JP5978929B2 - Blow-by gas processing equipment - Google Patents

Description

  The present invention relates to a blow-by gas processing apparatus provided in an internal combustion engine in which a compressor for a supercharger is provided in an intake passage.

  2. Description of the Related Art A blow-by gas processing device that discharges and processes fuel gas (so-called blow-by gas) leaking from a combustion chamber of an internal combustion engine into a crankcase into the intake passage from the crankcase is put into practical use. In addition, when the above apparatus is applied to an internal combustion engine in which the compressor of the supercharger is provided in the intake passage, a communication passage that connects the portion in the intake passage downstream of the compressor in the intake flow direction and the inside of the crankcase is provided. Has been proposed (see Patent Document 1).

JP 2010-20984 A

  In the apparatus described in Patent Document 1, since a part of the intake air (air) in the intake passage flows into the crankcase through the communication passage, the ventilation in the crankcase and the blow-by gas processing are efficient. It is often done.

  On the other hand, when the operation state of the internal combustion engine becomes an operation state in which supercharging by the supercharger is performed, a large amount of air flows from the intake passage into the crankcase through the communication passage. As a result, the pressure in the crankcase is increased, and therefore the reliability of the internal combustion engine is reduced, for example, causing a decrease in the reliability of the seal member for preventing gas outflow from the inside of the engine or gas intrusion into the engine. There is a risk of lowering.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a blow-by gas processing apparatus capable of achieving both improvement in processing performance of blow-by gas and suppression of reduction in reliability of the internal combustion engine. There is.

  A blow-by gas processing apparatus for achieving the above object is applied to an internal combustion engine in which a compressor of a supercharger is provided in an intake passage, and discharges blow-by gas in a crankcase of the internal combustion engine to the intake passage. In the blow-by gas processing device to be processed, a communication passage that communicates a portion of the intake passage that is downstream of the compressor in the intake flow direction with the inside of the crankcase, and a portion of the intake passage that is downstream of the compressor in the intake flow direction. A shut-off valve that shuts off communication between the intake passage and the crankcase by the communication passage when the internal pressure is higher than the internal pressure of the crankcase and the difference between the internal pressures is equal to or greater than a predetermined pressure;

  In the above apparatus, when the internal pressure of the portion in the intake passage downstream of the compressor in the intake air flow direction (hereinafter simply referred to as downstream) is higher than the internal pressure of the crankcase and the difference between the internal pressures is less than a predetermined pressure, There is a low possibility that intake air (air) is excessively supplied from the intake passage into the crankcase due to the influence of supercharging by the machine. In the above apparatus, the intake passage and the crankcase are communicated with each other through the communication passage at this time, so that air can flow into the crankcase from the intake passage and ventilation in the crankcase is preferable. Therefore, it is possible to improve the processing performance of blow-by gas.

  On the other hand, when the internal pressure in the portion downstream of the compressor in the intake passage is higher than the internal pressure of the crankcase and the difference between the internal pressures is equal to or greater than a predetermined pressure, air is excessively supplied from the intake passage into the crankcase. It can be said that there is a high possibility of becoming a situation. In the above apparatus, since the communication between the intake passage through the communication passage and the inside of the crankcase is blocked by the shut-off valve at this time, even if the internal pressure of the intake passage is increased by supercharging by the supercharger Further, it is possible to suppress an excessive flow of air into the crankcase through the communication path. Therefore, an excessive increase in the internal pressure of the crankcase can be suppressed, and a decrease in the reliability of the internal combustion engine can be suppressed.

  In the blow-by gas processing apparatus, the intake passage extends in a curved shape in which a lower side in the vertical direction protrudes downstream from the compressor in the intake flow direction, and the communication passage extends in a curved shape of the intake passage. It is desirable to be connected to the lowest position in the vertical direction of the formed portion.

