DE102022205989A1 - Hybrid drive for a motor vehicle and method for operating the same - Google Patents

Abstract

The present development relates to a hybrid drive (10) for a motor vehicle (1), comprising: - an electric drive (12) for driving the motor vehicle (1), - a rechargeable traction battery (14) for supplying the electric drive (12) with electrical energy, - a power generation unit (16) for generating electrical energy from a fuel that can be carried in the motor vehicle (1), - an electronic control (50) which is designed to:a) a provided height profile of a route to be covered in at least a first and a second gradient class (70, 71, 72, 73, 74), b) for each of the at least first and second gradient classes (70, 71, 72, 73, 74) an electrical energy requirement and/or an electrical power requirement for the electric drive (12 ). To control or regulate the power generation unit (16).

Description

Technical area

The present development relates to a hybrid drive for a motor vehicle, a motor vehicle equipped with a hybrid drive, a method for operating such a hybrid drive and a computer program for carrying out such a method.

background

There are various implementations of hybrid drives for motor vehicles. In a serial hybrid drive, at least two energy converters are provided. A first energy converter can, for example, be designed as an electric motor and serve solely or predominantly for the traction of the vehicle. A second energy converter can be implemented as a power generation unit. The second energy converter does not need a mechanical connection to the actual drive axle. The second energy converter can fulfill the function of a so-called range extender. For example, the second energy converter can generate electrical energy by combustion or by electrochemical conversion of a fuel during operation of the motor vehicle, which can be used by the first energy converter, typically with the interposition of a rechargeable traction battery, to move the motor vehicle.

For such hybrid drives, it is typically provided that the second energy converter, such as the power generation unit, is only put into operation temporarily, for example in order to recharge a traction battery that is continuously discharging during operation of the motor vehicle and/or to provide additional drive torque. Typically, the second energy converter, i.e. the power generation unit, is put into operation when the state of charge of the energy storage reaches a lower threshold value.

For example, from the US 2021/0046918 A1 a system and a method are known for regulating the operation of an internal combustion engine and an electric motor, in particular for determining when the internal combustion engine should be activated or deactivated.

For efficient operation of the motor vehicle and for the most cost-effective and space-saving production of a motor vehicle equipped with a hybrid drive, it is fundamentally desirable to dimension the components of the hybrid drive, such as a traction battery, a power generation unit and the electric drive, in a coordinated manner.

In principle, it is possible for the electric drive to have a maximum electrical power consumption that is greater than the power generation output of the power generation unit. If the traction battery has sufficient charging capacity, such constellations are definitely desirable for reasons of cost and space. During continuous operation of the motor vehicle, the electric drive is not constantly operated close to its performance limit and the battery typically only has to supply the electric drive with maximum electrical power over a short period of time.

The temporary commissioning of the power generation unit is typically determined or triggered by the state of charge of the traction battery. For example, if the state of charge reaches a lower permissible threshold value, the power generation unit is typically put into operation in order to counteract a critical discharge of the motor vehicle battery in a timely manner.

However, if the power generation output of the power generation unit is smaller than, for example, a maximum nominal power of the electric drive, situations can arise in practice in which the charge level of the battery continues to fall below a critical value despite the power generation unit being activated; if at the same time the electric drive is operated with an extraordinarily high power consumption, which is required, for example, when driving uphill.

In this respect, one objective of the present development is to eliminate those disadvantages and to provide an improved hybrid drive and an improved method for operating a hybrid drive for a motor vehicle. The hybrid drive and the process should be implemented as cost-effectively and as space-saving as possible. The hybrid drive and the method should enable the most efficient, cost-effective and space-saving implementation of the components of the hybrid drive.

Advantageous configurations

To solve this problem, a hybrid drive, a motor vehicle, a method for operating a hybrid drive and a computer program are provided according to the features of the independent patent claims. Advantageous refinements are the subject of dependent patent claims.

In a first aspect, a hybrid drive is provided for a motor vehicle. The hybrid drive includes an electric drive for driving the motor vehicle. The hybrid drive also includes a rechargeable battery, which can also be referred to as a traction battery and which is designed to supply the electric drive with electrical energy. The traction battery can in particular be designed as a high-voltage battery. The hybrid drive also has a power generation unit for generating electrical energy from fuel that can be carried in the motor vehicle. The power generation unit acts as a range extender and can be used for onboard charging of the traction battery. The rechargeable traction battery can also be connected to a charging station via a plug-in solution, ie wired via a separate charging port.

