EP2969621A1

EP2969621A1 - Drive train for a hybrid vehicle

Info

Publication number: EP2969621A1
Application number: EP14709936.0A
Authority: EP
Inventors: Dieter Grillenberger; Stefan LICHTENEGGER; Achim REINBACHER
Original assignee: AVL List GmbH
Current assignee: AVL List GmbH
Priority date: 2013-03-15
Filing date: 2014-03-12
Publication date: 2016-01-20
Also published as: JP2016511190A; CN105307889A; WO2014140096A1; AT513986A4; AT513986B1

Abstract

The invention relates to a drive train (1) for a hybrid vehicle, comprising an internal combustion engine (ICE), at least one electric machine (EM1, EM2), and a power-split transmission (4) having three connections (4a, 4b, 4c), wherein a first connection (4a) has a drive connection to at least one electric machine (EM2), a second connection (4b) has a drive connection to the internal combustion engine (ICE), and a third connection (4c) preferably formed by a summation shaft (s) has a drive connection to an output shaft (2) of the vehicle. Furthermore, a torque guiding module (5) formed by a two-course four-shaft transmission is connected to the first connection (4a).

Description

Powertrain for a hybrid vehicle

The invention relates to a drive train for a hybrid vehicle having an internal combustion engine and at least one electric machine, having a power-split transmission having three connections, a first connection having at least one electric machine, a second connection to the internal combustion engine and one preferably formed by a sum shaft third terminal is drivingly connected to an output shaft of the vehicle.

Due to the lower gravimetric energy density of batteries compared to fossil fuels and the relatively long charging time of the batteries, electric vehicles generally have shorter ranges than vehicles with internal combustion engines. In order to ensure an acceptable range for a comparable gross vehicle weight, vehicles with electric drive often use a so-called range extender. If necessary, an internal combustion engine directly drives a generator, which feeds additional energy into the battery. In these construction concepts, no mechanical power path is provided between the internal combustion engine and the drive wheels. This has the advantage that an optimal design of the internal combustion engine to a few operating points and an optimal design of the battery size can be done with low complexity and little effort. Since there is no mechanical power transmission between internal combustion engine and drive wheels, however, there are high losses in the engine power path due to frequent energy conversion between internal combustion engine -> generator -> high voltage system -> battery -> high voltage system -> engine -> transmission. The electric machine is the drive and must be designed for greater power.

In power-split hybrid drives, part of the power provided by the internal combustion engine is directly transmitted mechanically to the drive wheels via a two-speed transmission for power branching. In order to meet the static requirements (torque equilibrium support torque) of the system, depending on the operating condition, power must still be supplied or removed to the gearbox. This is done by motor or generator operation of an electric machine. The power split thus takes place via a purely electrical power path.

In order to operate the internal combustion engine stationary at an operating point, the power supply from the power split of the required drive power, by the motor or generator operation of a be adapted to another electric machine. Depending on the operating condition and power requirement, a reactive power flow in the electric power path can therefore occur as a result of the principle.

Possible reactive power flow:

• electrical machine 1 -> high voltage system -> battery -> high voltage system -> electric motor 2.

• Electric motor 2 -> high voltage system -> battery -> high voltage system -> electric machine 1.

This allows the advantages of a mechanical power path for the internal combustion engine and the optimal design of the internal combustion engine to a few operating points, and a lower vehicle mass can be combined by smaller batteries. The disadvantage, however, is that the power split is purely electrical, resulting in high losses due to frequent energy conversion. The possible reactive power flow in the electric power path causes low efficiency. In addition, there is a large control effort through the system.

DE 199 09 424 AI discloses a hybrid transmission for vehicles, consisting of a drive shaft, an output shaft, a continuously variable actuating gear and a mechanical superimposition change gear. The superposition gear is a five-shaft planetary gear with a ridge shaft as the transmission output shaft. The bridge carries several sets of intermeshing planets. The planets mesh with two ring gears and two sun gears. The two sun gears are connected to each other via a stepless electric control gear. A first ring gear is fixedly connected to the internal combustion engine. The second ring gear is connected via a brake with the transmission housing.

