JP2006104983A - Blow-by gas reducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance and highly reliable PCV device by restraining sludging of an oil component. <P>SOLUTION: This blow-by gas reducing device has an intake system 10 for introducing an air-fuel mixture of air and fuel to a combustion chamber 26 of an engine 20, first or third PCV passages 16, 18 and 32 for reducing blow-by gas leaking out of the combustion chamber 26 to the intake system 10, and an oil separator for separating and removing the oil component included in the blow-by gas. The third PCV passage 32 is connected to a storage tank 36a via a switching control valve 33 and a branch passage 34. When stopping the engine 20, the blow-by gas remaining in the oil separator is forcibly sucked by negative pressure stored in the storage tank 36a, and fresh air is introduced into the oil separator via the second PCV passage 18. When resuming operation of the engine, the blow-by gas stored in the storage tank 36a is reduced to the intake system 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a blow-by gas reduction device for an internal combustion engine, generally called a PCV (Positive Crankcase Ventilation) device.

  In an internal combustion engine (engine) mounted on a vehicle or the like, a mixture of fuel and air is burned in a cylinder, and power is obtained by reciprocating a piston based on energy generated by the combustion. Normally, in this type of engine, a PCV device is installed in which an unburned air-fuel mixture (blow-by gas) is sent again through the intake system into the combustion chamber of the engine and recombusted without being released into the atmosphere.

  8 and 9 are schematic cross-sectional views for explaining the configuration and operation of a general PCV device. In FIG. 8, the flow of fresh air and blow-by gas when the engine is in a light load state is indicated by arrows, and in FIG. 9, fresh air and blow-by gas when the engine is in a high load state. The flow is shown by arrows.

  As shown in FIGS. 8 and 9, the engine 20 mainly includes a cylinder 21, a piston 22, a crankcase 23, and a cylinder head 23a. The blow-by gas is a mixed gas that leaks into the crankcase 23 from the gap between the piston ring and the cylinder 21, and since this blow-by gas contains a large amount of hydrocarbons and is strongly acidic, If it is too much, it will cause deterioration of engine oil and rust inside the engine 20. Moreover, since hydrocarbons are contained, it is not good for the environment to open to the atmosphere as it is. Therefore, the blow-by gas reduces the negative pressure of the intake system 10 through the first PCV path 16 at a light load (see FIG. 8), and through the first PCV path 16 and the second PCV path 18 at a high load (see FIG. 9). It is forcibly returned to the intake system 10 by use.

  The intake system 10 is mainly provided with an air cleaner 11 in which a filter 12 is disposed, a throttle valve 13, and a surge tank 14. The intake air cleaned by the air cleaner 11 is supplied to the surge tank 14 after the amount of intake air supplied to the engine 20 is adjusted by the throttle valve 13. The intake air supplied to the surge tank 14 is supplied from the intake valve 24 to the combustion chamber 26 inside the engine 20 through the intake port 15. Fuel is combusted by the supplied intake air, and combustion gas is discharged to the outside of the engine 20 through the exhaust valve 25 and the exhaust port 27.

  The blow-by gas generated in the gap between the piston ring and the cylinder 21 passes through the crankcase 23 and the cylinder head 23a, passes through the first PCV path 16 at a light load, and passes through the first PCV path 16 and the second PCV path 18 at a high load. Through the intake port 15. A PCV valve 17 is provided in the first PCV path 16. The PCV valve 17 is a flow rate regulating valve that regulates the flow rate with the strength of the negative pressure of the intake system 10. That is, as shown in FIGS. 8 and 9, the flow rate of the PCV path 16 is adjusted by the PCV valve 17 to reduce the blow-by gas downstream of the throttle valve 13. Further, the second PCV path 18 returns blow-by gas to the downstream side of the air cleaner 11 and the upstream side of the throttle valve 13 when the engine 20 is under a high load.

  In such a PCV device, blow-by gas passes through the crank chamber and the cam chamber. Therefore, a large amount of engine oil and oil mist are contained in blow-by gas. The blow-by gas containing a large amount of the oil component is separated from the oil component by an oil separator formed in a head cover that is usually attached to the upper part of the cylinder head. The separated oil component is returned to the crank chamber and the cam chamber.

