Compressor for vehicles with enhanced oil separation efficiency

Abstract

Rotary compressor (100), for an air treatment system of a vehicle, comprising a compression cell (2) for producing compressed gas streams, and a separation unit (200) for separating oil from the compressed gas streams, wherein the separation unit is in fluid communication with the compression cell and is configured to separate oil from the compressed gas stream exiting an outlet (9) of the compression cell, and wherein the separation unit comprises a first separator (204), in particular a centrifugal separator, and a second separator (202), in particular a deceleration separator, wherein the second separator is positioned downstream of the first separator in the direction of the compressed gas stream.

Description

[0001] The present invention relates to a compressor, in particular an electric compressor, for connection with an air treatment system of electrically powered commercial vehicles, hybrid vehicles vehicle and / or rail vehicles. Specifically, the present invention relates to an electric compressor including an integrated oil separation unit for enhancing oil separation efficiency.

[0002] Rotary compressors, such as rotary vane compressors and screw compressors, a type of positive displacement compressors, are widely used in various industrial and automotive applications due to their ability to deliver consistent air pressure and flow rates. These compressors typically rely on oil lubrication to maintain efficient operation and longevity. Unlike other compressor types, rotary compressors do not require an oil pump to circulate the lubricant. Instead, they utilize the pressure differentials generated within the compressor housing to keep the oil moving throughout the system.

[0003] In a rotary compressor, oil separation presents a significant challenge due to the nature of the compressor's design and operation. The compressor relies on oil for lubrication, cooling, and sealing purposes. During operation, oil is pressurized within the system and is often mixed with the compressed gas. This mixture of oil and gas can lead to issues such as reduced efficiency, increased wear on components, and potential contamination of the downstream equipment or processes.

[0004] As the compressor operates, the oil is drawn from an oil sump and circulated through various components, for example, bearings and / or vanes. However, the high-speed rotation of the vanes and the turbulent flow within the compressor housing can cause the oil to become entrained in the compressed gas stream. Effective separation of the oil from the gas is crucial to ensure that only minimal amounts of oil are carried over with the compressed air. Failure to adequately separate the oil can result in excessive oil consumption, reduced lubrication efficiency, and potential damage to the compressor and connected systems.

[0005] Achieving efficient oil separation in a rotary compressor, such as a rotary vane compressor, requires specialized filtration systems that effectively remove oil from the compressed gas before it exits the compressor. The design and effectiveness of these separation systems are crucial for maintaining the reliability and longevity of the compressor, as well as ensuring the purity and quality of the compressed air output.

[0006] Designing an effective filtration system is complex due to the varying operational conditions-such as pressure, temperature, air-oil mass flow, and oil particle size-all of which impact separation efficiency. High-efficiency separation typically demands a multi-stage filtration process or a sufficiently large oil sump housing to calm and stabilize the air-oil mixture before filtration.

[0007] For instance, multi-stage separation systems are commonly used in the industry, with multiple filter stages often arranged serially or in parallel within a single housing to reduce costs. However, in vehicle applications where compressors frequently cycle on and off, maintaining sufficient efficiency remains challenging, especially when the oil sump housing is undersized.

[0008] It is an object of the present invention to address the problem of efficient oil separation while maintaining cost-effectiveness.

[0009] This object is achieved in the present invention by a rotary compressor according to claim 1. Preferred embodiments are addressed by the dependent claims respectively.

[0010] According to the present invention, a rotary compressor for an air treatment system of a vehicle, in particular electric vehicles, hybrid vehicles and / or commercial vehicles, hybrid vehicles vehicle and / or rail vehicles, is provided. The rotary compressor comprises a compression cell for producing compressed gas streams, and a separation unit for separating oil from the compressed gas streams, in particular the gas stream directly exiting an outlet of the compression cell, wherein the separation unit is in fluid communication with the compression cell and is configured to separate oil from the compressed gas stream exiting an outlet of the compression cell, and wherein the separation unit comprises a first separator, in particular a centrifugal separator, and a second separator, in particular a flow deceleration separator, wherein the second separator is positioned downstream of the first separation in the direction of the compressed gas stream.

