Patent Application
20190316500
The following description relates to a PCV valve coupling structure.
The internal combustion engine installed in a vehicle or the like includes a blow-by gas recirculation device that causes blow-by gas in the internal combustion engine to flow back to the intake system. The blow-by gas recirculation device includes a blow-by gas passage through which blow-by gas flows to the intake system of the internal combustion engine and a PCV valve used to adjust the gas flow area of the blow-by gas passage. The PCV valve is arranged halfway on the blow-by gas passage. For example, the PCV valve is coupled to the internal combustion engine as described in Japanese Laid-Open Patent Publication No. 2011-236854. More specifically, the PCV valve is fastened to the internal combustion engine by fastening bolts to limit removal of the PCV valve from the internal combustion engine.
As described in the above-mentioned publication, when the PCV valve is fastened to the internal combustion engine by bolts, the PCV valve does not easily come off from the internal combustion engine. However, a user may remove the PCV valve from the internal combustion engine by unfastening the bolts. In this case, blow-by gas in the internal combustion engine will be emitted into the atmosphere through a portion of the internal combustion engine coupled to the PCV valve.
It is an objective of the present invention to provide a PCV valve coupling structure that prevents the emission of blow-by gas into the atmosphere caused when the PCV valve is removed from the internal combustion engine.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
A first aspect of a PCV valve coupling structure that solves the above-described problem is employed in a PCV valve used to adjust a gas flow area of a blow-by gas passage through which blow-by gas in an internal combustion engine flows to an intake system of the internal combustion engine, the PCV valve coupling structure coupling the PCV valve to the internal combustion engine. In the PCV valve coupling structure, the PCV valve is coupled to the internal combustion engine in a non-removable manner.
A second aspect of a PCV valve coupling structure that solves the above-described problem is employed in a PCV valve used to adjust a gas flow area of a blow-by gas passage through which blow-by gas in an internal combustion engine flows to an intake system of the internal combustion engine, the PCV valve coupling structure coupling the PCV valve to the internal combustion engine. The PCV valve coupling structure includes a coupling member that is separate from the PCV valve and used to couple the PCV valve to the internal combustion engine in a non-removable manner.
Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience.
This description provides a comprehensive understanding of the methods, apparatuses, and/or systems described. Modifications and equivalents of the methods, apparatuses, and/or systems described are apparent to one of ordinary skill in the art. Sequences of operations are exemplary, and may be changed as apparent to one of ordinary skill in the art, with the exception of operations necessarily occurring in a certain order. Descriptions of functions and constructions that are well known to one of ordinary skill in the art may be omitted.
Exemplary embodiments may have different forms, and are not limited to the examples described. However, the examples described are thorough and complete, and convey the full scope of the disclosure to one of ordinary skill in the art.
A PCV valve coupling structure according to a first embodiment will now be described with reference to
As shown in
In the internal combustion engine, when fuel is burned in a combustion chamber, blow-by gas leaks from the combustion chamber into the crankcase 3. Thus, the internal combustion engine includes a blow-by gas recirculation device that causes gas (including blow-by gas) in the crankcase 3 to flow back to the intake system (intake passage 5) of the internal combustion engine. The blow-by gas recirculation device includes a blow-by gas passage 6 through which blow-by gas in the crankcase 3 flows to the intake passage 5 and a PCV valve 7 used to adjust the gas flow area of the blow-by gas passage 6.
The PCV valve 7 is coupled to the head cover 4. One end of a hose 8 is connected to the PCV valve 7, and the other end of the hose 8 is connected to the intake passage 5 of the internal combustion engine. The blow-by gas passage 6 communicates with the crankcase 3. The blow-by gas passage 6 extends through the cylinder block 1, the cylinder head 2, the head cover 4, the PCV valve 7, and the hose 8 to communicate with the intake passage 5.
Thus, the PCV valve 7 is arranged halfway on the blow-by gas passage 6. Adjusting the gas flow area of the blow-by gas passage 6 with the PCV valve 7 changes the flow rate of gas flowing from the crankcase 3 through the blow-by gas passage 6 to the intake passage 5.
The structure for coupling the PCV valve 7 to the head cover 4 will now be described.
