DE102017204163A1 - Method for operating a motor vehicle with a hybrid drive system and control device for a drive system and a drive system - Google Patents

Abstract

The invention relates to a method for operating a hybrid drive system (2) for a motor vehicle (1), wherein the operation of the drive system (2) is indicated by means of a desired state of charge characteristic of an electrical energy store (7) over a preceding driving distance for providing electrical drive energy in that it comprises the following steps: - providing (S2) a most probable route to be traveled with sections of track, the sections having one or more normal sections and one or more specific sections, determining (S5) the at least one energy demand for entering at least one special section of the route defined by the specific sections of the route (FBB); determination (S7, S8) of an overall desired state of charge progression by the at least one energy requirement being positioned within a maximum state of charge range of the electrical energy store (7) d, so that for each particular route area (FBB) an initial Sollladezustand (SOC start) and a final Sollladezustand (SOCEnde) results, wherein in the at least one normal route sections defined by the normal distance sections (FBN) assumed a linear desired state of charge curve which originates from the final target state of charge (SOCEnde) of at least one of the particular route sections (FBB) and / or ends at the initial target state of charge (SOC start) of at least one of the particular route sections (FBB); - operating the hybrid drive system (2) accordingly the determined total desired state of charge history.

Description

Technical area

The invention relates to motor vehicles with a hybrid drive system, and in particular to operating methods for energy management of hybrid drive systems.

State of the art

In motor vehicles with a hybrid drive system, a drive power in a hybrid mode becomes part of an electric drive and another part of a non-electric drive, such. As an internal combustion engine, provided. The power provided by the individual drive units is determined according to a state of charge characteristic of a state of charge of a drive power required to provide the drive power of the electric drive, the course of which is optimized over a driven driving distance. The state of charge progression indirectly determines, via a hybrid operating strategy, a distribution ratio which indicates the partial drive powers of the individual drive units.

Current optimization methods provide for this purpose to determine the state of charge progression over an underlying driving route in such a way that the total consumption of fuel and / or the total pollutant emissions when driving on the route are minimized. Usually, route information about the route ahead and an additional optimization boundary condition are used for this purpose, e.g. indicates a Endladezustand an electrical energy storage at the end of the route.

The route information results from map data, which can specify other restrictions in addition to the course of the route, such as their length, curvature, gradient or gradient. Such restrictions can u. a. a minimum speed, such as. As on highways, or include information on whether a section is located within an environmental zone in which vehicles must not be driven by internal combustion engine.

Since the conditions of the route and the vehicle condition change regularly, the optimization process is executed again at regular intervals. This represents a significant burden on computational capacities available in motor vehicles.

Disclosure of the invention

According to the invention, a method for operating a motor vehicle with a hybrid drive system according to claim 1 as well as a device and a motor vehicle according to the independent claims are provided.

Further embodiments are specified in the dependent claims.

• - Bereitstellen einer am wahrscheinlichsten zu befahrenden vorausliegenden Fahrstrecke mit Streckenabschnitten, wobei die Streckenabschnitte einen oder mehrere normale Streckenabschnitte und einen oder mehrere besondere Streckenabschnitte aufweisen,
• - Bestimmen des mindestens einen Energiebedarfs zum Befahren von mindestens einem durch die besonderen Streckenabschnitte definierten besonderen Fahrstreckenbereich;
• - Ermitteln eines gesamten Soll-Ladezustandsverlaufs, indem der mindestens eine Energiebedarf innerhalb eines maximalen Ladezustandsbereichs des elektrischen Energiespeichers positioniert wird, so dass sich für jeden besonderen Fahrstreckenbereich ein Anfangs- Sollladezustand und ein End-Sollladezustand ergibt, wobei in dem mindestens einen durch die normalen Streckenabschnitte definierten normalen Fahrstreckenbereich ein linearer Soll-Ladezustandsverlauf angenommen wird, der von dem End-Sollladezustand mindestens eines der besonderen Fahrstreckenbereiche ausgeht und/oder an dem Anfangs-Sollladezustand mindestens eines der besonderen Fahrstreckenbereiche endet;
• - Betreiben des hybriden Antriebssystems entsprechend des ermittelten gesamten Soll-Ladezustandsverlaufs.

