Patent Grant
7523748
The present invention relates to a blow-by gas processing apparatus which is applicable to an internal combustion engine provided with a supercharger.
A vehicle internal combustion engine can be provided with, for example, a blow-by gas processing apparatus. The blow-by gas processing apparatus recirculates a combustion gas leaking to a crank chamber from a gap between a cylinder and a piston of the engine, that is, a blow-by gas to an intake passage. Specifically, an intake negative pressure generated in a portion of the intake passage in a downstream side of a throttle valve draws the blow-by gas in an interior of the engine so as to circulate in a breather passage. The blow-by gas is returned to the intake passage from the breather passage, is again fed to the combustion chamber, and is burned. Accordingly, it is possible to reduce a discharge amount of a hydrocarbon (HC) to the atmosphere. Further, it is possible to inhibit the blow-by gas from deteriorating oil in the engine. As mentioned above, the blow-by gas processing apparatus ventilates the interior of the engine.
In the case that the supercharger is provided in the internal combustion engine, if the supercharger is operated, the intake negative pressure is lost.
Japanese Laid-Open Utility Model Publication No. 5-87213, Japanese Laid-Open Patent Publication No. 2006-144686 and Japanese Laid-Open Patent Publication No. 2004-60475 each disclose a blow-by gas processing apparatus which is applicable to an internal combustion engine provided with a supercharger.
As shown in
In the case that the supercharger 106 is not operated, that is, at a non-supercharging time, an intake negative pressure is generated in the downstream portion 105c. Accordingly, as shown by filled-in arrows in
Further, in the case that the supercharger 106 is operated, that is, at a supercharging time, the negative pressure is generated in the upstream portion 105a. As a result, as shown by open arrows in
However, in the blow-by gas processing apparatuses in the publications mentioned above, it is practically impossible to introduce the intake air into the interior of the engine at the supercharging time.
As shown in
At the non-supercharging time, an intake air existing within the upstream portion 124a flows through the common passage 123 so as to flow into the engine 120, and makes the interior of the engine 120 close to the atmospheric pressure. An intake negative pressure is generated in the downstream portion 124c. As a result, the blow-by gas in the engine 120 flows through the breather passage 122 so as to be drawn into the intake passage 124.
At the supercharging time, the intake air within the intermediate portion 124b flows through the introduction passage 121 so as to flow into the interior of the engine 120, thereby making the interior of the engine 120 higher pressure than the upstream portion 124a. Accordingly, the blow-by gas in the engine 120 flows through the common passage 123 so as to be drawn into the intake passage 124.
As a result, at both of the supercharging time and the non-supercharging time, the blow-by gas in the engine 120 is recirculated to the intake passage, and the intake air can be introduced to the interior of the engine 120. However, the blow-by gas flow in the engine 120 is different between the supercharging time and the non-supercharging time. Further, the intake air flow in the engine 120 is different between the supercharging time and the non-supercharging time. In other words, filled-in arrows and open arrows shown in
As shown in
At the non-supercharging time, the intake negative pressure is generated in the downstream portion 143c. As a result, the blow-by gas in the engine 140 flows through the first common passage 141, and is drawn into the downstream portion 143c. The intake air within the upstream portion 143a flows through the second common passage 142 so as to flow into the interior of the engine 140.
At the supercharging time, the intake air within the downstream portion 143c flows through the first common passage 141 and the bypass passage 146, and flows into the interior of the engine 140. Since the negative pressure is generated by the supercharger 147 in the upstream portion 143a, the blow-by gas in the engine 140 flows through the second common passage 142 so as to be drawn into the intake passage 143.
In this case, as shown in
An objective of the present invention is to provide a blow-by gas processing apparatus which can efficiently ventilate the interior of an engine.
