FR3118729A1 - Propulsion system for a vehicle, comprising a heat engine, two electric machines and a transmission device - Google Patents

Abstract

Vehicle propulsion system, comprising a heat engine, two electric machines and a transmission device The invention relates to a vehicle propulsion system, comprising a heat engine (ICE), two electric machines (EM1 and EM2) and a transmission device. transmission (T) selectively connecting the motion outputs of said engine and said machines to a common motion output (O) of said system. System characterized in that the transmission device (T) comprises, on the one hand, two parallel power transmission lines (LT1 and LT2), each configured to kinematically connect one of the two electrical machines (EM1, EM2) to the common output (O) and each integrating, according to a series or cascade kinematic arrangement, a first, a second and a third (GS1, GS3, GS5; GS2, GS4, GS6) downstream torque transfer elements, on the other hand, two upstream selective torque transfer elements (C3 and C4), arranged and configured to connect the motion output of the heat engine (ICE) to one of the two parallel power transmission lines (LT1 and LT2) , and, finally, an intermediate torque selective transfer element (C5) connecting the two parallel power transmission lines (LT1 and LT2). Figure to be published with abstract: Fig.1

Description

Propulsion system for a vehicle, comprising a heat engine, two electric machines and a transmission device

The present invention relates to the field of motor vehicle equipment with hybrid propulsion, in particular their drive, and relates to a propulsion system for a vehicle, comprising a heat engine, two electric machines (motors) and a transmission device. By propulsion, we must of course understand the driving of the driving wheels of the vehicle, whether the latter is of the traction or propulsion type.

The applicant has already developed numerous productions of transmissions and gearboxes for hybrid vehicles, which have in particular given rise to the filing of the following French patent applications: FR 1908068, FR 2000371 and FR 2000372.

The aim of the present invention is to improve the various concepts set out in the three aforementioned patent applications, and this essentially on the following points: the cost, the mechanical efficiency, the realization of gear changes with maintenance of the transmission of torque to the wheels and the provision of a greater number of reports, without significantly increasing the complexity or the size.

The transmission solutions described and represented in the above patent applications have used an electrical machine with high torque and power operating on high voltage, which is therefore potentially expensive. They also include expensive mechanical subsystems such as planetary gear sets or wet clutches requiring the assistance of a pump and a hydro-electric control system.

Furthermore, those skilled in the art know that the efficiency of a transmission is directly impacted by three predominant factors, namely: the gear ratios, the type of connection elements and the absolute and relative speeds of the various elements of the transmission.

The different types of connecting elements frequently used are friction clutches (brake discs or bands), selectable freewheels, synchronizers, and dogs. Synchronizer or dog clutch type connections offer optimum efficiency, but have the disadvantage of not being able to transmit the torque progressively.

Thus, in the case of the use of dogs, the realization of gear changes under torque requires that at least one electric machine is linked to the wheels without going through the activation of a connection element.

Some DCT or MTA type hybrid transmissions existing on the automotive market use dog clutch or synchronizer type connections, but they have the disadvantage of stopping or reducing the transmission of torque to the wheel during gear changes (transmissions hybrids of type P2 or P3).

In connection with the issues related to the choice of the type of connection element, and knowing that the cost price of a selective torque transfer element of the mechanical clutch type (for example a dog clutch or the like) is lower than that of a synchronizer, the problem posed to the invention therefore consists in proposing a simple transmission concept, providing sufficient gear ratios and allowing the use of such selective transfer elements as connection elements, while allowing gear changes under torque ( i.e. without interruption of torque transmitted during gear changes). Particular care should also be taken, as much as possible, in the configuration and definition of the control of these dogs to optimize the number of actuators.

The object of the present invention is to solve the problem set out above.

To this end, the main object of the invention is a propulsion system for a vehicle, comprising a heat engine, two electric machines and a transmission device selectively connecting the movement outputs of said engine and of said machines to a common movement output of said system. , with the ability to establish a plurality of variable predetermined ratios and drive modes, said transmission device integrating selective torque transfer elements and torque transfer elements with gear change,
system characterized in that the transmission device comprises, on the one hand, two parallel power transmission lines, each configured to kinematically connect one of the two electric machines to the common output and each integrating, according to a kinematic arrangement in series or cascade, a first, a second and a third torque transfer element with rotational speed modification and a downstream selective torque transfer element, on the other hand, two upstream selective torque transfer elements, arranged and configured to connect the motion output of the heat engine to one or the other of said two parallel power transmission lines, and, finally, an intermediate torque selective transfer element, arranged and configured to connect the two lines together power transmission parallels.