According to a first aspect, a method for operating a hybrid drive system for a motor vehicle is provided, wherein the operation of the drive system is indicated on the basis of a desired state of charge curve of an electrical energy store over a preceding driving route for providing electrical drive energy, with the following steps:

• Providing a most likely to be traveled ahead driving route with track sections, wherein the track sections have one or more normal track sections and one or more specific track sections,
• Determining the at least one energy requirement for driving on at least one particular route section defined by the particular route sections;
• Determining an overall desired state of charge curve by positioning the at least one energy demand within a maximum state of charge range of the electrical energy store such that for each particular travel range an initial target state of charge and a final target state of charge results, wherein in the at least one of the normal link sections defined normal route range, a linear desired state of charge curve is assumed, which starts from the final target state of charge of at least one of the particular route sections and / or ends at the initial nominal state of charge of at least one of the particular route sections;
• - Operating the hybrid drive system according to the determined total desired state of charge history.

Thereby, a desired state of charge curve can be provided, which serves as the basis for the operation of the hybrid drive system as a default for the use of electrical energy for a respective forward section. In this case, the desired state of charge is assumed as the target variable of a regulation for an allocation of partial drive powers to the individual drive units, wherein a gradient of the desired state of charge indicates the average energy allocation for the electric drive for a preceding route section.

By the above method, on the one hand, an optimization method to the one ahead Travel route adapted determination of the desired state of charge history are omitted, which is computationally intensive and the available computing capacity in the vehicle heavily loaded. On the other hand, by providing a non-optimized but predetermined, in particular linear desired charge state progression, the optimization target can be approximately achieved. Experiences have shown that in a linear desired state of charge curve, the deviation leads to an optimized set state of charge state over a route to only negligible fuel consumption.

By taking into account the particular route sections for the determination of the predetermined desired state of charge curve, the method is also applicable for route sections whose driving is subject to certain restrictions and therefore they are not readily passable with a predetermined desired state of charge state. For this purpose, it is proposed to adapt the desired state of charge progression of a normal route section in front of at least one of the special route sections, so that sufficient electrical energy is available for driving, in particular for purely electrical driving on the particular route sections. The aim is to use the available electrical energy as evenly as possible over the entire route, as far as this is permissible in view of the restrictions of the special route sections. The estimation of the electrical energy required for driving on the special sections can be made on the basis of map data and the route parameters of the particular sections.

Furthermore, it can be checked whether there is a particular route section within the preceding route, wherein if it is determined that there is no particular route section within the preceding route, the gradient of the linear desired state of charge curve by the length of the route ahead and a difference between a determined Starting charge state, which may correspond to the current state of charge, and a predetermined Endladezustand, which may correspond to a predetermined state of charge at the end of the preceding route, is determined.

Furthermore, the positioning of the at least one energy requirement within a predetermined maximum state of charge range of the electrical energy store can be carried out such that the energy requirement is positioned as a function of a predefined state of charge.

In particular, the positioning of the at least one energy requirement within the maximum state of charge region of the electrical energy store can be carried out so that the energy requirement is positioned symmetrically to a predetermined state of charge or starting from a predetermined state of charge.

Furthermore, the predetermined state of charge may decrease with decreasing distance to a destination of the route ahead. So if the special route is more at the beginning of the total distance and the starting charge state is high, the energy requirement can be positioned in the upper range of the maximum charge state range. In the opposite case, if the special route is closer to the end of the total route, one can position the energy requirement in the lower part of the maximum charge state range.

It can be provided that the predefined state of charge is selected as a function of the length of the particular route, a quality of the energy consumption estimate and / or an overall efficiency of the entire drive train.

It can be provided that the at least one particular route section corresponds to an environmental zone in which the hybrid drive system is to be operated purely electrically.