The electronic control is designed to divide a provided height profile of a distance to be covered by the motor vehicle into at least a first and a second gradient class. The first gradient class indicates a frequency density of a first gradient range of the route to be covered. The second gradient class indicates a frequency density of a second gradient range of the route to be covered.

The route to be covered can be parameterized or characterized in particular with regard to several gradient classes. The first gradient class can, for example, reflect the information that approximately 70% of the route to be covered still has a gradient of less than 2.5%. The second gradient class can, for example, reflect that 20% of the route to be covered has a gradient in the range of 2.5% to 7.5%. Another gradient class can, for example, indicate that around 5% of the route to be covered has a gradient in the range of 7.5 to 12.5%.

In this respect, the electronic control is designed to characterize the height profile of the distance to be covered in the manner of a histogram based on several gradient classes. On the basis of that histogram, i.e. based on at least two gradient classes, an electrical energy requirement and/or an electrical power requirement for the electric drive can then be calculated for each, i.e. at least for the first and for the second gradient class. Such a calculation can be carried out on the electronic control side.

For each of the at least first and second slope classes, a power gap to a predetermined power of the power generation unit can also be predicted or calculated. This means that for each gradient class, using the known weight and load of the motor vehicle and based on an average speed of the motor vehicle, it can be calculated how much energy or how much power will be required by the electric drive for the relevant gradient class.

That power can under certain circumstances exceed the electrical power of the power generation unit, so that the hybrid drive must first build up a corresponding energy buffer, for example using the traction battery, to cope with the gradient class. The power gap or energy gap between the specified power of the power generation unit and the power requirement for each gradient class is an indication of a temporary undersupply of the electric drive with electrical energy directly from the power generation unit.

Based on those predicted performance and/or energy gaps, the controller can be designed to control or regulate the current operation of the power generation unit. In particular, the electronic control is designed to control or regulate the current operation of the power generation unit predictively, i.e. in a forward-looking manner. The evaluation of the histogram and the division of the height profile, provided via a navigation device, into different gradient classes enables effective and predictive control and correspondingly efficient operation of the power generation unit.

The power generation unit can be controlled or regulated directly based on the calculated or predicted power gap. However, further intermediate steps can advantageously be carried out, by means of which an optimized control or regulation of the power generation unit can take place.

For example, after a further development of the hybrid drive, the electronic control is further designed to calculate an energy gap for each gradient class based on the predicted power gaps and to control or regulate the current operation of the power generation unit based on the energy gaps of all or some power classes. For example, for each gradient class, knowing the weight and, for example, the payload of the motor vehicle, it is possible to precisely calculate what total amount of energy will be required, to move the vehicle according to each gradient class.

Of course, negative values can also arise here, namely when the vehicle is moved downhill, for example, and corresponding recuperation and energy recovery from kinetic energy into electrical energy takes place.

The determination or estimation of the energy gap and the calculation or forecast of all energy gaps for the individual gradient classes make it possible, in particular, to determine or predict a gradient class-specific energy requirement for the movement of the motor vehicle. The percentage distribution of the performance classes among each other in relation to the distance still to be covered can also be used to calculate or determine the total amount of energy that will be required to move the motor vehicle.

To calculate an energy gap based on each gradient class, histogram data or height profile data can also be made available to the electronic control directly from the navigation system of the motor vehicle and accordingly fed into the electronic control of the hybrid drive. To calculate the energy gap, the histogram data that changes over time can be taken into account in particular with regard to a division of the distance still to be covered into the individual gradient classes.

Furthermore, the total distance to be traveled as well as a forecast travel time can be taken into account when calculating the energy gaps related to the gradient classes. In this way and using the histogram data provided, for example, by a navigation device or navigation system with regard to individual gradient classes of the route still to be covered, particularly simple and efficient data processing can take place. Histogram data about the individual gradient classes can already be available in common navigation devices and can easily be made available to the electronic control of the hybrid drive, for example via a communication interface, for example via a vehicle-internal CAN bus.

According to a further embodiment of the hybrid drive, the electronic control is designed to calculate a target state of charge of the traction battery based on the calculated energy gaps for each gradient class and to control or regulate the power generation unit to maintain or achieve the target state of charge of the traction battery. In this way, a particularly efficient and data-technically easy to implement predictive, i.e. forward-looking control or regulation of the power generation unit can be carried out, so that in particular a needs-based and forward-looking control of the power generation unit can be provided.

Different energy gaps may arise for each of the individual slope classes. The electronic control sometimes does not know how the individual gradient classes are distributed over the distance to be covered. So only the percentages of different gradients or gradient classes of the distance still to be covered can be known by the electronic control.

