DE102022111312A1 - Dedicated hybrid powertrain and method for controlling the same - Google Patents

Abstract

The invention relates to a dedicated hybrid drive train (1) of a motor vehicle and a method for controlling it with a drive unit (4) formed from a first electric machine (EM1) and an internal combustion engine (ICE) and a second electric machine (EM2), the drive unit (4 ) can be connected by means of a first separating clutch (C1) and the second electric machine (EM2) by means of a second separating clutch (C2) to a transmission (8) operatively connected to drive wheels and an accumulator (17) drives the electric machines (EM1, EM2) and from them can be recharged generatorically. In order to improve the performance and effectiveness of the hybrid drive train (1), the transmission (8) has two thermal gear stages (11, 12) that can be switched alternatively using the first separating clutch (C1) and one electrical gear stage (11, 12) that can be switched using the second separating clutch (C2). 9), wherein the hybrid drive train (1) is controlled depending on a driver's desired torque, a charge state of the accumulator (17) and the driving speed of the motor vehicle.

Description

The invention relates to a dedicated hybrid drive train of a motor vehicle and a method for controlling it with a drive unit formed from a first electric machine and an internal combustion engine and a second electric machine, the drive unit being operatively connected to drive wheels by means of a first separating clutch and the second electric machine by means of a second separating clutch Gears can be connected and an accumulator drives the electric machines and can be charged by them as generators.

The invention relates to a dedicated hybrid drive train and a method for controlling a dedicated hybrid drive train of a motor vehicle with a drive unit formed from a first electric machine and an internal combustion engine and a second electric machine, wherein the drive unit by means of a first separating clutch and the second electric machine by means of a second separating clutch with a Drive wheels which are operatively connected and have at least one gear ratio can be connected and an accumulator drives the electric machines and can be charged by them as generators.

Hybrid drive trains with an internal combustion engine and two electric machines are, for example, from the publication DE 10 2018 103 245 A1 known. Disclosed is a drive unit for a hybrid drive train of a motor vehicle with an internal combustion engine, a first electric machine, a second electric machine arranged coaxially with respect to its rotor to an axis of rotation of a rotor of the first electric machine, a first transmission stage, arranged between a rotationally fixed or coupled to an output shaft of the internal combustion engine Drive component and a drive shaft of the first electric machine and / or the electric machine, as well as a transmission subunit, via which the drive shaft of the respective electric machine is coupled or can be coupled to wheel drive shafts. Also from the printed matter US 2016/0218584 A1 , DE 11 2015 006 071 T5 , EP 331 372 A1 and WO 2019/101 264 A1 Various transmission structures of a hybrid drive train are known.

The unpublished patent application DE 10 2021 111 350.4 the applicant, which is hereby incorporated in its entirety, further shows embodiments of hybrid drive trains with a drive unit consisting of an internal combustion engine and a first electric machine and a second electric machine, the drive unit and the second electric machine being connectable by means of a separating clutch to a transmission which is operatively connected to drive wheels and has at least one gear ratio are.

Such hybrid drive trains are referred to as dedicated hybrid drive trains or hybrid transmissions (“Dedicated Hybrid Transmissions”, DHT). In these cases, the mechanical transmission part is simplified, for example by eliminating the reverse gear, and instead at least one electric machine integrated into the transmission is used to display the full range of functions. Dedicated hybrid transmissions can emerge from well-known transmission concepts, i.e. dual clutch transmissions, converter planetary transmissions, continuously variable transmissions (CVT) or automated manual transmissions. The electric machine becomes part of the transmission and can be connected to different transmission shafts. In addition to the parallel and/or serial hybrid modes, one or more power-split operating states can also be created in combination with a planetary gear.

A serial operating state of the hybrid drive train is understood to mean that the internal combustion engine has no mechanical/torque-transmitting connection to the drive axle/output shaft. The internal combustion engine drives the first electric machine, which functions primarily as a generator, which in turn supplies the main second electric machine, which functions as a traction motor/drive motor, with electricity or charges a battery. The drive axle is driven by the second electric machine. A parallel hybrid mode is understood to mean that the internal combustion engine has a mechanical/torque-transmitting connection to the drive axle/output shaft. The second electric machine can run empty, boost or recuperate.

