DE102016221789A1 - A method of operating a hybrid powertrain, and hybrid powertrain - Google Patents

Abstract

Operating method for a hybrid drive train (1) with an internal combustion engine (2) and an electric drive machine (3) and with a switchable hybrid transmission (4), said transmission (4) having an input shaft (8) and an output shaft (9) and for changing a gear ratio between these shafts (8, 9) is arranged in discrete stages, wherein the internal combustion engine (2) by means of a slip-controllable clutch (5) is selectively conductively connectable to the input shaft (8), wherein the slip-controllable clutch (5) has an input side (5a ), which is connectable with the internal combustion engine (2) in terms of torque, and an output side (5b) which can be connected to the transmission input shaft (8) in a torque-conducting manner and wherein the electric drive machine (3) can be connected to the internal combustion engine (2) in a torque-conducting manner, wherein for switching from an output gear ratio to a destination gear The ratio of the hybrid transmission (4), the slip controllable clutch (5) is opened, the electric drive machine (3) is torque conductively connected to the internal combustion engine (2) or remains connected and respectively the speed of the input side (5a) and the output side (5b) of the slip controllable Clutch (5) are detected and, that in the event that the speed of the input side (5a) is greater than the speed of the output side (5b), a braking clutch torque from the electric drive machine (3) applied to the internal combustion engine (2) becomes.

Description

The invention relates to a method for operating a hybrid powertrain, as well as a hybrid powertrain, which is operated with such a method. As such, hybrid powertrains are known in the art, which DE 10 2015 205 932 A1 deals with a special form of such a powertrain.

The invention will be described with reference to a hybrid powertrain in an automobile with an electric drive machine and an internal combustion engine, wherein these two machines can be coupled to each other by means of a switchable transmission device for delivering drive power, this is not to be understood as a limitation of the invention to such an embodiment.

In a hybrid powertrain, an internal combustion engine is combined with an electric drive machine to overcome driving resistance when driving the vehicle. Since such vehicles cover a wide range of speeds and an internal combustion engine has only a limited operating range, a hybrid transmission with multiple gears (different, discrete gear ratios between a transmission input and a transmission output shaft) is provided. Due to the different gears an adaptation of the operating map of the internal combustion engine (speed, torque) to the load requirement (driving resistance, driving speed) is possible. When switching from an existing, engaged gear in a target gear speed matching to the internal combustion engine is necessary. For example, if you want to upshift in the acceleration phase of the 3rd in the 4th gear, this is done as follows, the internal combustion engine has a high speed in third gear, a circuit is initiated by the driver or a vehicle control unit. The torque-conducting connection between the internal combustion engine and the transmission output shaft, which is connected to the drivable axle, is disconnected. In the transmission, the 4th gear is engaged, the speed of the transmission input shaft is, as the insertion of the target gear is done very quickly, usually higher than the speed of the internal combustion engine, as it loses only slowly due to the inertia of speed. Thus, the internal combustion engine is braked quickly to the correct speed, it can be braked by a regenerative load by the electric drive machine.

The DE 10 2015 205 932 A1 proposes a switchable transmission in which during all switching operations under load, the electric machine always runs in generator mode to make a synchronization.

It is an object of the invention to provide a method of shifting a hybrid transmission with improved shifting characteristics and a powertrain controlled by this method. This object is achieved by a method according to claim 1, as well as by a hybrid powertrain, which is controlled by this method according to claim 4.

For the purposes of the invention, a hybrid drive train is understood to mean a motor vehicle drive train in which an internal combustion engine and an electric drive machine, in particular an electric motor / generator, can be used as a drive source for overcoming driving resistances.

For the purposes of the invention, an internal combustion engine is a thermal engine with internal combustion and in particular an internal combustion engine in reciprocating design, which is preferably operable according to the gasoline or diesel principle to understand.

For the purposes of the invention, an electric drive machine is understood to mean an electromechanical energy converter which can be operated in a motor and in a generator operating range. Preferably, electric power (voltage, current) can be supplied in the motor operating range of the electric drive machine and this outputs mechanical power (speed, torque). Preferably in the generator operating range of the electric drive machine mechanical power (speed, torque) can be supplied and this outputs electrical power (voltage, current) from, preferably the torque is controllable in generator operation. In particular, an electromechanical energy converter is to be understood as a so-called electric motor / generator.

