantageously set a desired state of charge level of the high voltage energy storage system at the end position 306 of the upcoming road path 302. A desired state of charge level of the high voltage energy storage system 104 for each road path sections can hereby be determined in order to arrive at the end position 306 with the desired state of charge level. Thereafter, during operation of the upcoming road path, the processing circuitry may control at least one of the auxiliary brake arrangement and the service brake arrangement in conjunction with the electric traction motor for obtaining the desired state of charge level of the high voltage energy storage system for each of the road path sections. Hence, for some road path sections, the electric traction motor is solely operated for obtaining the desired speed, while for other road path sections, the auxiliary brake arrangement and/or the service brake arrangement is controlled in conjunction with the electric traction motor 101 for obtaining the desired speed.

According to an example, the desired state of charge level of the high voltage energy storage system 104 for each road path section is based on an energy consumption of a next coming road path section. Thus, a backwards calculation is executed by the processing circuitry to determine the desired state of charge level when initiating operation of a road path section.

Reference is now finally made to Fig. 6, which is a schematic diagram of a computer system 600 for implementing the above disclosed examples. The computer system 600 is adapted to execute instructions from a computer-readable medium to perform these and/or any of the functions or processing described herein. The computer system 600 may be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, or the Internet. While only a single device is illustrated, the computer system 600 may include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. Accordingly, any reference in the disclosure and/or claims to a computer system, computing system, computer device, computing device, control system, control unit, electronic control unit (ECU), the above described processing circuitry, etc., includes reference to one or more such devices to individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. For example, control system may include a single control unit or a plurality of control units connected or otherwise communicatively coupled to each other, such that any performed function may be distributed between the control units as desired. Further, such devices may communicate with each other or other devices by various system architectures, such as directly or via a Controller Area Network (CAN) bus, etc.

The computer system 600 may comprise at least one computing device or electronic device capable of including firmware, hardware, and/or executing software instructions to implement the functionality described herein. The computer system 600 may include the above described processing circuitry 602 (may also be referred to as the control unit 114, or form part of the control unit 114), a memory 604, and a system bus 606. The computer system 600 may include at least one computing device having the processor device 602. The system bus 606 provides an interface for system components including, but not limited to, the memory 604 and the processing circuitry 602. The processing circuitry 602 may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory 604. The processing circuitry 602 (e.g., control unit) may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor device may further include computer executable code that controls operation of the programmable device.

The system bus 606 may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and/or a local bus using any of a variety of bus architectures. The memory 604 may be one or more devices for storing data and/or computer code for completing or facilitating methods described herein. The memory 604 may include database components, object code components, script components, or other types of information structure for supporting the various activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory 604 may be communicably connected to the processing circuitry 602 (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory 604 may include non-volatile memory 608 (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory XX10 (e.g., random-access memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with a processing circuitry 602. A basic input/output system (BIOS) 612 may be stored in the non-volatile memory 608 and can include the basic routines that help to transfer information between elements within the computer system 600.

The computer system 600 may further include or be coupled to a non-transitory computer-readable storage medium such as the storage device 614, which may comprise, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device 614 and other drives associated with computer-readable media and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, and the like. A number of modules can be implemented as software and/or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device 614 and/or in the volatile memory 610, which may include an operating system 616 and/or one or more program modules 618. All or a portion of the examples disclosed herein may be implemented as a computer program product 620 stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device 614, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processing circuitry 602 to carry out the steps described herein. Thus, the computer-readable program code can comprise software instructions for implementing the functionality of the examples described herein when executed by the processing circuitry 602. The processing circuitry 602 may serve as a controller or control system for the computer system 600 that is to implement the functionality described herein.

The computer system 600 also may include an input device interface 622 (e.g., input device interface and/or output device interface). The input device interface 622 may be configured to receive input and selections to be communicated to the computer system 600 when executing instructions, such as from a keyboard, mouse, touch- sensitive surface, etc. Such input devices may be connected to the processing circuitry 602 through the input device interface 622 coupled to the system bus 606 but can be connected through other interfaces such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) 1394 serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system 600 may include an output device interface 624 configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system 600 may also include a communications interface 626 suitable for communicating with a network as appropriate or desired.

The operational steps described in any of the exemplary aspects herein are described to provide examples and discussion. The steps may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the steps, or may be performed by a combination of hardware and software. Although a specific order of method steps may be shown or described, the order of the steps may differ. In addition, two or more steps may be performed concurrently or with partial concurrence.

It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the inventive concepts being set forth in the following claims.