Motor vehicle comprising multiaxial turbochargers coupled to an electric generator, method based on such a vehicle

Abstract

The invention relates to a motor vehicle comprising a turbogenerator system which comprises: multiaxial turbochargers comprising compressors (C1, C2) and turbines (T1, T2); a cooler (I); a recuperator (R); two combustion chambers (CC1, CC2); a turbomachine comprising so-called energetic turbines (Te1, Te2), and an electric generator (EM). The invention makes it possible to simplify the architecture by using an electric machine, and to limit congestion by separating the turbocharger axes. The invention also relates to a method based on such a vehicle.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: MOTOR VEHICLE COMPRISING MULTIAXIAL TURBOCHARGERS COUPLED TO AN ELECTRIC GENERATOR, METHOD BASED ON SUCH A VEHICLE

[0003]

[0001] The present invention claims priority from French application No. 2211550 filed on 07.11.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0004]

[0002] The invention relates to the field of gas turbine cycle type turbogenerator devices and systems for motor vehicles.

[0005]

[0003] Gas turbine type energy converters are currently being widely studied as range extenders in series hybrid vehicles.

[0006]

[0004] This converter can operate in APU mode (for Auxiliary Power Unit) 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 point.

[0007]

[0005] Several cycles are under investigation, including simple recuperative cycles (RGT for recuperative gas turbine or "Recuperative Gas Turbine"), but also recuperative cycles with cooler (IRGT) and cycles with cooler, recuperator and reheater or "Intercooled Recuperative Reheat Gas Turbine" in English).

[0008]

[0006] The cooled, recuperated, reheated gas turbine (IRReGT) cycle illustrated in Figure 1 is a cycle with high potential for automotive applications. This cycle makes it possible to achieve high efficiency but also high power density (high net specific work).

[0009]

[0007] In the IRReGT cycle, two electric machines may be needed. Indeed, one can have a single electric machine, but in this case, it is necessary to put the two e-turbomachines (electrified turbomachine, namely a compressor, a turbine and an electric machine) on the same axis. However, in this case, the axis of the turbomachine becomes long and there will be hot inlets / outlets on both sides of the turbogenerator.

[0008] The solution of having two separate e-turbomachines is interesting but this implies the use of two electric machines and consequently the use of two power electronics, which complicates the system.

[0010]

[0009] Patent application US 2002 / 0152754 A1 proposes to put a turbine coupled with a generator. The problem is that at the outlet of the turbine of the second turbocharger, there is no turbine coupled to the generator allowing for additional expansion. From a thermodynamic point of view, the work of the turbine of the second turbocharger is used to drive the second compressor but there will be no additional net work. Thermodynamically, this has no impact on efficiency. The only impact will be the increase in pressure in the recuperator and the combustion chamber, which makes it possible to reduce the size of these components.

[0011]

[0010] An objective of the present invention is to remedy the defects of the prior art, and in particular to propose an architecture limiting the complexity of mounting power electronics, while having better efficiency than in the prior art.

[0012]

[0011] To achieve this objective, the invention proposes a motor vehicle comprising a turbogenerator system having a fluid circuit from an upstream to a downstream, the turbogenerator system comprising:

[0013] - a first turbocharger comprising a first compressor and a first turbine on a first axis;

[0014] - a second turbocharger comprising a second compressor and a second turbine on a second axis;

[0015] - a cooler in fluid communication with the first compressor upstream, and with the second compressor downstream;

[0016] - a recuperator in fluid communication with the second upstream compressor;

[0017] - a first combustion chamber in fluid communication with the upstream recuperator, and with the second turbine downstream;

[0018] - a turbomachine comprising a first and a second energy turbine, and an electric generator on a third axis, the first energy turbine being in fluid communication with the second upstream turbine;

[0019] - a second combustion chamber in fluid communication with the first upstream energy turbine, and with the first downstream turbine; the second energy turbine being in fluid communication with the first upstream turbine, and with a heat exchanger of the downstream recuperator.