The invention will be better understood, thanks to the description below, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the appended diagrammatic drawings, in which:

is a functional and kinematic schematic representation of a propulsion system for a vehicle according to the invention;

is a symbolic wireframe representation of one embodiment of the propulsion system as shown ;

,

,

,

illustrate the different paths (bold lines) possible for torque/power transmission in the transmission device forming part of the system represented , this depending on the engaged or active selective torque transfer elements and in the different possible operating modes of said system, namely, in thermal drive mode (FIGS. 3A to 3D), in electrical drive mode (FIGS. 4A to 4E ), in hybrid drive mode (FIGS. 5A to 5J) and in series mode (FIGS. 6A to 6D), the elements designated A to E corresponding respectively to the elements C3, C4, C5, C1 and C2 of FIGS. 1 and 2, and ,

illustrates an example of a passage matrix or interlocking table of the various selective torque transmission elements/members forming part of the transmission device according to the invention, with simultaneous indication of the designations of the speeds and of the drive/driving mode, as well as stagings (gear ratio), this for reduction ratios of the torque transfer elements (GSj) with gear change which are defined as follows: GS1=2.52; GS2=2.00; GS3=2.06; GS4=1.41; GS5=2.07; GS6=4.24.

Figures 1 to 6 schematically illustrate a propulsion system for a vehicle, comprising a thermal engine (ICE), two electric machines (EM1 and EM2) and a transmission device (T) selectively connecting the movement outputs of said engine and said machines to a common movement output (O) of said system, with the ability to establish a plurality of variable predetermined ratios and drive modes, said transmission device (T) integrating transfer elements (Ci) torque selector and torque transfer elements (GSj) with gear change.

According to the invention, this system is characterized in that the transmission device (T) comprises, on the one hand, two parallel power transmission lines (LT1 and LT2), each configured to kinematically connect one of the two electrical machines (EM1, EM2) at the common output (O) and each integrating, according to a kinematic arrangement in series or cascade, a first, a second and a third (GS1, GS3, GS5; GS2, GS4, GS6) elements of torque transfer with rotational speed modification and a downstream selective torque transfer element (C1; C2), on the other hand, two upstream selective torque transfer elements (C3 and C4), arranged and configured to connect the motion output of the heat engine (ICE) to either of said two parallel power transmission lines (LT1 and LT2), and, finally, an intermediate torque selective transfer element (C5), arranged and configured to interconnect the two parallel lines of power transmission (LT1 and LT2).

Thus, the invention proposes, in order to achieve the object set out in the invention, a propulsion system integrating, on the one hand, a transmission device (T) of the DHT type (transmission intended for hybrid vehicles), having a specific arrangement selective torque transfer elements (Ci) and torque transfer elements (GSj) with gear change (ratios greater than 1), and comprising, on the other hand, two electric machines (EM1 and EM2) capable of be low torque and low power and capable of operating at 48V or high voltage.

Advantageously, each of the downstream selective torque transfer elements (C1; C2) is arranged, in the corresponding power transmission line (LT1 and LT2), between the second (GS3; GS4) and the third (GS5; GS6) torque transfer element with modification of rotational speed of the line considered.

Preferably, the kinematic connection between the motion output of the heat engine (ICE) and one or other of said two parallel power transmission lines (LT1 and LT2), which is achieved by one or other of two upstream selective torque transfer elements (C3 and C4), is connected to the relevant line (LT1 or LT2) between the first (GS1; GS2) and the second (GS3; GS4) torque transfer elements with modification of rotational speed of said line.

As shown in particular by the , it is advantageously provided by the invention that the intermediate torque selective transfer element (C5) be arranged and configured to be able to kinematically connect the two parallel power transmission lines (LT1 and LT2) between the second (GS3 ; GS4) and the third (GS5; GS6) torque transfer elements with respective rotational speed modification of said lines (LT1 and LT2).