• - eine am wahrscheinlichsten zu befahrende vorausliegende Fahrstrecke mit Streckenabschnitten bereitzustellen, wobei die Streckenabschnitte einen oder mehrere normale Streckenabschnitte und einen oder mehrere besondere Streckenabschnitte aufweisen,
• - den mindestens einen Energiebedarf zum Befahren von mindestens einem durch die besonderen Streckenabschnitte definierten besonderen Fahrstreckenbereich zu ermitteln;
• - einen gesamten Soll-Ladezustandsverlauf zu ermitteln, indem der mindestens eine Energiebedarf innerhalb eines maximalen Ladezustandsbereichs des elektrischen Energiespeichers positioniert wird, so dass sich für jeden besonderen Fahrstreckenbereich ein Anfangs-Sollladezustand und ein End-Sollladezustand ergibt, wobei in dem mindestens einen durch die normalen Streckenabschnitte definierten normalen Fahrstreckenbereich ein linearer Soll-Ladezustandsverlauf angenommen wird, der von dem End-Sollladezustand mindestens eines der besonderen Fahrstreckenbereiche ausgeht und/oder an dem Anfangs-Sollladezustand mindestens eines der besonderen Fahrstreckenbereiche endet;
• - das hybride Antriebssystem entsprechend des ermittelten gesamten Soll-Ladezustandsverlaufs zu betreiben.

According to a further aspect, an apparatus for operating a hybrid drive system for a motor vehicle is provided, wherein the operation of the drive system is indicated on the basis of a desired state of charge curve of an electrical energy store over a preceding route for providing electrical drive energy, wherein the device is designed to:

• to provide a most likely to-be-ahead route with sections of track, the sections having one or more normal sections and one or more particular sections,
• to determine the at least one energy requirement for driving on at least one particular route section defined by the particular route sections;
• to determine an overall desired state of charge curve by positioning the at least one energy demand within a maximum state of charge area of the electrical energy store such that there is an initial nominal state of charge and a final nominal state of charge for each particular travel area, wherein at least one of the normal Sections defined normal distance covered by a linear setpoint Charge state course is assumed, which emanates from the End-Sollladezustand at least one of the particular route sections and / or ends at the initial target state of charge of at least one of the particular route sections;
• - To operate the hybrid drive system according to the determined total desired state of charge history.

list of figures

• 1 eine schematische Darstellung eines Kraftfahrzeugs mit einem hybriden Antriebssystem;
• 2 ein Flussdiagramm zur Veranschaulichung des Verfahrens zum Betreiben des hybriden Antriebssystems durch Vorgabe des Ladezustandsverlaufs des elektrischen Energiespeichers über die vorausliegende Fahrstrecke; und
• 3a und 3b Verläufe der Geschwindigkeit und des Ladezustands über eine vorausliegende Fahrstrecke mit einem besonderen Fahrstreckenbereich; und
• 4a und 4b Verläufe der Geschwindigkeit und des Ladezustands über eine vorausliegende Fahrstrecke mit zwei besonderen Fahrstreckenbereichen.

Embodiments are explained below with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a motor vehicle with a hybrid drive system;
• 2 a flowchart illustrating the method for operating the hybrid drive system by specifying the state of charge history of the electric energy storage over the preceding route; and
• 3a and 3b Traces of the speed and the state of charge over a route lying ahead with a special route section; and
• 4a and 4b Progression of the speed and the state of charge over a preceding route with two special route sections.

Description of embodiments

1 shows a motor vehicle 1 with a hybrid drive system 2 that is a first drive unit 3 , For example, an internal combustion engine, and a second drive unit 4 , For example, an electric drive has. The first drive unit 3 and the second drive unit 4 can jointly or separately provide a drive torque (eg, purely internal combustion engine or purely electric), ie, a drive power, via a (not shown) output shaft to drive wheels.

The internal combustion engine as the first drive unit 3 is using fuel as a chemical fuel via a fuel tank 6 provided. The electric drive as the second drive unit 4 is supplied with electrical energy from an electrical energy storage 7, in particular from a rechargeable battery.

The hybrid drive system 2 further comprises a hybrid control device 5 to the first drive unit 3 and the second drive unit 4 to drive to provide a respective partial drive torque.

It is a vehicle control unit 10 provided that the hybrid control unit 5 an information about the drive torque to be provided; as well as information about a load distribution. The load distribution is at a total drive power to be provided or the drive torque to be provided a division of the different drive units 3 . 4 to be provided partial drive powers or partial drive torques. The total drive power to be provided or the drive torque to be provided can be, for example, as a manipulated variable from a speed control 11 result, which may be implemented in the control unit 10 or separately thereto, or by a driver's default, for example via a position of the accelerator pedal, which dictates a driver's desired torque.

