DE102011088478A1 - Method for recuperation of brake energy in vehicle, involves outputting predetermined activation of brake device based on computed recuperation function to vehicle rider or vehicle driver assistance system - Google Patents

Abstract

The present invention relates to a method for recuperation of braking energy, depending on the speed of the vehicle and depending on a further parameter, in particular depending on a target point at which the vehicle is to have a predetermined speed, a predetermined operation of a brake with a recuperation function for a desired, in particular optimal recuperation is calculated, and wherein the predetermined actuation of the brake is output to a driver or a driver assistance system.

Description

The invention relates to a method for recuperation of braking energy according to claim 1 and a control device for carrying out the method according to claim 15.

State of the art

Various methods for recuperation of braking energy are known in the prior art. For example, it is off DE 10 2009 028 751 A1 a navigation device is known in which information for controlling a recuperation of braking energy for a vehicle battery are taken into account.

Disclosure of the invention

The object of the invention is to provide an improved method for recuperation of braking energy.

The object of the invention is achieved by the method according to claim 1 and by the control device according to claim 15.

Further advantageous embodiments of the invention are specified in the dependent claims.

The described method has the advantage that an improved recuperation of braking energy is made possible. This is achieved by calculating a predetermined actuation, in particular a predetermined pressure on the brake pedal of the brake, for a desired, in particular optimal recuperation, and that the predetermined actuation is output to a driver or a driver assistance system. Thus, the driver or the driver assistance system has the opportunity to optimally perform the operation of the Rekuperationsbremse. Upon actuation of the brake pedal or an actuation of the brake system, only the Rekuperationsbremse is first used up to a certain pressure on the brake pedal. Only then, i. with a stronger pressure on the brake pedal, the mechanical brake is switched on, which does not convert the braking energy back into electrical energy. The transition between the intervention of the recuperation brake and the additional intervention of the mechanical brake is not known to the driver in the prior art. Thanks to the new method, the driver or the driver assistance system have the opportunity to optimally utilize the power of the recuperation brake or to activate the mechanical brake. This allows an improved recovery of the braking energy.

In a further embodiment, the predetermined actuation is visually, acoustically and / or haptically displayed to the driver via an output device. This provides a simple indication of a transition between the pure deceleration by the recuperation brake and the additional deceleration by the mechanical brake.

In a further embodiment, when determining the destination point, data of a digital map, in particular data about a location lying ahead with a limitation of the speed, are taken into account. Thus, it is possible to achieve an optimal determination of the target point at which the vehicle should have a predetermined speed.

In a further embodiment, in the calculation of the predetermined actuation of the brake, an information of the digital map is taken into account via an incline of a track section lying ahead. Thus, an optimized determination of the distance in which the brake is actuated, and the type of operation of the brake, in particular the pressure on the brake pedal, are determined.

In a further embodiment, the predetermined actuation of the brake is selected such that a maximum load of the recuperation brake is not exceeded if a target point is not present. This ensures that the maximum possible energy is automatically recovered by the braking process using the recuperation brake.

In a further embodiment, the recuperation brake has different efficiencies depending on the type of operation of the brake. The different efficiencies are taken into account when calculating the predetermined brake application to increase energy recovery. Thus, a further increase of the recovered energy is achieved.

In a further embodiment, a recommended distance or a recommended time for actuating the brake is determined. The route or the time duration, in particular the beginning and the end of the route are communicated to the driver or the driver assistance system. Thus, an optimized utilization of the available route for actuating the Rekuperationsbremse is possible.

In another embodiment, a destination is determined at which the vehicle should have a predetermined speed. The destination point is communicated to the driver assistance system, in particular an automatic cruise control. Thus, an optimized utilization of the Rekuperationsbremse also using a driver assistance system allows.

In a further embodiment, a digital map is provided, wherein a route calculation is performed between a starting point and a destination point. When calculating the route, a recovery of energy via the recuperation brake is taken into account. Preferably, in the route calculation, a predetermined energy consumption is desired, in particular a minimization of the energy consumption. For example, a minimization of the energy consumption can be achieved by accepting a lengthened compared to a minimum distance driving route and / or at the expense of a lengthened compared to a minimum driving time travel time. Depending on the selected embodiment, values for the extended route and / or the extended travel time can be predefined by a driver via a corresponding input.

In particular, the efficiency of the recuperation brake is taken into account as a function of the extent of the actuation, in particular as a function of the pressure on the brake pedal during route planning.

