JP2008095528A - Internal combustion engine having blow-by gas processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine having a blow-by gas processing apparatus, capable of appropriately discharging blow-by gas in the engine. <P>SOLUTION: The internal combustion engine 10 includes a first breather passage 41, a second breather passage 42, an introduction passage 43, and a filter 28B. The first breather passage 41 and the second breather passage 42 are configured to communicate an intake passage 20 with inside of a crankcase 14. The introduction passage 43 is configured to communicate an interior of a head cover 13 with a portion of the intake passage 20 (inside of an air cleaner 28) upstream of the breather passages 41, 42. The filter 28B filters intake air passing through the intake passage 20. The filter 28B is arranged between a portion of the intake passage 20 communicating with the introduction passage 43 and portions of the intake passage 20 respectively communicating with the breather passages 41, 42. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine equipped with a blow-by gas processing device that recirculates blow-by gas in an engine during intake.

  As an apparatus applied to an internal combustion engine such as a vehicle, for example, as described in Patent Document 1, ventilation of combustion gas (blow-by gas) leaking into a crankcase from a gap between a cylinder and a piston is performed and the ventilation is performed. A blow-by gas processing apparatus is known in which the blow-by gas returned to the intake air is processed. In such an internal combustion engine with a blow-by gas processing device, the blow-by gas recirculated into the intake air is recombusted in the combustion chamber, so that the amount of hydrocarbon (HC) discharged into the atmosphere can be reduced. Further, the deterioration of oil due to blow-by gas can be suppressed by ventilation inside the engine.

  Generally, the blow-by gas processing apparatus includes an introduction passage, a breather passage, and a PCV (Positive Crankcase Ventilation) valve. The introduction passage is a passage that communicates the inside of the engine (for example, the inside of the head cover or the inside of the crankcase) with the upstream side in the intake flow direction from the throttle valve in the intake passage, and introduces the intake air (outside air) in the intake passage into the engine. Used to do. The breather passage is a passage that communicates the inside of the engine and the downstream side in the intake flow direction from the throttle valve in the intake passage, and is used to send blow-by gas inside the engine into the intake passage. On the other hand, the PCV valve is a differential pressure operating valve that is disposed in the breather passage and whose opening degree is changed according to the differential pressure between the inside of the engine and the intake passage.

In such a blow-by gas processing device, the blow-by gas inside the engine is caused by a differential pressure between the inside of the engine, which has become relatively high pressure due to the introduction of outside air through the introduction passage, and the downstream side (intake negative pressure) in the intake passage. Aspirated and recirculated during inhalation. Further, the opening degree of the PCV valve is changed in accordance with such a differential pressure, whereby the flow rate of the blow-by gas recirculated into the intake air through the breather passage is autonomously adjusted.
JP 7-150923 A

  In a device that performs natural ventilation of blow-by gas using only the differential pressure between the upstream side and the downstream side of the throttle valve in the intake passage, for example, in the high load operation region of the internal combustion engine, the opening of the throttle valve becomes large and the above difference If the pressure does not increase too much, the blow-by gas inside the engine cannot be ventilated sufficiently. In addition, for example, an internal combustion engine that does not generate intake negative pressure, such as an internal combustion engine that is not provided with a throttle valve, cannot be originally applied with the blow-by gas processing device that uses the differential pressure.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine with a blow-by gas processing device that can suitably perform blow-by gas ventilation inside the engine.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
According to a first aspect of the present invention, there is provided a breather passage that communicates the intake passage with the interior of the engine, and an introduction passage that communicates a portion of the intake passage upstream of the breather passage with respect to the intake flow direction and the interior of the engine. The gist of the present invention is to include a filter that is provided in a portion of the intake passage between the communication portion of the introduction passage and the communication portion of the breather passage and filters the intake air passing through the intake passage.

  According to the above configuration, the pressure loss generated in the filter does not depend on the operating state of the internal combustion engine, and the intake passage downstream (hereinafter simply “downstream”) portion of the filter in the intake passage (hereinafter simply referred to as “downstream”). ) Can be made lower than the pressure at the upstream side (hereinafter simply referred to as “upstream side”) of the intake flow direction (the communication portion of the introduction passage). Therefore, due to this pressure difference, the introduction of outside air from the intake passage through the introduction passage to the inside of the engine and the discharge of blow-by gas from the inside of the engine to the intake passage through the breather passage can be stably performed. Gas ventilation can be suitably performed.

  According to a second aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the first aspect, the intake passage includes an air cleaner incorporating two filters arranged at intervals in the intake flow direction. The gist of the present invention is that the introduction passage communicates with a portion between the two filters in the air cleaner, and the breather passage communicates with a portion of the intake passage downstream of the two filters in the intake flow direction. And

  According to the above configuration, a pressure difference is generated between the communication portion of the breather passage and the communication portion of the introduction passage in the intake passage due to the pressure loss generated in the filter downstream of the two filters in the intake flow direction. be able to.

  According to a third aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the first or second aspect, the supercharger that performs supercharging by pumping the intake air flowing through the intake passage is the filter. The throttle valve is disposed further downstream in the intake flow direction, and a throttle valve that variably sets the cross-sectional area of the intake passage is disposed downstream in the intake flow direction from the supercharger. A first one-way discharge valve that allows only gas discharge from the inside of the engine to the intake passage is provided, and a portion of the intake passage that is downstream of the throttle valve in the intake flow direction communicates with the inside of the engine. A portion between the filter and the supercharger in the intake passage having a first breather passage and a second one-way exhaust valve that allows only gas discharge from the inside of the engine to the intake passage By comprising a second breather passage connecting the interior of the engine and its gist.