The speed control 11 serves this purpose by providing a manipulated variable to the hybrid control unit 5 to regulate the speed of the motor vehicle to a desired vehicle speed. The speed control 11 can be configured to be dependent on a deviation of the vehicle speed to the target vehicle speed as a manipulated variable an indication of the drive torque to be provided to the hybrid control unit 5 to deliver.

The vehicle control unit 10 can with a route information system 12 that may be included in a navigation system. The route information system 12 may be part of a driver assistance system or part of a navigation system. The route information system 12 accesses a local or external map store which can provide information about links.

The route information system 12 can provide information about the route ahead. The route information system 12 determined based on eg provided by the driver navigation data or the like a route that is most likely driven by the vehicle (most likely route). Furthermore, the most probable route can also be determined in a manner known per se from historical driving data on previously traveled routes.

The route ahead is determined by one or more connected sections. The route information system 12 can the vehicle control unit 10 provide the route section information in addition to information about the course of the route sections. The route section information comprises energy-relevant parameters for each of the relevant route sections, in particular average speeds, Speed limits, for example, resulting from legal speed specifications, straightening speeds, gradients and gradients and / or curve radii, or the like.

The vehicle control unit 10 is formed, a desired state of charge history of the electrical energy storage 7 to specify the route ahead. In particular, the route ahead is subdivided into normal route sections and special route sections. The particular route sections differ from the normal route sections in that the predetermined target state of charge state changes by a prescribed mode depending on the route section information, while in the normal route sections, the target state of charge history is set independently of the link information. For example, the particular driving route area may correspond to an environmental zone in which the motor vehicle may only be operated electrically.

In conjunction with the flowchart of 2 A method for operating a motor vehicle with a hybrid drive system is described in the vehicle control unit 10 can be carried out.

In order to be able to realize the propulsion of the motor vehicle exclusively in the particular driving route areas electrically, a trajectory planning for the state of charge progression must be carried out. A method for operating the hybrid drive system therefore includes determining a desired state of charge curve for the route ahead. The desired state of charge curve indicates, for incremental sections, the electrical energy to be provided for the operation of the electric drive. The distribution of the electrical energy over this incremental section takes place in accordance with an operating strategy that determines operating points of the hybrid drive system such that at the end of the incremental section the predetermined state of charge predefined by the desired state of charge is reached.

For this purpose, the current state of charge of the electrical energy store 7 is determined as the starting charge state SOC _start in step S1.

In step S2, a preceding route is determined as the most likely traveled route.

In step S3, the contiguous route sections defining the preceding travel route are determined from the map data and the route sections using the route information system 12 Assigned route section information. The route section information includes information about the type of the route, the average speed at which the motor vehicle drives the route section concerned, the curvature, inclines and inclines, and the like. Furthermore, a final charging state SOC _{conclusion is} given for the end of the preceding route, which usually a nearly discharged electrical energy storage 7 equivalent.

Furthermore, route parameters for each of the links can also indicate whether the link in question is a particular link, e.g. a section of track that may only be driven electrically, for example to define an environmental zone. A particular route area, such as the environmental zone, represents an area of one or more connected sections, in which the motor vehicle may only be driven electrically. This means that route positions are available on the route ahead that indicate the start and end positions of a particular route section. The route may include one or more environmental zones.

vorgegeben, wobei s_ges der gesamten Strecke der vorausliegenden Fahrstrecke entspricht. Anschließend wird zu Schritt S1 zurückgesprungen.In step S4, it is checked whether there is a particular driving route area within the preceding driving route. If this is the case (alternative: yes), the method is continued with step S5. Otherwise (alternative: no), in step S6, the state of charge curve as a linear state of charge curve with a path-dependent gradient of $$\frac{\left({\text{SOC}}_{Start}-{\text{SOC}}_{ScHluss}\right)}{s_{Ges}}$$

predetermined, where s _tot corresponds to the entire route of the route ahead. Subsequently, it returns to step S1.

In step S5, for each of the particular travel route areas, the energy demand of electric power is estimated depending on the route section information of the route sections that make up the particular travel route area. This is done in a conventional manner, since due to the average speeds, the increases and drops of the sections of the power requirement for the drive of the motor vehicle 1 can be determined, so that this results in an energy requirement for a purely electric drive of the motor vehicle within the particular special route range. Alternatively, the energy requirement can also be empirically derived from previous passages of the route range. From the energy requirements for each of special travel route areas result in conjunction with the total capacity of the electrical energy storage state of charge requirements ΔSOC _{demand 1} ... ΔSOC _{demand n} for the special driving distance ranges F1 ... Fn.

