JP2019210930A - Blow-by gas device for engine with supercharger - Google Patents

Abstract

To improve the lubricity of a bearing part of a supercharger.SOLUTION: A blow-by gas device 70 for an engine with supercharger includes a blow-by gas passage 71 for introducing blow-by gas via a PCV valve 72 into an intake passage 30. A drive type supercharger 34 has supercharging rotors 341, 342 provided integrally with rotary shafts 81, 82 journaled by bearing parts 83, 84, respectively. Space parts 34f, 34h consisting of clearances communicating with the bearing parts 83, 84 are connected to communication paths 73, 74 branching from the blow-by gas passage 71 at its portion downstream of the PCV valve 72, respectively.SELECTED DRAWING: Figure 6

Description

  The disclosed technology relates to a blow-by gas device for a supercharged engine.

  Patent Document 1 discloses an intake device for a supercharged engine. There, there is described a configuration in which a blow-by gas introduction part for introducing blow-by gas is connected to a branch part of a supercharger bypass passage.

  Generally, a drive supercharger includes a pair of supercharged rotors inside a supercharger main body. These supercharged rotors are rotatably supported via a plurality of bearing portions by bearings.

Japanese Patent Laid-Open No. 04-203213

  In Patent Document 1, EGR (Exhaust Gas Recirculation) gas made of exhaust gas is introduced into an intake passage upstream of a drive supercharger. EGR gas is mixed with dust such as soot and / or condensed water. Accordingly, dust or the like may adversely affect the bearing portion of the supercharger and the sealing material disposed adjacent to the bearing portion.

  For this reason, it is important to ensure the lubricity of each bearing part and each sealing material and to ensure these sealing properties.

  Therefore, a main object of the disclosed technique is to improve the lubricity of the bearing portion and the sealing material of the supercharger. Furthermore, there exists in suppressing mixing of the dust etc. of the bearing part of a supercharger.

  The disclosed technology relates to a blow-by gas device (also simply referred to as a blow-by gas device) for a supercharged engine having a drive supercharger in a downstream portion of a throttle valve in an intake passage.

  The blow-by gas device is connected between an engine body and a PCV valve, a portion of the intake passage located between the throttle valve and the drive supercharger, and is discharged from the engine body. And a blow-by gas passage for introducing the blow-by gas into the intake passage through the PCV valve. The PCV (Positive Crankcase Ventilation) valve is a known valve that varies the flow rate of blow-by gas.

  The driven supercharger is provided integrally with a supercharger main body having a rotor chamber formed therein, a rotary shaft pivotally supported by a bearing portion installed in the supercharger main body, and the rotary shaft. And a supercharged rotor rotatably disposed inside the rotor chamber. The said supercharger main body has the space part which consists of the clearance gap which leads to the said bearing part. And the said space part is connected to the communicating path branched from the downstream part of the said PCV valve in the said blow-by gas path.

  According to this blow-by gas apparatus, the communication passage branches off from the downstream portion of the PCV valve in the blow-by gas passage, and the communication passage is connected to a space portion provided in the vicinity of the bearing portion of the drive supercharger. ing. The bearing portion communicates with the rotor chamber, and the space portion communicates with the bearing portion.

  For this reason, when the drive supercharger is not supercharged, the rotor chamber is not pressurized, so that the internal pressure of the space portion becomes relatively low. Accordingly, blow-by gas is introduced into the space through the blow-by gas passage and the communication passage. Blow-by gas means gas that leaks from the combustion chamber of the engine. Therefore, blow-by gas contains oil mist. The oil mist contained in the blow-by gas improves the lubricity of the bearing portion (seal material).

  On the other hand, when the drive supercharger is supercharging, the rotor chamber is pressurized. Therefore, the internal pressure of the space portion of the drive supercharger increases. When the internal pressure of the space portion becomes relatively high, even if dust or the like is mixed into the bearing portion, it is sucked into the blow-by gas passage through the communication passage. Accordingly, it is possible to suppress the dust and the like in the bearing portion from being mixed.

  In the blow-by gas device, the supercharger main body further includes a sealing material that closes a gap between the bearing portion and the rotor chamber, and the space portion is adjacent to the sealing material and the rotating shaft. It is good also as the cyclic | annular space formed in the circumference | surroundings.

  According to this, the oil mist which blowby gas contains is supplied to the space part which consists of cyclic | annular space. Accordingly, the lubricity of the sealing material and the bearing portion is improved. The sealing performance is also improved. If the internal pressure of the space portion becomes relatively high, dust or the like mixed in the bearing portion is sucked into the blow-by gas passage. Therefore, mixing of dust or the like in the bearing portion of the supercharger can be suppressed.

  In the blow-by gas device, the bearing is located on the suction side of the drive supercharger, and the space is formed by an annular step provided in the supercharger main body and the sealing material. It is good as well.

  According to this, it is possible to improve the lubricity and the like of the bearing portion and the sealing material located on the suction side.

  In the blow-by gas device, the bearing portion is located on a discharge side of the drive supercharger, and the space portion is disposed between the sealing material and a sealing material arranged to face the sealing material. It may be formed.

  According to this, it is possible to improve the lubricity and the like of the bearing portion and the sealing material located on the discharge side and to suppress the mixing of dust and the like.

  The space part of the blow-by gas device may be connected to a communication path communicating with the upstream side of the PCV valve.

  The internal pressure on the upstream side of the PCV valve is higher than the internal pressure on the downstream side of the PCV valve. Accordingly, if the space portion is connected to the communication passage communicating upstream of the PCV valve, the pressure difference becomes larger than the connection to the communication passage branched from the downstream portion of the PCV valve, and the internal pressure of the space portion is further increased. Can be made relatively low. As a result, blow-by gas can be stably introduced into the space. The lubricity and the like of the bearing portion and the seal material are further improved.

  In this case, the blow-by gas is discharged through an oil separator chamber provided in the engine body, the communication path communicates with the oil separator chamber, and the amount of the blow-by gas flowing into the space is reduced. It is preferable to have a flow rate suppressing part to be suppressed.

  In the oil separator chamber, blow-by gas containing oil mist is generated by gas-liquid separation. Therefore, if the space portion is connected to a communication passage communicating with the oil separator chamber, oil can be efficiently supplied to the space portion. The lubricity and the like of the bearing portion and the seal material are further improved.