  However, when the engine is stopped, blow-by gas containing a large amount of engine oil and oil mist stays in the head cover, so that engine oil droplets are generated on the inner wall surface of the head cover. There was a problem of sludge formation. Since the oil component sludge is accumulated in the head cover, it is a major cause of a decrease in the performance of the PCV device.

Examples of documents related to the PCV device described above include Japanese Patent Application Laid-Open No. 5-71423 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2003-120246 (Patent Document 2).
JP-A-5-71423 JP 2003-120246 A

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-performance and high-reliability PCV device by suppressing sludge formation of oil components.

  A blow-by gas reduction apparatus according to the present invention includes an intake system for introducing an air-fuel mixture into a combustion chamber of an internal combustion engine, a PCV path for reducing blow-by gas leaking from the combustion chamber to the intake system, and a blow-by gas. An oil separator that separates and removes oil components contained therein, and the blow-by gas remaining in the oil separator is forcibly sucked into the oil separator after the internal combustion engine is stopped. A forced ventilation means is provided that introduces fresh air to ventilate the oil separator and reduces the sucked-by gas to the intake system when the internal combustion engine is restarted.

  With this configuration, when the internal combustion engine is stopped, the oil separator is ventilated and filled with fresh air, so that oil components are prevented from adhering as oil droplets inside the oil separator. As a result, it is possible to suppress the oil from becoming sludge inside the oil separator, and a high-performance and highly reliable PVC device can be obtained. In addition, blow-by gas that is forcibly taken in when the internal combustion engine is stopped is reduced to the intake system when the operation of the internal combustion engine is resumed, so that no pollutants are released into the atmosphere and the environment is not polluted. .

  In the blowby gas reduction apparatus according to the present invention, the forced ventilation means includes a branch path having one end connected to the PCV path and a storage tank connected to the other end of the branch path. Preferably it is.

  Thus, by providing a branch path in the PCV path and a storage tank for storing blow-by gas in the branch path, the oil separator is forcibly ventilated to fresh air when the internal combustion engine is stopped, and the internal combustion engine Forced ventilation means for reducing the stored blowby gas to the intake system when the engine is restarted can be manufactured easily and inexpensively.

  In the blow-by gas reduction device according to the present invention, the forced ventilation means increases the volume of the storage tank after the internal combustion engine is stopped, and the storage tank during operation of the internal combustion engine. It is preferable to include volume variable means for reducing the volume of the volume.

  By configuring in this manner, the volume increasing means operates after the internal combustion engine is stopped, so that blow-by gas can be forcibly sucked into the storage tank by the negative pressure accompanying the increase in volume, By operating the volume variable means during operation of the internal combustion engine, the volume of the storage tank is maintained in a reduced state, and blow-by gas is prevented from entering and exiting the storage tank. For this reason, after the internal combustion engine is stopped, a strong negative pressure can be generated in the storage tank, so that the blow-by gas can be reliably sucked. Therefore, it can be set as the blowby gas reduction apparatus excellent in ventilation performance by setting it as this structure.

  According to the present invention, since it is possible to suppress sludge formation of the oil component in the oil separator, a high-performance and highly reliable PCV device can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
1 and 2 are schematic cross-sectional views for explaining the configuration and operation of the PCV device according to Embodiment 1 of the present invention. In FIG. 1, the flow of blow-by gas and fresh air when the engine is stopped (immediately after the engine is stopped) is indicated by arrows, and in FIG. 2, the blow-by gas when engine operation is resumed (immediately after engine operation is resumed) The flow of fresh air is indicated by arrows. Parts similar to those of the conventional PCV device shown in FIGS. 8 and 9 are given the same reference numerals in the drawings, and description thereof will not be repeated here.

  As shown in FIGS. 1 and 2, in the engine 20 including the PCV device according to the present embodiment, a head cover 31 is attached on the cylinder head 23 a, and an oil separator is formed in the head cover 31. The oil separator is provided in the middle of the PCV path from the combustion chamber 26 to the intake system 10 and communicates with the crank chamber and the cam chamber of the engine 20. Blow-by gas is introduced into the oil separator from below. The head cover 31 is connected to three PCV paths, a first PCV path 16, a second PCV path 18, and a third PCV path 32, and each PCV path 16, 18, 32 communicates with an oil separator.