The power generation unit can now be controlled and regulated in many different ways. For example, it is conceivable to use the maximum energy gap of all energy gaps of the individual gradient classes to control and regulate the power generation unit. In this way it would be ensured that a target state of charge of the traction battery is maintained or reached relatively quickly. However, it is also conceivable and, for reasons of energy efficiency, quite sensible to use some or all of the energy gaps in all gradient classes for the control or regulation of the power generation unit or at least to take these into account.

If, for example, it can be assumed that only a certain gradient class, which only has a comparatively small proportion of the distance to be covered, has a disproportionately high energy gap, it is clear that this energy gap will in fact not occur for a large part of the distance to be covered.

In this respect, after a further development of the hybrid drive, the electronic control can be designed to carry out the calculation of the target state of charge of the traction battery on the basis of a weighted selection of individual or several calculated energy gaps in the slope classes. Statistical evaluations of the individual slope classes can be used for an energy-efficient weighted selection or for a weighted selection that corresponds to the user specifications.

According to a further embodiment, the electronic control has an input interface via which a user can set or change a weighting factor for the weighted selection of individual or several calculated energy gaps of the gradient classes. If, for example, the user specifies that the hybrid drive should act to provide maximum driving comfort or maximum driving performance, the selection of individual or several calculated energy gaps in the gradient classes can be chosen in such a way that the target state of charge of the traction battery does not depend at all or only very slightly is deviated from and that the target charge level of the traction battery is reached quite quickly.

However, if the end user or user, for example, values particularly energy-efficient operation of the hybrid drive and a correspondingly changed weighting parameter is selected or set, certain deviations from the target state of charge of the traction battery can be tolerated at least over a certain period of time, so that the electronic The control is aimed at keeping the state of charge of the traction battery as low as possible and, if possible, operating the power generation unit in a power range in which the power generation unit has a high level of efficiency or the highest efficiency.

According to a further embodiment of the hybrid drive, the electronic control is designed to divide the height profile of the route to be covered into a number of further gradient classes, each of which reflects a frequency density of different gradient ranges of the route to be covered. The histogram of the height profile, which consists of several slope classes, can have approximately three slope classes, four slope classes, five slope classes, six slope classes or many more slope classes. The individual slope values of the slope classes do not overlap. Negative gradient classes, i.e. gradients, must also be taken into account accordingly and can be used as gradient classes to reflect the height profile accordingly.

With an increasing number of slope classes to be taken into account, an increasingly precise forecast of the actual energy consumption of the hybrid drive can be created and a correspondingly precise, forward-looking control or regulation of the power generation unit can be carried out.

According to a further embodiment of the hybrid drive, the electronic control is designed to carry out the individual steps for controlling or regulating the power generation unit on a continuously recurring basis. In particular, a constantly recurring calculation of the individual energy gaps in each gradient class can be constantly updated while the motor vehicle is traveling. That update takes place continuously during operation of the motor vehicle and while the motor vehicle is driving. In this respect, the histogram of the energy gaps of the individual slope classes is not a static but a dynamically varying quantity, which is ultimately used as an input variable on the electronic control side for selective, i.e. for predictive control or regulation of the power generation unit.

According to a further aspect, a motor vehicle is also provided which has a previously described hybrid drive. The motor vehicle can be implemented or designed as a passenger car, as a small van or as a bus.

Finally, according to a further aspect, a method for controlling a hybrid drive for a motor vehicle is provided. The hybrid drive has an electric drive for driving the motor vehicle, a rechargeable traction battery for supplying the electric drive with electrical energy, a power generation unit for generating electrical energy from a fuel that can be carried in the motor vehicle, and an electronic control. The method includes the steps of dividing or dividing a provided height profile of a route to be covered into at least a first and a second gradient class. The first gradient class reflects a frequency density of a first gradient range of the route to be covered. The second gradient class reflects a frequency density of a second gradient range of the route to be covered.

The method further includes calculating an electrical energy requirement and/or an electrical power requirement for the electric drive for each of the at least first and second gradient classes. Finally, a performance gap to a predetermined performance of the power generation unit is predicted for each of the at least first and second slope classes. The predetermined power of the power generation unit can be an ideal operating point of the power generation unit, at which the power generation unit has a maximum level of energy efficiency. The method ultimately includes controlling or regulating the current operation of the electricity generator performance aggregates based on the predicted performance gaps.

The method can be carried out or carried out in particular by means of the previously described hybrid drive for a motor vehicle. In this respect, all of the advantages, features and effects described above with regard to the hybrid drive also apply equally to the method for controlling the hybrid drive; and vice versa.

