Methods for operating a hybrid vehicle and hybrid vehicle

Abstract

The invention relates to a method for operating a hybrid vehicle (10) in which the hybrid vehicle (10) comprises an internal combustion engine (22), a charging device (30), at least one electric motor (34), a traction battery (28), drive wheels (14, 16), and a navigation system (39). A drive shaft (37) of the electric motor (34) is coupled or can be coupled to the drive wheels (14, 16) for torque transmission. The charging device (30) is configured to charge the traction battery (28) by converting the drive power of the internal combustion engine (22) into electrical energy by means of the charging device (30). Based on a route profile of an upcoming journey determined by the navigation system (39) and based on the current state of charge of the traction battery (28), the power output of the internal combustion engine (22) is planned.In this process, the power output of the internal combustion engine (22) is limited to a limiting power output that depends on the vehicle speed.

Description

[0001] The invention relates to a method for operating a hybrid vehicle according to the preamble of claim 1. Furthermore, the invention relates to a hybrid vehicle.

[0002] DE 10 2019 207 506 A1 shows a method for optimizing the operation of a motor vehicle with an internal combustion engine, among other things depending on a preceding route profile.

[0003] DE 10 2008 015 046 A1 and DE 10 2018 212 519 A1 each disclose a method for predictive control and / or regulation of a hybrid drive in a motor vehicle.

[0004] DE 10 2018 220 572 A1 also shows a method for predictive drive control of a hybrid vehicle, in which, among other things, the power output of an internal combustion engine is limited to a limit power dependent on a vehicle speed during a route profile.

[0005] The object of the present invention is to create a method for operating a hybrid vehicle and such a hybrid vehicle, so that a particularly advantageous operation of the hybrid vehicle can be realized.

[0006] This problem is solved by a method with the features of claim 1 and by a hybrid vehicle with the features of claim 5. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0007] A first aspect of the invention relates to a method for operating a motor vehicle, also referred to simply as a vehicle, configured as a hybrid vehicle, which is preferably configured as a motor car, in particular as a passenger car. In the method, the hybrid vehicle has an internal combustion engine, also referred to as an internal combustion engine, combustion engine, or motor, by means of which the hybrid vehicle can be driven. In particular, the hybrid vehicle is driven by the internal combustion engine at least during part of the method. In the method, the hybrid vehicle also has a traction battery in which electrical energy, in particular electrochemically, is to be stored or is stored. The traction battery is also simply referred to as a battery and is a secondary battery, which is also referred to as an accumulator or battery.In particular, the traction battery is a high-voltage component whose electrical voltage, especially its operating or nominal voltage, is preferably greater than 50 volts (V), particularly greater than 60 V, and most preferably several hundred V. Thus, the traction battery is referred to as an HV battery (high-voltage battery). In this method, the hybrid vehicle has a charging device by means of which the traction battery can be charged. This means that electrical energy can be provided by means of the charging device, which can be stored in the traction battery, i.e., stored in the traction battery, thereby charging the traction battery and thus increasing the amount of electrical energy stored in the traction battery. In this method, the hybrid vehicle also has at least one electric motor, which is also referred to as the first electric motor.Whenever the electric motor or at least one electric motor is mentioned before and below, this refers, unless otherwise specified, to the first electric motor. The electric motor is an electric machine, which is also referred to as the first electric machine. In particular, the motor vehicle can be driven by means of the electric motor. For this purpose, the electric motor can be operated in motor mode, that is, in a motor mode in which the motor vehicle can be driven or is driven by means of the electric motor. Most preferably, the electric motor is a high-voltage component whose electrical voltage, in particular its electrical operating or nominal voltage, is preferably greater than 50 V, more particularly greater than 60 V, and most preferably several hundred V.In particular, the electric motor can be powered by the electrical energy stored in the traction battery, thus enabling its operation in motor mode, especially for propelling the vehicle. Furthermore, it is conceivable that the electric motor can operate in generator mode, thereby converting the vehicle's kinetic energy into electrical energy, which can be supplied by the generator and stored, for example, in the traction battery, specifically for charging the traction battery.

[0008] In this process, the hybrid vehicle has drive wheels. For example, the hybrid vehicle has at least or exactly two axles arranged one behind the other in the longitudinal direction of the vehicle, namely a first axle and a second axle. The axles are also simply referred to as axles. Each axle has at least or exactly two wheels. The wheels of each axle are located on opposite sides of the vehicle in the transverse direction. The wheels of the hybrid vehicle are ground contact elements by which the vehicle can be supported or is supported downwards against the ground in the vertical direction.When the hybrid vehicle is driven along the ground while supported downwards by the ground contact elements in the vehicle's vertical direction, the ground contact elements roll along the ground, particularly directly. The wheels of the first axle are also referred to as the first wheels, and the wheels of the second axle are also referred to as the second wheels. For example, the drive wheels are the first wheels and / or the second wheels. Specifically, the drive wheels can be powered by the internal combustion engine, thus propelling the entire vehicle. Furthermore, the drive wheels can be powered by the electric motor, thus propelling the entire vehicle.

