Method for controlling a powertrain in a hybrid vehicle and hybrid vehicle

Abstract

Method for controlling a powertrain (2) in a hybrid vehicle (1), wherein the powertrain (2) has at least one first drive (3) and at least one further drive (4), the method comprising the following steps: - Monitoring (S1) of a power (P) provided for the operation of the first drive (3), - Determine (S2) at least one start parameter (10) depending on the provided power (P), - Evaluate (S3) whether at least one start parameter (10) fulfills a start criterion (20), - Starting (S4) the further drive (4) when the at least one start parameter (10) fulfills the start criterion (20), characterized in that the at least one start parameter (10) is determined as an amount of energy (E) provided for the operation of the first drive (3), wherein the start criterion (20) is fulfilled if the amount of energy (E) provided is greater than or equal to a threshold amount of energy (E S ) is, where the threshold energy quantity (E S ) as value (E X ) a subset of a maximum energy quantity (E MAX ) is determined, whereby the maximum amount of energy (E MAX ) which is used to provide peak power over a maximum time period (T MAX ) corresponds to the necessary amount of energy.

Description

[0001] The invention relates to a method for controlling a powertrain in a hybrid vehicle and to a hybrid vehicle.

[0002] In hybrid vehicles, propulsion can be achieved, for example, purely electrically, in a mixed electric / non-electric mode, or purely non-electrically. A hybrid vehicle can have a primary drive system, such as an electric motor, and a secondary drive system, such as an internal combustion engine. During purely electric propulsion, the electric motor is switched on, while the internal combustion engine may be switched off. However, the internal combustion engine can be started, for example, to relieve the electric motor during mixed propulsion or to provide full propulsion power. It is also known that the internal combustion engine is started, for example, to supply power to an electric drive battery via a generator.

[0003] With the continuous tightening of emissions legislation, it may be necessary to operate an internal combustion engine, e.g. after a cold start, at reduced power, for example at idle, in order to heat up the components of an exhaust aftertreatment system to a permissible operating condition.

[0004] To reduce unnecessary emissions during the operation of an internal combustion engine, or to prevent them from occurring in the first place, various methods for operating hybrid vehicles are known from the state of the art.

[0005] DE 10 2019 127 720 A1 proposes achieving correspondingly low pollutant emissions during cold operation of an internal combustion engine by first powering the hybrid electric vehicle solely through its electric drive motor. Simultaneously, the internal combustion engine is operated – preferably at idle – to warm the exhaust aftertreatment system to a predefined temperature. In a second operating phase, once the exhaust aftertreatment system has reached the required temperature, the hybrid electric vehicle is then powered by the internal combustion engine. The patent also describes how the start of the first operating phase is predictively determined based on the battery's state of charge.

[0006] WO 2020 / 232104 A1 refers generally to hybrid vehicles, in particular to improving the fuel consumption of hybrid vehicles.

[0007] DE 10 2016 106 466 A1 concerns systems and methods for controlling the operation of a power unit in a vehicle with an internal combustion engine.

[0008] The JP 2007 230 468 A concerns a drive control system for a hybrid vehicle with an internal combustion engine and an electric motor.

[0009] Furthermore, it is known that electric motors can heat up as a result of a corresponding load, whereby the heating can lead to undesirable power losses or even damage to the electric motor.

[0010] The technical challenge lies in creating a method for controlling a powertrain in a hybrid vehicle, and a corresponding hybrid vehicle, that further reduces emissions during hybrid vehicle operation. Preferably, the created method and the corresponding hybrid vehicle can further improve aspects of drive power delivery and / or powertrain cooling.

[0011] The solution to the technical problem is provided by the articles with the features of the independent claims. Further advantageous embodiments of the invention are described in the dependent claims.

[0012] Therefore, a method for controlling a powertrain in a hybrid vehicle is proposed, wherein the powertrain has at least one first drive and at least one further drive, and wherein the method comprises the following steps: - Monitoring of power supplied to operate the first drive, - Determine at least one start parameter depending on the provided power, - Evaluate whether at least one start parameter fulfills a start criterion, - Starting the next drive if at least one start parameter meets the start criterion.

