Method and system for regenerative braking

Abstract

The invention relates to a method (1) for regenerative braking of battery electric vehicles, in which, for a recuperation process of a vehicle, an optimized brake actuation of a recuperation brake is calculated as a function of the vehicle speed and at least one further parameter, wherein the calculated optimized brake actuation is output to a driver of the vehicle or to a driver assistance system of the vehicle. Such recuperation processes can be improved by including at least one additional parameter that specifies the current road condition, such as dry, wet, snowy, icy, sandy, potholes, gravel surface, oil slick, and / or a current road scenario, such as traffic density, clear road, congestion, bottleneck, construction site, mobile traffic light, accident, slow vehicle, obstacle, of a preceding road section to be traversed by the recuperating vehicle during the recuperation process.

Description

[0001] The present invention relates to a method for regenerative braking of battery-electric vehicles according to the preamble of claim 1. The invention also relates to a system for regenerative braking of battery-electric vehicles in which the method is applied. The invention further relates to a battery-electric vehicle suitable for use in the system or with the method. Finally, the invention relates to software for implementing the method.

[0002] In battery-electric vehicles, braking is commonly performed regeneratively or recuperatively wherever possible. Regenerative braking converts the vehicle's kinetic energy into electrical energy, which can be stored in a vehicle battery. Regenerative braking can thus extend the range of the battery-electric vehicle.

[0003] A generic method is known from DE 10 2011 088 478 A1 and requires that, for a vehicle's recuperation process, an optimized braking application of a regenerative brake is calculated depending on the vehicle speed and at least one other parameter. The calculated optimized braking application is then output to a driver (male / female / diverse) of the vehicle or to a driver assistance system of the vehicle. The goal of the recuperation process is typically to maintain the current vehicle speed when driving downhill or to reduce the current vehicle speed to a desired speed specified by the driver or driver assistance system.While a conventional regenerative braking process issues a predetermined braking action, the generic braking process takes into account at least one additional parameter, allowing for the calculation of an optimized braking action. The additional parameter can be, for example, a time or location at which the desired speed is to be reached. By taking into account navigation data from the road on which the vehicle is traveling, the braking action can be optimized. For example, knowledge of the length and gradient of an upcoming downhill slope can be taken into account to calculate an optimized braking action.

[0004] The present invention addresses the problem of further improving such a method and a system for regenerative braking, with a particular focus on increased recuperation performance. A battery-electric vehicle and software that are used or can be used in the method and system are also to be specified.

[0005] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The invention is based on the general idea that the at least one parameter taken into account when calculating the optimized braking application for the respective recuperation process includes a current road condition and / or a current road scenario of a road section located ahead of the vehicle and traversed during the recuperation process. By taking the current road condition into account, for example, the achievable static friction between the vehicle's wheels and the road surface of the road section can be more accurately considered. The current road condition can, for example, contain information about whether the road surface of the respective road section is currently dry or wet, snowy, icy, or sandy.Furthermore, the information about the road condition can include the presence of potholes, in particular pothole density and / or pothole size, the presence of chippings, or oil slicks. It is obvious that these different road conditions have a significant influence on the braking behavior of the vehicle. Taking this information about the current road condition into account enables significantly improved optimization of brake application. Additionally or alternatively, taking the current road scenario into account can also have a significant influence on the actually achievable braking deceleration of the vehicle in the road section in question. Information about the current road scenario can, for example, be the current traffic density or information about whether the road section is clear of traffic or whether there is currently a traffic jam.Furthermore, current bottlenecks, construction sites, mobile traffic lights, a recent accident, a slow-moving vehicle, such as an agricultural vehicle or a horse-drawn carriage, or another obstacle can represent information about the current road scenario. All of this information about the road scenario significantly influences the possibility of braking. Taking the road scenario into account thus enables improved optimization of braking. This road information or road data regarding the current road conditions and / or the current road scenario is time-dependent and therefore variable, and cannot be provided, for example, in a conventional navigation device.

[0007] A regenerative braking system is a vehicle brake that enables regenerative braking, in which the vehicle's kinetic energy is converted into electrical energy and fed into a vehicle battery. This type of regenerative braking system is typically an electric motor drive of the vehicle that operates as a generator.