  According to the above configuration, when the supercharger is in the non-operating state (non-supercharging), the pressure difference generated between the upstream side and the downstream side of the filter and the negative pressure (intake air) generated on the downstream side of the throttle valve. Negative pressure), the pressure of the communication portion of the first breather passage in the intake passage can be made lower than the pressure of the communication portion of the introduction passage. And by this pressure difference, the blow-by gas inside the engine can be ventilated through the first breather passage and the introduction passage.

  On the other hand, when the supercharger is in an operating state (at the time of supercharging), the pressure difference in the upstream side and the downstream side of the filter and the negative pressure generated in the upstream side of the supercharger cause the above-described intake passage. The pressure of the communication portion of the second breather passage can be made lower than the pressure of the communication portion of the introduction passage. And by this pressure difference, the blow-by gas inside the engine can be ventilated through the second breather passage and the introduction passage.

Thus, according to the said structure, the blow-by gas inside an engine can be ventilated suitably irrespective of the presence or absence of supercharging.
According to a fourth aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the third aspect, the first breather passage and the second breather passage have the same communicating portion on the internal combustion engine side. The gist of that is.

  When the discharge mode of blow-by gas from the inside of the engine and the introduction mode of outside air into the engine are different between supercharged and non-supercharged, the engine The flow of blow-by gas and the flow of outside air in the interior will be greatly disturbed, for example, due to temporary stagnation. Therefore, the blow-by gas inside the engine cannot be efficiently replaced with outside air, and efficient ventilation of the blow-by gas inside the engine cannot be realized.

  In this regard, according to the above configuration, blow-by gas is discharged from the same portion inside the engine to the intake passage and outside air is introduced from the same portion into the engine regardless of whether the turbocharger is activated. In addition, the flow direction of the blowby gas and the flow direction of the outside air inside the engine can be made substantially constant without changing. Therefore, the blow-by gas inside the engine can be efficiently ventilated.

  According to a fifth aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the third or fourth aspect, when the pressure in the portion of the intake passage between the filter and the supercharger is lower than a predetermined pressure Further, the gist of the present invention is to provide a discharge restriction valve that reduces the cross-sectional area of the second breather passage as compared with the case where the pressure is equal to or higher than the predetermined pressure.

  According to the above configuration, when the pressure in the portion between the filter and the supercharger in the intake passage becomes low during supercharging, the internal pressure of the engine becomes excessively low due to this. It is possible to suppress the deterioration of the reliability of the internal combustion engine.

  A sixth aspect of the present invention is the internal combustion engine with a blow-by gas processing device according to any one of the third to fifth aspects, wherein the first one-way exhaust valve includes the engine inner side and the intake air. The gist of the present invention is that it is a differential pressure operating valve that is changed to a larger opening as the differential pressure from the passage side is smaller.

  During non-supercharging, the amount of blow-by gas generated increases as the throttle valve opening increases and the intake amount of the internal combustion engine increases. In the above configuration, the opening degree of the first one-way exhaust valve as the differential pressure operating valve becomes larger as the opening degree of the throttle valve is larger and the differential pressure is smaller, and a large amount of blow-by gas is discharged from the inside of the engine to the intake passage. Will come to be. Therefore, according to the above configuration, the amount of blow-by gas discharged from the engine at the time of non-supercharging can be accurately adjusted according to the state of blow-by gas generation.

As the second one-way discharge valve, a check valve can be employed as in the seventh aspect.
According to an eighth aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the first or second aspect, the throttle passage for variably setting the cross-sectional area of the intake passage is an intake flow from the filter. The gist is that the breather passage is communicated with a portion of the intake passage downstream of the throttle valve in the intake flow direction.

  According to the above configuration, when the opening of the throttle valve is small, the negative pressure (intake negative pressure) generated on the downstream side of the throttle valve reduces the pressure of the communicating portion of the breather passage in the intake passage, and the pressure and Since the difference between the intake passage and the communicating portion of the introduction passage becomes large, the blow-by gas inside the engine can be ventilated more efficiently.

  According to a ninth aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the eighth aspect, the breather passage allows only gas discharge from the inside of the engine to the intake passage and is provided on the inner side of the engine. The gist is that a control valve that is changed to a larger opening degree is provided as the difference between the pressure and the pressure on the intake passage side is smaller.

  In an internal combustion engine provided with a throttle valve, the amount of blow-by gas generated increases as the opening of the throttle valve increases and the amount of intake air increases. In the above configuration, as the throttle valve opening is larger and the differential pressure is smaller, the control valve opening is larger, and a large amount of blow-by gas is discharged from the engine into the intake passage. Therefore, according to the above configuration, it is possible to accurately adjust the amount of blow-by gas discharged from the engine according to the state of blow-by gas generation.

  According to a tenth aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the first or second aspect, the supercharger that performs supercharging by pumping the intake air flowing through the intake passage is the filter. It is arranged more downstream in the intake air flow direction, and the breather passage is communicated with a portion of the intake passage between the filter and the supercharger.

  According to the above configuration, in the internal combustion engine provided with the supercharger, the pressure of the communication portion of the breather passage in the intake passage is made lower than the pressure of the communication portion of the introduction passage regardless of the presence or absence of supercharging. The blow-by gas inside the engine can be ventilated.