Known methods for controlling dedicated hybrid drive trains provide exclusively for the serial operating state, particularly during start-up processes of the motor vehicle, whereby the accumulator can be quickly discharged during repeated starts at low driving speeds. As a result of the need to charge the accumulator using the internal combustion engine, even during idle times, acoustic stress can occur for the occupants of the motor vehicle. The object of the invention is the development of a dedicated hybrid drive train and a method for operating a dedicated hybrid drive train. In particular, the object of the invention is to operate a motor vehicle with a dedicated hybrid drive train with high performance and economically and to ensure that the battery is charged and maintained.

The task is solved by the subjects of claims 1 and 3. The claims dependent on claims 1 and 3 represent advantageous embodiments of the subject matter of claim 1 and claim 3 respectively.

The proposed dedicated hybrid drive train has two drive sources, namely a drive unit with an internal combustion engine and a first electric machine connected to it in terms of drive, and a second electric machine, each of which can be connected to drive wheels by means of a separating clutch, for example a positive clutch.

In addition to a differential, a gearbox is arranged between the drive wheels and has a plurality of gear ratios. In particular, two so-called thermal gear stages with different ratios are provided, which can be switched alternatively by means of a first separating clutch and thus connect the drive wheels to the drive unit. The gear stages are adapted to the usable speed range of the internal combustion engine, so that the internal combustion engine or the drive unit can be used to drive the motor vehicle even at low driving speeds and at high driving speeds without the interposition of a torque-leveling friction clutch. The separating clutch, which can be designed, for example, as a clutch with a switching sleeve, sliding sleeve and synchronizing rings, contains three switching positions, each with a switched connection of a thermal transmission stage between one with an output shaft of the drive shaft and a transmission output shaft of the transmission and a neutral position in which the drive unit of is disconnected from the drive wheels.

A further, so-called electric gear stage of the transmission is used to adapt the speed range of the second electric machine, which can be integrated into the transmission, for example. The separating clutch, for example a clutch with a shift sleeve, sliding sleeve and synchronizing rings, has two switching positions, in one of which the rotor of the second electric machine is connected to the transmission output shaft and a neutral position in which the second electric machine is decoupled from the drive wheels. The individual gear stages are shifted, for example, by means of the shift forks and corresponding shift rails, shift shafts, shift drums and/or the like by means of an automated shift actuator, which is operated, for example, hydraulically or electromechanically. This switching actuator can, for example, additionally operate a parking lock of the motor vehicle. Alternatively, at least one separating clutch can be designed as a claw clutch. The electrical energy to operate the electric machines is stored in an accumulator. One or both electric machines can be operated as a generator to charge the accumulator. Here, the first electric machine can be driven by the internal combustion engine, and the second electric machine can generate electrical energy from recuperation.

Preferably, in order to increase the performance of the motor vehicle, for example to increase its acceleration, for example in the range from 0 to 100 km/h, to increase its agility and/or the like, an accumulator, for example a lithium-ion accumulator, is provided for a dedicated hybrid drive train has a comparatively high battery discharge power of over 40 kW, preferably greater than 60 kW and particularly preferably greater than or equal to 100 kW. It has been shown that the advantages of energy gain and energy efficiency of such an accumulator exceed the disadvantages of the higher weight.

The proposed method is used to control the proposed dedicated hybrid powertrain. In the hybrid drive train, the internal combustion engine, the electric machines and the separating clutches are basically controlled depending on the driver's desired torque, which the driver specifies, for example in the form of an accelerator pedal, a vehicle speed and the charge status of the accumulator. Further parameters such as the condition of the road such as its gradient and curves, road conditions in summer and winter operation, adhesion of the wheels to the road and/or the like, braking effect, outside temperature and/or vehicle components, lighting conditions, traffic volume can be included in a list that is not necessarily exhaustive in full or in part are incorporated into the control of the hybrid powertrain.

