DE102007053671A1 - Drive train for a motor vehicle - Google Patents

Abstract

The invention relates to a drive train for a motor vehicle with an internal combustion engine (1), a switchable clutch (3) and an electric machine (4). An alternative drive train, which is characterized by high efficiency and / or high comfort, further comprises a hydrodynamic converter (2) and an automatic transmission (5), wherein the switchable clutch (3) separates the drive train such that the hydrodynamic converter (2) and the internal combustion engine (1) on one side and the electric machine (4) and the automatic transmission (5) are located on the other side.

Description

The The invention relates to a drive train according to the preamble of the claim 1.

From the DE 10 2004 045 269 A1 is a drive rod for a motor vehicle with hybrid drive, in which between each an electric machine and an internal combustion engine or a transmission unit, a clutch is arranged. Here, for example, when starting, with closed clutches, the torque generated by the engine and the electric machine transmitted through the gear unit to the drive wheels. If the electric machine can no longer produce a desired torque due to an excessively low state of charge of its energy source, then, in order to nevertheless obtain the desired torque at the drive wheels, the transmission unit ratio is changed accordingly. As a maximum torque is thus the sum of the moments of the internal combustion engine and the electric machine, taking into account the translation of the gear unit available.

Around When starting to realize a higher moment, it is known in conventional drives, hydrodynamic transducers in Use connection with an automatic transmission.

A Combination of these teachings, with the coupling between electrical Machine and gear unit by a hydrodynamic converter is replaced is also known. Thus, the moment of the electric Machine, and also the internal combustion engine, through the front of the automatic transmission arranged hydrodynamic converter increases when starting become.

task the invention is to propose an alternative drive train, which is characterized by high efficiency and / or high comfort.

The The object is solved by the features of claim 1. Accordingly, the drive train comprises one behind the other connected in series the following elements: an internal combustion engine, a hydrodynamic converter, a switchable clutch, an electric Machine and an automatic transmission.

Of the inventive driveline allows a Anfahrmomentüberhöhung, in particular for a heavy load approach or a permanent crawl operation under load.

Becomes the motor vehicle with open switchable coupling only powered by the electric machine, so must the hydrodynamic Transducer in the drive train according to the invention not be dragged along. This leads to an improved efficiency and a higher usable power.

Becomes the vehicle powered purely by electricity and became the internal combustion engine started for example by means of a starter or by direct start, The switchable clutch can also with a less accurate synchronization the speeds of the drive and driven side of the switchable clutch closed be because the hydrodynamic converter the speed differences balances. As a result, a faster connection of the internal combustion engine possible.

Further Advantages of the invention will become apparent from the description and the drawings out. A concrete embodiment of the invention is shown in simplified form in the drawing and in the following Description explained in more detail. Show it:

1 a schematic representation of an embodiment of a drive train according to the invention and

2 a time profile of the rotational speeds of an electric machine and an internal combustion engine during a starting process.

This in 1 illustrated embodiment of a drive train according to the invention shows successively connected in series the following elements: an internal combustion engine 1 , a hydrodynamic converter 2 , a switchable clutch 3 , an electric machine 4 and an automatic transmission 5 ,

Here is the internal combustion engine 1 directly over a wave 6a on the drive side with the hydrodynamic converter 2 positively connected. On the output side is the hydrodynamic converter 2 over a wave 6b directly with the drive side of the switchable coupling 3 connected. The switchable clutch 3 in turn, there is a shaft on the output side 6c directly with the transmission input of the automatic transmission 5 connected.

The hydrodynamic converter 2 is a lock-up clutch 2a assigned. Optionally, not shown, on the drive side in front of the converter 2 with lockup clutch 2a arranged a torsion damper.

The electric machine 4 has a stator 4a and a rotor 4b on, with the rotor 4b with the wave 6c is frictionally connected, so that the electric machine 4 in motor operation, a moment on the shaft 6c can transmit or a moment from the shaft 6c can record, if the electric machine 4 is operated as a generator. An embodiment of the electric machine 4 as external rotor is also possible.

The internal combustion engine 1 is a starter 7 assigned.