The method can be carried out or carried out in particular by means of an electronic control of the hybrid drive. The electronic control can in particular be implemented as a hybrid controller of the hybrid drive. The electronic control can be coupled, in particular in terms of data technology, to a navigation device or navigation system of the motor vehicle. Via this data-technical coupling, the electronic control can receive the data necessary for the predictive or forward-looking control or regulation of the power generation unit, in particular a height profile of a route to be covered and/or directly histogram data relating to individual gradient classes of the route to be covered. In particular, data that has already been prepared by the navigation system, such as histogram data or data characterizing the gradient classes, can be transferred directly from the navigation system to the electronic control. Embodiments of the hybrid drive and the method are also conceivable in which the division of the route to be covered into several gradient classes is already carried out by the navigation system and provided accordingly.

According to a further aspect, the present disclosure finally relates to a computer program comprising computer-readable instructions which, when the program is executed by an electronic control of a previously described hybrid drive, cause the latter to carry out the previously described method for operating the hybrid drive. In this respect, all features, advantages and effects mentioned with regard to the previously described hybrid drive and the previously described method also apply to the computer program; and vice versa.

The hybrid drive, the method and the computer program are designed in particular to provide a required driving resistance energy for active route guidance of a navigation device based on a distance or remaining distance still to be covered, for example also on the basis of an expected speed profile and an already known gradient profile of the route or route in accordance with the navigation data to determine which must be stored in the traction battery, for example, in particular for completing driving situations with high power requirements. Based on the expected incline sections on the planned route, by dividing the elevation profile into several incline classes and the data analysis based on this, an electrical power requirement of the electric drive can be predictively identified, which otherwise could not be covered by the power generation unit even at maximum power.

With the preventive and predictive control and regulation of the power generation unit proposed here, several advantages can be achieved. For example, the charge level of the traction battery can be significantly less energy stored in the battery than is normally intended, particularly when the distances to be covered are downhill or when the driving resistance power requirement is low. This increases the battery's recuperation potential. The battery can absorb significantly more electrical energy as a buffer storage, especially on long downhill gradients.

Any conversion losses due to an unnecessarily large amount of energy being charged in the battery and possibly discharged from the battery again can be avoided. Comparatively high battery charge levels generally have a negative effect on the lifespan of today's lithium-ion batteries. By proactively controlling or regulating the power generation unit, the battery charge level can be reliably reduced to a permissible minimum. Furthermore, through the predictive operation of the power generation unit, the power generation unit can be operated below its maximum output in a timely manner and over a longer period of time, which can have a positive effect on the service life of the power generation unit, in particular on the lifespan of a fuel cell as a power generation unit.

In terms of data technology, the electronic control is typically linked to a navigation system and is supplied at regular intervals via a suitable communication interface with updated data on the distance to be covered or the distance ahead. The data transmitted to the electronic control by the navigation system can show a remaining route route in kilometers, a relative distribution of individual speed classes on the remaining route and a relative distribution of the gradient classes the remaining distance included. The term “class” refers to statistical classes in the sense of a histogram-based distribution representation. At each calculation time, the navigation system can output the remaining distance as well as the expected relative proportions of the histogram classes until the end of route guidance. The respective proportions of the histogram classes are known based on the map material stored in the navigation system, or based on information about terrain data and speed restrictions or current traffic information, and can be calculated using the navigation system.

For the calculation of individual gradient ranges in each gradient class, a gradient force of the respective class acting on the motor vehicle and necessary for moving the motor vehicle can be calculated. The vehicle mass can first be estimated or measured or estimated using an algorithm. Based on the applicable gravitational acceleration, the vehicle mass and a reference helix angle of the respective class, which can also be calibrated, such a gradient force can be calculated or estimated for each class.

The calculation of the gradient performance is then based on the gradient force of the respective gradient class and can also include the efficiency of the electric drive system, which can be calibrated or estimated, for example, on the basis of characteristic maps.

Finally, an expected average speed can be calculated or predicted for each gradient class based on a reference speed of the respective class or based on a currently expected distribution of speed classes. Information about speed data, i.e. about a statistical distribution of the expected speeds of the motor vehicle over the distance to be covered, can also be read out from the navigation system and made available by the navigation system.

The power gaps for all slope classes can be calculated based on a difference or a power gap between the slope powers for each slope class and a reference power of the power generation unit. The reference power of the power generation unit can, for example, indicate the power points of the power generation unit, such as a fuel cell, at which the highest efficiency is present.

For each gradient class, an energy requirement can be calculated for each gradient class based on the performance gaps. Here, the time required to cover the respective incline section can be determined or predicted based on the remaining distance to be traveled and on the basis of the currently expected distribution of the incline classes as well as on the basis of the calculated average speed of the remaining distance.