[0009] In this process, the hybrid vehicle has a navigation system, also referred to as a navigation device or designed as such. In particular, the navigation system can be used to determine the hybrid vehicle's position on Earth, especially its current position, particularly using satellites. Thus, the navigation system is, for example, a satellite-based navigation system that uses satellites to determine the vehicle's current position on Earth.Furthermore, for example, a route, also simply called a route, can be planned using the navigation system, which is drivable or ready for departure by the hybrid vehicle and extends, for example, from a first location as the starting point to a second location as the destination, so that by driving on or off the route, the hybrid vehicle can be driven from the starting point to the destination.

[0010] In this method, a drive shaft of the electric motor is coupled, or can be coupled, to the drive wheels in a torque-transmitting manner, so that the drive wheels can be driven by the drive shaft and thus by the electric motor. This allows the vehicle as a whole to be driven. The electric motor, for example, has a stator and a rotor, which can be driven by means of the stator and thus rotated about a machine axis relative to the stator. In particular, the rotor is permanently connected to the drive shaft in a rotationally fixed manner, so that by driving the rotor, the drive shaft can be driven and thus rotated about the machine axis relative to the stator. In particular, the electric motor can provide drive torques via its drive shaft to drive the wheels. Thus, by driving the drive shaft, the drive wheels, and therefore, for example, the vehicle as a whole, can be driven.

[0011] The charging device is designed to charge the traction battery by converting the drive power of the internal combustion engine into electrical energy. In other words, the internal combustion engine has, for example, an output shaft, particularly a crankshaft, through which it can provide drive power and thus drive torque to propel the drive wheels or the vehicle. The charging device is driven by the drive power of the internal combustion engine, thereby converting the drive power into electrical energy. This electrical energy is then stored in the traction battery, thus charging the traction battery.

[0012] In this process, particularly in or during a first step, the power output of the combustion engine is planned, i.e., determined, based on a route profile determined by the navigation system for a route ahead of, and especially to be traveled by, the hybrid vehicle (such as the aforementioned route), and based on the current state of charge of the traction battery. Specifically, the route profile characterizes the elevation profile of the route, i.e., the altitude to be covered or overcome by the hybrid vehicle. For example, the route profile characterizes the inclines and / or declines to be driven uphill by the hybrid vehicle. Thus, the route profile is, and includes, an elevation profile of the route.Alternatively or additionally, the route profile characterizes, for example, at least one curve of the route that the hybrid vehicle has to drive over or traverse.

[0013] The term "operating phase" of the internal combustion engine refers to the period during which the engine is in its fired operation. During this fired operation, combustion processes occur within the engine, particularly in the combustion chambers. Specifically, within each combustion cycle, one of these combustion processes takes place in the respective combustion chamber. In each combustion process, a fuel-air mixture, also referred to simply as a mixture, is burned, thereby driving and rotating the output shaft. This mixture comprises at least air and a preferably liquid fuel.Thus, during the respective operating phase, the output shaft of the internal combustion engine, for example designed as a crankshaft, rotates around its output shaft axis relative to a housing part of the internal combustion engine. The respective standstill phase is understood to mean that during the respective standstill phase, the internal combustion engine is in a state in which combustion processes cease in the combustion chambers, and in particular in the internal combustion engine as a whole, specifically continuously and without interruption. Specifically, during the respective standstill phase, the output shaft of the internal combustion engine is stationary, so that, for example, during the respective standstill phase, rotation of the output shaft around its output shaft axis and relative to the housing part of the internal combustion engine, specifically continuously and therefore without interruption, does not occur.Put simply, the combustion engine does not run during the respective standstill phase.

[0014] Furthermore, it is provided in a known manner that, during the operating phases, the power output of the combustion engine intended for charging the traction battery is limited depending on the vehicle speed, also referred to as driving speed or speed, particularly that of the hybrid vehicle. In other words, the power output of the combustion engine is limited by a limiting power output of the combustion engine, depending on the speed of the hybrid vehicle. The limiting power output is a function of the speed of the hybrid vehicle. At high speeds of the hybrid vehicle, the limiting power output is equal to the rated power output of the combustion engine. At medium or low speeds of the hybrid vehicle, the limiting power output is lower the lower the speed of the hybrid vehicle.