The internal combustion engine 1 can be designed for example as a diesel or gasoline engine.

In the internal combustion engine 1 it can also be a direct-starting internal combustion engine. A directly startable internal combustion engine, for example an engine with gasoline direct injection, is characterized in that it starts alone by means of deliberately used injection and ignition and thus does not require any support for a starter or another electric machine for starting. In this case can also apply to a starter 7 be waived.

In a starter-assisted, not always directly startable internal combustion engine 1 This is an optimized starter 7 assigned, by means of which a starterunterstützter direct start can be performed.

The electric machine 4 is electrical, represented by the dashed line, with a corresponding power electronics and a power source 8th , For example, a high-voltage battery connected.

Is the shiftable clutch 3 open, the drive train is so separated that the hydrodynamic converter 2 and the internal combustion engine 1 on one side of the clutch are not connected to the output. The electric machine 4 and the automatic transmission 5 on the other side are so alone connected to the output.

The switchable clutch 3 is open in particular during a vehicle standstill before a startup. The start from standstill then takes place purely electrically by the moment of the electric machine 4 ,

Such a starting process or the speed n _{E of} the electric machine 4 and the speed n _{VM of} the internal combustion engine 1 are in 2 shown over the time t.

At the beginning of the starting process at time t ₀ , the vehicle is purely electrically by the electric machine 4 powered (e-drive).

At time t ₁ , the internal combustion engine 1 started by the alternatives described above.

Is the speed n _{VM of} the internal combustion engine 1 a value whose difference Δn to the speed n _{E of} the electric machine 4 reaches a predetermined value .DELTA.n ₁ , so the switchable clutch 3 closed. This is done by way of example in the time domain .DELTA.t of 2 , Here, the speed difference .DELTA.n is advantageous by the hydrodynamic converter 2 balanced until by closing the hydrodynamic converter 2 associated bridging clutch at time t _{2 of} the direct power flow from the engine 1 to the automatic transmission 5 is made without jerking. After that, the vehicle is powered by the internal combustion engine 1 and the electric machine 4 driven together (E + VM drive).

Such a switching operation of the switchable coupling 3 is particularly comfortable and jerk-free and is further characterized by the fact that the speed difference Δn when closing the switchable clutch 3 can be larger than if no hydrodynamic converter 2 between internal combustion engine 1 and electric machine 4 would be arranged.

The start of the internal combustion engine 1 and the above-mentioned closing the switchable coupling 3 do not affect the drive torque of the vehicle.

Similarly, the vehicle can only by the internal combustion engine 1 be driven, the electric machine 4 does not pick up a moment or is operated as a generator.

Through the hydrodynamic converter 2 can only by the internal combustion engine 1 be approached.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102004045269 A1 [0002]

Claims (5)

Drive train for a motor vehicle with an internal combustion engine ( 1 ), a switchable coupling ( 3 ) and an electric machine ( 4 ), characterized in that the driveline further comprises a hydrodynamic transducer ( 2 ) and an automatic transmission ( 5 ), wherein the switchable coupling ( 3 ) separates the drive train such that the hydrodynamic converter ( 2 ) and the internal combustion engine ( 1 ) on one side and the electric machine ( 4 ) and the automatic transmission ( 5 ) on the other side. Drive train according to claim 1, characterized in that the internal combustion engine ( 1 ) over a wave ( 6a ) with the hydrodynamic converter ( 2 ) is directly connected. Drive train according to one of the preceding claims, characterized in that the electric machine ( 4 ) over a wave ( 6c ) with the automatic transmission ( 5 ) is directly connected. Drive train according to one of the preceding claims, characterized in that the internal combustion engine ( 1 ) a starter ( 7 ) assigned. Drive train according to one of the preceding claims, characterized in that the shiftable clutch ( 3 ) is controllable such that at normal power requirement with open switchable coupling ( 3 ) by means of the electric machine ( 4 ) and the automatic transmission ( 5 ) is approached and at higher power requirements with closed switchable coupling ( 3 ) by means of the internal combustion engine ( 1 ) alone or in addition to the electric machine ( 4 ) is approached.