DE102015217937A1 - Operating multiple energy sources of a hybrid vehicle - Google Patents

Abstract

Provided is a method of operating a primary energy source (3, 103) and a secondary energy source (5, 105), the method comprising: receiving a signal (25) indicative of a target drive power (PLast) of the hybrid vehicle; Retrieving a first value (63) of a power consumption of the secondary energy source (5, 105) from the drive train (9, 11) associated with the target drive power, at which first value (63) energy consumption of the primary energy source (3, 103) and the secondary energy source (5, 105) is theoretically minimized upon generation of the target drive power (PLast) to the powertrain by means of the primary energy source and / or the secondary energy source under the condition that the secondary energy source receives energy; Retrieving one of the target drive power associated second value (65) of a power output of the secondary power source (5, 105) to the drive train (9, 11), at which second value, energy consumption of the primary energy source (3, 103) and the secondary energy source (5, 105) at Generating the desired drive power (PLast) on the drive train (9, 11) by means of the primary energy source and / or the secondary energy source with the proviso that the secondary energy source emits energy, is theoretically minimized; Selecting from the first value (63) and the second value (65) to obtain a selected value; Receiving or delivering a second power of the secondary power source to or from the powertrain corresponding to the selected value; Delivering a primary power source first power to the powertrain such that the sum of the first power and the second power provides the desired drive power.

Description

The present invention relates to a method for operating a primary energy source and a secondary energy source during a journey of a hybrid vehicle, wherein the primary energy source for delivering energy to a drive train of the hybrid vehicle is provided and wherein the secondary energy source for receiving energy from the drive train or for the delivery of energy the drive train is provided. Furthermore, the present invention relates to a control unit which is designed to carry out the method for operating the plurality of energy sources of the hybrid vehicle.

Conventional hybrid vehicles are equipped with multiple electrical and / or mechanical power sources and / or energy sources and / or torque sources. Additional degrees of freedom in providing the driver's desired drive power or source electrical power compared to the conventional internal combustion engine vehicle may result from combining multiple power sources (which may also provide power and / or torque) in the hybrid vehicle. In order to be able to operate these various energy sources appropriately, rule-based methods for power / torque distribution are known from the prior art. From the prior art is z. As the load following operation, an optimization-based method such as ECMS and calculation of globally optimal solutions before the start of the journey at a known distance known.

The publication DE 103 23 722 A1 discloses a method of determining a power split factor in hybrid vehicles, wherein the power split factor indicates the distribution of power produced by a fuel converter and an electric motor. An adapted equivalent factor is determined to weight an electric energy consumption value in a cost function, and the minimum of the power distribution factor dependent cost function is determined. The equivalence factors for charging and discharging an energy storage system may be estimated depending on the correlation between the fuel energy consumption value and the electric energy consumption value. In order to determine the power split factor between the power of a hybrid vehicle generated by a fuel converter and an electric motor, the adaptive equivalent factor for weighting a power split factor dependent electric energy consumption value is determined in a cost function, a minimum of the cost function is determined, and the power split factor for which the minimum is extracted the cost function has been achieved.

The publication DE 10 2008 007 119 A1 discloses a method of operating a hybrid vehicle, wherein the operation of the hybrid vehicle is dependent on the energy budget of the electric energy storage. The energy budget of the electric energy store is designed for free and costly energy production. An energy manager serves as an energy exchange and assesses the costs of generating energy in the form of free and costly energy. Depending on the energy balance of the electric energy storage takes a dynamic assessment, whether an electric driving is worthwhile or not.

Conventional rule-based methods do not always lead to optimal power sharing. This leaves u.U. a portion of the total savings potential for the primary energy unused. Furthermore, rule-based procedures must be specially adapted to the respective drive and are therefore not generally valid.

In order to calculate the globally optimal power / torque distribution, the distance to be traveled, including loads, must be known in advance. Furthermore, high accuracy is required for sufficient accuracy. Therefore, the calculation can not or only to a limited extent (for example, based on an estimated route and with low accuracy) during a trip in the vehicle. The actual distance traveled does not always have to correspond to the route underlying the calculation, which may require adjustments to the previously calculated distribution. Such methods are not always robust, since changing efficiencies can not be taken into account during operation. Furthermore, certain component constraints may be used in the calculation of the optimal power split, such as. B. predetermined gradients are not taken into account.

Real-time-capable, optimization-based methods require a computation-intensive optimization algorithm and thus a correspondingly high computing power. The efficiency maps of the power / torque sources must also be stored for application of these methods in the vehicle control unit, which can bring with it large amounts of data and a high application costs. Furthermore, such optimization-based methods are not always sufficiently robust, because a behavior in advance is not is foreseeable. Such methods can thus generate a control behavior or driving behavior that is not comprehensible to the driver.

An object of the present invention is to drive and / or operate two sources of energy in a hybrid vehicle such that power consumption is minimized while providing a driver desired desired torque and / or power within the powertrain of the hybrid vehicle. A further object of the present invention is to provide a control unit which is designed to execute or control a method according to the invention.