[0013] Preferably, the first drive is an electric drive. The first drive can, for example, comprise an electric motor or be designed as such. In particular, an asynchronous motor, a permanent magnet synchronous motor, or a separately or electrically excited synchronous motor is suitable. The first drive can, for example, be powered by a battery. The battery can be part of the first drive and / or the drive train.

[0014] Preferably, the additional drive is a non-electric drive. The additional drive can, for example, comprise or be designed as an internal combustion engine. The internal combustion engine can, for example, be powered by diesel or gasoline. Furthermore, the additional drive can include exhaust aftertreatment for reducing emissions.

[0015] It is of course conceivable that the powertrain in a hybrid vehicle includes further machine elements for converting motion variables or for power and energy conversion, such as a gearbox, a clutch, or a generator.

[0016] Preferably, before starting the second drive, the hybrid vehicle is driven exclusively by the first drive, i.e., the drive power required to move the hybrid vehicle is provided solely by the first drive.

[0017] The power provided can correspond to, or correlate with, the power requested by a user of the hybrid vehicle. Furthermore, the user can adjust the requested power, for example, by varying the pedal travel. Therefore, the power provided can have different values ​​at different times.

[0018] Preferably, the power supplied to operate the first drive is determined using characteristic parameters. For example, the voltage and current applied to the first drive can be recorded as characteristic parameters. From this, a current value of the supplied electrical power can be determined, i.e., a power value for a specific point in time. This point in time can, for example, be the time at which the characteristic parameters were recorded. Furthermore, the point in time can include a timestamp, so that characteristic parameters or determined values ​​can each be assigned to the specific point in time.

[0019] Monitoring refers to determining the power supplied to the operation of the first drive, particularly its current power. Monitoring can, for example, involve the acquisition of key parameters of the first drive, especially through sensors. Naturally, other key parameters of the hybrid vehicle can also be acquired to determine the supplied power. Methods for acquiring key parameters and determining the power of a drive are known to those skilled in the art. The advantageous effect of monitoring is that the power supplied to the operation of the first drive is quantified and can thus be used for further processing within the method.

[0020] Determining the start parameter, or a value of the start parameter, depends on the measured power. In other words, the start parameter is a function of the power supplied to operate the first drive. In the simplest implementation, the start parameter is determined as a value of the supplied power. For this purpose, the measured value of the supplied power, for example, for a specific point in time, can be assigned to the start parameter. However, determining the start parameter based on the supplied power can also be implemented differently, as will be explained below.

[0021] The start criterion must be met to enable the start of the second drive. The start parameter, or a specific value thereof, is used to evaluate the start criterion. In other words, the start criterion can be a condition that the start parameter, or a specific value thereof, must fulfill before the second drive is started. This ensures that the start of the second drive depends on the power supplied by the first drive. For example, it can be ensured that the second drive is only started when deemed necessary based on the available power. This might be the case, for instance, if the first drive needs to be relieved of some of its load for cooling purposes, and at least a portion of its power needs to be supplied by the second drive.

[0022] The start criterion can, for example, stipulate that a specific value of the start parameter is greater than or equal to a threshold. If the threshold is exceeded, for example by the power supplied, the start criterion is met and further drive operation is enabled.

[0023] The threshold value can be predetermined and, for example, correspond to a predetermined continuous power output of the first drive. For electric motors, for instance, it is common for a continuous power output to be known in advance from tests. In this case, the continuous power output corresponds, for example, to the power output of the electric drive that can be provided continuously. If the continuous power output is exceeded, especially over a longer period, above-average heat generation can occur in the electric drive.

[0024] If the start criterion is met, the second drive unit is started. Starting the second drive unit can, of course, involve generating an electrical signal and sending it to the second drive unit. This signal can be generated, in particular, by the hybrid vehicle's control unit or a powertrain control device. Starting the second drive unit can be accomplished, for example, by means of a starter motor. It is also conceivable that starting can be achieved, for example, by means of the first drive unit, perhaps via a suitable mechanical coupling. For instance, the first drive unit can trigger the start of the second drive unit by engaging a corresponding clutch. In this way, a starter motor for starting the second drive unit in the hybrid vehicle can be eliminated, thereby saving weight and costs.