For the purposes of the invention, a hybrid transmission means a shiftable transmission, in particular a speed change transmission. In particular, the hybrid transmission has 2 or more discrete transmission ratios. In this case, a transmission ratio is to be understood as meaning a transmission ratio between an input shaft and an output shaft of the hybrid transmission. Such a discrete transmission ratio can be colloquially referred to as a gear or as a switching stage. Preferably, the hybrid transmission is a spur gear with at least 2 parallel shafts, preferably as a so-called dual-clutch transmission and more preferably as a planetary gear with one or more Planetengetriebadsätzen trained. Preferably, the hybrid transmission is automatic, preferably automated and particularly preferably manually switchable. The switchable hybrid transmission is preferably set up to transmit the drive power that can be provided by the internal combustion engine, and the switchable hybrid transmission is preferably configured to transmit the drive power that can be provided by the internal combustion engine and the electric drive machine.

For the purposes of the invention, a slip-controllable clutch is understood to mean a torque transmission device which can be selectively switched between a state in which a torque can be transmitted (closed state) and a state in which no torque can be transmitted by this slip-controllable clutch (open state). Furthermore, the slip-controllable clutch has a state in which, on the one hand, a torque can be transmitted from an input side to an output side of the slip-controllable clutch and, on the other hand, the input side can be rotated in a partially closed state relative to the output side. Preferably, the slip-controllable coupling is designed as a frictional clutch, preferably a disk or disc clutch. Preferably, the slip controllable coupling is designed as a hydrodynamic torque converter. Further, the input side of the slip-controlled clutch is torque-conductively connectable to the internal combustion engine and the output side of this clutch is torque-conductively connected to the transmission input shaft and preferably the output side is connected to the transmission input shaft.

Under the torque-conducting connection of two components is to be understood in the context of the invention that from one component, a torque on the torque-conductively connected to another component is transferable. Preferably, this torque with a certain, preferably fixed, speed ratio of the one component to the other component transferable. Preferably, a torque-conducting connection can be understood as a speed-proof connection.

By detecting the rotational speed of the input side or the output side of the slip-controllable clutch is to be understood that the rotational speed of this is determined directly or indirectly. Preferably, the detection of the rotational speed is to be understood as meaning the measurement of the rotational speed of the corresponding component, or the determination of the rotational speed via other known velocity variables, such as the rotational speed of other components or the driving speed. Methods for detecting the rotational speed are known from the prior art.

If the rotational speed of the input side of the slip-controlled clutch is greater than the rotational speed of the output side, in particular in the case of an upshift operation (change from the nth to the nth + 1st shift), when the slip-controllable clutch is engaged, ie when it closes an unwanted jerk, as the torque-conducting connected to the input side of the internal combustion engine is decelerated by the closing of the clutch, as it loses only slowly due to their inertia in speed. Alternatively, or to reduce or avoid this jerk, it is possible to control the combustion process in the internal combustion engine such that at the moment of engagement of the slip-controllable clutch, the input side of this and its output side have the same or at least similar speeds. Changing the combustion process causes additional emissions, which is undesirable.

By applying a braking clutch torque from the electric drive machine to the input side of the slip-controllable clutch, the internal combustion engine can be braked such that the input side and the output side of the slip-controllable clutch have the same speed, without requiring a change of the combustion process in the internal combustion engine, thus is an improved operating method for the hybrid powertrain representable.

For the purposes of the invention, an output ratio is to be understood as meaning the discrete transmission ratio of the hybrid transmission, in which it is currently in the moment, ie the transmission ratio with which drive power can be transmitted from the input shaft to the output shaft, or is transmitted at the moment. For the purposes of the invention, a target transmission ratio is to be understood as meaning the discrete transmission ratio into which the hybrid transmission is to be switched, starting from the output transmission ratio, so that after switching drive power can be transmitted from the input shaft to the output shaft with this target transmission ratio. Figuratively speaking, in a five-speed hybrid transmission, which is to be switched during an acceleration phase from 3rd to 4th gear, the 3rd gear represents the output gear ratio and the 4th gear is the target gear ratio.