Additionally or alternatively, it may also be envisaged that the intermediate torque selective transfer element (C5) be arranged and configured to kinematically connect the two parallel power transmission lines (LT1 and LT2) to each other upstream of the elements (C1; C2) of selective transfer of torque downstream respectively of these lines.

In accordance with a practical embodiment of the system according to the invention and as illustrated by way of example by the , each torque transfer element (GSj) with speed change consists of a pair of mutually engaged gears having a reduction transmission ratio, and each selective torque transfer element (Ci) consists of a mechanical clutch, preferably of the dog clutch type, the various gear and dog components being mounted on parallel shafts (A1 to A5) including the movement output shafts (A1, A2, A3) of the three motors (EM1, EM2 and ICE) and the shaft (A5) and/or the member (DIFF) forming the common movement output (O).

According to a constructive variant, the components of the selective torque transfer elements (C1 and C2) downstream of the two parallel power transmission lines (LT1 and LT2) and those of the intermediate selective torque transfer element (C5), as well as the downstream gears of the second (GS3 and GS4) torque transfer elements with rotational speed modification and the upstream gears of the third (GS5; GS6) torque transfer elements with rotational speed modification of the two parallel lines of power transmission (LT1 and LT2), can be mounted on its own specific shaft (A4), the control of the two downstream selective torque transfer elements (C1 and C2) being coupled or synchronized.

According to an additional feature of the invention, the two upstream selective torque transfer elements (C3 and C4) together form a double dog clutch mounted on the heat engine (ICE) movement output shaft (A3).

Thus, in its preferred constructive variant, the invention proposes a propulsion system whose transmission device (T), preferably controlled in an entirely automatic manner, integrates six pairs of gears (GS1, GS2, GS3, GS4, GS5 and GS6 ) and five dogs (C1 to C5 in Figures 1 and 2 and A, B, C, D and E in Figures 3 to 7), respectively constituting mechanical transfer elements with gear ratios and switchable mechanical connection elements. The correspondences between the references for the (same) dogs, between figures 1 and 2, on the one hand, and figures 3 to 7, on the other hand, are established more precisely as follows: A=C3; B=C4; C=C5; D=C1; E=C2.

More specifically, a system with an (automatic) gearbox for a thermal/electric hybrid vehicle is proposed, which consists of two electric machines (EM1 and EM2), each connected to the output via a cascade of reduction ratios (GS1, GS2, GS3, GS4, GS5 or GS6) and a dog clutch (D or E). For EM1, the power transfer is done by GS1, GS3, dog clutch D (or C1) and GS5. For EM2, the transfer of power is done by GS2, GS4, the dog clutch E (or C2) and GS6. Dog C (or C5) connects the two branches or lines (LT1 and LT2) at the level of dogs D and E. The heat engine (ICE) connects to the two branches or lines via dogs A (or C3) and B (or C4) respectively at the output of the reduction gears GS1 and GS2.

This construction of the transmission device allows the system to provide:

-4 mechanical gears from the heat engine (ICE)

-2 electrical reports from the first electrical machine (EM1) and

-2 electrical reports from the second electrical machine (EM2)

Finally, the various possible combinations of these ratios make it possible to define the following driving modes, as shown in figures 3 to 6:

-4 thermal modes

-5 electric modes

-8 parallel hybrid modes

-2 serial hybrid modes

-4 serial modes

The invention also relates to a method for controlling a propulsion system as described above and which comprises in particular a heat engine (ICE), two electric machines (EM1 and EM2) and a transmission device (T) selectively connecting the movement outputs of said three motors to a common movement output (O) of said system, with the ability to establish a plurality of variable predetermined ratios and drive modes, said transmission device (T) integrating selective torque transfer elements (Ci) and torque transfer elements (GSj) with speed change.