According to a first aspect of the present invention, there is provided a method of operating a primary energy source while driving a hybrid vehicle to deliver energy to a powertrain of the hybrid vehicle and a secondary energy source for receiving power from the powertrain or for delivering energy to the powertrain. The method has:
Receiving a signal indicative of a desired drive power of the hybrid vehicle;
Retrieving, at the first value, a power consumption of the primary power source and the secondary power source when generating the target drive power at the powertrain using the primary power source and / or the secondary power source, with the indication that the secondary power source receives power , theoretically minimized;
Retrieving a second power output value of the secondary power source associated with the target powertrain to the driveline, at which second power consumption of the primary power source and the secondary power source generating the target powertrain power via the primary power source and / or the secondary power source, with the secondary energy source providing power , theoretically minimized;
Selecting from the first value and the second value to obtain a selected value;
Receiving or delivering a second power of the secondary power source from or to the powertrain corresponding to the selected value;
Delivering a primary power source first power to the powertrain such that the sum of the first power and the second power provides the desired drive power.

During the journey, the hybrid vehicle can move at a speed greater than 0 relative to a roadway. While driving, the driver can set a certain target drive power z. B. define or specify by pressing the accelerator pedal. The target drive power may or may not be associated with a desired drive torque. The target drive power may represent the power that must be served by both power sources in total. This can be made up of the driving performance requirement, the power requirement of the auxiliary units and losses in the drive train. The signal can z. B. include an electrical and / or optical signal and / or radio signal. The first value of the power consumption and / or the second value of a power output can be retrieved from a memory of a control unit.

In any case, the primary energy source is designed for the delivery of energy to a drive train of the hybrid vehicle, for example for the delivery of mechanical or electrical energy to the drive train. The primary energy source does not necessarily have to be designed to absorb energy from the drive train of the hybrid vehicle. However, in other embodiments, the primary energy source may also be configured to receive energy from the powertrain. Both the primary energy source and the secondary energy source may deliver energy to the powertrain, or the primary energy source may deliver energy to the powertrain, and the secondary energy source may receive energy from the powertrain (which may be delivered from the primary energy source to the powertrain).

In the method, the case that the secondary energy source receives power and / or power from the powertrain, and the case that the secondary energy source supplies power and / or power to the powertrain are considered to be a first value of power consumption and a second value, respectively to retrieve a power output. The first value of the power consumption and the second value of the power output are in each case assigned to the desired drive power, that is to say in particular dependent on the desired drive power. The two cases are considered separately since a power input of the secondary power source from the powertrain is a different mode of operation than the power output of the secondary power source to the powertrain and therefore requires consideration of different parameters such as efficiencies which have an impact on energy consumption.

The selection of the first value or the second value may be based on various criteria:
For example, the selection of the first value or the second value may be dependent on the total energy consumption values and / or the savings values assigned to the respective values.

Further, the selection may be made in consideration of various constraints such as a minimum energy output from the secondary power source, or a minimum or maximum energy output from the primary power source to the powertrain, which may be desired for a variety of reasons such as to control the state of charge. In accordance with the selected value, the second power of the secondary source, which corresponds to the selected value, is then taken up by the drive train or delivered thereto. The services are considered signed, i. Power consumption and delivery are represented by different signs.

The sum of the first and second power is delivered to the powertrain. Thus, if the second power is negative, less than the first power is delivered to the powertrain. If the second power is positive, more than the first power is delivered to the powertrain. If the second power is negative, the secondary power source is charged. At a later time, the energy charged to the secondary energy source may be discharged again and delivered to the powertrain.

According to embodiments of the present invention, different efficiency characteristics of the power and torque sources and / or energy sources (ie, the primary energy source and the secondary energy source) for reducing primary energy consumption are achieved through appropriate power and / or torque and / or energy sharing. In this case, a suitable energy management can be derived from respective efficiency characteristics.

The first value (the power input of the secondary energy source from the powertrain) may be a first extreme position (eg, where maximum or minimum is assumed) of a power receiving function, which depends on the efficiencies of the primary and secondary energy sources, and at least on the desired drive power. wherein the first extreme position can be calculated before the journey and in particular stored in a memory. The extreme position could also be calculated while driving.

The second value (the power output of the secondary power source to the powertrain) may be a second extreme point of a power output function, which depends on the efficiencies of the primary energy source and the secondary energy source, as well as at least on the target drive power, the second extreme position was calculated before the trip and has been stored in particular ,

A complex optimization calculation can thus have been carried out "offline" in order to relieve a (engine) control unit of the hybrid vehicle while driving. The engine control unit only needs z. For example, for a given target drive power, retrieve the first value or the second value from memory without having to perform further optimization calculations. Thus, the engine control unit can be dimensioned smaller than conventionally required.