  The other end of the first PCV path 16 is connected to a portion of the intake system 10 located downstream of the throttle valve 13. The throttle valve 13 is means for appropriately adjusting the amount of intake air supplied to the engine 20 according to the load state of the engine 20. A PCV valve 17 is disposed in the first PCV path 16. The PCV valve 17 is a flow rate adjusting means that regulates the flow rate of blow-by gas by the strength of the negative pressure of the intake system 10.

  The other end of the second PCV path 18 is connected to the intake system 10 at a portion located on the upstream side of the throttle valve 13 and a portion located on the downstream side of the air cleaner 11. The second PCV path 18 introduces fresh air into the oil separator or introduces blow-by gas into the intake system 10 according to the pressure difference between the intake system 10 and the oil separator.

  The other end of the third PCV path 32 is connected to a portion of the intake system 10 located on the downstream side of the throttle valve 13, and a branch path 34 is connected via a switching control valve 33 provided in the middle of the third PCV path 32. It is connected to the. The third PCV path 32 has an upstream portion 32 a that connects the oil separator and the switching control valve 33, and a downstream portion 32 b that connects the switching control valve 33 and the intake system 10. A storage tank 36 a capable of storing blow-by gas when the engine is stopped is connected to the other end of the branch path 34.

  The switching control valve 33 is a three-way valve that operates in conjunction with a pressure regulator 35 that operates based on a pressure difference between the intake system 10 and the atmosphere, and communicates the upstream portion 32 a of the third PCV path 32 and the branch path 34. Or a means for switching between the branch path 34 and the downstream portion 32b of the third PCV path 32. The switching control valve 33 and the pressure regulator 35 shown in FIGS. 1 and 2 are configured by combining an elastic body such as a spring and a mechanical element such as a valve body that closes or opens a path. The path switching means is configured to mechanically switch the path in accordance with the pressure difference between the intake system 10 and the atmosphere.

  In the PCV device configured as described above, the following operation is performed when the engine is stopped (immediately after the engine is stopped). First, during engine operation, the upstream portion 32a of the third PCV path 32 and the branch path 34 are maintained in a closed state by the action of the pressure regulator 35 and the switching control valve 33. The downstream portion 32b of the 3PCV path 32 is maintained in communication. In this situation, the storage tank 36a communicates with the intake system 10 via the branch path 34 and the downstream portion 32b of the third PCV path 32, so the internal pressure is maintained at a relatively low pressure. On the other hand, since the upstream portion 32a of the third PCV path 32 communicates with the oil separator, the internal pressure is maintained at a relatively high pressure.

  In this state, when the engine 20 is stopped, the pressure in the surge tank 14 increases as the pressure inside the intake system 10 returns to atmospheric pressure. At this time, due to the action of the pressure regulator 35 and the switching control valve 33, the branch path 34 and the downstream portion 32b of the third PCV path 32 are closed by the valve body, and the upstream of the third PCV path 32 is accompanied by the movement of the valve body. The side portion 32a and the branch path 34 are opened and communicated. Thereby, the blow-by gas in the oil separator in a high pressure state is sucked by the negative pressure stored in the storage tank 36 a and passes through the upstream portion 32 a of the third PCV path 32, the switching control valve 33 and the branch path 34. It is introduced into the storage tank 36a. Accordingly, a negative pressure is generated inside the oil separator, so that fresh air is introduced into the oil separator via the second PCV path 18. Through the above operation, the blow-by gas remaining in the oil separator is forcibly exhausted into the storage tank 36a. As a result, fresh air is introduced into the oil separator, and ventilation in the oil separator is realized ( (See FIG. 1).

  In the PCV device having the above-described configuration, the following operation is performed when engine operation is resumed (immediately after engine operation is resumed). First, when the engine 20 operates, a negative pressure is generated in the intake system 10. Along with this, the valve body of the switching control valve 33 is moved by the action of the pressure regulator 35, the upstream portion 32a of the third PCV path 32 and the branch path 34 are closed, and the branch path 34 and the third PCV path 32 are closed. The downstream portion 32b is in communication with the downstream portion 32b. As a result, the blow-by gas stored in the storage tank 36 a is introduced into the intake system 10 via the downstream portion 32 b of the third PCV path 32. The blow-by gas introduced into the intake system 10 is supplied into the combustion chamber 26 and used for the combustion operation of the engine 20. Further, the blow-by gas stored in the storage tank 36a is introduced into the intake system 10, whereby a negative pressure is gradually accumulated in the storage tank 36a (see FIG. 2).