[0025] Preferably, starting the additional drive involves it providing at least a portion of the drive power, for example, by transferring the power to a gearbox. This allows the first drive to operate at a lower power output and thus be relieved of some of its load.

[0026] Preferably, one or more of the described steps of the method according to the invention are executed continuously, particularly iteratively. Specifically, an iteration of the method is executed for each current point in time. Of course, not all steps of the method need to be fully executed in a single iteration; for example, if the start criterion is not met, the iteration is terminated without starting the next drive. If the start criterion is met, the starting of the next drive in the current iteration is enabled and initiated. By iteratively executing the method, a time-lapse history of the provided power or the power values, particularly for the respective current points in time, can then be generated.

[0027] Furthermore, the specific results or values ​​of the process can be stored, for example in a corresponding storage unit that can be part of the hybrid vehicle. Naturally, the process can access results or values ​​from previous iterations.

[0028] The current time point can, as explained previously, include, for example, a timestamp marking the start of an iteration. In this way, a value of the provided performance can be time-stamped for each current time point. Naturally, further steps, results, and / or values ​​of the process can also be time-stamped by the current time point. The time interval between two current time points can be referred to as the process runtime.

[0029] The inventive method delays the start of the secondary drive for as long as possible, thereby avoiding emissions. For this purpose, a start time for the secondary drive is determined by evaluating the start criterion. By considering the power provided by the first drive, it can be ensured that the available power is sufficient, e.g., for propelling the hybrid vehicle, or that the secondary drive is started if the first drive would be overloaded or even damaged, e.g., due to heat generation. The inventive method thus avoids emissions that would result from the unnecessary operation of the secondary drive. Furthermore, the inventive method ensures that the secondary drive is started as soon as this is deemed necessary, e.g., for cooling the first drive.This prevents unwanted overloading of the first drive.

[0030] In another embodiment, the start criterion is determined based on a peak power value of the first drive. The peak power corresponds to the maximum available power during operation of the first drive. That is, the maximum power that can technically be provided for the operation of the first drive. For example, it is common for the peak power of an electric drive to be known or predetermined from tests. For an electric drive, the peak power value is, for example, approximately twice the continuous power output.

[0031] By including peak power, the start of the second drive depends not only on the power supplied by the first drive, but also on the technically available power, namely the peak power, of the first drive. The peak power value, for example, can be assigned as a threshold for the start criterion. The second drive is then started, for example, when the peak power is reached.

[0032] In a further embodiment, the start criterion is determined based on a value representing the time required to preheat the subsequent drive. This time can also be referred to as the preheating time. The preheating time corresponds, in particular, to the time required to preheat the exhaust aftertreatment system of the subsequent drive to a predetermined operating temperature. The value of the preheating time can, for example, be known in advance from tests and thus be predetermined.

[0033] Preferably, preheating is achieved using a heating element. The heating element can be part of the additional drive system. In particular, starting the additional drive system can refer to the heating element being switched on to preheat the additional drive system, thus preheating, for example, the exhaust aftertreatment system. The heating element can, for example, be designed as a heating resistor and be supplied with energy by a battery of the hybrid vehicle. Alternatively or cumulatively, the exhaust aftertreatment system can also be heated after starting the additional drive system by waste heat generated during operation of the additional drive system, such as from the exhaust gases of an internal combustion engine.

[0034] It should be noted that preheating the second drive unit can also be achieved using waste heat from the first. This allows the first drive unit to be cooled while the second is preheated. This increases the energy efficiency of the process and the hybrid vehicle as a whole.

[0035] In a further embodiment, the time required to preheat the secondary drive is determined based on its actual temperature. This temperature can be measured by sensors. The actual temperature refers, in particular, to the temperature of the exhaust aftertreatment system. The preheating time can be shorter, for example, if the actual temperature is higher than a predetermined reference temperature, or longer if it is lower. The reference temperature can, for example, correspond to the ambient temperature. A factor by which the preheating time changes depending on the actual temperature can be predetermined. This allows the system to take into account, when starting the secondary drive, how long it actually needs to be preheated to reach, for example, a desired operating temperature.This helps to avoid unnecessary emissions, especially those caused by preheating the subsequent drive system for too short or too long a time.