It has been shown advantageously that the use of two thermal gear stages with a small and a large gear ratio enables the internal combustion engine to be switched on much earlier in special driving situations, without having to use the slip effect of a friction clutch and a separate switching of the gear stages and a neutral position using a single form-fitting coupling. For example, in driving situations in which it is often necessary to start off purely electrically in series operation, an increasing discharge of the accumulator can occur if the internal combustion engine is not sufficiently charged or if the charge is high Noise pollution from the internal combustion engine when the accumulator is required to be recharged due to the large gear ratio of the first gear stage to slow, the internal combustion engine can be switched on much earlier and can be driven in parallel operation with the support of the internal combustion engine in the drive of the motor vehicle. The rechargeable battery can optionally be carried out at lower speeds of the internal combustion engine and thus with less noise. In the second gear stage with a much smaller gear ratio to slow or, depending on the subsequent gear ratio, up to the drive wheels with a gear ratio to fast, it is still possible to drive at high driving speeds with the speed of the internal combustion engine in a moderate range with the support of the drive unit or with the internal combustion engine alone. In order to implement economical and, if necessary, agile operation of the motor vehicle with the proposed hybrid drive train with two thermal transmission stages, various operating modes are controlled depending on the driver's desired torque, the charge status of the accumulator and the driving speed. In a first operating mode, the motor vehicle is driven in series, in which the second electric machine is driven purely electrically and the internal combustion engine charges the accumulator using the first, generator-operated electric machine. For example, a serial drive occurs when driving with the accumulator not fully charged and at lower travel speeds. The second electric machine is operated in its most energetically efficient speed range. If rapid, moderate acceleration is to take place, the second electric machine can be operated in so-called boost mode by briefly operating it, for example during an overtaking process, at a higher speed, outside the most favorable speed of the rotor, and/or at a higher nominal power.

In a second operating mode, the motor vehicle is driven in parallel by driving by means of the drive unit, selecting the first thermal gear stage and the second electric machine. Here, at least part of the power of the internal combustion engine is made available to drive the motor vehicle. Another part of the power can be made available for charging the accumulator by operating the first electric machine as a generator.

In a third operating mode, the motor vehicle is driven in parallel by means of the drive unit by selecting the second thermal transmission stage and the second electric machine. The first electric machine can also be driven at least temporarily, especially when the battery is fully charged, and can support the drive of the motor vehicle, for example when the driver requires high acceleration or at high driving speeds.

In a fourth operating mode, an exclusive drive by means of the internal combustion engine via the second gear ratio is provided.

In a so-called boost operation, for example when high accelerations are requested by the driver, in the individual operating modes with the first and/or second electric machine operated in terms of drive and motor, operation of these electric machines can be provided for a short time above their nominal power.

In a fifth operating mode when the motor vehicle is at a standstill, a parking lock can be engaged. The parking lock can be actuated with a switching actuator to switch the transmission stages and can be controlled using software that controls the control of the hybrid powertrain. In the fifth operating mode, the internal combustion engine can be shut down or, if necessary, started depending on the charge status of the accumulator or by the driver in order to charge it while the motor vehicle is at a standstill using the first electric machine driven by the internal combustion engine as a generator.

In a sixth operating mode, kinetic energy of the motor vehicle can be recuperated by charging the accumulator using the second electric machine driven as a generator by the drive wheels when the drive unit is decoupled from the transmission and the motor vehicle is moving.

In a seventh operating mode, the motor vehicle can be driven backwards in serial or purely electrical operation by reversing the direction of rotation of the second electric machine, so that a mechanically designed reverse gear is dispensed with and production costs and manufacturing effort can be saved.

It is understood that, particularly in noise-calmed inner city areas and the like, in an eighth operating mode, the motor vehicle can be driven purely electrically using the second electric machine with the drive unit decoupled and the internal combustion engine stopped when the battery is sufficiently charged.

