JP2009293599A - Flow control valve of internal-combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress variation in flow characteristics of a flow control valve caused by deformation of a peripheral edge part of a metering part due to collision between the metering part and a taper part of a valve body. <P>SOLUTION: A PCV valve includes a case 20 having an inlet port 28 and an outlet port 27. The metering part 23 having a circular cross section is formed between the inlet port 28 and outlet port 27. The valve body 30 is stored in the case 20 to be able to reciprocate. In the valve body 30, the diameter of the base end part 32 is made to be larger than that of the tip part 31 by the taper part 33 formed around the whole outer circumference of the valve body 30. By inserting the tip part 31 into the metering part 23 so as to change a position of the taper part 33 in the reciprocating direction, fluid which passes through a clearance between the metering part 23 and the taper part 33 of the valve body 30 and flows from the inlet port 28 to the outlet port 27 is metered. The metering part 23 is formed with a taper part 24 having the same taper angle as that of the taper part 33 of the valve body 30 at a peripheral edge part of a side to which the tip part 31 of the valve body 30 is inserted. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a flow control valve for an internal combustion engine, such as a PCV valve that controls the flow rate of blow-by gas.

  As a typical example of a flow control valve used in an internal combustion engine, for example, as described in Patent Document 1, a PCV (Positive Crankcase Ventilation) valve used in a blow-by gas reduction device can be cited. Hereinafter, the configuration of such a PCV valve will be described with reference to FIG. FIG. 8 shows a cross-sectional structure of the PCV valve.

  As shown in FIG. 8, this PCV valve includes a case 54 having a circular cross section having an outlet 52 and an inlet 53, and a valve body 55 accommodated in the case 54 so as to be capable of reciprocating. . The case 54 is attached to a cylinder head cover 70 of the internal combustion engine at the base end side portion (the right side portion in FIG. 8). The outlet 54 of the case 54 communicates with the downstream side of the throttle valve (not shown) in the intake passage, while the inlet 53 communicates with the inside of the cylinder head cover 70.

  Further, in the case 54, a measuring section 61 having a circular cross section having a predetermined inner diameter is formed between the inlet 53 and the outlet 52 by the inner wall of the case 54. On the other hand, the valve body 55 has a columnar distal end portion 57, a cylindrical proximal end portion 58 having an outer diameter larger than that of the distal end portion 57, and a diameter increasing from the distal end portion 57 toward the proximal end portion 58. And a tapered portion 59 that connects the distal end portion 57 and the proximal end portion 58. In addition, a valve spring 56 that urges the valve body 55 toward the inlet 53 is provided inside the case 54.

In such a PCV valve, when a negative pressure generated in the intake passage is introduced into the case 54 through the outlet 52, the valve body 55 resists the urging force of the valve spring 56 due to the negative pressure. 52 is displaced toward the side. Then, when the valve body 55 is displaced in this way, the distal end portion 57 is inserted into the measuring portion 61. When the negative pressure in the intake passage further increases, the tapered portion 59 is inserted into the measuring portion 61 in addition to the tip portion 57 of the valve body 55. And the taper part 59 of the valve body 55 is inserted in the measurement part 61 in this way, and when the position of the taper part 59 in the reciprocating direction of the valve body 55 in the measurement part 61 changes, the measurement part 61 and the taper part The amount of blow-by gas flowing from the inlet 53 to the outlet 52 through the gap between the inlet 59 and the outlet 59 is measured (metered).
JP 2005-303922 A

  By the way, in such a PCV valve, when the tip portion 57 is inserted into the measuring portion 61 in a state where the position of the valve body 55 is shifted from the normal position due to the influence of engine vibration or gravity, for example, the taper portion 59 may collide with the peripheral portion 61a of the measuring portion 61, and the contact surface pressure at the contact portion may be excessive, and the peripheral portion 61a of the measuring portion 61 may be deformed. And when such a deformation | transformation arises, there exists a possibility that the flow volume characteristic of a PCV valve may change resulting from it. Such a problem is common not only in the above-described PCV valve but also in the flow rate adjustment valve of another internal combustion engine.

  The present invention has been made in view of the above circumstances, and the purpose thereof is the flow rate of the flow control valve caused by the collision between the tapered portion of the valve body and the peripheral portion of the metering portion and deformation of the peripheral portion. It is to suppress the characteristic change.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, a valve body is accommodated in a case having an inflow port and an outflow port so as to be capable of reciprocating, and a measuring portion having a circular cross section is formed by the inner wall of the case. The diameter of the base end side portion is larger than the tip end side portion by the taper portion formed on the outer periphery over the entire circumference, and the position of the taper portion in the reciprocating direction is inserted by inserting the tip end side portion of the valve body into the measuring portion. In the flow control valve of the internal combustion engine that measures the fluid flowing from the inlet to the outlet through the gap between the metering portion and the tapered portion of the valve body by changing The gist of the invention is that a taper portion that can come into surface contact with the taper portion of the valve body when the valve body is reciprocated is formed on the peripheral edge portion on the side where the tip side portion of the valve body is inserted. is there.