[0036] According to the invention, the at least one start parameter is defined as the amount of energy provided for operating the first drive, wherein the start criterion is met if the provided amount of energy is greater than or equal to a threshold energy quantity. This ensures that the amount of energy provided for operating the first drive is limited to the threshold energy quantity before the subsequent drive is started. Thus, for example, it can be ensured that a residual amount of energy is available in the battery as a reserve for emergencies.

[0037] Furthermore, the amount of energy supplied can correlate with, for example, the heat input into the first drive. By determining the amount of energy supplied, the heat input already absorbed can also be taken into account. The second drive can then be started when the first drive needs to be relieved of its load, for example, for cooling purposes.

[0038] The respective energy quantities can be determined, for example, via the voltage values ​​of a battery. However, other methods of determining the energy quantities are also conceivable, as will be explained below.

[0039] In another embodiment, the amount of energy supplied is determined as a time integral of the supplied power from an initial point in time to a current point in time. This time integral can also be referred to as a power integral. The time integral can be calculated, for example, by numerically integrating the values ​​of the supplied power from an initial point in time to a current point in time. For this purpose, the method can access, for example, a time-based profile of the supplied power via the previously described storage unit. The initial point in time could, for example, correspond to the start of operation of the first drive, i.e., the point in time at which a journey with the hybrid vehicle began.

[0040] Furthermore, it is conceivable that the amount of energy supplied is reduced by a predetermined value. For example, the amount of energy supplied can be reduced by the predetermined value if a value of the supplied power determined at an intermediate time is less than a value of the supplied power at a previous time. This allows, for example, the consideration of cooling effects resulting from a reduced power requirement for the first drive. The value for reducing the power integral can, for example, be predetermined from experiments and correlate with a corresponding cooling capacity of the first drive.

[0041] According to the invention, the threshold energy quantity is further determined as a subset of a maximum energy quantity, wherein the maximum energy quantity corresponds to the amount of energy required to provide peak power for a maximum duration. The maximum duration thus corresponds to the period for which the peak power is maximally available to operate the first drive before the first drive would be overloaded, for example, due to heat generation. The maximum duration may, for example, be known or predetermined from experiments. Using the maximum duration and the peak power value, the maximum amount of energy that would be required to operate the first drive at peak power can therefore be determined. The maximum energy quantity can, for example, be determined by time integration.

[0042] The subset of the maximum energy quantity can be determined, for example, using a scaling factor. The scaling factor must be assigned a value between zero and one such that the subset is less than or equal to the maximum energy quantity. This ensures that the threshold energy quantity is at most equal to the maximum energy quantity.

[0043] The subset of the maximum energy quantity can also be determined, for example, as a function of the time required to preheat the subsequent drive. This can be achieved, for instance, by integrating the peak power over a time period corresponding to the difference between the maximum time period and the preheating time period.

[0044] In a further embodiment, the determination of at least one start parameter only occurs when the supplied power is greater than or equal to a predetermined continuous power value of the first drive. This corresponds to a preliminary criterion that precedes the actual start criterion. This advantageously ensures that the start criterion is only evaluated when the supplied power equals or exceeds the continuous power value.

[0045] In a preferred embodiment, the first time point described above is determined when the supplied power is greater than or equal to a threshold value. The threshold value can, in particular, correspond to the continuous power output of the first drive.

[0046] In another embodiment, the second drive only starts once the power supplied to operate the first drive has been reduced by a value corresponding to the power required to start the second drive. For example, the power saved by the first drive, made available by this reduction, could be supplied to a starter motor of the second drive for starting it. This ensures that the reduced power output is available for starting the second drive. After the second drive has started, the power supplied to the first drive can be restored to its original value.

[0047] Preferably, the reduction in power output occurs as a continuous transition function. This means the power is reduced in uniform steps until the desired reduction value is reached. This ensures that the drive power is not reduced abruptly, thus increasing driving comfort for the user. Naturally, the power output can also be increased again as a continuous transition function once the drive has been restarted.

[0048] A further proposal is a hybrid vehicle with a powertrain, wherein the powertrain has at least one first drive and at least one further drive, wherein the hybrid vehicle further comprises a device for controlling the powertrain, wherein the device is configured to execute a method according to an embodiment described in this disclosure.