As shown in
The head cover 4 includes a coupling hole 13 to which the PCV valve 7 is coupled. The inner circumferential surface of the coupling hole 13 includes an internal thread 13a with which the external thread 10 of the housing 9 of the PCV valve 7 is engaged. When the external thread 10 of the housing 9 is engaged with the internal thread 13a of the coupling hole 13, the flange 11 of the housing 9 is located on the outer side of the head cover 4 (upper side in
The end surface of the housing 9 located closer to the external thread 10 (lower end surface in
A plate-shaped coupling member 18, which is made of plastic or metal, is arranged on the upper side of the flange 11 of the PCV valve 7. The coupling member 18 is separate from the PCV valve 7. The coupling member 18 is used to couple the PCV valve 7 to the head cover 4. The coupling member 18 is in contact with the flange 11 of the PCV valve 7. The coupling member 18 has a through-hole 19. The protrusion 17 of the PCV valve 7 extends vertically through the through-hole 19. Further, a fixation hole 20 is formed beside the through-hole 19 of the coupling member 18. A deformation part 21 protruding upward from the head cover 4 extends through the fixation hole 20. From a state in which the deformation part 21 extends through the fixation hole 20 as shown by the long dashed double-short dashed line in
As a result, the PCV valve 7 is coupled to the head cover 4 of the internal combustion engine by the coupling member 18 in a non-removable manner. More specifically, the PCV valve 7 is pressed down toward the coupling hole 13 by the coupling member 18, thereby fixing the PCV valve 7 to the head cover 4 to prevent the removal of the PCV valve 7 from the coupling hole 13. Additionally, after plastic deformation of the deformation part 21 causes the coupling member 18 to be coupled to the head cover 4 as described above, the PCV valve 7 cannot be removed from the head cover 4.
The advantages of the coupling structure for the PCV valve 7 according to the first embodiment will now be described.
(1) The PCV valve 7 is coupled to the head cover 4 of the internal combustion engine by the coupling member 18 in a non-removable manner. This prevents the PCV valve 7 from coming off from the head cover 4 and also prevents a user from removing the PCV valve 7 from the head cover 4. Thus, the removal of the PCV valve 7 from the head cover 4 of the internal combustion engine is prevented. Consequently, the emission of blow-by gas into the atmosphere caused by the removal of the PCV valve 7 is prevented.
(2) To arrange blow-by gas recirculation devices in various types of internal combustion engines, it is desired that the same PCV valve 7 be used to achieve cost reduction. However, the internal combustion engines may have different types of relationships between the coupling hole 13 and the deformation part 21 of the head cover 4. In this case, multiple types of coupling members 18 corresponding to the positional relationships between the coupling hole 13 and the deformation part 21 in the internal combustion engines are prepared. This allows the PCV valve 7 to be coupled to the head cover 4 in a non-removable manner without modifying the PCV valve 7. Thus, the same PCV valve 7 can be used in each internal combustion engine.
A PCV valve coupling structure according to a second embodiment will now be described with reference to
In the internal combustion engine in which the PCV valve 7 is employed, a separator configured to separate liquid such as oil from blow-by gas is arranged halfway on the blow-by gas passage 6. The PCV valve 7 according to the second embodiment is used to adjust the gas flow area of a portion of the blow-by gas passage 6 corresponding to the separator.
As shown in
The flow rate adjustment unit 32 of the PCV valve 7 includes a tubular housing 32a. The housing 32a is inserted into a coupling hole 35 formed in the separator 31. A communication hole 34 is formed in the end of the housing 32a on the opposite side from the end of the housing 32a located closer to the pipe connection unit 33. The communication hole 34 communicates with the inside of the separator 31. In addition, the outer circumferential surface of the housing 32a includes a flange 32b. The flange 32b has a larger diameter than the coupling hole 35 of the separator 31 and is in contact with a portion of the outer surface of the separator 31 located around the opening of the coupling hole 35. Additionally, the seal ring 12 is arranged at a portion corresponding to the outer circumferential surface of the housing 32a and the inner circumferential surface of the coupling hole 35. The seal ring 12 is in contact with the outer circumferential surface of the housing 32a and the inner circumferential surface of the coupling hole 35 to seal a part between the outer circumferential surface of the housing 32a and the inner circumferential surface of the coupling hole 35.