  A large amount of blow-by gas can be introduced into the space portion by connecting the space portion to the communication passage communicating with the oil separator chamber. If blow-by gas is excessively introduced into the space, the amount of intake air may vary due to blow-by gas entering the rotor chamber. If the intake air amount fluctuates, the engine output may decrease. Such a malfunction can be suppressed by suppressing the inflow amount of blow-by gas at the flow rate suppression unit.

  The communication path may further include a backflow suppression unit that suppresses the backflow of the blow-by gas to the oil separator chamber. For example, a check valve can be used as the backflow suppression unit.

  If the backflow of blow-by gas is suppressed, blow-by gas can be more stably introduced into the space. A check valve is effective because it can prevent the backflow of blow-by gas.

  It is preferable to combine such communication paths depending on the engine specifications.

  For example, the drive-type supercharger includes a supercharger body having a rotor chamber formed therein, a pair of bearing portions installed on each of the suction side and the discharge side of the drive-type supercharger, and the pair of A rotating shaft that is pivotally supported by the bearing portion, and a supercharged rotor that is provided integrally with the rotating shaft and that is rotatably disposed inside the rotor chamber. A suction-side space portion formed by a gap communicating with the bearing portion on the suction side, and a discharge-side space portion formed by a gap communicating with the bearing portion on the discharge side, wherein the suction-side space portion is formed from the PCV valve. Also, it is preferable that the discharge side space is connected to a second communication path branched from a downstream portion of the PCV valve in the blow-by gas path.

  If it does so, a 1st communicating path will become a comparatively high pressure rather than a 2nd communicating path. Therefore, blow-by gas is more stably introduced into the suction side space than in the discharge side space. As a result, the lubricity and the like of the bearing portion on the suction side and the sealing material can be stably improved.

  For the discharge-side bearing portion, by utilizing the pressure balance at the time of non-supercharging, the lubrication and the like can be improved, and the mixing of dust and the like can be suppressed by the suction effect.

  According to the disclosed technology, it is possible to improve the lubricity and the like of the bearing portion of the supercharger and the sealing material. Further, it is possible to suppress mixing of dust and the like in the bearing portion of the supercharger.

It is a typical lineblock diagram showing the engine of an embodiment. It is a schematic top view which shows the specific structure of an intake unit. FIG. 3 is a schematic front view of the intake unit viewed from the direction of arrow A shown in FIG. 2. FIG. 3 is a schematic rear view of the intake unit viewed from the direction of arrow B shown in FIG. 2. (B) is a longitudinal cross-sectional view of a supercharger. (A) is sectional drawing in the Va-Va line | wire of (b), (c) is sectional drawing in the Vc-Vc line | wire of (b). It is a schematic diagram which shows the connection of a supercharger and a blow-by gas reduction system. (A) is a schematic top view which shows concretely the structure of the principal part of a blow-by gas passage. (B) is a schematic rear view corresponding to (a). It is the schematic which shows the flow of the intake air at the time of supercharging. It is the schematic which shows the flow of the intake at the time of non-supercharging. It is a typical block diagram which shows the engine of an application example. It is a schematic top view which shows the specific structure of the intake unit in an application example. It is a schematic diagram which shows the connection of the supercharger and blow-by gas reduction system in an application example.

  Hereinafter, embodiments of the disclosed technology will be described in detail based on the drawings. However, the following description is merely illustrative in nature and does not limit the present invention, its application, or its use.

  FIG. 1 shows a main configuration of an engine 1 (also simply referred to as engine 1) provided with a supercharger 34. A blow-by gas apparatus to which the disclosed technology is applied is incorporated in the engine 1.

  2 to 4 show a specific structure of the intake unit 3 provided in the engine 1. FIG. 2 is a view of the intake unit 3 as viewed from above. FIG. 3 is a view of the intake unit 3 as viewed from the direction of arrow A (front) shown in FIG. FIG. 4 is a view of the intake unit 3 as seen from the direction (rear) of the arrow B shown in FIG.

  The engine 1 is, for example, a four-stroke internal combustion engine mounted on an automobile (vehicle). The engine 1 includes a drive (mechanical) supercharger 34. The fuel of the engine 1 is not particularly limited. In this embodiment, the fuel of the engine 1 is gasoline.

  The engine 1 includes four cylinders 11 arranged in a row, although detailed illustration is omitted. The engine 1 is a so-called in-line 4-cylinder horizontal engine 1. Four cylinders 11 are mounted on the engine 1 so as to be aligned along the vehicle width direction.

  Thereby, the left-right direction of the engine 1 which is the direction (cylinder row direction) in which the four cylinders 11 are arranged substantially coincides with the vehicle width direction. In the engine 1, the cylinder row direction matches the direction in which the crankshaft 15 extends.

  Each figure shows directions such as up, down, left and right. Unless otherwise specified, “front” refers to the front side of the automobile. “Rear” refers to the rear side of an automobile. “Left” refers to one side in the vehicle width direction. “Right” refers to the other side in the vehicle width direction. Further, “up” refers to the upper side of the state in which the engine 1 is mounted on an automobile. “Lower” refers to the lower side.

(Schematic configuration of engine 1)
The engine 1 includes an engine body 10 having four cylinders 11, an intake passage 30 that is disposed on the front side of the engine body 10 and communicates with each cylinder 11 via an intake port 18, and a rear side of the engine body 10. And an exhaust passage 50 that is disposed and communicates with each cylinder 11 via the exhaust port 19.

  The intake passage 30 constitutes the intake unit 3. The intake unit 3 includes a plurality of passages through which intake air (gas such as air) flows and devices such as an air cleaner 31, a supercharger 34, an intercooler 36, and a surge tank 38 disposed in the middle of these passages. It is configured in combination. The engine body 10 burns an air-fuel mixture made up of intake air supplied through the intake unit 3 and fuel in combustion chambers 16 formed in the cylinders 11. The engine body 10 exhausts exhaust gas generated by combustion through the exhaust passage 50.

  Specifically, the engine body 10 includes a cylinder block 12 and a cylinder head 13 placed on the cylinder block 12. Four cylinders 11 are formed inside the cylinder block 12. These cylinders 11 are arranged along the direction in which the crankshaft 15 extends (only one cylinder is shown in FIG. 1).

  A piston 14 is slidably inserted in each cylinder 11. Each piston 14 is connected to a crankshaft 15 via a connecting rod 141. A combustion chamber 16 is defined by the piston 14, the cylinder 11, and the cylinder head 13. The “combustion chamber” here is not limited to the meaning of only the space formed when the piston 14 reaches compression top dead center. The term “combustion chamber” is used in a broad sense.