[0015] Power output characterizes or is the power that can be provided by the combustion engine via the output shaft and is intended or usable for charging the traction battery and / or for directly propelling the hybrid vehicle via the combustion engine. The power output can, for example, be supplied to the charging device to drive the charging device and thus convert the power into electrical energy, which is available or is provided by the charging device and is to be stored or is stored in the traction battery.

[0016] The current state of charge of the traction battery refers to the amount of electrical energy currently stored in the traction battery, and is also known by the acronym SOE (state of energy).

[0017] The method ensures, on the one hand, that a sufficiently large amount of electrical energy is stored in the traction battery, in particular always, to enable the hybrid vehicle to be driven, for example, along the route, in particular along at least one or more sections of the route, by means of the electric motor, by supplying the electric motor with the electrical energy stored in the traction battery, so that the hybrid vehicle can be driven particularly advantageously, in particular particularly dynamically, along the route or along the respective section of the route, for example at a speed desired by a driver of the hybrid vehicle.This prevents, for example, the hybrid vehicle's speed from becoming undesirably low or falling below a desired value. In particular, it ensures that the hybrid vehicle can ascend a gradient, especially one characterized by the road profile, by powering the hybrid vehicle, particularly by means of the electric motor—that is, for example, by the combustion engine and, additionally, by the electric motor, or even by the electric motor alone—so that the hybrid vehicle can ascend the gradient quickly enough without its speed becoming excessively low or undesirably decreasing.On the other hand, operating conditions in which the combustion engine is operated at full power and with an excessively high load, resulting in undesirable noise and / or vibrations, can be avoided. This method thus enables a particularly advantageous noise characteristic, also known as NVH (noise, vibration, and harshness), for the hybrid vehicle.

[0018] In other words, in some driving situations, such as when the hybrid vehicle is traveling at a very low speed, it may be desirable to avoid the combustion engine running or to operate the combustion engine under a low load in order to avoid excessive noise and / or vibrations caused by the combustion engine that could be perceived and possibly found unpleasant by people inside the hybrid vehicle.At the same time, however, it may be desirable to store a suitably large amount of electrical energy in the traction battery, so that it is therefore desirable to charge the traction battery by means of the combustion engine, i.e., by means of its power or power output, in order to then, for example, at least along the aforementioned section of the route, operate the electric motor and thus be able to drive the hybrid vehicle sufficiently strongly by means of the electric motor and, for example, also simultaneously by means of the combustion engine, in order to be able to drive the hybrid vehicle at a sufficiently high vehicle speed along the section, for example, which is designed as an incline, in particular to drive uphill.The power output intended for charging the traction battery and / or for directly propelling the hybrid vehicle via the combustion engine can be set to the vehicle speed-dependent limit in order to avoid excessive noise and vibrations caused by the combustion engine and to charge the traction battery. This allows for advantageous noise characteristics of the hybrid vehicle and ensures that a sufficiently large amount of electrical energy is stored in the traction battery. Consequently, at least along the aforementioned route profile, the hybrid vehicle can be propelled by the electric motor, and in particular by the electric motor and simultaneously by the combustion engine, so that the hybrid vehicle can be driven with sufficient power, i.e., with an advantageously high total power output, at least along this section.For example, a first part of the total power is a first partial power supplied by the electric motor via the drive shaft, and a second part of the total power is, for example, a second partial power supplied by the combustion engine via the output shaft, which together with the first partial power makes up the total power.

[0019] The term "advantageous noise behavior" refers specifically to noise behavior perceptible to the occupants of the hybrid vehicle. However, advantageous noise behavior can also refer to noise behavior perceptible in the external environment of the hybrid vehicle.

[0020] The method thus enables the implementation of a predictive operating strategy for the hybrid vehicle. A primary requirement regarding the state of charge of the traction battery, particularly in the case of a predictive operating strategy, is that if at least one section of the route or route profile is predicted to have a very high power demand for driving the hybrid vehicle along that section—one that exceeds, for example, the power output of the combustion engine alone—a sufficiently large amount of electrical energy must be stored in the traction battery. Otherwise, the hybrid vehicle cannot be driven, or can only be driven insufficiently, along that section and therefore can only travel very slowly.For example, with such a high power demand, a maximum output from the electric motor or the aforementioned total output (the sum of the combustion engine's output and the electric motor's output) is required to enable the hybrid vehicle to travel along the route at a speed desired by the driver. A second requirement regarding the state of charge, particularly in the case of a predictive operating strategy, is that at low vehicle speeds, especially with or without a high power demand, the combustion engine should ideally not be operated, or only with a very low load, due to noise and vibration concerns. At such low vehicle speeds, the combustion engine can therefore hardly be used for charging purposes.This means it can be used to charge the traction battery.