The housing 32a incorporates a tubular movable member 36, a spring 37, and a ring 38. The movable member 36 extends on the same axis as the housing 32a. The spring 37 biases the movable member 36 toward the communication hole 34. The ring 38 is fitted to the inner circumferential surface of the opening of the housing 32a located closer to the pipe connection unit 33. In addition, the pipe connection unit 33 includes a tubular housing 33a. The housing 33a is fitted to the opening of the housing 32a of the flow rate adjustment unit 32 located closer to the pipe connection unit 33. As a result, the ring 38 is held between the housing 33a of the pipe connection unit 33 and the housing 32a of the flow rate adjustment unit 32. The inside of the housing 33a communicates with the inside of the housing 32a of the flow rate adjustment unit 32 through the ring 38. Further, a flange 33c is formed at the end of the housing 33a of the pipe connection unit 33 located closer to the flow rate adjustment unit 32. A protrusion 33b is formed at the end of the housing 33a located on the opposite side from the flange 33c. The hose 8 is fitted to the outer circumferential surface of the protrusion 33b.
The movable member 36 in the housing 32a of the flow rate adjustment unit 32 is biased by a biasing force of the spring 37 to a position where the communication hole 34 of the housing 32a is closed. Further, the end of the movable member 36 located closer to the pipe connection unit 33 is inserted into the ring 38. The outer circumferential surface of the movable member 36 has a diameter that is smaller than the inner circumferential surface of the ring 38 and increases toward the communication hole 34. Intake negative pressure of the internal combustion engine acts in the hose 8 and the housing 33a of the pipe connection unit 33. Thus, the intake negative pressure causes the movable member 36 to move toward the pipe connection unit 33 against the biasing force of the spring 37. The movement of the movable member 36 toward the pipe connection unit 33 opens the communication hole 34 of the housing 32a, which has been closed by the movable member 36. When the communication hole 34 opens, blow-by gas in the separator 31 of the internal combustion engine flows to the hose 8 through the PCV valve 7 (flow rate adjustment unit 32 and pipe connection unit 33).
The flow rate of the blow-by gas varies depending on the position of the movable member 36 relative to the ring 38. That is, during a low-load operation of the internal combustion engine, the movable member 36 is moved toward the pipe connection unit 33 to the largest extent. The large-diameter portion of the outer circumferential surface of the movable member 36 is opposed to the inner circumferential surface of the ring 38. This reduces the gas flow area between the outer circumferential surface of the movable member 36 and the inner circumferential surface of the ring 38 and consequently reduces the flow rate of blow-by gas that passes through the PCV valve 7. As the engine load becomes higher, the movable member 36 moves to a smaller extent against the biasing force of the spring 27 toward the pipe connection unit 33. As a result, as the engine load becomes higher, the gas flow area between the outer circumferential surface of the movable member 36 and the inner circumferential surface of the ring 38 increases. This consequently increases the flow rate of blow-by gas that passes through the PCV valve 7. A spring 44 is arranged in the housing 33a of the pipe connection unit 33 to restrict excessive movement of the movable member 36 toward the pipe connection unit 33.
The structure for coupling the PCV valve 7 to the separator 31 will now be described.
As shown in
The contact part 41 of the coupling member 39 is in contact with the flange 33c of the housing 33a of the pipe connection unit 33 while holding the protrusion 33b of the pipe connection unit 33 in the PCV valve 7 from the opposite sides of the protrusion 33b in the radial direction of the protrusion 33b. As shown in
The advantages of the coupling structure for the PCV valve 7 according to the second embodiment will now be described. The second embodiment has the following advantages in addition to advantages (1) and (2) of the first embodiment.
(3) When external impact or the like is applied to cause the part (hose 8) of the blow-by gas passage 6 connecting the intake passage 5 and the PCV valve 7 in the internal combustion engine to be removed from the PCV valve 7 and exposed to the atmosphere, the atmospheric air is drawn into the internal combustion engine through the hose 8. Thus, the intake air amount of the internal combustion engine suddenly increases, thereby stalling the internal combustion engine. When the internal combustion engine is stalled, removal of the hose 8 from the PCV valve 7 can be detected. However, if external impact or the like causes the flow rate adjustment unit 32 to be removed from the internal combustion engine (separator 31) while the hose 8 remains connected to the flow rate adjustment unit 32 through the pipe connection unit 33 of the PCV valve 7, the flow rate adjustment unit 32 limits increases in the intake amount of the atmospheric air that occur when the atmospheric air is drawn into the internal combustion engine through the hose 8. Thus, the intake air amount of the internal combustion engine no longer increases suddenly. This makes it difficult to detect the removal of the hose 8 and the flow rate adjustment unit 32 from the separator 31 by utilizing the stalling of the internal combustion engine, which results from the sudden increases in the intake air amount. In the second embodiment, the removal of the flow rate adjustment unit 32 of the PCV valve 7 from the separator 31 while remaining connected to the hose 8, which results from the application of external impact or the like, is restricted by the coupling member 39. This prevents the occurrence of the above-described problem that detecting the removal of the hose 8 from the separator 31 becomes difficult.