The first extreme point of the power consumption function is to be understood as a point at which the power consumption function assumes an extreme. The extremum can z. B. be a maximum (or a minimum). If the first value is used in the power consumption function, the power consumption function takes the extremum, e.g. As a maximum, on. When values around the first extreme are used in the power consumption function, the power consumption function gives values smaller than the maximum assumed at the first extremity. Inverse statements apply if the power consumption function at the first extreme position assumes a minimum.

The power consumption function and the power output function may, for. B. have been determined on a test bench, wherein a simulation or a plurality of waveforms have been recorded. For example, at a plurality of operating points, which z. B. are defined by a power and / or torque and a speed, efficiencies have been determined on the test bench, with the help of the power consumption function and / or the power output function were calculated or determined.

An efficiency can be defined as a quotient of a (effective usable) power and the sum of power and a power loss. The efficiency of an internal combustion engine can z. Example, as the quotient of a voltage applied to the drive train power and / or torque and the sum of the chemical performance of the fuel (taking into account the combustion enthalpy and a mass flow) and a heat dissipation performance can be determined. Other definitions are possible. In general, the efficiency may be defined as a quotient of the power actually provided to the outside and the power supplied to the corresponding power source. Other definitions are possible.

The first extremity or the second extremity may be selected depending on a first extreme value assumed by the power receiving function at the first extremity and / or a second extremum adopted by the power output function at the second extremity. The first extreme value is the value assumed by the power consumption function when the first extreme point is inserted into the power consumption function. The second extreme value is the value of the power output function assumed by the power output function at the onset of the second extreme.

The power consumption function may, for. B. represent the reduction of total losses by power consumption of the secondary source. The power delivery function may, for. B. represent the reduction of total losses by power output of the secondary source to the drive train. The objective may be to maximize the reduction in overall energy loss (the secondary energy source from the powertrain) and to maximize the reduction in total energy loss losses (the secondary energy source to the powertrain). The first extremity or second extremity can therefore be selected to maximize the reduction in overall losses. Other selection criteria may be added.

Alternatively or in combination, the first or the second extreme position can be selected depending on an energy content of the secondary energy source and / or depending on a driver's request. It can, for. For example, it may be desirable to maintain the energy content of the secondary energy source in a particular range during travel of the hybrid vehicle. This can also be determined as a function of an anticipated travel route and / or an anticipated travel route and / or travel time.

If z. B. is still a considerable distance to cover the journey, it may be desirable not to let the energy content of the secondary energy source to drop too much. On the other hand, when a destination is reached soon at which a charging facility is available, the energy content of the secondary power source can be more reduced. In order for a reliable operation of the hybrid vehicle can be guaranteed while boundary conditions can be met.

The first extremity can be selected if the energy content of the secondary energy source is below a lower energy content threshold. When the energy content of the secondary energy source is below the lower energy content threshold, it may be advantageous to recharge the secondary energy source, which is achieved by selecting the first value of the power input of the secondary energy source from the powertrain and receiving the second power of the secondary energy source from the powertrain.

The second extremity can be selected if the energy content of the secondary energy source is above an upper energy content threshold. If the energy content of the secondary energy source is above the upper energy content threshold, it may be advantageous to discharge the secondary energy source, which is achieved by selecting the second value of the secondary energy source power output to the powertrain and outputting the second secondary energy source power to the powertrain. Thus, the energy content of the secondary energy source can be maintained in a desired and / or required range to ensure safe, more reliable operation of the secondary energy source.

A plurality of first values for different target driving powers may be stored as a charging characteristic of the secondary power source. From this charging characteristic, the first value can be called up. Further, a plurality of second values for different target drive powers may be stored as a discharge characteristic of the secondary power source. From this discharge characteristic the second value can be called up. This simplifies retrieval of the first and / or second value.

The charging characteristic and / or the discharge characteristic can, for. B. be represented by suitable electronic data structures. According to a specification of the energy content of the secondary energy source, either the value of the charging characteristic or the value of the discharge characteristic can be selected. Other Selection criteria may be added, as stated above. Thus, the process in a simple manner z. B. be implemented as a program for a data processing system in a (engine) control unit.

The method may further comprise adjusting the charging characteristic and / or the discharging characteristic in dependence on driving efficiencies of the primary energy source and / or the secondary energy source and storing the adapted charging characteristic and / or the adapted discharge characteristic. Furthermore, the method may include retrieving the corresponding extreme positions from the adapted charging characteristic and / or from the adapted discharge characteristic. Thus, changing efficiencies can be considered while driving. The efficiencies can z. B. determined by detecting actually delivered to the drive train power compared to a reference power, which z. B. have been determined in complex measurements on a motor test bench. Other methods are possible.

The primary energy source may provide mechanical, electrical, or a combination of mechanical and electrical energy. The secondary energy source may provide mechanical, electrical, or a combination of electrical and mechanical energy.