  For example, two intake ports 18 are formed in each cylinder 11 in the cylinder head 13 (only one intake port 18 is shown in FIG. 1). The two intake ports 18 are adjacent to each other in the cylinder row direction and communicate with the corresponding cylinders 11 respectively.

  An intake valve 21 is disposed in each of the two intake ports 18. The intake valve 21 opens and closes between the combustion chamber 16 and each intake port 18. The intake valve 21 is opened and closed at a predetermined timing by an intake valve mechanism.

  As shown in FIG. 1, the intake valve mechanism has a variable valve mechanism 23. The variable valve mechanism 23 is configured to continuously change the rotation phase of the intake camshaft within a predetermined angle range. Thereby, the valve opening timing and valve closing timing of each intake valve 21 change continuously.

  Further, for example, two exhaust ports 19 are formed for each cylinder 11 in the cylinder head 13 (FIG. 1 shows only one exhaust port 19). The two exhaust ports 19 are adjacent to each other in the cylinder row direction and communicate with the corresponding cylinders 11.

  Exhaust valves 22 are respectively disposed in the two exhaust ports 19. The exhaust valve 22 opens and closes between the combustion chamber 16 and each exhaust port 19. The exhaust valve 22 is opened and closed at a predetermined timing by an exhaust valve mechanism.

  As shown in FIG. 1, the exhaust valve mechanism has a variable valve mechanism 24. The variable valve mechanism 24 is configured to continuously change the rotational phase of the exhaust camshaft within a predetermined angular range. Thereby, the valve opening timing and the valve closing timing of each exhaust valve 22 change continuously.

  An injector 6 is attached to the cylinder head 13 for each cylinder 11. Each injector 6 is, for example, a multi-injection type fuel injection valve. The injector 6 directly injects fuel into each combustion chamber 16.

  A fuel supply system 61 is connected to each injector 6. The fuel supply system 61 includes a fuel tank 63 that stores fuel, and a fuel supply path 62 that connects the fuel tank 63 and the injector 6 to each other. A fuel pump 65 and a common rail 64 are interposed in the fuel supply path 62.

  A spark plug 25 is attached to the cylinder head 13 for each cylinder 11. The tip of the spark plug 25 faces the inside of the combustion chamber 16. By the operation of the spark plug 25, the air-fuel mixture in the combustion chamber 16 is forcibly ignited.

(Intake unit 3)
An air cleaner 31 that filters fresh air is disposed at the upstream end of the intake passage 30. The surge tank 38 is a container-like device that temporarily stores intake air. The surge tank 38 is disposed at the downstream end of the intake passage 30, that is, at the upstream portion of the intake port 18 in the intake passage 30. A throttle valve 32 is disposed in a portion of the intake passage 30 downstream of the air cleaner 31. The opening degree of the throttle valve 32 is controlled according to the operating state of the engine 1. Thereby, the amount of fresh air introduced into the combustion chamber 16 is adjusted.

  A supercharger 34 is disposed in a portion of the intake passage 30 downstream of the throttle valve 32. The supercharger 34 supercharges the intake air introduced into each combustion chamber 16. The supercharger 34 is driven (mechanical or drive type) by the engine 1 (specifically, power transmitted from the crankshaft 15). The supercharger 34 is configured as, for example, a two-shaft rotor type roots blower.

  An electromagnetic clutch 34 a and a drive pulley 34 d are interposed between the supercharger 34 and the crankshaft 15. An annular timing belt is wound around the drive pulley 34d and the crankshaft 15. Thereby, the drive pulley 34d and the crankshaft 15 rotate in conjunction with each other. The supercharger 34 may be an electric type driven by electricity.

  The electromagnetic clutch 34a connects between the supercharger 34 and the crankshaft 15 to transmit driving force, or interrupts driving force transmission. The ECU 7 (control device) switches between disconnection and connection of the electromagnetic clutch 34a. By doing so, the supercharger 34 is switched between the on state and the off state.

  That is, the engine 1 switches between the ON state and the OFF state of the supercharger 34, thereby supercharging the intake air introduced into the combustion chamber 16 (supercharging operation) and overcharging the intake air introduced into the combustion chamber 16. It is possible to switch between non-supply operation (natural intake operation). Details of the supercharger 34 will be described later.

  The intercooler 36 is disposed at a downstream portion of the supercharger 34 in the intake passage 30. The intercooler 36 exchanges heat with the intake air that has passed through the supercharger 34, and cools the intake air compressed by the supercharger 34. The intercooler 36 is, for example, a water cooling type.

  The intake passage 30 is a first passage 33 that constitutes a portion downstream of the throttle valve 32 and upstream of the supercharger 34, and a portion downstream of the supercharger 34 and upstream of the intercooler 36. , A second passage 35 that is downstream of the intercooler 36 and upstream of the surge tank 38, and a downstream side of the surge tank 38, And an independent passage 39 constituting an upstream portion.

  The independent passage 39 is formed to branch into a plurality from the surge tank 38 for each intake port 18. The first passage 33, the second passage 35, the third passage 37, and the independent passage 39 constitute a main intake passage 30 </ b> A that is the main body of the intake passage 30.

  In addition to the main intake passage 30 </ b> A, the intake passage 30 is provided with a bypass passage 40 that bypasses the supercharger 34 and the intercooler 36. Specifically, the bypass passage 40 is branched from a portion in the middle of the first passage 33 (upstream branching portion 33a) and connected to the surge tank 38 (downstream branching portion).

  A bypass valve 41 that changes the cross-sectional area of the bypass passage 40 is disposed in the bypass passage 40. The bypass valve 41 changes the flow path cross-sectional area of the bypass passage 40 according to the operating state of the engine 1. Thereby, the bypass valve 41 adjusts the flow rate of the intake air flowing through the bypass passage 40.

  The intake passage 30 is provided with an evaporated fuel passage 66 for introducing the evaporated fuel generated in the fuel tank 63 into the intake passage 30. The evaporated fuel passage 66 is connected to a purge valve 68 disposed in the first passage 33 from above the fuel tank 63 via a canister 67. The canister 67 is a container that temporarily stores evaporated fuel.

(Exhaust passage 50)
The exhaust passage 50 is connected to the rear side of the engine body 10 opposite to the intake passage 30. Although illustration is omitted, the upstream end portion of the exhaust passage 50 constitutes an independent passage branched for each cylinder 11. These independent passages are connected to the exhaust port 19 of each cylinder 11.