[0020]

[0012] The invention makes it possible to propose a turbogenerator operating according to the IRReGT cycle, with a single electrical machine coupled to two expansion turbines. These expansion turbines make it possible to recover the excess power generated by each turbocharger (compressor and turbine assembly).

[0021]

[0013] Furthermore, the architecture including a high pressure stage and a low pressure stage, as well as the cooler and the combustion chambers, makes it possible to significantly increase the energy efficiency of the system. In addition, the use of one generator instead of two reduces the complexity of mounting the power electronics.

[0022]

[0014] According to a variant, the turbomachine further comprises a third energy turbine on the third axis, and the turbogenerator system further comprises:

[0023] - a second cooler in fluid communication with the first compressor downstream;

[0024] - a third combustion chamber in fluid communication with the second upstream energy turbine in place of the heat exchanger of the recuperator;

[0025] - at least a third turbocharger which comprises, on a fourth axis, a third compressor in fluid communication with the second downstream cooler; and a third turbine in fluid communication with the third upstream combustion chamber, and with the third downstream energy turbine, the third energy turbine being in fluid communication with the heat exchanger of the downstream recuperator.

[0026]

[0015] This makes it possible to further improve the energy efficiency of the system by adding a pressure stage with an additional turbocharger and an additional energy turbine.

[0016] According to a variant, the first turbocharger is dimensioned so that the power of the first turbine is equal to the power of the first compressor. This makes it possible to generate excess power at the first turbocharger.

[0027]

[0017] According to a variant, the second turbocharger is sized so that the power of the second turbine is equal to the power of the second compressor. This makes it possible to generate excess power at the second turbocharger.

[0028]

[0018] According to one variant, the turbogenerator system comprises at least one heating circuit connected to a heat exchanger of at least one cooler.

[0029]

[0019] This makes it possible to use the turbogenerator system to provide heating, for example, of the vehicle interior.

[0030]

[0020] According to one variant, the heating circuit comprises a heating device and a circulation pump.

[0031]

[0021] According to one variant, the fluid circuit comprises an air filter at the start of the circuit.

[0032]

[0022] This helps to limit impurities in the air of the turbogenerator system.

[0033]

[0023] The invention further relates to a method of manufacturing a turbogenerator system for a motor vehicle according to the invention, the method comprising the following steps:

[0034] - put the cooler in fluid communication with the first compressor upstream, and with the second compressor downstream;

[0035] - put the recuperator in fluid communication with the second upstream compressor;

[0036] - place the first combustion chamber in fluid communication with the upstream recuperator, and with the second downstream turbine;

[0037] - put the first energy turbine in fluid communication with the second upstream turbine;

[0038] - placing the second combustion chamber in fluid communication with the first energy turbine upstream, and with the first turbine downstream;

[0039] - place the second energy turbine in fluid communication with the first turbine upstream, and with a heat exchanger of the recuperator downstream.

[0040]

[0024] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which:

[0041] - [Fig.1] schematically illustrates an IRReGT type turbogenerator system architecture according to the prior art;

[0042] - [Fig.2] schematically illustrates an IRReGT type turbogenerator system architecture according to a first embodiment, with two turbochargers;

[0043] - [Fig.3] schematically illustrates a variant of the embodiment of Figure 2 with a heating device; and

[0044] - [Fig.4] schematically illustrates an architecture of an IRReGT type turbogenerator system according to a second embodiment, with three turbochargers.

[0045]

[0025] Although the IRReGT (Intercooled Recuperative Reheat Gas Turbine) cycle has advantages, its physical implementation poses certain problems.

[0046]

[0026] One can imagine putting the entire system on a single axis with a single electric machine as in the prior art illustrated in figure 1. However, several technical problems arise in this configuration:

[0047] - The shaft that connects the first compressor to the last turbine becomes long and this causes vibration problems at high speed;

[0048] - The turbogenerator system becomes bulky, and we will be constrained by the length of the system;

[0049] - It is necessary to ensure a high pressure seal at the inlet of compressor C2 (the flow being compressed to 3 bars);

[0050] - It is necessary to ensure a high pressure and high temperature seal at the outlet of the T1 turbine;

[0051] - It is necessary to ensure a high pressure and high temperature seal at the inlet of the T2 turbine.