  According to an eleventh aspect of the present invention, in the internal combustion engine with a blow-by gas processing device according to the tenth aspect, when a pressure in a portion of the intake passage between the filter and the supercharger is lower than a predetermined pressure, The gist of the invention is to provide a discharge restriction valve that reduces the cross-sectional area of the breather passage as compared with the case where the pressure is higher than the predetermined pressure.

  According to the above configuration, when the pressure in the portion between the filter and the supercharger in the intake passage becomes low during supercharging, the internal pressure of the engine becomes excessively low due to this. It is possible to suppress the deterioration of the reliability of the internal combustion engine.

Hereinafter, an embodiment in which an internal combustion engine with a blow-by gas processing apparatus according to the present invention is embodied will be described.
FIG. 1 shows a specific configuration of the internal combustion engine according to the present embodiment.

  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 oil for engine lubrication.

  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. An intake passage 20 is connected to the combustion chamber 18 via an intake valve 19, and an exhaust passage 22 is connected via an exhaust valve 21. A communication passage 23 is formed in the internal combustion engine 10 so as to communicate the inside of the head cover 13 with the crankcase 14.

  The internal combustion engine 10 is provided with an exhaust-driven supercharger 24. The supercharger 24 includes a turbine wheel 25 provided in the exhaust passage 22 of the internal combustion engine 10 and a compressor impeller 26 provided in the intake passage 20 of the internal combustion engine 10. The turbine wheel 25 and the compressor impeller 26 are connected via a shaft 27 so as to be integrally rotatable.

  When a large amount of exhaust gas is blown to the turbine wheel 25, the turbine wheel 25 also rotates together with the compressor impeller 26, whereby the intake air flowing through the intake passage 20 is pumped and the combustion chamber of the internal combustion engine 10 is compressed. 18 is forcibly sent. The supercharger 24 does not operate when the load on the internal combustion engine 10 is small and the exhaust amount is small (work amount≈ “0”), and operates when the load on the internal combustion engine 10 increases and the exhaust amount increases (work). Amount >> "0").

  In the intake passage 20 of the internal combustion engine 10, the temperature of the intake air is lowered through heat exchange with the air cleaner 28 that filters the intake air, the compressor impeller 26, and the atmosphere in order from the upstream side in the intake flow direction (hereinafter simply “upstream side”). An intercooler 29 and a throttle valve 30 as a throttle valve for variably setting the passage sectional area of the intake passage 20 are provided. The turbine wheel 25 is disposed in the exhaust passage 22 of the internal combustion engine 10. The internal combustion engine 10 is provided with a fuel injection valve (not shown). In the internal combustion engine 10, fuel is injected from the fuel injection valve and supplied into the combustion chamber 18.

  Further, 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, that is, blow-by gas is returned to the intake air for processing. A blow-by gas processing device is provided.

  This blow-by gas processing apparatus has two passages (a first breather passage 41 and a second breather passage 42) for discharging blow-by gas from the inside of the engine (specifically, inside the crankcase 14) to the intake passage 20. And an introduction passage 43 for introducing intake air (outside air) from the intake passage 20 into the engine (specifically, inside the head cover 13).

The first breather passage 41 is a passage that communicates a portion of the intake passage 20 downstream of the throttle valve 30 with the inside of the crankcase 14.
The end of the first breather passage 41 on the crankcase 14 side is connected to the crankcase 14 via a PCV valve 44. The PCV valve 44 is a differential pressure operating valve, and the opening degree of the PCV valve 44 is changed to a smaller opening degree as the pressure on the crankcase 14 side is higher than the pressure on the intake passage 20 side. The PCV valve 44 prohibits introduction of outside air from the intake passage 20 through the first breather passage 41 into the crankcase 14 and discharge of blow-by gas from the crankcase 14 to the intake passage 20 is allowed. . Further, the flow rate of blow-by gas discharged to the intake passage 20 through the first breather passage 41 by the PCV valve 44 depends on the difference between the pressure on the crankcase 14 side of the PCV valve 44 and the pressure on the intake passage 20 side. It is adjusted autonomously. In the present embodiment, the PCV valve 44 functions as a first one-way discharge valve.

  The crankcase 14 is provided with an oil separator 45 for separating blowby gas and oil mist, and the end portion of the first breather passage 41 on the crankcase 14 side is connected to the oil separator 45. Has been. That is, the first breather passage 41 communicates with the crankcase 14 via the oil separator 45.

  The second breather passage 42 is a passage communicating the portion between the air cleaner 28 and the supercharger 24 in the intake passage 20 and the inside of the crankcase 14. A check valve is provided in the middle of the second breather passage 42. 46 is provided. The check valve 46 prohibits the introduction of outside air from the intake passage 20 through the second breather passage 42 into the crankcase 14 and permits the discharge of blowby gas from the crankcase 14 into the intake passage 20. Is done. In the present embodiment, the check valve 46 functions as a second one-way discharge valve.

  The end of the second breather passage 42 on the crankcase 14 side is connected to the oil separator 45. That is, the first breather passage 41 and the second breather passage 42 are communicated with the same portion on the internal combustion engine 10 side.

  The introduction passage 43 is a passage that communicates a portion upstream of the communication portion of the second breather passage 42 in the intake passage 20 (specifically, the inside of the air cleaner 28) and the inside of the head cover 13.