The different operating modes are applied depending on the charge status of the battery. For this purpose, the charge state is divided into several charge state ranges, inner half of which, in turn, different operating modes are set depending on the driver's desired torque and the current driving speed. For example, the state of charge is divided into areas in which normal operation of the hybrid drive train is not intended, for example at a very low state of charge of, for example, less than 10% to 20% remaining charge of the maximum charging capacity, or a charge of greater than 80% of the maximum charging capacity. These limit charging states are preferably only set in emergency situations when there is a risk of the battery breaking down or being damaged due to accidentally charging too much. In between, for example, three generally usable areas of the state of charge can be distinguished, for example a high state of charge with a charging capacity of 41% to 80% of the maximum charge, a medium state of charge with 26% to 40% of the maximum charge and a low state of charge with 11% to 25% of the Maximum charge of 100%. It is understood that the limits of the charge states, as well as the current capacity, temperature and/or other variables that permanently or acutely influence the quality of the battery, can be adapted to the motor vehicle depending on the situation and can be continuously adapted, for example depending on the age, the expected lifespan and/or the like can be trained. In the individual areas, the modes are set depending on the driver's desired torque, for example, in which, for example, when the driver's desired torque is currently high, the electric machine currently used for the drive or both electric machines and possibly the internal combustion engine are operated in a boost mode, that is, briefly in a power range higher than the rated power can be operated. Alternatively, the mode can be changed and, for example, an electric machine and/or the internal combustion engine can be switched on. For example, a typical, adapted driver's desired torque and its development over time can be taken into account. In the individual areas of the state of charge, the operating modes are also set depending on the driving speed of the motor vehicle, for example to compensate for the increasing driving resistance as the driving speed increases. Due to the lack of a friction clutch between the internal combustion engine and the drive wheels, only the first, seventh and eighth operating modes are used for starting and reversing; operating modes one and seven are, if necessary, boosted with the second electric machine. When the synchronous speed between the smallest usable speed of the internal combustion engine and the transmission output shaft in the first thermal transmission stage is reached, the second operating mode can be switched and driven from a predetermined driving speed for parallel operation of the hybrid drive train. At high driving speeds, for example, it is possible to switch to the third operating mode with the second thermal gear stage.

• 1 einen dedizierten Hybridantriebsstrang in schematischer Darstellung,
• 2 eine Tabelle verschiedener Betriebsmodi des Hybridantriebsstrangs der 1 und dessen zugehörige Beschaltung,
• 3 ein Schaltdiagramm eines Schaltaktors bei einem Fahrvorgang eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 2,
• 4 ein Diagramm des Radmoments über die Fahrgeschwindigkeit eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 1 bei niedrigem Ladezustand des Akkumulators,
• 5 ein Diagramm des Radmoments über die Fahrgeschwindigkeit eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 1 bei mittlerem Ladezustand des Akkumulators,
• 6 ein Diagramm des Radmoments über die Fahrgeschwindigkeit eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 1 bei hohem Ladezustand des Akkumulators,
• 7 ein Diagramm des Radmoments über die Fahrgeschwindigkeit eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 1 mit einem Akkumulator mit niedriger Entladeleistung und
• 8 ein Diagramm des Radmoments über die Fahrgeschwindigkeit eines Kraftfahrzeugs mit dem Hybridantriebsstrang der 1 mit einem Akkumulator mit hoher Entladeleistung.

The invention is based on the in the 1 until 8th illustrated embodiment explained in more detail. These show:

• 1 a dedicated hybrid powertrain in a schematic representation,
• 2 a table of different operating modes of the hybrid powertrain 1 and its associated circuitry,
• 3 a circuit diagram of a switching actuator during a driving process of a motor vehicle with the hybrid drive train 2 ,
• 4 a diagram of the wheel torque versus the driving speed of a motor vehicle with the hybrid drive train 1 when the battery charge level is low,
• 5 a diagram of the wheel torque versus the driving speed of a motor vehicle with the hybrid drive train 1 with a medium charge level of the battery,
• 6 a diagram of the wheel torque versus the driving speed of a motor vehicle with the hybrid drive train 1 when the battery charge level is high,
• 7 a diagram of the wheel torque versus the driving speed of a motor vehicle with the hybrid drive train 1 with a battery with low discharge power and
• 8th a diagram of the wheel torque versus the driving speed of a motor vehicle with the hybrid drive train 1 with a battery with high discharge capacity.

