Electric vehicle propulsion system

Abstract

An electric vehicle propulsion system (1) comprises: a first electric propulsion motor (10) comprising a stator and a rotor, the rotor having a first output shaft capable of rotationally moving about a first axis, a second electric propulsion motor (11) comprising a stator and a rotor, the rotor having a second output shaft capable of rotationally moving about a second axis, a first reduction gearbox (21) which is capable of receiving torque provided by the first electric motor (10) via a first selective or non-selective coupling system (20), the first reduction gearbox (21) having a first reduction ratio, a second reduction gearbox (23) which is capable of receiving torque provided by the second electric motor (11) via a second selective or non-selective coupling system (22), the second reduction gearbox (23) having a second reduction ratio, and a third coupling system (35) for coupling the first output shaft to the second output shaft, which may be selective or non-selective, the first axis and the second axis not coinciding.

Description

Technical Field

[0001] The present invention relates to a propulsion system for an electric vehicle having a purely electric propulsion system and no internal combustion engine for propulsion.

[0002] In particular, the invention relates to a propulsion system for an electric vehicle comprising two different electric motors and two different speed reducers, so as to be able to offer a plurality of different operating modes to the user of the vehicle. Background Art

[0003] Such a propulsion system is known, for example, from Utility Model Certificate FR 2976142. The propulsion system according to this utility model certificate provides four different operating modes, namely: (i) operating with the first electric motor alone at the gear ratio of the first reducer, (ii) operating with the second electric motor alone at the gear ratio of the second reducer, (iii) operating with both electric motors at the gear ratio of the first reducer, and (iv) operating with both electric motors at the gear ratio of the second reducer. The system according to Utility Model Certificate FR 2976142 provides electric motors whose output shafts are axially continuous with one another. Such a propulsion system is limited by this alignment of the output shafts, as it presupposes a sufficiently large space to accommodate the electric motors.

[0004] A propulsion system similar to that disclosed in FR 2 976 142 is also known from application JP 2011-033077.

[0005] There remains a need for further improvements in electric vehicle propulsion systems having two electric motors and two speed reducers. Summary of the Invention

[0006] The present invention aims to meet this need and, according to one aspect thereof, does so using a propulsion system for an electric vehicle comprising:

[0007] - a first electric propulsion motor comprising a stator and a rotor having a first output shaft rotatable about a first axis,

[0008] - a second electric propulsion motor comprising a stator and a rotor having a second output shaft rotatable about a second axis,

[0009] at least a first reduction gear capable of receiving the torque provided by the first electric motor, suitably via a first selective or non-selective coupling system, this first reduction gear having a first reduction ratio,

[0010] at least a second reduction gear capable of receiving the torque provided by the second electric motor, suitably via a second selective or non-selective coupling system, this second reduction gear having a second reduction ratio,

[0011] a third coupling system for coupling the first output shaft and the second output shaft, which may or may not be selective,

[0012] The first axis and the second axis do not coincide.

[0013] The fact that the first and second output shafts are not aligned, viewed axially, makes it possible to install the propulsion system in a smaller space.

[0014] Within the meaning of this application:

[0015] - the coupling system coupling the two components is selective when it allows coupling or uncoupling the two components according to received commands,

[0016] - a coupling system that connects two components and is not selective in that it permanently connects the two components,

[0017] - two components coupled by one of the aforementioned coupling systems are fixed to each other so that they rotate together. In the case of a dog clutch as the coupling system, this fixing may correspond to a torque lock, while in the case of a clutch as the coupling system, this fixing may be a friction transmission, and

[0018] - "Upstream" and "downstream" are defined with respect to the direction of torque transmission from the electric motor towards the vehicle wheels.

[0019] The first rotation axis and the second rotation axis may be parallel. In a variant, the two rotation axes are intersecting.

[0020] The first reduction gear may be connected to the first output shaft of the first electric motor via a first selective or non-selective coupling system. This arrangement of the first reduction gear relative to the first coupling system makes it possible to limit the amount of torque that must be transmitted by the first coupling system, thereby reducing the volume and / or weight and / or cost of the first coupling system.