A target state of charge of the traction battery typically results from the energy requirement or the energy gap and the theoretical reference capacity of the traction battery when fully charged. However, that energy gap can also take into account signals from a battery management software, whereby battery aging processes are also taken into account as the reference capacity of the battery, so that not the original charging capacity but an effective reference capacity adjusted for the aging process can be used to calculate or determine the reference capacity.

Due to the histogram-based calculation that is selected and can be carried out using the electronic control, the relative proportion of the respective gradient classes can be predicted, but not the chronological sequence of the expected gradients. In this respect, there is a certain uncertainty regarding energy buffering in the traction battery. In principle, this can lead to either too little or too much electrical energy being stored in the traction battery because the energy requirement has either been underestimated or overestimated over time.

Here, the weighted selection of individual or several calculated energy gaps of the gradient classes, taking into account a weighting factor specified or adjustable by the user, enables an adjustment option between maximum performance and efficient operation of the power generation unit. Since the electronic control permanently and continuously updates the gradient classes and their distribution over the remaining distance to be covered, the control and regulation of the power generation unit is constantly updated.

Short description of the characters

• 1 eine schematische Darstellung eines Kraftfahrzeugs,
• 2 ein Blockdiagramm des Hybridantriebs,
• 3 ein Diagramm, welches ein Höhenprofil einer Fahrstrecke zusammen mit Zustandsparametern des Kraftfahrzeugs nach dem Stand der Technik wiedergibt,
• 4 eine Darstellung unterschiedlicher Steigungsklassen und ihre zeitliche Entwicklung
• 5 eine Aufteilung der zu absolvierenden Fahrstrecke in unterschiedlichen Steigungsklassen zum Zeitpunkt t3,
• 6 ein Diagramm, welches diverse Zustandsparameter des Kraftfahrzeugs bei Nutzung des vorliegenden Hybridantriebs zeigt, und
• 7 ein Flussdiagramm des Verfahrens zum Betrieb des Hybridantriebs.

Further goals, features and advantageous refinements of the present development are explained in the following description of an exemplary embodiment. Show here:

• 1 a schematic representation of a motor vehicle,
• 2 a block diagram of the hybrid drive,
• 3 a diagram which shows a height profile of a route together with state parameters of the motor vehicle according to the prior art,
• 4 a representation of different slope classes and their development over time
• 5 a division of the route to be completed into different gradient classes at time t3,
• 6 a diagram showing various condition parameters of the motor vehicle when using the present hybrid drive, and
• 7 a flowchart of the method for operating the hybrid drive.

Detailed description

In 1 a motor vehicle 1, which is designed as a hybrid vehicle, is shown schematically. The motor vehicle 1 has a motor vehicle body 2 with an interior 3 functioning as a passenger cell. The motor vehicle 1 has a hybrid drive 10. This includes in particular a rechargeable or fillable energy storage device, for example in the form of a traction battery 14.

In the block diagram of the 2 the hybrid drive 10 is shown schematically. The hybrid drive 10 is designed as a serial hybrid drive. It has at least one electric drive 12, which is used for locomotion and traction of the motor vehicle. The torque that can be generated by the electric drive 12 can be transferred to the passable surface 34 via a chassis 26. The electric drive 12 is powered by a traction battery 14. To extend the range, the hybrid drive 10 has a power generation unit 16. The power generation unit 16 can be implemented as a fuel cell 17. The power generation unit 16 can in particular convert fuel carried in a tank 18 into electrical energy.

In further embodiments, it is conceivable that the power generation unit 16 makes the electrical energy to be generated available to an electrical bus system. Here, the electrical energy generated by the power generation unit 16 can also be made available directly to the electric drive 12 without intermediate storage in the traction battery 14. So only the excess electrical energy not used by the power generation unit 16 and the electric drive 12 can be fed into the traction battery 14.

The electrical energy that can be generated by the power generation unit 16 is supplied to the energy storage or the traction battery 14 via a converter 24. An on-board electrical system 22, for example a 12 V on-board electrical system of the motor vehicle 1, can be supplied with electrical power, for example from the battery 14, via the converter 24. The energy storage, i.e. the traction battery 14, can also be charged using an external charging or filling station via an on-board charger 28. The on-board charger 28 has a charging connection 29, which can be electrically coupled to a complementary charging connection of a charging station for charging the energy storage device 14.

Using the traction battery 14, a heater 30 and/or an air conditioning system 32 of the motor vehicle 1 can also be operated. The energy storage can in particular be designed as an electrical energy storage, for example as a traction battery 14 and/or as a supercapacitor.