  In an internal combustion engine in which a compressor is provided in an intake passage, oil for lubricating the compressor may leak into the intake passage, and the oil may accumulate in a portion of the intake passage downstream of the compressor. In the above apparatus, oil is accumulated in a portion extending in a curved shape in which the lower side in the vertical direction is convex on the downstream side of the compressor in the intake passage. In view of this point, in the above apparatus, the communication path is connected to the lowest position in the vertical direction of the same part. Therefore, the oil accumulated in the above portion can be allowed to flow into the crankcase together with the air through this communication path. Thus, according to the above apparatus, the oil accumulated in the intake passage can be caused to flow into the crankcase.

  The shut-off valve is opened when the internal pressure of the portion of the intake passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase and the difference in internal pressure is less than a predetermined pressure, Adopting a mechanical check valve that closes when the internal pressure in the portion of the intake passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase and the difference between the internal pressures is greater than or equal to a predetermined pressure. Can do.

  According to such a device, excessive inflow of air into the crankcase can be automatically suppressed through the operation of the mechanical check valve. Therefore, the device can have a simple structure as compared with a device that employs an electric valve such as an electromagnetic valve as the shutoff valve.

  As the shutoff valve, when the internal pressure of the portion in the intake passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase, the opening degree decreases as the difference in the internal pressure increases. Can be adopted.

  According to the above apparatus, the internal pressure of the portion of the intake passage downstream from the compressor is higher than the internal pressure of the crankcase, and the difference between the internal pressures is large, so the air flows from the intake passage into the crankcase through the communication passage. As the amount of air tends to increase, the opening degree of the shutoff valve can be reduced. For this reason, the amount of air flowing into the crankcase from the intake passage via the communication passage can be adjusted to an appropriate amount in accordance with the difference in the internal pressure.

  In the blow-by gas processing apparatus, a throttle valve for variably setting a passage cross-sectional area of the intake passage is provided in a portion of the intake passage downstream of the compressor in the intake flow direction, and the intake flow direction from the throttle valve in the intake passage is provided. A connection passage that communicates the downstream portion and the inside of the crankcase can be provided, and the communication passage can be connected to a portion of the intake passage upstream of the throttle valve in the intake flow direction.

  According to the above apparatus, the gas including the blow-by gas in the crankcase is supplied to the intake passage through the connection passage using the pressure difference between the inside of the crankcase and the portion of the intake passage downstream of the throttle valve. Can be discharged.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the schematic structure about one Embodiment of a blow-by gas processing apparatus. The graph which shows the relationship between the difference of an internal pressure, and the air flow rate in a 2nd introductory passage. Schematic which shows an example of the operation | movement aspect of the blowby gas processing apparatus at the time of non-supercharging. Sectional drawing which expands and shows the cross-section of the 2nd introduction channel | path and its periphery. Schematic which shows an example of the operation | movement aspect of the blowby gas processing apparatus at the time of high supercharging.

Hereinafter, an embodiment of the blow-by gas processing apparatus will be described.
FIG. 1 shows a schematic configuration of a blow-by gas processing apparatus of the present embodiment and an internal combustion engine to which the apparatus is applied.

  As shown in FIG. 1, the internal combustion engine 10 includes a cylinder block 11. A cylinder head 12 is provided on the upper part of the cylinder block 11, and a head cover 13 is mounted on the upper part of the cylinder head 12. A crankcase 14 is formed at the lower part of the cylinder block 11, and an oil pan 15 is attached to the lower part of the crankcase 14. The oil pan 15 stores lubricating oil.

  A cylinder 16 is formed inside the cylinder block 11, and a piston 17 is disposed in the cylinder 16 so as to be capable of reciprocating. A combustion chamber 18 is defined in the internal combustion engine 10 by an inner peripheral wall of the cylinder 16, a top surface of the piston 17, and a lower surface of the cylinder head 12.

  The internal combustion engine 10 is provided with an exhaust-driven supercharger 30. The supercharger 30 includes a turbine 31 provided in the exhaust passage 20 of the internal combustion engine 10 and a compressor 32 provided in the intake passage 19 of the internal combustion engine 10. A turbine wheel 31 </ b> A inside the turbine 31 and a compressor impeller 32 </ b> A inside the compressor 32 are connected via a shaft 33 so as to be integrally rotatable.