[0021] The method determines, for example, at least or exactly two predictive parameter curves. The first predictive parameter curve is a curve that represents or characterizes the power requirement required, in particular, to propel the hybrid vehicle along the route, either over time or over the distance traveled. The second predictive parameter curve is also referred to as the speed profile, representing the vehicle speed over time or over the distance traveled, particularly given that at low vehicle speeds, 100% of the combustion engine's power should not be utilized.

[0022] Furthermore, a target state of charge value assigned to an end of the route profile is determined in a known manner, particularly in or during the first step of the procedure, and a power profile for the route profile is calculated, wherein, particularly in or during a second step of the procedure, a minimum final state of charge is calculated under the condition that the route profile is traversed with the combustion engine continuously stationary, and wherein, particularly in or during the second step of the procedure, a maximum final state of charge is calculated under the further condition that the route profile is traversed with the combustion engine continuously operating at or with the limit power, which in each case depends on the speed of the hybrid vehicle.This allows for advantageous operation of the hybrid vehicle, as noise and / or vibrations generated by the combustion engine can be avoided or at least minimized, and it can be ensured that a sufficiently large amount of electrical energy is stored in the traction battery, especially at the end of the route profile.

[0023] The end of the route profile refers, for example, to the end of a route or route profile planned by a driver of the hybrid vehicle using the navigation system.

[0024] In order to achieve particularly advantageous operation of the hybrid vehicle, it has proven particularly advantageous if, especially in or during a third step of the procedure, a relative power requirement for the combustion engine is calculated as a quotient of a difference between the target state of charge and the minimum final state of charge and a difference between the maximum final state of charge and the minimum final state of charge.

[0025] Preferably, the second step is performed after the first step. Preferably, the third step is performed after the second step, and thus after the first step.

[0026] The relative power requirement for the internal combustion engine is therefore the relative power that the engine must supply. The relative power requirement is a dimensionless quantity with values ​​between 0 and 1. For example, the relative power requirement could be 0.3, or 30%, which means that the internal combustion engine operates at 30% of its speed-dependent maximum power throughout the entire route.

[0027] Advantageously, the relative power requirement is a parameter used in the feedforward control of a hybrid drive system in a hybrid vehicle. The relative power requirement is advantageously an average power requirement related to the speed-dependent limiting power output. In a control system downstream of the feedforward control of the hybrid drive system, it can be specified that there are sections of the route profile where the combustion engine operates with a higher power output than corresponds to the relative power requirement. Likewise, in the downstream control system, it can be specified that there are sections of the route profile where the combustion engine operates with a lower power output than corresponds to the relative power requirement.

[0028] Therefore, in order to operate the hybrid vehicle particularly advantageously, the invention provides that, particularly in or during a fourth step of the method, the operating phases of the combustion engine are determined, i.e., defined, such that over an entire route profile, or over an entire driving cycle, the combustion engine is operated on average with a power output corresponding to the relative power requirement. The combustion engine is then operated at each point of the route profile on average with a power output calculated by multiplying the limiting power output at that point in the route profile due to the respective vehicle speed by the relative power requirement.

[0029] Preferably, the fourth step of the process is carried out after the third step, particularly after the second step and after the first step. Each step of the process is also referred to as the respective process step. The driving speed is also referred to as the vehicle speed, and vice versa.

[0030] To achieve particularly advantageous operation of the hybrid vehicle, one embodiment of the invention provides that, at vehicle speeds below 30 kilometers per hour (km / h), the combustion engine operates at a maximum of one-quarter of its rated power. By limiting the power output of the combustion engine, undesirable effects caused by the combustion engine, such as unwanted vibrations and / or noise, can be avoided, thus ensuring particularly favorable noise characteristics for the hybrid vehicle. Simultaneously, the power output of the combustion engine can charge the traction battery or prevent its discharge, ensuring that a sufficiently large amount of electrical energy is stored in the traction battery.

[0031] In a further, particularly advantageous embodiment of the invention, the charging device comprises at least one electric motor which can be operated in generator mode and thus as a generator, by means of which the drive power of the combustion engine is converted into electrical energy, or is non-convertible. This enables a particularly advantageous operation of the hybrid vehicle.

[0032] In order to operate the hybrid vehicle particularly advantageously, especially insofar as it can always be ensured that a sufficiently large amount of electrical energy is stored in the traction battery, a further embodiment of the invention provides that the charging device has an additional electric motor, also referred to as a second electric motor, which can be operated in generator mode and thus as a generator, by means of which the drive power of the combustion engine is or is converted into the electrical energy that can be stored or is stored in the traction battery.

