DE102015209883A1 - Method and device for operating a hybrid vehicle - Google Patents

Abstract

The invention relates to a method for operating a hybrid drive system with a plurality of drive units (3, 4) in a motor vehicle (1) with the following cyclically executed steps: - Transmission (S2) of a position information about a current position of the motor vehicle (1) to an external from the motor vehicle arranged central unit (20); - in response to the transmission of the position information; Receiving (S3) an indication of a load distribution, which indicates a distribution of the services to be provided by the drive units (3, 4); - Operating (S4) of the drive units (3, 4) according to the indication of the load distribution.

Description

Technical area

The invention relates to methods for operating a hybrid drive system in a motor vehicle, and more particularly to methods for providing an optimal operating strategy

State of the art

Hybrid drive systems are often provided with various drive units, such as an internal combustion engine or an electric motor, which together provide drive power to the motor vehicle. According to a hybrid operating strategy, the fuel consumption of the internal combustion engine can be reduced or minimized by targeted support by the electric motor with electrical energy from a high-voltage battery. Depending on the type of hybridization, i. the dimensioning of the components of the electric powertrain, a distinction is made between micro-HEVs (HEV: Hybrid Electric Vehicle), Mild HEVs, Full / Strong HEVs and plug-in HEVs.

For the application of the hybrid operating strategy, in particular the full / strong HEVs and plug-in HEVs are of interest because, on the one hand, they contain significant portions of the route purely electrically, i. covered with disconnected or switched off internal combustion engine and on the other hand can provide a significant shift of the load point of the internal combustion engine in its support. As a result, a significant increase in the efficiency of the internal combustion engine and thus a significant reduction in fuel consumption can be achieved.

In general, the electric drive in conjunction with the corresponding battery thus provides a degree of freedom in all hybrid operating strategies to reduce fuel consumption. In particular, if the hybrid operating strategy takes into account the topography of the route ahead, this degree of freedom can be usefully used to reduce fuel consumption.

Disclosure of the invention

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

• – Übermitteln einer Positionsangabe über eine aktuelle Position des Kraftfahrzeugs an eine extern vom Kraftfahrzeug angeordnete Zentraleinheit;
• – als Antwort auf die Übermittlung der Positionsangabe, Empfangen einer Angabe über eine Lastverteilung, die eine Aufteilung der von den Antriebseinheiten bereitzustellenden Leistungen angibt; und
• – Betreiben der Antriebseinheiten gemäß der Angabe über die Lastverteilung.

Further embodiments are specified in the dependent claims. According to a first aspect, a method for operating a hybrid drive system with a plurality of drive units in a motor vehicle is provided, with the following cyclically executed steps:

• Transmitting a position information about a current position of the motor vehicle to a central unit arranged externally of the motor vehicle;
• In response to the transmission of the position indication, receiving an indication via a load distribution which indicates a distribution of the services to be provided by the drive units; and
• - Operating the drive units as specified by the load distribution.

• – Empfangen einer Positionsangabe über eine aktuelle Position eines von der Zentraleinheit separaten Kraftfahrzeugs;
• – Ermitteln einer Angabe über eine optimierte Lastverteilung für Antriebseinheiten eines Hybridantriebssystems des Kraftfahrzeugs abhängig von der empfangenen Positionsangabe, wobei die Lastverteilung eine Aufteilung der von den Antriebseinheiten bereitzustellenden Leistungen angibt;
• – Übermitteln der Angabe über die optimierte Lastverteilung an das Kraftfahrzeug.

According to a further aspect, a method for operating a central unit is provided, with the following cyclically executed steps:

• - Receiving a position information on a current position of a separate from the central unit motor vehicle;
• - Determining an indication of an optimized load distribution for drive units of a hybrid drive system of the motor vehicle depending on the received position information, wherein the load distribution indicates a distribution of the services to be provided by the drive units;
• - Transmission of the information about the optimized load distribution to the motor vehicle.

From the prior art, a variety of approaches to the design of hybrid operating strategies for hybrid drive systems in motor vehicles are known. For example, an ECMS (Equivalent Consumption Minimization Strategy) provides for the load distribution between different drive units to be selected for a section of track to be traveled in such a way that the total energy costs over a considered route are minimal. The total energy consumption results from a cost function corresponding to the sum of the weighted energy consumptions of the various types of energy, for example, a fuel energy as the chemical energy of the fuel or an electric energy in a rechargeable traction battery. At any point in time, therefore, the load distribution of the power of the internal combustion engine and the power of the electric drive is selected so that the weighted sum of the supplied fuel power and the supplied weighted electrical power is minimal.