[0049] The powertrain control unit can be designed as a microcontroller or include one. The unit can be connected to the first and second drives via signaling. Naturally, the unit can also be connected to other machine elements of the hybrid vehicle via signaling.

[0050] In particular, the device can receive and process the signals necessary for carrying out the method according to the invention, and generate and output signals, especially at least one signal for starting the further drive. The device can also include or form the storage unit described above, or be connected to it via signal technology.

[0051] The proposed hybrid vehicle can be used to carry out a method that can achieve one or all of the technical effects mentioned in this disclosure. The advantages resulting from these technical effects also apply accordingly to the hybrid vehicle according to the invention.

[0052] A further proposal is a computer program product comprising a computer program, wherein the computer program includes software means for executing one, several, or all steps of the method according to the invention in one of the embodiments described in this disclosure, in particular for executing the monitoring, determining, evaluating, and starting. The computer program can be executed by or in a computer or by the described device for controlling the drive train.

[0053] This means that the method according to the invention is, for example, a computer-implemented method. For instance, all steps or only some of the steps (i.e., fewer than the total number of steps) of the method according to the invention can be performed by a computer or the device. One embodiment of the computer-implemented method is the use of the computer or the device to carry out the method according to the invention.

[0054] The computer program product advantageously enables the implementation of a method according to the invention in accordance with one of the embodiments described in this disclosure, for which technical advantages have been previously described.

[0055] The invention is explained in more detail using exemplary embodiments. The figures show: Fig. 1 a schematic representation of a first embodiment of a hybrid vehicle according to the invention, Fig. 2 a flowchart of a first embodiment according to the invention of a method for controlling a powertrain in a hybrid vehicle, Fig. 3 a first pair of diagrams for determining a start parameter in a first embodiment of the method according to the invention, Fig. 4 a schematic representation of a further embodiment of a hybrid vehicle according to the invention, Fig. 5 a flowchart of a further embodiment according to the invention of a method for controlling a powertrain in a hybrid vehicle and Fig. 6 another pair of diagrams for determining a start parameter in a further embodiment of the method according to the invention.

[0056] In the following, identical reference symbols denote elements with the same or similar technical characteristics.

[0057] Fig. Figure 1 shows a schematic representation of an embodiment of a hybrid vehicle 1 according to the invention. The hybrid vehicle 1 comprises a powertrain 2. In the illustrated embodiment, the powertrain 2 has a first drive 3, which is designed as an electric motor. A battery 15 supplies the first drive 3 and other electrical or electronic components with electrical energy.

[0058] Furthermore, the drive train 2 includes another drive 4, comprising an internal combustion engine 4-1 and an exhaust aftertreatment system 4-2. An associated fuel tank for the internal combustion engine 4-1 is not shown.

[0059] The drive train 2 further comprises machine elements such as a gearbox 13, which transmits the power from the first drive 3 and / or from the second drive 4 to an axle or the corresponding wheels of the hybrid vehicle 1. Additional machine elements include a clutch 14 between the second drive 4 and the gearbox 13, so that the power generated by the second drive 4 can be used directly for propulsion. After the second drive 4 has been started, the first drive 3 can, of course, also be used as a generator, and the energy provided by the second drive 4 can be converted into electrical energy for charging the battery 15.

[0060] Furthermore, the hybrid vehicle 1 includes a device 30 for controlling the powertrain 2. The device 30 has a microcontroller and, in the illustrated embodiment, is configured to control the Fig. The two methods shown are for controlling the drive train 2. Signals for executing the method can be received by the device 30 via appropriate lines (in Fig. (1 shown as simple lines) receive and / or output. A line that can transmit a signal S to start the internal combustion engine 4-1 from the device 30 to the further drive 4 is also shown.

[0061] Fig. Figure 2 shows a flowchart of an embodiment of a method according to the invention for controlling a powertrain 2 in a hybrid vehicle 1. The method comprises several steps S1, S2, S3, and S4, which are executed iteratively. An iteration of the method begins with a first step S1. Each step S1, S2, S3, S4 of the method refers within a respective iteration to a point in time, which is referred to as the actual time T2. In other words, the actual time T2 corresponds to a timestamp at the beginning of the execution time of an iteration of the method. Once an iteration of the method is completed, a new iteration begins with a new actual time T2. The method begins, for example, at the beginning of a journey. The time of the beginning of a journey can be designated T0 (see Figure 2). Fig. 3).