  FIG. 2 shows the internal structure of the air cleaner 28. As shown in FIG. 2, two filters 28 </ b> A and 28 </ b> B each having a shape that partitions the inside of the air cleaner 28 into an upstream side and a downstream side are provided in the air cleaner 28 with an interval in the intake flow direction. . An end portion of the introduction passage 43 on the intake passage 20 side is communicated with a portion between the two filters 28 </ b> A and 28 </ b> B inside the air cleaner 28.

  On the other hand, the end of the introduction passage 43 on the head cover 13 (FIG. 1) side is connected to an oil separator 47 provided inside the head cover 13. That is, the introduction passage 43 communicates with the head cover 13 via the oil separator 47.

Hereinafter, the operation of the internal combustion engine 10 according to the present embodiment will be described.
The arrows in FIG. 1 indicate the outside air introduction path into the head cover 13 and the blow-by gas discharge path from the crankcase 14. In the drawing, a black arrow indicates when the supercharger 24 is in an inoperative state (specifically, when the pressure in the portion downstream from the throttle valve 30 is lower than the atmospheric pressure, The white arrows indicate the respective routes when the supercharger 24 is in an operating state (at the time of supercharging).

  In the internal combustion engine 10 according to the present embodiment, when intake air passes through the air cleaner 28, pressure loss occurs in the two filters 28A and 28B built in the air cleaner 28, respectively. Therefore, regardless of the operating state of the internal combustion engine 10, the pressure (air cleaner internal pressure P1) between the filters 28A and 28B inside the air cleaner 28 becomes lower than the atmospheric pressure, and further downstream of the two filters 28A and 28B. The pressure on the side portion (air cleaner downstream pressure P2) becomes lower than the air cleaner internal pressure P1 (atmospheric pressure> P1> P2).

  Further, during non-supercharging, a negative pressure (intake negative pressure) is generated in the portion of the intake passage 20 downstream of the throttle valve 30 due to the throttle effect of the throttle valve 30. P3) becomes lower than the air cleaner downstream pressure P2 (P2> P3).

  Therefore, at the time of non-supercharging, the pressure difference in the intake passage 20 is caused by the pressure difference generated between the upstream side and the downstream side of the filter 28B on the downstream side of the two filters and the negative pressure generated on the downstream side of the throttle valve 30. The pressure at the communicating portion of the first breather passage 41 (throttle downstream pressure P3) is lower than the pressure at the communicating portion of the introduction passage 43 in the air cleaner 28 (air cleaner internal pressure P1) (P1> P3). The blow-by gas inside the engine is ventilated through the first breather passage 41 and the introduction passage 43 based on this pressure difference.

  Specifically, the intake air flowing through the air cleaner 28 (specifically, the portion between the filters 28A and 28B) is introduced into the head cover 13 through the introduction passage 43. Due to the pressure difference (P4> P3) between the pressure inside the engine (the inside of the head cover 13 and the inside of the crankcase 14) (the inside pressure of the crankcase 14) and the throttle downstream pressure P3 (P4> P3). Through the breather passage 41, blow-by gas inside the engine is sucked (exhausted) into the intake passage 20 and recirculated into the intake air.

  Thus, during non-supercharging, outside air is introduced into the head cover 13 through the introduction passage 43, and blow-by gas is discharged to the intake passage 20 through the first breather passage 41 to ventilate the blow-by gas inside the engine. .

  Here, if the opening degree of the throttle valve 30 increases during non-supercharging, the intake negative pressure disappears. In this embodiment, even in such a case, the difference between the throttle downstream pressure P3 and the air cleaner internal pressure P1 is secured by the pressure difference generated between the upstream side and the downstream side of the filter 28B. Blowby gas ventilation can be performed.

  During non-supercharging, the amount of blow-by gas generated increases as the opening of the throttle valve 30 increases and the intake air amount of the internal combustion engine 10 increases. In this regard, in the present embodiment, the more the opening degree of the throttle valve 30 is larger and the difference between the air cleaner internal pressure P1 and the throttle downstream pressure P3 is smaller, in other words, the intake passage 20 side of the PCV valve 44 and the crankcase 14. The smaller the pressure difference from the engine side, the larger the opening of the PCV valve 44, and a larger amount of blow-by gas is discharged into the intake passage 20 from the inside of the engine. As a result, the amount of blow-by gas discharged from the inside of the engine is accurately adjusted according to the state of blow-by gas generation.

  On the other hand, at the time of supercharging, the throttle downstream pressure P3 becomes higher than the air cleaner internal pressure P1 due to a positive pressure (so-called supercharging pressure) generated on the downstream side of the supercharger 24 in accordance with intake pressure feeding by the supercharger 24. (P3> P1). Therefore, communication between the crankcase 14 and the intake passage 20 by the first breather passage 41 is blocked by the PCV valve 44, and discharge of blow-by gas through the first breather passage 41 is prohibited.

  However, at this time, the pressure (air cleaner downstream pressure P2) in the portion of the intake passage 20 between the air cleaner 28 and the supercharger 24 is lowered by the negative pressure generated on the upstream side of the supercharger 24. Therefore, at the time of supercharging, the intake passage is caused by the negative pressure generated on the upstream side of the supercharger 24 and the pressure difference generated between the upstream side and the downstream side of the filter 28B on the downstream side of the two filters described above. 20, the pressure at the communicating portion of the second breather passage 42 (air cleaner downstream pressure P2) becomes lower than the pressure at the communicating portion of the introduction passage 43 in the air cleaner 28 (air cleaner internal pressure P1) (P1> P2). The blow-by gas inside the engine is ventilated through the second breather passage 42 and the introduction passage 43 based on this pressure difference.