The primary energy source may include one of the following:
an internal combustion engine with fuel tank;
an internal combustion engine with fuel tank and generator;
a fuel cell with hydrogen tank;
a redox flow battery.

The secondary energy source may include one of the following:
a rechargeable electric energy storage;
a rechargeable electric energy storage and an electric machine;
a flywheel;
a flywheel and an electric machine;
a compressed air reservoir;
a compressed air reservoir and a pneumatic motor;
a hydraulic motor and a hydraulic accumulator,

Thus, different primary and / or secondary energy sources can be supported. If the primary energy source comprises an internal combustion engine with a fuel tank, the first value and the second value can also be called up as a function of a rotational speed of the internal combustion engine. An operating point of the internal combustion engine can, for. B. depending on both a torque and / or power and the speed of the internal combustion engine can be defined.

According to another aspect of the present invention, there is provided a controller configured to execute or control a method of operating a plurality of power sources of a hybrid vehicle as described above in various embodiments.

Embodiments of the present invention will now be described with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments.

1 schematically shows a part of a hybrid vehicle with a control device according to an embodiment of the present invention, which is configured to perform a method for operating various power sources of the hybrid vehicle according to an embodiment of the present invention;

2 schematically illustrates a method of operating a primary power source and a secondary power source of a hybrid vehicle according to an embodiment of the present invention;

3 schematically illustrates an embodiment of a portion of a hybrid vehicle having a controller according to an embodiment of the present invention;

4 Figure 4 illustrates graphs with efficiencies considered in accordance with embodiments of the present invention;

5 illustrates characteristics that are determined and stored in accordance with embodiments of the present invention; and

6 illustrates a state of charge and / or an energy content of a secondary energy source, which is taken into account according to embodiments of the present invention.

1 schematically illustrates a part 1 a hybrid vehicle with a primary energy source 3 , a secondary energy source 5 , a (engine) control unit 7 , an electrical and / or mechanical connection 9 between the primary energy source 3 and the secondary energy source 5 and a drive train and / or drive wheel (and / or a load) 11 , where the control unit 7 is formed, a method for operating the primary energy source 3 and the secondary energy source 5 is formed according to an embodiment of the present invention.

The primary energy source 3 is symbolized by the arrow 13 for the delivery of energy to the electrical and / or mechanical connection 9 trained and thus to the drive train 11 educated. The secondary energy source 5 is both for absorbing energy from the electrical and / or mechanical connection 9 (and thus of the powertrain 11 ) as well as for the delivery of energy to the electrical and / or mechanical connection 9 and thus to the drive train 9 trained, as by the double arrow 15 is symbolized. The energy intake and / or energy release 13 . 15 can be z. B. delivery of mechanical and / or electrical energy.

The hybrid vehicle, part of which 1 in 1 is schematically illustrated, comprises (at least) two energy sources, consisting of the primary energy source 3 with unidirectional energy flow (PPU) and also consisting of the secondary energy source 5 with bidirectional energy flow (RPU), where in principle any can be used as the sole source of energy for vehicle propulsion. The energy sources 3 . 5 may provide both electrical power (such as batteries, fuel cell or internal combustion engine with generator) or mechanical power (such as internal combustion engine, electric motor, hydrostats or flywheel storage).

The energy consumption of the primary energy source 3 (PPU) represents the primary energy consumption that needs to be minimized by an appropriate energy management strategy (EMS). The state of charge (SOC) of the secondary energy source 5 (RPU) should be within defined limits and should vary depending on the application by a constant average (which may apply in particular to the full hybrid) or end of the journey against a minimum value strive (plug-in hybrid), so as possible the to be able to use all available secondary energy. The secondary energy is used while driving to operate both sources in such a way that the maximum efficiency of the entire system is achieved.

The primary energy source 3 can z. B. include an internal combustion engine with fuel tank. The secondary energy source 5 can z. B. include a rechargeable electric energy storage and / or an electric machine. The primary energy source can also z. Example, comprise a generator which is coupled via a mechanical connection to the internal combustion engine to generate powered by the internal combustion engine, electrical energy, in turn, to operate the secondary energy source 5 (eg charging an energy storage and / or operating an electric machine) can be used.

The control unit 7 transmits control signals 17 to the primary energy source 3 and transmits control signals 19 to the secondary energy source 5 , The control signals 17 . 19 In particular, define a first power, which is the primary energy source 3 to the connection 9 has to give. Further, the control signal controls 19 the secondary energy source 5 such that the secondary energy source 5 either power to the connection 9 (and / or to the drive train 11 ) or performance of the connection 9 (and / or from the drive train 11 ).

This is done by the controller 7 a method of operating while driving the hybrid vehicle, the primary energy source 3 for delivering energy to the powertrain 11 the hybrid vehicle and the secondary energy source 5 to absorb energy from the powertrain 11 or for delivering energy to the powertrain 11 performed as it is schematic in 2 as a procedure 21 is illustrated. In one process step 23 a signal is received 25 which is indicative of a target drive power of the hybrid vehicle. For example, the desired drive power may represent a desired drive power applied to the powertrain and / or drive wheel 11 should be effected.