  In the above configuration, even if the valve body of the flow control valve is inserted into the measuring unit in a state of being shifted from the normal position due to engine vibration or the like, the taper unit may collide with the peripheral part of the measuring unit. Since the portion comes into surface contact with the tapered portion formed on the peripheral portion of the measuring portion, it is possible to suppress an excessive contact surface pressure at the contact portion. Therefore, it is possible to suppress deformation at the peripheral portion of the measuring portion, and it is possible to suppress change in the flow rate characteristic of the flow control valve due to such deformation.

  Even in such a state where the valve body is displaced from the normal position, the valve body can be guided into the measuring portion by the surface contact between the tapered portion of the valve body and the tapered portion of the measuring portion. The valve body can be smoothly inserted into the measuring portion.

  In order to bring the tapered portion of the valve body into surface contact with the tapered portion of the peripheral portion of the measuring portion in this way, the tapered portion formed on the peripheral portion of the measuring portion is formed as described in claim 2. It is desirable to have a taper angle equal to the taper portion of the valve body. According to the structure, it can suppress effectively that the contact surface pressure in the contact part becomes excessive. As a result, it is possible to suppress deformation at the peripheral edge of the measuring portion, and it is possible to more effectively suppress changes in the flow rate characteristics of the flow control valve due to such deformation.

  According to a third aspect of the present invention, in the internal combustion engine flow control valve according to the first or second aspect, the case is attached to the internal combustion engine in a state of protruding in a horizontal direction, and the valve body is horizontal. The measuring portion is reciprocated in the direction, and the taper portion of the measuring portion is formed at least in the vertically lower portion in the peripheral portion of the measuring portion.

  In a flow control valve that is attached to an internal combustion engine with the case protruding in the horizontal direction and the valve body reciprocates in the horizontal direction, the valve body may shift downward in the vertical direction due to gravity acting on the valve body. When the valve body is inserted into the measuring part in such a state where the deviation occurs, there is a high possibility that the lower part in the vertical direction of the peripheral part of the measuring part collides with the tapered part of the valve body.

  In this regard, according to the above configuration, since the tapered portion is formed at the peripheral portion of the measuring portion and at least in the vertically lower portion thereof, the peripheral portion of the measuring portion and the tapered portion of the valve body collide with each other. However, the tapered portion comes into surface contact with the tapered portion formed on the peripheral portion of the measuring portion. Therefore, it is possible to suppress deformation at the peripheral edge of the measuring portion, and it is possible to suitably suppress change in the flow rate characteristic of the flow control valve due to such deformation.

  A fourth aspect of the present invention is the flow control valve for an internal combustion engine according to the first to third aspects, wherein the taper portion of the measuring portion is formed over the entire circumference of the peripheral portion of the measuring portion. It is what.

  According to the above configuration, since the tapered portion is formed over the entire circumference of the peripheral portion of the measuring portion, when the valve body is displaced from the normal position due to engine vibration or the like, the displacement direction is any direction. However, since the deformation | transformation in the peripheral part of a measurement part can be suppressed, the change of a flow characteristic can be suppressed more reliably.

  According to a fifth aspect of the present invention, in the flow rate control valve for an internal combustion engine according to any one of the first to fourth aspects, the flow rate control valve is a blow-by gas supplied from the crank chamber of the internal combustion engine to the intake passage. The gist of the invention is that it is a PCV valve for controlling the flow rate.

  Further, as described above, the flow rate control valve according to claims 1 to 4 is embodied as a PCV valve for controlling the flow rate of blow-by gas supplied from the crank chamber of the internal combustion engine to the intake passage, for example. be able to. According to such a configuration, in the PCV valve, it is possible to suppress deformation of the peripheral portion of the measuring portion due to collision between the peripheral portion of the measuring portion and the taper portion of the valve body, and the flow rate characteristics of blow-by gas resulting from the deformation. The change can be suitably suppressed.