[0021] In a variant, the first selective or non-selective coupling system is connected to the first output shaft of the first electric motor via a first reduction gear.

[0022] The second reduction gear can be connected to the second output shaft of the second electric motor via a second coupling system. In a similar manner to that mentioned with reference to the first coupling system, positioning the second coupling system upstream of the second reduction gear makes it possible to limit the value of the torque that this second coupling system must transmit.

[0023] As a variant, the second coupling system is connected to the second output shaft of the second electric motor via a second reduction gear.

[0024] Throughout the above, the first reducer may be a single reducer and the second reducer may be a single reducer.The ratio between the first reduction gear ratio and the second reduction gear ratio may be between 1 and 5, in particular between 1.1 and 3.

[0025] In the case of a propulsion system with a single first reducer, the propulsion system can include a selection member for selecting the first reducer, thereby allowing it to be selectively coupled to the rest of the propulsion system. When the first coupling system connects the first reducer to the first output shaft of the first electric motor and the first reducer is disconnected from the first output shaft, this selection member prevents the first reducer from being driven from the downstream side. This means that the first reducer can be completely disconnected. Where appropriate, this selection member can be present even without the first coupling system. Therefore, by eliminating the first coupling system, the cost of the propulsion system can be reduced.

[0026] In the case of a propulsion system with a single second reducer, the propulsion system can include a selection member for selecting the second reducer, thereby allowing it to be selectively coupled to the rest of the propulsion system. When the second decoupling system connects the second reducer to the second output shaft of the second electric motor, and the second reducer is decoupled from the second output shaft, this selection member makes it possible to avoid driving the second reducer from the downstream side, from the perspective of the path followed by the torque. This means that the second reducer can be completely decoupled. Where appropriate, this selection member can be present even without the second coupling system. Therefore, the cost of the propulsion system can be reduced by eliminating the second coupling system.

[0027] As a variation, a plurality of first reducers, in particular two first reducers, may be arranged in parallel, wherein the first reduction gear ratios of the respective first reducers are different from each other, and / or a plurality of second reducers, in particular two second reducers, may be arranged in parallel, wherein the second reduction gear ratios of the respective second reducers are different from each other. The number of first reducers may be the same as or different from the number of second reducers.

[0028] When there are a plurality of first speed reducers in parallel, a means for selecting one of these first speed reducers may be provided so as to select the first speed reducer having the most appropriate first reduction gear ratio.

[0029] When there are a plurality of second speed reducers in parallel, a means for selecting one of the second speed reducers may be provided so as to select the second speed reducer having the most appropriate second reduction gear ratio.

[0030] In the case of a propulsion system having a plurality of first speed reducers and / or a plurality of second speed reducers, the first coupling system and the second coupling system may be omitted if appropriate, and the selection member alone performs the selective coupling function.

[0031] In the case of a plurality of first reducers and a plurality of second reducers, the ratio between the highest reduction gear ratio and the lowest reduction gear ratio considered in all first and second reducers can be between 1 and 5, in particular between 1.1 and 3.

[0032] When the two first speed reducers are in parallel and the two second speed reducers are in parallel, a propulsion system with four different transmission ratios can be obtained.

[0033] Each coupling system adopts clutch for example. The selection of clutch makes it possible to adopt progressive coupling and separation.

[0034] When the first and second coupling systems employ clutches, the first and second coupling systems may be grouped together within a dry double clutch or a wet double clutch.

[0035] In a variant, each coupling system may be of another type, for example employing a dog clutch or another system. In yet another variant, the coupling systems may be of different types compared to each other.

[0036] The first and second coupling systems employ clutches, for example, while the third coupling system employs a dog clutch, or the third coupling system is not selective.

[0037] In yet another variation, the first and second coupling systems employ dog ​​clutches, while the third coupling system employs, for example, a clutch or dog clutch or a non-selective coupling system.