In another embodiment, the driver may specify via an input whether increased energy recovery via the recuperation brake should be performed at the expense of the average speed. This determination is taken into account in the route planning and / or in the determination of the target point and / or in the determination of the braking distance or braking time. This allows individual use of the recuperation brake.

The parameters for the use of the Rekuperationsbremse can also be transmitted to the vehicle via a wireless connection and be taken over by the control unit. Thus, the parameters can be set by a central office and the vehicle can be transmitted wirelessly. Thus, the parameters can be determined depending on other conditions that are unknown to the vehicle. For example, depending on the order situation, a forwarding agency for a vehicle fleet may have a shorter journey time / route or lower energy consumption, i.e., less than 10%. give a higher energy recovery by the Rekuperationsbremse.

The invention will be explained in more detail below with reference to FIGS. Show it:

1 in a schematic representation of a vehicle; and

2 a diagram of the efficiency of the Rekuperationsfunktion the brake.

1 shows a schematic representation of a vehicle 1 that a brake 2 that has a wheel 3 assigned. Furthermore, a control unit 4 provided that with a data storage 5 connected is. There is also an interface 6 provided to output information to a driver or to receive information from a driver. the interface 6 is also with the controller 4 connected. Furthermore, a driver assistance system 7 provided, depending on the selected driver assistance function, the brake 2 actuated. There is also a brake pedal 8th provided by the operation of the brake 2 is activated. The brake 2 is shown only schematically and includes both a pure mechanical brake and a Rekuperationsbremse. With the mechanical brake, the braking energy is destroyed. In the recuperation brake, the braking energy is converted into electrical energy and in a battery 15 , which represents, for example, the vehicle battery stored. Depending on the type of operation of the brake pedal in particular depending on the pressure on the brake pedal and / or the pedal travel either only the recuperation brake is used or in addition to the recuperation brake and the mechanical brake. Up to a certain pressure on the brake pedal or a certain pedal travel only the Rekuperationsbremse is actuated. After exceeding the specific pedal travel or the particular pedal pressure, the mechanical brake is additionally activated. The beginning of the activation of the mechanical brake can be displayed to the driver visually, acoustically or haptically, for example via the brake pedal. The driver assistance system 7 is also with the control unit 4 connected. Furthermore, a navigation system 11 provided, with which a route planning from a starting point to a destination point of a digital map can be performed.

Furthermore, there is a sensor 12 provided, the operating parameters of the vehicle, such as the speed or a location position, etc. the control unit 4 , the driver assistance system 7 and the navigation system 11 provides. Furthermore, a communication device 13 be provided, over which the control unit 4 Information about the braking process, such. B. the starting point of the braking, the target point of the braking and / or the braking status to more, in particular following vehicles emits.

Furthermore, via the communication device 13 Data, information and parameters for the actuation of the brake can be obtained from an external computing unit.

2 shows in a schematic diagram, the amount of braking energy E, via an operating pressure p of the brake pedal 8th from the recuperation function of the brake 2 is recovered, in the form of an efficiency curve nine , In the illustrated embodiment, up to a second actuation path p2, only the recuperation function of the brake 2 activated. The efficiency of the recuperation function is not the same as the actuating pressure, but is higher in a first section up to a first actuating pressure p1 than at a larger actuating pressure. From the second operating pressure p2, in addition to the recuperation function of the brake 2 also activates the purely mechanical function of the brake. The purely mechanical braking function is with the characteristic curve 10 shown in dashed lines. Depending on the selected embodiment of the brake 2 The brake may also have a different characteristic for the recuperation function and the purely mechanical braking function. Corresponding data are in the data memory 5 stored.

In most recuperation brakes, the brake energy recovery efficiency decreases as the brake pedal pressure increases. This is corresponding 2 stored as efficiency curve in the data memory.

A basic idea of the invention is to optimize the recuperation function during braking, i. H. with the highest possible efficiency, exploit, in particular without an unwanted mechanical braking effect of the brake is activated. For example, the braking distance can be extended for a higher recovery at the expense of average speed.

For this purpose, the corresponding operation, ie the pressure on the brake pedal and / or the path of the brake pedal, with a driver, the brake pedal 8th can operate without the mechanical brake function of the brake to be notified to the driver. This is done, for example, haptically via a feedback by the brake pedal 8th or a vibration of the steering wheel. In addition, this information can also be output acoustically via a loudspeaker. In addition, the information about the transition from the pure recuperation brake to the additional mechanical brakes can also be output visually via a corresponding display. In addition, the corresponding operation of the brake and the driver assistance system 7 be transmitted.

The driver can now press the brake pedal so hard during braking that he only uses the maximum recuperation function of the brake and not additionally the mechanical braking function.