[0011] The present invention is based on the basic idea to leverage the mass inertia of the oil droplets and aerosol, as well as the tendency of smaller droplets to combine into larger particles. By utilizing these properties, the present invention aims to enhance the efficiency of oil separation from the compressed gas stream within the compressor. The integration of a separation unit within a limited installation space is particularly advantageous for electrically powered commercial vehicles, including hybrid vehicles. This compact design allows for effective oil separation without compromising the available space for other critical components, making it ideal for modern vehicle architectures where space is constrained.

[0012] Advantageously, the present invention enables more effective separation and improves the overall performance and longevity of the compressor. Specifically, the compressor comprises an oil separation unit, preferably comprising a centrifugal separator or a vortex separator and a knitted mesh filter, housed within a compressor housing for separating oil particles from compressed gas streams discharging from a compression cell. The separation unit is in fluid communication with a further filter disposes downstream from the separation unit in the direction of the compressed gas stream.

[0013] In particular, it is envisaged to introduce a two-stage separation unit in the path of the compressed gas stream exiting through an outlet of the compression cell (the discharge opening). The separation unit is configured to cause the oil droplets and aerosols to adhere to it and coalesce into larger droplets due to continuous accumulation via the gas stream. The larger oil droplets or particles, therefore, are configured to be separated out and are collected in an oil sump before they can enter a filter (e.g. a cartridge filter, a coalescing filter).

[0014] Advantageously, the separation unit's two-stage process enhances oil removal efficiency from the compressed gas stream. The first stage uses centrifugal forces to separate larger oil particles, while the second stage reduces the speed of the flow of the compressed gas stream to capture finer particles. This multi-stage approach ensures thorough separation, reducing the risk of oil contamination and improving the overall purity of the compressed gas. The combination of centrifugal and filtration methods also extends the life of the equipment by preventing oil build-up and ensuring optimal performance.

[0015] In particular, the centrifugal separator (the first separator) is configured to separate oil particles from the compressed gas stream by utilizing centrifugal force generated through swirling or spinning motion. Unlike systems that rely on a stationary medium to capture particles as the fluid passes through, centrifugal separators use dynamic motion to achieve separation.

[0016] In particular, the second stage of the oil separation process, oil separation occurs by reducing the speed of the flow of the compressed gas stream within the second separator, allowing oil droplets to coalesce and accumulate in the flow-slowing passage openings. As the flow velocity decreases, the inertial forces acting on the droplets diminish, enabling them to settle under the influence of gravity. This process enhances the efficiency of oil separation, ensuring that the majority of the oil is removed from the air stream before it exits the compressor.

[0017] In particular, the rotary compressor further comprises a filter for removing (or separating) oil particles, aerosols, liquid droplets, and fine particles from the compressed gas stream, wherein the filter is positioned downstream of the separation unit in the direction of the compressed gas stream.

[0018] In particular, the rotary compressor is configured to provide three distinct separation steps using an oil separation unit, including the first and second separators, and a third separator provided by a filter prior the compressed gas stream exits the compressor. In this way an effective and enhanced separation of oil particle from the air-oil mixture is achieved.

[0019] In particular, it is further envisaged that fluctuating oil levels in the compressed air are equalized by the second separator functioning as an oil accumulation device, so that the separation unit consistently receives air with a relatively constant oil content.

[0020] In particular, the second separator is configured to separate and collect accumulated oil particles. For example, the second separator comprises a vane separator, a mesh separator a sieve separator or the like.

[0021] In particular, the rotary compressor comprises an internal outlet opening configured to direct the compressed gas stream from the compression cell to the separation unit, e.g. to a first separator.

[0022] In particular, the separation unit is the first element that is configured to separate oil from the compressed gas stream.

[0023] In particular, the separation unit, e.g. the second separator, is in fluid communication with the filter using a connecting channel.

[0024] In particular, the separation unit, e.g. the first separator and the second separator, is configured to direct the oil, once separated from the compressed gas stream, into an oil sump of the rotary compressor.

[0025] In particular, the compressed gas streams comprise an air-oil mixture.

[0026] In particular, the oil sump and the compression cell are disposed within a main compressor housing.

[0027] In particular, the separation unit comprises a first end, a second end, and a body extending between the first and second ends, the compressed gas stream being configured to flow from the first end towards the second end.

