COMPUTER-IMPLEMENTED METHOD OF BRAKE MANAGEMENT
20240198808 ยท 2024-06-20
Assignee
Inventors
Cpc classification
B60L2260/20
PERFORMING OPERATIONS; TRANSPORTING
B60L2240/42
PERFORMING OPERATIONS; TRANSPORTING
B60L7/24
PERFORMING OPERATIONS; TRANSPORTING
B60L2240/70
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A computer-implemented method of brake management in an electric or hybrid electric heavy-duty vehicle that has batteries which are configured to absorb energy from regenerative braking is provided. Topographic data containing information about an upcoming downhill slope is obtained. A state of charge target (SOC target) below 100% for said batteries is determined. Based on the obtained topographic data, a total brake power required for maintaining the speed of the heavy-duty vehicle at or below a selected speed limit of the heavy-duty vehicle throughout the travel in the downhill slope is determined. The determined total brake power is in the form of at least one of regenerative braking, auxiliary braking and service braking of the heavy-duty vehicle. The speed of the heavy-duty vehicle when travelling in said downhill slope is controlled by applying said determined total brake power such that the state of charge of the batteries remains below or equal to said SOC target throughout the travel in the downhill slope.
Claims
1. A computer-implemented method of brake management in an electric or hybrid electric heavy-duty vehicle that has batteries which are configured to absorb energy from regenerative braking, the method comprising: obtaining, by a processor device of a computer system, topographic data containing information about the topography of an upcoming part of a road along which the heavy-duty vehicle is currently travelling, the topographic data including information about an upcoming downhill slope, determining, by the processor device, a state of charge target (SOC target) below 100% for said batteries, determining, by the processor device, based on the obtained topographic data, a total brake power required for maintaining the speed of the heavy-duty vehicle at or below a selected speed limit of the heavy-duty vehicle throughout the travel in the downhill slope, the determined total brake power being in the form of at least one of regenerative braking, auxiliary braking and service braking of the heavy-duty vehicle, and controlling, by the processor device, the speed of the heavy-duty vehicle when travelling in said downhill slope, by applying said determined total brake power such that the state of charge of the batteries remains below or equal to said SOC target throughout the travel in the downhill slope.
2. The computer system comprising the processor device configured to perform the method of claim 1.
3. The method of claim 1, wherein the heavy-duty vehicle comprises a cooling system for cooling said batteries and/or power electronics of the vehicle, the method further comprising: determining, by the processor device, a threshold temperature of a coolant of the cooling system, and controlling, by the processor device, the speed of the heavy-duty vehicle when travelling in said downhill slope, by applying said determined total brake power such that the temperature of the coolant remains below or equal to said threshold temperature throughout the travel in the downhill slope.
4. The method of claim 1, further comprising: determining, by the processor device, a brake power distribution of said total brake power to be applied, said determined brake power distribution being a mixture of simultaneous: regenerative braking and auxiliary braking, regenerative braking and service braking, auxiliary braking and service braking, or regenerative braking, auxiliary braking and service braking, wherein said controlling of the speed by applying said determined total brake power, comprises: applying said determined total brake power in the form of said determined brake power distribution.
5. The method of claim 4, further comprising: determining, by the processor device, based on the obtained topographic data, a maximum energy that is recoverable through regenerative braking throughout the travel in the downhill slope without exceeding said SOC target and without exceeding said speed limit, and determining, by the processor device, said brake power distribution based on said determined maximum energy.
6. The method of claim 4, the further comprising: receiving, by the processor device, ambient temperature data containing information about the ambient temperature and coolant temperature data containing information about the temperature of the coolant in the cooling system, and determining, by the processor device, said brake power distribution based on said received ambient temperature data and coolant temperature data.
7. The method of claim 6, further comprising: determining, by the processor device, the heat capacity of the coolant, and determining, by the processor device, said brake power distribution based on said determined heat capacity.