  Specifically, the intake air flowing through the air cleaner 28 (specifically, the portion between the filters 28A and 28B) is introduced into the head cover 13 through the introduction passage 43. Then, the blow-by gas inside the engine is passed through the second breather passage 42 due to the differential pressure (P4> P2) between the pressure inside the engine (engine internal pressure P4) and the air cleaner downstream pressure P2 which has become relatively high. Is sucked (discharged) into the intake passage 20 and recirculated into the intake air.

  In this way, during supercharging, outside air is introduced into the head cover 13 through the introduction passage 43 and blow-by gas is discharged to the intake passage 20 through the second breather passage 42 to ventilate the blow-by gas inside the engine.

  Here, when the work amount of the supercharger 24 is small during supercharging, the negative pressure generated on the upstream side of the supercharger 24 is small. In the present embodiment, even in such a case, the difference between the air cleaner downstream pressure P2 and the air cleaner internal pressure P1 is ensured by the pressure difference generated between the upstream side and the downstream side of the filter 28B. Ventilation of blowby gas can be suitably performed.

  According to the present embodiment, the pressure loss generated in the downstream filter 28B of the two filters built in the air cleaner 28 causes the air cleaner downstream pressure P2 to be the air cleaner internal pressure P1 regardless of the operating state of the internal combustion engine 10. Lower. Therefore, compared to a configuration in which the pressure difference does not occur due to this pressure difference, outside air is introduced into the head cover 13 from the intake passage 20 through the introduction passage 43 and through the first breather passage 41 or the second breather passage 42. Further, the blow-by gas discharge from the crankcase 14 to the intake passage 20 is performed in a stable state, and ventilation of the blow-by gas inside the engine is suitably executed.

  Moreover, according to the present embodiment, the blow-by gas is discharged from the crankcase 14 to the intake passage 20 and the outside air is introduced into the head cover 13 from the intake passage 20 regardless of whether it is non-supercharged or supercharged. be able to. Therefore, the blow-by gas inside the engine can be ventilated more efficiently than the configuration in which the discharge of blow-by gas and the introduction of outside air are stopped during non-supercharging or supercharging. Accordingly, it is possible to suitably suppress the amount of hydrocarbon (HC) discharged into the atmosphere, oil deterioration due to the mixing of fuel components in the blow-by gas, the amount of oil sludge accumulated based on the blow-by gas, and the like. It becomes like this.

  Here, even if the blow-by gas is discharged and the outside air is introduced both at the time of non-supercharging and at the time of supercharging, the manner of discharging the blow-by gas from the inside of the engine and the way of introducing the outside air into the engine are excessive. In the configuration that differs between the time of charging and the time of non-supercharging, the flow of blow-by gas and the flow of outside air inside the engine are temporarily increased each time the operating state and non-operating state of the turbocharger are switched. It will be disturbed. In the configuration in which the flow direction of the blow-by gas and the flow direction of the outside air in the communication passage connecting the intake passage and the inside of the engine are opposite in non-supercharging and supercharging, the blow-by gas in the communication passage The air is returned to the inside, or the outside air in the communication passage is returned to the intake passage. Therefore, none of these configurations can efficiently replace the blow-by gas inside the engine with the outside air, that is, it is impossible to realize efficient ventilation of the blow-by gas inside the engine.

  In this regard, in the present embodiment, the direction in which the blow-by gas flows in the first breather passage 41 and the second breather passage 42 is always constant, and the direction in which the outside air flows in the introduction passage 43 is always constant. It is. Therefore, when the operating state and the non-operating state of the supercharger 24 are switched, the blow-by gas in the first breather passage 41 or the blow-by gas in the second breather passage 42 flows backward, or in the introduction passage 43. There is no backflow of outside air.

  Further, regardless of whether the supercharger 24 is activated or not, blow-by gas is discharged from the same part inside the engine (specifically, the part where the oil separator 45 is attached to the crankcase 14), and the same part inside the engine. Specifically, outside air is introduced into the head cover 13 where the oil separator 47 is attached. Therefore, the flow direction of blow-by gas and the flow direction of outside air inside the engine can be made almost constant. Therefore, although the operating state and the non-operating state of the supercharger 24 are switched, the flow of blow-by gas inside the engine and the flow of outside air are not greatly disturbed with this, and the ventilation of the blow-by gas inside the engine is reduced. Can be done efficiently.

As described above, according to the present embodiment, the effects described below can be obtained.
(1) An air cleaner 28 incorporating two filters 28A and 28B is provided in the intake passage 20, and the first breather passage 41 and the second breather passage 42 are connected to a portion of the intake passage 20 downstream of the air cleaner 28, The introduction passage 43 is connected to a portion between the filters 28A and 28B of the air cleaner 28. Therefore, a pressure difference is generated between the upstream side (air cleaner internal pressure P1) and the downstream side (air cleaner downstream pressure P2) of the downstream filter 28B of the two filters, regardless of the operating state of the internal combustion engine 10. be able to. This pressure difference enables stable introduction of outside air through the introduction passage 43 and discharge of the blow-by gas through the first breather passage 41 and the second breather passage 42 together. Ventilation can be suitably performed.