The hybrid drive 10 can be operated in different operating modes. The hybrid drive 10 can drive the electric drive 12 in particular using electrical energy provided by the traction battery 14, as a result of which the vehicle 1 can be moved relative to the ground 34, for example on a road along a predetermined route. In such a traction mode, represented by arrow 36, electrical energy can be converted into kinetic energy. In a recuperation mode, indicated by arrow 38, kinetic energy of the motor vehicle can be converted back into electrical energy. If the motor vehicle 1 is driving, for example, on a slope, the electric drive 12 can be switched to a generator mode. The electric drive 12 acts as an electromechanical brake and can convert the kinetic energy or potential energy of the motor vehicle 1 into electrical energy, which in turn can be fed back into the energy storage 14.

In the diagram of 2 A situation is shown in which the hybrid drive is designed without the previously described electronic control and the power generation unit 16 is only controlled or regulated reactively. For example, a height profile 60 is shown over a distance S to be covered by the motor vehicle 1. Based on a corresponding vehicle speed, the vehicle drives up a first slope s1 at time t1. At time t2, the vehicle has reached the apex of the slope S1 and begins to travel downhill.

At a time t3, the vehicle is at the foot of another slope s2, the plateau of which is reached at time t4. Corresponding to the height profile 60 and below The upper diagram reflects the assumption that the motor vehicle 1 travels that height profile 60 at the specified times 3 individual vehicle conditions.

Graph 61 shows a constant target speed. Graph 62 reflects the actual vehicle speed. The graph 63 reflects the electrically producible power of the power generation unit, i.e. the power generation power 63, and the graph 64 shows the current charge status of the traction battery 14.

At the start of the journey, i.e. before time t1, the power generation unit 16 is switched off. The electric drive 12 draws its energy exclusively from the traction battery 14. As a result, the state of charge decreases continuously. At time t1, the state of charge reaches an upper threshold value N1, as a result of which a conventional control of a hybrid drive previously provided according to the prior art begins to activate the power generation unit 16. At the beginning of activation, the power generation unit 16 is operated at comparatively low power, since in particular the state of charge of the traction battery 14 is still comparatively high. However, if the initial operation of the power generation unit 16 coincides with climbing or driving on the first slope s1, this can lead to the traction battery 14 being discharged relatively quickly. At time t22, the state of charge 64 of the traction battery 14 can already reach a lower critical threshold N2.

After time t2, the vehicle travels down a slope, whereby the power of the power generation unit 16 can also be slightly throttled, since energy is fed into the traction battery 14 through recuperation. Between times t2 and t3, the vehicle 1 is moved at a comparatively low gradient. The energy consumption is correspondingly moderate. It can essentially be covered by the operation of the power generation unit 16. The traction battery 14 can only be discharged to a very small extent. However, the state of charge of the traction battery 14 is permanently close to the lower permissible threshold N2.

If the motor vehicle travels a further incline s2 at time t3, with a conventional control this results in the power generation unit 16 being operated at maximum power at time t3. However, this power is not sufficient to operate the electric drive 12 with the power required by the user. As a result, in order to protect the battery 14 against impermissible discharge, the power consumption of the electric drive 12 and, if necessary, the power consumption of other consumers of the motor vehicle 1 must be throttled, which results in a loss, i.e. a reduction in the speed of the motor vehicle at time t3.

In order to avoid this and to ensure the user of the motor vehicle the best possible driving comfort, the hybrid drive 10 proposed here provides for the distance to be covered to be divided into several gradient classes 70, 71, 72, 73, 74. The distance to be covered is therefore divided into different gradient classes, such as: 5 at a time t3 according to 4 are shown.

Accordingly, in the example shown here and in a snapshot at a time t3, the distance to be covered is divided into a first gradient class 70, a second gradient class 71, a third gradient class 72, a fourth gradient class 73 and a fifth gradient class 74. The first gradient class indicates in percentage terms what percentage of the distance to be covered has a gradient of less than 2.5%. The second gradient class 71 indicates the percentage of the distance still to be covered, which has a gradient between 2.5 and 7.5%. The third gradient class 72 indicates a percentage of the remaining route in the range between 7.5% and 12.5% gradient. The fourth gradient class 73 characterizes a gradient range between 12.5% and 17.5% and the fifth gradient class 74 characterizes the proportion of the distance still to be covered which has a gradient of more than 17.5%.