  When a large amount of exhaust gas is blown to the turbine wheel 31A during the operation of the internal combustion engine 10, the turbine wheel 31A rotates together with the compressor impeller 32A, and thereby the intake air flowing through the intake passage 19 is pumped to the combustion chamber of the internal combustion engine 10. 18 is forcibly sent.

  In the intake passage 19 of the internal combustion engine 10, in order from the upstream side in the intake flow direction (hereinafter simply referred to as “upstream side”), the air cleaner 21 for filtering the intake air, the compressor 32, and the heat exchange with the atmosphere reduce the temperature of the intake air. An intercooler 22 and a throttle valve 23 for variably setting the passage sectional area of the intake passage 19 are provided.

  In the internal combustion engine 10, the combustion gas leaked from the combustion chamber 18 into the crankcase 14 through the gap between the sliding surfaces of the cylinder 16 and the piston 17 (specifically, the piston ring), that is, blow-by gas is recirculated into the intake air. A blow-by gas processing device is provided for processing. The blow-by gas processing apparatus includes two passages (a first breather passage and a second breather passage) as passages for discharging blow-by gas from the inside of the crankcase 14 to the intake passage 19.

  The first breather passage is constituted by the first passage 41, the second passage 42, the third passage 43, and the like. In the present embodiment, the first breather passage functions as a connection passage that communicates a portion of the intake passage downstream of the throttle valve in the intake flow direction (hereinafter simply referred to as downstream) and the inside of the crankcase.

  The first passage 41 is formed in the cylinder block 11 in an extending manner in which one end portion opens in the crankcase 14 and the other end portion opens in the connection surface with the cylinder head 12. . In the middle of the first passage 41, a first oil separator 44 for separating the gas passing through the inside and the oil mist is provided.

  The second passage 42 is formed in the cylinder head 12 in an extending manner in which one end portion opens at a position communicating with the first passage 41 and the other end portion opens inside the head cover 13. Yes. An end of the second passage 42 on the head cover 13 side is connected to a volume chamber 45 attached to the inside of the head cover 13.

  The third passage 43 extends in such a shape that one end is connected to the volume chamber 45 via the PCV valve 46 and the other end is connected to a portion of the intake passage 19 downstream of the throttle valve 23. It is installed. The PCV valve 46 is a differential pressure operating valve, and the opening degree of the PCV valve 46 is smaller as the pressure on the crankcase 14 side (specifically, the volume chamber 45 side) is higher than the pressure on the intake passage 19 side. When the opening is changed and the pressure on the volume chamber 45 side is equal to or lower than the pressure on the intake passage 19 side, the PCV valve 46 is closed. The PCV valve 46 prohibits the introduction of intake air from the intake passage 19 through the first breather passage into the crankcase 14 and discharge of gas including blow-by gas from the crankcase 14 to the intake passage 19 is allowed. The

The second breather passage is constituted by a drive gas passage 47, an ejector 48, a gas suction passage 49, and the like.
The drive gas passage 47 extends in a shape that communicates the upstream portion and the downstream portion of the compressor 32 in the intake passage 19 so as to bypass the compressor 32.

  The ejector 48 is disposed inside the head cover 13 and is provided in the middle of the drive gas passage 47. The ejector 48 has a structure in which intake air (air) supplied through the drive gas passage 47 passes therethrough. The ejector 48 is communicated with the inside of the cylinder head 12 via a second oil separator 50 for separating the gas passing through the inside and the oil mist. The ejector 48 draws in the gas in the cylinder head 12 through the second oil separator 50 using the force of intake air supplied through the driving gas passage 47 and flows through the inside, and drives the gas together with air. It is sent to the intake passage 19 through the gas passage 47. In the present embodiment, the ejector 48, the second oil separator 50, and the volume chamber 45 are integrally formed and disposed inside the head cover 13.

