Motor vehicle comprising a turbo engine equipped with a generator and a reduction gear, and method based on such a vehicle

Abstract

The invention relates to a motor vehicle comprising a turbo engine which comprises: - at least one turbine and / or at least one compressor, arranged on a working axis, - an electric generator rotatably coupled to the working axis, characterised in that the turbo engine further comprises a reduction gear on the working axis. The invention further relates to a manufacturing method based on such a vehicle.

Description

DESCRIPTION TITLE OF THE INVENTION: MOTOR VEHICLE COMPRISING A TURBOACHINE EQUIPPED WITH A GENERATOR AND A REDUCTION GEAR AND A METHOD BASED ON SUCH A VEHICLE

[0001] The present invention claims priority from French application No. 2210910 filed on 21.10.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] The invention relates to the field of gas turbine cycle type turbogenerator devices and systems, integrated into a vehicle.

[0003] Gas turbine-type power converters are currently being extensively studied as range extenders in production hybrid vehicles. This converter can operate in APU (Auxiliary Power Unit) mode, where its role is to recharge the batteries of an electric vehicle. It is thus mechanically decoupled from the powertrain and operates at its maximum efficiency.

[0004] Several cycles are under investigation, including simple regenerative cycles (RGT for Regenerative Gas Turbine), but also regenerative cycles with a cooler (IRGT) and cycles with a cooler, recuperator and reheat or "Intercooled Regenerative Reheat Gas Turbine" in English.

[0005] The gas turbine cycle with cooler, recuperator, and reheat (IRReGT) is a cycle with strong potential for automotive applications. This cycle allows for high efficiency as well as high power density (high specific net work).

[0006] Integrating a turbogenerator into an electric vehicle presents challenges. Indeed, the engine speed of turbomachines is generally very high, often exceeding 100,000 RPM. Converting the turbomachine's rotation into electrical energy requires a specific electric motor.

[0007] Furthermore, this integration requires the use of a specific power electronics system, which is not readily available, to handle the high frequency and produce a ripple at a voltage acceptable to the vehicle's battery.

[0008] Thus, one objective of the invention is to remedy the defects of the prior art and to propose a solution enabling the use of a conventional electrical machine on a turbine of a turbocharger so as to convert the energy of the turbine's rotations into electrical energy.

[0009] To achieve this objective, the invention proposes a motor vehicle comprising a turbomachine which includes: - at least one turbine and / or at least one compressor, arranged on a working axis, - an electric generator rotationally coupled to the working axis, characterized in that the turbomachine further comprises a reducer on the working axis.

[0010] Advantageously, the invention offers a turbogenerator with a high-speed friction reduction system. This reduction gear is integrated into the turbogenerator at the turbomachinery level, which makes it possible to reduce the rotational speed and consequently use a conventional electrical machine and, above all, expensive conventional power electronics.

[0011] The invention also applies to other technical fields where a high-speed reducer is required.

[0012] Furthermore, the invention makes it possible to reduce the output speed of the turbomachine and to couple it to a low-speed electric machine.

[0013] This proposal is valid for all turbomachines regardless of their architecture: GT (simple Gas Turbine), RGT (Recuperative Gas Turbine), IRGT (Intercooled Recuperative Gas Turbine), IRReGT (Intercooled Recuperative Reheat Gas Turbine), etc...

[0014] According to one variant, the said reducer is placed between the generator and the turbine or compressor.

[0015] This allows the speed of the working shaft to be reduced directly in the vicinity of the generator.

[0016] According to one variant, the said reducer is a planetary reducer.

[0017] This helps to limit the size of the assembly.

[0018] According to one variant, said reducer comprises a frame, a conical sun gear, a spherical planet gear, a transmission shaft, and a conical gear wheel.

[0019] This allows for a fully functional reduction system.

[0020] According to one variant, said reducer includes a first adjustable locking screw controlling the slip and stresses between the contact points at the level of the gear wheel, and the planetary gear, the first locking screw acting on the gear wheel through a tension / force sensor, and through a lever, a helical spring and a pressure piston.

[0021] This allows for easy control of the slippage and stresses. Furthermore, it reduces sensitivity to perfect non-coaxiality (misalignment error) of the gears.