[0033] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle, designed as a hybrid vehicle, which is configured to carry out the method according to the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0034] Adjusting the combustion engine's power output for charging the traction battery to the maximum possible load or to the limiting power output depending on the vehicle speed can constitute a limitation of the combustion engine's power output. This limitation is implemented primarily for the comfort of those inside the vehicle, also known as occupants or vehicle passengers. This allows for a particularly high level of driving comfort for the occupants.The target state of charge is, for example, determined either by a person using the vehicle, such as the driver, or the target state of charge is, for example, determined automatically by the procedure, particularly depending on at least one criterion, which includes, for example, the quantity of fuel, particularly liquid, stored in a fuel tank, with which the combustion engine can be operated in powered mode, and / or recuperation possibilities in or during a preceding driving cycle, or similar. In particular, the aforementioned route profile is or characterizes a geographical and / or topographical route of the journey calculated and thus determined, in particular, by means of the navigation system.

[0035] The aforementioned performance profile is, or characterizes, for example, the power requirement for propelling the hybrid vehicle over time or distance, and thus, for example, over the driving route, particularly for the route profile. The maximum and minimum charge end states are respective charge states of the traction battery calculated for one end of the driving route and thus of the route profile, where the end is the destination or coincides with the destination.

[0036] The combustion engine and the at least one electric motor are components of the hybrid drive system by which the hybrid vehicle can be propelled. The hybrid drive system is designed, for example, as a series, parallel, or power-split hybrid drive system. The invention is particularly advantageous in so-called dominant-electric hybrid drive systems.The term "dominant electric" means that the electric drive power for propelling the hybrid vehicle is significantly greater than the combustion engine drive power for propelling the hybrid vehicle. For example, the maximum possible electric drive power (or rated electric drive power) and the maximum possible combustion engine drive power (or rated combustion engine drive power) together result in a total drive power. The electric drive power is greater than 50%, greater than 70%, and less than 100% of the total drive power. The electric range can also be greater, for example, 300 km, than the electric range of today's common plug-in hybrid drive systems, which typically have an electric range of 120 km.In such a predominantly electric system, the combustion engine range may still be greater than the electric range.

[0037] Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing.

[0038] The drawing shows in: Fig. 1 a schematic representation of a hybrid vehicle; Fig. 2 a block diagram to illustrate a procedure for operating the hybrid vehicle; Fig. 3. A diagram to illustrate the procedure; and Fig. 4. Another diagram to further illustrate the procedure.

[0039] In the figures, identical or functionally equivalent elements are provided with the same reference symbols.

[0040] Fig. Figure 1 shows a schematic representation of a motor vehicle, also referred to simply as a vehicle, which is designed as a hybrid vehicle 10. The hybrid vehicle 10 has, in particular, two axles arranged successively in the longitudinal direction of the hybrid vehicle 10, namely a first axle and a second axle. The first axle is in Fig. Figure 1 is shown and labelled 12. Each vehicle axle has, in particular, two wheels. The wheels of axle 12 are labelled 14 and 16. As can be seen from wheels 14 and 16, the wheels of each axle are arranged on opposite sides of the hybrid vehicle 10 in the transverse direction. The transverse direction is illustrated by a double arrow 18, and the longitudinal direction is illustrated by a double arrow 20. As will be explained in more detail below, wheels 14 and 16 are the drive wheels of the hybrid vehicle 10.

[0041] The hybrid vehicle 10 has an internal combustion engine 22, by means of which the drive wheels, and thus the hybrid vehicle 10 as a whole, can be driven. The internal combustion engine 22 has an output shaft, for example designed as a crankshaft, via which initial drive torques can be transmitted to the drive wheels. The respective initial drive torque can be transmitted via a first clutch 24, for example designed as a disconnect clutch, to an axle drive 26 of the vehicle axle 12 and from the axle drive 26 to the drive wheels. The axle drive 26 is a differential gear, also simply referred to as a differential.