EP 1 279 545 A2 describes a hybrid drive train for a vehicle with a four-element and two-degree-of-freedom planetary gear with two sun gears, a planet carrier and at least one ring gear. The ring gear and the planet carrier are connected to the drive shaft of an internal combustion engine. The sun gears are each connected to electrical machines.

The object of the invention is to improve the efficiency and to reduce the control effort. According to the invention, this is achieved in that a torque-guiding module formed by a two-shaft four-shaft transmission is connected to the first connection.

Under a power split two-speed (degree of operation = 2) transmission is generally understood a gearbox with two kinematic degrees of freedom: By specifying the speeds of two shafts, the system is kinematically uniquely determined. If, in addition, a torque of a connection shaft is specified, then the system is also completely statically defined. Generally, a transmission / partial transmission for power transmission must at least always have a connecting shaft more than it has kinematic degrees of freedom. Thus, the simplest two-speed transmission has exactly three connection shafts. Epicyclic gears / planetary gears form the simplest version of two-way three-shaft transmissions. From the condition that the sum of all moments = 0, it follows that the connection torques of a two-speed transmission must be partly positive and partly negative. There are always two moments with the same sign and one with the opposite sign, where the single moment corresponds to the sum of the other two moments. The wave that carries the single moment is called the sum wave, the other two waves are called difference waves.

If the stand ratio of a planetary gear is negative, so it is a so-called minus gear, so are the two central shafts at the same time the difference waves and the land wave is the sum wave. If the stationary gear ratio of a planetary gearbox is positive, it is generally called a plus gearbox. A central shaft and the bridge shaft are differential waves, the remaining central shaft is the sum wave.

It is preferably provided that the torque-guiding module has four connections, wherein a first module connection with a first electric machine, a second module connection with a second electrical machine and further module connections are drive-connected to the first and second connection of the power-branching transmission. A particularly high efficiency and low control effort can be achieved if the torque-guiding module has two two-shaft three-shaft transmission, wherein the differential shafts of the two three-shaft gear are coupled together and wherein the sum of the first two-shaft three-shaft transmission, the first module connection and the sum of the second two-shaft three-shaft transmission the second Module connection forms.

Two dual-shaft three-shaft transmission together by a double coupling a four-shaft four-shaft transmission with four ports, one of which the sum of the first partial transmission, another the sum of the second partial transmission, and the two remaining module connections form the coupled differential shaft strands of the partial transmission.

It can be provided that two differential shafts of the first and second three-shaft transmission of the torque-guiding module are coupled directly to a positive differential shaft train and two further differential shafts of the first and second two-way three-shaft transmission via a reverse gear to a negative differential wave train. Thus, the positive differential wave train forms a positive ratio and the negative differential wave train forms a negative ratio between the two partial transmissions.

The first partial transmission acts as an open differential, which distributes the drive torque of the first module connection in a certain ratio to the module connections coupled to the differential shaft sections. A torque applied to the second connection ensures a redistribution of the drive torques of the connections coupled to the differential shaft sections.

In principle, the torque distribution can take place either on the drive side or on the output side by the torque-guiding module.

In a first embodiment variant of the invention, it is provided that a differential shaft of a differential shaft train of the torque-guiding module is drive-connected to the first connection and a further differential shaft of the other differential-wave train is drive-connected to the second connection of the power-split transmission. The first connection of the power split transmission is connected either to the module connection of the positive differential wave train or the negative differential wave train. Conversely, the second connection of the power-split transmission is connected to either the negative differential shaft train or the positive differential shaft train of the torque-guiding module.

In a second embodiment of the invention, it is provided that a differential shaft of a differential shaft of the torque-torque steering module with the second terminal and a differential shaft of the other differential shaft is drivingly connected to the third terminal of the power-split transmission.