[0022] According to one variant, said reducer includes a second locking screw controlling the slip and stresses at the level of the solar gear and the planetary gear, the second locking screw acting on the solar gear through a tension / force sensor, a specific lever and a bearing.

[0023] This allows for easy control of said sliding and said stresses.

[0024] According to one variant, the said bearing is of the spindle bearing type.

[0025] According to one variant, the solar gear operating at high speed transmits power and torque through the transmission shaft of the planetary gear, the gear wheel being fixed to the frame through a dog clutch, and being movable along the axial direction following the working axis.

[0026] The invention further relates to a method for manufacturing a turbomachine for a motor vehicle according to the invention, characterized in that it comprises the following steps: - install at least one turbine and / or at least one compressor, positioned on the working axis, - an electric generator rotatically coupled to the working axis, - to rotaryly couple an electric generator to the working axis, - In addition, couple a reducer onto the working axis.

[0027] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig.1] illustrates an internal diagram of a reducer for a turbomachine of a vehicle according to a preferred embodiment; - [Fig.2] schematically illustrates a view in space of the reducer of figure 1; - [Fig. 3] schematically illustrates a first example of a turbomachine implemented in the invention; and - [Fig.4] schematically illustrates a second example of a turbomachine implemented in the invention.

[0028] The invention provides a high-speed planetary friction reducer for a turbogenerator shaft, enabling the reduction of the output shaft's rotational speed. This planetary friction reducer is designed to reduce the rotational speed of a turbomachine shaft rotating at very high speeds.

[0029] We seek to propose a reduction device that allows the rotational speed of a shaft rotating at very high speed, in particular a shaft of a turbomachine.

[0030] High-speed turbomachinery requires specific electrical machines and dedicated power electronics; the power electronics has the role of processing the high-frequency signal to obtain a signal compatible with the correct voltage required at the output level.

[0031] This device is compatible with a turbomachine, said turbomachine can be installed in an electric vehicle and allow to supply electricity to the vehicle, or in a thermal vehicle or in other possible applications such as electric generator or auxiliary power unit (APU), in particular for airplanes, boats, buses, etc.

[0032] Thus the objective of the invention is to propose this device which makes it possible to reduce the complexity of the manufacture of the turbomachine and consequently that of the vehicle.

[0033] This proposed device can be coupled to any type of turbomachine. The turbomachine can be a single or booster compressor, a two-stage compressor, a twin compressor, two or more compressors coupled on the same shaft, a single turbine, a one- or multi-stage turbine, or two or more turbines coupled together. The turbomachine can also be a simple turbocharger consisting of a compressor and a turbine, a double-stage compressor coupled to a turbine, a single compressor coupled to a double turbine, or any variant formed by the assembly of a compressor and a turbine.

[0034] Compressors and turbines can be of radial or axial technology.

[0035] The gearbox can be coupled to the turbine side (hot side) or the compressor side (cold side). The device can be coupled to the compressor side with a double compression stage, or to the compressor side with a double expansion stage.

[0036] The friction planetary reducer includes a frame 1, a sun gear 2 (or "sun gear" in English) with a conical shape, at least one planet gear 3 (or "planet gear" in English) with a spherical shape, a transmission shaft 4 (or "carrier shaft" in English), and a ring gear 5 (or "ring gear" in English) with a conical shape.

[0037] The choice of contact geometries (spherical vs conical) offers a solution that reduces sensitivity to perfect non-coaxiality (misalignment error) of gears.

[0038] The frictional contact between the sun gear 2 and the planetary gears 3 (in the preferred embodiment, there are three planetary gears 3), and between the planetary gears 3 and the gear wheel 5, is different and independent. In the illustrated embodiment, the friction angles and Hertzian pressures can be optimized independently (choice of materials, radii of curvature). Similarly, cooling can be improved.

[0039] The slippage (and stresses) between the contact points at the gear wheel 5 and the planetary gears 3 are controlled by an adjustable screw 7 which acts on the gear wheel 5 through a tension / force sensor 8, and through a lever 9, a helical spring 10 and a pressure piston 11.

[0040] Furthermore, the slippage (and stresses) at the level of the solar gear 2 and the planetary gears 3 are controlled by a screw which acts on the solar gear 2 via a tension / force sensor, a lever specific and a bearing 12, said bearing 12 being of the spindle bearing type.

[0041] The reducer can operate dry or lubricated.