In accordance with one aspect of the present invention, a blow-by gas processing apparatus applicable to an internal combustion engine is provided. An intake passage extends from the engine. An intake air flows from an upstream side to a downstream side in the intake passage, whereby the intake air flows toward the engine. A supercharger and a throttle valve are arranged in the intake passage. A throttle valve is positioned in a downstream side of the supercharger. The supercharger pressure feeds the intake air flowing through the intake passage toward the engine, thereby supercharging the intake air to the engine. The throttle valve variably sets a passage cross-sectional area of the intake passage. The intake passage has an upstream portion which is provided on an upstream side of the supercharger, an intermediate portion which is provided between the supercharger and the throttle valve, and a downstream portion which is provided on a downstream side of the throttle valve. The processing apparatus has a first breather passage, a second breather passage, and an introduction passage. The first breather passage connects the interior of the engine with the downstream portion. The first breather passage communicates with the interior of the engine in a first communicating portion. The first breather passage has a first one-way discharge valve allowing only a gas discharge from the interior of the engine to the intake passage. The second breather passage connects the interior of the engine with the upstream portion. The second breather passage communicates with the interior of the engine in a first communicating portion. The second breather passage has a second one-way discharge valve allowing only a gas discharge from the interior of the engine to the upstream portion. The introduction passage connects the upstream portion with the interior of the engine at the non-supercharging time, and connects at least one of the intermediate portion and the downstream portion with the interior of the engine at the supercharging time.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
As shown in
A cylinder 16 is formed in the cylinder block 11. A piston 17 is arranged in the cylinder 16 so as to reciprocate. The engine 10 has a combustion chamber 18. An inner peripheral wall of the cylinder 16, a top surface of the piston 17, and a lower surface of the cylinder head 12 define the combustion chamber 18. An intake passage 20 is connected to the combustion chamber 18 via an intake valve 19, and an exhaust passage 22 is connected thereto via an exhaust valve 21. In other words, each of the intake passage 20 and the exhaust passage 22 extends from the engine 10. A communicating passage 23 is formed in the engine 10. The communicating passage 23 extends in such a manner as to communicate the interior of the head cover 13 with the crank chamber 14a.
One exhaust-driven supercharger 24 is provided in the intake passage 20 and the exhaust passage 22. The supercharger 24 is provided with a turbine wheel 25 provided in the exhaust passage 22, and a compressor impeller 26 provided in the intake passage 20. The shaft 27 couples the turbine wheel 25 to the compressor impeller 26 in such a manner as to be integrally rotatable.
If the amount of the exhaust gas flowing through the exhaust passage 22 becomes large so as to be sprayed to the turbine wheel 25, the turbine wheel 25 and the compressor impeller 26 are integrally rotated. Accordingly, the intake air flowing through the intake passage 20 is forcibly pressure fed to the combustion chamber 18. In other words, the supercharger 24 supercharges the intake air to the combustion chamber 18. The supercharger 24 is not operated in the case that a load of the engine 10 is close to zero (work load≈0), and is operated in the case that the load of the engine 10 is large (work load>>0). In other words, the supercharger 24 is not operated in the case that the amount of the exhaust gas flowing through the exhaust passage 22 is small, and is operated in the case that the amount of the exhaust gas is large.
The intake air flows from an upstream side to a downstream side in the intake passage 20, whereby the intake air flows toward the engine 10. In other words, the intake air in the intake passage 20 flows from an upstream side in an intake air flowing direction toward a downstream side, thereby moving toward the engine 10. From the upstream side toward the downstream side in the intake passage 20, an air cleaner 28, the compressor impeller 26, an intercooler 29, and a throttle valve 30 are arranged in this order. The air cleaner 28 filtrates the intake air. The intercooler 29 lowers a temperature of the intake air by executing a heat exchange between the intake air and the external ambient atmosphere. The throttle valve 30 is a throttle valve variably setting a passage cross-sectional area of the intake passage 20. The turbine wheel 25 is arranged in the exhaust passage 22.