  In the exhaust passage 50, an exhaust purification system having one or more catalytic converters 51 is disposed. The catalytic converter 51 includes a three-way catalyst, and is disposed adjacent to the downstream side of the exhaust port 19 in the exhaust passage 50 (so-called direct catalyst). The exhaust purification system is not limited to the configuration including only the three-way catalyst.

  An EGR passage 52 constituting an external EGR system is connected between the intake passage 30 and the exhaust passage 50. The EGR passage 52 introduces part of the exhaust gas into the intake passage 30. Specifically, the upstream end of the EGR passage 52 is connected to a portion of the exhaust passage 50 downstream of the catalytic converter 51 and communicates with the exhaust passage 50.

  On the other hand, the downstream end of the EGR passage 52 is configured to communicate with a portion upstream of the supercharger 34 in the intake passage 30 and downstream of the throttle valve 32 (details will be described later).

  A water-cooled EGR cooler 53 is disposed in the EGR passage 52. The EGR cooler 53 cools the exhaust gas flowing through the EGR passage 52. The flow rate of the exhaust gas flowing through the EGR passage 52 is adjusted by the EGR valve 54. The amount of cooled exhaust gas (external EGR gas) introduced into the intake passage 30 is adjusted by adjusting the opening of the EGR valve 54.

(Blow-by gas reduction system 70)
The engine 1 is provided with a blow-by gas reduction system 70. The blow-by gas reduction system 70 constitutes a blow-by gas device to which the disclosed technology is applied. The blow-by gas reduction system 70 introduces gas leaking from the combustion chamber 16 (blow-by gas) into the intake passage 30 and reduces it to the combustion chamber 16. Blow-by gas contains oil mist.

  Specifically, as shown in FIG. 1, a cylinder head cover 26 is installed on the upper portion of the cylinder head 13. A PCV (Positive Crankcase Ventilation) valve 72 is provided above the cylinder head cover 26. An oil separator chamber 27 is installed inside the cylinder head cover 26 (see FIG. 6).

  A gas leaking from the combustion chamber 16, that is, a blow-by gas is introduced into the oil separator chamber 27. Blow-by gas contains oil (engine oil). In the oil separator chamber 27, gas-liquid separation is performed. Thereby, most of the oil contained in the blow-by gas is separated. Therefore, the blow-by gas discharged through the oil separator chamber 27 contains oil mist.

  The PCV valve 72 is connected to a passage communicating with the oil separator chamber 27. The blow-by gas passage 71 constituting the blow-by gas reduction system 70 has an upstream end connected to the PCV valve 72. The PCV valve 72 varies the flow rate of blow-by gas flowing into the blow-by gas passage 71.

  The downstream end of the blow-by gas passage 71 is connected to the upstream portion of the bypass passage 40. The blow-by gas passage 71 has a first communication passage 73 connected to the suction side of the supercharger 34 and a second communication passage 74 connected to the discharge side of the supercharger 34. Details of the blow-by gas passage 71 will be described later.

(Supercharger 34)
As shown in FIG. 5, the supercharger 34 has a casing 34b (supercharger main body). A rotor chamber 343 and a gear chamber 344 are formed in the casing 34b. Inside the rotor chamber 343 and the gear chamber 344, a pair of rotating shafts 81 and 82 each including a driving-side rotating shaft and a driven-side rotating shaft are disposed so as to extend in parallel to the cylinder row direction.

  The casing 34b is provided with a pair of bearing portions 83 and 84 including a suction side bearing portion and a discharge side bearing portion. Each of the rotating shafts 81 and 82 is rotatably supported by the pair of bearing portions 83 and 84.

  As shown in FIG. 6, a small-capacity bearing chamber 345 is provided on the left side of the rotor chamber 343 so as to protrude from the casing 34b. The bearing chamber 345 is a part of the casing 34b. The bearing chamber 345 accommodates the end portions of the rotary shafts 81 and 82. The bearing chamber 345 accommodates a ball bearing that constitutes the suction side bearing portion 83.

  End portions of the rotary shafts 81 and 82 that protrude from the rotor chamber 343 to the bearing chamber 345 through the shaft hole 345a are pivotally supported via the ball bearings. The bearing chamber 345 is provided with a sealing material (suction side sealing material 91). The suction side sealing material 91 closes the gap between the shaft hole 345a and the rotary shafts 81 and 82.

  The gear chamber 344 is disposed adjacent to the right side of the rotor chamber 343. The rotary shafts 81 and 82 protrude from the rotor chamber 343 to the gear chamber 344 through the shaft holes 344a. The gear chamber 344 is also provided with a sealing material that closes the gap between the shaft hole 344a and the rotary shafts 81 and 82. Unlike the bearing chamber 345, the gear chamber 344 is provided with two sealing materials 92 and 93. This will be described later.

  A gear 346 is accommodated in the gear chamber 344. The gear 346 rotates the drive-side rotary shaft 81 and the driven-side rotary shaft 82 in conjunction with each other. The discharge-side bearing portion 84 is housed in the gear chamber 344 together with the gear 346. The gear chamber 344 is filled with an appropriate amount of lubricating oil.

  In the rotor chamber 343, the first rotor 341 and the second rotor 342 are accommodated so as to partially mesh with each other. The first rotor 341 is integrally fixed to the driven side rotation shaft 82. The second rotor 342 is integrally fixed to the drive-side rotating shaft 81. The drive-side rotary shaft 81 extends longer than the driven-side rotary shaft 82, protrudes from the gear chamber 344, and is connected to the electromagnetic clutch 34a.

  A suction port 34c communicating with the rotor chamber 343 is opened at the left end of the casing 34b, as shown in the cross-sectional view (c) indicated by the line Vc-Vc on the right side of FIG. On the other hand, a discharge port 34e that opens in a V shape or a triangle shape that exposes the rotor chamber 343 is opened on the front side surface of the casing 34b.

  The suction port 34 c communicates with the first passage 33. The discharge port 34e communicates with the second passage 35. As the first rotor 341 and the second rotor 342 rotate, the intake air flowing through the first passage 33 is sucked into the rotor chamber 343 through the suction port 34c. The intake air drawn into the rotor chamber 343 is sent out toward the right side and compressed. The compressed intake air is discharged from the discharge port 34e.