  In the PCV device in the present embodiment described above, the second PCV path 18 which is a path for introducing fresh air into the oil separator and the third PCV which is a path for exhausting blow-by gas from the oil separator. It comprises a path 32, a switching control valve 33 and a branch path 34, a storage tank 36a which is a storage part for storing blow-by gas exhausted from the oil separator, and a pressure regulator 35 for operating the switching control valve 33. The forced ventilation means forcibly sucks the blow-by gas remaining in the oil separator when the engine 20 is stopped, introduces fresh air into the oil separator, and allows ventilation in the oil separator. Suction blow-by after engine restart The scan becomes possible to reduce the intake system 10. For this reason, the oil separator is filled with fresh air when the engine is stopped, and the oil component is prevented from becoming sludge in the oil separator. As a result, high performance and high reliability PVC It can be a device. Further, the blow-by gas that is forcibly sucked when the engine is stopped is reduced to the intake system 10 when the operation of the engine is resumed, so that no pollutants are released into the atmosphere and the environment is not polluted. Furthermore, the forced ventilation means can be configured with a simple configuration in which the branch path 34 is provided in the PCV path and the storage tank 36a for storing the blow-by gas is provided in the branch path 34. A reliable PCV device can be manufactured.

(Embodiment 2)
3 and 4 are schematic cross-sectional views for explaining the configuration and operation of the PCV device according to Embodiment 2 of the present invention. In FIG. 3, the flow of blow-by gas and fresh air when the engine is stopped (immediately after the engine is stopped) is indicated by arrows. In FIG. 4, The flow of fresh air is indicated by arrows. In addition, the same code | symbol is attached | subjected in the figure about the part similar to the PCV apparatus in the above-mentioned Embodiment 1, and the description is not repeated here.

  In the PCV device according to the first embodiment described above, the path switching means including the switching control valve 33 and the pressure regulator 35 is employed as the path switching means for switching the communication state between the third PCV path 32 and the branch path 34. Yes. However, depending on the operating condition of the engine immediately before the operation is stopped, it may be assumed that the above pressure difference cannot be sufficiently ensured. Therefore, in the PCV device in the present embodiment, the forced ventilation means is improved so that the forced ventilation of the blow-by gas in the oil separator can be surely performed even in such a case.

  As shown in FIG. 3, the PCV device in the present embodiment includes a bellows type storage tank 36b in place of the storage tank 36a of the PCV device in the first embodiment. A shaft member 37 provided with a wedge-shaped notch is attached to the bellows-type storage tank 36b. The shaft member 37 is sandwiched between a pair of springs in the expansion / contraction direction of the bellows-type storage tank 36b. ing. The PCV device according to the present embodiment further includes a lock member 38 that locks the movement of the shaft member 37 described above. The lock member 38 is configured to be interlocked with the operation of the pressure regulator 35, and a wedge-shaped portion provided at the tip of the lock member 38 engages with a wedge-shaped notch provided in the shaft member 37, whereby the shaft member 37 is locked immovably.

  In the PCV device configured as described above, the following operation is performed when the engine is stopped (immediately after the engine is stopped). First, during engine operation, the upstream portion 32a of the third PCV path 32 and the branch path 34 are maintained in a closed state by the action of the pressure regulator 35 and the switching control valve 33. The downstream portion 32b of the 3PCV path 32 is maintained in communication. In this situation, the bellows type storage tank 36b communicates with the intake system 10 via the branch path 34 and the downstream portion 32b of the third PCV path 32, so that the internal pressure is maintained at a relatively low pressure. Yes. Further, since the shaft member 37 is locked so as not to move by the lock member 38 due to the action of the pressure regulator 35, the bellows type storage tank 36b connected to the shaft member 37 is also limited in its expansion. It is maintained in a contracted state where the volume is minimized. On the other hand, since the upstream portion 32a of the third PCV path 32 communicates with the oil separator, the internal pressure is maintained at a relatively high pressure.

