MOTORIZED TURBOVERCOMPRESSOR OF AN AIR CONDITIONING SYSTEM WITH OPTIMAL COOLING

Description

Technical field of the invention

[0001] The invention relates to a motorized turbocharger, forming part of an air conditioning system. In particular, the invention relates to a motorized turbocharger with optimized cooling, which can for example be used in a vehicle comprising an air conditioning system, for example of the aeronautical, railway, or maritime type. Technological background

[0002] Engine-driven turbochargers are used in several contexts, including in vehicles, for example in an air conditioning system.

[0003] These engine-driven turbochargers typically include an engine-driven compressor that compresses outside air. A major issue with these turbochargers is cooling the engine of the engine-driven turbocharger.

[0004] On the one hand, in an air conditioning system, the main problem is to ensure this cooling without too much impact on the performance and costs of the air conditioning system, in particular by limiting the use of cold air intake from outside and / or by not causing an additional demand for pressurized air which would lead to a greater need for reheating, which is counterproductive.

[0005] In particular, engine cooling must be sufficiently efficient to allow an engine power density compatible in terms of mass and size with integration into an on-board system, in particular a vehicle, for example an aircraft.

[0006] In addition, the temperature levels to which the components of the powered turbocharger, and in particular the engine, are subjected, must be controlled in order to prevent any malfunction, and must be compatible with the reliability levels required in on-board systems, in particular the very high levels of reliability required in an aeronautical application.

[0007] The energy consumption generated by engine cooling must remain low so as not to negatively impact the overall efficiency of the system in which it is embedded. These energy efficiency and effectiveness considerations make it possible, in particular, to control the overall efficiency of the air conditioning system.

[0008] Finally, performance must also be studied at the global level, particularly in terms of mass and complexity, which must remain reasonable otherwise the overall performance of the vehicle will be penalized.

[0009] Solutions proposed in the prior art consist of cooling the engine by heat exchange with a liquid loop used as a heat sink. In particular, in some systems, especially in the automotive field, a liquid loop is already used to cool other components and is led to the engine for cooling. However, this solution is complex to implement in the absence of a pre-existing liquid loop, and adds complexity and a decrease in performance in an existing liquid loop due to the additional component to be cooled.

[0010] Another solution for cooling the compressor motor is to ventilate with air taken from outside the vehicle.

[0011] In this case, the ventilation flow is generally zero when the vehicle is stopped (especially on the ground for an aircraft). Fans are used to compensate for this lack of ventilation, which adds complexity to the system and reduces energy performance. More generally, the extraction of ventilation air leads to a drop in vehicle performance.

[0012] The inventors sought to propose a new type of motorized turbocharger for an air conditioning system, allowing good cooling of the engine.

[0013] The state of the art is illustrated by document EP-A1-3 385 170. Objectives of the invention

[0014] The invention aims to provide a motorized turbocharger for an air conditioning system making it possible to overcome at least one of the drawbacks of the motorized turbochargers of the prior art.

[0015] The invention aims in particular to provide, in at least one embodiment, an energy-efficient motorized turbocharger for an air conditioning system.

[0016] The invention aims in particular to provide, in at least one embodiment, a motorized turbocharger usable whatever the state of the vehicle and the external conditions.

[0017] The invention aims in particular to provide, in at least one embodiment, a compact and lightweight motorized turbocharger. Statement of the invention

[0018] To this end, the invention relates to a motorized turbocharger according to claim 1.

[0019] A powered turbocharger according to the invention therefore provides efficient and energy-saving engine cooling, taking full advantage of the air leaving the cabin. A cabin is understood to mean the part of the vehicle accommodating the elements transported by the vehicle, in particular the vehicle's passengers. It is also referred to as the passenger compartment.

[0020] When used in an air conditioning system, the main function of the turbocharger compressor is to allow the air from the air intake duct to reach or approach the required pressure in the cabin.

[0021] An air treatment device of the air conditioning system may be arranged between the powered turbocharger and the cabin to perform additional treatments, upstream or downstream of the cabin. In particular, the air treatment device comprises any element complementary to the powered turbocharger to treat the air circulating in the air conditioning system between the compressor and the energy recovery turbine of the powered turbocharger, for example one or more additional compressors to achieve higher compression ratios, one or more heat exchangers, a water extraction loop for extracting water, one or more expansion turbines, etc.

[0022] The air leaving the cabin is first expanded in an energy recovery turbine to a pressure close to the vehicle's external pressure, which allows energy (expansion enthalpy) to be recovered that can be used in the system to improve overall energy efficiency. In addition, the expansion in the turbine has the effect of reducing the cabin air temperature, and condensing the water present in the cabin air to form suspended water droplets.

