Patent Application
20080000746
The invention will now be described, by way of example, with reference to the accompanying drawings in which:
In a schematic form represented as a block diagram,
The shift element device 6, between the combustion engine 2 and the electric motor 3, comprises a hydraulic coupling device 6A with a speed-dependent characteristic and a frictional shift element 6B, which is arranged in a power branch of the parallel hybrid drivetrain 1 that runs parallel to the hydraulic coupling element 6A, whose transmission capacity is continuously adjustable and by way of which the hydraulic coupling element 6A can be bridged. Furthermore, a coupling element side of the hydraulic coupling element 6A is in active connection with the electric motor 3, via a free-wheel overrunning connection 8. The active connection between the coupling element and the electric motor 3 or a transmission input shaft 9 of the transmission device 7, via the free-wheel overrunning connection 8, disengages when the speed of the coupling element side of the coupling element 6A, associated with the electric motor, is smaller than the speed of the electric motor 3 or the transmission input shaft 9 in the area of the free-wheel overrunning connection 8.
This means that the coupling element 6A can essentially only transfer a drive torque from the combustion engine 2 in the direction of the drive output 5, and when the parallel hybrid drivetrain 1 is in thrust operation, a torque from the combustion engine 2 can only be transferred if the transmission capacity of the frictional shift element 6B of the shift element device 6, between the combustion engine and the electric motor, is appropriate. In addition, a drive torque produced by the electric motor, during its operation in the motor mode, can only be transferred from the frictional shift element 6B to the combustion engine 2, for example, during an electric motor powered starting operation of the combustion engine 2, whereas a drive torque from the combustion engine, during traction operation of the parallel hybrid drivetrain 1, can be passed to the transmission input shaft 9, via the free-wheel overrunning connection 8, regardless of the transmission capacity of the frictional shift element at the time.
In this case, the hydraulic coupling element 6A is made as a so-termed Föttinger clutch although it is, of course, within the capability of a person with knowledge of the field to also make the coupling element 6A as a hydrodynamic torque converter or as a hydraulic clutch of some other type.
The shift element device 7, arranged between the electric motor 3 and the drive output 5 in the example embodiment of a parallel hybrid drivetrain 1 shown in
In the present case, a main transmission pump device 10 can be driven both by the transmission input shaft 9 and by a further electric motor 11. For this, the transmission input shaft 9 is actively connected to the main transmission pump device 10 or a pump impeller wheel, via another free-wheel overrunning connection 12, such that the other free-wheel overrunning connection 12 disengages when the speed of the pump impeller wheel of the main transmission pump device 10 is higher than the speed of the transmission input shaft 9. By way of the further electric motor 11, it is also possible to drive a part of the main transmission pump device 10 that must be driven in order for the main transmission pump device 10 to carry out its pumping function, so that even if the transmission input shaft 9 is at rest, the further electric motor 11 can power the main transmission pump device 10 to produce a control pressure for the shift elements of the transmission device 7 and for the frictional shift element 6B. A further free-wheel overrunning connection 12, between the transmission input shaft 9 and the main transmission pump 10, prevents any torque from being transferred from the further electric motor 11 to the transmission input shaft 9.
The further electric motor 11 is preferably a compact EC motor which can be made in the form of a space-saving plug-in unit, whereas the main transmission pump device is a mechanical oil pump optimized for efficiency, in relation to the diameter/width ratio of the pump, for the diameter of the transmission input shaft.
By way of the fact that the main transmission pump device 10 is in active connection both with the transmission input shaft 9 and with the further electric motor 11, the power availability of the vehicle is better compared with that provided by conventional drivetrain arrangements. This improvement comes into its own particularly in the event of a failure of the electric drive of the main transmission pump device 10, while there is still available energy in an electric accumulator associated with the electric motor 3 (not represented in the drawing), since the main transmission pump device 10 can be driven by the electric motor 3, via the transmission input shaft 9 so that the transmission device 4 and the frictional shift element 6B can be acted upon by a control pressure. In a simple manner, this enables, by adjusting the frictional shift element 6B, adjustment of a transmission capacity such that an emergency start of the combustion engine 2 is possible by the electric motor 3 and, in the transmission device 4, allows corresponding control of the transmission-internal shift elements, as required, for an emergency start of the vehicle.