This method is characterized in that it consists in selectively supplying, by a suitable control of the various elements (C1 to C5) of selective transfer of torque, four transmission ratios (ICE1, ICE2, ICE3, ICE4) for training in thermal, i.e. by the internal combustion engine alone (ICE), and five transmission ratios (E12, E2, E23, E3, E34) for training in electric mode, i.e. solely by at least one of the two electric machines (EM1, EM2), including three gears (E12, E23, E34) for simultaneous drive by the two electric machines (EM1 and EM2), and in that each upshift or descending for thermal drive is carried out by passing through one of said three ratios (E12, E23, E34) for simultaneous drive by the two electric machines (EM1 and EM2).

It can be seen that each mechanical ratio is associated with an electrical ratio which is common with the mechanical ratio which follows it:

ICE1 and ICE2 have E12 in common

ICE2 and ICE3 have E23 in common

ICE3 and ICE4 have E34 in common

And the method according to the invention can provide, during an upshift or downshift in thermal mode from ICEi to ICEj, by a suitable control of the selective torque transfer elements (C1 to C5) concerned, to perform the following sequence of operating phases:
-Phase 0 (initial state): thermal report ICEi,
-Phase 1: in hybrid mode, reduction to 0 of the thermal torque, supplied by the motor (ICE), and simultaneous rise in the electrical torques, supplied by the machines (EM1 and EM2),
-Phase 2: disengagement of the dog clutch (C3 or C4) connecting the motor movement output (ICE), providing thermal mode with a ratio i, to switch to electric mode Eij,
-Phase 3: in electric mode Eij, synchronization of the dog clutch speed (C3 or C4) of connection of the motor movement output (ICE), providing the thermal mode with a ratio j,
-Phase 4: engagement of said dog (C3 or C4) for connecting the motor movement output (ICE), providing the thermal mode with a ratio j,
-Phase 5: in hybrid mode, rise in the thermal torque and simultaneous drop to 0 of the electrical torques,
-Phase 6 (final state): thermal report ICEj.

Throughout this sequence, the torque transmitted to the wheels is never less than the lowest torque obtained with the ICEi and ICEj ratios, because it combines the sum of the powers of the two electric machines.

Another possible sequence for carrying out these passages consists in using the existing serial hybrid modes. It makes it possible to have a faster synchronization of the speed of the internal combustion engine (ICE) but does not make it possible to guarantee the consistency of the torque transmitted to the wheels in all the power conditions requested by the driver of the vehicle.

Gear changes from one electric mode to another are easily achieved with the temporary suspension of the torque of one of the two electric machines so as to be able to engage or disengage the dogs involved.

Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (10)