In step S7, the respective state of charge _demand ΔSOC _{demand 1} ... ΔSOC _{demand n is arranged} within a maximum state of charge range between a maximum state of charge SOC _max and a minimum state of charge SOC _min for each of the travel distance regions. The arrangement can be essentially arbitrary. In particular, the arrangement is based on a predetermined state of charge SOC _ref , which has previously been determined, for example, as a state of charge for the electrical energy store, in which this can be operated with high or highest possible efficiency or according to another optimization target predetermined optimum. For example, this predetermined state of charge SOC can be between 60% and 70%. The state of charge requirements ΔSOC _{demand 1} ... ΔSOC _{demand n} can now be arranged symmetrically about the predefined state of charge so that an initial charge state SOC _start and a final charge state SOC _end result for each particular travel route region. If this is not possible, since a predetermined limitation of the maximum state of charge SOC _max or the minimum state of charge SOC _min , which define the maximum state of charge range, would be exceeded, or alternatively the state of charge _demand ΔSOC _{demand 1} ... ΔSOC _{demand n} with its initial state of charge SOC _beginning or its final charge state SOC _end to the maximum state of charge SOC _max or the minimum state of charge SOC _{min be} moved.

Furthermore, the predetermined state of charge can be predetermined as a function of distance, so that this decreases as the distance to the destination decreases. Thus, if the particular driving route area is at the beginning of the entire driving route and the starting charge state is high, the energy requirement can rather be positioned in the upper region of the maximum charge state area. In the opposite case, if the particular route section is closer to the end of the total route, it is more likely to position the energy requirement in the lower part of the maximum state of charge.

It is also possible to make a positioning of the state of charge region as well as an adjustment of the size of the energy requirement dependent on further factors: e.g. the length of the particular route, in particular with regard to the entire drive cycle, quality of energy estimation, distance to start and end position, overall efficiency of the entire powertrain.

According to a further embodiment, state of charge requirements ΔSOC _{demand 1} ... ΔSOC _{demand n} for the particular travel ranges F1... Fn can be positioned in the range between the starting charge state SOC _start and the predetermined discharge state SOC _end for each of the particular travel route regions. The positioning of the state of charge requirements ΔSOC _{demand 1} ... ΔSOC _{demand n} over the entire state of charge between SOC _start and SOC _end can furthermore take place in such a way that the state of charge becomes as linear as possible during the driving of the normal route sections between the particular route sections Gradients of decreases in the desired state of charge for the normal route sections may be identical.

In step S8, the target state of charge curve for the normal driving distance ranges by linear gradients between the starting state of charge SOC _start and the initial state of charge SOC _beginning of the first specific travel distance range FBB, between the Endladezuständen SOC _end of each of the specific route areas FBB and an initial state of charge SOC _beginning of the next special travel distance range and the final charge state SOC _{end of} the last specific travel route area FBB and the final charge state SOC _termination .

Thereafter, the process returns to step S1, and the process is repeatedly performed.

The 3a and 3b show a speed curve and a desired state of charge curve over a route lying ahead with a particular route section FBB between two normal route sections FBN and a predefined for driving the particular route range state of charge _demand ΔSOC _demand . One recognizes in the 3b a linear decrease of the desired state of charge in the lying outside of the particular route range normal driving route areas, so that at the end of the route of Endladezustand SOC _end can be achieved.

The positioning of the range of the state of charge _demand ΔSOC _{requirement of} the particular route section is symmetrical about the predetermined state of charge SOC _ref as described above. This results in the initial state of charge SOC _start and the _{end state} of charge SOC _end for the particular route area concerned.

In the case of several special route sections, a desired state of charge status may result as shown in FIG 4a and 4b is shown. Unlike the case of 3a and 3b here increases the desired state of charge history before and after the special route sections FBB.