In a preferred embodiment of the invention, the internal combustion engine when switching from the output ratio in the Target translation operated in a low-consumption or consumption-optimal operating range. Preferably, the fuel supply to the internal combustion engine is interrupted when switching from the output gear ratio to the target gear ratio. In particular, by such control of the internal combustion engine, both the emissions and the fuel consumption of the internal combustion engine can be lowered and an improved operating method for the hybrid powertrain is thus represented.

In a preferred embodiment of the invention, the electric drive machine for applying the braking clutch torque is operated in a regenerative operating range. In particular, by means of a regenerative operating range, the conversion of mechanical power (speed, torque) into an electrical power (voltage, current) is possible. Preferably, this electrical power, which is obtained by the application of the braking clutch torque, fed into a hybrid vehicle electrical system, or supplied thereto. In particular, such a control of the electric drive machine energy recovery is possible and thus the efficiency of the hybrid powertrain can be increased.

Next, a hybrid powertrain is provided according to claim 4, which has the internal combustion engine, the electric drive machine and the switchable hybrid transmission with the input and output shaft, which is switchable in at least two different, discrete gear ratios, ie in particular at least a first and another gear , Further, the hybrid powertrain is controllable by means of a control device on which the above-mentioned operating method is executable on a data memory, preferably on an internal data memory and preferably on a memory module, as a computer program product.

Preferably, the slip-controllable clutch is designed as a frictional clutch, preferably as a hydrodynamic torque converter. Further preferably, the frictional clutch is designed as a disk or preferably disk clutch. Preferably, the slip-controllable clutch is designed as a single or multiple disc clutch and preferably as a multi-plate clutch with a plurality of friction plates. In particular, such a drive train has an efficient switching behavior.

In a preferred embodiment, the electric drive machine can be directly connected with the internal combustion engine in a torque-conducting manner. Preferably, the electric drive machine with the internal combustion engine rotatably connected. Preferably, the electric drive machine is koxial and preferably concentric to an output shaft of the internal combustion engine, in particular a crankshaft of the internal combustion engine arranged. Further preferably, the prime mover is designed as a so-called crankshaft starter generator. In particular, by means of such an embodiment of the invention, a particularly space-saving design is possible.

In a preferred embodiment of the invention, the electric drive machine by means of an intermediate gear with the internal combustion engine can be connected in a torque-conducting manner. Preferably, this intermediate gear is designed as a traction mechanism, preferably as a positive traction mechanism and particularly preferably as a chain transmission or more preferably as a toothed or ribbed belt transmission. Further preferably, the intermediate gear is designed as a gear transmission. In particular, by means of such an embodiment of the invention, it is possible to position the electric drive machine almost independently of the internal combustion engine.

In a preferred embodiment of the invention, the electric drive machine, based on the geometry, between the internal combustion engine and the hybrid transmission is arranged. In particular, by means of such a configuration, a particularly space-saving design of the hybrid powertrain is possible.

In a preferred embodiment of the invention, the electric drive machine, based on the geometry, arranged in a housing of the hybrid transmission. In particular, by means of such an embodiment of the hybrid powertrain a modularization of the hybrid transmission and the internal combustion engine is made possible.

The proposed powertrain can be used in a motor vehicle, preferably a car to overcome the driving resistance.

• 1: einen schematisierten Hybridantriebsstrang,
• 2: einen vereinfachten Ablaufplan für das Betriebsverfahren.

In the figures explained below, individual features and embodiments of the invention are shown in more detail, in which:

• 1 a schematized hybrid powertrain,
• 2 : a simplified operational procedure flow chart.

In 1 is a schematic representation of a hybrid powertrain 1 shown. The hybrid powertrain 1 has an internal combustion engine 2 and an electric motor generator 3 up and is by means of the control unit 2a controllable. From these two drive machines ( 2 . 3 ) Drive power is available to overcome driving resistances. Those of these prime movers ( 2 . 3 ) provided drive power is by means of the hybrid transmission 4 towards the drive wheels 6 transfer. The drive wheels 6 may be front wheels and additionally or alternatively rear wheels (front, four-wheel, rear wheel drive).