The power of the primary energy source is designated by P _PPU . The power of the secondary power _source is denoted by P _RPU and the (on the powertrain 11 applied) drive power is designated by P _load (see also 5 ).

Before that in 2 illustrated method 21 was performed offline z. B. on a test bench, efficiency or loss performance maps of the primary energy source 3 and the secondary energy source 5 determined. Further, the efficiency or loss performance maps have been used to calculate characteristics (in particular, charge characteristics and discharge characteristics) that determine the optimal power distribution between the primary energy source 3 and the secondary energy source 5 depending on the load (ie, target drive power and / or target drive torque).

mit

P_Chg:

Anteil der Leistung der PPU mit der die RPU geladen wird

P_Last:

Vom Antrieb geforderte Leistung

η_PPU:

Wirkungsgrad der PPU bei P_PPU = P_Last

η_PPU,LS:

Wirkungsgrad der PPU bei P_PPU = P_Last + P_Chg

η_RPU:

Wirkungsgrad der RPU bei P_RPU = P_Chg

Under the requirement that the secondary energy source 5 Absorbs energy, P _PPU > P _load applies. The first value of the power consumption can be determined according to the following equation by finding a maximum point of a power consumption function:

With

P _Chg :

Share of the performance of the PPU with which the RPU is loaded

P _Last :

Power required by the drive

η _PPU :

Efficiency of PPU at P _PPU = P _load

η _{PPU, LS} :

Efficiency of PPU at P _PPU = P _load + P _Chg

η _RPU :

Efficiency of RPU at P _RPU = P _Chg

Under the requirement that the secondary energy source 5 Releases energy (discharging the RPU), P _PPU <P _load applies.

mit

P_Dis:

Leistung mit der die RPU entladen wird (negativ)

P_Last:

Vom Antrieb geforderte Leistung

η_PPU:

Wirkungsgrad der PPU bei P_PPU = P_Last

η_PPU,LS,X:

Wirkungsgrad der PPU bei oder für bei P_PPU = P_Last + P_Dis oder für P_PPU = 0 bei P_PPU = P_Last + P_Chg

η_RPU:

Wirkungsgrad der RPU bei P_RPU = P_Dis

The second value of the power output can be determined according to the following equation by finding a maximum point of a power output function:

With

P _Dis :

Performance with which the RPU will be unloaded (negative)

P _Last :

Power required by the drive

η _PPU :

Efficiency of PPU at P _PPU = P _load

η _{PPU, LS, X} :

PPU efficiency at or for P _PPU = P _Load + P _Dis or for P _PPU = 0 at P _PPU = P _Load + P _Chg

η _RPU :

Efficiency of RPU at P _RPU = P _Dis

The equations (1) and (2) defined above apply to all variants of the primary and secondary energy sources of the described hybrid vehicle.

In a further step 27 of in 2 illustrated method 21 a retrieval takes place (in particular from an electronic memory 29 of the control unit 7 ) of a first value associated with the target drive power (eg according to equation (1)) of a power consumption of the secondary energy source 5 from the connection 9 and / or the powertrain 11 , at which first value energy consumption of the primary energy source 3 and the secondary energy source 5 when generating the target drive power 25 at the connection 9 and / or the powertrain 11 by means of the primary energy source 3 and / or the secondary energy source 5 under the requirement that the secondary energy source 5 Energy is absorbed, theoretically minimized.

In a further process step 31 is from the controller 7 from the store 29 a second value associated with the desired drive power (eg according to equation (2)) of a power output of Secondary energy source to the powertrain 9 . 11 at which second value energy consumption of the primary energy source 3 and the secondary energy source 5 upon generating the desired drive power on the drive train 9 . 11 by means of the primary energy source 3 and / or the secondary energy source 5 under the requirement that the secondary energy source 5 Gives off energy, is theoretically minimized. In this case, there is not just the primary energy source 3 but also the secondary energy source 5 Energy to the drive train 9 . 11 from.

The first value corresponds to the point at which a maximum of the power consumption function is assumed, as defined in equation (1). The second value corresponds to a second maximum location of the power output function as defined in equation (2).

In the further process step 31 is selected from the first value and the second value to obtain a selected value. In a further process step 33 the second power is received by the secondary power source from the powertrain, or the second power is delivered from the secondary power source to the powertrain, which corresponds to the selected value.

Furthermore, in a further method step 35 a first power of the primary energy source 3 to the drive train 9 . 11 so that the sum of the first power and the second power gives the target drive power.