Deviating from the purely linear course of the desired state of charge between the starting charge state and the final charge state due to the particular travel route regions resulting deviating desired state of charge state can be provided in each case as a difference-desired state of charge history. That From the result of the desired state of charge curve obtained in step S8, the purely linear curve that would result without the particular route sections can be subtracted. The difference-desired state of charge curve can then be taken into account for the consideration of the influence of special route sections also changed strategies for the determination of desired state of charge progressions by simple addition.

Claims (12)

Method for operating a hybrid drive system (2) for a motor vehicle (1), wherein the operation of the drive system (2) is indicated by means of a desired state of charge curve of an electrical energy store (7) over a preceding route for providing electrical drive energy, with the following steps : Providing (S2) a most likely to be traveled ahead driving route with track sections, wherein the track sections have one or more normal track sections and one or more specific track sections, - determining (S5) the at least one energy requirement for driving on at least one particular travel route area (FBB) defined by the particular route sections; - Determining (S7, S8) of a total desired state of charge history by the at least one energy requirement within a maximum state of charge of the electrical energy storage device (7) is positioned so that for each particular route range (FBB) an initial Sollladezustand (SOC start) and End Sollladezustand (SOCEnde) results, wherein in the at least one normal route sections defined by the normal route sections a linear desired state of charge curve is assumed, which starts from the End Sollladezustand (SOCEnde) at least one of the special route sections (FBB) and / or at the initial nominal state of charge (SOC start) of at least one of the special route sections (FBB) ends; - Operating the hybrid drive system (2) according to the determined total desired state of charge history. Method according to Claim 1 wherein it is checked whether a particular route section (FBB) is located within the preceding route, wherein if it is determined that there is no particular route section (FBB) within the preceding route, the gradient of the nominal linear state of charge curve is determined by the length of the preceding route and a difference between a determined starting state of charge (SOC _start ) at the current vehicle position and a predetermined final state of charge (SOC _end ) is determined at the end of the preceding route. Method according to Claim 1 or 2 wherein the positioning of the at least one energy demand within the maximum state of charge range of the electrical energy store (7) is performed so that the energy requirement is positioned depending on a predetermined state of charge. Method according to Claim 3 wherein the positioning of the at least one energy demand within the maximum state of charge range of the electrical energy store (7) is performed so that the energy demand is positioned symmetrically to a predetermined state of charge (SOC _ref ) or from the predetermined state of charge. Method according to Claim 3 or 4 wherein the predetermined state of charge (SOC _ref ) decreases with decreasing distance to a destination of the preceding route. Method according to one of Claims 3 to 5 wherein the predetermined state of charge (SOC _ref ) is selected depending on the length of the particular route, a quality of the energy consumption estimate and / or an overall efficiency of the entire drive train. Method according to one of Claims 1 to 6 , wherein the at least one particular route section corresponds to an environmental zone in which the hybrid drive system (2) is to be operated purely electrically. Method according to one of Claims 1 to 7 In the case of a positive gradient of the linear desired state of charge progression in a normal route section, an energy input into the electrical energy store (7) is carried out by a load point increase of the non-electrically operated drive unit (3). Device for operating a hybrid drive system (2) for a motor vehicle (1), wherein the operation of the drive system (2) based on a desired state of charge curve of an electric Energy storage device (7) is provided over a preceding route for providing electrical drive energy, the device being designed to: - provide a most likely to be traveled ahead driving route sections, the route sections one or more normal sections and one or more special sections have, - to determine the at least one energy requirement for driving on at least one particular route section (FBB) defined by the particular route sections; determining an overall desired state of charge curve by positioning the at least one energy requirement within a maximum state of charge area of the electrical energy store so that an initial nominal state of charge (SOC start) and an end nominal state of charge for each particular travel area FBB SOCEnde), wherein in the at least one defined by the normal route sections normal driving route area (FBN) a linear desired state of charge curve is assumed by the End Sollladezustand (SOCEnde) of at least one of the special route sections (FBB) and / or Initial set state of charge (SOC start) of at least one of the particular travel route areas (FBB) ends; - To operate the hybrid drive system (2) according to the determined total desired state of charge history. Hybrid drive system (2) for a motor vehicle (1), comprising a plurality of drive units and a device according to Claim 9 , Computer program adapted to perform all steps of a method according to one of Claims 1 to 8th perform. Machine-readable storage medium on which a computer program is based Claim 11 is stored.

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