  (2) Ventilation of the blow-by gas inside the engine can be performed through the first breather passage 41 and the introduction passage 43 during non-supercharging, and can be performed through the second breather passage 42 and the introduction passage 43 during supercharging. Therefore, the blow-by gas inside the engine can be favorably ventilated regardless of the presence or absence of supercharging.

  (3) The communicating portion on the crankcase 14 side of the first breather passage 41 and the second breather passage 42 is the same portion. Therefore, the flow direction of blow-by gas inside the engine and the flow direction of outside air can be made almost constant, and the blow-by gas inside the engine can be ventilated efficiently.

  (4) Since the PCV valve 44 is provided in the first breather passage 41, the amount of blow-by gas discharged from the engine at the time of non-supercharging can be accurately adjusted in accordance with the state of blow-by gas generation. .

The embodiment described above may be modified as follows.
Instead of providing the PCV valve 44 in the first breather passage 41, a check valve that allows only gas discharge from the crankcase 14 to the intake passage 20 may be provided.

Instead of providing the check valve 46 in the second breather passage 42, a PCV valve that allows only gas discharge from the crankcase 14 to the intake passage 20 may be provided.
As shown in FIG. 3, when the air cleaner downstream pressure P2 is lower than the predetermined pressure, the passage cross-sectional area of the second breather passage 42 is made smaller than when the air cleaner downstream pressure P2 is equal to or higher than the predetermined pressure. A discharge restriction valve 50 may be newly provided. According to this configuration, when the air cleaner downstream pressure P2 becomes low during supercharging, it is possible to suppress the pressure inside the engine from becoming excessively low due to this. As a result, for example, it is possible to suppress a decrease in reliability of the seal member for preventing gas outflow from the inside of the engine to the outside or gas intrusion to the inside of the engine, and suppress a decrease in reliability of the internal combustion engine 10. be able to. The exhaust restriction valve 50 may be, for example, a restriction valve that blocks communication between the intake passage 20 and the crankcase 14 through the second breather passage 42 when the air cleaner downstream pressure P2 is lower than a predetermined pressure, or an air cleaner downstream pressure P2. It is possible to employ a limiting valve or the like whose opening degree decreases as the value decreases.

  The first breather passage 41 may be omitted. Even in the same configuration, the pressure (air cleaner downstream pressure P2) of the communication portion of the second breather passage 42 in the intake passage 20 is higher than the pressure of the communication portion of the introduction passage 43 (air cleaner internal pressure P1) regardless of whether supercharging is performed. Therefore, the blow-by gas inside the engine can be ventilated based on the pressure difference (P1> P2).

  As shown in FIG. 4, instead of the air cleaner 28, an upstream air cleaner 61 is provided in the intake passage 20, and a downstream air cleaner 62 is provided in a portion downstream of the upstream air cleaner 61 in the intake passage 20. Also good. In this configuration, the introduction passage 43 is communicated with a portion of the intake passage 20 between the upstream air cleaner 61 and the downstream air cleaner 62, and the intake passage 20 has a second portion downstream of the downstream air cleaner 62. The two breather passages 42 may be communicated with each other.

  According to such a configuration, pressure in the downstream air cleaner 62 (specifically, its built-in filter) causes a pressure loss in a portion of the intake passage 20 downstream of the downstream air cleaner 62 (depending on the operating state of the internal combustion engine 10). The air cleaner downstream pressure P5) becomes lower than the pressure in the upstream portion (air cleaner intermediate pressure P6). Then, by this pressure difference (P6> P5), both the blow-by gas discharge through the first breather passage 41 (see FIG. 1) and the second breather passage 42 and the outside air introduction through the introduction passage 43 are stably performed. be able to.

  Instead of the air cleaner 28, as shown in FIG. 5, an air cleaner 71 containing only one filter 71A may be provided in the intake passage 20. In the same configuration, the introduction passage 43 is communicated with a portion of the air cleaner 71 that is in the middle of the filter 71A in the intake flow direction (a portion that is between the upstream end portion and the downstream end portion of the filter 71A). What should I do?

  According to such a configuration, the pressure at the downstream side of the air cleaner 71 in the intake passage 20 (air cleaner downstream pressure P7) does not depend on the operating state of the internal combustion engine 10 due to the pressure loss generated in the filter 71A of the air cleaner 71. It becomes lower than the pressure of the “corresponding portion” (air cleaner intermediate pressure P8). And by this pressure difference (P8> P7), both the blow-by gas discharge through the first breather passage 41 (see FIG. 1) and the second breather passage 42 and the outside air introduction through the introduction passage 43 are stably performed. be able to.

  In place of the air cleaner 28, an air cleaner incorporating three or more filters arranged at intervals in the intake flow direction may be provided. It is also possible to provide three or more air cleaners in the intake passage 20 at intervals in the intake flow direction. In short, if one or more filters are disposed in a portion of the intake passage 20 between the communication portion of the introduction passage 43 and the communication portion of the second breather passage 42, the internal structure and number of the air cleaners, etc. Can be arbitrarily changed.

  The present invention is not limited to an internal combustion engine equipped with an exhaust-driven supercharger, but can also be applied to an internal combustion engine equipped with an engine (crankshaft) -driven supercharger, a so-called supercharger. The present invention can also be applied to an internal combustion engine that is not provided with an intercooler.