[0023] Thus, expanded air is particularly effective in serving as a cooling medium for the engine crankcase and the motor. For example, expanded air is injected into a cooling circuit on the outer surface of the crankcase. This expanded air, which is cooler than the engine, will cool the engine crankcase and the motor by thermal conduction, and the water suspended in the expanded air will vaporize in the presence of the heat released by the engine and the engine crankcase, absorbing this heat, so as to improve the cooling of the engine crankcase and the motor.

[0024] The use of expanded air therefore makes it possible to cool more efficiently than in the devices of the prior art, or to cool in the same way with a lower air flow rate, which improves the overall energy efficiency of the motorized turbocharger, the air conditioning system in which it is integrated, and the vehicle in which the air conditioning system is installed.

[0025] If the air conditioning system includes a water extraction loop, the cooling channel may include means for injecting water extracted by the water extraction loop, configured to re-inject the extracted water into the cooling channel to enhance cooling.

[0026] The motorized turbocharger does not depend on an external system for cooling its compressor motor.

[0027] Advantageously and according to the invention, the energy recovery turbine is arranged on the transmission shaft.

[0028] According to this aspect of the invention, the compressor, the turbine and the motor are connected by the drive shaft and thus form the motorized turbocharger as a single unit. The energy recovered by the turbine is thus used to reduce the energy consumption of the engine required to drive the compressor, thereby reducing the heat generated by the engine.

[0029] Advantageously and according to the invention, the motorized turbocharger comprises a bifurcation arranged between the outlet of the turbine and the cooling channel, the bifurcation comprising an inlet configured to receive the expanded air, and comprising at least two outlets, a first outlet configured to conduct a portion of the expanded air flow towards the cooling channel, and a second outlet configured to conduct another portion of the expanded air flow towards an exhaust outlet.

[0030] According to this aspect of the invention, the bifurcation allows the pressure at the turbine outlet to be balanced: if all of the expanded air is sent into the cooling channel to cool the engine casing and the engine, a resulting pressure drop may reduce the overall performance of the system, in particular the performance of the turbine.

[0031] By allowing passive flow balancing between the cooling channel and the outlet at the bifurcation, the turbine operates at its maximum performance (the ratio between the pressure at the turbine inlet and the turbine outlet is optimized) because the pressure drop downstream of its outlet is optimized, and the cooling of the cabin air is efficient, which improves the cooling of the engine and the engine casing.

[0032] Advantageously and according to the invention, the bifurcation is configured so that a majority of the water suspended in the conditioned air is conducted towards the cooling channel.

[0033] According to this aspect of the invention, the bifurcation optimizes the water distribution of the cabin air sent to the cooling channel and the cabin air directly evacuated. The presence of water suspended in the cabin air does not impact the pressure drop performance but is advantageous for cooling. Thus, the bifurcation is configured so that the majority of the water is transmitted to the cooling channel. This configuration can be done actively (controlled) or preferably passively (without intervention, which notably limits the energy consumed and the complexity of the system).For example, the bifurcation has a geometric shape in which the first outlet connected to the cooling channel is substantially collinear with the direction of the conditioned air flow so that the water present in the flow is conducted mainly into this outlet, the second outlet being oriented at a different angle so that the water preferentially heads towards the first outlet.

[0034] Advantageously and according to the invention, the motor casing comprises cooling fins.

[0035] According to this aspect of the invention, the fins allow for maximizing cooling of the engine and the housing. The fins are made of a heat-conducting material to maximize heat exchange.

[0036] According to other variants of the invention, any other device improving heat exchange can be added to the engine casing.

[0037] The invention also relates to a method for supplying a cabin of a vehicle, characterized in that it comprises the following steps: compress, via a compressor driven by an engine, air coming from an air inlet duct and conduct this pressurized air, at a pressure corresponding to the pressure necessary to supply the cabin, towards an inlet of the cabin, expand, via an energy recovery turbine, cabin air coming from an outlet of the cabin, conduct at least part of the air expanded by the turbine, towards a casing of the compressor motor so as to cool said motor casing and said motor.

[0038] Advantageously, the supply method according to the invention is implemented by a motorized turbocharger according to the invention.

[0039] Advantageously, the motorized turbocharger according to the invention implements the supply method according to the invention.

[0040] The invention also relates to an air conditioning system, configured to supply conditioned air to a cabin of a vehicle, characterized in that it comprises a motorized turbocharger according to the invention configured to supply said cabin of the vehicle with pressurized air.