The intake passage 20 has an upstream portion 20a, an intermediate portion 20b and a downstream portion 20c. The upstream portion 20a corresponds to a portion of the intake passage 20 between the air cleaner 28 and the supercharger 24. In other words, the upstream portion 20a corresponds to a portion of the intake passage 20 in an upstream side of the supercharger 24. The intermediate portion 20b corresponds to a portion of the intake passage 20 between the supercharger 24 and the throttle valve 30. In other words, the upstream portion 20a and the intermediate portion 20b correspond to a portion of the intake passage 20 in an upstream side of the throttle valve 30. The downstream portion 20c corresponds to a portion of the intake passage 20 in a downstream side of the throttle valve 30. A pressure of the upstream portion 20a is referred to as an upstream pressure P2, and a pressure of the downstream portion 20c is referred to as a downstream pressure P1. A pressure in the engine 10 is referred to as engine internal pressure P3. In other words, the engine internal pressure P3 indicates a pressure in the head cover 13 and the crank chamber 14a. A pressure of the intermediate portion 20b is referred to as an intermediate pressure P4. The state in which the downstream pressure P1 is made higher than the atmospheric pressure by the operation of the supercharger 24 is referred to as “supercharging time”, and the state in which the downstream pressure P1 is lower than the atmospheric pressure is referred to as “non-supercharging time.”
Combustion gas in the combustion chamber 18 passes through a gap of sliding surfaces between the cylinder 16 and the piston 17, and leaks to the crank chamber 14a. The combustion gas leaking as mentioned above corresponds to a blow-by gas. Hereinafter, the blow-by gas leaking to the crank chamber 14a from the combustion chamber 18 may be referred to as a leaked blow-by gas. The engine 10 is provided with a blow-by gas processing apparatus recirculating the blow-by gas to the intake passage 20.
The blow-by gas processing apparatus is provided with a first breather passage 41, a second breather passage 42, a first introduction passage 43, and a second introduction passage 44. Each of the first breather passage 41 and the second breather passage 42 recirculates the blow-by gas in the crank chamber 14a to the intake passage 20. In other words, the blow-by gas in the engine 10 passes through the first breather passage 41 or the second breather passage 42, and is recirculated to the intake passage 20. Each of the first introduction passage 43 and the second introduction passage 44 introduces an intake air of the intake passage 20 into the interior of the head cover 13. In other words, the intake air in the intake passage 20 passes through the first introduction passage 43 or the second introduction passage 44, and flows into the interior of the engine 10.
The first breather passage 41 connects the crank chamber 14a with the downstream portion 20c. A first positive crankcase ventilation (PCV) valve 46 is arranged in the first breather passage 41.
The first PCV valve 46 corresponds to a one-way valve, and a differential pressure valve. In the case that the pressure in the crank chamber 14a, that is, the engine internal pressure P3 is higher than the downstream pressure P1, the more increased the pressure difference between them, the more reduced the opening degree of the first PCV valve 46 becomes. In the case that the engine internal pressure P3 is equal to or less than the downstream pressure P1, the first PCV valve 46 is closed. The first PCV valve 46 corresponding to the first one-way discharge valve allows the blow-by gas in the crank chamber 14a to recirculate to the intake passage 20, however, inhibits the intake air within the intake passage 20 from flowing into the crank chamber 14a. As mentioned above, the first PCV valve 46 autonomously regulates a flow rate of the blow-by gas passing through the first breather passage 41 on the basis of the pressure difference between the crank chamber 14a and the downstream portion 20c.
A first oil separator 45 is arranged in the crankcase 14. The first oil separator 45 separates oil mist from the blow-by gas. The first PCV valve 46 is connected to the first oil separator 45. In other words, an inlet of the first breather passage 41 is connected to the crank chamber 14a via the first PCV valve 46 and the first oil separator 45. The first oil separator 45 corresponds to a portion of the engine 10 communicating with the first breather passage 41, that is, a first communicating portion. An outlet of the first breather passage 41 is connected to the downstream portion 20c.
The second breather passage 42 connects the crank chamber 14a with the upstream portion 20a. A first check valve 48 is provided in the middle of the second breather passage 42. The first check valve 48 corresponding to a second one-way discharge valve allows the blow-by gas in the crank chamber 14a to flow through the second breather passage 42 so as to recirculate to the intake passage 20, however, inhibits the intake air within the intake passage 20 from flowing through the second breather passage 42 so as to flow into the crank chamber 14a.