[0038] Regardless of whether the first and second coupling systems utilize clutches or dog clutches, the third coupling system may be selected from:

[0039] - an assembly consisting of: a pinion fixed for integral rotation with the output shaft of one of the two electric motors and meshing with a first idler pinion mounted so as to rotate freely on an intermediate shaft; a pinion fixed for integral rotation with the output shaft of the other of the two electric motors and meshing with a second pinion fixed for integral rotation with the intermediate shaft; and a coupling member for selectively or non-selectively coupling the first pinion and the second pinion, the coupling member being, for example, a dog clutch, or

[0040] - an assembly consisting of an idler pinion mounted so as to be freely rotatable on the output shaft of one of the two electric motors, the idler pinion meshing with a first pinion fixed for integral rotation with the intermediate shaft; a pinion fixed for integral rotation with the output shaft of the other of the two electric motors and meshing with a second pinion fixed for integral rotation with the intermediate shaft; and a coupling member for selectively coupling the idler pinion and the output shaft of the electric motor, the idler pinion being mounted on the output shaft, the coupling member being, for example, a dog clutch, or

[0041] - an assembly consisting of an idler sprocket gear mounted so as to be freely rotatable on the output shaft of one of the two electric motors, the sprocket gear being engaged with a chain; a sprocket gear fixed so as to rotate integrally with the output shaft of the other of the two electric motors and being engaged with the chain; and a coupling member for selectively coupling the idler sprocket gear with the output shaft of the electric motor, the idler sprocket gear being mounted on the output shaft, the coupling member being, for example, a dog clutch, or

[0042] An assembly consisting of a sprocket gear fixed for integral rotation with the output shaft of a first electric motor; a sprocket gear fixed for integral rotation with the output shaft of a second electric motor; and a chain meshing with each of these sprocket gears. No selective coupling element is provided; the third coupling system is not selective in this latter variant.

[0043] As another variant, the third coupling system may be a permanent rigid connection, the first output shaft being fixed directly to the second output shaft, for example.

[0044] Throughout the above, the propulsion system may include a differential arranged to receive at least one of the following: the torque transmitted by the first reduction gear and the torque transmitted by the second reduction gear. The differential may be a mechanical differential or an electronic differential that controls the drive torque fed to each driven wheel of the vehicle.

[0045] Where appropriate, one or more intermediate gears may be positioned downstream of each of the first and second speed reducers and upstream of the differential. These gears are common to both the path of torque transmitted through the first speed reducer and the path of torque transmitted through the second speed reducer, and may or may not form an additional reduction gear ratio. In one variation, no additional gears are positioned between the first speed reducer and the differential, or between the second speed reducer and the differential.

[0046] Throughout the above, when the propulsion system includes three coupling systems, the propulsion system may further include a control member for controlling the first, second and third coupling systems, so that the system may adopt all or some of the following configurations:

[0047] - a configuration in which the differential receives a torque transmitted via a first reduction gear, the torque being generated by a first electric motor,

[0048] - a configuration in which the differential receives a torque transmitted via a second reduction gear, the torque being generated by a second electric motor,

[0049] - a configuration in which the differential receives a torque transmitted through a first reduction gear, the torque being generated by a first electric motor, and also receives a torque transmitted through a second reduction gear, the torque being generated by a second electric motor,

[0050] - a configuration in which the differential receives a torque transmitted via the first reduction gear, this torque being generated by the first electric motor and the second electric motor, or, where appropriate, only by the second electric motor,

[0051] - a configuration in which the differential receives a torque transmitted via the second reduction gear, the torque being generated by the first electric motor and the second electric motor, or, where appropriate, only by the first electric motor, and

[0052] - Parking brake configuration with three coupling systems in coupled configuration.

[0053] When there is a selection member for the first speed reducer and / or when there is a selection member for the second speed reducer, the aforementioned control member can also control the selection member or these selection members.