[0062] In a first step S1, the power P supplied to operate the first drive 2 is monitored. For this purpose, the voltage U and current I applied to the first drive 2 are recorded at the actual time T2, e.g., using appropriate sensors. The values ​​of voltage U and current I are input values ​​to the procedure, which are processed in a numerical operation 17 to obtain a value for the supplied power P at the actual time T2.

[0063] In a further step S2, it is checked whether the determined value of the provided power P is greater than or equal to a predetermined value P. D a continuous power output of the first drive 2. This check is also referred to as pre-criterion 19. If pre-criterion 19 is not met, N, i.e., P < P DThe iteration for the current time point T2 is terminated, and a new iteration for a subsequent current time point T2 is started (represented by the arrow leading to step S1). This can be repeated until the pre-criterion 19 is satisfied. If pre-criterion 19 is satisfied, the current time point T2 for which pre-criterion 19 was satisfied is determined as the first time point T1. The first time point T1 serves as the reference for determining an energy quantity E.

[0064] In the next step S2, a numerical integration 18 is performed, whereby the energy quantity E is determined as a time integral of the supplied power P from the first time T1 to the actual time T2. The integral thus determined can also be called the power integral. The value of the power integral corresponds to the amount of energy used to generate a power above the value P. Dto provide the continuous power output over the period T1, T2. This amount of energy E can, for example, correlate with a heat input into the first drive 3, whereby the heat input should, for example, not exceed a corresponding limit value.

[0065] It should be noted that the resulting value of the integral in the first iteration, after fulfilling pre-criterion 19, is of course machine-precisely zero, since the first time point T1 corresponds to the actual time point T2 of this iteration. In subsequent iterations of the procedure, the value of the power integral continues to increase if pre-criterion 19 is also fulfilled by the subsequent values ​​of the supplied power P. The corresponding values ​​of the power P from the previous iterations can be retrieved by the procedure from a memory unit (not shown) for the purpose of further numerical integration 18.

[0066] The further aim of step S2 is to determine a start parameter 10. Following the numerical integration 18, the value of the determined energy quantity E is assigned to the start parameter 10 in a numerical operation 17.

[0067] In a further step S3, the start criterion 20 is evaluated using the start parameter 10. To fulfill the start criterion 20, the current value of the start parameter 10 must be greater than or equal to a threshold energy quantity E. S be. The threshold energy quantity E S can be determined, for example, in such a way that the previously mentioned limit value for a corresponding heat input into the first drive 3 is not exceeded.

[0068] In Fig. 2 becomes the threshold energy quantity E S In the next step, S3 is determined as follows: A predetermined value P MAXthe peak power of the first drive 3 and a value of an associated maximum duration T MAX The scaling factor X and the input values ​​to the procedure are called P. MAX The peak power corresponds to the maximum power value that can theoretically be achieved using the first drive 3. The maximum duration T MAX corresponds to the duration over which the peak power P MAX Theoretically, this can be provided without the previously described heat input. The scaling factor X can, for example, correspond to a predetermined safety factor by which the maximum time duration T is scaled.

[0069] Using numerical integration 18, a subset E can be obtained from these input values. X a maximum amount of energy E MAX determine the maximum energy amount E MAX the one used to provide peak power P MAX over the predetermined maximum time period Tmax The necessary amount of energy corresponds to the subset E. X corresponds to the maximum energy quantity E scaled by the scaling factor X MAX .

[0070] In a further numerical operation 17, the value of the subset Ex is assigned the value of the threshold energy quantity E. S assigned this value of the threshold energy quantity E S now forms the limit value for the current value of the start parameter 10 in the respective iteration of the procedure (see Fig. 3).

[0071] If the start criterion 20 is not met by the current value of the start parameter 10 N, i.e., 10 < E S If the value of the start parameter 10 is greater than or equal to the threshold energy quantity E, the iteration ends at this point and a new iteration begins (represented by the arrow leading to step S1). S, so the start criterion 20 Y is fulfilled and the starting of the further drive 4 is enabled.