An inlet of the second breather passage 42 is connected to the first oil separator 45. In other words, both of the inlet of the first breather passage 41 and the inlet of the second breather passage 42 communicate with the first oil separator 45 serving as the first communicating portion.
The first introduction passage 43 connects the upstream portion 20a with the interior of the head cover 13. A check valve 49 is provided in the middle of the first introduction passage 43. The check valve 49 allows the intake air within the intake passage 20 to flow through the first introduction passage 43 so as to flow into the interior of the head cover 13, however, inhibits the blow-by gas in the head cover 13 from flowing through the first introduction passage 43 so as to be discharged to the intake passage 20. In other words, the check valve 49 corresponds to a first one-way introduction valve.
A second oil separator 47 separating oil mist from the blow-by gas is arranged in the head cover 13. An outlet of the first introduction passage 43 is connected to the second oil separator 47. In other words, the first introduction passage 43 communicates with the interior of the head cover 13 via the second oil separator 47. In other words, the second oil separator 47 corresponds to a second communicating portion serving as a portion of the engine 10 communicating with the first introduction passage 43.
The second introduction passage 44 connects the downstream portion 20c with the interior of the head cover 13. An inlet of the second introduction passage 44 is connected to the downstream portion 20c via the second PCV valve 50. An outlet of the second introduction passage 44 is connected to the second oil separator 47. In other words, both of the outlet of the first introduction passage 43 and the outlet of the second introduction passage 44 communicate with the second oil separator 47 serving as the second communicating portion.
The second PCV valve 50 corresponds to a one-way valve, and a differential pressure valve. The second PCV valve 50 corresponding to the one-way introduction valve allows the intake air in the downstream portion 20c to be introduced into the interior of the head cover 13, however, inhibits the blow-by gas in the head cover 13 from flowing out to the intake passage 20. In the case that the downstream pressure P1 is equal to or less than the engine internal pressure P3, the second PCV valve 50 is closed. In the case that the downstream pressure P1 is higher than the engine internal pressure P3, the more increased the pressure difference between them, the more reduced the opening degree of the second PCV valve 50 becomes. In other words, the more reduced the pressure difference between the engine internal pressure P3 and the downstream pressure P1, the more increased the opening degree of the second PCV valve 50 becomes. As mentioned above, the second PCV valve 50 autonomously regulates the flow rate of the intake air passing through the first breather passage 41 on the basis-of the pressure difference between the interior of the head cover 13 and the downstream portion 20c.
Next, a description will be given of an operation of the blow-by gas processing apparatus.
The intake air introduction into the interior of the head cover 13 passes through different paths respectively at the supercharging time and the non-supercharging time. The blow-by gas discharge from the crank chamber 14a passes through different paths respectively at the supercharging time and the non-supercharging time.
The filled-in arrows in
At the non-supercharging time, the downstream pressure P1 is lower than the atmospheric pressure, and the upstream pressure P2 is substantially equal to the atmospheric pressure. In other words, at the non-supercharging time, the downstream pressure P1 is lower than the upstream pressure P2 (P1<P2).
Accordingly, at the non-supercharging time, the intake air within the upstream portion 20a flows through the first introduction passage 43 so as to flow into the interior of the head cover 13. As a result, the engine internal pressure P3 is higher than the downstream pressure P1. The pressure difference between the engine internal pressure P3 and the downstream pressure P1 makes the blow-by gas in the engine 10 flow to the first breather passage 41 so as to recirculate to the intake passage 20.
In other words, at the non-supercharging time, the intake air within the first introduction passage 43 is introduced to the interior of the head cover 13, and the blow-by gas in the crank chamber 14a flows through the first breather passage 41 so as to be discharged to the intake passage 20. Accordingly, at the non-supercharging time, the interior of the engine 10 is ventilated.