  Inside the cylinder block 11, a gas passage 51 extending in a shape that allows communication between the crankcase 14 and the cylinder head 12 is formed. In the present embodiment, the gas can be circulated between the inside of the cylinder head 12 and the inside of the crankcase 14 through the gas passage 51.

  Further, the blow-by gas processing apparatus of the present embodiment includes two passages (a first introduction passage 52 and a second introduction passage 53) as passages for introducing air from the intake passage 19 into the crankcase 14. .

  The first introduction passage 52 has one end connected to a portion upstream of the compressor 32 in the intake passage 19 and a portion downstream from the air cleaner 21, and the other end connected to the third oil separator 54. It is extended in the shape connected to the inside of the cylinder head 12 via. The third oil separator 54 is for separating the gas passing through the inside and the oil mist, and is disposed inside the head cover 13.

  The second introduction passage 53 is connected at one end to a portion upstream of the throttle valve 23 in the intake passage 19 and to a portion downstream of the intercooler 22 via a mechanical check valve 55. The other end extends in a shape that is directly connected to the crankcase 14. In the present embodiment, a portion of the intake passage 19 between the throttle valve 23 and the intercooler 22 is extended in a curved shape in which the lower side in the vertical direction (vertical direction in the drawing) is convex. The connection position of the second introduction passage 53 to the intake passage 19 is set to the lowest position in the vertical direction of the portion extending in the curved shape. In the present embodiment, the check valve 55 functions as a shutoff valve, and the second introduction passage 53 functions as a communication passage that communicates a portion of the intake passage downstream of the compressor and the inside of the crankcase.

As the check valve 55, there is provided a differential pressure operating valve whose opening degree changes in accordance with the pressure difference between the crankcase 14 side and the intake passage 19 side.
FIG. 2 shows the relationship between such a pressure difference and the air flow rate in the second introduction passage 53. In the following description, the internal pressure of the crankcase 14 is “P1”, and the internal pressure (throttle upstream pressure) of the portion of the intake passage 19 that is downstream of the intercooler 22 and upstream of the throttle valve 23 is “P2”. The difference between the internal pressure P1 of the crankcase 14 and the internal pressure of the intake passage 19 is defined as “ΔP (= P2−P1)”.

As shown in FIG. 2, in the present embodiment, the operating characteristics of the check valve 55 are set so as to satisfy all of the following [Condition A] to [Condition C].
[Condition A] When the difference ΔP in internal pressure is 0 or less (ΔP ≦ 0), the check valve 55 is closed.

When this [Condition A] is satisfied, although the internal pressure P1 of the crankcase 14 is higher than the throttle upstream pressure P2, the check valve 55 is closed at this time. Inflow of gas including blow-by gas from the crankcase 14 into the intake passage 19 is prohibited.
[Condition B] When the internal pressure difference ΔP is greater than “0” and less than the predetermined pressure JP (0 <ΔP <JP), the check valve 55 is opened. The opening of the check valve 55 at this time decreases as the internal pressure difference ΔP increases.

When this [Condition B] is satisfied, the check valve 55 is opened assuming that the throttle upstream pressure P2 is higher than the internal pressure P1 of the crankcase 14 and the difference ΔP between the internal pressures is small. Inflow of gas from the intake passage 19 through the second introduction passage 53 into the crankcase 14 is allowed.
[Condition C] When the internal pressure difference ΔP is equal to or greater than the predetermined pressure JP (ΔP ≧ JP), the check valve 55 is closed.

  When this [Condition C] is satisfied, although the throttle upstream pressure P2 is higher than the internal pressure P1 of the crankcase 14, it is assumed that the difference ΔP between the internal pressures is relatively large and the check valve 55 is The valve is closed, and the inflow of gas from the intake passage 19 through the second introduction passage 53 into the crankcase 14 is prohibited.

(Function)
Hereinafter, the operation of the blow-by gas processing apparatus will be described.
In the blow-by gas processing apparatus according to the present embodiment, when the gas including the blow-by gas in the crankcase 14 is discharged to the intake passage 19, the operating state of the supercharger 30 is in a non-supercharged state (during non-supercharging). And when it is in a low supercharging state (at the time of low supercharging) and when it is in a high supercharging state (at the time of high supercharging).