[0041] Advantageously and according to the invention, the air conditioning system comprises an air treatment device, configured to receive the pressurized air downstream of the cabin inlet and / or to receive the cabin air downstream of the energy recovery turbine, and comprising equipment intended to treat the pressurized air before the cabin inlet and / or to treat the air coming from the cabin outlet.

[0042] Advantageously and according to the invention, the air treatment device comprises one or more pieces of equipment from the following list: one or more additional compressors, one or more heat exchangers, a water extraction loop to extract water, one or more expansion turbines.

[0043] The air treatment device thus brings together all the equipment necessary for the air conditioning system in addition to the motorized turbocharger to obtain conditioned air to be supplied to the cabin and / or to treat the air leaving the cabin.

[0044] The invention also relates to a vehicle comprising an air conditioning system and a cabin, characterized in that it comprises a motorized turbocharger according to the invention configured to supply the cabin with pressurized air.

[0045] The vehicle is, for example, a motor, aircraft, maritime or railway vehicle.

[0046] The invention also relates to a motorized turbocharger, a powering method, an air conditioning system and a vehicle, characterized in combination by all or part of the features mentioned above or below. List of figures

[0047] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which: [ Fig. 1 ] is a schematic view of a motorized turbocharger of an air conditioning system according to one embodiment of the invention. Detailed description of an embodiment of the invention

[0048] In the figures, scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0049] Furthermore, identical, similar or analogous elements are designated by the same references in all figures.

[0050] There Figure 1 schematically illustrates a motorized turbocharger 10 forming part of an air conditioning system 100, arranged in particular to compress the air entering the air conditioning system to the pressure necessary to supply a cabin of the vehicle, and to expand the air leaving the cabin to recover its energy in the form of enthalpy and improve the energy efficiency of the system.

[0051] The air conditioning system is configured to provide conditioned air, for example to a vehicle in which it is mounted, in particular in the cabin or passenger compartment of this vehicle (cabin of an aircraft or a boat, car or wagon of a railway vehicle, passenger compartment of a motor vehicle, etc.). For generalization, the term "cabin" is used in the remainder of the description to name the cabin or passenger compartment of a vehicle, depending on the type of vehicle in which the invention is implemented.

[0052] The cabin 110 comprises a cabin inlet 112 and a cabin outlet 114 from which air exits having passed through the cabin, called cabin air 24.

[0053] The cabin 110 is supplied with pressurized air, in particular by a compressor 12 supplied with air by an air intake duct 14. The air coming from the air intake duct 14 is, for example, outside air, or air coming from another system on board the vehicle which includes the air conditioning system. For example, in an aircraft, the air may be taken from a propulsion engine.

[0054] The compressor 12 is driven in rotation by a motor 16 surrounded by a casing 18. The motor drives in rotation a transmission shaft 19 to which the compressor 12 is connected.

[0055] The air conditioning system generally comprises additional air treatment equipment, combined here in an air treatment device 120. Thus, the air treatment device 120 designates all of the other equipment constituting the air conditioning system in addition to the motorized turbocharger 10, for example one or more compressors, one or more turbines, one or more heat exchangers, a water extraction loop, etc.

[0056] The pressurized air, possibly treated by the air treatment device 120, enters through the inlet 112 of the cabin and then passes through the cabin 110.

[0057] The cabin air 24 is optionally treated at its outlet by the air treatment device. The cabin air 24 is then expanded by an energy recovery turbine 26 of the motorized turbocharger 10. The energy recovery turbine 26 makes it possible to recover energy from the cabin air 24, by expanding and cooling this cabin air 24. In this embodiment, the energy recovery turbine 26 is connected to the transmission shaft 19 in order to reduce the energy consumption of the engine 16 to drive the compressor 12. The turbine 26, the engine 16 and the compressor 12 together form the motorized turbocharger 10.

[0058] In the prior art, the air exiting the energy recovery turbine is sent outside after energy recovery.

[0059] In the motorized turbocharger of the invention, the air leaving the turbine, called expanded air, is also used as a cooling source.

[0060] In particular, as shown in this embodiment, the expanded air 28 leaves the turbine 26 and reaches a bifurcation 30. This bifurcation comprises an inlet connected to the outlet of the turbine 26 and makes it possible to conduct a portion of the expanded air 28 towards a first outlet towards a cooling channel 32, and the other portion of the expanded air 28 either towards a first exhaust outlet 34a towards the atmosphere or towards a system or zone of the vehicle whose pressure is close to atmospheric pressure.