At the non-supercharging time, if the opening degree of the throttle valve 30 is increased, the intake air amount of the engine 10 is also increased. As a result, a generating amount of the blow-by gas is also increased. If the opening, degree of the throttle valve 30 is increased, the downstream pressure P1 is increased. Accordingly, the pressure difference between the downstream pressure P1 and the upstream pressure P2 is reduced, and the pressure difference between the downstream pressure P1 and the engine internal pressure P3 is reduced in the same manner. As a result, the opening degree of the first PCV valve 46 is increased. Accordingly, the amount of the blow-by gas flowing through the first breather passage 41 so as to be recirculated to the downstream portion 20c from the interior of the engine 10 is ensured. Therefore, the first PCV valve 46 accurately regulates the discharge amount of the blow-by gas from the interior of the engine 10 in correspondence to the generating condition of the blow-by gas.
On the other hand, the downstream pressure P1 is equal to or higher than the atmospheric pressure, and the upstream pressure P2 is lower than the atmospheric pressure. In other words, at the supercharging time, the upstream pressure P2 is lower than the downstream pressure P1 (P2<P1).
Accordingly, at the supercharging time, the blow-by gas in the crank chamber 14a passes through the second breather passage 42, and is recirculated to the upstream portion 20a. As a result, the engine internal pressure P3 is lower than the downstream pressure P1 (P3<P1). Therefore, the intake air in the downstream portion 20c flows through the second introduction passage 44 so as to flow into the interior of the head cover 13.
In other words, at the supercharging time, the intake air within the downstream portion 20c flows through the second introduction passage 44 so as to be introduced to the interior of the head cover 13. The blow-by gas in the crank chamber 14a flows through the second breather passage 42 so as to be discharged to the upstream portion 20a. As a result, at the supercharging time, the interior of the engine 10 is also ventilated.
The pressure difference between the downstream pressure P1 and the engine internal pressure P3 is changed in correspondence to the operating state of the supercharger 24. The generating amount of the blow-by gas in the engine 10 is also changed in correspondence to the operating state of the supercharger 24. Since the opening degree of the second PCV valve 50 is changed in correspondence to the pressure difference between the downstream pressure P1 and the engine internal pressure P3, the second PCV valve 50 regulates the intake air introducing amount to the interior of the engine 10 in such a manner as to match to the generating condition of the blow-by gas.
In accordance with the present embodiment, at both of the supercharging time and the non-supercharging time, the blow-by gas in the engine 10 is recirculated to the intake passage 20. Further, the intake air within the intake passage 20 is introduced to the interior of the engine 10 at both of the supercharging time and the non-supercharging time. Accordingly, the present embodiment efficiently ventilates the interior of the engine 10, for example, in comparison with the case wherein the blow-by gas discharge or the intake air introduction is not executed at the non-supercharging time or the supercharging time. Therefore, it is possible to suppress the discharge amount of a hydrocarbon (HC) to the atmosphere. Further, it is possible to suppress an oil deterioration caused by mixing of a fuel component in the blow-by gas. Further, it is possible to suppress an accumulation amount of oil sludge generated on the basis of the blow-by gas.
Both of the outlet of the first introduction passage 43 and the outlet of the second introduction passage 44 are connected to the head cover 13. Generally, if the blow-by gas deteriorates the oil, oil sludge is generated. Oil sludge can be generated in the crank chamber 14a and/or the interior of the head cover 13, and the oil sludge can be more easily generated in the interior of the head cover 13. Since the first introduction passage 43 and the second introduction passage 44 in accordance with the present embodiment can directly feed the intake air to the interior of the head cover 13, it is possible to suppress the generation of the oil sludge more efficiently.
Both of the first breather passage 41 and the inlet of the second breather passage 42 are connected to the crank chamber 14a. Accordingly, the intake air introduced to the interior of the head cover 13 from the first introduction passage 43 and the second introduction passage 44 efficiently pushes out the blow gas in the order of the interior of the head cover 13, the crank chamber 14a, and the intake passage 20. In other words, the entire interior of the engine 10 is efficiently ventilated.