  Hereinafter, an embodiment in which a flow control valve of an internal combustion engine according to the present invention is embodied as a PCV valve used in a blow-by gas reduction device will be described with reference to FIGS. FIG. 1 shows a cross-sectional structure of the PCV valve. As shown in FIG. 1, in this PCV valve, a cylindrical case 20 having an outlet 27 and an inlet 28 has a base end side portion (right side portion in FIG. 1) formed by a cylinder head cover 70 of the internal combustion engine. It is supported and attached to the cylinder head cover 70 so as to protrude in the horizontal direction. A valve body 30 is accommodated in the case 20 so as to be capable of reciprocating along the horizontal direction. The outlet 27 of the case 20 communicates with the downstream side of the throttle valve (both not shown) in the intake passage, while the inlet 28 communicates with the inside of the cylinder head cover 70. In addition, in the case 20, a measuring portion 23 having a circular cross section having a predetermined inner diameter is formed by an inner wall of the case 20 between the inlet 28 and the outlet 27. In the case 20, a cushion spring 41 is provided in the vicinity of the outlet 27, while a valve seat 21 is provided in the vicinity of the inlet 28. The valve seat 21 is formed with a communication hole 21 a that communicates the inside of the case 20 and the outside of the case 20 via the inlet 28.

  On the other hand, the valve body 30 has a columnar distal end portion 31, a cylindrical proximal end portion 32 whose outer diameter is set larger than the distal end portion 31, and a diameter increasing from the distal end portion 31 toward the proximal end portion 32. And a tapered portion 33 that connects the distal end portion 31 and the proximal end portion 32. A valve spring 26 that urges the valve body 30 toward the inflow port 28 is provided inside the case 20. Further, a taper portion 24 having a taper angle equal to that of the taper portion 33 of the valve body 30 is formed on the entire circumference of the measuring portion 23 at the peripheral edge portion on the side where the tip end portion 31 of the valve body 30 is inserted.

  In such a PCV valve, since no negative pressure is generated in the intake passage while the engine is stopped, the valve element 30 is urged by the urging force of the valve spring 26 so that the base end portion 32 is in contact with the valve seat 21. (Not shown). On the other hand, since the negative pressure in the intake passage is introduced into the case 20 through the outlet 27 when the engine is started, the valve body 30 has a base end portion 32 in the valve 30 by the action of the negative pressure as shown in FIG. From the state in contact with the seat 21, the valve spring 26 is displaced toward the outlet 27 side against the urging force of the valve spring 26.

  Here, when the engine is under a low load, the opening degree of the throttle valve is reduced and the negative pressure generated in the intake passage is increased. Therefore, as shown in FIG. 3, the valve body 30 is energized by the force based on the negative pressure and flows. Displacement toward the outlet 27 side causes the tip 31 to come into contact with the cushion spring 41. As described above, when the tip 31 of the valve body 30 contacts the cushion spring 41, the tip 31 does not collide with the case 20 even when the valve body 30 is displaced toward the outlet 27. At this time, the flow passage cross-sectional area of the blow-by gas formed between the outer peripheral surface of the valve body 30 and the measuring portion 23 becomes the smallest, and is introduced into the case 20 from the inlet 28 and sucked through the outlet 27. As shown in FIG. 4A, the flow rate of the blow-by gas flowing out into the passage is the minimum flow rate during engine operation.

  On the other hand, the opening of the throttle valve increases during engine load, and the negative pressure generated in the intake passage decreases, so that the valve body 30 is urged by the urging force of the valve spring 26 as shown in FIG. And displaced toward the inlet 28 side. For this reason, the flow passage cross-sectional area of the blow-by gas formed between the outer peripheral surface of the valve body 30 and the metering portion 23 gradually increases with the displacement of the valve body 30 and thus passes through the PCV valve. The flow rate of blow-by gas increases compared to when the engine is under low load. Thus, as the engine load increases, the flow rate of blow-by gas passing through the PCV valve increases as shown in FIG. 4B. When the engine is heavily loaded, the valve body 30 is urged by the urging force of the valve spring 26 and further displaced toward the inlet 28 as shown in FIG. Since the flow passage cross-sectional area of the blow-by gas formed during this period is the largest, the flow rate of the blow-by gas is maximized as shown in FIG.

  In this way, the valve body 30 is inserted into the measuring portion 23, and the position of the tapered portion 33 in the reciprocating direction of the valve body 30 in the measuring portion 23 changes, whereby the measuring portion 23 and the valve body 30 (particularly the tapered portion 33). ), The amount of blow-by gas that flows from the inlet 28 to the outlet 27 through the gap is measured (metered).

According to the embodiment described above, the following effects can be obtained.
(1) As shown in FIG. 5, the valve element 30 is basically maintained at a normal position in the radial direction with respect to the case 20, but forces acting on the valve element 30 such as engine vibration and gravity. As a result, the valve body 30 may be displaced from the normal position as shown in FIG. Here, it is assumed that the normal position is substantially the same as the axis of the case 20 and the axis of the valve body 30.