The ECMS method is able to achieve a nearly globally optimal solution, ie a minimum fuel consumption for the entire driving distance of the motor vehicle. For this purpose, only the weighting factor of the cost function has to be adjusted in a suitable manner. One known way of determining the weighting factor (also called equivalence factor) is to calculate it based on a deviation between a current one To determine the state of charge of an electrical energy storage of a planned target state of charge and to adjust the weighting factor so that the current state of charge the nominal state of charge follows in a satisfactory approximation. This allows the optimization problem to be mapped to the planning of the optimum desired state of charge of the electrical energy store instead of the search for the correct weighting factor.

The course of the desired state of charge or any other information about the load distribution can be determined predictively taking into account a route lying ahead. This requires knowledge of the route profile of the route ahead. However, in the motor vehicle, it requires a large memory overhead for storing route information, such as in a digital road map with a height profile and the like. In addition, it is laborious to regularly update such a digital road map with a corresponding elevation profile in each motor vehicle, and rapidly changing road conditions, such as in structural changes and construction sites, traffic and the like can not be considered in their most recent form.

It is therefore provided with the above method, regularly provide a respective current information on a load distribution for drive units in a hybrid drive system in a motor vehicle position-dependent from external. For this purpose, the motor vehicle transmits a respective position information to a central system and in response receives an information about the load distribution to be set in the central system based on the digital road map present therein with the route information contained therein.

In the motor vehicle, the received information about the load distribution is now converted accordingly. The transmission of the position information by the hybrid drive system and the receipt of the corresponding information about the load distribution are cyclic, so that the motor vehicle can always be operated while driving on the route ahead in accordance with an externally optimized load distribution. This has the advantage that the otherwise complex calculation of the load distribution based on a predictive forecast of route parameters of a preceding route can not be made in the hybrid drive system, but externally in a central processing unit.

The continuous transmission of the respectively optimized indication of the load distribution to the hybrid drive system from the outside makes it possible on the one hand to operate the hybrid drive system with a fuel saving. On the other hand, it is only necessary to determine the current vehicle position in the motor vehicle and to transmit this to the central unit without having to keep in the motor vehicle an always current virtual road map with altitude profile and other route information that can affect fuel consumption. As a result, an interface between a navigation system in which a digital road map could be stored and a control unit for the hybrid drive system can be omitted.

Furthermore, the drive units may comprise an electric drive, which is connected to an electrical energy store for supplying the electric drive with electrical energy, wherein the indication of the load distribution comprises a desired state of charge, wherein the electric drive is operated with a power, so that an actual state of charge of the electrical energy storage is set in the direction of the desired state of charge or the state of charge is regulated to the desired state of charge.

The information about the load distribution to be set can thus be transmitted in the form of a desired state of charge for the traction battery to the motor vehicle or be received by the latter. Depending on the information given about the load distribution, the drive system can now be operated in a corresponding manner with a load distribution between the drive units in accordance with the information received about the load distribution.

By choosing the desired state of charge of the electrical energy storage as an indication of the load distribution that is transmitted, any operating strategy can be provided in the central unit. In addition, the digital road map can be provided in a simple manner updated once in the central unit and thus also short-term changes on routes that can affect fuel consumption, are taken into account.

Furthermore, in the method for operating a central unit, the information about the optimized load distribution can be determined as a function of route parameters of a route lying ahead.

According to one embodiment, in the method for operating a central processing unit, the information about the load distribution can be determined by determining a velocity trajectory along an electronic route horizon and optimizing the course of the load distribution along the velocity trajectory.

In particular, in the method for operating a central processing unit, the electronic route horizon may be determined as a most likely traveled route or a portion thereof.

It can be provided in the method for operating a central unit that is determined as an indication of the load distribution, a desired state of charge of an electrical energy storage of the hybrid drive system and transmitted.

• – eine Steuereinheit zum Betreiben der Antriebseinheiten gemäß einer Angabe über eine Lastverteilung, wobei die Lastverteilung eine Aufteilung der von Antriebseinheiten des Hybridantriebssystems bereitzustellenden Leistungen angibt; und
• – eine Sende-/Empfangseinrichtung zum Übermitteln einer Positionsangabe über eine aktuelle Position des Kraftfahrzeugs nach extern, insbesondere an eine extern vom Kraftfahrzeug angeordnete Zentraleinheit, und zum Empfangen einer Angabe über eine Lastverteilung als Antwort auf die Übermittlung der Positionsangabe.