In the case that the flowing direction of the blow-by gas discharged from the interior of the engine 10 is different between the supercharging time and the non-supercharging time, and the flowing direction of the intake air introduced to the interior of the engine 10 is further different between the supercharging time and the non-supercharging time, the blow-by gas flow in the engine 10 and the intake air flow in the engine 10 can become disturbed each time there is a switch between the operating state and the non-operating state of the supercharger 24. For example, the blow-by gas flow and the intake air flow in the engine 10 can stagnate temporarily. For example, in the case that the flowing direction of the blow-by gas in the engine 10, and the flowing direction of the intake air are switched in the opposite directions between the supercharging time and the non-supercharging time, the blow-by gas discharged from the interior of the engine 10 can be again returned to the interior of the engine 10. Further, the intake air introduced to the interior of the engine 10 can be again returned to the outer portion of the engine 10. In both of these cases, it is impossible to efficiently ventilate the interior of the engine 10. In other words, it is impossible to efficiently discharge the blow-by gas in the engine 10.
In the present embodiment, the flowing direction of the blow-by gas from the interior of the engine 10 toward the first breather passage 41 and the second breather passage 42 is always constant regardless of whether it is the supercharging time or the non-supercharging time. In the same manner, the flowing direction of the intake air flowing to the interior of the engine 10 from the first introduction passage 43 and the second introduction passage 44 is always constant regardless of whether it is the supercharging time or the non-supercharging time.
In the present embodiment, the inlet of the first breather passage 41, and the inlet of the second breather passage 42 are connected to the first oil separator 45 corresponding to the common portion (the same portion) in the engine 10. In other words, the blow-by gas in the engine 10 is always discharged to the outer portion from the first oil separator 45 with or without the operation of the supercharger 24. In other words, the blow-by gas in the engine 10 is discharged from the connecting portion of the first oil separator 45 in the crank chamber 14a. Further, both of the outlet of the first introduction passage 43 and the outlet of the second introduction passage 44 are connected to the second oil separator 47. In other words, the intake air is always introduced to the interior of the engine 10 from the second oil separator 47 with or without the operation of the supercharger 24. In other words, the intake air is introduced to the interior of the engine 10 from the connecting portion of the second oil separator 47 in the head cover 13. Accordingly, it is possible to fix each of the flowing direction of the blow-by gas in the engine 10 and the flowing direction of the intake air in the engine 10 with or without the operation of the supercharger 24. Accordingly, even if the operation is switched to the supercharging time and the non-supercharging time, the blow-by gas flow and the intake air flow in the engine 10 do not become largely disturbed. Therefore, the present embodiment can efficiently ventilate the interior of the engine 10.
The first embodiment has the following advantages.
(1) At the non-supercharging time, the intake air within the first introduction passage 43 is introduced to the interior of the head cover 13. The blow-by gas in the crank chamber 14a flows through the first breather passage 41 so as to be discharged to the intake passage 20. At the supercharging time, the intake air within the downstream portion 20c flows through the second introduction passage 44 so as to be introduced to the interior of the head cover 13. The blow-by gas in the crank chamber 14a flows through the second breather passage 42 so as to be discharged to the upstream portion 20a. Accordingly, the flow in the engine 10 is not changed between the supercharging time and the non-supercharging time, and it is possible to efficiently ventilate the blow-by gas in the engine 10.
(2) The second introduction passage 44 is provided with the second PCV valve 50. Accordingly, it is possible to regulate the intake air introducing amount to the interior of the engine 10 in such a manner as to match to the generating condition of the blow-by gas at the supercharging time.
(3) The first breather passage 41 is provided with the first PCV valve 46. Accordingly, it is possible to accurately regulate the discharge amount of the blow-by gas from the interior of the engine 10 in correspondence to the generating condition of the blow-by gas at the non-supercharging time.
The first embodiment may be modified as follows.
The structure is not limited to be made such that the first introduction passage 43 is provided with the check valve 49, and the first breather passage 41 is provided with the first PCV valve 46. Conversely, the structure may be made such that the first introduction passage 43 is provided with a PCV valve, and the first breather passage 41 is provided with a check valve. The PCV valve allows only the gas introduction from the intake passage 20 to the interior of the head cover 13. The check valve allows only the gas discharge from the crank chamber 14a to the intake passage 20.