The indication of the transition between the pure recuperation function of the brake and the additional mechanical function of the brake is provided by the controller 4 issued or the driver assistance system 7 transmitted. In a further embodiment, the controller calculates 4 taking into account data from a digital map or taking into account other environmental data, a destination point at which the vehicle is to have a predetermined speed. For example, using a camera at a specified distance, a traffic sign with a speed limit can be detected. In addition, when determining the destination point, data of a digital map, in particular data about a location ahead with a limitation of the speed, can be taken into account.

According to the calculated destination point is from the controller 4 an actuation of the brake 2 calculated in such a way that on the one hand, a maximum energy on the recuperation function is recovered and on the other hand, the vehicle at the target point has the desired speed. The corresponding actuation is likewise displayed to the driver or output to the driver assistance system.

The driver assistance system can be designed, for example, in the form of an automatic cruise control or in the form of an automatic distance control, with the driver assistance system correspondingly taking into account the predetermined actuation for the brake transmitted by the control device. In addition, the driver assistance system 7 even on a Rekuperationskennlinie nine the brake 2 and take appropriate account of the automated braking processes to achieve optimized brake recovery. The driver assistance system has, for example, its own arithmetic unit which performs the tasks of the driver assistance system.

In a further embodiment, the current delay mode is e.g. notified via a vehicle-to-vehicle data connection subsequent vehicles, so that they can adjust to the braking maneuver or adjust their own braking strategy.

In a further embodiment, the navigation system takes into account 11 in the route calculation, an optimized recuperation braking strategy. Preferably, in the route calculation, a predetermined energy consumption is sought, in particular a minimization of the energy consumption or a minimization of the energy consumption at the expense of a lengthened compared to a minimum distance driving route and / or below Acceptance of a compared to a minimum travel time extended travel time. The predetermined extended travel distance and / or the extended travel time can be, for example, 5% of the shortest travel distance and / or 5% of the shortest travel time. In addition, the extended driving distance and / or the extended driving time can be entered individually by the driver.

In addition, the driver can use the interface 6 specify a desired strategy and / or a desired amount of recovered energy for energy recovery or activation or deactivation of a recuperation braking strategy to the navigation system 11 report. For example, the navigation system 11 consider the recuperation function during route planning in order to achieve optimal energy recovery. In addition, the navigation system can output the route planning to the driver, indicating the recovered energy and stating a shorter and / or shorter distance route. In this embodiment, the driver can select one of the offered routes by a corresponding input. The efficiency of the recuperation brake is also taken into account.

An advantage of the described method is that an improved, in particular optimal energy recovery during braking while maximally possible speed can be achieved. For example, a cruising speed, ie an average speed, could be as high as possible. In addition, before a braking operation, the speed could be as long as possible before a short-term, but for the recovery of energy by means of Rekuperationsbremse efficient braking takes place. Thus, an unnecessary braking and deceleration of the flowing traffic can be avoided. In addition, the driver receives information about the optimal braking point, ie the optimal brake pressure on the brake pedal 8th in order to be able to optimally utilize the recuperation function of the brake. Furthermore, braking can be performed with optimized braking energy recovery using a driver assistance system.

In another embodiment, the navigation system accesses data from a digital map that contains data about speed-limited road sections. The road sections with speed limits are taken into account to calculate the destination point. For this purpose, the data is either the control unit 4 provided or the destination point is in the navigation system 11 determined yourself. Furthermore, data about a slope or a slope of a route section ahead can be taken into account in the route planning and / or in the determination of the destination and / or in the determination of the predetermined operation and / or in the determination of the beginning of the braking.

The control unit 4 determined from the current vehicle speed and other relevant vehicle characteristics, such as the efficiency curve of the recuperation function of the brake 2 and preferably taking into account characteristics of the traveled road, such as grade, preferably taking into account a position of a point with a speed limit or a speed limit (such as in a curve) and the value of the speed limit, a brake pressure with which the brake pedal 8th should be actuated in order to achieve optimal recovery of the braking energy, ie optimal use of the Rekuperationsfunktion. Preferably, a braking distance or a braking time is calculated, wherein the beginning of the braking, the end of the braking and the optimal pressure on the brake pedal is displayed to the driver. Depending on the situation, the brake pressure may change during braking. If, for example, there is no information to determine a position ahead with a speed limit, the control unit determines 4 as pedal pressure, the pressure at which the recuperation brake is actuated to the maximum, without activating the mechanical braking function. In addition, depending on the efficiency curve of the recuperation function during braking, the brake pressure may vary to recover maximum energy.