The third connection of the power-split transmission is connected to either the direct or the reverse differential shaft of the torque-guiding module. Conversely, the second connection of the power split transmission is either with the reverse or with the direct difference shaft train of the torque of the guide module connected.

The powertrain thus has two main assemblies with different functions:

1) Power split two-way transmission for CVT (Continuous Variable Transmission) functionality

2) Torque guide module (TVM = Tork Vectoring Module) for dynamic power distribution in the system.

The present invention provides not only all the advantages of hybrid drives with power-split transmissions, such as a mechanical power path for the internal combustion engine, optimal design of the engine to a few operating points and low vehicle mass by small-sized battery, but also low losses and thus relatively high efficiency by the mechanical power split, since the frequency of energy conversion can be reduced. In addition, a much lower regulatory burden is required.

The inventions will be explained in more detail below with reference to FIGS. Show it :

1 shows a drive train according to the invention in a first embodiment;

Fig. 2 shows a first variant of the embodiment of Fig. 1;

Fig. 3 shows a second variant of the embodiment of Fig. 1;

4 shows a drive train according to the invention in a second embodiment;

Fig. 5 shows a first variant of the embodiment of Fig. 4;

Fig. 6 shows a second variant of the embodiment of Fig. 4;

7 shows a drive train according to the invention in a third embodiment;

Fig. 8 shows a first variant of the embodiment of Fig. 7;

FIG. 9 shows a first variant of the embodiment from FIG. 7; FIG. 10 shows a drive train according to the invention in a fourth embodiment;

11 shows a first variant of the embodiment from FIG. 10; and

12 shows a second variant of the embodiment from FIG. 10.

Functionally identical parts are provided in the embodiments and variants with the same reference numerals.

The figures each show the drive train 1 with the drive sources formed by the internal combustion engine ICE, the first electric machine EM I and the second electric machine EM2, wherein at least one drive wheel 3 of a vehicle is driven via the output shaft 2. In the drive train 1, a power-splitting transmission 4 with three terminals 4a, 4b, 4c is arranged. The first terminal 4a is connected to the first and second electric machines EM I, EM2 via a torque guide module 5 having four module terminals 5a, 5b, 5c, 5d. The second terminal 4b is connected to the drive shaft 6 of the internal combustion engine ICE.

The power-split transmission 4 is designed as a two-speed transmission with two kinematic degrees of freedom. Such three-shaft transmission, which are formed by planetary gear or L, always have two waves, which have the same sign relative to the shaft torque, and a shaft with opposite signs. The waves with the same sign are called difference waves, the wave with opposite sign is called the sum wave. As a ridge wave wave is called, which can only transmit clutch power. Shafts, which can transmit both coupling performance and rolling power, are referred to as central shafts. A three-shaft gearbox has a unique torque and speed behavior in relation to the difference and sum waves. To describe a three-shaft gear kinematically, one manages the so-called state translation. Stand translation is defined as the ratio between the two central shafts when the bridge shaft is stationary. Stand translation can be positive or negative, which in turn makes it necessary to distinguish between so-called plus and minus transmissions. A minus gear designates a three-shaft gearbox, in which both central shafts at the same time represent the differential shafts, the rest of the web shaft is here the sum shaft.

A plus gear refers to a three-shaft gearbox, in which the web shaft and one of the two central shafts represent the difference waves, the remaining central shaft is then the sum shaft. In a simple planetary gear with only one planetary gear, which meshes on the one hand with the sun gear and on the other hand also meshes with the ring gear, the two central shafts sun gear and ring gear are the difference waves, the land wave is the sum wave. This planetary gear set has the kinematics of a minus gearbox.