(Layout of intake unit 3)
As shown in FIG. 2, the intake unit 3 is disposed along the front side of the engine body 10, specifically, along the front surfaces of the cylinder head 13 and the cylinder block 12. In particular, the supercharger 34 and the intercooler 36 are arranged in the vicinity of the upstream end of the intake port 18 so as to increase the supercharging response.

  The supercharger 34 is disposed on the front side of the engine main body 10 so as to sandwich a horizontally long surge tank 38 extending in the left-right direction. Between the rear part of the supercharger 34 and the front part of the engine body 10, there is a gap corresponding to the dimension of the surge tank 38. The first passage 33 extends on the left side of the supercharger 34 in the cylinder row direction. The first passage 33 is connected to the left end of the supercharger 34 (the end where the suction port 34c is open).

  As shown in FIG. 3, the supercharger 34 and the intercooler 36 are arranged in the vertical direction in this order. And these are adjacent up and down. The second passage 35 extends substantially in the vertical direction so as to connect the front part of the supercharger 34 having the discharge port 34e and the front part of the intercooler 36.

  As shown in FIGS. 2 and 4, the surge tank 38 is disposed in a gap between the rear portion of the supercharger 34 and the plurality of independent passages 39. The third passage 37 extends so as to pass below the supercharger 34. The intercooler 36 is located below the surge tank 38. The rear part of the intercooler 36 and the bottom part of the surge tank 38 are connected by a third passage 37.

  The bypass passage 40 branches from the upstream branch portion 33a of the first passage 33 and extends upward, and then extends to the right. The downstream end of the bypass passage 40 is bifurcated and connected to the upper portion of the surge tank 38 (see FIGS. 2 and 4).

(Use of blow-by gas to the turbocharger 34)
The external EGR gas includes soot, dust such as oxides, water vapor, and the like. The water vapor and the like flow into the rotor chamber 343 of the supercharger 34 as the external EGR gas is introduced into the intake air. When the EGR cooler 53 cools the water vapor, it becomes condensed water in the EGR passage 52 and the bypass passage 40, and flows into the first passage 33 from the bypass passage 40 and may flow into the rotor chamber 343 of the supercharger 34. is there.

  When these dust and condensed water flow into the rotor chamber 343 of the supercharger 34, the dust and the condensed water may act on the bearing portion and the seal material and may be deteriorated. Therefore, in this engine 1, the blow-by gas reduction system 70 sucks the intake air around the bearing portion and the seal material, or supplies oil to the periphery of the bearing portion and the seal material, depending on the operating state of the engine 1. It is devised so that it can.

  Specifically, as shown in FIG. 1, a first communication path 73 and a second communication path 74 that branch from a portion of the blow-by gas path 71 on the downstream side of the PCV valve 72 are provided. As shown in FIG. 6, the first communication passage 73 and the second communication passage 74 pass through the casing 34b of the supercharger 34 and reach the vicinity of the bearing portions 83 and 84 on the suction side and the discharge side. Yes. The first communication path 73 and the second communication path 74 are in communication with a space portion (suction side annular space portion 34f, discharge side annular space portion 34h) formed by a gap communicating with the bearing portions 83 and 84.

  FIG. 6 schematically shows a main part of the blow-by gas passage 71. FIG. 7 specifically shows the main part of the blow-by gas passage 71. As shown in these drawings, the downstream end of the blow-by gas passage 71 is composed of a downstream introduction passage 71a, an upstream introduction passage 71b, a first branch passage 73a, a second branch passage 74a, and the like.

  The downstream introduction path 71a is connected to a portion of the bypass passage 40 near the upstream branch portion 33a. The blow-by gas is introduced into the intake passage 30 from an introduction port (blow-by gas introduction port 75) that opens at a connection site of the downstream-side introduction path 71a.

  And the 1st branch path 73a and the 2nd branch path 74a have branched from the site | part upstream of the blow-by gas introduction port 75 in the downstream introduction path 71a. The first branch path 73a is located upstream of the second branch path 74a. The first branch path 73 a communicates with the first communication path 73. The second branch path 74 a communicates with the second communication path 74.

  The upstream introduction path 71b continues in a state intersecting with the upstream side of the downstream introduction path 71a. Specifically, the upstream introduction path 71b extends in the cylinder row direction. The downstream introduction path 71a branches so as to bend from the downstream side of the upstream introduction path 71b, and extends in a lateral direction substantially perpendicular to the cylinder row direction. The first branch path 73a extends in the cylinder row direction from the bent portion of the upstream side introduction path 71b and the downstream side introduction path 71a so as to be connected straight to the upstream side introduction path 71b.

  On the other hand, the second branch path 74a extends in the cylinder row direction in parallel with the first branch path 73a from the middle of the downstream side introduction path 71a. The upstream introduction path 71b is configured by a pipe having a larger diameter than the first branch path 73a and the second branch path 74a.

  Such an upstream introduction path 71b, a downstream introduction path 71a, and a first branch path 73a constitute an oil separation supply unit OP. The oil separation supply unit OP separates the oil from the blow-by gas, and in particular supplies the oil to the first communication path 73. The upstream introduction path 71b constitutes a straight portion, and the downstream introduction path 71a constitutes a cross portion.

  As shown in FIGS. 2 and 4, the first communication passage 73 and the second communication passage 74 are disposed between the supercharger 34 and the bypass passage 40 disposed above the supercharger 34. The oil separation supply unit OP is disposed in a slight gap between the first passage 33 and the bypass passage 40. The oil separation supply unit OP is configured compactly by the blow-by gas passage 71.

  Thereby, the layout of the blow-by gas passage 71 and the communication passages 73 and 74 is configured to be organic and compact. The communication passages 73 and 74 are arranged in the cylinder row direction. Therefore, the intake air flows smoothly and the layout can be made compact.

  As shown in FIGS. 5 and 6, suction-side annular spaces 34f each having an annular gap are provided around shaft holes 345a facing the respective bearing chambers 345 of the casing 34b. As shown in an enlarged view in FIG. 6, the suction side annular space 34f is provided with an annular step 34f1 having a diameter larger than that of the shaft hole 34a.

  The suction side sealing material 91 is adjacent to and faces the suction side annular space portion 34f through the annular step portion 34f1. The annular step portion 34f1 increases the volume of the suction side annular space portion 34f. The annular step portion 34f1 can be formed by cutting an inner portion of each sealing material 91 in the casing 34b using an end mill or the like.