[0028] In particular, the first separator is configured to be disposed at an outer periphery of a body of the separation unit.

[0029] In particular, the second separator is formed within a body of the separation unit near to a second end thereof.

[0030] In particular, the body of the separation unit comprises the second separator and an internal hollow chamber, wherein the second separator is disposed downstream of the hollow chamber in the direction of the compressed gas stream.

[0031] By optimizing the gas flow dynamics, the second separator enhances overall oil removal efficiency, ensuring a cleaner output.

[0032] In particular, the second separator comprises a deceleration chamber configured to reduce the velocity of the compressed gas stream, thereby allowing removal of oil droplets that may not have been captured in the first stage of the separation..

[0033] The second separator comprises a deceleration chamber and a transition chamber.

[0034] The transition chamber and the deceleration chamber are formed within the body of the separation unit.

[0035] The deceleration chamber comprises a base plate and a plurality of openings that are formed in the base plate. The openings define flow-reducing passages and are configured for collecting the oil droplets as they condense and fall under the influence of gravity into an oil sump. Advantageously, the design ensures that the collected oil can be easily drained or extracted

[0036] In particular, the deceleration chamber comprises a plurality of openings for communicating with the hollow chamber.

[0037] In particular, the transition chamber is disposed within the body of the separation unit near to the second end.

[0038] Alternatively, the filter chamber defines a cavity (is empty), e.g., with a specific geometry, to direct the compressed gas stream for collecting oil in a collection chamber.

[0039] In particular, the hollow chamber is disposed within the body of the separation unit near to the first end.

[0040] In particular, after separation using the first separator, the compressed gas stream is configured to flow into the hollow chamber within the body of the separation unit. Thereafter, the compressed gas stream is configured to flow through the plurality of openings of the deceleration chamber in the second separator for further separation by changing flow dynamics (reducing the flow seed of the compressed gas stream) . The oil separated by the second separator is then configured to be drip back into an oil sump or to be returned into a lubrication at any point of lower pressure.

[0041] In particular, the first separator is configured to separate oil particles (droplets) from the compressed gas stream by utilizing centrifugal forces generated through swirling motion.

[0042] In particular, the first separator comprises a projecting element, in particular a helical element, and a grooved channel, in particular helical channel, both of which are disposed around the outer periphery of the body of the separation.

[0043] In particular, the projecting element is configured to guide the compressed gas stream along the grooved channel, thereby generating the centrifugal force for accumulating the oil particles in the grooved channel 207.

[0044] In particular, the oil particles accumulated in the grooved channel are configured to drain to an oil sump of the rotary compressor by gravity once they coalesce to a mass that allows them to detach from the grooved channel.

[0045] In particular, a separation unit for a rotary compressor of an air treatment system of a vehicle, in particular an electric vehicle and / or a hybrid vehicle is provided. The separation unit comprises a first separator and a second separator for separating oil particles from a compressed gas stream in a two stages, wherein the second separator is downstream of the first separator in the direction of the compressed gas stream, wherein the first separator comprises a centrifugal separator and is configured to separate oil using centrifugal forces in a first stage, and wherein the second separator comprises a flow deceleration separator for further separating or capturing oil particles from the compressed gas stream in a second stage.

[0046] In particular, the separation unit is configured to be disposed between a compression cell and a filter (e.g. a coalescing filter) in the direction of the compressed gas stream.

[0047] Further details and advantages of the present invention are explained and described in more detail in the context of the embodiment as illustrated by the enclosed figures.

[0048] It is schematically shown: Fig. 1a schematic cross-sectional view of a rotary compressor for an air treatment system of a vehicle according to the prior art; Fig. 2a schematic cross-sectional view of a rotary compressor for an air treatment system of a vehicle according to the present invention; Fig. 3a schematic view of a separation unit according to the present invention; Fig. 4a schematic cross-sectional view of the separation unit according to the present invention; and Fig. 5a partial cross-sectional view of a rotary compressor according to the present invention.