In a planetary gear set with one or more pairs of planetary gears, wherein in each case the first planetary gear meshes with the sun gear and the second planetary gear, and the second planetary gear with the ring gear and the first planetary gear, they form web shaft and the sun gear as the first central shaft, the difference waves, the ring gear as second central shaft is the sum wave. This planetary gear set thus has the kinematics of a plus gear. In the present power-split two-speed transmission 4, for example, a negative gear can be used. By specifying the speeds on two shafts, the system is kinematically determined. If, in addition, a torque is specified by a connection, then the system is also completely statically defined.

In the present case, the first and the second connection 4a, 4b of the power-split transmission 4 are formed by differential waves d and the third connection 4c by a sum wave s.

The torque-guiding module 5 is constituted by two two-shaft three-shaft transmissions (partial transmissions) Ti and T ₂ , which together by a double coupling form a two-shaft four-shaft transmission with the module connections 5a, 5b, 5c and 5d. The first module connection 5a connected to the first electric machine EM I is formed by the sum wave Si of the first three-shaft transmission Ti. The second module connection 5b connected to the electric machine EM2 is formed by the sum shaft S _{2 of} the second three-shaft transmission T ₂ . The differential shafts di ^{+ of} the first three-shaft transmission Ti and d ₂ ^{+ of} the second three-shaft transmission T ₂ are coupled together to form a positive differential wave train D ⁺ . The differential waves df and d ₂ ^"of the first and second three-shaft transmissions TI and T2 are coupled via a reverse gear U to a negative differential shaft train D ^" .

The partial transmission Ti acts as an open differential, which distributes the drive torque of the first module connection 5a in a certain ratio to the module connections 5c and 5d. A torque applied to the second module connection 5b ensures a redistribution of the output torques of the connections 5c and 5d.

Basically, the figures can be divided into two groups. FIGS. 1 to 6 deal with a first group of embodiments and variants with other embodiments. drive-side torque distribution by the torque-guiding module 5. FIG. 7 to FIG. 12 show a second group of embodiments and variants with output-side torque distribution by the torque-guiding module 5, wherein FIG. 1 shows a first main embodiment, FIG. 4 shows a second main embodiment, FIG. 7 shows a third main embodiment and 10 shows a fourth main embodiment. For each main version there are sub-variants, which are shown in Figs. 2 and FIG. 3, Fig. 5 and FIG. 6, Fig. 8 and FIG. 9 or FIG. 11 and FIG. 12 are shown.

The representation of the in Figs. 1, Fig. 4, Fig. 7, and FIG. The main embodiments shown in FIG. 10 are in the so-called wolf symbolism, wherein each planetary gear is represented by a circle for the housing and by three dashes for the three terminals. The ridge waves are indicated by a line projecting into the circle, the sum waves characterized by a double line.

Reference numeral 7 indicates a drive ratio or a vehicle differential.

In all variants, the first three-shaft gear drive Ti is designed as a plus transmission and the second three-shaft transmission T ₂ as a minus transmission in the case of the torque-guiding module 5. The Fig. 2 and FIG. 3, Fig. 5 and FIG. 6, Fig. 8 and FIG. 9, and Fig. 11 and FIG. 12 differ in each case in that the central shafts are reversed in the power-split transmission 4. In the variants of FIG. 2, Fig. 5, Fig. 8 and FIG. 11, the sun gear L _{s of} the planetary gear L of the power-split transmission 4 is connected to the drive shaft 6 of the internal combustion engine ICE. The ring gear L _H, however, is connected to the web Tis _{t of} the first three-shaft gear Ti of the torque-guiding module 5.

In the variants of FIG. 3, Fig. 6, Fig. 9 and FIG. 12, however, the drive shaft 6 of the internal combustion engine ICE is connected to the ring gear L _{H of} the planetary gear L of the power- _split transmission 4, the sun gear L _s, however, with the web T _{1St of} the first three-shaft _gear Ti.