Propulsion system for a vehicle, comprising a thermal engine (ICE), two electric machines (EM1 and EM2) and a transmission device (T) selectively connecting the movement outputs of said engine and of said machines to a common movement output (O) said system, with the ability to establish a plurality of variable predetermined ratios and drive modes, said transmission device (T) integrating selective torque transfer elements (Ci) and torque transfer elements (GSj) torque with gear change,
system characterized in that the transmission device (T) comprises, on the one hand, two parallel power transmission lines (LT1 and LT2), each configured to kinematically connect one of the two electric machines (EM1, EM2) to the common output (O) and each integrating, according to a series or cascade kinematic arrangement, a first, a second and a third (GS1, GS3, GS5; GS2, GS4, GS6) torque transfer elements with speed modification of rotation and a downstream selective torque transfer element (C1; C2), on the other hand, two upstream selective torque transfer elements (C3 and C4), arranged and configured to connect the motion output of the heat engine ( ICE) to either of said two parallel power transmission lines (LT1 and LT2), and, finally, an intermediate torque selective transfer element (C5), arranged and configured to interconnect the two lines power transmission parallels (LT1 and LT 2). Propulsion system according to Claim 1, characterized in that each of the downstream selective torque transfer elements (C1; C2) is arranged, in the corresponding power transmission line (LT1 and LT2), between the second (GS3; GS4) and the third (GS5; GS6) torque transfer element with modification of the rotational speed of the line considered. Propulsion system according to either of Claims 1 and 2, characterized in that the kinematic connection between the movement output of the thermal engine (ICE) and one or the other of the said two parallel power transmission lines (LT1 and LT2) produced by one or the other of the two elements (C3 and C4) for selective transfer of torque upstream, is connected to the line concerned (LT1 or LT2) between the first (GS1; GS2) and the second (GS3; GS4) torque transfer elements with modification of rotational speed of said line. Propulsion system according to any one of Claims 1 to 3, characterized in that the intermediate torque selective transfer element (C5) is arranged and configured to kinematically connect the two parallel power transmission lines (LT1 and LT2) between the second (GS3; GS4) and third (GS5; GS6) torque transfer elements with respective rotational speed modification of said lines (LT1 and LT2). Propulsion system according to any one of Claims 1 to 3, characterized in that the intermediate torque selective transfer element (C5) is arranged and configured to kinematically connect the two parallel power transmission lines (LT1 and LT2) upstream of the selective torque transfer elements (C1; C2) respective downstream of these lines. Propulsion system according to any one of Claims 1 to 5, characterized in that each torque transfer element (GSj) with gear change consists of a pair of mutually meshing gears having a reducing transmission ratio, and in that each selective torque transfer element (Ci) consists of a mechanical clutch, preferably of the dog clutch type, the various gear and dog components being mounted on parallel shafts (A1 to A5) whose shafts (A1, A2, A3) movement output of the three motors (EM1, EM2 and ICE) and the shaft (A5) and/or the member (DIFF) forming the common movement output (O). Propulsion system according to Claim 6, characterized in that the components of the selective torque transfer elements (C1 and C2) downstream of the two parallel power transmission lines (LT1 and LT2) and those of the element (C5) selective transfer of intermediate torque, as well as the downstream gears of the second (GS3 and GS4) torque transfer elements with rotational speed modification and the upstream gears of the third (GS5; GS6) torque transfer elements with speed modification of rotation of the two parallel power transmission lines (LT1 and LT2), are mounted on a specific own shaft (A4), the control of the two downstream selective torque transfer elements (C1 and C2) being coupled or synchronized. System according to any one of Claims 1 to 6, characterized in that the two upstream selective torque transfer elements (C3 and C4) together form a double dog clutch mounted on the movement output shaft (A3) of the motor thermal (ICE). Method for controlling a propulsion system according to any one of Claims 1 to 8, this system comprising in particular a heat engine (ICE), two electric machines (EM1 and EM2) and a transmission device (T) selectively connecting the movement outputs of said three motors to a common movement output (O) of said system, with the ability to establish a plurality of variable predetermined ratios and drive modes, said transmission device (T) integrating elements (Ci ) of selective torque transfer and of the elements (GSj) of torque transfer with change of speed, method characterized in that it consists in supplying selectively, by a suitable control of the various elements (C1 to C5) of selective transfer of torque , four transmission ratios (ICE1, ICE2, ICE3, ICE4) for driving in thermal mode, that is to say by the combustion engine alone (ICE), and five transmission ratios (E12, E2, E23, E3 , E34) for a drive in electric mode, that is to say only by at least one of the two electric machines (EM1, EM2), including three gears (E12, E23, E34) for simultaneous drive by the two electric machines (EM1 and EM2), and in that each upshift or downshift for thermal drive takes place via one of said three ratios (E12, E23, E34) for simultaneous drive by the two electric machines (EM1 and EM2) . Method according to claim 9, characterized in that it consists, during an upshift or downshift in thermal mode from ICEi to ICEj, by an adapted control of the selective torque transfer elements (C1 to C5) concerned, to carry out the following sequence of operating phases:
Phase 0 (initial state): thermal report ICEi,
Phase 1: in hybrid mode, reduction to 0 of the thermal torque, supplied by the motor (ICE), and simultaneous rise in the electrical torques, supplied by the machines (EM1 and EM2),
Phase 2: disengagement of the dog (C3 or C4) connecting the motor movement output (ICE), providing thermal mode with a ratio i, to switch to electric mode Eij,
Phase 3: in electric mode Eij, synchronization of the speed of the dog clutch (C3 or C4) of connection of the motor movement output (ICE), providing the thermal mode with a ratio j,
Phase 4: engagement of said dog (C3 or C4) for connecting the motor movement output (ICE), providing the thermal mode with a ratio j,
Phase 5: in hybrid mode, rise in the thermal torque and simultaneous drop to 0 of the electrical torques,
Phase 6 (final state): ICEj thermal report.