[0008] In this context, the term "current" should be understood relatively, as it depends on the type of road condition or road scenario in question. For example, a wet road in otherwise dry weather may dry quickly, meaning that this road condition does not last long. In contrast, a road condition characterized by a series of potholes may last a long time. A slow-moving vehicle may also represent a relatively short-term scenario, whereas an accident at a roadworks site may last a comparatively long time.

[0009] According to an advantageous embodiment, the current road condition and / or the current road scenario can be detected using sensors located on other vehicles that have already driven through the road section. The recuperating vehicle, i.e., the vehicle that is to perform a recuperation process, i.e., regenerative braking, in the road section in question, can then communicate directly with these other vehicles, for example, via so-called car-to-car communication. For such direct communication, the other vehicles are located in the vicinity of the recuperating vehicle. This ensures that the road data recorded by these other vehicles, which correlate with the road condition or road scenario, is current.Additionally or alternatively, the recuperating vehicle can communicate with an external computer system to which the other vehicles have transmitted road data that correlates with the current road conditions and / or the current road scenario. Such an external computer system can, for example, be a cloud-based backend comprising one or more computers and / or one or more servers. The road data stored in the computer system is saved with a timestamp, allowing the recuperating vehicle to retrieve the current road data, i.e., the current road conditions and / or the current road scenario, for the road section in question.In other words, this embodiment utilizes the on-board sensor technology found in modern vehicles to acquire road data, which is then provided to neighboring vehicles and transmitted to the computer system so that the road data can also be made available to any other vehicle. By using a plurality of vehicles to acquire road data, time-dependent conditions can be captured, making it possible to provide current road data.

[0010] Furthermore, according to an advantageous embodiment, it is also possible for the recuperating vehicle to take into account additional road data in the form of further additional boundary conditions provided by stationary IoT devices. IoT stands for Internet of Things. Such IoT devices can be located along the road on which the vehicle is traveling. For example, these can be weather stations. The additional boundary conditions can be, for example, a current wind speed as well as a current rain or fog density.

[0011] According to an advantageous embodiment, it can be provided that vehicles transmit road data about the current road conditions and / or the current road scenario from a plurality of roads to the computer system. The road data is then processed in the computer system by an algorithm with artificial intelligence and prepared in such a way that vehicles calculating the optimized braking application along a specific road section for a recuperation process can retrieve the road data about the current road conditions and / or the current road scenario for this specific road section. Since this involves a very large number of vehicles and a very large number of different road sections, an extremely large amount of data can be processed here. An algorithm with artificial intelligence is suitable for the meaningful preparation of this data.

[0012] It is worth noting that the time interval between the recording of road data and the retrieval of current road data usually varies, making it necessary to estimate or predict whether the stored road data is still sufficiently up-to-date to be provided as current road data. A particular advantage in this context is that the recuperating vehicle ultimately actually drives through the respective road section and, using its on-board sensors, can record the actual current road data and transmit it to the computer system. The algorithm can then compare the provided, i.e., virtually predicted current road data with the actual road data in order to adapt the calculation process if necessary. In other words, the algorithm is constantly learning, which means that the quality of the current road data provided is constantly improving.

[0013] A system according to the invention for regenerative braking of battery-electric vehicles comprises a computer system that manages road data on the current road conditions and / or the current road scenario of a plurality of roads. The system comprises several vehicles that communicate with the computer system to carry out the method of the type described above, i.e., vehicles that collect current road data and transmit it to the computer system, and vehicles that query current road data for regenerative braking. For this purpose, the system comprises a communication device that enables communication for data exchange between the computer system and the vehicles.

[0014] A battery-electric vehicle according to the invention comprises a vehicle battery, a regenerative braking system, and a communication device for communicating with other vehicles and / or with a computer system. Furthermore, the vehicle is equipped with a control device configured to carry out the method according to one of claims 1 to 3.

[0015] In the present context, a ‘configuration’ is synonymous with a ‘design’ and / or ‘arrangement’ and / or ‘programming’, so that the phrase ‘configured so that’ is synonymous with the phrase ‘designed and / or arranged and / or programmed so that’.