In a further embodiment, the control unit determines 4 a minimum distance from the target point at which the vehicle is to have a desired speed, the minimum distance being set such that optimum use of the recuperation function of the brake is sufficient to achieve deceleration of the vehicle to a further desired speed to the target point. The minimum distance from the target point represents the starting point of the braking process, which is optimal for efficient energy recovery. A residual distance between the start of the braking and the target point is displayed to the driver when approaching, for example graphically by means of an indicator. The display can also be made optically or haptically. The minimum distance may be, for example, 50 m before the target point speed limit (eg 50 km / h). The minimum distance depends on the speed of the vehicle and the other desired speed at the destination point. In the example, the desired speed is 50 km / h at the target point of the speed limit. Furthermore, for the determination of the minimum distance, the efficiency curve of the Rekuperationsbremse be considered. Thus, the minimum distance is set so that a maximum recovery of the braking energy is possible.

In a further embodiment, the individual parameters can be set via telematics system via the communication interface of an external processing unit. As a result, it can be determined for a vehicle or a vehicle fleet, for example, whether the vehicles should have a higher average speed or recover more energy. For example, the braking distance can be shortened to the destination at the expense of energy recovery. This achieves a higher average speed. If more energy to be recovered, then the braking distance is extended in favor of the efficiency of Rekuperationsbremse. This reduces the average speed.

In a further embodiment, the control unit communicates with the driver assistance system 7 , which includes, for example, an automatic braking and control device, such as a cruise control, and tells the driver assistance system the target point, ie the starting point of the braking and the predetermined operation of the brake. The braking is done by the driver assistance system 7 carried out. Also in this case, the brake is operated so that a desired energy recovery using the Rekuperationsbremse done. Depending on the specification, increased energy recovery at the expense of speed can also be achieved with the help of the driver assistance system. Furthermore, the control unit notifies the driver assistance system of the optimum times for the start and end of the braking process. The driver assistance system will take this information into account for energy-efficient brake control.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• DE 102009028751 A1 [0002]

Claims (15)

A method for recuperation of braking energy, wherein depending on the speed of the vehicle and depending on a further parameter, a predetermined operation of a brake with a recuperation function for a desired recuperation is calculated, and wherein the predetermined operation of the brake is output to a driver or a driver assistance system. The method of claim 1, wherein the predetermined operation is displayed visually or acoustically via an output device or haptically via a brake pedal to the driver. Method according to one of the preceding claims, wherein a destination point is used as a further parameter at which the vehicle is to have a predetermined speed. The method of claim 3, wherein in a determination of the destination point data of a digital map, in particular data about a location ahead with a limit of the speed are taken into account. Method according to one of the preceding claims, wherein in the calculation of the predetermined operation of the brake information of the digital map on a slope and / or a slope of a preceding section of track is taken into account. Method according to one of the preceding claims, wherein, without the presence of a target point for a desired speed, the predetermined operation of the brake is selected so that only the recuperation function of the brake is used. Method according to one of the preceding claims, wherein the Rekuperationsfunktion has a non-linear efficiency curve, and wherein in the calculation of the predetermined operation of the brake, the efficiency of the Rekuperationsfunktion is taken into account in order to increase the energy recovery. Method according to one of the preceding claims, wherein a recommended distance or time duration for actuating the brake is determined, and wherein the distance or the time duration, in particular the beginning and the end of the braking is communicated to the driver or the driver assistance system. Method according to one of the preceding claims 3 to 9, wherein the destination point at which the vehicle is to have a predetermined speed is communicated to a driver assistance system, in particular an automatic cruise control. Method according to one of the preceding claims, wherein a digital map is provided, wherein between a start and a destination, a route calculation is performed, wherein in the route calculation, a recovery of energy on the recuperation function of the brake is taken into account, with the route calculation, a predetermined energy consumption desired is sought, in particular a minimization of energy consumption or a minimization of energy consumption for a given extended route and / or predetermined extended travel time. Method according to one of the preceding claims, wherein an input sets a desired amount of energy to be obtained via the recuperation function of the brake, the desired amount of energy being used in the route planning and / or determination of the destination point and / or at the determination of the braking distance or the braking time is taken into account. Method according to one of the preceding claims, wherein the predetermined operation is a pressure on the brake pedal and / or a distance of the brake pedal. Method according to one of the preceding claims, wherein at least one parameter of the method via a wireless data connection is received and taken into account in the implementation of the method. Method according to one of the preceding claims, wherein the desired Rekuperationsfunktion is carried out with a high efficiency. A controller adapted to perform a method according to any one of the preceding claims.

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