  Here, first, the operation of the blow-by gas processing apparatus during non-supercharging will be described with reference to FIG. In FIG. 3, black arrows indicate the flow of blow-by gas during non-supercharging, and white arrows indicate the flow of air during non-supercharging.

  At the time of non-supercharging, since the passage cross-sectional area of the intake passage 19 is reduced by the throttle valve 23, the internal pressure (throttle downstream pressure) of the portion of the intake passage 19 downstream from the throttle valve 23 is reduced. The pressure is lower than the internal pressure (throttle upstream pressure) of the portion upstream of the throttle valve 23 and downstream of the compressor 32.

  As shown in FIG. 3, in this embodiment, the PCV valve 46 is opened by this pressure difference, and the gas including the blow-by gas in the crankcase 14 flows into the first breather passage (the first passage 41, the second oil separator). 44, the second passage 42, and the third passage 43) are sucked into the portion of the intake passage 19 downstream of the throttle valve 23 and discharged. Further, at this time, since [Condition B] is satisfied and the check valve 55 is opened, a part of the intake air upstream of the throttle valve 23 in the intake passage 19 is cranked via the second introduction passage 53. It is introduced into the case 14. Further, at this time, the internal pressure of the crankcase 14 is lower than the internal pressure of the portion of the intake passage 19 upstream of the compressor 32 and downstream of the air cleaner 21. Part of the intake air is introduced into the crankcase 14 through the first introduction passage 52, the third oil separator 54, and the gas passage 51.

  On the other hand, at the time of low supercharging, although the throttle upstream pressure is increased by supercharging by the supercharger 30, the throttle downstream pressure is maintained lower than the throttle upstream pressure. Therefore, due to this pressure difference, the gas containing the blow-by gas in the crankcase 14 is discharged to the downstream portion of the intake passage 19 from the throttle valve 23 through the first breather passage, and from the throttle valve 23 in the intake passage 19. A part of the intake air in the upstream portion is introduced into the crankcase 14 through the second introduction passage 53.

  Further, at this time, the air pressure into the crankcase 14 through the second introduction passage 53 increases the internal pressure of the crankcase 14, and the internal pressure is a portion of the intake passage 19 upstream of the compressor 32 and It becomes higher than the internal pressure in the downstream portion of the air cleaner 21. Therefore, due to this pressure difference, the gas in the crankcase 14 passes through the gas passage 51, the third oil separator 54, and the first introduction passage 52 in this order and is discharged to the intake passage 19. Thus, at the time of low supercharging, unlike the case of non-supercharging (see FIG. 3), the first introduction passage 52 functions as a passage for discharging the gas in the crankcase 14 to the intake passage 19.

  In the apparatus of the present embodiment, when the throttle upstream pressure is higher than the internal pressure of the crankcase 14 and the difference between the internal pressures is less than the predetermined pressure JP, the inside of the intake passage 19 is caused by the influence of supercharging by the supercharger 30 or the like. The possibility that the intake air is excessively supplied into the crankcase 14 is low. In this embodiment, the check valve 55 is opened at this time, and the intake passage 19 and the crankcase 14 are communicated with each other via the second introduction passage 53. As a result, air is supplied from the intake passage 19 into the crankcase 14 and ventilation in the crankcase 14 is suitably performed, so that the processing performance of blow-by gas can be improved.

  In the apparatus of the present embodiment, when the throttle upstream pressure is higher than the internal pressure of the crankcase 14, the larger the difference between the internal pressures, the more the flow from the intake passage 19 into the crankcase 14 through the second introduction passage 53. The amount of air to be increased tends to increase.

  In the present embodiment, when the throttle upstream pressure is higher than the internal pressure of the crankcase 14 and the difference between the internal pressures is less than the predetermined pressure JP, the opening degree decreases as the internal pressure difference increases. A check valve 55 is provided in the second introduction passage 53 (see FIG. 2).