The present invention can also be applied to an internal combustion engine that is not provided with a supercharger.
FIG. 6 shows an example of such an internal combustion engine. As shown in FIG. 6, the air intake passage 81 of the internal combustion engine 80 is provided with an air cleaner 28 and a throttle valve 30 in order from the upstream side. The blow-by gas processing apparatus includes a breather passage 82 and an introduction passage 83. The breather passage 82 is a passage that communicates a portion of the intake passage 81 downstream of the throttle valve 30 with the inside of the crankcase 14. The breather passage 82 is provided with a PCV valve 84 that allows only gas discharge from the crankcase 14 to the intake passage 81. The introduction passage 83 is a passage that communicates the interior of the air cleaner 28 (specifically, the portion between the two filters 28A and 28B) and the interior of the head cover 13. In the same configuration, the PCV valve 84 functions as a limiting valve.

  In such an internal combustion engine 80, basically, a pressure difference generated between the upstream side and the downstream side of the filter 28B on the downstream side of the two filters and a negative pressure generated on the downstream side of the throttle valve 30 ( Due to the negative intake pressure), the pressure at the communication portion of the breather passage 82 in the intake passage 81 (throttle downstream pressure P9) is lower than the pressure at the communication portion of the introduction passage 83 in the air cleaner 28 (air cleaner internal pressure P10) (P10). > P9). The blow-by gas inside the engine is ventilated through the breather passage 82 and the introduction passage 83 based on this pressure difference.

  Here, in the internal combustion engine 80, if the opening of the throttle valve 30 increases due to an increase in the load or the like, the intake negative pressure decreases or disappears. In the above configuration, even in such a case, the difference between the throttle downstream pressure P9 and the air cleaner internal pressure P10 is secured by the pressure difference generated between the upstream side and the downstream side of the filter 28B. Gas ventilation can be performed.

Therefore, according to the above configuration, ventilation of the blow-by gas inside the engine can be suitably executed without depending on the opening degree of the throttle valve 30.
Incidentally, as a matter of course, in the above-described configuration, the above-described air cleaner (the air cleaner 61 (see FIG. 4), the air cleaner 71 (see FIG. 5), etc.) may be provided in place of the air cleaner 28.

  In the internal combustion engine 80 shown in FIG. 6, the end of the breather passage 82 on the side of the intake passage 81 is connected to the air cleaner 28 and the throttle valve 30 in the intake passage 81, as indicated by the alternate long and short dash line in FIG. 6. You may make it connect to the part between. Such a configuration can also be applied to an internal combustion engine in which the throttle valve 30 is not provided.

  Even in the above configuration, the difference between the throttle downstream pressure P9 and the air cleaner internal pressure P10 is caused by the pressure difference generated between the upstream side and the downstream side of the filter 28B. Therefore, ventilation of the blow-by gas inside the engine is performed based on the difference. Can be executed.

  The breather passage may be connected to the oil separator 47 provided in the head cover 13, and the introduction passage may be connected to the oil separator 45 provided in the crankcase 14.

  In addition, two oil separators may be provided at different positions of the head cover 13, and the introduction passage may be connected to one oil separator and the breather passage may be connected to the other oil separator. In this configuration, the blow-by gas from the crankcase 14 to the inside of the head cover 13 is determined by modifying the internal structure of the internal combustion engine, for example, by devising the shape of the communication passage 23 that connects the inside of the head cover 13 and the inside of the crankcase 14. It is desirable to have a structure in which the introduction and the outside air from the head cover 13 to the crankcase 14 are appropriately performed.

  Further, it is possible to provide two oil separators at different positions inside the crankcase 14 and connect the introduction passage to one oil separator and connect the breather passage to the other oil separator.

  Also with these configurations, outside air can be introduced into the engine from the intake passage and blow-by gas can be discharged from the inside of the engine into the intake passage without depending on the operating state of the internal combustion engine. In addition, when the above configuration is applied to an internal combustion engine equipped with a supercharger, the flow direction of blow-by gas and the flow direction of outside air inside the engine can be made almost constant regardless of the presence or absence of supercharging. .

  It is widely known that oil sludge that contributes to oil degradation is mainly generated inside the cylinder head 12 and the head cover 13 based on blow-by gas. Therefore, in order to suppress the generation of oil sludge, it is desirable to adopt a structure in which the introduction passage is connected to the head cover 13 and the outside air is directly sent into the head cover 13.

  When such a structure is adopted, it is desirable to connect the breather passage to the crankcase 14. As a result, it becomes possible to push out the gas containing the blow-by gas inside the engine by the outside air in the order of “the inside of the head cover 13 → the crankcase 14 → the intake passage 20”, and the entire inside of the engine can be efficiently ventilated.

If the intrusion of oil from the inside of the engine into the introduction passage or the breather passage is avoided, the oil separators 45 and 47 can be omitted.
In an internal combustion engine having a V-type cylinder arrangement, it is possible to employ a configuration in which an introduction passage is connected to the head cover of each bank and a breather passage is connected to a crankcase. Further, in an internal combustion engine having a V-type cylinder arrangement, it is possible to adopt a configuration in which the introduction passage is connected to the head cover of one bank and the breather passage is connected to the head cover of the other bank. Furthermore, in an internal combustion engine of a V-type cylinder arrangement, it is possible to adopt a configuration in which an introduction passage is connected to the crankcase and a breather passage is connected to a head cover of each bank.

