DE102017211137A1 - Method for determining a degree of recuperation and for carrying out recuperation according to the recuperation degree - Google Patents

Abstract

The present invention relates to a method for recuperating kinetic energy of a vehicle, in which at least one degree of recuperation for at least one deceleration distance is already determined in advance and is applied during a driving of the at least one deceleration distance for deceleration of the vehicle as part of a recuperation process.

Description

The present invention relates to a method for recuperating kinetic energy of a vehicle, in which at least one degree of recuperation for at least one deceleration distance is already determined in advance and is applied during a driving of the at least one deceleration distance for deceleration of the vehicle as part of a recuperation process.

Vehicles with an electric main drive or auxiliary drive can at least partially convert into useful energy during braking processes, the kinetic energy of the vehicle. This energy recovery or recuperation usually takes place in several stages. In a first stage or a first degree of recuperation, a defined part of the thrust output of the vehicle is recuperated. This can be done for example in a rolling out of the vehicle. At a higher degree of recuperation a brake pedal operation is detected, so that a higher braking effect is obtained by the recuperation with a higher recuperation. If a braking effect which is necessary for this higher degree of recuperation is required, this difference is generated by the mechanical brake of the vehicle.

From the DE102013209837A1 a recuperation arrangement for a vehicle is known. A control unit of the recuperation arrangement serves to distribute the generated recuperation energy in at least two storage units.

The DE102013217897A1 describes a method for regenerating an electrical energy storage. By means of the method, an energy storage subject to aging effects can be used optimally.

The DE102013009277A1 discloses a method and apparatus for operating a vehicle. From a route profile sections are determined with a slope and used to perform a Rekuperationsverfahrens.

The problem with the previous recuperation methods are the coarse and situation-independent recuperation rates, by means of which only part of a braking power required on a deceleration path can be recovered as useful energy.

The invention is therefore based on the object to propose an optimized method for braking a vehicle with improved utilization of the braking energy.

An object of the present invention is a method for Rekuperieren kinetic energy of a vehicle, wherein based on a future route profile at least one future delay line and for the at least one delay line a necessary delay power are determined. Based on the at least one delay line and the corresponding delay power, at least one degree of recuperation is calculated.

During driving on the at least one deceleration path of the route profile, a recuperation process is carried out by the vehicle in accordance with the at least one calculated recuperation degree. Subsequently, the vehicle is decelerated while driving on the at least one deceleration path through the recuperation process. Within the scope of the present disclosure, a degree of recuperation is to be understood as meaning a portion of the kinetic energy (translatory kinetic energy) available in a moving vehicle and the potential energy (positional energy) that can be converted into recuperation energy or used as part of a recuperation process or Recuperation process can be used again or fed back. This means that a portion of the translatory kinetic energy and positional energy is consumed by air resistance, rolling resistance and / or driveline losses, while the remaining proportion, ie. H. the Rekuperationsgrad, can be made available for use a Rekuperationsvorgang. For this purpose, for example, electric drives in a generator mode can convert the proportion of kinetic energy and potential energy defining the degree of recuperation into electrical energy and achieve a braking effect.

With the aid of predictive route data, it is possible to "look ahead" during operation of the vehicle or to ascertain which delay services are likely to be necessary in the respective delay sections. A deceleration path may be a path for decelerating the vehicle to the stall or adjusting a speed of the vehicle to a speed limit. The delay route can be adapted, for example, to the highest possible comfort or to a sporty driving style. The necessary deceleration services may, for example, be retrievable from speed limits, intersections, traffic lights or stop signs on the current or future route of the vehicle. In a predefined route profile, such as a navigation route, the delay lines within the route can be determined and the respective ones for this necessary delay services are calculated. It can thus be determined with a corresponding recuperation or braking power adapted to the respective braking situation or delay line Rekuperationsgrad. The recuperation rate is calculated as a function of the given boundary conditions. If the driver reverses a deceleration request, for example, by taking a foot of the driver from an accelerator pedal of the vehicle or the brake pedal is pressed, a brake manager can be activated, which applies the adapted according to the inventive Rekuperationsverfahren and decelerates the vehicle as planned. In this case, based on a vehicle position, it can be determined, for example, which deceleration distance is currently approached by the vehicle and the recuperation method with a recuperation degree corresponding to the distance traveled is used to decelerate the vehicle. An additional braking request of the driver exceeding the recuperation degree ascertained in advance can be made available by a situation-dependent increase in the degree of recuperation and / or by the mechanical brake. As a result, the deceleration power required along a route can be optimally utilized in the form of recuperation energy.