Further, the structure may be made such that the first introduction passage 43 is provided with a PCV valve, and the first breather passage 41 is also provided with the first PCV valve 46. In other words, a PCV valve may be provided in at least one of the first introduction passage 43 and the first breather passage 41. These PCV valves regulate the blow-by gas discharge amount from the interior of the engine 10, and the intake air introducing amount to the interior of the engine 10 in correspondence to the blow-by gas generation status, on the basis of the pressure difference between the downstream pressure P1 and the upstream pressure P2, at the non-supercharging time.
The structure is not limited to be made such that the second introduction passage 44 is provided with the second PCV valve 50, and the second breather passage 42 is provided with the first check valve 48. Conversely, the structure may be made such that the second introduction passage 44 is provided with a check valve, and the second breather passage 42 is provided with a PCV valve. The check valve allows only the gas introduction from the intake passage 20 to the interior of the head cover 13. The PCV valve allows only the gas discharge from the crank chamber 14a to the intake passage 20. Further, the structure may be made such that the second introduction passage 44 is provided with the second PCV valve 50, and the second breather passage 42 is provided with another PCV valve. In other words, the PCV valve may be provided in at least one of the second introduction passage 44 and the second breather passage 42. The PCV valve regulates the blow-by gas discharge amount from the interior of the engine 10, and the intake air introducing amount to the interior of the engine 10, on the basis of the pressure difference between the downstream pressure P1 and the upstream pressure P2, at the supercharging time.
In the case that the second introduction passage 44 is provided with a check valve, the second introduction passage 44 may be further provided with an introduction limit valve. The introduction limit valve reduces a passage cross-sectional area of the second introduction passage 44 if the downstream pressure P1 is increased. The introduction limit valve inhibits the engine internal pressure P3 from being excessively increased due to the increase of the downstream pressure P1. Accordingly, it is possible to prevent a reliability of the seal member in the engine 10 from being lowered. The seal member prevents the gas outflow from the interior of the engine 10 to the outer portion, and prevents the gas from making an intrusion into the interior of the engine 10. In other words, the introduction limit valve can suppress the reduction of the reliability of the engine 10. The introduction limit value may be structured such as to shut off the second introduction passage 44 in the case that the downstream pressure P1 is equal to or more than a predetermined pressure, or may be structured such as to gradually reduce the opening degree of the second introduction passage as the downstream pressure P1 is increased.
As shown in
However, the throttle portion 59 in
Further, the third embodiment has the throttle portion 59 in place of the check valve 49. In other words, the third embodiment reduces one part which has a movable portion. Accordingly, it is possible to improve a reliability of the blow-by gas processing apparatus.
As shown in
On the assumption that the outlet of the first introduction passage 43, and the outlet of the second introduction passage 44 communicate with the interior of the head cover 13 via the common second oil separator 47, the outlet of the first introduction passage 43 can directly communicate with the outlet of the second introduction passage 44, in the second oil separator 47. Since the first introduction passage 43 is only provided with the throttle portion 59 in place of the check valve 49, the intake air in the second introduction passage 44 can flow into the first introduction passage 43, at the supercharging time.
However, in the case of
Further, as shown by a one-dot chain line in
At the non-supercharging time, the downstream pressure P1 is lower than the upstream pressure P2 and the intermediate pressure P5 (or P4 in the case shown by a one-dot chain line in
In the case shown in
In the case that the first introduction passage 63 is provided with a check valve, the first introduction passage 63 may be provided with an introduction limit valve. The introduction limit valve reduces the passage cross-sectional area of the first introduction passage 63 as the intermediate pressure P5 (or P4) is increased. The introduction limit valve inhibits the engine internal pressure P3 from being excessively increased due to the high intermediate pressure P5 (or P4), at the supercharging time. In other words, the introduction control valve suppresses the reduction of the reliability of the engine 10. The introduction limit valve may be structured such as to shut off the first introduction passage 63 in the case that the intermediate pressure P5 (or P4) is equal to or more than a predetermined pressure, or may be structured such as to gradually reduce the opening degree of the first introduction passage 63 as the intermediate pressure P5 (or P4) is increased.
