The invention relates to a hydrodynamic assembly which comprises a hydrodynamic retarder and a hydrodynamic clutch. Such an assembly is for example used in a turbo-compound system with a retarder, and is also used in a turbo compound retarder system (TCR system). In accordance with one embodiment the invention relates to such a TCR system.
A turbo compound system (TC system) is used in the drive train, in particular of a motor vehicle, in order to use at least a part of the exhaust gas energy of an internal combustion engine for driving of the crankshaft, which is driven by the internal combustion engine. For this purpose the turbine wheel of the exhaust gas turbine arranged on a turbine shaft, said exhaust gas turbine being connected to the exhaust gas flow of the internal combustion engine, is offset in a rotation by means of the exhaust gas flow and transfers torque or turning capacity to an input shaft of a hydrodynamic clutch. This operating state is termed as exhaust gas power turbine operation and is always present when enough power output is contained in the exhaust gas flow of the internal combustion engine.
The input shaft of the hydrodynamic clutch drives a primary wheel which with a secondary wheel forms the torus shaped working chamber of the hydrodynamic clutch. Turning capacity is transferred from the primary wheel to the secondary wheel via a hydrodynamic circuit in the working chamber filled with working fluid. This turning capacity is transferred at least indirectly to the crankshaft of the internal combustion engine.
In a turbo compound retarder system a hydrodynamic retarder is additionally provided, which in the braking operation brakes the crankshaft hydrodynamically and because of this is wear-free. For this purpose the working chamber of the retarder is filled with working fluid and transfers torque from a rotor of the retarder, which has a drive connection to the crankshaft, to the stationary stator, which exercises a braking torque on the crankshaft.
In
The primary wheel 2.1 of the hydrodynamic clutch 2 is arranged opposite the secondary wheel 2.2 of the hydrodynamic clutch 2 on a first input shaft 3. The first input shaft 3 has a drive connection to the exhaust gas driven turbine (ANT) or to the turbine shaft (not shown) of the exhaust gas driven turbine (not shown). In exhaust gas power turbine operation torque is transferred via the first input shaft 3 to the primary wheel 2.1 of the hydrodynamic clutch 2. This torque or the associated turning capacity is transferred via the hydrodynamic circulation flow in the working chamber 2.3 of the hydrodynamic clutch 2 to the secondary wheel 2.2 and further via the second input shaft 4, which acts in this operating state as an output shaft, to the crankshaft.
In the braking operation exclusively the working chamber 1.3 of the hydrodynamic retarder is filled with working medium, for example oil, water or a mixture. In exhaust gas power turbine operation exclusively the working chamber 2.3 of the hydrodynamic clutch is filled with a corresponding working medium. The respective other working chamber is emptied, either completely or up to a predefined residual working medium quantity.
In the embodiment of a hydrodynamic assembly shown in
A turbo compound system with a hydrodynamic assembly in accordance with the generic term of Claim 1 is additionally shown in WO 02/070877 A1. Also in the case of this assembly two torus-shaped working chambers are carried out by means of a back to back arrangement, namely a first working chamber of a hydrodynamic retarder and a second working chamber of a hydrodynamic clutch.
With regard to further designs of combinations of hydrodynamic clutches and brakes reference is made to the following documents:
The invention is based on the object of further developing a hydrodynamic assembly of the initially described type so that at least the first described disadvantage or advantageously both described disadvantages are overcome.
The inventive object is solved by means of a hydrodynamic assembly with the features of Claim 1 and as an alternative embodiment by means of a hydrodynamic assembly in accordance with Claim 7. Further Claim 10 describes an inventive turbo compound retarder system which comprises an inventive hydrodynamic assembly.
The dependent claims describe advantageous and useful embodiments of the invention.
In accordance with the first inventive embodiment the hydrodynamic assembly exhibits, corresponding to the described hydrodynamic assembly state of the art and shown in
In accordance with the invention and in deviation to the hydrodynamic assembly represented in
In accordance with the second inventive embodiment the hydrodynamic assembly exhibits a stator of the retarder which can be moved in axial direction in place of the rotor of the retarder and secondary wheel of the clutch which can be jointly moved. The rotor and the secondary wheel are in the process held stationary in axial direction so that the primary wheel and secondary wheel of the hydrodynamic clutch are “near” one another in any operating state or arranged at a predefined distance from one another, in which in the case of the filled working chamber of the hydrodynamic clutch a circulation flow forms for torque transfer in the working chamber.
In accordance with the second inventive embodiment the stator of the retarder can be moved from a first position, in which the stator is arranged at a distance from the rotor or at a maximum axial distance from the rotor, to a second position, in which the stator is near the rotor of the retarder, that is, is arranged at a minimum axial distance opposite the rotor so that in the case of the filled working chamber of the retarder a hydrodynamic circulatory disturbance forms for transfer of braking torque.