In another aspect, an apparatus for operating a hybrid propulsion system in a motor vehicle is provided, comprising:

• A control unit for operating the drive units according to an indication of a load distribution, the load distribution indicating a distribution of the services to be provided by drive units of the hybrid drive system; and
• - A transmitting / receiving device for transmitting a position information about a current position of the motor vehicle to the outside, in particular to an externally arranged from the motor vehicle central unit, and for receiving an indication of a load distribution in response to the transmission of the position information.

According to a further aspect, a hybrid drive system is provided with drive units, which comprise at least one electric drive and an electrical energy store for providing electrical energy for the electric drive, and the above device.

According to a further aspect, a central unit is provided for providing information about load distributions to one or more motor vehicles, wherein the central unit is designed to perform one of the above methods.

According to another aspect, there is provided a system comprising the above central unit and one or more hybrid drive systems provided respectively in automobiles.

Brief description of the drawings

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; and

2a and 2 B Flowcharts illustrating a method for operating the motor vehicle.

Description of embodiments

1 shows a motor vehicle 1 with a hybrid drive system 2 that is a first drive unit 3 and a second one of the first drive unit 3 different drive unit 4 having. The first drive unit 3 is with a first energy storage 5 connected, which provides energy in the first drive unit 3 can be converted into kinetic energy. The second drive unit 4 is with a second energy storage 6 connected, which provides energy in the second drive unit 4 can be converted into kinetic energy. The first drive unit 3 For example, as an internal combustion engine and the second drive unit 4 be designed as an electric drive. The first energy storage 5 may be a fuel tank for storing fuel and the second energy storage 6 an electrical energy storage, for example in the form of a rechargeable battery include.

The drive units 3 . 4 be from a control unit 7 controlled. The control unit is equipped with a transmitting / receiving unit 8th which is adapted to information about a central processing unit 20 to transmit and receive from this. Furthermore, the control unit 7 with a position detection unit 9 coupled, which may be part of the hybrid drive system or part of an external navigation system, to position data of the motor vehicle 1 to obtain. In particular, the position detection unit 9 a GPS receiver and the like.

The central unit 20 includes a computer system 21 that has a memory 22 and a transceiver unit 23 has to communicate with the transceiver unit 8th in the motor vehicle 1 bidirectionally exchange data.

In the 2a and 2 B are based on flowcharts in the hybrid propulsion system 2 and in the central unit 20 explained procedures explained. First, the procedure that is in the control unit 9 is executed in conjunction with 2a described. The control unit 9 determines the position of the motor vehicle in step S1 1 with the help of the position detection unit 9 , The position indication is sent to the central unit in a step S2 20 transmitted via a suitable data transmission protocol via radio link.

In addition to the position of the motor vehicle can also vehicle type, type of hybrid drive system 2 and further vehicle-specific information to the central unit 20 be transmitted. In the central unit 20 Now an indication of a load distribution based on the position of the motor vehicle 1 and the most likely to travel route within an electronic route horizon and determines this to the motor vehicle 1 returned. In addition, the indication of the load distribution may depend on the type of vehicle and / or the type of hybrid drive system 2 be determined.

In step S3, a dependent on the previously transmitted position of the motor vehicle 1 determined information about the load distribution by the transmitting / receiving unit 8th received and this in step S4 by appropriate control of the drive units 3 . 4 implemented. Subsequently, a return is made to step S1, so that the method can be carried out cyclically.

In the central unit 20 discloses a method of determining an indication of load distribution for a hybrid propulsion system 2 executed. This method is used in conjunction with the flow chart of 2 B described.

In step S11, the position information is first of all waited for and optionally received, so that these are stored in the central unit 20 ready.

Based on the position of the motor vehicle 1 In step S12, a most probable route of the motor vehicle is determined. The determination of a most probable path (MPP) of a motor vehicle 1 is known from the prior art and it is therefore not discussed in detail. In particular, a route planned in a navigation system can be assumed as the most probable route. The position of the motor vehicle 1 can with a classic navigation system by assignment to that in the central unit 20 stored digital road map can be customized.

The Electronic Lane Horizon corresponds to a most probable route to be traveled or a section thereof on which the predictive consideration for determining the indication of the load distribution is based. The electronic link horizon is made up of sections of track, each of which may be associated with one or more of the following information: lane gradient or lane slope information, curve curvature, legal speed limit, traffic volume, weather condition, and the like. Based on this information, in step S13 with the aid of a suitable hybrid operating strategy, for example based on a simple longitudinal dynamics model of the motor vehicle 1 , a predictive determination of a speed profile or a speed trajectory along the electronic route horizon made, resulting in accordance with an optimization method, such as an ECMS method, a curve of the load distribution results in a minimum fuel consumption over the electronic route horizon. The load distribution results from a state of charge of the electrical energy store, so that a specification of the desired state of charge for the electrical energy storage of the motor vehicle 1 can serve as an indication of the load distribution. Therefore, each of the position of the motor vehicle associated desired state of charge / load distribution to the hybrid drive system 2 of the motor vehicle 1 be transmitted.