[0042] In the case of operation in reduction mode, the power (torque) is transmitted from the solar gear 2, operating at high speed, through the planetary gears 3 of the transmission shaft 4. The gear wheel 5 does not rotate, it is fixed to the frame of the reducer through a kind of dog teeth connection / spline; it is mobile along the axial direction.

[0043] In the presented architecture, the reduction ratio is 10 (for a slip rate of 0). The friction contacts can be created and controlled using an active or passive system (e.g., an electric, mechanical, hydraulic, magnetic, or other actuator). This allows the friction to be adapted at any given moment according to the input-output torques (or power). The mechanism proposed in this presented architecture is equipped with a passive control mechanism.

[0044] The conical sun gear 2 is fixed by a radial bearing 6 on one side and suspended by three friction contacts with the planetary gears on the other. It is possible to use magnetic bearings (as solid segments) instead of mechanical contacts to eliminate friction (power dissipation through heating). This significantly increases the mechanical efficiency of the device.

[0045] The technical advantages are as follows: - Reduction in the cost of power electronics due to the use of a low-speed electrical machine; - the device allows the friction rate to be adapted during normal operation and according to the transmitted torque, which makes it possible to increase mechanical efficiency by controlling friction at all times; - the device is compatible with magnetic transmissions; - the device makes it possible to achieve very high reduction ratios, by adapting the diameters of the gears, preferably non-toothed.

[0046] The proposal is compatible with all thermodynamic turbocharger architectures using a heat exchanger. Below is a non-exhaustive list of these architectures: - Regenerative gas turbine architecture (RGT for "Recuperative gas turbine" in English); - Regenerative gas turbine architecture with cooled compression (IRGT) - for "Intercooled Recuperative Gas Turbine" (in English); - gas turbine architecture with cooled compression, regenerator and reheat during expansion (RReGT - for "Recuperative Reheat Gas Turbine" in English); - gas turbine architecture with cooled compression, regenerator and reheat during expansion (I RReGT - for "Intercooled Regenerative Reheat Gas Turbine" in English).

[0047] Besides the automotive field, the turbogenerator of the invention can be applied to various non-automotive applications.

Claims

CLAIMS 1. Motor vehicle comprising a turbomachine which comprises: - at least one turbine (T1) and / or at least one compressor (C1), arranged on a working axis, - an electric generator (G1) rotatably coupled to the working axis, characterized in that the turbomachine further comprises a reducer (R) on the working axis (A).

2. Motor vehicle according to claim 1, characterized in that said reducer is arranged between the generator (G1) and the turbine (T1) or the compressor (C1).

3. Motor vehicle according to any one of claims 1 to 2, characterized in that said reducer (R) is a planetary reducer.

4. Motor vehicle according to claim 3, characterized in that said reducer comprises a frame (1), a sun gear (2) of conical shape, a planetary gear (3) of spherical shape, a transmission shaft (4), and a gear wheel (5) of conical shape.

5. Motor vehicle according to claim 4, characterized in that said reducer comprises a first adjustable locking screw (7) controlling the sliding and the constraints between the contact points at the level of the gear wheel (5), and the planetary gear (3), the first locking screw (7) acting on the gear wheel (5) through a tension / force sensor (8), and through a lever (9), a helical spring (10) and a pressure piston (11).

6. Motor vehicle according to any one of claims 4 to 5, characterized in that said reducer (R) comprises a second locking screw controlling the sliding and the stresses at the level of the sun gear and the planetary gear, the second locking screw acting on the sun gear through a tension / force sensor, a specific lever and a bearing (12), 7. Motor vehicle according to claim 6, characterized in that said bearing (12) is of the spindle bearing type.

8. Motor vehicle according to any one of claims 4 to 7, characterized in that the sun gear operating at high speed, transmits the power and torque, through the transmission axis of the planetary gear, the gear wheel being secured to the frame through a dog toothing, and being movable in the axial direction along the working axis.

9. Method of manufacturing a turbomachine for a motor vehicle according to any one of claims 1 to 8, characterized in that it comprises the following steps: - install at least one turbine (T1) and / or at least one compressor (C1), arranged on the working axis, - an electric generator (G1) rotatably coupled to the working axis, - rotatably coupling an electric generator (G1) to the working axis, - additionally couple a reducer to the working axis (A).

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