[0049] Fig. 1 illustrates a schematic cross-sectional view of a rotary compressor, e.g. a rotary vane compressor, for an air treatment system of a vehicle according to the prior art. A rotary compressor comprises bearings 1 that support the rotating parts, a compression cell 2, e.g. a vane cell, where air compression occurs and a rotor 3 driving vanes 4. The vanes 4 slide within the rotor 3 to compress air, all housed within a compressor housing 5. A riser pipe 11 transfers oil from an oil sump 12 (within the compressor housing 5) to lubricate the bearings 1 and other moving parts.

[0050] A filter 8 is coupled to the compressor housing 5. The filter 8 is configured to filter out oil droplets and / or aerosols from the compressed gas stream (e.g. compressed air) before it exits the rotary compressor through an outflow channel 13 and enters an air treatment system. The compressor housing 5 further includes an intake channel 14 for drawing in a fluid to be compressed. The intake channel is in fluid communication with the compression cell.

[0051] The rotary compressor may further comprise a heat exchanger 10 that is coupled to the compressor housing 5 and is configured to cool the oil before it re-enters the compressor, ensuring efficient operation.

[0052] In a rotary compressor, the oil within the oil sump 12 is pressurized by the gas pressure within the compressor housing 5, drawn through a riser pipe 11, and directed into the bearings 1 of the compression cell 2. This oil then flows to the rotor 3 and the vanes 4, where it serves dual purposes - providing lubrication to reduce wear and ensuring effective sealing within the compressor chambers. As the compressor operates, the oil mixes with the compressed air, which is being conveyed through the compressor. This air-oil mixture also combines with oil that returns from the filter 8 through a first oil return channel 6 and with additional oil supplied through a second oil return channel 7 from the heat exchanger 10.

[0053] The air-oil mixture then flows through an outlet (a discharge opening) 9 of the compression cell 2, which defines a discharge cross-section, into the interior of the compressor housing 5. At this stage, the expansion of the discharge cross-section into the interior of the compressor housing 5 can induce turbulence, causing a fine aerosollike distribution of the oil particles within the air. This fine distribution makes it challenging to separate the oil from the compressed air. Almost most of the oil is filtered out by the filter 8 and returned to the oil circuit. However, the conveyed air may still contain larger, accumulated oil particles that need to be managed.

[0054] Fig. 2 shows a schematic cross-sectional view of a rotary compressor for an air treatment system of a vehicle according to the present invention.

[0055] The vehicle comprises an electrically powered commercial vehicle or a hybrid vehicle or a rail vehicle.

[0056] The rotary compressor 100 comprises all the components as outlined above with respect to Fig. 1. However, some of the components are not visible in Fig. 2.

[0057] The rotary compressor 100, for example, comprises a compressor housing 105 accommodating bearings 101, a compression cell 102, a rotor 103 and an oil sump 112. A riser pipe 111 for transferring oil from an oil sump 112 to lubricate the bearings 101 and other moving parts is not visible.

[0058] The rotary compressor 100 further comprises a separation unit 200 that is mounted in the compressor housing 105 downstream from the compression cell 102.

[0059] In particular, the separation unit 200 is the first element that is configured to separate oil from the compressed gas stream.

[0060] The outlet (not visible) of the compression cell 102 is connected via an air channel (not visible) with an internal outlet opening 125 within the compressor housing 105.

[0061] The internal outlet opening 125 is configured to direct the compressed gas stream from the compression cell to the separation unit 200, e.g. to a first separator 201.

[0062] The compressed gas stream is therefore configured to strike the first separator 201 disposed at an outer perimeter of the separation unit 200.

[0063] The rotary compressor 100 further comprises a filter 108 (e.g. a coalescing filter) for separating oil from the compressed gas stream.

[0064] The filter 108 is positioned downstream of the separation unit 200 in the direction of the compressed gas stream.

[0065] The separation unit 200 is in fluid communication with the filter 108 using a connecting channel 127.

[0066] The separation unit 200 comprises a first separator 201 and a second separator 202.

[0067] The separation unit 200 is configured to direct the oil droplets, once separated from the compressed gas stream, into the oil sump 112 of the rotary compressor 100.

[0068] The first separator 201 is configured to separate oil droplet from the compressed gas stream by utilizing centrifugal forces generated through swirling motion.