  As shown in the sectional view (c) of FIG. 5, the two suction-side annular spaces 34f, 34f are connected to each other by a single first connection path 34g formed of a vertical hole. Accordingly, the two suction-side annular spaces 34f and 34f can be easily communicated by drilling.

  On the other hand, a discharge-side annular space 34h made of an annular gap is also provided around each shaft hole 344a facing the gear chamber 344 of the casing 34b. Around each shaft hole 344a facing the gear chamber 344, two sealing materials (an outer sealing material 92 and an inner sealing material 93) are arranged to face each other with a gap therebetween. The outer seal material 92 is located on the gear chamber 344 side, and the inner seal material 93 is located on the rotor chamber 343 side.

  A discharge-side annular space 34 h is provided between the outer sealing material 92 and the inner sealing material 93. Each of the outer sealing material 92 and the inner sealing material 93 is adjacent to and faces the discharge-side annular space 34h. As in the cross-sectional view (a) shown on the left side in FIG. 5, the two discharge-side annular spaces 34h and 34h are also connected to each other by a second connection path 34i formed of a vertical hole, like the suction-side annular space 34f. Has been.

  The first communication path 73 is connected to each suction-side annular space 34f through the first connection path 34g. The second communication path 74 is connected to each discharge-side annular space 34h via the second connection path 34i.

  As described above, the first communication passage 73 and the second communication passage 74 that branch from the blow-by gas passage 71 through the oil separation supply section OP are respectively connected to the suction-side bearing portion 83 and the discharge-side bearing portion in the supercharger 34. The suction side annular space portion 34f and the discharge side annular space portion 34h provided in the vicinity of each of the 84 communicate with each other. Therefore, according to the operating state of the engine 1, the intake air around the bearing portions 83, 84 and the seal materials 91, 92, 93 is sucked or the periphery of the bearing portions 83, 84, and the seal materials 91, 92, 93 is Or supply oil to An example of this will be described in the case of supercharging and non-supercharging (natural intake).

(When supercharging)
FIG. 8A shows the flow of intake air during supercharging in the intake passage 30. For example, when acceleration is requested because the accelerator is stepped on, the ECU 7 operates the supercharger 34 (that is, the electromagnetic clutch 34a is connected) while the automobile is running, and the opening degree of the bypass valve 41 is appropriately set. adjust.

  At this time, the throttle valve 32 is normally adjusted to be fully open, and fresh air is introduced into the intake passage 30 without load. Further, the opening degree of the EGR valve 54 is appropriately adjusted according to the operating state of the engine 1. By doing so, the external EGR gas is introduced into the intake passage 30. Further, blow-by gas is also introduced into the intake passage 30 by appropriately adjusting the opening degree of the PCV valve 72.

  Thus, fresh air, external EGR gas, and blow-by gas (also simply referred to as intake air) are introduced into the combustion chamber 16 in a supercharged state through the main intake passage 30A. At this time, a part of the intake air that has passed through the supercharger 34 flows back upstream of the supercharger 34 through the bypass passage 40 by adjusting the opening degree of the bypass valve 41. The boost pressure of the intake air introduced into the combustion chamber 16 is adjusted by the reverse flow rate of the intake air.

  Thus, when the supercharger 34 is operating, the inside (discharge side) of the rotor chamber 343 is at a high pressure. Therefore, the internal pressure of the discharge-side annular space 34h that is located in the vicinity of the rotor chamber 343 and communicates with the rotor chamber 343 through the shaft hole 344a also increases in accordance with the supercharging pressure. Usually, the internal pressure of the discharge side annular space 34 h is higher than the internal pressure of the blow-by gas passage 71.

  Accordingly, dust and condensed water adhering to the periphery of the bearing portion 84 and the sealing materials 92 and 93 can be sucked into the blow-by gas passage 71 through the discharge-side annular space portion 34h and the second communication passage 74 together with the intake air. As a result, deterioration of the bearing portion 84 and the sealing materials 92 and 93 can be suppressed.

  On the other hand, when the supercharger 34 is operating, the inside (suction side) of the rotor chamber 343 tends to be at a low pressure. Therefore, the internal pressure of the suction-side annular space 34f that is located in the vicinity of the rotor chamber 343 and communicates with the rotor chamber 343 through the shaft hole 345a tends to be lowered in accordance with the supercharging pressure. In that case, the internal pressure of the suction side annular space 34 f is lower than the internal pressure of the blow-by gas passage 71.

  Then, blow-by gas is introduced into the suction side annular space 34f. Unlike the gear chamber 344, the suction-side annular space portion 34f leads to the bearing chamber 345 where oil is insufficient and lubrication is liable to occur. Therefore, by supplying blow-by gas containing oil to these, the lubricity and sealing performance of the suction side sealing material 91 and the lubricity of the suction side bearing portion 83 can be improved.

  If the inside (suction side) of the rotor chamber 343 is also raised similarly to the discharge side, dust and the like adhering to the periphery of the bearing portion 83 and the seal material 91 can be sucked out into the blow-by gas passage 71. In that case, deterioration of the bearing part 83 and the sealing material 91 can be suppressed.

(Non-supercharging)
FIG. 8B shows the flow of intake air in the intake passage 30 during non-supercharging (during natural intake). For example, when idling or coasting, the ECU 7 stops the operation of the supercharger 34 (that is, shuts off the electromagnetic clutch 34a) and fully opens the bypass valve 41.

  At this time, the opening degree of the throttle valve 32 is appropriately adjusted according to the operating state of the engine 1, and an appropriate amount of fresh air is introduced into the intake passage 30. Further, the external EGR gas is introduced into the intake passage 30 by appropriately adjusting the opening degree of the EGR valve 54 according to the operating state of the engine 1. Further, blow-by gas is also introduced into the intake passage 30 by appropriately adjusting the opening degree of the PCV valve 72.

  As a result, the intake air flowing through the intake passage 30 bypasses the supercharger 34 and is introduced into the combustion chamber 16 in a state of natural intake. In this way, when the supercharger 34 is not operating, the interior of the rotor chamber 343 is in a non-pressurized state. For this reason, the internal pressures of the suction-side annular space portion 34f and the discharge-side annular space portion 34h do not increase.

  Therefore, the difference between the internal pressure of the blow-by gas passage 71 and the internal pressure of each of the suction-side annular space portion 34f and the discharge-side annular space portion 34h is relatively small. Thereby, the flow of blow-by gas can change depending on the operating state of the engine 1.