[0052]

[0027] All these technical problems have pushed the applicant to decouple the two turbomachines and have two e-turbomachines (compressor, electric machine, and turbine assembly). This architecture comprises: - a low-pressure e-turbomachine (first turbocharger) on a first axis A1, formed by a compressor C1, an electric machine and a turbine T1; and

[0053] - a high-pressure e-turbomachine (second turbocharger) on a second axis A2, formed by a compressor C2, an electric machine and a turbine T2.

[0054]

[0028] The problem with the IRReGT cycle in this case is that it requires two electrical machines and therefore two inverters and two power electronics boards, which increases the complexity of the power electronics.

[0055]

[0029] To overcome the problem presented above, the invention proposes an IRReGT cycle which can comprise a single electric machine while keeping separate turbochargers. The corresponding system is illustrated in Figure 2.

[0056]

[0030] To do this, we will use the two turbochargers without an electric machine. The first turbocharger (low pressure) is sized so that the power of turbine T1 is equal to the power of compressor C1.

[0057]

[0031] The excess power (remaining unrecovered) will be recovered on a so-called energy turbine Te2 on an axis A3.

[0058]

[0032] Similarly, we will propose a high pressure turbocharger formed by the compressor C2, the turbine T2 on an axis A2. The power of the turbine T2 is equal to the power of the compressor C2. The excess power will be recovered by the energy turbine Tel on the axis A3.

[0059]

[0033] We will therefore have a third turbomotor formed by the electric machine EM, and the two energy turbines Tel and Te2.

[0060]

[0034] By doing so, it is possible to propose a cycle with a single electrical machine, a single power electronics and a single inverter.

[0061]

[0035] More specifically, the system comprises:

[0062] - a first turbocharger comprising a compressor C1 and a turbine T1 on an axis A1;

[0063] - a second turbocharger comprising a compressor C2 and a turbine T2 on an axis A2; - a cooler I in fluid communication with the compressor C2 upstream, and with the compressor C2 downstream;

[0064] - a recuperator R in fluid communication with the compressor C2 upstream;

[0065] - a combustion chamber CC1 in fluid communication with the recuperator R upstream, and with the turbine T2 downstream;

[0066] - a turbomachine comprising so-called energy turbines Tel, Te2, and an electric generator EM on an axis A3, the energy turbine Tel being in fluid communication with the upstream turbine T2;

[0067] - a combustion chamber CC2 in fluid communication with the energy turbine Tel upstream, and with the turbine T1 downstream; the energy turbine Te2 being in fluid communication with the turbine T1 upstream, and with a heat exchanger HE of the recuperator R downstream.

[0068]

[0036] Compared to the prior art US2022 / 0152754 A1, this does not recover power at the output of the high pressure stage. Thermodynamically, the system will not operate at the maximum efficiency point or the maximum specific net work point, because there is no work generated on the high pressure stage.

[0069]

[0037] The technical advantages are as follows:

[0070] - Simplification of the system in the preferred variant (one machine, one inverter, one power electronics);

[0071] - The power production part can be positioned at different locations within the functional volume of the system.

[0072]

[0038] In a variant illustrated in figure 3, a heating circuit can be added with a heating device H.

[0073]

[0039] In another variant illustrated in figure 4, we can also propose a triple-stage machine with the same principle, with in addition:

[0074] - another Te3 energy turbine on axis A3;

[0075] - another cooler I2 in fluid communication with the first compressor C1 downstream;

[0076] - another combustion chamber CC3 in fluid communication with the other energy turbine Te3 upstream in place of the heat exchanger HE of the recuperator R; - at least a third turbocharger which comprises, on another axis A4, another compressor C3 in fluid communication with the other cooler 12 downstream; and another turbine T3 in fluid communication with the other combustion chamber CC3 upstream, and with the other energy turbine Te3 downstream, the other energy turbine Te3 being in fluid communication with the heat exchanger HE of the recuperator R downstream.