The 1 shows a schematic representation of the hybrid drive train 1 intended for the hybrid drive of a motor vehicle. To drive the motor vehicle, the hybrid drive train 1 contains the drive unit 4 formed from the internal combustion engine ICE with the crankshaft 2 and the first electric machine EM1 with the rotor 3 and the second electric machine EM2 with the rotor 5. The drive unit 4 is by means of the first separating clutch C1 and the The second electric machine EM2 can be coupled to the transmission 8 by means of the second separating clutch C2. Both separating clutches C1, C2 are designed here as positive clutches 6, 7, which are actuated by an actuator, not shown, such as a switching actuator, which also engages and disengages a parking lock, also not shown. The transmission 8 contains a single electric transmission stage 9 between the second electric machine EM2 and the transmission output shaft 10 and two thermal transmission stages 11, 12 between the drive unit 4 and the transmission output shaft 10. The two transmission stages 11, 12 as well as a neutral position for decoupling the drive unit 4 from the transmission output shaft 10 are by means of the separating clutch C1 switched. Between the transmission output shaft 10 and the differential 13, the output ratio 14 of the transmission 8 is formed, in which case the gear of the gear stage 12 is designed as a fixed gear relative to the transmission output shaft 10 and at the same time forms the gear of the transmission output shaft 10 of the output toothing. The differential 13 is branched onto the drive shafts 15, 16 such as cardan shafts and hubs of the drive wheels, not shown.

The electric machines EM1, EM2 and the actuator are electrically connected to the accumulator 17 by means of a control device (not shown) and power electronics. Depending on the operating state of the motor vehicle, the charge state of the accumulator 17 and the load requirement of a driver and / or an autonomous control of the motor vehicle, the values are determined in accordance with the 2 explained operating modes of the hybrid powertrain 1 according to diagrams 300 to 500 of 4 until 6 The wheel torques shown on the drive wheels are set. It is understood that, depending on the design of the hybrid drive train and the requirements of the motor vehicle, fewer or more operating modes and/or areas can be provided for subdividing the charge state of the battery.

The 2 Table 18 shows the control of the hybrid powertrain 1 with the connection between the set operating modes MOD1 - MOD8 and the activation states of the parking lock PS, the separating clutch C1 ( 1 with the switching states C1 (1), C1 (2) of the electric machine EM1, the electric machine EM2 and the internal combustion engine ICE. Here, the symbol In contrast, the character 0 means the open position of this. The sign + means activation such as operation of the electric machine EM1, the electric machine EM2 and the internal combustion engine ICE, while the sign - means no activation of these.

The first operating mode MOD1 is the serial operation of the hybrid drive train, in which the motor vehicle is driven exclusively electrically by means of the electric machine EM2 when the parking lock is released and the internal combustion engine drives the electric machine EM1 in order to provide the electrical energy for the second electric machine EM2 and, if necessary, in the event of excess energy to charge the accumulator. In the first operating mode MOD1, the electric machine EM2 can also be operated in boost mode above its nominal power, at least for a short time. The separating clutch C1 is switched to the neutral position, that is, neither the switching state C1 (1) nor the switching state C1 (2) are activated, so that no torque is transmitted from the drive unit consisting of the internal combustion engine ICE and the electric machine EM1 to the transmission and then to the drive wheels becomes.

In the second operating mode MOD2, the hybrid drive train is operated in parallel by means of the first thermal gear stage with a lower gear ratio and thus at a lower driving speed of the motor vehicle. Here, the switching state C1 (1) of the separating clutch C1 is switched, so that torque is transmitted in parallel to the drive wheels from the internal combustion engine ICE and the second electric machine EM2. The second electric machine EM2 can be fed by the accumulator alone or by the generator-operated electric machine EM1 or by both. To provide boost operation, the electric machine EM2 can be operated above its rated power and/or the electric machine EM1 can be controlled in a motor-driving manner and support the internal combustion engine ICE, possibly with a power that is briefly above the rated power. The parking lock PS is open and the separating clutch C2 is closed.

In contrast to the operating mode MOD2, the parallel operation of the hybrid drive train in the operating mode MOD3 takes place by means of the switched switching state C1 (2) of the separating clutch C1 as a drive in the second thermal transmission stage with a larger gear ratio. The transmission of torque to the drive wheels takes place accordingly by means of the internal combustion engine ICE and, if necessary, the electric machine EM1 and the electric machine EM2. Corresponding to the operating mode MOD2, the separating clutch C2 is closed and the parking lock is opened. The translation of the second gear stage follows the first gear stage and is designed to achieve the maximum speed of the motor vehicle.

In the MOD4 operating mode, for example, when the battery charge level is low, the internal combustion engine can be used exclusively. The first electric machine EM1 can also operate as a generator be used to charge the accumulator. The second electric machine EM2 is put out of operation and the separating clutch C2 is opened. The separating clutch C1 switches the second thermal transmission stage by means of the switching state C1 (2).