[0069] The first separator 201 comprises a projecting element 206, e.g. a helical element, and a grooved channel 207, e.g. a helical channel, both of which are disposed around the outer periphery of the body 205 of the separation unit 200.

[0070] The projecting element 206 is configured to guide the compressed gas stream along the grooved channel 207, thereby generating the centrifugal force for accumulating oil droplets in the grooved channel 207.

[0071] For example, the oil droplets accumulated in the grooved channel 207 are designed to drain into the oil sump 112 of the rotary compressor 100 by gravity. As the droplets merge and form a sufficiently large mass, they detach from the grooved channel 207. Once detached, the mass of oil droplets is directed by gravity to flow through a gap between the projecting element 206 and the compressor housing 105 into the oil sump 112, ensuring efficient removal and collection.

[0072] The design ensures that accumulated oil droplets are not entrained by the compressed gas flow and are able to efficiently gravitate downward into the oil sump 112. This gravity-driven drainage mechanism preserves the efficiency of the first separator by effectively removing oil from the compressed air and preventing excessive oil accumulation within the compressor. This, in turn, maintains optimal operational performance and reliability of the compressor system.

[0073] In particular, the design of the grooved channel includes a cylindrical section of the compressor housing (outer diameter of the channel) where oil droplets tend to accumulate. To facilitate the movement of the accumulated droplets under gravity, there is a gap between the helical element 206 and the cylindrical section of the compressor housing 105. This gap is optimized for the compressor's speed range; if it is too wide, air may bypass the helical element, preventing it from rotating and disrupting the separation process. If the gap is too narrow, oil droplets cannot pass through effectively. After leaving the second separator 202, the compressed gas stream is directed through the connecting channel 127 to the filter 108 and passes, for example, through several layers of filter fleece. In this process, even the smallest amounts of oil like aerosols are separated and routed to the collection return via an oil return collection chamber 129 and an oil return bore 128.

[0074] Fig. 3 illustrates a schematic view of the separation unit 200 according to the present invention.

[0075] The separation unit 200 comprises a first end 203, a second end 204 and a body 205 extending between the first end 203 and the second end 204.

[0076] For example, the compressed gas stream is configured to flow from the first end 203 towards the second end 204.

[0077] The first separator 201 is configured to be disposed at an outer periphery of the body 205.

[0078] The second separator 202 (see Fig. 4) is configured to be disposed inside the body 205 near to the second end 204.

[0079] In Fig. 4 a schematic cross-sectional view of the separation unit according to the present invention is shown.

[0080] A hollow chamber 208 is provided inside the body 205 upstream from the second separator 202 in the direction of the compressed gas stream.

[0081] The second separator 202, for example, comprises a flow deceleration separator and, is configured to reduce the velocity of the compressed gas stream. This reduction in speed enables a second stage of the oil separation.

[0082] The second separator 202 comprises a deceleration chamber 209 and a transition chamber 210.

[0083] The transition chamber 210 and the deceleration chamber 209 are both formed (integrated) within the body 205. The transition chamber 210, for example, has a cross-sectional area larger than or equal to that of the deceleration chamber 209.

[0084] The deceleration chamber 209 comprises a base plate 211 and a plurality of openings 212 (functioning as flow-accelerating passages) that are formed in the base plate 211. The plurality of openings 212 are configured to facilitate the collection of separated oil droplets.

[0085] In particular, in the grooved channel 207, the velocity of the compressed gas stream is lower than in the openings 212 due to the larger cross-sectional area of the grooved channel 207 compared to that of the openings 212. As a result, the flow accelerates when passing through the openings 212. Immediately after the openings 212, the flow speed decreases significantly within the deceleration chamber 209. Advantageously, this design causes the flow to first accelerate through the openings 212 and then slow down in the deceleration chamber 209. This ensures effective separation of oil from the gas stream.

[0086] The deceleration chamber 209 comprises a base plate 211 and a plurality of openings 212 (flow-reducing passages) that are formed in the base plate 211. The openings 212 are configured for collecting the separated oil droplets.

[0087] The oil droplets held back by the flow-slowing openings 212 and drips directly back into the oil sump 112 under gravity.

[0088] The hollow chamber 208 and the deceleration chamber 209 and the transition chamber 210 are in fluid communication through the plurality of openings 212 and configured to allow the passage of the compressed gas stream.