According to one embodiment of the invention, based on the at least one delay path and the corresponding delay power, at least one maximum degree of recuperation is calculated and applied in at least one recuperation process. As a result, each braking process can be maximally utilized along a route and an efficiency of the respective recuperation processes or recuperation processes can be increased. Since the mechanical brake is less or not needed, wear of the mechanical brake can be reduced.

According to a further embodiment of the invention, in at least one recuperation process, the kinetic energy of the vehicle is converted into useful energy. The delay power may be used to generate recuperation electrical energy or to generate mechanical or thermal energy. A conversion into thermal energy is possible for example by resistances. For example, electrical recuperation energy generated by braking resistors can be converted into thermal energy. The thermal energy can be used, for example, for heating drive components or for heating a vehicle interior. The mechanical energy can be used for example via a flywheel to drive fans or the air conditioning.

According to a further embodiment, the converted useful energy is stored directly or indirectly in at least one energy store. The electrical recuperation energy can be stored for example in electrochemical storage or in capacitors for later use. As possible electrochemical storage, lithium ion, lithium polymer, nickel cadmium storage batteries and the like can be used. The stored electrical energy can then be used to drive at least one electric motor. Alternatively or additionally, it is also possible to use thermal stores and / or mechanical stores, such as flywheels, for the temporary direct or indirect storage of the generated recuperation energy. Thereby, the recuperation energy generated from the deceleration energy can be used to support other components of the vehicle, such as air conditioning, power generation, and the like.

According to a further embodiment, the at least one deceleration power is determined based on the at least one corresponding deceleration distance, a total vehicle mass, and at least one vehicle speed. For this purpose, an algorithm can calculate from the current position of the vehicle, a current speed of the vehicle and the future possible speed default point and the knowledge from the existing moving mass, which maximum recuperation energy content would be present in the present route section and from when a braking process would usefully be initiated. For example, a maximum deceleration power may be calculated from a product of total vehicle mass, deceleration acceleration, and vehicle speed. The maximum delay power can then be passed on to the various energy storage and energy conversion systems. As a result, an accurate prediction of the necessary deceleration performance can be made.

According to a further embodiment, the total vehicle mass is determined on the basis of a stored vehicle idle mass and a seat occupancy recognition. In this case, for example, various present initial variables of the vehicle can be retrieved from a control unit. For example, the data necessary for this purpose can be stored in a CAN bus ready for call. Seat occupancy recognition can be used to determine how many people are present in the vehicle so that the total vehicle mass can be determined precisely. For example, a passenger weight of, for example, 75 kg per passenger can be assumed, so that No additional components are needed to determine the weight.

According to a further embodiment, the vehicle mass is determined taking into account trailer operation. In this case, for example, based on an electrical contacting of the trailer a trailer operation can be registered. As a result, the total vehicle mass can be adjusted or corrected depending on the situation.

According to a further embodiment, the total vehicle mass is determined based on at least one acceleration process of the vehicle. The vehicle stores during normal operation with the aid of predictive track data from various acceleration processes, such as from a standstill to a defined speed, the required acceleration power or a consumed energy content of the drive or the drive units. This power or energy content results in a base value for a calculation of the total vehicle mass relative to the mean acceleration. Here, the total vehicle mass can be determined in a trailer operation taking into account the trailer weight. Here, the average acceleration and the required power for the acceleration process are in a fixed ratio. The power for the acceleration process results from a product of the total vehicle mass, the acceleration and the final speed of the acceleration process. This determined and stored base value for the performance of this vehicle is then compared with the acceleration performance / energies in trailer operation. The total vehicle mass is calculated as the sum of the vehicle mass and the trailer mass. In addition, even with knowledge of the acceleration performance, such as from internal drive data, such as the drive power, estimate how large the actual vehicle mass of the towing vehicle is in a trailer operation, unless this information is available from networking data. In particular, acceleration data up to a speed of 50 km / h can be used. At speeds below 50 km / h, the acceleration performance over aerodynamic drag and rolling resistance performance of the vehicle outweighs the drive power at the wheels. Thus, in this rough consideration aerodynamic performance and rolling resistance performance can be neglected and a computational effort can be reduced.