The operating modes MOD5, MOD5a control the standstill of the motor vehicle with the drive unit decoupled in the neutral position by means of the separating clutch C1, closed separating clutch C2 and shut down electric machine EM2 and activated parking lock PS. In the MOD5 operating mode, the drive unit with the internal combustion engine ICE and the first electric machine EM1 is also shut down. In the MOD5a operating mode, the accumulator is charged in the stationary motor vehicle by the internal combustion engine ICE driving the generator-operated electric machine EM1.

The MOD6 operating mode provides for recuperation of kinetic energy into electrical energy, for example when the motor vehicle decelerates. When the parking lock PS is open and the separating clutch C1 is in the neutral position, the separating clutch C2 is closed. The electric machine EM2 is operated as a generator and charges the accumulator while the vehicle decelerates.

The operating modes MOD7 and MOD8 provide for purely electric driving. For this purpose, the parking lock PS is open and the separating clutch C1 is in the neutral position with the switching states C1 (1), C1 (2) deactivated. The separating clutch C2 is closed and the electric machine drives the motor vehicle forward in operating mode MOD8, for example in quiet or pollutant-limited zones, and backwards when the direction of rotation of the electric machine EM2 is reversed. The drive unit with the internal combustion engine ICE and the electric machine EM1 is shut down in the electric forward drive in operating mode MOD7. Particularly when the battery charge level is low, the battery can be charged using the internal combustion engine ICE and the generator-operated electric machine EM1 while the motor vehicle is reversing in operating mode MOD8.

The 3 shows a modeled switching sequence 100 of a switching actuator of the transmission 8 1 over time t with the switching characteristic 101 of the separating clutch C2 with the switching states open and closed. The switching characteristic curve 102 shows the switching states C1 (1), C1 (2) and the switching state open. The switching characteristic curve 103 shows the switching states open and closed of the parking lock PS. According to this representation, this switching sequence can be provided as the development of an axially actuated shift drum, with cam followers of the separating clutches C1, C2 and the parking lock PS being arranged in the relevant shifting characteristics 101, 102, 103, the corresponding sliding sleeves, shift sleeves and / or the like for adjusting the Shift switching states open, closed, C1 (2), C1 (2) when the shift drum is axially displaced.

In the diagram 100 the operating modes MOD5/MOD5a, MOD1, MOD2, MOD3, MOD4, MOD3, MOD2, MOD1, MOD5/MOD5a are shown in chronological order 2 set according to a model approach to maximum speed and back to standstill. When stationary in accordance with the operating mode MOD5 or MOD5a, the parking lock PS is closed, the two separating clutches C1, C2 are open. The approach takes place in the MOD1 operating mode in serial operation of the hybrid drive train. To do this, the parking lock PS is opened and the separating clutch C2 is closed. When switching to the operating mode MOD2 corresponding to parallel operation, the internal combustion engine is switched on by switching the separating clutch C1 into the switching state C1 (1). During the transition from the operating mode MOD2 to the operating mode MOD3, which is provided at higher driving speeds and corresponds to the parallel operation of the hybrid drive train, the separating clutch C1 is switched from the switching state C1 (1) to the switching state C1 (2). In pure operation using the internal combustion engine ICE in operating mode MOD4, the separating clutch C2 is opened. The motor vehicle is returned to a standstill in the reverse order.

The 4 shows the diagram 200 of the wheel torque M applied to the drive wheels over the driving speed v from zero to the maximum speed v (max) of a motor vehicle with the hybrid drive train 1 1 at a low charge level of the accumulator 17, for example less than or equal to 25% of the maximum charging capacity. Curves 201, 202 indicate the wheel loads acting on the drive wheels on a flat route (curve 201) and on a route with a 4% gradient (curve 202).

The operation of the motor vehicle and the hybrid drive train 1 shown takes place in accordance with the operating modes MOD1, MOD2, MOD3. The motor vehicle starts off exclusively electrically using the operating mode MOD1 with the starting torque M1, with the electrical energy being provided exclusively by the drive unit 4. At the driving speed v1, for example 20-25 km/h, the speed of the drive wheels is sufficient so that the internal combustion engine ICE can be switched on using the first thermal transmission stage 11 of the operating mode MOD2. When the driving speed v2 is reached, for example 50 km/h, it is possible to switch to the second gear stage 12 in the MOD3 operating mode. Between the driving speeds v1 and v2, depending on the driver's desired torque or ecological requirements, the motor vehicle can be operated in operating mode MOD2 or MOD3.