The internal combustion engine 2 is about the clutch 5 selectively with the hybrid transmission 4 connectable. The transmission ratio of the hybrid transmission 4 , So the ratio between the input shaft 8th and the output shaft 9 this transmission 4 , is changeable in discrete stages. In this case, such a discrete translation stage colloquially as a transition.

Next, the hybrid powertrain 1 a dual mass flywheel 7 for reducing torsional vibrations of the internal combustion engine 2 on. With the position 7a is an alternative position for the arrangement of the dual mass flywheel 7 the internal combustion engine 2 shown.

The hybrid powertrain 1 is via the hybrid powertrain control unit 2a controlled. On the hybrid powertrain control unit 2a the control method is stored on an internal memory module as an executable computer program.

The internal combustion engine 2 as well as the electric motor generator 3 are non-rotatable with the input side 5a the clutch 5 connected. The input shaft 8th of the hybrid transmission 4 is rotatable with the output side 5b the clutch 5 connected.

The electric drive machine 3 is driven at the upshift from the output gear ratio in the target gear ratio such that this is a regenerative braking torque to the internal combustion engine 2 applies (generator clutch torque). The recovered via the regenerative braking torque electrical power is the energy storage / electrical system 3a fed.

In 2 a schematic process flow for the operating method for the proposed hybrid powertrain is shown. In order to achieve a better overview, reference signs are omitted for individual elements 1 indicated, although the element as such in 2 not shown.

In the first step 10, a shift request, ie a change from the output gear ratio to the target gear ratio is requested and the slip controllable clutch ( 5 , not shown) opens.

As far as the speed of the input side ( 5a , not shown) is greater than the speed of the output side ( 5b , not shown) is in the next step 20 via the electric motor generator ( 3 , not shown) a regenerative braking torque applied to the internal combustion engine. At the same time, in the next step 30, the hybrid transmission is switched from the output gear ratio to the target gear ratio. In step 40, the slip-controllable clutch is closed again and the internal combustion engine can again deliver drive power via the hybrid transmission to the drivable wheels.

In other words, hybrid vehicles today have, in addition to the internal combustion engine, one or more electric motors that can be coupled to the internal combustion engine in order to provide electrical energy for the vehicle electrical system as a generator during operation of the electric motor.

Preferably, this arrangement should be used to quickly synchronize the rotational energy of the engine during transmission circuits by building a regenerative load (regenerative clutch torque) on the electric motor generator to the target speed. This is done with the aim of the combustion process in the internal combustion engine by the switching intervention as little as possible to influence.

For this purpose, the following configuration is proposed:

Use of the electric motor generator in the internal combustion engine drive (use of existing electric motor generators in hybrid vehicles, or installation of an electric motor generator in a "conventional" vehicle).

• - kurbelwellenfeste Anbindung (z.B. Kurbelwellenstartergenerator (KSG) oder Starter-Generator angetrieben über Kette/Zahnradstufe/Riemen,
• - Anordnung zwischen Verbrennungsmotor und Hybridgetriebe mit der Maßgabe einer drehzahlfesten Kopplung zur Kurbelwelle der Verbrennungskraftmaschine während des Schalteingriffes (Wechsel aus dem Ausgangsübersetzungsverhältnis in das Zielübersetzungsverhältnis),
• - Anordnung innerhalb des Hybridgetriebes mit der Maßgabe einer drehzahlfesten Koppelung zur Kurbelwelle der Verbrennungskraftmaschine während des Schalteingriffes,
• - insbesondere aus Komfortgründen ist weiterhin vorgesehen, dass zum Abtrieb ein schlupfendes Getriebeelement (schlupfsteuerbare Kupplung) existiert, mit welchem der für den Fahrer störenden Abbau kinetischer Energie aus dem Fahrzeug verringer- oder verhinderbar ist.

This electric motor generator can be arranged at different positions, as follows, not exhaustive, enumeration shows:

• - crankshaft fixed connection (eg crankshaft starter generator (KSG) or starter-generator driven via chain / gear stage / belt,
• - Arrangement between internal combustion engine and hybrid transmission with the proviso of a rotationally fixed coupling to the crankshaft of the internal combustion engine during the shifting engagement (change from the output gear ratio to the target gear ratio),
• Arrangement within the hybrid transmission with the proviso of a rotationally fixed coupling to the crankshaft of the internal combustion engine during the switching engagement,
• - Especially for reasons of comfort is further provided that the output of a slipping transmission element (slip controllable clutch) exists, with which the disturbing for the driver degradation of kinetic energy from the vehicle can be reduced or prevented.