In accordance with both embodiments a control device is advantageously provided which controls the filling and emptying of the two working chambers with working medium. The control device is in particular designed in such a way that precisely one working chamber is always filled with working medium while the other working chamber is completely or extensively, that is up to a predefined residual working medium quantity, emptied. In the process the working chamber of the hydrodynamic clutch is filled in exhaust gas power turbine operation, and in braking operation the working chamber of the hydrodynamic retarder is filled. As an alternative the control device can also control a filling and emptying of the retarder, wherein the working chamber of the hydrodynamic clutch always remains filled, in particular by means of control through the control device. Always filled also means a varying filling degree of the working chamber; that means operating states in which the working chamber of the hydrodynamic clutch is more or less filled.
The filling or emptying of the working chambers takes place in the process advantageously in dependence on the power ratio between the two input shafts of the hydrodynamic assembly. In exhaust gas power turbine operation, in which the drive power from the exhaust gas driven turbine applied on the first input shaft is greater than the drive power of the second input shaft, which is connected to the crankshaft, a power transfer should take place from the drive power turbine to the crankshaft. Correspondingly in this operating state the working chamber of the hydrodynamic clutch is filled with working medium and the primary wheel and the secondary wheel of the hydrodynamic clutch are opposite one another at a minimum axial distance. In braking operation, on the other hand, a comparably small or no drive power of the exhaust gas turbine is applied on the first input shaft, while the second input shaft continues to be driven by the crankshaft with an in comparison greater drive power. Correspondingly the rotor and the stator of the retarder are offset at a minimum axial distance to one another and the working chamber of the retarder is filled with working medium so that torque is conducted away from the crankshaft in the form of braking torque.
In accordance with the first embodiment of the inventive hydrodynamic assembly the rotor of the retarder and the secondary wheel of the clutch are advantageously rotationally borne jointly on the second input shaft, in particular by means of a hollow shaft provided with threading on the inside, limited to the second input shaft in a threaded engagement. For example the second input shaft can exhibit an external thread which is in engagement with the internal thread of the rotor and the secondary wheel. By means of this threaded engagement the rotor and the secondary wheel are arranged rotationally displaceable between the first axial position and the second axial position on the second input shaft. The direction of the thread, which can either be constructed as a right-handed thread or as a left-handed thread, is advantageously selected in such a way that the axial position of rotor and secondary wheel is automatically set in dependence on the power ratio to the first input shaft and the second input shaft or in dependence on the turning capacity ratio between the first input shaft and the second input shaft. Provided a greater turning capacity is applied on the first input shaft, which is near the exhaust gas driven turbine or has a drive connection to the exhaust gas driven turbine, than is applied on the second input shaft, which is near the crankshaft or has a drive connection to the crankshaft, the rotor and the secondary wheel travel to the first position, in which the secondary wheel is near to the primary wheel of the hydrodynamic clutch. Provided there is a greater turning capacity on the second input shaft than is on the first input shaft, the rotor and the secondary wheel travel to the second axial position, in which the rotor is near the stator. This can be achieved by means of the fact that considered from the primary wheel of the clutch in the direction of the stator of the retarder the thread is constructed screwing inward opposite to the drive utilization of the input shafts.
In accordance with a further development of the first inventive embodiment a regulating device is additionally provided, by means of which the secondary wheel of the hydrodynamic clutch and with it simultaneously the rotor of the retarder can be forced into a remote position opposite the primary wheel of the hydrodynamic clutch, and to be precise, also when a comparatively large turning capacity or a turning capacity exceeding a predefined limiting value is present on the first input shaft, said turning capacity in particular being able to be larger than the turning capacity on the second input shaft. Such a forced removal of the secondary wheel from the primary wheel predefined from the outside, for example by inputting a regulating command into the regulating device is favorable when operating states are present in braking operation in which “normally”, that is in the case of arrangement of the primary wheel and the secondary wheel at a minimum axial distance to each other, drive power would be transferred from the exhaust gas power turbine to the crankshaft, which is undesirable. By means of purposeful removal of the secondary wheel of the hydrodynamic clutch from the primary wheel in such operating states such a power transfer from the exhaust gas power turbine to the crankshaft is prevented.
The invention will be explained more closely with the help of exemplary embodiments and
The figures show the following:
In the figures corresponding components are provided with the same reference symbols. In this respect another description of the components already described in
As one recognizes in
In the first position of the rotor 1.1 and of the secondary wheel 2.2 shown in
In
On the basis of the fact that the thread 5 in the design shown in
Additionally, a servomotor (not shown) can be provided, which in the exhaust gas power turbine operation in spite of the power ratios which arise in accordance with
In
In order to lessen the frictional loss in the retarder 1, the stator 1.2 of the retarder can be axially removed from the rotor 1.1, that is, can be transported to a predefined maximum axial distance.
Of course it would also be possible to design the rotor 1.1 to be axially movable in such a way that it would be removable from the stator 1.2 in the exhaust gas power turbine operation without the axial position of the secondary wheel 2.2 simultaneously being changed. On the basis of the advantageous effect by means of a simultaneous removal of the secondary wheel 2.2 from the primary wheel 2.1 in the case of movement of the rotor 1.1 to the to the axially near position on the stator 1.2, however; the design shown in
In
Number | Date | Country | Kind |
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10 2006 013 003.0 | Mar 2006 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2007/002405 | 3/19/2007 | WO | 00 | 8/20/2009 |