The functions defined on the right side of Equations (1) and (2) may represent as a function value the reduction of the total power dissipation caused by the charging of the secondary power source 5 is achieved by the charging power P _chg , or reducing the total power loss, which by discharging the secondary _{energy source} 5 reached with the discharge power P _Dis . For equation (1), the charging power of the secondary power source becomes 5 for which the reduction in total power loss is maximized. When specifying a discharge of the secondary energy source 5 According to the equation (2), the discharge power is determined for which the reduction of the total power loss is maximized. The relationship P _Last = P _PPU + P _RPU always applies.

Before performing the procedure 21 which is shown schematically in FIG 2 is illustrated, a charging characteristic and a discharge characteristic of equations (1) and (2) in dependence on the target drive power P _load can be determined and in the control unit 7 (in particular designed as an EMS control unit) can be applied. During the journey, a sensible power distribution can then be selected as a function of the required power (target drive power).

Optionally, the characteristic curves (that is to say charging characteristic and / or discharge characteristic curve) can be adapted or changed with the aid of the component efficiencies actually occurring during operation.

3 to 6 illustrate an application of the method for operating various energy sources of a hybrid vehicle, wherein 3 a part 101 of the hybrid vehicle is shown. Elements that are the same or similar in structure and / or function are described in U.S. Pat 1 and 3 provided with reference numerals which are the same in the last two places.

The part 101 of in 3 illustrated exemplary hybrid vehicle includes as a primary energy source 103 a fuel cell system and includes as a secondary energy source 105 a battery. The rest of the structure is similar or similar to the structure of in 1 Abstract illustration of hybrid vehicle part 1 so that a description of the corresponding features of the 1 provided description can be taken.

4 illustrates the graphs 37 and 39 which z. B. on a test bench (offline) by measuring the energy sources 103 and 105 can be obtained. The graph 37 represents in a coordinate system with abscissa 41 (Performance of the fuel cell system 103 ) and ordinate 43 (Efficiency of the fuel cell system 103 ) the efficiency curve 45 of the fuel cell system 103 With increasing performance of the fuel cell system, the efficiency initially increases sharply and drops after reaching a maximum with increasing performance. The graph 39 shows in a coordinate system with abscissa 47 (State of charge of the battery 105 ) and ordinate 49 (Power of the battery 105 ) Isolines 51 with each at the isolines 51 The efficiencies shown in the graphs 37 and 39 of the 1 are used in the above equations (1) and (2) to obtain characteristics as shown in FIG 5 are shown.

5 Illustrates to a charging characteristic 53 and a discharge characteristic 55 in a coordinate system with abscissa 57 (Target drive power P _load ) and with an ordinate 59 (Fuel cell performance). The fuel cell system performance thus corresponds to the variable P _PPU . When charging the battery 105 P _PPU > P _load and when discharging the battery 105 P _PPU <P _load . At a given desired drive torque 61 (eg, pedal position of an accelerator pedal) becomes one of the target drive power 61 assigned first value 63 a power consumption of the battery 105 accessed. Further, one of the target drive power becomes 61 assigned second value 65 a power output of the battery 105 accessed.

In the 5 illustrated characteristics 53 . 55 For optimum power distribution, it is possible to directly derive analytically from the efficiency characteristics of the power and torque sources, so that dependencies can be shown. The equations (1) and (2) used are applicable to any energy source. Because the characteristics 53 . 55 in the run-up (that is before the start of the journey) can be calculated and this in the connection to the control unit 7 . 107 to be applied is in the control unit 7 . 107 only a small amount of calculation power is required for operation. Furthermore, the application of pre-defined rules results in a robust operating strategy. A direct assignment of load to power distribution can result in a reproducible driving behavior.

As in 5 illustrated, there are two characteristics, a charging characteristic 55 and a discharge characteristic for the secondary power source 5 . 105 , According to the component requirements or other boundary conditions, the state of charge can be controlled via this and still an energy-efficient operation can be ensured. Spontaneous adaptations of the state of charge can result, for example, from the current operating data of the components or also from driver inputs.

The primary energy source can, for. Example, an internal combustion engine with a tank (mechanical load), a combustion engine with tank and generator (electrical load), a fuel cell with a hydrogen tank (electrical load), a redox flow battery (electrical load).

The secondary energy source may, for. B. Ultra-Caps / Li-Caps (electrical load), Ultra Caps / Li-Caps + electric machine (mechanical load), flywheel storage (mechanical load), flywheel storage with electric machine (electric load), compressed air storage, hydraulic motor with hydraulic accumulator (mechanical load ), Compressed air reservoir with pneumatic motor (mechanical load) include. It should be noted that generally any secondary energy source suitable for a mechanical load can be upgraded with an electric load drive by an additional electric machine. If the hybrid vehicle has an internal combustion engine and battery, then an optimal power distribution between the primary energy source and the secondary energy source depending on torque and speed can result, resulting in the characteristics 53 . 55 in 5 still depending on another dimension. The characteristics 53 . 55 can be calculated offline and then quickly and easily applied in the vehicle. It is only a small amount of computing power in the control unit 5 required because no optimization within the controller 7 must be done while driving.