  That is, due to a change in pressure balance accompanying the pumping action of the combustion chamber 16, the internal pressures of the suction side annular space 34f and the discharge side annular space 34h are higher than the internal pressure of the blow-by gas passage 71, or the suction side The internal pressure of each of the annular space portion 34f and the discharge-side annular space portion 34h may be higher than the internal pressure of the blow-by gas passage 71.

  For example, according to various studies by the inventors of the present application, during low load operation, the internal pressure (negative pressure) of the suction-side annular space portion 34f and the discharge-side annular space portion 34h is the pressure of the blow-by gas passage 71 (negative pressure). There is almost no difference. The pressure balance becomes delicate.

  Thus, depending on the operating state of the engine 1, blow-by gas may be introduced into the suction-side annular space portion 34f and the discharge-side annular space portion 34h. In that case, as schematically shown in FIG. 6, the blow-by gas is introduced into the suction-side annular space portion 34f and the discharge-side annular space portion 34h via the first branch passage 73a and the second branch passage 74a. .

  At this time, the first branch path 73a is linearly connected to the upstream side introduction path 71b (straight portion) extending linearly. Therefore, the oil mist contained in the blow-by gas easily flows into the first communication path 73 due to inertia. Blow-by gas that is lighter than oil mist tends to flow into the downstream introduction path 71a (cross section). As a result, the blow-by gas containing a relatively large amount of oil is distributed to the first communication path 73 and flows into the suction-side annular space 34f.

  As described above, the suction-side annular space 34f communicates with the bearing chamber 345 that is not sufficiently oily and is likely to be poorly lubricated. Therefore, the lubricity and sealability of the suction side sealing material 91 and the lubricity of the suction side bearing portion 83 can be improved.

<Application example>
FIG. 9 shows an application example of the disclosed technology.

  In the above-described embodiment, both the first communication path 73 connected to the suction-side annular space portion 34 f and the second communication passage 74 connected to the discharge-side annular space portion 34 h are the PCV valve 72 in the blow-by gas passage 71. It was branched from the downstream part. On the other hand, in this application example, the first communication path 73 communicating with the suction-side annular space 34f does not branch from the downstream portion of the PCV valve 72, but independently communicates with the upstream side of the PCV valve 72. Is configured to do.

  As described above, blow-by gas during non-supercharging is introduced or led out to the suction-side annular space portion 34f and the discharge-side annular space portion 34h depending on the operating state of the engine 1. The suction-side annular space 34f is preferably structured to improve the sealing performance and lubricity by introducing blow-by gas, in particular, rather than introducing blow-by gas and suppressing dust and the like.

  Therefore, depending on the specifications of the engine 1, it may be better to be able to introduce blow-by gas into the suction-side annular space 34f more stably. This application example is suitable for such an engine 1. According to this application example, the blow-by gas can be stably introduced into the suction-side annular space 34f without being affected by the operating state of the engine 1.

  As shown in FIG. 10, the first communication path 73 (also referred to as application first communication path 73 ') of this application example is not connected to the first branch path 73a. The applied first communication passage 73 ′ is installed so as to extend from the suction side portion of the supercharger 34 toward the cylinder head cover 26 through the vicinity of the bypass passage 40.

  Accordingly, as shown in FIG. 11, the first branch path 73a is lost. In this application example, the second branch path 74a and the second communication path 74 are configured in the same manner as in the above-described embodiment. Instead of the first branch path 73a, the second branch path 74a may be eliminated and the second communication path 74 may be connected to the first branch path 73a.

  The upstream side of the applied first communication path 73 ′ is directly connected to the cylinder head cover 26. Thereby, the applied first communication passage 73 ′ communicates with the oil separator chamber 27.

  An orifice 100 (an example of a flow rate suppressing unit) that reduces the cross-sectional area of the flow path is provided at the upstream end of the applied first communication path 73 ′. The orifice 100 creates a predetermined pressure difference between the upstream side and the downstream side. Thereby, the amount of blow-by gas flowing into the suction-side annular space 34f through the applied first communication passage 73 'is suppressed. The orifice 100 may be a throttle valve capable of adjusting the flow rate.

  When the amount of blow-by gas flowing into the suction-side annular space 34f increases, the amount of intake air may vary due to the blow-by gas entering the rotor chamber 343. That is, the application first communication passage 73 ′ is different from the first communication passage 73 branched from the blowby gas passage 71 and independently introduces blowby gas from the oil separator chamber 27 into the supercharger 34. For this reason, the amount of blow-by gas introduced into the supercharger 34 tends to increase.

  If the intake air amount fluctuates, the output of the engine 1 may decrease. By suppressing the inflow amount of blow-by gas at the orifice 100, such a problem can be suppressed.

  An upstream end portion of the applied first communication path 73 ′ is also provided with a check valve 101 (an example of a backflow suppressing portion) in order to suppress backflow of blow-by gas to the oil separator chamber 27. If the back flow of blow-by gas is suppressed, the blow-by gas can be more stably introduced into the suction-side annular space 34f without being affected by the operating state of the engine 1. The check valve 101 is effective because it can prevent the backflow of blow-by gas.

  As described above, according to this application example, the lubricity of the suction-side sealing material 91 and the bearing portion 83 that are likely to be poorly lubricated due to the structure can be stably improved. For the discharge-side bearing portion 84 that is less likely to be poorly lubricated, the lubricity is improved and the mixed dust and the like are sucked out to suppress the dust and the like from being mixed.

  The disclosed technology is not limited to the above-described embodiments and application examples. The disclosed technology includes various configurations other than these.

  For example, both the first communication path 73 and the second communication path 74 may be configured not to branch from the downstream portion of the PCV valve 72 but to communicate with the upstream side of the PCV valve 72. Further, depending on the engine specifications, only one of the first communication path 73 and the second communication path 74 may be provided.

  The backflow suppression unit is not essential. Further, the check valve 101 is preferable as the backflow suppressing unit, but is not limited thereto. Any device that prevents the backflow of blow-by gas can be used as a backflow suppression unit.