The percentage distribution of the individual slope classes is shown in the continuum representation 4 shown vertically. The time course of the percentage division into the individual classes is shown there in the form of horizontal lines. At time t3, about 76% of the distance still to be covered can be assigned to the first gradient class 70, 17% of the distance yet to be covered is to be assigned to the second gradient class 71, around 4% of the distance yet to be covered is to be assigned to the third gradient class 72, about 2% of the The distance still to be covered is assigned to the fourth gradient class 73 and around 1% of the distance to be covered is to the fifth gradient class 74.

A predictive control or regulation of the power generation unit 16 takes place using the method already described, which is based on the individual method steps 100 to 110 according to the flow chart 7 are shown again. The individual method steps 100 to 110 and the control method are typically carried out by the electronic control 50 of the hybrid drive 10.

In a first step 100, for example, an electrical energy requirement and/or an electrical power requirement are determined for each gradient class using data from the navigation system 52. For example, an expected average speed can be taken into account for each gradient class. Based on those calculations in step 100, a performance gap can be calculated for each slope class in a subsequent step 102. That power gap can be calculated in particular with regard to a predetermined power generation output of the power generation unit. In particular, the most efficient operating point of the power generation unit 16 can be used as a reference variable for the performance of the power generation unit.

In the subsequent step 104, a respective energy gap can be calculated for each gradient class based on the remaining distance and based on the predicted power gaps of the gradient classes. In the subsequent step 106, an energy gap for each performance class to the target state of charge of the traction battery can be calculated based on the energy gaps for each of the performance classes. In particular, the so-called State of Health (SoH) of the traction battery 14 can be taken into account. This means that signs of aging of the motor vehicle battery 14 and their negative effects on the maximum state of charge can be taken into account when calculating the energy gap.

In the subsequent step 108, the energy requirement can typically be determined in advance based on a weighted selection of individual or several calculated energy gaps of individual slope classes, which is used in the subsequent step 110 to control or regulate the power generation unit 16.

In step 108, in particular, one or more weighting factors can be taken into account, which can be selected or modified by the user via an input interface 51. In this way, the user can influence the control of the hybrid drive. The user can, for example, specify that the system should provide maximum driving comfort and should therefore be operated more to buffer energy in the traction battery 14 or as energy-efficiently as possible, with the state of charge of the traction battery being kept closer to or closer to a lower permissible level .

A vehicle condition diagram comparable to the diagram of the 3 is in 6 reproduced, which is based on a height profile 60 of 3 is based. Here, however, the electronic control 50 is active and the power generation unit 16 is controlled or regulated in a predictive, ie forward-looking, manner.

By evaluating the individual slope classes 70, 71, 72, 73, 74 and the power and energy gaps of the individual slope classes and through the weighted selection of individual energy gaps or power gaps for controlling or regulating the power generation unit, critical operating states of the entire system are largely avoided and the motor vehicle can the entire route can be moved at the intended target speed 61. At a time t1 and before the state of charge reaches the upper threshold value N1, the power generation unit 16 is already operated at a maximum power up to time t2, which correlates with the end of the slope s1.

After this, the performance of the power generation unit 16 can be throttled comparatively strongly, since the system recognizes that in the immediate time after time t2 there is a downhill section in which energy can be recovered through recuperation. Due to the predictive evaluation of the individual gradient classes, the system knows that a significant amount of energy must be provided to drive on the gradient s2. Therefore, in the period t2 'until time t3, at which the vehicle 1 reaches a second gradient s2, the power generation unit 16 is operated close to its maximum power. Compared to the situation according to the 3 Here, the state of charge of the traction battery 14 is at a significantly higher level, particularly in the time interval between t2 and t3.

At time t4 and when an altitude plateau has been reached and after the motor vehicle has already traveled over a large part of the altitude profile that has to be overcome, it is known throughout the system that in the future only comparatively low electrical energy will have to be provided for driving on further inclines. Therefore, at time t4, the output of the power generation unit 16 can be noticeably throttled.

Overall, the vehicle can be operated in a much more energy-efficient manner through the forward-looking and predictive control or regulation of the power generation unit 16. Phases in which that Power generation unit 16 is operated below its maximum power limit, can be extended and the power generation unit 16 can be used in the best possible and extremely efficient manner.

The embodiments shown merely show possible configurations of the development, for which numerous other variants are conceivable within the scope of development. The exemplary embodiments shown are in no way to be interpreted as limiting the scope, applicability or configuration options of the development. The present description merely shows the person skilled in the art one or a few possible implementation(s) of an exemplary embodiment. A wide variety of modifications can be made to the function and arrangement of the elements described without departing from the scope of protection defined by the following claims or its equivalents.