In the in Figs. 2 and FIG. 3 variants, the sun gears T _1S and T _{2S of} the first and second three-shaft transmission TI, T2 are connected to the drive shaft 6 of the internal combustion engine ICE. On the ring gear Ti _H, the first electric machine EM I acts. The second electric machine EM2 acts on the web T _{2st of} the second three-shaft _transmission T ₂ . The ring gear T _{2H of} the second three-shaft gear T ₂ and the web Ti _{St of} the first three-shaft gear Ti is coupled to each other via the reverse gear U. The web T _{st of} the power-split transmission 4 is connected to the output shaft 2. Unlike the Fig. 2 and FIG. 3 is in the embodiments of FIG. 5 and FIG. 6 that central shaft of the branched transmission 4, which is not connected to the drive shaft 6 of the internal combustion engine ICE, connected both to the sun gear T _{1S of} the first three-shaft gear Ti, as well as with the sun gear T ₂ s of the second three-shaft transmission T ₂ .

The examples of FIG. 8 and FIG. 9 with a - with respect to the power-split transmission 4 - the output side connected to the drive train 1 coupled positive differential wave train D ⁺ show arrangements analogous to FIGS. 2 and FIG. 3, in which that central shaft of the power-split transmission 4, which is not connected to the drive shaft 6 of the internal combustion engine ICE, is connected to the first three-shaft transmission Ti. In Fig. 8, the ring gear L _{s of} the power- _split transmission 4 is connected to the web T _{1St of} the first three-shaft transmission Ti. By contrast, in FIG. 9, the sun gear l_s of the planetary gear set L of the power-split transmission 4 is connected to the web Tis _{t of} the first three-shaft drive Ti. The ring gear Ti _{H of} the first three-shaft gear Ti is connected to the first electric machine EM I. The sun gears T _1S and T _{2S of} the first and second three-shaft transmission Ti, T ₂ are fixedly connected to the output shaft 2. The web T _1St is connected to the ring gear T _2H via the reversing stage U. The second electric machine EM2 engages the web T _{2st of} the second three-shaft _transmission T ₂ .

The in Figs. 11 and FIG. 12 illustrated examples show variants of a torque-guiding module 5 coupled on the output side with respect to the power-split transmission 4 to the drive train 1, wherein in FIG. 11, the sun gear 4 _{S of} the planetary gear set L of the power-split transmission 4 is coupled to the drive shaft 6 of the internal combustion engine ICE and the ring gear L _{H of} the planetary gear set L with the sun gears T _1S and T _{2S of} the first and second three-shaft transmission Ti, T _{2 is} drivingly connected. The web L _{ST of} the power- _split transmission 4 is connected to the web T _1St . This web T _{1St of} the first three-shaft _transmission Ti is coupled via the reverse gear U with the ring gear T _{2H of} the second three-shaft gear T ₂ . At the ring gear Ti _{H of} the first three-shaft gear Ti, the first electric machine EM I attacks. The second electric machine EM2 is connected to the web T _{2st of} the second three-shaft _transmission T ₂ . From the in Fig. 11 arrangement differs Fig. 12 only in that the central shafts of the power-split transmission 4 are reversed. In detail, the drive shaft 6 of the internal combustion engine ICE is connected to the hollow shaft 1_H of the planetary gearset L of the power-split transmission 4, and the sun gear L _{s of} the planetary gearset L is connected to the sun gears T _{1S of} the first three-shaft gear Ti and the sun gear T _{2S of} the second three-shaft gearbox T ₂ . The connections 4a, 4b, 4c of the power-split transmission 4 and the module connections 5a, 5b, 5c, 5d of the torque-guiding module 5 can be physically formed connections, such as connection shafts, between the transmission parts, or virtual connection points between transmission elements or act without component separation. The position of the connections is shown in FIGS. 2, Fig. 3, Fig. 5, Fig. 6, Fig. 8, Fig. 9, Fig. 11 and FIG. 12 thus shown only schematically.