  Therefore, since the difference in internal pressure is large, the opening amount of the check valve 55 becomes smaller as the amount of air that flows into the crankcase 14 from the intake passage 19 via the second introduction passage 53 tends to increase. As a result, the amount of air flowing into the crankcase 14 from the intake passage 19 through the second introduction passage 53 is suppressed to an excessive amount, and an appropriate amount is obtained in accordance with the difference in the internal pressure. Can be adjusted to.

  In this embodiment, since the compressor 32 is provided in the intake passage 19, the lubricating oil of the compressor 32 leaks into the intake passage 19, and the downstream side of the compressor 32 in the intake passage 19. Oil may accumulate in the part. As shown in FIG. 4, in the apparatus of the present embodiment, the portion between the throttle valve 23 and the intercooler 22 in the intake passage 19 extends in a curved shape in which the lower side in the vertical direction is convex. Oil accumulates in the portion of the intake passage 19 that extends in the curved shape. In view of this point, in the apparatus of the present embodiment, the second introduction passage 53 is connected to the lowest position in the vertical direction of the portion of the intake passage 19 extended in the curved shape. Therefore, the oil accumulated in the portion can be returned to the crankcase 14 through the second introduction passage 53 together with the intake air. According to the present embodiment, the oil accumulated in the intake passage 19 in this way can be returned to the crankcase 14.

  Next, the operation of the blow-by gas processing apparatus during high supercharging will be described with reference to FIG. In FIG. 5, black arrows indicate the flow of blow-by gas at the time of high supercharging, and white arrows indicate the flow of air at the time of high supercharging.

  As shown in FIG. 5, at the time of high supercharging, a large pressure difference is generated between the upstream portion and the downstream portion of the compressor 32 in the intake passage 19, so that air flows in the drive gas passage 47. As a result, the ejector 48 is activated. The ejector 48 operates such that the gas in the second oil separator 50 is sucked into the inside and discharged together with the air by sending it to the intake passage 19 through the driving gas passage 47. As a result, the gas including the blow-by gas in the crankcase 14 is discharged into the intake passage 19 through a route such as the gas passage 51, the cylinder head 12, the second oil separator 50, and the drive gas passage 47. In the present embodiment, the ejector 48 may operate even during low supercharging.

  Further, at the time of high supercharging, since the amount of blow-by gas leaked from the combustion chamber 18 into the crankcase 14 increases and the internal pressure of the crankcase 14 increases, the internal pressure is higher than that of the compressor 32 in the intake passage 19. It becomes higher than the pressure on the upstream side. Therefore, due to the pressure difference, the gas including the blow-by gas in the crankcase 14 is discharged into the intake passage 19 through the passages such as the gas passage 51, the cylinder head 12, the third oil separator 54, and the first introduction passage 52. It becomes like this.

  Further, at the time of high supercharging, the throttle upstream pressure becomes very high due to supercharging by the supercharger 30, so that the throttle upstream pressure becomes higher than the internal pressure of the crankcase 14, and the pressure difference between them becomes large. Therefore, it can be said that there is a high possibility that air will excessively flow into the crankcase 14 from the intake passage 19 at this time.

  In this regard, in the apparatus of the present embodiment, when the throttle upstream pressure is higher than the internal pressure of the crankcase 14 and the difference between the pressures (the difference ΔP) is equal to or greater than the predetermined pressure JP, the check valve 55 is closed. The communication between the intake passage 19 and the crankcase 14 by the second introduction passage 53 is blocked. Therefore, even when the throttle upstream pressure increases due to supercharging by the supercharger 30, it is possible to prevent excessive air from flowing into the crankcase 14 through the second introduction passage 53. Therefore, an excessive increase in the internal pressure of the crankcase 14 can be suppressed, and a decrease in reliability of the internal combustion engine 10 can be suppressed.