8. The method of claim 1, wherein said topographic data comprises information about the grade of the downhill slope, the method further comprising: determining, by the processor device, the total weight of the heavy-duty vehicle, including the weight of any trailing vehicle part, wherein said act of determining the total brake power required for maintaining the speed of the heavy-duty vehicle at or below the selected speed limit, comprises determining the total brake power based on the determined total weight and the grade of the downhill slope.
9. The method of claim 8, further comprising: determining, by the processor device, said maximum energy based on the determined total weight and grade of the downhill slope.
10. The method of claim 1, further comprising: determining, by the processor device, the total brake power, BP.sup.tot, based on the following relationships:
11. The method of claim 1, further comprising: determining, by the processor device, a combined brake power deliverable from regenerative braking and auxiliary braking without exceeding said SOC target, and upon determination that said deliverable combined brake power is insufficient to maintain said selected speed limit throughout the travel in the downhill slope, controlling, by the processor device, service brakes of the heavy-duty vehicle to provide additional brake power so as to maintain the speed at or below said selected speed limit throughout the travel in the downhill slope.
12. The method of claim 11, further comprising: determining, by the processor device, an aggregated brake power deliverable from regenerative braking and auxiliary braking without exceeding said threshold temperature of the coolant, and upon determination that said deliverable aggregated brake power is insufficient to maintain said selected speed limit throughout the travel in the downhill slope, controlling, by the processor device, service brakes of the heavy-duty vehicle to provide additional brake power so as to maintain the speed at or below said selected speed limit throughout the travel in the downhill slope.
13. The method of claim 1, wherein said topographic data comprises information about the length of the downhill slope, the method further comprising: determining, by the processor device, said brake power distribution based on the length of the downhill slope.
14. The method of claim 13, further comprising: determining, by the processor device, said maximum energy based on the length of the downhill slope.
15. The method of claim 1, wherein said auxiliary braking is performed by the processor device activating a mechanical retarder and/or an electric brake resistor of the heavy-duty vehicle.
16. The method of claim 1, wherein the topographic data is obtained from a Geographic Information System (GIS).
17. A vehicle comprising the processor device to perform the method of claim 1.
18. A computer program product comprising program code for performing, when executed by the processor device, the method of claim 1.
19. A control system comprising one or more control units configured to perform the method according to claim 1.
20. A non-transitory computer-readable storage medium comprising instructions, which when executed by the processor device, cause the processor device to perform the method of claim 1.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0061] With reference to the appended drawings, below follows a more detailed description of aspects of the disclosure cited as examples.
[0062]
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[0065]
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DETAILED DESCRIPTION
[0070] Aspects set forth below represent the necessary information to enable those skilled in the art to practice the disclosure.
[0071] When a heavy-duty vehicle is driving in a downhill slope, the required brake power to maintain the vehicle speed, is normally much higher compared to what is needed for braking a passenger car. For heavy-duty vehicles which are equipped with batteries that may absorb regenerative braking energy, long and/or steep downhill slopes may therefore present a challenge, since the batteries may not be able to absorb all the brake energy that is regenerated. Fully charging the batteries causes the batteries to become stressed, resulting in shorter lifetime and reduced drive range. Thus, while it is desirable to regenerate as much energy as possible, since simple service braking is not only a waste of energy but also causes the brakes to fade, there is a limit as to how much of the regenerated energy that can be absorbed, and additionally there is the aspect of maintaining good battery health by avoiding fully charging the batteries. According to the present disclosure a SOC target less than 100% is set in order to avoid stressing the batteries, and a total brake power required for maintaining the vehicle speed within a certain speed limit is determined. The determined brake power is then allocated by the processor device in such manner that the SOC of the batteries will not exceed the SOC target during the downhill travel. Thus, the processor device, may allocate brake power (of the total brake power) to regenerative braking to such extent that the SOC target is not exceeded, and allocate any remaining brake power needed to other brakes of the vehicle. Therefore, for a short and/or low grade downhill slope the entire braking may be allocated to regenerative braking if the current SOC is at a level that allows the batteries to absorb all regenerative energy without exceeding the SOC target, whereas in other cases when the current SOC is already at a high level and/or the downhill slope is longer and/or steeper, the processor device will set a lower or no regenerative brake power, and will control the auxiliary brake and/or service brake to provide a large portion of the required total brake power.