[0089] For example, the deceleration chamber 209 is disposed between the hollow chamber 208 at the first end 203 and the transition chamber 210 at the second end 204.

[0090] The transition chamber 210 is downstream of the deceleration chamber 209 in the direction of the compressed gas stream.

[0091] Alternatively, the second separator 202 comprises a filter chamber for separating oil, and a collection chamber for collecting the separated oil.

[0092] The filter chamber comprises, for example, vanes, e.g. angled vanes (not shown), or a specific geometry to direct the compressed gas stream and collect the oil in the collection chamber.

[0093] Alternatively, the filter chamber comprises, for example, a filter material (knitted filter material) for separating oil from the compressed gas stream and colleting it in the collection chamber.

[0094] In particular, the collection chamber, similar to the deceleration chamber, comprises a plurality of openings communicating with the hollow chamber.

[0095] In particular, after separation using the first separator 201, the compressed gas stream is configured to flow into the hollow chamber 208 within the body 205 of the separation unit 200.

[0096] Thereafter, the compressed gas stream is configured to flow into the second separator 202 through the plurality of openings 212 of the deceleration chamber 209 and into the transition chamber 210.

[0097] In the second separator 202, the openings 212 of the deceleration chamber 209 slow down the flow of the compressed gas stream, allowing oil droplets suspended in the gas stream to settle out and accumulate in the passages of the openings 212. As the gas stream passes from the deceleration chamber 209 into the transition chamber 210, the larger cross-sectional area of the transition chamber 210 further reduces the flow velocity. This additional drop in speed can help any remaining oil droplets to separate from the gas stream.

[0098] The present invention provides further for a separation unit 200 for a rotary compressor 100 of an air treatment system of a vehicle, in particular an electric vehicle and / or a hybrid vehicle and / or a rail vehicle, wherein the separation unit 200 comprises a first separator 201 and a second separator 202 for separating oil particles from a compressed gas stream in two stages as described above.

[0099] For example, the first separator 202 comprises a centrifugal separator and is configured to separate oil using centrifugal forces in a first stage, and the second separator 202 configured to separate and collect oil particles.

[0100] The separation unit 200 is configured to be disposed between a compression cell 102 and a filter 108 in the direction of the compressed gas stream.

[0101] In Fig. 5 a partial cross-sectional view of the compressor is shown.

[0102] The filter 108 comprises a discharge channel 130 which is in fluid communication with an outflow channel 130 for directing oil-free compressed gas stream through a discharge channel 130 (shown in Fig. 2) into an air treatment system.

[0103] The rotary compressor 100 further comprises the oil return collecting chamber 129 that is in fluid communication with the oil return bore 128 for returning the oil particles separated using the oil filter 108 into the compression cell 102 of the rotary compressor 100.REFERENCE SIGNS

[0104] 1Bearings 2Compression cell 3Rotor 4Vanes 5Compressor housing 6First oil return channel 7Second oil return channel 8Filter 9Outlet of the compression cell 10Heat exchanger 11Riser pipe 12Oil sump 13Outflow channel 14Intake channel 100Rotary compressor 101Bearings 102Compression cell 103Rotor 104Vanes 105Compressor housing 108Filter 110Heat exchanger 112Oil sump 113Outflow channel 125Internal outlet opening 127Connecting channel 128Oil return bore 129Oil return collecting chamber 130Discharge channel 200Separation unit 201First separator 202Second separator 203First end 204Second end 205Body 206Projecting element (helical projection) 207Grooved channel (helical channel) 208Hollow chamber 209Deceleration chamber 210Transition chamber 211Base plate 212Plurality of openings

Claims

1. A rotary compressor (100) for an air treatment system of a vehicle, in particular electric vehicles, hybrid vehicles and / or rail vehicles, comprising a compression cell (2) for producing a compressed gas stream, and a separation unit (200) for separating oil from the compressed gas stream, in particular exiting an outlet (9) of the compression cell (2), wherein the separation unit (200) is in fluid communication with the compression cell (2) and is configured to separate oil from the compressed gas stream exiting an outlet (9) of the compression cell (2), and wherein the separation unit (200) comprises a first separator (204), in particular a centrifugal separator, and a second separator (202), in particular a deceleration separator, wherein the second separator is positioned downstream of the first separation in the direction of the compressed gas stream.