[0061] The portion of the expanded air 28 flowing through the cooling channel 32 is conducted to the engine casing 18 to cool the engine casing 18 and the engine 16. To facilitate cooling, the engine casing 18 may include fins (not shown) or any other device improving heat exchange. Any water droplets suspended in the expanded air 28 conducted to the engine casing 18 improve cooling by vaporizing these droplets under the effect of the heat generated by the engine 16 to drive the compressor 12. To maximize cooling, it is possible to inject water extracted by a water extraction loop of the water treatment device. After cooling the engine 16 and the engine casing 18, the air may be discharged through a second separate exhaust outlet 34b, or be redirected to the first exhaust outlet 34a.

[0062] The branch 30 allows passive control of the pressure drop at the cooling channel 32 and the engine casing 18: the pressure at the first exhaust outlet 34a or the second exhaust outlet 34b is the ambient pressure and the pressure at the branch 30 is the same for the portion of the expanded air 28 circulating in the branch of the cooling channel 32 and the portion of the expanded air 28 circulating in the branch leading to the first exhaust outlet 34a of the vehicle, which makes it possible to balance the flow rates between the two branches.

[0063] The air conditioning system incorporating the motorized turbocharger can be integrated into a motor, railway, marine or aeronautical vehicle.

Claims

1. A driven turbocompressor of an air conditioning system for supplying conditioned air to a cabin of a vehicle, the driven turbocompressor comprising: - an air intake duct (14) configured to collect ambient air at ambient pressure, - a compressor (12) connected to the air intake duct (14) and configured to be connected to an inlet (112) of the cabin (110), configured to receive air originating from the air intake duct (14), to compress the air originating from the air intake duct (14) and to supply pressurized air at a pressure corresponding to the pressure needed to supply the cabin (110), - a motor (16) connected to the compressor (12) by a transmission shaft (19), configured to drive the compressor (12) and surrounded by a casing (18), - an energy recovery turbine (26) configured to be connected to an outlet (114) of the cabin (110), and configured to expand the cabin air (24) originating from the outlet (114) of the cabin (110) to supply expanded air (28) via an outlet of the turbine (26), characterized in that it comprises a cooling duct (32) connecting the outlet of the turbine (26) and the casing (18) of the motor, said cooling duct (32) being configured to receive at least some of the expanded air (28), so as to cool the motor casing (18) and the motor (16).

2. The driven turbocompressor according to claim 1, characterized in that the energy recovery turbine (26) is arranged on the transmission shaft (19).

3. The driven turbocompressor according to one of claims 1 or 2, characterized in that it comprises a bifurcation (30) arranged between the outlet of the turbine (26) and the cooling duct (32), the bifurcation comprising an inlet configured to receive the expanded air (28), and comprising at least two outlets, a first outlet configured to direct some of the flow of expanded air to the cooling duct (32), and a second outlet configured to direct another portion of the flow of expanded air to an exhaust outlet (34a).

4. The driven turbocompressor according to claim 3, characterized in that the bifurcation (30) is configured so that a majority of the water in the expanded air (28) is directed to the cooling duct (32).

5. The driven turbocompressor according to one of claims 1 to 4, characterized in that the casing (18) of the motor comprises cooling fins.

6. A method for supplying pressurized air to a cabin of a vehicle, characterized in that it comprises the following steps: - compressing, via a compressor (12) driven by a motor (16), air originating from an air intake duct (14), and directing that pressurized air (20), at a pressure corresponding to the pressure needed to supply the cabin, to an inlet (112) of the cabin (110), - expanding, via an energy recovery turbine (26), cabin air (24) originating from an outlet (114) of the cabin, - directing at least some of the air expanded by the turbine to a casing (18) of the compressor (12) motor so as to cool said motor casing (18) and said motor (16).

7. An air conditioning system, configured to supply conditioned air to a cabin of a vehicle, characterized in that it comprises a driven turbocompressor (10) according to one of claims 1 to 5 configured to supply said cabin of the vehicle with pressurized air.

8. The air conditioning system according to claim 7, characterized in that it comprises an air treatment device (120), configured to receive the pressurized air downstream of the inlet of the cabin and / or to receive the cabin air downstream of the energy recovery turbine, and comprising equipments intended to treat the pressurized air before the inlet of the cabin and / or to treat the air coming from the outlet of the cabin.

9. The air conditioning system according to claim 8, characterized in that the air treatment device comprises one or more equipments from the following list: - one or more additional compressors, - one or more heat exchangers, - a water extraction loop for extracting water, - one or more expansion turbines.

10. A vehicle comprising an air conditioning system and a cabin, characterized in that it comprises a driven turbocompressor (10) according to one of claims 1 to 5 configured to supply the cabin with pressurized air.