[0054] The control component is, for example, integrated into a vehicle control unit (ECU). In one variation, the control component is integrated into a transmission control unit (TCU). As another variation, the control component can be modular, with the control modules for controlling the first and second coupling systems integrated into the TCU, while the control module for controlling the third coupling system is integrated into the ECU.

[0055] Throughout the above, the ratio between the rated torque provided by the first electric motor and the rated torque provided by the second electric motor may be between 1 and 10, for example between 1 and 4.

[0056] The first electric motor and the second electric motor are, for example, of the same type, such as wound rotor or permanent magnet synchronous motors. In a variant, they may be, for example, asynchronous motors.

[0057] Throughout the above, when the propulsion system comprises a first coupling system, a second coupling system and a third coupling system, these systems may be different from each other. The third coupling system may be formed entirely or partially by dedicated elements, i.e. by one or more elements that do not belong to either the first coupling system or the second coupling system. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The present invention may be better understood by reading the following description of non-limiting exemplary embodiments and examining the accompanying drawings, in which:

[0059] - Figure 1 is a front view of a propulsion system according to an embodiment of the present invention,

[0060] - Figure 2 Schematically depicts Figure 1 The propulsion system,

[0061] - Figures 3 to 7 yes Figure 2 A variant of

[0062] - Figure 8 depicts a clutch that can be used to create a first or second connection system, and

[0063] - Figure 9 Depicted are dog clutches that can be used to create a first, second, or third coupling system. DETAILED DESCRIPTION

[0064] Figure 1 A vehicle propulsion system 1 according to a first embodiment of the present invention is shown.

[0065] In this case, the propulsion system 1 is purely electric, which means that it does not use any internal combustion engine to drive the vehicle, in this case a car. The propulsion system 1 here comprises a first electric motor 10 and a second electric motor 11 .

[0066] The first electric motor 10 and the second electric motor 11 are, for example, permanent magnet synchronous motors. The first electric motor 10 has, for example, a rated torque of 50 Nm, and the second electric motor 11 has, for example, a rated torque of 70 Nm. Figure 1 As shown, in the example depicted, the first electric motors 10, 11 have a rotor with a first output shaft rotating about a first axis of rotation X1, while the second electric motor 11 has a rotor with a second output shaft rotating about a second axis of rotation X2. In the example depicted, the axes of rotation of the first and second electric motors are parallel, but not coincident, and the axes of rotation of the two electric motors 10 and 11 are not aligned.

[0067] In reference Figure 1 and 2 In the example described, the first output shaft is connected to a first coupling system 20, which in this case is a selective coupling system. Figure 1 and 2 The clutch is shown in the figure, but can be made in some other way, such as using a dog clutch.

[0068] This first coupling system 20 allows the first output shaft of the first electric motor 10 to be coupled to a first speed reducer 21 , which has a speed reduction ratio of approximately 12, for example.

[0069] According to the reference Figure 1 and 2 In the example described, the second output shaft of the second electric motor 11 is connected to a second coupling system 22, which in this case is a selective coupling system. Similar to the system mentioned with respect to the first coupling system 20, this system Figure 1 and 2 The clutch is shown in the figure, but can be made in some other way, such as using a dog clutch.

[0070] Figure 8 An example of a clutch is depicted, suitable for embodying the first coupling system 20 or for embodying the second coupling system 22. The clutch is in this case a plate clutch, the plates 26 being coupled under the action of a moving piston to transmit torque.

[0071] In a variant, each coupling system 20, 22 may employ a dog clutch, such as Figure 9 This coupling system allows the use of claws 27 to couple two components.

[0072] The second coupling system 22 allows the second output shaft of the second electric motor 11 to be coupled to a second reducer 23 , which has a reduction ratio of approximately 8, for example.

[0073] The present invention is not limited to positioning the first or second coupling system 20 or 22 upstream of the first reducer 21 or the second reducer 23 in the path of the torque generated by the respective motor 10 or 11. As a variant, the first or second coupling system 20 or 22 may be positioned downstream of the first reducer 21 or the second reducer 23 in the path of the torque generated by the respective motor 10 or 11.