  In this state, when the engine 20 is stopped, the pressure in the surge tank 14 increases as the pressure inside the intake system 10 returns to atmospheric pressure. At this time, due to the action of the pressure regulator 35 and the switching control valve 33, the branch path 34 and the downstream portion 32b of the third PCV path 32 are blocked by the valve body, and on the contrary, the upstream portion 32a of the third PCV path 32. And the branch path 34 are opened and communicated. At the same time, the lock member 38 is moved by the action of the pressure regulator 35 and the lock of the shaft member 37 by the lock member 38 is released. When the lock is released, the shaft member 37 is lifted by the action of the spring that pinches the shaft member 37, the bellows type storage tank 36b is forcibly expanded, and an expansion state is reached in which the volume is maximized. Along with the expansion of the bellows-type storage tank 36b, a strong negative pressure is generated in the bellows-type storage tank 36b. Is strongly forcibly sucked into the bellows type storage tank 36 b via the upstream portion 32 a, the switching control valve 33 and the branch path 34. Accordingly, a negative pressure is generated inside the oil separator, so that fresh air is introduced into the oil separator via the second PCV path 18. Through the above operation, blow-by gas remaining in the oil separator is forcibly exhausted into the bellows type storage tank 36b. As a result, fresh air is introduced into the oil separator, and ventilation in the oil separator is performed. Realize (see FIG. 3).

  In the PCV device having the above-described configuration, the following operation is performed when engine operation is resumed (immediately after engine operation is resumed). First, when the engine 20 operates, a negative pressure is generated in the intake system 10. Along with this, the valve body of the switching control valve 33 is moved by the action of the pressure regulator 35, the upstream portion 32a of the third PCV path 32 and the branch path 34 are closed, and the branch path 34 and the third PCV path 32 are closed. The downstream portion 32b is in communication with the downstream portion 32b. As a result, the blow-by gas stored in the bellows type storage tank 36 b is introduced into the intake system 10 via the downstream portion 32 b of the third PCV path 32. The blow-by gas introduced into the intake system 10 is supplied into the combustion chamber 26 and used for the combustion operation of the engine 20. In addition, when the blow-by gas stored in the bellows type storage tank 36b is introduced into the intake system 10, the bellows type storage tank 36b contracts and eventually reaches a contracted state in which the volume is minimized. In this state, the shaft member 37 is locked again by the lock member 38 moved by the action of the pressure regulator 35, and the bellows type storage tank 36b is maintained in the contracted state (see FIG. 4).

  In the PCV device in the present embodiment described above, unlike the PCV device in the first embodiment described above, the volume of the bellows type storage tank 36b is increased as the forced ventilation means after the engine 20 is stopped. It further includes a shaft member 37 as volume increasing means and a lock member 38 as volume changing means for reducing the volume of the bellows type storage tank 36b during operation of the engine 20 and maintaining the reduced state. By configuring in this way, the blow-by gas in the oil separator can be reliably sucked by expanding and contracting the bellows type storage tank 36b, so that the blow-by gas reduction device having excellent ventilation performance is provided. Can do.

(Embodiment 3)
In the first and second embodiments described above, the case where the configuration in which the communication state between the third PCV path and the branch path is mechanically switched using a pressure regulator has been described as an example. Of course, it is also possible to perform the switching of the routes. As the path switching means for electrically switching the path, for example, an electromagnetic valve or a three-way valve driven by a driving means such as a motor can be used. In the following, some embodiments of the control method of the PCV apparatus when these electrical path switching means are used will be described with reference to flowcharts.

  FIG. 5 is a flowchart showing a first example of the control method of the PCV apparatus in the third embodiment of the present invention. The present embodiment shows a case where it is configured to detect whether there is a negative pressure in the intake system using a pressure sensor or the like and to control the electrical path switching means based on this detection information. . The configuration of the PCV path and the structure of the storage tank in this example are the same as those in the first embodiment, and only the path switching means is an electrical path switching means different from that in the first embodiment. Has been replaced.

  As shown in FIG. 5, in the PCV apparatus in the first embodiment, when the engine 20 is started in step 101 (S101), a signal for turning on the switching control valve in step 102 (S102) is derived. In step 103 (S103), when the switching control valve is turned ON, the upstream part 32a and the branch path 34 of the third PCV path 32 are closed and the branch path 34 and the downstream part 32b of the third PCV path 32 are closed. And communicated with each other. In this state, blow-by gas stored in the storage tank 36a is introduced into the intake system 10, and negative pressure is accumulated in the storage tank 36a.