Claims

P A T E N T A N S P R E C H E

Drive train (1) for a hybrid vehicle with an internal combustion engine (ICE) and at least one electric machine (EM I, EM2), with a power split transmission (4) having three connections (4a, 4b, 4c), wherein a first connection (4a) with at least one electric machine (EM2), a second connection (4b) to the internal combustion engine (ICE) and a third connection (4c), preferably formed by a sum shaft (s), being connected to an output shaft (2) of the vehicle, characterized in that a torque-guiding module (5) formed by a two-shaft four-shaft transmission is connected to the first connection (4a).

Drive train (1) according to claim 1, characterized in that the torque-guiding module (5) has four module connections (5a, 5b, 5c, 5d), wherein a first module connection (5a) with the first electric machine (EM I), a second module connection (5b) to the second electric machine (EM2) and further module connections (5c, 5d) are drive-connected to the first and second connection (4a, 4b) of the power-split transmission (4).

Drive train (1) according to Claim 2, characterized in that the torque-guiding module (5) has two two-shaft three-shaft transmissions (Ti, T ₂ ) each having two differential shafts (df, di ⁺ ; d ₂ ^" , d ₂ ⁺ ) and a sum shaft ( Si; S ₂ ), wherein the difference waves (df, di ⁺ ; d ₂ ^" , d ₂ ⁺ ) of the two three-shaft transmissions (Ti, T ₂ ) are coupled together and wherein the sum wave (Si) of the first two-way three-shaft transmission (Ti) the first module connection (5a) and the sum shaft (S ₂ ) of the second two-phase three-shaft transmission (T ₂ ) form the second module connection (5b).

Drive train (1) according to claim 3, characterized in that the first three-shaft gear (Ti) is designed as a plus gear and the second three-shaft gear (T ₂ ) as a negative gear.

Drive train (1) according to claim 3 or 4, characterized in that two differential waves (di ⁺ , d ₂ ⁺ ) of the first and second three-shaft transmission (Ti, T ₂ ) of the torque-guiding module (5) directly to a positive differential wave train (D ⁺ ) and two further differential waves (df, d ₂ ^" ) of the first and second two-phase three-shaft transmission (Ti, T ₂ ) via a reverse gear (U) to a negative differential wave train (D ^" ) are coupled together.

6. powertrain (1) according to claim 5, characterized in that a differential shaft train (D ⁺ ; D ^" ) of the torque-guiding module (5) with the first terminal (4a) and the other differential wave train (D ^" ; D ⁺ ) with the second connection (4b) of the power-split transmission (4) is drive-connected.

7. powertrain (1) according to claim 6, characterized in that the first terminal (4a) of the power-split transmission (4) with the positive differential shaft train (D ⁺ ) and the second terminal (4b) of the power-split transmission (4) with the negative Differential shaft train (D ^" ) of the torque-guiding module (5) is connected.

8. Drive train (1) according to claim 6, characterized in that the first connection (4a) of the power-split transmission (4) with the negative differential shaft train (D ^" ) and the second connection (4b) of the power-split transmission (4) with the positive Differential shaft train (D ⁺ ) of the torque-guiding module (5) is connected.

9. Drive train (1) according to one of claims 1 to 8, characterized in that a differential shaft train (D ⁺ ; D ^" ) of the torque-guiding module (5) with the first terminal (4a) and the other differential wave train (D ^" ; ⁺ ) of the torque-guiding module (5) is drive-connected to the third connection (4c) of the power-split transmission (4).

10. Drive train (1) according to claim 9, characterized in that the first terminal (4a) of the power-split transmission (4) with the negative differential shaft train (D ^" ) of the torque-guiding module (5) and the third terminal (4c) of the power-split Gear (4) with the positive differential shaft train (D ⁺ ) of the torque-guiding module (5) is connected.

11. Drive train (1) according to claim 9, characterized in that the first terminal (4a) of the power-split transmission (4) with the positive differential shaft train (D ⁺ ) of the torque-guiding module (5) and the third terminal (4c) of the power-split Gear (4) with the negative differential shaft train (D ^" ) of the torque-guiding module (5) is connected.

2014 03 12

Fu / Bt