• a) Falls es erwünscht ist, einen Energieinhalt der Batterie 105 zu halten, kann eine Auswahl aus der Ladekennlinie 53 und der Entladekennlinie 55 derart erfolgen, dass im Mittel die der Batterie 105 entnommene Energie der zurückgespeisten Energie entspricht und dass dabei die maximale Einsparung entsprechend der oben aufgeführten Gleichungen (1) und (2) erreicht wird. Als Anmerkung sei erwähnt, dass zusätzlich während des Betriebs die Sekundärenergiequelle durch Rekuperation, durch Rückgewinnung der Bremsenergie, geladen wird. Für den Fall, dass diese Steuerung dennoch zu einem steigenden Energieinhalt der Sekundärenergiequelle 5 bzw. 105 führt, kann die Grenze, bis zu der ein ausschließlich elektrisches Fahren durchgeführt wird, angehoben werden. Dies kann der Wert der Entladekennlinie 55 sein, bis zu dem rein elektrisch gefahren wird.
• b) Falls gewünscht ist, dass der Energieinhalt der Sekundärenergiequelle 105 bzw. 5 sinkt, kann die Entladekennlinie 55 bevorzugt werden, so dass der Energieinhalt (SOC) der Sekundärenergiequelle 5, 105 im Mittel mit dem gewünschten Gradienten sinkt. Zusätzlich kann die Grenze, bis zu der ausschließlich elektrisch gefahren wird, angehoben werden.
• c) Falls gewünscht ist, dass der Energieinhalt der Sekundärenergiequelle 5, 105 ansteigt, kann die Ladekennlinie 53 bevorzugt werden, das heißt bevorzugt aus dieser Ladekennlinie der erste Wert abgerufen werden, so dass der Energieinhalt (SOC) im Mittel mit dem gewünschten Gradienten steigt.

During a driving operation, the power distribution between the fuel cell 103 and the battery 105 z. B. following rules:

• a) If desired, an energy content of the battery 105 to hold a selection from the charging characteristic 53 and the discharge characteristic 55 such that on average that of the battery 105 taken energy corresponds to the energy fed back and that while the maximum savings according to the above equations (1) and (2) is achieved. It should be noted that in addition during operation, the secondary energy source is charged by recuperation, by recovering the braking energy. In the event that this control nevertheless to an increasing energy content of the secondary energy source 5 respectively. 105 leads, the limit up to which only electric driving is performed, can be raised. This can be the value of the discharge characteristic 55 be up to which is driven purely electric.
• b) If desired, the energy content of the secondary energy source 105 respectively. 5 decreases, the discharge characteristic can 55 be preferred, so that the energy content (SOC) of the secondary energy source 5 . 105 decreases on average with the desired gradient. In addition, the limit up to which only electric driving is raised.
• c) If desired, the energy content of the secondary energy source 5 . 105 increases, the charging characteristic 53 are preferred, that is, preferably from this charging characteristic of the first value are retrieved, so that the energy content (SOC) increases on average with the desired gradient.

6 illustrated in a coordinate system with an abscissa 67 (Time) and with an ordinate 69 (Energy content of the secondary energy source 5 . 105 , SOC) over time 71 the energy content and / or the state of charge (SOC) of the secondary energy source 5 respectively. 105 , How out 6 is apparent, the actual state of charge moves 61 between a lower energy content threshold and / or state of charge threshold 73 and an upper energy content threshold and / or state of charge threshold 75 ,

In the period of time indicated by a) holding the state of charge is desired, which is achieved by the measures as described above. In the period indicated by b), a lowering of the state of charge is desired, which is achieved by the measures set out above under b). In the period of time indicated by c), an increase in the state of charge is desired, which is achieved with the measures set forth under c) above.

Embodiments of the present invention provide a robust operating strategy and predictable and reproducible drivability through the direct allocation of load (specifically, desired drive torque) for power sharing. It is an energy-efficient or almost consumption-optimal operation regardless of the state of charge of the secondary energy source achieved by optimal charge and discharge characteristic.

LIST OF REFERENCE NUMBERS

1

Part of the hybrid vehicle

3

Primary energy source (PPU)

5

Secondary energy source RPU)

7

control unit

9

electrical / mechanical connection

11

Drive train with drive wheel

13

energy output

15

Energy release or energy intake

17

control signal

19

control signal

21

Method for operating two energy sources

23

step

25

Signal of nominal drive power

27

step

29

electronic memory

31

step

32

step

33

step

35

step

37

graph

39

graph

41

abscissa

43

ordinate

45

efficiency curve

47

abscissa

49

ordinate

51

Isolines have the same efficiency

53

Charging characteristic

55

discharge characteristic

57

abscissa

59

ordinate

61

Target driving power

63

first value

65

second value

67

abscissa

69

ordinate

71

Time course of state of charge

73

lower state of charge threshold

75

upper charge state threshold

103

fuel cell

105

battery

η

efficiency

P

power

P _PPU

Power of the primary energy source

P _RPU

Power of the secondary energy source

P _load

Power on the drive train

P _FC

Power of the fuel cell

t

Time

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 10323722 A1 [0003]
• DE 102008007119 A1 [0004]