[0042] The hybrid vehicle 10 further comprises a traction battery 28 in which electrical energy, in particular electrochemically, is stored. The hybrid vehicle 10 also comprises a charging device 30 by means of which electrical energy can be provided and stored in the traction battery 28. Thus, the traction battery 28 can be charged by means of the charging device 30, and consequently, the amount of electrical energy stored in the traction battery 28 can be increased by means of the charging device 30. In particular, the combustion engine 22 can provide drive power via its output shaft by means of which the drive wheels can be driven and / or, in particular simultaneously, the charging device 30 can be driven.In other words, the drive power provided or available from the internal combustion engine 22 via its output shaft can be supplied to the charging device 30, which is thereby driven and can convert the drive power into electrical energy. This electrical energy can then be supplied by the charging device 30 and stored in the traction battery 28 to charge the traction battery 28. A second coupling 32, designed, for example, as a second disconnect coupling, is provided, through which the charging device 30 can be driven by the internal combustion engine 22, i.e., by the output shaft. Thus, for example, the drive power of the internal combustion engine 22, intended or designed to drive the charging device 30 and thus charge the traction battery 28, can be supplied to the charging device 30 via the coupling 32.It is conceivable that the internal combustion engine 22 can drive the drive wheels via the clutch 24, while the charging device 30 is not driven by the internal combustion engine 22. It is also conceivable that the internal combustion engine 22 can drive the charging device 30 via the clutch 32 and thus charge the traction battery 28, while the drive wheels are not driven by the internal combustion engine 22. Furthermore, it is conceivable that the internal combustion engine 22 drives the drive wheels via the clutch 24 and simultaneously drives the charging device 30 via the clutch 32, so that the internal combustion engine 22, also referred to as the drive engine, drives the drive wheels and simultaneously charges the traction battery 28 via the charging device 30.

[0043] The hybrid vehicle 10 also has at least one electric motor 34. In the case of the Fig. In the embodiment shown in Figure 1, the electric motor 34 is provided in addition to the charging device 30 and is a component distinct from the charging device 30, so that, conversely, the charging device 30 is provided in addition to the electric motor 34. The charging device 30 is, or thus includes, for example, a further electric motor provided in addition to the electric motor 34, which can be operated in generator mode and therefore as a generator. The generator can be driven by the internal combustion engine 22, i.e., by the output shaft, via the coupling 32, whereby the generator can convert the drive power of the internal combustion engine 22 into electrical energy, which can be stored in the traction battery 28.

[0044] The electric motor 34 has a drive shaft 37 which is coupled or can be coupled to the drive wheels for torque transmission. Thus, the drive wheels can be driven by the drive shaft 37 and therefore by the electric motor 34. The electric motor 34 thus functions as a traction motor of the hybrid vehicle 10.

[0045] It is evident that the charging device 30 is designed to charge the traction battery 28 by converting the drive power of the internal combustion engine 22, which is supplied or can be supplied to the charging device 30, in particular via the clutch 32, into electrical energy by means of the charging device 30, which is supplied to the traction battery 28 and stored in the traction battery 28. The hybrid vehicle 10 also features a Fig. 1. Navigation system 39, shown in a particularly schematic way.

[0046] Fig. Figure 2 shows a block diagram, which is used below to explain a procedure for operating the hybrid vehicle 10. In or during a first step S1 of the procedure, also referred to as the first procedure step, operating phases of the combustion engine 22 and standstill phases of the combustion engine 22 are determined, i.e., defined, based on a route profile of a route ahead of the hybrid vehicle 10, also referred to as a route or driving route or route profile, determined by means of the navigation system 39, and based on the current state of charge of the traction battery 28. In particular, the power output of the combustion engine 22 is set to a maximum possible load, in particular to a limit power, of the combustion engine 22 as a function of a vehicle speed of the hybrid vehicle 10.

[0047] In the first step S1, for example, a target state of charge value, designated SOE,T, is defined. The target state of charge value SOE,T is, for example, 40 percent of the maximum amount of electrical energy that can be stored in the traction battery 28. If the current state of charge of the traction battery 28 is therefore 100 percent, the traction battery 28 is fully, i.e., maximally, charged; thus, the maximum amount of electrical energy that can be stored in the traction battery 28 is actually stored in the traction battery 28.The target state of charge is specified, for example, by a person using the hybrid vehicle 10, such as a driver of the hybrid vehicle 10, or the target state of charge is specified, in particular automatically, by the procedure, i.e., for example, by an electronic computing device of the hybrid vehicle 10 carrying out the procedure, depending on certain criteria or parameters.

[0048] The aforementioned route, or route profile, extends from a starting point to a destination, such that the hybrid vehicle 10 can be driven from the starting point to the destination by driving along or retracing the route. The target state of charge is therefore a quantity of electrical energy that, upon reaching the destination, the hybrid vehicle should still have stored, in particular at least or exactly, in the traction battery 28. In the first step S1, the route profile is also defined, and a power profile is calculated from it, which characterizes or illustrates a power requirement, particularly over time. The power requirement is, or characterizes, a power, in particular a total drive power, that is required to drive the hybrid vehicle along the route. The total drive power is to be supplied by the combustion engine 22 and / or by the electric motor 34.