1 Engine 3 Intake Unit 10 Engine Body 27 Oil Separator Chamber 30 Intake Passage 30A Main Intake Passage 31 Air Cleaner 32 Throttle Valve 33 First Passage 33a Upstream Branch 34 Supercharger (Drive Supercharger)
34b Casing (supercharger body)
34f Inlet side annular space (space)
34h Discharge-side annular space (space)
341 First rotor (supercharged rotor)
342 Second rotor (supercharged rotor)
343 Rotor chamber 344 Gear chamber 35 Second passage 36 Intercooler 37 Third passage 38 Surge tank 39 Independent passage 40 Bypass passage 41 Bypass valve 50 Exhaust passage 51 Catalytic converter 52 EGR passage 53 EGR cooler 54 EGR valve 61 Fuel supply system 70 Blow-by Gas reduction system (blow-by gas equipment)
71 Blow-by gas passage 71a Downstream introduction passage 71b Upstream introduction passage 72 PCV valve 73 First communication passage (communication passage)
73a First branch path 74 Second communication path (communication path)
74a Second branch path 75 Blow-by gas inlet 81 Rotating shaft (drive side)
82 Rotating shaft (driven side)
83 Bearing (suction side)
84 Bearing (discharge side)
91 Suction side sealing material 92 Outer sealing material (seal material)
93 Inner seal material 100 Orifice (flow control part)
101 Check valve (backflow suppression part)

Claims (14)

A blow-by gas device for a supercharged engine equipped with a driven supercharger in a downstream portion of a throttle valve in an intake passage,
A PCV valve,
The blow-by gas, which is connected between the portion of the intake passage located between the throttle valve and the drive supercharger and the engine body, is discharged from the engine body through the PCV valve. A blow-by gas passage introduced into the intake passage;
With
The driven supercharger is
A turbocharger body having a rotor chamber formed therein;
A rotating shaft pivotally supported by a bearing portion installed in the supercharger body;
A supercharged rotor that is provided integrally with the rotary shaft and is rotatably arranged in the rotor chamber;
Have
The supercharger main body has a space portion formed by a gap communicating with the bearing portion,
The blow-by gas device for a supercharged engine, wherein the space portion is connected to a communication passage branched from a downstream portion of the PCV valve in the blow-by gas passage. The blow-by gas device for a supercharged engine according to claim 1,
The supercharger main body has a sealing material that closes a gap between the bearing portion and the rotor chamber,
The space part is a blow-by gas device for a supercharged engine, which is an annular space formed around the rotating shaft adjacent to the sealing material. The blow-by gas device for a supercharged engine according to claim 2,
The bearing is located on the suction side of the drive supercharger,
The space portion is a blow-by gas device for a supercharged engine, which is formed by an annular step provided in the supercharger main body and the sealing material. The blow-by gas device for a supercharged engine according to claim 2,
The bearing is located on the discharge side of the drive supercharger,
The space portion is a blow-by gas device for a supercharged engine, which is formed between the sealing material and a sealing material arranged to face the sealing material. A blow-by gas device for a supercharged engine equipped with a driven supercharger in a downstream portion of a throttle valve in an intake passage,
A PCV valve,
The blow-by gas, which is connected between the portion of the intake passage located between the throttle valve and the drive supercharger and the engine main body and is discharged from the engine main body, passes through the PCV valve. A blow-by gas passage introduced into the intake passage;
With
The driven supercharger is
A turbocharger body having a rotor chamber formed therein;
A rotating shaft pivotally supported by a bearing portion installed in the supercharger body;
A supercharged rotor that is provided integrally with the rotary shaft and is rotatably arranged in the rotor chamber;
Have
The supercharger main body has a space portion formed by a gap communicating with the bearing portion,
The blow-by gas device for an engine with a supercharger, wherein the space is connected to a communication path communicating upstream of the PCV valve. The blow-by gas device for a supercharged engine according to claim 5,
The blowby gas is discharged through an oil separator chamber provided in the engine body,
The blow-by gas device for a supercharged engine, wherein the communication passage communicates with the oil separator chamber and has a flow rate suppressing unit that suppresses an inflow amount of the blow-by gas into the space. The blow-by gas device for a supercharged engine according to claim 6,
The blow-by gas device for a supercharged engine, wherein the communication path further includes a back-flow suppressing unit that suppresses the back-flow of the blow-by gas to the oil separator chamber. The blow-by gas device for a supercharged engine according to claim 7,
The blow-by gas device for an engine with a supercharger, wherein the backflow suppression unit is a check valve. A blow-by gas device for a supercharged engine equipped with a driven supercharger in a downstream portion of a throttle valve in an intake passage,
A PCV valve,
The blow-by gas, which is connected between the portion of the intake passage located between the throttle valve and the drive supercharger and the engine main body and is discharged from the engine main body, passes through the PCV valve. A blow-by gas passage introduced into the intake passage;
With
The driven supercharger is
A turbocharger body having a rotor chamber formed therein;
A pair of bearings installed on each of the suction side and the discharge side of the drive supercharger;
A rotating shaft pivotally supported by the pair of bearing portions;
A supercharged rotor that is provided integrally with the rotary shaft and is rotatably arranged in the rotor chamber;
Have
The turbocharger body is
A suction side space formed by a gap communicating with the bearing on the suction side;
A discharge-side space consisting of a gap communicating with the bearing on the discharge side;
Have
The suction side space is connected to a first communication path communicating upstream of the PCV valve;
The blow-by gas device for an engine with a supercharger, wherein the discharge-side space is connected to a second communication passage branched from a downstream portion of the PCV valve in the blow-by gas passage. The blow-by gas device for a supercharged engine according to claim 9,
The supercharger main body has a sealing material that closes between the bearing portion and the rotor chamber,
Each of the suction side space portion and the discharge side space portion is a blow-by gas device for a supercharged engine, which is an annular space formed around the rotation shaft adjacent to the sealing material. The blow-by gas device for a supercharged engine according to claim 10,
The suction side space is a blow-by gas device for a supercharged engine, which is formed by an annular step provided in the supercharger main body and the sealing material. The blow-by gas device for a supercharged engine according to claim 10 or 11,
The discharge-side space portion is a blow-by gas device for a supercharged engine, which is formed between the sealing material and a sealing material arranged to face the sealing material. The blow-by gas device for a supercharged engine according to claim 10,
The blowby gas is discharged through an oil separator chamber provided in the engine body,
The blow-by gas device for an engine with a supercharger, wherein the first communication passage has a flow rate suppressing portion that communicates with the oil separator chamber and suppresses an inflow amount of the blow-by gas into the suction side space portion. . The blow-by gas device for a supercharged engine according to claim 13,
The blow-by gas device for a supercharged engine, wherein the first communication path further includes a back-flow suppressing unit that suppresses the back-flow of the blow-by gas to the oil separator chamber.

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