In the spans between the combustion engine 2 and the frictional shift element 6B and between the frictional shift element 6B and the electric motor 3, the parallel hybrid drivetrain 1 of
In this case, both the frictional shift element 6B and the torsion damping elements 13A and 13B are integrated in a housing of the hydraulic coupling element 6A and form a module with it, which can be fitted, when assembling the parallel hybrid drivetrain, during an assembly step, into the housing of the transmission device 4 in a structural space close to the electric motor and the main transmission pump device 10. Depending on the intended application, the free-wheel overrunning connection 8 can be arranged, between the hydraulic coupling element 6A and the transmission input shaft 9 or the electric motor 3, either inside or outside the housing of the hydraulic or hydrodynamic coupling element 6A.
A third embodiment of the inventive parallel hybrid drivetrain 1 is shown in
Moreover, the shift element device 7, between the electric motor 3 and the drive output 5, is made as a frictional shift element located upstream from the transmission device 4, which is arranged in a structural space surrounded by the electric motor.
In contrast to the transmission-internal configuration of the shift element device 7, between the electric motor 3 and the drive output 5, the transmission-external arrangement of the shift element device 7 is subject to less restrictions in relation to its design as a slipping clutch during a starting process of the combustion engine and, in principle, shows gear- and shift-independent behavior during a process of starting the combustion engine. In addition, in principle, a process of starting the combustion engine, while a vehicle is driving in reverse, can be carried out by the same procedure as during a process of starting the combustion engine while the vehicle is driving forward where, with a transmission-internal arrangement of the shift element device 7, between the electric motor 3 and the drive output 5, the latter aspect demands additional design measures for its adoption.
In the present case, the further pump device 14 makes it possible to maintain a control pressure level in the hydraulic system of the transmission device 4, which is required for a purely electric-machine-powered starting process. This can be done with a low-power electric motor 15. Once the hybrid vehicle, made with the parallel hybrid drivetrain 1 according to
As the parallel hybrid drivetrain 1 of
A fifth embodiment of a parallel hybrid drivetrain or drivetrain arrangement 1 made in accordance with the invention, shown in
In a sixth embodiment of a parallel hybrid drivetrain or drivetrain arrangement 1, according to the invention shown in
In a simple manner, this makes it possible to drive the main transmission pump device 10, in this case, made as an internal geared pump with dual free-wheel overrunning connection, respectively, at the higher speed of the combustion engine 2 or that of a turbine of the hydraulic coupling element 6A and with the coupling element side connected to the transmission input shaft 9. In addition. a transmission ratio step can be provided between one of the couplings of the oil pump.
In a further development of the parallel hybrid drivetrain 1 of
The shift element devices 6 and 7, respectively, between the combustion engine 2 and the electric motor 3 and between the latter and the drive output 5, can be made as dry clutches or as wet-running clutches that can be operated with slip for long periods, depending on the intended application in each case.
In all the embodiments of the inventive drivetrain arrangement 1, according to the invention represented in the drawings, the electric motor 3, the hydraulic coupling element 6A and the frictional shift element 6B of the shift element device 6, between the combustion engine 2 and the electric motor 3, are arranged in a common cooling circuit, preferably with the electric motor 3 upstream in the cooling circuit relative to the hydrodynamic coupling element 6A and the frictional shift element 6B. After flowing through the frictional shift element 6B, the cooling medium circulating in the cooling circuit can be passed into a fluid reservoir, preferably an oil sump of the transmission device 4, where the cooling circuit of the main transmission pump device 10 is supplied.
Furthermore, with a drivetrain arrangement formed, in principle, the same final assembly concept can be used as in the case of conventional drivetrain concepts comprising an engine/transmission connection with a hydrodynamic torque converter so that, for the construction of a drivetrain arrangement according to the invention, by production processes already in use, only slight changes need be made to the sequence concerned.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 030 040.8 | Jun 2006 | DE | national |