  In the present embodiment, based on the results of various experiments and simulations, the internal pressure difference ΔP that suppresses an excessive increase in the internal pressure of the crankcase 14 is obtained in advance, and the internal pressure thus obtained is determined. The largest value among the differences ΔP is set as the predetermined pressure JP.

  In the apparatus of the present embodiment, a mechanical type is adopted as the check valve 55, so that excessive inflow of air into the crankcase 14 can be automatically suppressed through the operation of the check valve 55. Therefore, compared with a device that employs an electric valve such as an electromagnetic valve as the check valve 55, the device can have a simple structure.

As described above, according to the present embodiment, the following effects can be obtained.
(1) When the throttle upstream pressure is higher than the internal pressure of the crankcase 14 and the difference ΔP between the internal pressures is less than the predetermined pressure JP, the intake passage 19 and the crankcase 14 communicate with each other via the second introduction passage 53. Is done. Therefore, it becomes possible to allow intake air to flow into the crankcase 14 from the intake passage 19 so that the inside of the crankcase 14 can be favorably ventilated, and the blow-by gas processing performance can be improved. it can. In addition, when the throttle upstream pressure is higher than the internal pressure of the crankcase 14 and the difference ΔP between the pressures is equal to or greater than the predetermined pressure JP, the check valve 55 is closed and the intake passage 19 and the crank through the second introduction passage 53 are closed. Communication with the inside of the case 14 is blocked. Therefore, an excessive increase in the internal pressure of the crankcase 14 can be suppressed, and a decrease in reliability of the internal combustion engine 10 can be suppressed.

  (2) The portion of the intake passage 19 between the throttle valve 23 and the intercooler 22 is extended in a curved shape in which the lower side in the vertical direction is convex, and the second introduction passage 53 is extended in the curved shape. Connected to the lowest position in the vertical direction. Therefore, the oil accumulated in the intake passage 19 can be returned to the crankcase 14.

  (3) When the throttle upstream pressure is higher than the internal pressure of the crankcase 14, the valve is opened when the internal pressure difference ΔP is less than the predetermined pressure JP, and closed when the internal pressure difference ΔP is equal to or higher than the predetermined pressure JP. A mechanical check valve 55 is provided. Therefore, compared with a device that employs an electric valve such as an electromagnetic valve as the check valve 55, the device can have a simple structure.

  (4) As the check valve 55, when the throttle upstream pressure P2 is higher than the internal pressure P1 of the crankcase 14 and the internal pressure difference ΔP is less than the predetermined pressure JP, the internal pressure difference ΔP increases. A device with a small opening is provided. Therefore, the amount of intake air flowing from the intake passage 19 into the crankcase 14 via the second introduction passage 53 can be adjusted to an appropriate amount in accordance with the internal pressure difference ΔP.

  (5) A second introduction passage 53 that communicates the portion of the intake passage 19 downstream of the throttle valve 23 and the inside of the crankcase 14 is provided. Therefore, using the pressure difference between the inside of the crankcase 14 and the portion of the intake passage 19 downstream of the throttle valve 23, the gas containing the blow-by gas in the crankcase 14 is discharged to the intake passage 19 and the combustion chamber 18 is discharged. The blow-by gas can be processed by this.

The above embodiment may be modified as follows.
The end of the second introduction passage 53 on the internal combustion engine 10 side is not directly connected to the crankcase 14, but a passage communicating with the crankcase 14 is formed inside the cylinder block 11 and the second passage is formed in the second passage. The introduction passage 53 may be connected. In short, if the second introduction passage 53 communicates with the inside of the crankcase 14, the connection position of the end portion of the second introduction passage 53 on the internal combustion engine 10 side can be arbitrarily changed.

  In place of the mechanical check valve 55, an electric valve such as an electromagnetically driven valve and an electronic control device including a microcomputer may be provided. In such a device, the operation control of the valve may be executed by an electronic control device.