[0049] In or during a second step S2 of the process, also referred to as the second process step, a minimum state of charge, which is also designated SOE,L, is calculated under the condition that the route profile is traversed with the combustion engine continuously stationary, wherein in or during the second step S2 a maximum final state of charge, also designated SOE,H, is calculated under the further condition that the route profile is traversed continuously with the combustion engine operating at or with the maximum possible load, or with the combustion engine operating at or with the limiting power.The minimum state of charge and the maximum state of charge are two calculated end values ​​of the state of charge of the traction battery 28, or two end values ​​calculated for the state of charge of the traction battery 28, wherein the respective end value is calculated, for example, from an initial value, also designated SOE,A, of the current state of charge of the traction battery 28. The initial value is, for example, 60 percent of the maximum amount of electrical energy that can be stored in the traction battery 28. The minimum end value, SOE,L, is a state of charge value that would result if the entire journey of the hybrid vehicle 10 along the route were completed without operation of the combustion engine 22. The minimum end value SOE,L can, for example, be calculated as a negative value.The maximum charge end state SOE,H, also known as the maximum charge end state, is a value representing the state of charge that would result if the hybrid vehicle 10 were to travel the entire route continuously with the combustion engine operating at, at, or near its maximum power output. Specifically, this would result in combustion engine driving with maximum possible charging of the traction battery 28 by additionally driving the generator or charging device 30 via the combustion engine 22, and, if applicable, generator operation of the electric motor 34, insofar as this is possible. The maximum power output of the combustion engine depends on the vehicle speed of the hybrid vehicle 10.

[0050] In or at a third step S3 of the process, also referred to as the third process step, a relative power requirement for the combustion engine 22, also denoted as P,REL, is calculated as a quotient of a difference between the target state of charge SOE,T and the minimum state of charge SOE,L and a difference between the maximum final state of charge SOE,H and the minimum final state of charge SOE,L. Thus, the relative power requirement P,REL is calculated as follows: P,REL=SOE,T−SOE,LSOE,H−SOE,L

[0051] The relative power requirement P,REL is a dimensionless quantity with values ​​between 0 and 1. For example, if SOE,T is 40 percent, SOE,L is 20 percent, and SOE,H is 80 percent, then P,REL is 33.3 percent. This means that the combustion engine 22 operates on average at one-third of its maximum power output, with the maximum power output itself varying depending on the vehicle speed and the road profile. The maximum power output is optimized with regard to noise and / or vibrations of the combustion engine 22 and with regard to rolling noise of the hybrid vehicle 10. At high speeds, also referred to as driving speeds or vehicle speeds, the maximum power output is equal to the rated power of the combustion engine 22. At lower speeds compared to the high speeds, the maximum power output is significantly lower than the rated power output.

[0052] In a fourth step S4 of the process, also referred to as the fourth process step, the operating phases of the combustion engine 22 are determined or defined such that, over an entire driving cycle of the hybrid vehicle 10, the combustion engine 22 is operated continuously with a power output corresponding to the relative power requirement P,REL. In the fourth process step, the power output of the combustion engine 22 is thus determined for each point of the route profile as the product of the relative power requirement P,REL and the speed-dependent limiting power output of the combustion engine at that point.

[0053] Fig. Figure 3 shows a diagram where time, specifically in minutes, is plotted on the abscissa 35. The ordinate 36 of the diagram... Fig. Diagram 3 shows the current state of charge of the traction battery, particularly in the unit %. Figure 38 is a time-dependent progression and a calculated development of the maximum final state of charge SOE,H during continuous operation of the combustion engine 22 at its respective limit power, i.e., taking into account a noise and vibration limit. Figure 40 is a time-dependent progression and a calculated development of the minimum final state of charge SOE,L with the combustion engine 22 continuously deactivated, i.e., switched off. Figure 42 is a time-dependent progression and a calculated development of the current state of charge of the traction battery 28, also expressed as SOE, during operation of the combustion engine 22 at an average of one-third of its limit power. Fig. 3. The previously mentioned example, where the target state of charge SOE,T is 40 percent, or is or was specified as 40 percent. The target state of charge SOE,T corresponds to... Fig. 3 an endpoint of the course 42.