[0077]

[0040] Furthermore, the same concept can be used but with different types of turbomachines or compression and expansion machines.

[0041] The idea remains valid for scroll, gear, screw compressor / turbine technologies; radial, axial, or piston turbomachines.

[0078]

[0042] Using a single electric machine allows for a reduction in positive environmental impact (less use of resources / materials).

Claims

CLAIMS 1. Motor vehicle comprising a turbogenerator system having a fluid circuit from an upstream to a downstream, the turbogenerator system comprising: - a first turbocharger comprising a first compressor (C1) and a first turbine (T1) on a first axis (A1); - a second turbocharger comprising a second compressor (C2) and a second turbine (T2) on a second axis (A2); - a cooler (I) in fluid communication with the first compressor (C1) upstream, and with the second compressor (C2) downstream; - a recuperator (R) in fluid communication with the second compressor (C2) upstream; - a first combustion chamber (CC1) in fluid communication with the recuperator (R) upstream, and with the second turbine (T2) downstream; - a turbomachine comprising a first and a second energy turbine (Tel, Te2), and an electric generator (EM) on a third axis (A3), the first energy turbine (Tel) being in fluid communication with the second turbine (T2) upstream; - a second combustion chamber (CC2) in fluid communication with the first energy turbine (Tel) upstream, and with the first turbine (T1) downstream; the second energy turbine (Te2) being in fluid communication with the first turbine (T1) upstream, and with a heat exchanger (HE) of the recuperator (R) downstream.

2. Motor vehicle according to claim 1, characterized in that the turbomachine further comprises a third energy turbine (Te3) on the third axis (A3), and in that the turbogenerator system further comprises: - a second cooler (I2) in fluid communication with the first compressor (C1) downstream; - a third combustion chamber (CC3) in fluid communication with the second energy turbine (Te3) upstream in place of the exchanger heat (HE) from the recuperator (R); - at least a third turbocharger which comprises, on a fourth axis (A4), a third compressor (C3) in fluid communication with the second cooler (I2) downstream; and a third turbine (T3) in fluid communication with the third combustion chamber (CC3) upstream, and with the third energy turbine (Te3) downstream, the third energy turbine (Te3) being in fluid communication with the heat exchanger (HE) of the recuperator (R) downstream.

3. Motor vehicle according to any one of claims 1 to 2, characterized in that the first turbocharger is sized so that the power of the first turbine (T1) is equal to the power of the first compressor (C1).

4. Motor vehicle according to any one of claims 1 to 3, characterized in that the second turbocharger is sized so that the power of the second turbine (T2) is equal to the power of the second compressor (C2).

5. Motor vehicle according to any one of claims 1 to 4, characterized in that the turbogenerator system comprises at least one heating circuit connected to a heat exchanger (HE) of at least one cooler (I).

6. Motor vehicle according to claim 5, characterized in that the heating circuit comprises a heating device (H) and a circulation pump (P).

7. Motor vehicle according to any one of claims 1 to 6, characterized in that the fluid circuit comprises an air filter (AF) at the start of the circuit.

8. A method of manufacturing a turbogenerator system for a motor vehicle according to any one of claims 1 to 7, the method comprising the following steps: - putting the cooler (I) in fluid communication with the first compressor (C1) upstream, and with the second compressor (C2) downstream; - put the recuperator (R) in fluid communication with the second compressor (C2) upstream; - place the first combustion chamber (CC1) in fluid communication with the recuperator (R) upstream, and with the second turbine (T2) downstream; - putting the first energy turbine (Tel) in fluid communication with the second turbine (T2) upstream; - putting the second combustion chamber (CC2) in fluid communication with the first energy turbine (Tel) upstream, and with the first turbine (T1) downstream; - place the second energy turbine (Te2) in fluid communication with the first turbine (T1) upstream, and with a heat exchanger (HE) of the recuperator (R) downstream.

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