[0016] A software according to the invention carries out the method of the type described above when it runs in a control device of a battery-electric vehicle which has a vehicle battery, a recuperation brake and a combination device for communication with other vehicles and / or with a computer arrangement.

[0017] Further important features and advantages of the invention emerge from the subclaims, from the drawing and from the associated description of the figures based on the drawing.

[0018] It is understood that the features mentioned above and those to be explained below can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention as defined by the claims. Components mentioned above and those to be mentioned below of a higher-level unit, such as a device, a device, or an arrangement, which are designated separately, may form separate parts or components of this unit or be integral areas or sections of this unit, even if this is shown differently in the drawing.

[0019] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0020] The only Fig. 1 shows a schematic flow diagram illustrating a method for regenerative braking of battery-electric vehicles.

[0021] Accordingly Fig. 1, a method 1 for regenerative braking of a battery-electric vehicle comprises a step 2 in which method 1 is started. Using method 1, an optimized braking actuation of a regenerative brake for optimized recuperation is calculated for a recuperation process of a vehicle depending on the vehicle speed and at least one further parameter. The at least one parameter taken into account here is at least a current road condition and / or at least a current road scenario. Other parameters that can be taken into account include, for example, the current vehicle weight, the road gradient, and the desired speed.

[0022] The road condition can be, for example, dry, wet, snowy, icy, sandy, potholes, gravel, or oil slicks. The current road scenario can be, for example, heavy traffic, clear road, traffic jam, bottleneck, construction site, mobile traffic light, accident, slow vehicle, or obstacle. The road condition and road scenario refer to a section of road ahead that the recuperating vehicle will travel through during the recuperation process.

[0023] In step 3, the section of road ahead that the recuperating vehicle is likely to travel through during the recuperation process is first determined. The vehicle can be equipped with a navigation system for this purpose, so that it is clear which road the vehicle is currently on and which section of road lies ahead. When navigation is activated, the vehicle knows the vehicle's route to the respective destination and thus all road sections that still have to be traveled. The aim of braking the vehicle can, for example, be to maintain a preset vehicle speed or to reach a reduced desired speed within a predetermined distance or up to a predetermined location, e.g. a town entrance with a reduced permissible maximum speed, and / or up to a specific time at which the reduced desired speed is to be reached.

[0024] In step 4, the current road data is retrieved. The current road data correlates with the current road conditions and / or the current road scenario and can optionally contain additional data that could influence braking. The road data can be retrieved via near-field communication, in which the recuperating vehicle queries or receives road data from other vehicles that are in the vicinity of the recuperating vehicle and that have already traveled the road section in question. Likewise, the recuperating vehicle can communicate with an external computer system that provides this road data to determine the current road data.

[0025] In step 5, the optimized braking application of the vehicle's regenerative braking system is calculated. The current storage capacity of the vehicle's battery can be taken into account. It can also be considered whether greater deceleration over a shorter period of time can generate more electrical energy than lesser deceleration over a longer period of time. At the same time, the current road data is taken into account. For example, the current road conditions can reduce the possible deceleration if the current road conditions indicate an increased risk of skidding. Furthermore, the current road scenario can affect the available deceleration time, for example, if an obstacle is detected in the road ahead.

[0026] In step 6, the calculated optimized brake application is output to a driver of the vehicle or to a driver assistance system of the vehicle. In step 7, method 1 is terminated.

[0027] The road data requested by the recuperating vehicle in step 4 is collected with the help of other vehicles that have already traveled the road section. Modern vehicles are equipped with a variety of sensors that enable the current road conditions and / or road scenario to be recorded. Through near-field communication, the recuperating vehicle knows the vehicles in its surroundings. This makes it easy to determine whether another nearby vehicle has just traveled the road section in question and can provide current road data. If so, the recuperating vehicle receives the required road data from this other vehicle. Additionally or alternatively, the recuperating vehicle can query the computer system for the current road data.Since a large number of vehicles move along all roads, constantly recording current road data and transmitting it to the computer system, more or less current road data is available for many road sections. With the help of an appropriate algorithm, in particular based on artificial intelligence, the computer system can process the large amount of incoming road data in such a way that it can be easily and quickly made available to recuperating vehicles that require current road data from specific road sections. The algorithm can, in particular, group road conditions and / or road scenarios according to whether they are usually only present for a short time or can persist for longer. For example, it can be expected that a wet road surface will not stay wet for long in dry weather. In contrast, a newly established construction site can remain wet for a longer period.The use of artificial intelligence to process this road data makes sense because artificial intelligence, or the algorithm behind it, can continuously check and verify its calculations and predictions using new road data. This also creates the opportunity to continuously improve the predictions with regard to the timeliness of the road data.