The transmission of the current position of the motor vehicle 1 assigned set state of charge / load distribution takes place in step S14 using the transceiver unit 23 ,

Also the procedure in the central unit 20 is performed cyclically and in step S11 on the retransmission of the position information of the motor vehicle 1 maintained. In this way, by providing a central processing unit 20 a stored digital road map, including the route information needed to determine optimal fuel consumption, need only be stored once, so that updating such a digital road map in each of the motor vehicles is no longer necessary. In addition, significantly less computing power must be kept in the motor vehicle, since the optimization and determination of an optimized load distribution takes place externally. As a result, simpler control units can be used.

Claims (13)

Method for operating a hybrid drive system ( 2 ) with several drive units ( 3 . 4 ) in a motor vehicle ( 1 ) with the following cyclically executed steps: - transmission (S2) of a position information about a current position of the motor vehicle ( 1 ) to an external vehicle ( 1 ) arranged central unit ( 20 ); - in response to the transmission of the position information; Receiving (S3) an indication of a load distribution, the division of the drive units ( 3 . 4 indicates services to be provided; - operating (S4) the drive units ( 3 . 4 ) according to the indication of the load distribution. Method according to claim 1, wherein the drive units ( 3 . 4 ) an electric drive ( 4 ) comprising an electrical energy store ( 6 ) for supplying the electric drive ( 4 ) is connected to electrical energy, wherein the indication of the load distribution comprises a desired state of charge, wherein the electric drive ( 4 ) is operated with a power, so that an actual state of charge of the electrical energy storage ( 6 ) in the direction of the target Charge state is set or the state of charge is controlled to the desired state of charge. Method for operating a central unit ( 20 ) with the following cyclically executed steps: - receiving (S11) a position indication about a current position of one of the central unit ( 20 ) separate motor vehicle ( 1 ); Determining (S13) an indication via an optimized load distribution for drive units ( 3 . 4 ) of a hybrid propulsion system ( 2 ) of the motor vehicle ( 1 ) depending on the received position information, wherein the load distribution is a division of the drive units ( 3 . 4 indicates services to be provided; - Transmission (S14) of the indication of the optimized load distribution to the motor vehicle ( 1 ). The method of claim 3, wherein the indication of the optimized load distribution is determined depending on route parameters of a preceding route. The method of claim 4, wherein the indication of the load distribution is determined by determining a velocity trajectory along an electronic distance horizon and performing an optimization of the course of the load distribution along the velocity trajectory. The method of claim 5, wherein the electronic route horizon is determined as a most likely traveled route or a portion thereof. Method according to one of claims 3 to 6, wherein as an indication of the load distribution, a desired state of charge of an electrical energy store ( 6 ) of the hybrid drive system ( 2 ) is determined and transmitted. Device for operating a hybrid drive system ( 20 ) in a motor vehicle ( 1 ), comprising: - a control unit ( 7 ) for operating the drive units ( 3 . 4 ) according to an indication of a load distribution, the load distribution being a division of the drive units ( 3 . 4 ) of the hybrid drive system ( 2 indicates services to be provided; A transmitting / receiving device ( 8th ) for transmitting a position information about a current position of the motor vehicle ( 1 ) to external, in particular to an external of the motor vehicle ( 1 ) arranged central unit ( 7 ), and receiving an indication of a load distribution in response to the transmission of the position indication. Hybrid drive system with drive units ( 3 . 4 ), which has at least one electric drive ( 4 ) and an electrical energy store ( 6 ) for providing electrical energy for the electric drive ( 4 ), and an apparatus according to claim 8. Central unit for providing information about load distributions to one or more motor vehicles ( 1 ), the central unit ( 20 ) is adapted to perform one of the methods according to one of claims 3 to 7. System with a central unit ( 20 ) according to claim 10 and one or more in each case in motor vehicles ( 1 ) hybrid drive systems ( 2 ) according to claim 9. Computer program adapted to perform all the steps of a method according to any one of claims 1 to 7 when executed on a data processing device. A machine-readable storage medium on which a computer program according to claim 12 is stored.

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