Instead of the check valve 55, a check valve of a type that can be switched between a closed state (opening = 0) and a closed state (constant opening) according to the internal pressure difference ΔP may be provided. .
The second introduction passage 53 is not limited to being connected to the lowest point in the curved portion of the intake passage 19, but may be connected to the vicinity of the lowest point. By connecting the second introduction passage 53 to a position where the oil flows down in the intake passage 19, the oil can be discharged into the crankcase 14 through the second introduction passage 53.

  The second introduction passage 53 is not limited to being connected to the lowest point or the vicinity of the lowest point in the curved portion of the intake passage 19, but if it is a portion between the throttle valve 23 and the compressor 32 in the intake passage 19, Any part may be connected.

The second breather passage (specifically, the driving gas passage 47, the ejector 48, the gas suction passage 49, and the second oil separator 50) may be omitted.
The blow-by gas processing apparatus of the above embodiment is not limited to the internal combustion engine provided with the exhaust-driven supercharger 30, but is also provided in the internal combustion engine provided with the engine-driven supercharger driven by the engine output shaft. Can also be applied.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Cylinder block, 12 ... Cylinder head, 13 ... Head cover, 14 ... Crankcase, 15 ... Oil pan, 16 ... Cylinder, 17 ... Piston, 18 ... Combustion chamber, 19 ... Intake passage, 20 ... Exhaust Passage, 21 ... Air cleaner, 22 ... Intercooler, 23 ... Throttle valve, 30 ... Supercharger, 31 ... Turbine, 31A ... Turbine wheel, 32 ... Compressor, 32A ... Compressor impeller, 33 ... Shaft, 41 ... First passage, 42 ... second passage, 43 ... third passage, 44 ... first oil separator, 45 ... volume chamber, 46 ... PCV valve, 47 ... drive gas passage, 48 ... ejector, 49 ... gas suction passage, 50 ... second oil Separator 51 ... Gas passage 52 ... First introduction passage 53 ... Second introduction passage 54 ... Third oil separator 55 ... H Click valve.

Claims (5)

In a blow-by gas processing apparatus that applies a compressor of a supercharger to an internal combustion engine provided in an intake passage, and discharges and processes blow-by gas in a crankcase of the internal combustion engine to the intake passage.
A communication passage that communicates a portion of the intake passage downstream of the compressor in the intake flow direction with the inside of the crankcase, and an internal pressure of a portion of the intake passage downstream of the compressor in the intake flow direction is the interior of the crankcase. A blow-by gas processing device comprising a shut-off valve that shuts off communication between the intake passage and the inside of the crankcase when the pressure is higher than the pressure and the difference between the internal pressures is greater than or equal to a predetermined pressure. The blow-by gas processing apparatus according to claim 1,
The intake passage extends in a curved shape in which a lower side in the vertical direction is convex on the downstream side in the intake flow direction from the compressor,
The blow-by gas processing apparatus is characterized in that the communication passage is connected to a lowest position in a vertical direction of a portion extending in a curved shape of the intake passage. In the blowby gas processing apparatus according to claim 1 or 2,
The shut-off valve opens when the internal pressure of the portion of the intake passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase and the difference between the internal pressures is less than a predetermined pressure, It is a mechanical check valve that closes when the internal pressure in the portion of the passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase and the difference between the internal pressures is equal to or greater than a predetermined pressure. Blow-by gas processing equipment. In the blowby gas processing apparatus according to any one of claims 1 to 3,
When the internal pressure of the portion of the intake passage downstream of the compressor in the intake flow direction is higher than the internal pressure of the crankcase, the opening of the shut-off valve decreases as the difference in the internal pressure increases. A blow-by gas processing apparatus. In the blowby gas processing apparatus according to any one of claims 1 to 4,
The apparatus is provided with a throttle valve for variably setting a passage cross-sectional area of the intake passage in a portion of the intake passage downstream of the compressor in the intake flow direction, and downstream of the throttle valve in the intake passage in the intake flow direction. A connecting passage communicating the portion of the crankcase and the inside of the crankcase,
The blow-by gas processing apparatus, wherein the communication passage is connected to a portion of the intake passage upstream of the throttle valve in the intake flow direction.