2. The rotary compressor (100) according to claim 1, characterized in that the rotary compressor (100) further comprises a filter (108) for separating oil from the compressed gas stream, wherein the filter (108) is positioned downstream of the separation unit (200) in the direction of the compressed gas stream.

3. The rotary compressor (100) according to claim 2, characterized in that the separation unit (200), in particular the second separator (202), is further in fluid communication with the filter (108) using a connecting channel (127).

4. The rotary compressor (100) according to any one of claims 1 to 3, characterized in that the separation unit (200), in particular the first separator (201) and / or the second separator (202), is configured to direct the oil, once separated from the compressed gas stream, into an oil sump (112) of the rotary compressor (100).

5. The rotary compressor (100) according to any one of the preceding claims, characterized in that the separation unit (200) comprises a first end (203), a second end (204) and a body (205) extending between the first and second ends (203, 204), the compressed gas stream being configured to flow from the first end (203) towards the second end (204), wherein the first separator (201) is configured to be disposed at an outer periphery of the body (205), and / or wherein the second separator (202) is configured to be disposed in an interior of the body (205) near to the second end (204), in particular the second separator (202) comprises a deceleration chamber (209) and a transition chamber (210).

6. The rotary compressor (100) according to claim 5, characterized in that the second separator (202) is disposed within the body (205), downstream of a hollow chamber (208) formed in the body (205) in the direction of the compressed gas stream.

7. The rotary compressor (100) according to claims 5 or 6, characterized in that wherein the hollow chamber (208), the deceleration chamber (209) and the transition chamber (210) are in fluid communication, and wherein the deceleration chamber (209) is downstream of the hollow chamber (208), and the transition chamber (210) is downstream of the deceleration chamber (209) in the direction of the compressed gas stream.

8. The rotary compressor (100) according to any one of the preceding claims, characterized in that the first separator (201), in particular centrifugal separator, is configured to separate oil particles from the compressed gas stream by utilizing centrifugal forces generated through swirling motion.

9. The rotary compressor (100) according to claim 7, characterized in that the first separator (201) comprises a projecting element (206), in particular a helical element, and a grooved channel (207), in particular helical channel, both of which are disposed around the outer periphery of the body (205) of the separation unit (200), wherein the projecting element (206) is configured to guide the compressed gas stream along the grooved channel (207), thereby generating the centrifugal forces for accumulating the oil particles in the grooved channel (207).

10. The rotary compressor (100) according to claims 8 or 9, characterized in that the oil particles accumulated in the grooved channel (207) are configured to drain to an oil sump (112) of the rotary compressor (100) by gravity once they coalesce to a mass that allows them to detach from the grooved channel (207). And to pass through the gap....

11. The rotary compressor (100) according to any one of the preceding claims, characterized in that the second separator (202), in particular a deceleration chamber (209), comprises a base plate (211) and a plurality of openings (212) for further separating oil particles from the compressed gas stream received from the first separator (201).

12. The rotary compressor (100) according to any one of the preceding claims, characterized in that the rotary compressor (100) further comprises an oil return collecting chamber (129) communicating with an oil return bore (128) for returning the oil particles separated using the filter (108) into the compression cell (102) of the rotary compressor (100).

13. A separation unit (200) for a rotary compressor (100) of an air treatment system of a vehicle, in particular an electric vehicle and / or a hybrid vehicle, the separation unit (200) comprising a first separator (201) and a second separator (202) for separating oil particles from a compressed gas stream in two stages, wherein the second separator (202) is downstream of the first separator (201) in the direction of the compressed gas stream, preferably the first separator (201) comprising a centrifugal separator and being configured to separate oil using centrifugal forces in a first stage and the second separator (202) comprising a deceleration chamber (209) for further separating and collecting oil particles from the compressed gas stream in a second stage.

14. The separation unit (200) of claim 13, characterized in that the separation unit (200) is configured to be disposed between a compression cell (102) and a third separator, preferably a filter (108), in the direction of the compressed gas stream.

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