[0072]
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[0075] The vehicle may have a plurality of different input devices/systems 22, 24, 26 which may provide different types of information to the processor device 20. For simplicity,
[0076] As illustrated in
[0077] In operation, the processor device 20 will obtain topographic data from one of the input devices 22, 24, 26, such as the GIS 22. The topographic data contains information about the topography of an upcoming part of a road along which the heavy duty vehicle is currently travelling, the topographic data including information about an upcoming downhill slope (such as the downhill slope 6 illustrated in
[0078]
[0079] The different lines can be calculated based on the following relationships:
where [0080] BPtot is the total brake power, i.e. the values on the vertical axis; [0081] k is a combined efficiency coefficient which is based on the efficiencies of components such as rear-axle, gearbox, electric machine, inverter and batteries; [0082] GF is the grade force calculated as mgsin(?).Math.v, where m is the mass of the heavy duty vehicle (i.e. in
[0085] In the following discussion, it will be assumed that the vehicle can provide a brake power of 300 kW through regenerative braking. As illustrated by the arrows in
[0086] Thus, turning back to
[0087] From the above, it can be understood that the processor device 20 may determine a brake power distribution of said total brake power to be applied. The determined brake power distribution can be a mixture of simultaneous regenerative braking and auxiliary braking (engaging systems 10 and 14), or regenerative braking and service braking (engaging systems 10 and 16), or auxiliary braking and service braking (engaging systems 14 and 16), or regenerative braking, auxiliary braking and service braking (engaging all three systems 10, 14 and 16). The processor device 20 may therefore apply the determined total brake power in the form of said determined brake power distribution.
[0088] The processor device 20 may determine, based on the obtained topographic data (e.g. obtained from GIS 22), a maximum energy that is recoverable through regenerative braking (using regenerative brake system 10) throughout the travel in the downhill slope without exceeding the SOC target and without exceeding the speed limit. Based on this determined maximum energy, the processor device 20 may then determine the brake power distribution, i.e. which one or ones of the brake systems 10, 14, 16 should be engaged and how much brake power they should provide.
[0089] One of the input devices/systems 24, 26 may for instance represent an ambient temperature sensor. The processor device 20 may from receive ambient temperature data (e.g. from such an ambient temperature sensor), wherein the ambient temperature data contains information about the ambient temperature. The processor device 20 may, as mentioned previously, also be in communication with the coolant system 28. The processor device may for example receive coolant temperature data (from the coolant system 28) containing information about the temperature of the coolant in the coolant system 28. Based on the received ambient temperature data and the received coolant temperature data, the processor device 20 may suitably determine said brake power distribution.
[0090] The processor device 20 may also be configured to determine the heat capacity of the coolant. The heat capacity of the coolant may for example be stored in an electronic memory which is accessible to the processor device 20, or the processor device 20 may calculate/estimate the heat capacity of the coolant by acquiring information about how much the temperature rises for a certain amount of heat energy supplied to the coolant. Based on the determined heat capacity of the coolant, the processor device 20 may suitably determine said brake power distribution.
[0091] The topographic data (e.g. from GIS 22) may suitably comprise information about the grade of the downhill slope. The processor device 20 may determine the total weight of the heavy duty vehicle including the weight of any trailing vehicle part. Regardless of how the processor device 20 determines the total weight of the vehicle, it may suitably determine the total brake power required for maintaining the speed of the vehicle at or below the selected speed limit based on the grade of the downhill slope and based on the determined total weight. Furthermore, based on the grade of the downhill slope and based on the total weight of the vehicle, the processor device 20 may also determine the maximum energy that is recoverable through regenerative braking throughout the travel in the downhill slope.