LIST OF REFERENCE NUMBERS

1

Hybrid powertrain

2

Internal combustion engine

2a

Hybrid powertrain control module

3

Electric motor generator

3a

Board power / energy storage

4

hybrid transmission

5

slip controllable coupling

5a

Input side of the starting clutch

5b

Output side of the starting clutch

6

drive wheels

7

Dual Mass Flywheel

7a

Alternative position for dual-mass flywheel

8th

input shaft

9

output shaft

10 - 40

steps

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015205932 A1 [0001, 0004]

Claims (9)

Operating method for a hybrid drive train (1) with an internal combustion engine (2) and an electric drive machine (3) and with a switchable hybrid transmission (4), said transmission (4) having an input shaft (8) and an output shaft (9) and for changing a gear ratio between these waves (8, 9) is arranged in discrete stages, wherein the internal combustion engine (2) is selectively connectable to the input shaft (8) by means of a slip-controllable clutch (5), the slip-controllable clutch (5) having an input side (5a) which is connectable with the internal combustion engine (2) in terms of torque and an output side (5b), which is torque-conductively connectable to the transmission input shaft (8), and wherein the electric drive machine (3) is torque-conductively connectable to the internal combustion engine (2), wherein the slip-controllable clutch for shifting from an output gear ratio to a target transmission ratio of the hybrid transmission (4) (5) is opened, the electric drive machine (3) is torque-conductively connected to the internal combustion engine (2) or remains connected and in each case the rotational speed of the input side (5a) and the output side (5b) of the slip-controlled clutch (5) are detected and that in the event that Speed of the input side (5a) is greater than the rotational speed of the output side (5b), a braking clutch torque from the electric drive machine (3) is applied to the internal combustion engine (2). Operating method according to one of the preceding claims, characterized in that the internal combustion engine (2) is operated when switching from the Ausgangsübersetzungsverhältnis in the Zielübersetzungsverhältnis in a low-consumption or consumption-optimal operating range. Operating method according to one of the preceding claims, characterized in that the electric drive machine (3) is operated for applying the braking clutch torque in a regenerative operating range, that electrical power which is generated by the application of the braking clutch torque to the electric drive machine (3) Hybrid vehicle electrical system (3a) can be fed. A hybrid powertrain having an internal combustion engine and an electric prime mover and having a hybrid switchable transmission (4), said transmission having an input shaft (8) and an output shaft (9) and arranged to change a gear ratio between said shafts (8, 9) in discrete stages , in which the internal combustion engine (2) is selectively connectable to the input shaft (8) by means of a slip-controllable clutch (5), the slip-controllable clutch (5) having an input side (5a) which is connectable with the internal combustion engine (2) in terms of torque and an output side (5b), which is torque-conductively connected to the input shaft (8) and wherein the electric drive machine (3) is torque-conductively connected to the internal combustion engine (2), wherein the hybrid powertrain (1) with a hybrid vehicle control unit (2a) is controllable on which a Method according to one of the preceding claims is stored as an executable computer program product and that the slip-controllable coupling (5) is designed as a hydraulic torque converter or as a Lammellenkupplung with at least one friction plate. Hybrid powertrain after Claim 4 , characterized in that the electric drive machine (3) directly to the internal combustion engine (2) is rotatably connected. Hybrid powertrain after Claim 4 , characterized in that the electric drive machine (3) by means of an intermediate gear with the internal combustion engine (2) is torque-conductively connectable. Hybrid powertrain after one of Claims 4 to 6 , characterized in that the electric drive machine (3) is arranged geometrically between the internal combustion engine (2) and the hybrid transmission (4). Hybrid powertrain after one of Claims 4 to 6 , characterized in that the electric drive machine (3) is arranged geometrically in the hybrid transmission (4). Motor vehicle with a hybrid powertrain according to one of Claims 4 to 8th ,

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