Claims (10)

Method for operating a primary energy source ( 3 . 103 ) during a drive of a hybrid vehicle for the delivery of energy to a drive train ( 9 . 11 ) of the hybrid vehicle and a secondary energy source ( 5 . 105 ) for receiving energy from the drive train ( 11 ) or for the delivery of energy to the drive train ( 9 . 11 ), the method comprising: receiving a signal ( 25 ) indicative of a target drive power (P _load ) of the hybrid vehicle; Retrieving a first value associated with the target drive power ( 63 ) a power consumption of the secondary energy source ( 5 . 105 ) of the drive train ( 9 . 11 ), at which first value ( 63 ) an energy consumption of the primary energy source ( 3 . 103 ) and the secondary energy source ( 5 . 105 ) is theoretically minimized upon generation of the target drive power (P _load ) on the drive train by means of the primary energy source and / or the secondary energy source, with the proviso that the secondary energy source receives energy; Retrieving a second value associated with the desired drive power ( 65 ) a power output of the secondary energy source ( 5 . 105 ) to the drive train ( 9 . 11 ), at which second value energy consumption of the primary energy source ( 3 . 103 ) and the secondary energy source ( 5 . 105 ) upon generation of the target drive power (P _load ) on the drive train ( 9 . 11 ) is theoretically minimized by means of the primary energy source and / or the secondary energy source, with the proviso that the secondary energy source gives off energy; Select from the first value ( 63 ) and the second value ( 65 ) to obtain a selected value; Receiving or delivering a second power of the secondary power source to or from the powertrain corresponding to the selected value; Delivering a primary power source first power to the powertrain such that the sum of the first power and the second power provides the desired drive power. Method according to claim 1, wherein the first value ( 63 ) is a first extreme point of a power consumption function which depends on the efficiencies ( 45 . 51 ) of the primary energy source ( 3 . 103 ) and the secondary energy source ( 5 . 105 ), and at least depends on the target drive power, wherein the first extreme point was calculated before the drive, wherein the second value ( 65 ) is a second extreme point of a power output function which depends on the efficiencies ( 45 . 51 ) of the primary energy source ( 3 . 103 ) and the secondary energy source ( 5 . 105 ), as well as at least depends on the target drive power, the second extreme point was calculated before driving.  Method according to claim 2, wherein the first extreme point or the second extreme position dependent from a first extreme value assumed by the power consumption function at the first extreme position, and from a second extreme value adopted by the power output function at the second extreme. Method according to one of the preceding claims 2 or 3, wherein the first extremity or the second extremity depending on an energy content (SOC, 71 ) of the secondary energy source ( 5 . 105 ) and / or is selected depending on a driver's request. Method according to one of the preceding claims 2 to 4, wherein the first extreme point is selected if the energy content (SOC, 71 ) of the secondary energy source ( 5 . 105 ) below a lower energy content threshold ( 73 ), the second extremity being selected if the energy content (SOC, 71 ) of the secondary energy source above an upper energy content threshold ( 75 ). Method according to one of the preceding claims, wherein a plurality of first values for different nominal drive powers as a charging characteristic ( 53 ) of the secondary energy source is stored, from which charging characteristic the first value ( 63 ), wherein a plurality of second values for different nominal drive powers as the discharge characteristic ( 55 ) of the secondary energy source is stored, from which discharge characteristic the second value ( 65 ), wherein according to a specification of the energy content of the secondary energy source, either the value of the charging characteristic or the value of the discharge characteristic is selected. Method according to one of the preceding claims, further comprising: adjusting the charging characteristic and / or the discharge characteristic in dependence on while driving certain efficiencies of the primary energy source and / or the secondary energy source; and storing the adjusted charge characteristic and / or the adjusted discharge characteristic. Method according to one of the preceding claims, wherein the primary energy source ( 3 . 103 ) and / or the secondary energy source ( 5 . 105 ) provides electrical and / or mechanical energy. Method according to one of the preceding claims, wherein the primary energy source ( 3 ) one of the following comprises: an internal combustion engine with fuel tank; an internal combustion engine with fuel tank and generator; a fuel cell with hydrogen tank; a redox flow battery; where the secondary energy source ( 5 ) one of the following comprises: a rechargeable electrical energy store; a rechargeable electric energy storage and an electric machine; a flywheel; a flywheel and an electric machine; a compressed air reservoir; a compressed air reservoir and a pneumatic motor; a hydraulic motor and a hydraulic accumulator, wherein, if the primary energy source includes an internal combustion engine with fuel tank, the first value and the second value are further retrieved in response to a rotational speed of the internal combustion engine. Control unit ( 7 . 107 ), which is designed, a method ( 21 ) according to one of the preceding claims.

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