[0074] The propulsion system 1 also comprises a differential 30. In the example considered, one or more gear wheels 32 are interposed between the first reduction gear 21 and the differential 30 and between the second reduction gear 23 and the differential 30. However, in a variant, no gear wheels may be provided.

[0075] exist Figure 1 and 2 In the example shown in FIG. 2 , the propulsion system 1 includes only a single first speed reducer 21 and only a single second speed reducer 22 , but the present invention is not limited to this case.

[0076] Therefore, if Figure 5 and 6As shown, a plurality of first speed reducers 21 may be arranged in parallel between the first shaft of the first electric motor and the differential 30 , and a plurality of second speed reducers 23 may be arranged in parallel between the second shaft of the second electric motor 11 and the differential 30 .

[0077] from Figure 5 and 6 As can be seen in the figure, the two first speed reducers 21 can be arranged in parallel, and the two second speed reducers 23 can be arranged in parallel. Like the two second speed reducers 23, the two first speed reducers 21 here have different first reduction ratios. If appropriate, a selection member 33 for selecting one of the first speed reducers 21 and a selection member 34 for selecting one of the second speed reducers 23 can be provided. In this case, each of these selection members 33 and 34 is a dog clutch.

[0078] exist Figure 5 In the example of , the first coupling system 20 and the selection member 33 are associated with the first reducer 21 , and the second coupling system 22 and the selection member 34 are associated with the second reducer 23 .

[0079] exist Figure 6 In the example of , the first coupling systems 20 and 22 are absent; the decoupling function of the reducers 21 and 23 is performed by the selection members 33 and 34 .

[0080] The selection members 33 and 34 may also be present in the case where the propulsion system comprises a single first speed reducer 21 and a single second speed reducer 22. Thus, the selection members 33, 34 allow the respective speed reducer 21, 23 to be disconnected from its downstream side.

[0081] In the example described, the differential 30 is arranged to receive:

[0082] the torque available on the first shaft of the first electric motor 10 after transmission through the first coupling system 20 (if present) and the first reduction gear 21 , and / or

[0083] In the example described, the torque available on the second output shaft of the second electric motor 11 , after transmission through the optional second coupling system 22 (if present) and the second reduction gear 23 .

[0084] Differential 30 allows torque to be transferred to wheels 31 .

[0085] like Figures 1 to 7 As shown, the first output shaft of the first electric motor 10 is coupled to the second output shaft of the second electric motor 11 . This coupling is accomplished via a third connection system 35 .

[0086] As will now be described, this third coupling system 35 can be embodied in different ways.

[0087] exist Figure 1 and 2 In the embodiment, the third coupling system 35 is an assembly formed by a sprocket gear 52 fixed so as to rotate integrally with the first output shaft of the first electric motor 10, an idler sprocket gear 54 mounted so as to be freely rotatable on the second output shaft of the second electric motor 11, and a chain 55 meshing with each of the sprocket gears 52 and 54. A dog clutch 56 is provided for selectively coupling the sprocket gear 54 to the second output shaft of the second electric motor 11.

[0088] exist Figure 3 In the embodiment, the third coupling system 35 is composed of the following components: a pinion 40 fixed to rotate integrally with the first output shaft of the first electric motor 10 and meshing with a first pinion 41 fixed to rotate integrally with the intermediate shaft 42; a pinion 43 fixed to rotate integrally with the second output shaft of the second electric motor 11 and meshing with an idling second pinion 44 mounted to rotate freely on the intermediate shaft 42; and a dog clutch 45 forming a coupling member for selectively coupling the first pinion 41 and the second pinion 44.