  In any internal combustion engine, outside air can be introduced from the intake passage into the engine through the introduction passage, and blow-by gas can be discharged from the inside of the engine into the intake passage through the breather passage regardless of the operating state. In addition, when the above configuration is applied to an internal combustion engine equipped with a supercharger, the flow direction of blow-by gas and the flow direction of outside air inside the engine can be made almost constant regardless of the presence or absence of supercharging. .

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the specific structure about one Embodiment of the internal combustion engine with a blowby gas processing apparatus concerning this invention. Sectional drawing which shows the internal structure about the air cleaner provided in the internal combustion engine concerning the embodiment. The schematic diagram which shows the specific structure about the modification of the internal combustion engine concerning the embodiment. Schematic which shows the internal structure about the modification of an air cleaner. Schematic which shows the internal structure about the other modification of an air cleaner. The schematic diagram which shows the specific structure about the modification of an internal combustion engine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,80 ... 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 valve, 20 , 81 ... Intake passage, 21 ... Exhaust valve, 22 ... Exhaust passage, 23 ... Communication passage, 24 ... Supercharger, 25 ... Turbine wheel, 26 ... Compressor impeller, 27 ... Shaft, 28, 71 ... Air cleaner, 28A, 28B , 71A ... Filter, 29 ... Intercooler, 30 ... Throttle valve, 41 ... First breather passage, 42 ... Second breather passage, 43, 83 ... Introduction passage, 44, 84 ... PCV valve, 45, 47 ... Oil Separator, 46 ... Check valve, 50 ... Discharge limiting valve, 61 ... Upstream air cleaner, 62 ... Downstream air cleaner, 82 ... Riesa passage.

Claims (11)

A breather passage communicating the intake passage with the engine interior; and
An introduction passage that communicates a portion of the intake passage upstream of the breather passage with respect to the breather passage and the inside of the engine; and
An internal combustion engine with a blow-by gas processing device, comprising a filter that is provided in a portion of the intake passage between the communication portion of the introduction passage and the communication portion of the breather passage and filters the intake air passing through the intake passage. The internal combustion engine with a blow-by gas processing device according to claim 1,
The intake passage includes an air cleaner that incorporates two filters arranged at intervals in the intake flow direction;
The introduction passage communicates with a portion of the air cleaner between the two filters;
The internal combustion engine with a blow-by gas processing device, wherein the breather passage is communicated with a portion of the intake passage downstream of the two filters in the intake flow direction. The internal combustion engine with a blow-by gas processing device according to claim 1 or 2,
The intake passage is provided with a supercharger that performs supercharging by pumping the intake air flowing through the intake passage, and is arranged downstream of the filter in the intake flow direction, and a throttle that variably sets the cross-sectional area of the intake passage. A valve is disposed downstream of the supercharger in the direction of intake air flow,
The breather passage has a first one-way discharge valve that allows only gas discharge from the inside of the engine to the intake passage, and a portion of the intake passage on the downstream side in the intake flow direction from the throttle valve and the inside of the engine Between the filter and the supercharger in the intake passage having a first breather passage communicating with the first breather passage and a second one-way exhaust valve allowing only gas discharge from the inside of the engine to the intake passage. An internal combustion engine with a blow-by gas processing device, characterized in that it comprises a second breather passage that communicates this part with the interior of the engine. The internal combustion engine with a blow-by gas processing device according to claim 3,
The internal combustion engine with a blow-by gas processing device, wherein the first breather passage and the second breather passage have the same communication portion on the internal combustion engine side. When the pressure of the portion between the filter and the supercharger in the intake passage is lower than a predetermined pressure, the passage cross-sectional area of the second breather passage is made smaller than when the pressure is higher than the predetermined pressure. The internal combustion engine with a blow-by gas processing device according to claim 3 or 4, further comprising an exhaust restriction valve. In the internal combustion engine with a blow-by gas processing device according to any one of claims 3 to 5,
With the blow-by gas processing device, the first one-way exhaust valve is a differential pressure operating valve that is changed to a larger opening degree as the differential pressure between the engine inner side and the intake passage side is smaller. Internal combustion engine. In the internal combustion engine with a blow-by gas processing device according to any one of claims 3 to 6,
The internal combustion engine with a blow-by gas processing device, wherein the second one-way discharge valve is a check valve. The internal combustion engine with a blow-by gas processing device according to claim 1 or 2,
In the intake passage, a throttle valve that variably sets the cross-sectional area of the intake passage is disposed downstream of the filter in the intake flow direction.
The internal combustion engine with a blow-by gas processing device, wherein the breather passage communicates with a portion of the intake passage downstream of the throttle valve in the intake flow direction. The internal combustion engine with a blow-by gas processing device according to claim 8,
The breather passage is a control valve that allows only gas discharge from the inside of the engine to the intake passage and is changed to a larger opening as the difference between the pressure inside the engine and the pressure on the intake passage is smaller. An internal combustion engine equipped with a blow-by gas processing device. The internal combustion engine with a blow-by gas processing device according to claim 1 or 2,
In the intake passage, a supercharger that performs supercharging through pressure feeding of intake air flowing through the intake passage is disposed downstream of the filter in the intake flow direction.
The internal combustion engine with a blow-by gas processing device, wherein the breather passage communicates with a portion of the intake passage between the filter and the supercharger. An exhaust restriction that reduces the cross-sectional area of the breather passage when the pressure in the portion of the intake passage between the filter and the supercharger is lower than a predetermined pressure, compared to when the pressure is higher than the predetermined pressure The internal combustion engine with a blow-by gas processing device according to claim 10, further comprising a valve.

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