[0092] As regards determining the total weight, the are various conceivable possibilities for the processor device 20 to obtain the relevant information. For instance, the processor device 20 may receive weight information from vehicle weighing scales on which the vehicle may stand before it sets out for its destination. Another possibility is for the processor device to receive information from load sensors of the vehicle (for example, one of the illustrated input devices/systems 24, 26 could represent one or more load sensors). A further possibility is for the processor device 20 to receive weight information by manual input, e.g. the driver having knowledge of the weight of the cargo that has been loaded onto the vehicle (for example, one of the illustrated input devices/systems 24, 26 could represent a user interface).
[0093] From the discussions above, it should be understood that the processor device 20 may determine to provide a combined brake power selected from the different brake systems 10, 14, 16. Suitably, the service brake system 16 may engaged as a last resort, if the other brake systems 10, 14 are insufficient for a certain scenario. For instance, the processor device may determine a combined brake power deliverable from regenerative braking (using regenerative brake system 10) and auxiliary braking (using auxiliary brake system 14) without exceeding the SOC target. Upon determination that the deliverable combine brake power is insufficient to main the selected speed limit throughout the travel in the downhill slope (and without exceeding the SOC target), the processor device 20 may control the service brakes (of the service brake system 16) to provide additional brake power so as to maintain the speed at or below the selected speed limit throughout the travel in the downhill slope. Similarly, the processor device 20 may determine an aggregated brake power deliverable from regenerative braking (using regenerative brake system 10) and auxiliary braking (using auxiliary brake system 14) without exceeding said threshold temperature of the coolant of the cooling system 28. Upon determination that said deliverable aggregated brake power is insufficient to maintain said selected speed limit throughout the travel in the downhill slope (and without exceeding the threshold temperature), the processor device 20 may control the service brakes (of the service brake system 16) to provide additional brake power so as to maintain the speed at or below the selected speed limit throughout the travel in the downhill slope.
[0094] As discussed previously, the length of the downhills slope may be relevant for determining the maximum recoverably energy in the downhill slope. The topographic data (e.g. from GIS 22) may suitably comprise information about the length of the downhill slope. The processor device 20 may therefore determine the brake power distribution based on the length of the downhill slope. Furthermore, the processor device 20 may determine the said maximum energy based on the length of the downhill slope. Hereby, the processor device 20 may determine how much of the brake power can be allocated to regenerative braking so that the SOC target is not exceeded when energy is recovered in the batteries 12 through regenerative braking.
[0095]
The above mentioned steps do not necessarily need to be performed in the stated order. For instance, step S1 may be performed before, simultaneously with or after step S2.
[0100]
[0101] 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 a processor device 602 (may also be referred to as a control unit), a memory 604, and a system bus 606. The processor device 602 may, for instance, correspond to the processor device 20 of
[0102] 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 processor device 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 610 (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 processor device 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.
[0103] 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.
[0104] 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 processor device 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 processor device 602. The processor device 602 may serve as a controller or control system for the computer system 600 that is to implement the functionality described herein.
[0105] 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 processor device 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.
[0106] 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.
[0107]
[0108] Particularly, the processing circuitry 710 is configured to cause the processor device 700 to perform a set of operations, or steps, such as the method discussed in connection to
[0109] The storage medium 730 may also comprise persistent storage, which, for example may be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.
[0110] The processor device 700 may further comprise an interface 720 for communications with at least one external device such as temperature sensor, speed sensor, GPS system, batteries and the brake systems discussed herein. As such, the interface 720 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline or wireless communication.
[0111] The processing circuitry 710 controls the general operation of the processor device 700, e.g. by sending data and control signals to the interface 720 and the storage medium 730, by receiving data and reports from the interface 720, and by retrieving data and instructions form the storage medium 730. Other components, as well as the related functionality, of the processor device 700 are omitted in order not to obscure the concepts presented herein.
[0112]
[0113] The terminology used herein is for the purpose of describing particular aspects 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.
[0114] 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.
[0115] 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.
[0116] 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.
[0117] 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.