  In step 104 (S104), it is detected whether or not there is a negative pressure in the intake system 10. If there is, the process returns to step 102 and the above operation is repeated. If not, the process proceeds to step 105 (S105). Then, a signal for turning off the switching control valve is derived. As a result, when the switching control valve is turned OFF in step 106 (S106), the upstream part 32a and the branch path 34 of the third PCV path 32 are opened, and the downstream part of the branch path 34 and the third PCV path 32 is opened. 32b is closed. Accordingly, blow-by gas in the oil separator is sucked into the storage tank 36a, and the oil separator is ventilated and filled with fresh air. In step 107 (S107), the engine is stopped.

  By going through the above flow, forced ventilation in the oil separator can be realized when the engine is stopped. Even in such a configuration, a high-performance and highly reliable PCV device can be obtained.

  FIG. 6 is a flowchart showing a second example of the control method of the PCV apparatus in the third embodiment of the present invention. This embodiment shows a case where it is detected whether or not there is an engine ignition signal, and the electric path switching means is controlled based on this detection information. The configuration of the PCV path and the structure of the storage tank in this example are the same as those in the first embodiment, and only the path switching means is an electrical path switching means different from that in the first embodiment. Has been replaced.

  As shown in FIG. 6, in the PCV apparatus in the second embodiment, it is detected in step 201 (S201) whether or not there is an ignition signal of the engine 20, and if so, the engine 20 is started in step 202 (S202). Let After the engine 20 is started, in step 203 (S203), the upstream portion 32a of the third PCV path 32 and the branch path 34 are closed, and the branch path 34 and the downstream portion 32b of the third PCV path 32 are communicated. In this state, blow-by gas stored in the storage tank 36a is introduced into the intake system 10, and negative pressure is accumulated in the storage tank 36a.

  Then, in step 204 (S204), it is detected again whether or not there is an ignition signal of the engine 20, and if there is, the operation returns to step 203 and the above operation is repeated, and if not, the routine proceeds to step 205 (S205). The upstream part 32 a and the branch path 34 of the third PCV path 32 are opened, and the branch path 34 and the downstream part 32 b of the third PCV path 32 are closed. Thereby, the blow-by gas in the oil separator is sucked into the storage tank 36a, and the oil separator is ventilated and filled with fresh air. In step 206 (S206), the engine 20 is stopped.

  By passing through the above flow, forced ventilation in the oil separator can be realized when the engine is stopped even when an electrical control method is used. Even in such a configuration, a high-performance and highly reliable PCV device can be obtained.

  FIG. 7 is a flowchart showing a third example of the control method of the PCV apparatus in the third embodiment of the present invention. The configuration of the PCV path and the structure of the storage tank in this example are the same as those in the second embodiment, and only the path switching means is an electrical path switching means that is different from the second embodiment. Has been replaced.

  As shown in FIG. 7, in the PCV apparatus in the third embodiment, it is detected in step 301 (S301) whether or not there is an ignition signal of the engine 20, and if so, the engine 20 is started in step 302 (S302). Let me. After the engine 20 is started, in step 303 (S303), it is detected whether or not the rotational speed of the engine 20 is equal to or higher than the idling rotational speed. If it is equal to or higher than the idling speed, in step 304 (S304), the upstream part 32a and the branch path 34 of the third PCV path 32 are closed and the branch path 34 and the downstream part 32b of the third PCV path 32 are communicated. Let me. In this state, blow-by gas stored in the bellows type storage tank 36b is introduced into the intake system 10, and negative pressure is accumulated in the bellows type storage tank 36b.

  In step 305 (S305), it is detected again whether or not there is an ignition signal of the engine 20. If there is, the process returns to step 304 and the above operation is repeated. If not, the process proceeds to step 306 (S306). The upstream part 32a and the branch path 34 of the third PCV path 32 are opened, and the branch path 34 and the downstream part 32b of the third PCV path 32 are closed. In step 307 (S307), the engine 20 is stopped.

  Next, in step 308 (S308), the volume of the bellows type storage tank 36b is forcibly expanded, and this state is maintained until the bellows type storage tank 36b is sufficiently expanded in step 309 (S309). As a result, the blow-by gas in the oil separator is sucked into the bellows type storage tank 36b, and the oil separator is ventilated and filled with fresh air. Then, after confirming that a sufficient holding time is secured, the expansion of the capacity of the bellows type storage tank 36b is stopped in step 310 (S310), and all operations are ended in step 311 (S311).