Reference symbol list

1

motor vehicle

2

Motor vehicle body

3

inner space

10

Hybrid drive

11

consumer

12

Electric drive

14

Traction battery

16

Electricity generating unit

17

Fuel cell

18

tank

22

On-board electrical system

24

converter

26

landing gear

28

Onboard charger

29

Charging port

30

Heating

32

air conditioner

34

underground

36

Traction

38

Recuperation

50

electronic control

51

Communication interface

52

navigation system

60

Elevation profile

61

Target speed

62

Is speed

63

Electricity generation capacity

64

charging status

70

Gradient class

71

Gradient class

72

Gradient class

73

Gradient class

74

Gradient class

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was 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

• US 20210046918 A1 [0004]

Claims (10)

Hybrid drive (10) for a motor vehicle (1), comprising: - an electric drive (12) for driving the motor vehicle (1), - a rechargeable traction battery (14) for supplying the electric drive (12) with electrical energy, - a power generation unit (16) for generating electrical energy from fuel that can be carried in the motor vehicle (1), - an electronic control (50), which is designed to: a) to divide a provided height profile (60) of a route to be covered into at least a first and a second gradient class (70, 71, 72, 73, 74), the first gradient class (70) being a frequency density of a first gradient range of the route to be traveled and wherein the second gradient class (71) reflects a frequency density of a second gradient range of the route to be covered, b) to calculate an electrical energy requirement and/or an electrical power requirement for the electric drive (12) for each of the at least first and second gradient classes (70, 71, 72, 73, 74), c) for each of the at least first and second slope classes (70, 71, 72, 73, 74) to predict a power gap to a predetermined power of the power generation unit (16), and d) to control or regulate the current operation of the power generation unit (16) based on the predicted performance gaps. Hybrid drive (10). Claim 1 , wherein the electronic control (50) is designed to calculate an energy gap for each gradient class (70, 71, 72, 73, 74) based on the predicted power gaps and to determine the current operation of the power generation unit (16) based on the energy gaps to control or regulate. Hybrid drive (10). Claim 2 , wherein the electronic control (50) is designed to calculate a target state of charge of the traction battery (14) based on the calculated energy gaps for each gradient class (70, 71, 72, 73, 74) and the power generation unit (16) to comply or to control or regulate to achieve the target state of charge of the traction battery (14). Hybrid drive (10). Claim 3 , wherein the electronic control (50) is designed to calculate the target state of charge of the traction battery (14) based on a weighted selection of individual or several calculated energy gaps of the gradient classes (70, 71, 72, 73, 74). Hybrid drive (10). Claim 4 , wherein the electronic control (50) has an input interface (51) via which a user can set or change a weighting factor for the weighted selection of individual or several calculated energy gaps of the slope classes (70, 71, 72, 73, 74). Hybrid drive (10) according to one of the preceding claims, wherein the electronic control (50) is designed to divide the provided height profile (61) of the route to be covered into a number of further gradient classes (70, 71, 72, 73, 74). , which each reflect a frequency density of different gradient ranges of the route to be covered. Hybrid drive (10) according to one of the preceding claims, wherein the electronic control (50) is designed to carry out steps a) - d) according to Patent claim 1 to be carried out on a recurring basis. Motor vehicle (1) with a hybrid drive (10) according to one of the preceding claims. Method for controlling a hybrid drive (10) for a motor vehicle (1), wherein the hybrid drive (10) has an electric drive (12) for driving the motor vehicle (1), a rechargeable traction battery (14) for supplying the electric drive (12) with electrical energy , a power generation unit (16) for generating electrical energy from a fuel that can be carried in the motor vehicle (1) and an electronic control (50), the method having the following steps: aa) dividing a provided height profile (60) of a route to be covered in at least a first and a second gradient class (70, 71, 72, 73, 74), the first gradient class (70) being a frequency density of a first gradient range of the route to be covered and the second gradient class (71) being a frequency density of a second gradient range of the route to be covered Reflects the route, bb) Calculating an electrical energy requirement and / or an electrical power requirement for the electric drive (12) for each of the at least first and second gradient classes (70, 71, 72, 73, 74), cc) Predicting a power gap to a predetermined power of the power generation unit (16) for each of the at least first and second gradient class (70, 71, 72, 73, 74), and dd) controlling or regulating the current operation of the power generation unit (16) based on the predicted performance gaps. Computer program comprising computer-readable instructions which, when the program is executed, are carried out by an electronic control (50) of a hybrid drive (10) according to one of the preceding Claims 1 until 7 These cause the method for operating a hybrid drive (10) to follow Claim 8 to carry out.

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