The third PCV valve 65 shown in
At the supercharging time, the upstream pressure P2 is lower than the intermediate pressure P4 (or P5) (P2<P4 (or P5)). Accordingly, the pressure difference between the intermediate pressure P4 (or P5) and the upstream pressure P2 introduces the intake air in the second introduction passage 74 into the interior of the engine 10, and discharges the blow-by gas in the engine 10 from the second breather passage 42 to the intake passage 20.
In the case shown in
In the case that the second introduction passage 74 is provided with a check valve, the second introduction passage 74 may be provided with an introduction limit valve. The introduction limit valve reduces the passage cross-sectional area of the second introduction passage 74 as the intermediate pressure P4 (or P5) is increased. The introduction limit valve can suppress the engine internal pressure P3 from being excessively increased due to the high intermediate pressure P4 (or P5), at the supercharging time. In other words, it is possible to suppress the reduction of the reliability of the engine 10. The introduction limit valve may be structured such as to shut off the second introduction passage 74 in the case that the intermediate pressure P4 (or P5) is equal to or more than a predetermined pressure, or may be structured such as to gradually reduce the opening degree of the second introduction passage 74 as the intermediate pressure P4 (or P5) is increased.
The check valve 49 may be omitted from the first introduction passage 43, and the first introduction passage 43 may be provided with a throttle portion. The throttle portion reduces the passage cross-sectional area of the first introduction passage 43. The throttle portion allows the intake air introduction from the intake passage 20 to the interior of the head cover 13, on the basis of the pressure difference between the downstream pressure P1 and the upstream pressure P2, at the non-supercharging time. The second introduction passage 74 introduces the intake air from the intake passage 20 to the interior of the head cover 13, on the basis of the pressure difference between the intermediate pressure P4 (or P5) and the downstream pressure P1, at the supercharging time. The throttle portion suppresses the amount of the gas flowing through the first introduction passage 43 from the interior of the head cover 13 so as to be discharged to the intake passage 20. Accordingly, the flowing direction of the blow-by gas in the engine 10, and the flowing direction of the intake air are substantially constant without being changed. Further, in order to set the throttle portion in place of the check valve 49, in the first introduction passage 43, it is possible to reduce one part having a movable portion. Accordingly, it is possible to improve the reliability of the blow-by gas processing apparatus.
In the case of
At the non-supercharging time, the intermediate pressure P5 (or P4) serving as the introduction portion pressure is higher than the downstream pressure P1 (P1<P5 (or P4)). Accordingly, at the non-supercharging time, the common introduction passage 83 can introduce the intake air in the intermediate portion 20b to the interior of the head cover 13, on the basis of the pressure difference between the intermediate pressure P5 (or P4) and the downstream pressure P1. At the supercharging time, the intermediate pressure P5 (or P4) is higher than the upstream pressure P2. Accordingly, at the supercharging time, the common introduction passage 83 can introduce the intake air in the intermediate portion 20b to the interior of the head cover 13 on the basis of the pressure difference between the intermediate pressure P5 (or P4) and the upstream pressure P2.
As shown in
In this case, if there is no risk that the engine internal pressure P3 becomes excessively higher at the supercharging time, the introduction limit valve 82 shown in
The first breather passage 41 shown in
The introduction limit valve 82 shown in
The various PCV valves and check valves mentioned above may be replaced by electromagnetic control valves. An opening degree of the electromagnetic control valve is controlled on the basis of the engine internal pressure P3, or the pressure (P1, P2, P5 (or P4)) of the intake passage 20.
As shown in
As shown in
As shown in
If it is possible to avoid the oil intrusion from the interior of the engine 10 to the first breather passage 41 and the second breather passage 42, the first oil separator 45 may be omitted. Further, if it is possible to avoid the oil intrusion from the interior of the engine 10 to the first introduction passage 43 or the second introduction passage 44, the second oil separator 47 may be omitted.
As shown in
As shown in
As shown in
The blow-by gas processing apparatuses shown in
The supercharger 24 provided in the engine 10 is not limited to the exhaust-driven type, but may be structured as an engine driven type. Further, the intake passage 20 to the intercooler 29 may be omitted. The blow-by gas processing apparatus in accordance with the present invention may be applied to the engine 10 in these cases.
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