(4) When external impact or the like is applied to cause the part (hose 8) of the blow-by gas passage 6 connecting the intake passage 5 and the PCV valve 7 in the internal combustion engine to be removed from the PCV valve 7 and exposed to the atmosphere, the inner part of the housing 33a of the pipe connection unit 33 in the PCV valve 7 is also exposed to the atmosphere. The biasing force of the spring 37 keeps the movable member 36 at a position where the communication hole 34 is closed. This prevents the emission of blow-by gas from the separator 31 of the internal combustion engine into the atmosphere through the PCV valve 7.
A PCV valve coupling structure according to a third embodiment will now be described with reference to
As shown in
The coupling member 51 has a through-hole 52 and multiple (two in the third embodiment) legs 53 protruding toward the separator 31. The protrusion 33b of the housing 33a of the pipe connection unit 33 in the PCV valve 7 extends through the through-hole 52. As shown in
As shown in
A shear bolt is used for one of the bolt 54 and the bolt 55, more specifically, the bolt 55. Fastening the bolt 55 to the separator 31 causes the head 55a to break away so that the bolt 55 cannot be removed. When the coupling member 51 is coupled to the separator 31 using the bolt 55, the coupling member 51 allows at least the flow rate adjustment unit 32 of the PCV valve 7, more specifically, the pipe connection unit 33 and the flow rate adjustment unit 32, to be coupled to the separator 31 of the internal combustion engine in a non-removable manner.
Accordingly, the third embodiment has the same advantages as the second embodiment.
Modifications
Each of the above-described embodiments may be modified as described below.
In the first embodiment, as shown in
In the first embodiment, as shown in
In the first to third embodiments, the coupling members 18, 39, and 51 do not necessarily have to be made of metal. Instead, for example, the coupling members 18, 39, and 51 may be made of other materials such as plastic. In this case, the coupling members 18, 39, and 51 may be coupled to the plastic head cover 4 and the plastic separator 31 in a non-removable manner through various types of welding such as vibration welding, ultrasonic welding, hot-plate welding, and laser welding.
In the first to third embodiments, the head cover 4 and the separator 31 do not necessarily have to be made of plastic. Instead, for example, the head cover 4 and the separator 31 may be made of metal. In this case, the coupling members 18 and 39 are coupled to the metal head cover 4 and the metal separator 31 in a non-removable manner by, for example, using rivets or performing welding. Further, when the coupling members 18, 39, and 51 are made of plastic, the plastic coupling members 18, 39, and 51 may be coupled to the head cover 4 and the separator 31 in a non-removable manner through, for example, thermal deformation.
In the first to third embodiments, the PCV valve 7 does not necessarily have to be coupled to the head cover 4 or the separator 31. Instead, the PCV valve 7 may be coupled to the cylinder head 2. Alternatively, the PCV valve 7 may be coupled to the cylinder block 1.
In the first to third embodiments, the PCV valve 7 may be coupled to the head cover 4 and the separator 31 in a non-removable manner without using the coupling members 18, 39, and 51. For example, the protrusion amounts of the flanges 11 and 32b may be set to be large so that the flanges 11 and 32b are directly coupled to the head cover 4 and the separator 31 in a non-removable manner.
Various changes in form and details may be made to the examples above without departing from the spirit and scope of the claims and their equivalents. The examples are for the sake of description only, and not for purposes of limitation. Descriptions of features in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if sequences are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined differently, and/or replaced or supplemented by other components or their equivalents. The scope of the disclosure is not defined by the detailed description, but by the claims and their equivalents. All variations within the scope of the claims and their equivalents are included in the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-079216 | Apr 2018 | JP | national |
| 2018-212108 | Nov 2018 | JP | national |