[0072] In a further step S4, a signal S to start the further drive 4 is then generated by the device 30 and output to it (see Fig. 1) By starting the additional drive 4, the first drive 3 can then be relieved accordingly, e.g. by providing at least a portion of the power required to move the hybrid vehicle 1 by the additional drive 4.

[0073] The method thus advantageously results in the additional drive 4 only being started when this appears necessary to relieve the load on the first drive 3. In this way, unnecessary emissions from the additional drive 4 can be avoided.

[0074] Fig. Figure 3 shows a first pair of diagrams for determining a start parameter 10 according to the first embodiment of the method according to the invention (see Figure 3). Fig. 2).

[0075] The upper diagram shows an idealized curve of the supplied power P from time T0 of the start of a journey to an actual time T2. Furthermore, a theoretical time T3 is shown, which corresponds to the end time of the maximum duration T. MAX corresponds to the maximum time duration T. MAX It may, for example, be predetermined and has been explained previously.

[0076] At the start of the journey, a constant value is provided as power P for the operation of the first drive 3, according to the diagram above, which corresponds to a value P D corresponds to the continuous power output of the first drive 3. Waste heat generated during the provision of this value P DThe power generated can be transported away, for example, via a cooling device (not shown) of the hybrid vehicle 1, without heat accumulation in the first drive 3.

[0077] At a first point in time T1, the supplied power P jumps from the value P D the continuous power output to a value P MAX for example, because the user of hybrid vehicle 1 requests increased drive power. The value P MAX This corresponds to the peak power of the first drive 3. Referring to Fig. 2. Therefore, at time T1, the previously explained pre-criterion 19 is fulfilled and the amount of energy provided E is determined by means of numerical integration 18 (see step S3 in Fig. 2 and lower diagram in Fig. 3).

[0078] Further referring to Fig. 2 can be derived from the maximum duration T MAXand a subset E with, for example, a predetermined scaling factor X X a maximum amount of energy E MAX to be determined (see step S3 in Fig. 2) In the upper diagram, the value corresponds to the subset E X The area under the curve of the supplied power P between times T1 and T2 is indicated by hatching. The subset Ex is then referred to as the threshold energy quantity E. S used in starting criterion 20 (see step S3 in Fig. 2 and lower diagram in Fig. 3).

[0079] The lower diagram shows a corresponding progression of the values ​​of the start parameter 10. In this case, due to the constant power value P, the following results: MAXThe upper diagram shows a linear progression of the starting parameter 10, or the amount of energy supplied, E. However, it is also conceivable that a non-linear progression results, for example, if the supplied power P exhibits a non-constant profile.

[0080] Fig. Figure 4 shows a schematic representation of another embodiment of a hybrid vehicle 1 according to the invention. The Fig. The hybrid vehicle shown in section 4, unlike the one in [section / document], has... Fig. In the embodiment shown in Figure 1, a further drive 4 is provided, comprising an internal combustion engine 4-1, an exhaust aftertreatment system 4-2, and a heating element 4-3. The heating element 4-3 is switched on as a result of the signal S generated in step S4. This corresponds to starting the further drive 4 and serves to preheat the exhaust aftertreatment system 4-2. The internal combustion engine 4-1 can then be started when the exhaust aftertreatment system 4-2 has been preheated to a corresponding temperature.

[0081] Fig. Figure 5 shows a flowchart of a further embodiment of a method according to the invention for controlling a powertrain 2 in a hybrid vehicle 1. The in Fig. The 4 methods shown, compared to the one in Fig. In the embodiment shown in section 2, a modified step S3 is introduced.

[0082] In the Fig. In step S3, shown in section 5, the time interval used to determine the threshold energy quantity 21 is determined differently. In the illustrated embodiment, the time interval used for numerical integration 18 is determined as the difference between the maximum time duration T. MAX and a preheating time T H , which are used for preheating the in Fig. The exhaust aftertreatment system 4-2 shown in section 4 is required. The value T H The preheating time can be predetermined or, for example, determined depending on the actual temperature of the exhaust gas aftertreatment system 4-2. Numerical integration 18 thus yields a subset E X a maximum amount of energy E MAX certainly.