[0028] The computer system can also consider additional data that may affect the braking process. For example, extreme weather conditions, which can certainly occur locally, can drastically reduce the possible vehicle speed for safety reasons, such as heavy rain and / or strong crosswinds and / or dense fog. The optimized brake application can take this into account, for example, by reaching a reduced desired speed sooner than would be necessary under normal weather conditions. In conjunction with a driver assistance system, a lower vehicle speed can also be specified as the desired speed. Such additional data can be transmitted to the computer system, for example, via weather stations and the like.There may also be a variety of IoT devices along the streets, such as surveillance cameras, which can be used to collect additional data and transmit it to the computer system.

[0029] A system for regenerative braking of battery-electric vehicles accordingly comprises a computer arrangement that manages road data on the current road conditions and / or the current road scenario of a plurality of roads, as well as a plurality of vehicles that, on the one hand, continuously record road data and transmit it to the computer arrangement and, on the other hand, query the current road data from the computer arrangement for regenerative braking. Communication for data exchange between the computer arrangement and the vehicles is enabled via a corresponding communication device. Battery-electric vehicles that use this system or method 1 have a vehicle battery, a regenerative brake, and a communication device for communicating with other vehicles and / or with the computer arrangement. These vehicles are also equipped with a control device configured to implement method 1.Method 1 can be implemented using software that carries out the method when it runs in a control device of a battery-electric vehicle. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2011 088 478 A1

[0003]

Claims

[1] Method (1) for regenerative braking of battery-electric vehicles, - in which an optimised braking actuation of a recuperation brake for optimised recuperation is calculated for a recuperation process of a vehicle depending on the vehicle speed and at least one further parameter, - in which the calculated optimized brake application is output to a driver of the vehicle or to a driver assistance system of the vehicle, characterized by , - that the at least one further parameter comprises a current road condition, such as dry, wet, snowy, icy, sandy, potholes, chippings, oil slick, and / or a current road scenario, such as traffic density, clear road, traffic jam, bottleneck, construction site, mobile traffic light, accident, slow vehicle, obstacle, of a road section ahead that the recuperating vehicle has to travel through during the recuperation process. [2] Method (1) according to claim 1, characterized by , - that the current road condition and / or the current road scenario is recorded by sensors located on other vehicles that have already passed through the road section, - that the recuperating vehicle communicates directly with the other vehicles and / or with a computer system to which the other vehicles have transmitted road data that correlates with the current road conditions and / or the current road scenario. [3] Method (1) according to claim 2, characterized by , - that vehicles transmit road data about the current road conditions and / or the current road scenario from a number of roads to the computer system, - that the road data in the computer system are processed by an algorithm with artificial intelligence and prepared in such a way that vehicles which calculate the optimised braking action along a specific road section for a recuperation process can retrieve the road data on the current road condition and / or the current road scenario of that specific road section. [4] System for regenerative braking of battery-electric vehicles, - with a computer arrangement that manages road data on the current road conditions and / or the current road scenario of a plurality of roads, - with vehicles which communicate with the computer arrangement to carry out the method according to one of claims 1 to 3, - with a communication device that enables communication for data exchange between the computer arrangement and the vehicles. [5] Battery electric vehicle, - with a vehicle battery, - with a recuperation brake, - with a communication device for communication with other vehicles and / or with a computer arrangement, - with a control device configured to carry out the method according to one of claims 1 to 3. [6] Software which carries out the method according to one of claims 1 to 3 when it runs in a control device of a battery-electric vehicle which has a vehicle battery, a regenerative brake and a communication device for communication with other vehicles and / or with a computer arrangement.

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