[0089] exist Figures 4 to 6 , which differ from each other in terms of the number of first and second speed reducers 21 and 23 and the presence or absence of first and second coupling systems 20 and 22, the third coupling system is formed by an assembly consisting of a pinion 45 fixed for integral rotation with the first output shaft of the first electric motor 10, an idler pinion 47 mounted for free rotation on the second output shaft of the second electric motor 11, a first pinion 48 fixed for integral rotation with an intermediate shaft 49 and meshing with the pinion 45, a second pinion 50 fixed for integral rotation with the intermediate shaft 49 and meshing with the pinion 47, and a dog clutch 16 that allows the pinion 47 to be selectively coupled to the second output shaft on which it is mounted. In a variant, the pinions 48, 50 and the intermediate shaft 49 may be omitted, with the idler pinion 47 directly meshing with the pinion 45.

[0090] exist Figure 7 , the third coupling system is formed of an assembly consisting of a sprocket gear 52 fixed for integral rotation with the first output shaft of the first electric motor 10, a sprocket gear 53 fixed for integral rotation with the second output shaft of the second electric motor 11, and a chain 55 meshing with each of the sprocket gears 52 and 53. No selective coupling device is provided here, and the third coupling system 35 is not selective in this case.

[0091] Other examples for embodying a selective or non-selective third coupling system are possible, such as a clutch.

[0092] In another variation, the first and second coupling systems 20 , 22 employ dog ​​clutches, and the third coupling system 35 employs a clutch.

[0093] Throughout the above, the propulsion system may also include a control member 50 for controlling the first 20, second 22, and third 35 coupling systems (when these three coupling systems are present). When there are multiple first reducers 21 and / or multiple second reducers 23, the control member 50 may also select one of the reducers by appropriately using a module dedicated to these first reducers or these second reducers, which dedicated module operates the selection member 33 or 34 as described above. As already mentioned, these selection members may have a single first reducer and a single second reducer, in which case they can be controlled by the control member 50, without necessarily having to be the first coupling system 20 and the second coupling system 22.

[0094] The control member 50 is programmed so that the propulsion system can adopt the following configurations:

[0095] - configuration (i) in which the differential 30 receives the torque transmitted through the first reduction gear 21 , the torque being generated by the first electric motor 10 ,

[0096] - configuration (ii) in which the differential 30 receives the torque transmitted via the second reduction gear 23 , the torque being generated by the second electric motor 11 ,

[0097] - configuration (iii) in which the differential 30 receives the torque transmitted through the first reduction gear 21, the torque generated by the first electric motor 10, and also receives the torque transmitted through the second reduction gear 23, the torque generated by the second electric motor 11,

[0098] - configuration (iv) in which the differential 30 receives the torque transmitted via the first reduction gear 21 , this torque being generated by the first electric motor 10 and the second electric motor 11 or, where appropriate, by the second electric motor 11 alone when the first electric motor 10 is switched off,

[0099] - configuration (v) in which the differential receives the torque transmitted via the second reduction gear 23 , this torque being generated by the first electric motor 10 and the second electric motor 11 or, where appropriate, by the first electric motor 10 alone when the second electric motor 11 is switched off, and

[0100] Configuration (vi) in which each coupling system 20 , 22 and 35 is in the coupled position.

[0101] In the table below are given the commands used by the control member 50 to control the coupling system in order to obtain the above-mentioned configurations (i) to (vi).

[0102] Configuration First connection system (20) Second connection system (22) Third connection system (35) (i) Join Separation Separation (ii) Separation Join Separation (iii) Join Join Separation (iv) Join Separation Join (v) Separation Join Join (vi) Join Join Join

[0103] Configuration (i) is suitable, for example, for low vehicle speeds with low torque demand.

[0104] Configuration (ii) is suitable, for example, for high vehicle speeds with low torque demand.

[0105] Configuration (iii) is suitable, for example, for transient speeds, such as when transitioning from one reduction ratio to another.

[0106] Configuration (iv) is suitable, for example, for low vehicle speeds with high torque demands.

[0107] Configuration (v) is suitable, for example, for high vehicle speeds with high torque demands.

[0108] Configuration (vi) is suitable, for example, for operation as a parking brake.

[0109] The present invention is not limited to the examples that have been described above.