[0054] Fig. Figure 4 shows another diagram, on whose abscissa 44 the vehicle speed of the hybrid vehicle, also referred to as driving speed or speed, is plotted, for example in the unit km / h and in particular with respect to the image planes of Fig. Take 4 from left to right. On the ordinate 46 of the in Fig. The power output of the internal combustion engine 22 is plotted in diagram 4, particularly in kW and especially with respect to the image planes of Fig.4 from bottom to top. A horizontal line 48 illustrates the rated power, i.e., the maximum power of the combustion engine 22. A dashed curve 50 illustrates the limiting power, i.e., the aforementioned noise and vibration limit, whereby curve 50 divides a total operating range GB of the combustion engine 22, located below line 48, into a first operating range B1 and a second operating range B2. In principle, the combustion engine 22 could be operated in the total operating range GB. However, operation in operating range B2, and thus above curve 50, would lead to undesirable noise and / or vibrations that could be perceived and considered unpleasant by persons inside the hybrid vehicle 10.

[0055] The limiting power illustrated by curve 50 is thus determined in the inventive method as a function of the vehicle speed of the hybrid vehicle, such that the limiting power increases with increasing vehicle speed, wherein the limiting power is equal to the rated power of the combustion engine 22 at vehicle speed values ​​equal to or greater than a limiting speed. The limiting speed is advantageously a vehicle speed at which the rolling noise of the hybrid vehicle predominates over the noise of the combustion engine 22.

[0056] It is desirable, intended and possible through the procedure to operate the combustion engine 22 only in operating range B1 and on or along curve 50 and to avoid operating the combustion engine 22 in operating range B2, thereby avoiding unpleasant noises and vibrations perceptible to persons in the interior.At the same time, the method enables the traction battery 28 to be charged via the charging device 30 using the combustion engine 22, thus ensuring a sufficiently large amount of electrical energy stored in the traction battery 28 so that the hybrid vehicle 10 can be driven by the electric motor 34 and, for example, simultaneously by the combustion engine 22, at least along one or more sections of the route, in such a way that the hybrid vehicle 10 can be driven along the section or sections at a sufficiently high speed, as desired, for example, by the driver of the hybrid vehicle 10. This prevents an excessive, undesirable decrease in the vehicle speed of the hybrid vehicle. Reference symbol list 10 Hybrid vehicles 12 vehicle axle 14 vehicle wheel 16 vehicle wheel 18 Double Arrow 20 Double Arrow 22 Internal combustion engine 24 clutch 26 axle gearboxes 28 traction battery 30 Charging device 32 Clutch 34 Electric motor 35 Abscissa 36 ordinates 37 Drive shaft 38 Course 39 Navigation system 40 Course 42 Course 44 Abscissa 46 ordinates 48 Even 50 Curve B1 Operating Area B2 Operating Area GB Total operational area S1 first step S2 second step S3 third step S4 fourth step

Claims

Method for operating a hybrid vehicle (10) in which: - the hybrid vehicle (10) comprises an internal combustion engine (22), a charging device (30), at least one electric motor (34), a traction battery (28), drive wheels (14, 16) and a navigation system (39); - a drive shaft (37) of the electric motor (34) is coupled or can be coupled to the drive wheels (14, 16) in a torque-transmitting manner; - the charging device (30) is configured to charge the traction battery (28) by converting drive power of the internal combustion engine (22) into electrical energy by means of the charging device (30); - power output of the internal combustion engine (22) is planned on the basis of a route profile of an upcoming journey determined by means of the navigation system (39) and on the basis of a current state of charge of the traction battery (28);- during the route profile, the power output of the internal combustion engine (22) is limited to a limit power dependent on a vehicle speed; - a target state of charge value assigned to one end of the route profile is defined, and a power profile for the route profile is calculated, whereby a minimum final state of charge is calculated under the condition that the route profile is traversed with the internal combustion engine (22) continuously stationary, and a maximum final state of charge is calculated under the further condition that the route profile is traversed with the internal combustion engine (22) continuously operating at the limit power; and - a relative power requirement for the internal combustion engine (22) is calculated as a quotient of a difference between the target state of charge value and the minimum final state of charge and a difference between the maximum final state of charge and the minimum final state of charge;characterized in that, throughout the entire route profile, the internal combustion engine (22) is operated on average with a power output corresponding to the relative power requirement. Method according to claim 1, characterized in that during the operating phases at a vehicle speed of less than 30 km / h the internal combustion engine (22) is operated at a maximum of one quarter of its rated power. Method according to claim 1 or 2, characterized in that the charging device (30) has at least one electric motor (34) which is operated in generator mode and thus as a generator by means of which the drive power of the internal combustion engine (22) is converted into electrical energy. Method according to one of the preceding claims, characterized in that the charging device (30) has a further electric motor in addition to the at least one electric motor (34), which is operated in generator mode and thus as a generator, by means of which the drive power of the internal combustion engine (22) is converted into electrical energy. Hybrid vehicle (10) which is designed to carry out a method according to one of the preceding claims.

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