[0083] In a further numerical operation 17, the value of the subset E is X the value of the threshold energy quantity E S assigned this value of the threshold energy quantity E Snow forms the limit value for the current value of the start parameter 10 in the respective iteration of the procedure (see Fig. 6).

[0084] Fig. Figure 6 shows another pair of diagrams for determining a start parameter 10 according to a further embodiment of the method according to the invention. In contrast to the one in Fig. The first pair of diagrams shown in 3 refers to the one in Fig. The 6 pairs of diagrams shown are based on the information in Fig. 4 embodiment of the method according to the invention (see below). Fig. 4).

[0085] In Fig. 6 shows that the subset Ex of the maximum energy quantity E MAX - in contrast to the one in Fig. 2 and Fig. 3. Explained embodiment - also using the difference between the maximum time duration T MAX and a value T H the preheating time can be determined (see step S3 in Fig. 4). Reference symbol list 1 hybrid vehicle 2 Powertrain 3 first drive 4 additional drives 4-1 Internal combustion engine 4-2 Exhaust aftertreatment 4-3 Heating element 10 starting parameters 13 gearboxes 14 Clutch 15 batteries 17 numerical operations 18 numerical integration 19 Pre-criteria 20 Starting criteria 30 Device for controlling the drive train E amount of energy provided E MAX Maximum energy amount E S Threshold energy quantity E X Value of a subset of a maximum energy quantity I Current intensity P provided power P MAX Value of a predetermined peak power of the first drive P D Value of a predetermined continuous power output of the first drive N criterion not met S signal to start further drive S1 first step S2 further step S3 further step S4 further step U voltage T Maximum duration T0 Time at the start of the journey T1 first time point T2 Actual Time T3 End time of the maximum duration T MAX Maximum duration T H Preheating time X scaling factor Y criterion fulfilled

Claims

[1] Method for controlling a powertrain (2) in a hybrid vehicle (1), wherein the powertrain (2) has at least one first drive (3) and at least one further drive (4), the method comprising the following steps: - Monitoring (S1) of a power (P) provided for the operation of the first drive (3), - Determine (S2) at least one start parameter (10) depending on the provided power (P), - Evaluate (S3) whether at least one start parameter (10) fulfills a start criterion (20), - Starting (S4) the further drive (4) if at least one start parameter (10) meets the start criterion (20), characterized by, that the at least one start parameter (10) is determined as an amount of energy (E) provided for the operation of the first drive (3), wherein the start criterion (20) is satisfied if the amount of energy (E) provided is greater than or equal to a threshold amount of energy (E S ) is, where the threshold energy quantity (E S ) as value (E X ) a subset of a maximum energy quantity (E MAX ) is determined, whereby the maximum amount of energy (E MAX ) which is used to provide peak power over a maximum time period (T MAX ) corresponds to the necessary amount of energy. [2] Method according to claim 1, characterized by , that the starting criterion (20) depends on a value (P MAX ) a peak power of the first drive (3) is determined. [3] Method according to claim 1 or 2, characterized by , that the start criterion (20) depends on a value (T H) a time period necessary for preheating the further drive (4). [4] Method according to claim 3, characterized by , that the value (T H ) the time required to preheat the further drive (4) is determined as a function of the actual temperature of the further drive (4). [5] Method according to any of the preceding claims , characterized by , that the amount of energy provided (E) is determined as a time integral over the power provided (P) from a first time point (T1) to an actual time point (T2). [6] Method according to any of the preceding claims, characterized by , that the determination of at least one start parameter (10) only takes place when the provided power (P) is greater than or equal to a value (P D ) a predetermined continuous power output of the first drive (3). [7] Method according to any of the preceding claims, characterized by, that the starting of the further drive (20) only takes place when the power (P) provided for the operation of the first drive (3) has been reduced by a value corresponding to a power required to start the further drive (4). [8] Hybrid vehicle (1) with a powertrain (2), wherein the powertrain (2) has at least one first drive (3) and at least one further drive (4), wherein the hybrid vehicle (1) further comprises a device (30) for controlling the powertrain (2), wherein the device (30) is configured to perform a method according to any one of claims 1 to 7.

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