The 5 shows the diagram 300 of the wheel torque M applied to the drive wheels over the driving speed v from zero to the maximum speed v (max) of the motor vehicle with the hybrid drive train 1 1 at an average charge level of the accumulator 17, for example 26% to 40% of the maximum charging capacity. Curves 301, 302 indicate the wheel loads acting on the drive wheels on a flat route (curve 301) and on a route with a 4% gradient (curve 302).

In contrast to the low charge level according to diagram 200 of the 4 Due to the higher charge level of the accumulator, the adjustable operating modes mean that, in addition to the operating modes MOD1, MOD2, MOD3, the electric machines EM1, EM2 are available through the accumulator 17, which contribute to the wheel torque M. The motor vehicle is started using the operating mode MOD1 with the starting torque M1 up to the driving speed v1. In addition to or in addition to the operating mode MOD1, for example, depending on the driver's desired torque at driving speeds greater than v1, the operating mode MOD2 with the first thermal gear stage or the modified operating mode MOD2+ are available, in which the electric machine EM1 is operated by a motor and the associated electrical energy is taken from the accumulator 17 . Alternatively or additionally, the operating mode MOD1 + can be provided, in which the electric machine EM2 is fed by the accumulator in addition to the electrical energy provided by the electric machine 1. From the driving speed v2, in addition to the operating mode MOD3, the operating mode MOD3+ can be set, in which the electric machine EM1 is used as a motor in the second thermal transmission stage 12 in addition to the internal combustion engine ICE.

The 6 shows the diagram 400 of the wheel torque M applied to the drive wheels over the driving speed v from zero to the maximum speed v (max) of the motor vehicle with the hybrid drive train 1 1 at a high charge level of the accumulator 17, for example greater than 40% of the maximum charging capacity. Curves 401, 402 indicate the wheel loads acting on the drive wheels on a flat route (curve 401) and on a route with a 4% gradient (curve 402).

Due to the high state of charge of the accumulator 17, compared to the operating modes MOD1, MOD1+, MOD2, MOD2+, MOD3, MOD3+ of operation in the medium state of charge 5 additional operating modes available. In the MOD1P operating mode, the EM2 electric machine is operated at a power above the nominal power. In the operating mode MOD1C, the motor vehicle is started with the electric machine EM2, with the electrical energy being taken from the accumulator 17.

The 7 and 8th show the hybrid powertrain 1 of the 1 with accumulators 17 with different discharge capacities, each with a high state of charge. Diagrams 500, 600 show wheel torques over the driving speed v from zero to the maximum speed v(max) based on selected operating modes MOD1, MOD1P, MOD2+, MOD3+ (see 5 and 6 ) in which the discharge capacity of the accumulator is particularly stressed. The motor vehicle is started using the operating mode MOD1 with the starting torque M1. In the 7 an accumulator with a discharge capacity of 100 kW is shown 8th shows the behavior of a battery with a discharge capacity of 100 kW. With the same scaling of the wheel torque M, the MOD2+ operating mode of the accumulator with a discharge capacity of 40 kW enables a significantly higher wheel torque from a driving speed greater than v1. The operating mode MOD1P can contribute to the wheel torque at significantly lower driving speeds v, the torque contributions of the operating modes MOD1, MOD3+ are also increased in the accumulator with the larger discharge capacity, so that in order to provide a more agile driving behavior of a motor vehicle, an accumulator with a higher discharge capacity despite the higher manufacturing costs and the higher weight can be advantageous.