According to a further embodiment, the at least one vehicle speed is determined from the route profile. The vehicle recognizes the current driving speed and position from predictive data or network data. In addition, the vehicle may determine the likely future vehicle speeds from previously traversed slots and / or stored speed limits within a navigation route. As a result, the estimated vehicle speeds can be technically easily removed from databases.

According to a further embodiment, the at least one vehicle speed is measured before determining the at least one degree of recuperation. In this case, the current speed of the vehicle can be removed from a control unit of the vehicle at a defined distance to a next deceleration distance. Alternatively, a current speed of the vehicle can be determined via a GPS signal. Thus, just prior to performing the recuperation process current and accurate boundary conditions can be determined, so that the optimal mechanical brake does not need to be operated.

The invention is illustrated schematically with reference to an embodiment in the drawing and will be further described with reference to the drawing.

• 1 shows a schematic representation of an embodiment of a method according to the invention.

The 1 shows a schematic flowchart of a method 1 for recuperation of kinetic energy of a vehicle according to an embodiment of the invention. In one step 2 a route profile or a future route of the vehicle is determined. From the route profile will be in one step 3 Delay distances determined. The delay lines here are sections of track at which the vehicle must adjust its speed or be braked to a stand. The respective delay lines are in a further step 4 respective delay performance determined. Based on the respective delay performances are in one step 5 calculated recuperation for each delay line. During a driving on the route profile and in particular during driving on the respective delay lines is the vehicle in one step 6 in each case one recuperation process or recuperation process is carried out in accordance with the calculated recuperation rates. In this case, the vehicle can optimally be adjusted without the use of a mechanical brake wear-free in its speed and at least electrical Rekuperationsenergie be generated from the kinetic energy of the vehicle.

LIST OF REFERENCE NUMBERS

1

method

2

Determine a future route

3

Determining Delay Lines

4

Determining Delay Services

5

Calculate recuperation levels

6

Carrying out recuperation procedures

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 102013209837 A1 [0003]
• DE 102013217897 A1 [0004]
• DE 102013009277 A1 [0005]

Claims (10)

Method (1) for recuperation of kinetic energy of a vehicle, wherein on the basis of a future route profile (2), at least one future delay route (3) and for the at least one delay route a necessary deceleration power (4) are determined, at least one degree of recuperation (5) is calculated based on the at least one delay path and the corresponding delay power, - During a driving of the at least one deceleration distance of the route profile of the vehicle performs a recuperation process (6) corresponding to the at least one calculated Rekuperationsgrad and the vehicle is delayed by the Rekuperationsvorgang. Method according to Claim 1 in which, based on the at least one delay line (3) and the corresponding delay power (4), at least one maximum recuperation degree (5) is calculated and applied in at least one recuperation method (6). Method according to Claim 1 or 2 In at least one recuperation method (6), the kinetic energy of the vehicle is converted into useful energy. Method according to Claim 3 , wherein the converted useful energy is stored directly or indirectly in at least one energy store. Method according to one of Claims 1 to 4 wherein the at least one deceleration power (4) is determined based on the at least one corresponding deceleration distance (3), a total vehicle mass and at least one vehicle speed. Method according to Claim 5 , wherein the total vehicle mass is determined based on a stored vehicle idle mass and a seat occupancy detection. Method according to Claim 5 or 6 , Wherein the total vehicle mass is determined in consideration of a trailer operation. Method according to one of Claims 5 to 7 wherein the total vehicle mass is determined based on at least one acceleration process of the vehicle. Method according to one of Claims 5 to 8th wherein the at least one vehicle speed is determined from the route profile. Method according to one of Claims 5 to 9 wherein the at least one vehicle speed is measured prior to determining the at least one degree of recuperation.

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