Claims

1. A propulsion system (1) for an electric vehicle, comprising: - a first electric motor (10) comprising a stator and a rotor having a first output shaft rotatable about a first axis, - a second electric motor (11) comprising a stator and a rotor having a second output shaft rotatable about a second axis, a first reduction gear (21) suitably capable of receiving the torque provided by the first electric motor (10) via a first selective or non-selective coupling system (20), the first reduction gear (21) having a first reduction ratio, a second reduction gear (23) suitably capable of receiving the torque provided by the second electric motor (11) via a second selective or non-selective coupling system (22), the second reduction gear (23) having a second reduction ratio, - a third coupling system (35) for coupling the first output shaft to the second output shaft, which may or may not be selective, The first axis and the second axis do not coincide, The propulsion system (1) does not include an internal combustion engine. The first speed reducer (21) is connected to the first output shaft of the first electric motor (10) via a first selective or non-selective coupling system (20), The second reduction gear (23) is connected to the second shaft of the second electric motor (11) via a second selective or non-selective coupling system (22), The propulsion system (1) comprises a differential (30) arranged to receive at least one of the following: a torque transmitted through the first reducer (21) and a torque transmitted through the second reducer (23), The propulsion system (1) comprises a control member (50) for controlling the first selective or non-selective coupling system (20), the second selective or non-selective coupling system (22) and the third coupling system (35) so that the propulsion system (1) can adopt at least one of the following two configurations: - configuration (iv) in which the differential receives a torque transmitted via the first reduction gear (21), the torque being generated by the first electric motor (10) and the second electric motor (11), or, where appropriate, only by the second electric motor (11), - Configuration (v) in which the differential (30) receives the torque transmitted via the second reduction gear (23), which is generated by the first electric motor (10) and the second electric motor (11), or, where appropriate, only by the first electric motor (10).

2. The propulsion system of claim 1, wherein: The first axis and the second axis are parallel.

3. The system of claim 1 or 2, wherein each of the first selective or non-selective coupling system (20), the second selective or non-selective coupling system (22) and the third coupling system (35) employs a clutch.

4. The system of claim 1 or 2, wherein the first selective or non-selective coupling system (20) and the second selective or non-selective coupling system (22) are clutches, and The third coupling system (35) adopts a dog clutch or is non-selective.

5. The system of claim 1 or 2, wherein the first selective or non-selective coupling system (20) and the second selective or non-selective coupling system (22) are dog clutches, and The third coupling system (35) adopts a dog clutch or is non-selective.

6. The system of claim 1 or 2, wherein: The control member (50) is configured to control the first selective or non-selective coupling system (20), the second selective or non-selective coupling system (22) and the third coupling system (35) so that the propulsion system (1) can also adopt all or some of the following configurations: - configuration (i), wherein the differential (30) receives torque transmitted through the first reduction gear (21), the torque being generated by the first electric motor (10), - configuration (ii), wherein the differential (30) receives torque transmitted through the second speed reducer (23), the torque being generated by the second electric motor (11), - Configuration (iii), wherein the differential (30) receives torque transmitted through the first speed reducer (21), the torque being generated by the first electric motor (10), and also receives torque transmitted through the second speed reducer (23), the torque being generated by the second electric motor (11), and - Parking brake configuration (vi) wherein the three coupling systems are in coupled configuration.

7. The system as described in claim 1 or 2, wherein a plurality of first reducers (21) are arranged in parallel, wherein the first reduction transmission ratios of each first reducer (21) are different from each other, and / or a plurality of second reducers (23) are arranged in parallel, wherein the second reduction transmission ratios of each second reducer are different from each other.

8. The system as described in claim 1 or 2, wherein two first reducers (21) are arranged in parallel, wherein the first reduction transmission ratios of each first reducer (21) are different from each other, and / or two second reducers (23) are arranged in parallel, wherein the second reduction transmission ratios of each second reducer are different from each other.

9. The system of claim 1 or 2, said third coupling system (35) comprising at least one element belonging neither to said first selective or non-selective coupling system (20) nor to said second selective or non-selective coupling system (22).

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