Reference symbol list

1

Hybrid powertrain

2

crankshaft

3

rotor

4

Drive unit

5

rotor

6

Positive coupling

7

Positive coupling

8th

transmission

9

Gear stage

10

Transmission output shaft

11

Gear stage

12

Gear stage

13

differential

14

Output translation

15

drive shaft

16

drive shaft

17

accumulator

18

Table

100

Switching sequence

101

switching characteristic

102

switching characteristic

103

switching characteristic

200

diagram

201

Curve

202

Curve

300

diagram

301

Curve

302

Curve

400

diagram

401

Curve

402

Curve

500

diagram

600

diagram

C1

Separating clutch

C1 (1)

switching state

C1 (2)

switching state

C2

Separating clutch

EM1

Electric machine

EM2

Electric machine

ICE

Internal combustion engine

M

Wheel torque

M1

starting torque

MOD1

operation mode

MOD1+

operation mode

MOD1P

operation mode

MOD1C

operation mode

MOD2

operation mode

MOD2+

operation mode

MOD3

operation mode

MOD3+

operation mode

MOD4

operation mode

MOD4+

operation mode

MOD5

operation mode

MOD5a

operation mode

MOD6

operation mode

MOD7

operation mode

MOD8

operation mode

P.S

Parking lock

t

Time

v

Driving speed

v1

Driving speed

v2

Driving speed

v(max)

Top speed

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

• DE 102018103245 A1 [0003]
• US 2016/0218584 A1 [0003]
• DE 112015006071 T5 [0003]
• EP 331372 A1 [0003]
• WO 2019/101264 A1 [0003]
• DE 102021111350 [0004]

Claims (10)

Dedicated hybrid drive train (1) of a motor vehicle with a drive unit (4) formed from a first electric machine (EM1) and an internal combustion engine (ICE) and a second electric machine (EM2), the drive unit (4) being driven by means of a first separating clutch (C1) and the second electric machine (EM2) can be connected to a gearbox (8) operatively connected to drive wheels by means of a second separating clutch (C2) and an accumulator (17) drives the electric machines (EM1, EM2) at least temporarily and can be charged by them as generators, characterized in that the transmission (8) has two thermal gear stages (11, 12) that can be switched alternatively by means of the first separating clutch (C1) and one electrical gear stage (9) that can be switched by means of the second separating clutch (C2). Dedicated hybrid powertrain (1) after Claim 1 , characterized in that the accumulator (17) has a discharge capacity greater than 40 kW. Method for controlling a dedicated hybrid powertrain (1) according to Claim 1 or 2 , characterized in that a first operating mode (MODI) with a serial drive of the motor vehicle by means of the second electric machine (EM2) and charging of the battery by means of a generator drive of the first electric machine (EM1) by means of the internal combustion engine (ICE), a second operating mode (MOD2 ) with a parallel drive of the motor vehicle by means of the drive unit (4) with selection of the first thermal transmission stage (11) and the second electric machine (EM2), a third operating mode (MOD3) with a parallel drive of the motor vehicle by means of the drive unit (4) with selection the second thermal gear stage (12) and the second electric machine (EM2) is provided, wherein a wheel torque (M) applied to the drive wheels consists of components of the operating modes (MOD1, MOD2, MOD3) depending on a driver's desired torque, a charge state of the accumulator (17) and the driving speed (v) of the motor vehicle is set. Procedure according to Claim 3 , characterized in that in a fourth operating mode (MOD4) only the drive unit (4) is used to drive the motor vehicle. Procedure according to Claim 3 or 4 , characterized in that in at least one operating mode (MOD1, MOD2, MOD3) the first electric machine is operated as a motor or as a generator. Procedure according to one of the Claims 3 until 5 , characterized in that at least one electric machine (EM1, EM2) is operated at least briefly above its rated power. Procedure according to one of the Claims 3 until 5 , characterized in that in a fifth operating mode when the motor vehicle is at a standstill, a parking lock (PS) is engaged, depending on the charging state of the accumulator (17), the accumulator (17) is charged by means of the first electric machine (EM1) which is driven by the internal combustion engine . Procedure according to one of the Claims 3 until 7 , characterized in that in a sixth operating mode (MOD6) with the drive unit (4) decoupled from the transmission and the motor vehicle moving, the accumulator (17) is charged by means of the second electric machine (EM2) driven in a generator manner by the drive wheels. Procedure according to one of the Claims 3 until 8th , characterized in that in a seventh operating mode (MOD7) the motor vehicle is driven purely electrically by means of the second electric machine (EM2) with the drive unit (4) decoupled and the internal combustion engine (ICE) stopped. Procedure according to one of the Claims 3 until 9 , characterized in that in an eighth operating mode (MOD8) the motor vehicle is driven backwards in serial operation by reversing the direction of rotation of the second electric machine (EM2).

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