  By passing through the above flow, forced ventilation in the oil separator can be realized when the engine is stopped even when an electrical control method is used. Even in such a configuration, a high-performance and highly reliable PCV device can be obtained.

  In the above description, the conventional PCV apparatus having the first PCV path 16 and the second PCV path 18 as shown in FIGS. 8 and 9 is described as an example in which a third PCV path 32 is newly provided. Although done, the present invention does not necessarily require three PCV paths. For example, by providing a branch path and a storage tank in the first PCV path 16 and improving the operation of the PCV valve 17, even when the engine is stopped only when two PCV paths are provided. It is possible to achieve forced ventilation.

  Further, the position where the third PCV path is provided is not necessarily limited to the position as described above. For example, the other end of the third PCV path 32 can be connected to the upstream side of the throttle valve.

  In the first to third embodiments described above, the case where only the switching control valve is arranged on the third PCV path has been described as an example. However, on the third PCV path and the branch path as necessary, Various pumps and valve bodies may be provided.

  Thus, the above-described embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic cross section for demonstrating a structure and operation | movement of the PCV apparatus in Embodiment 1 of this invention, and is a figure which shows the flow of blowby gas and fresh air at the time of an engine stop (just after an engine stop). It is a schematic cross section for demonstrating a structure and operation | movement of the PCV apparatus in Embodiment 1 of this invention, and is a figure which shows the flow of blow-by gas and fresh air at the time of engine operation resumption (immediately after engine operation resumption). It is a schematic cross section for demonstrating a structure and operation | movement of the PCV apparatus in Embodiment 2 of this invention, and is a figure which shows the flow of blowby gas and fresh air at the time of an engine stop (just after an engine stop). It is a schematic cross section for demonstrating a structure and operation | movement of the PCV apparatus in Embodiment 2 of this invention, and is a figure which shows the flow of blow-by gas and fresh air at the time of engine operation resumption (immediately after engine operation resumption). It is a flowchart which shows the 1st Example of the control method of the PCV apparatus in Embodiment 3 of this invention. It is a flowchart which shows the 2nd Example of the control method of the PCV apparatus in Embodiment 3 of this invention. It is a flowchart which shows the 3rd Example of the control method of the PCV apparatus in Embodiment 3 of this invention. FIG. 2 is a schematic cross-sectional view for explaining the configuration and operation of a general PCV device, and shows the flow of fresh air and blow-by gas when the engine is in a light load state. FIG. 5 is a schematic cross-sectional view for explaining the configuration and operation of a general PCV device, and shows the flow of fresh air and blow-by gas when the engine is in a high load state.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Intake system, 11 Air cleaner, 12 Filter, 13 Throttle valve, 14 Surge tank, 15 Intake port, 16 1st PCV path, 17 PCV valve, 18 2nd PCV path, 20 Engine, 21 Cylinder, 22 Piston, 23 Crankcase, 23a Cylinder head, 24 Intake valve, 25 Exhaust valve, 26 Combustion chamber, 27 Exhaust port, 31 Head cover, 32 3rd PCV path, 32a Upstream part of 32a (3rd PCV path), 32b Downstream part of 3rd PCV path, 33 Switching control valve, 34 branch path, 35 pressure regulator, 36a storage tank, 36b (accordion type) storage tank, 37 shaft member, 38 lock member.

Claims (3)

An intake system for introducing an air-fuel mixture into the combustion chamber of the internal combustion engine;
A PCV path for reducing blow-by gas leaking from the combustion chamber to the intake system;
An oil separator provided in the PCV path for separating and removing oil components contained in the blow-by gas;
After the internal combustion engine is stopped, the blow-by gas remaining in the oil separator is forcibly sucked, fresh air is introduced into the oil separator to ventilate the oil separator, and the internal combustion engine is operated. A blow-by gas reduction device comprising forced ventilation means for reducing the sucked-by blow-by gas to the intake system when restarting.   The blow-by gas reduction device according to claim 1, wherein the forced ventilation means includes a branch path having one end connected to the PCV path and a storage tank connected to the other end of the branch path.   The forced ventilation means includes a volume increasing means for increasing the volume of the storage tank after the internal combustion engine is stopped, and a volume variable means for reducing the volume of the storage tank during operation of the internal combustion engine. The blowby gas reduction apparatus according to claim 2.

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