In the PCV valve of the present embodiment, the taper portion 24 having a taper angle equal to the taper portion 33 of the valve body 30 is formed on the entire periphery of the peripheral portion of the measuring portion 23, so that the valve body 30 is displaced from the normal position. Even if the distal end portion 31 is inserted into the measuring portion 23 in this state, and the taper portion 33 of the valve body 30 collides with the peripheral portion of the measuring portion 23, the valve body as shown in FIG. The 30 taper portions 33 come into surface contact with the taper portion 24 of the measuring portion 23. For this reason, even if contact with the valve body 30 and the measurement part 23 arises, it can suppress that the contact surface pressure in the contact part becomes excessive. As a result, the deformation of the peripheral edge can be suppressed, and the change in the flow rate characteristic of the PCV valve due to such deformation can be suppressed. Further, even when the valve body 30 is shifted from the normal position in this way, the valve body 30 is brought into contact with the taper portion 33 of the valve body 30 and the taper portion of the metering portion 23 to bring the valve body 30 into contact with the metering portion 23. Therefore, the valve body 30 can be smoothly inserted into the measuring portion 23.
(2) In particular, in the PCV valve according to the present embodiment, the tapered portion 24 is formed on the entire circumference of the peripheral portion of the measuring portion 23. Therefore, when the taper portion 24 of the valve body 30 is displaced from the normal position and collides with the peripheral portion of the measuring portion 23, the taper portion 33 is the peripheral portion of the measuring portion 23 regardless of which direction is shifted. Therefore, it is possible to prevent the contact surface pressure at the contact portion from becoming excessive. As a result, since the metering unit 23 is not deformed, it is possible to reliably suppress a change in the flow rate characteristic of the PCV valve.

In addition, embodiment described above can be implemented in the aspect which changed the form suitably as follows.
In the above embodiment, the tapered portion 24 having the same taper angle as the tapered portion 33 of the valve body 30 is formed over the entire circumference of the peripheral portion of the measuring portion 23. Here, the PCV valve exemplified in the above embodiment is attached to the cylinder head cover 70 with the case 20 protruding in the horizontal direction, and the valve body 30 reciprocates in the horizontal direction. It is highly possible that the valve body 30 is shifted downward in the vertical direction due to the acting gravity, and when the valve body 30 is inserted into the measuring unit 23 in such a state that the shift occurs, a vertically lower portion in the peripheral portion of the measuring unit 23 And the taper portion 33 of the valve body 30 are likely to collide with each other. Therefore, as shown in FIG. 7, a configuration is adopted in which the tapered portion 43 is formed only at the lower portion in the vertical direction where the possibility of colliding with the tapered portion 33 of the valve body 30 is high at the peripheral portion of the measuring portion 23. You can also. According to this configuration, since the tapered portion 43 is formed at least at the lower portion in the vertical direction at the peripheral portion of the measuring portion 23, the tapered portion 43 and the valve body 30 at the lower portion in the vertical direction of the peripheral portion of the measuring portion 23. Even if the taper portion 33 collides with the taper portion 33, the taper portion 33 comes into surface contact with the taper portion 43 formed in the lower portion of the peripheral portion of the measuring portion 23 in the vertical direction. Therefore, it is possible to suppress the deformation in the vertically lower portion of the peripheral portion of the measuring portion 23, and it is possible to suitably suppress the change in the flow rate characteristic of the PCV valve due to such deformation.

  In each of the above embodiments, the example in which the case 20 of the PCV valve is mounted horizontally with respect to the internal combustion engine, specifically, the cylinder head cover 70 is shown, but the mounting mode of the case 20 is not limited to this. For example, the case 20 may be attached to an internal combustion engine such as the cylinder head cover 70 in a state of protruding in a vertical direction or a direction inclined with respect to the vertical direction. In this case, if the portion that is likely to collide when the valve body 30 is inserted into the measuring portion 23 can be specified in advance, the tapered portion of the valve body 30 only in the portion that is likely to collide among the peripheral portions of the measuring portion 23. A configuration in which a tapered portion having the same angle as that of 33 is provided can also be adopted.

  In each of the above embodiments, the tapered portions 24 and 43 having the same taper angle as the tapered portion 33 of the valve body 30 are formed on the peripheral portion of the measuring portion 23, but the distal end portion 31 of the valve body 30 is inserted. If the taper portions 24 and 43 of the metering portion 23 and the taper portion 33 of the valve body 30 are in surface contact with each other and excessive deformation at the contact portion is suppressed, the taper portions 24 and 43 of the metering portion 23 are suppressed. And the taper part 33 of the valve body 30 may not necessarily be equal, and they may be different.

  In each of the above-described embodiments, the present invention is embodied in the PCV valve for controlling the blow-by gas flow rate of the internal combustion engine. It can also be applied to a flow rate control valve other than a PCV valve that controls the flow rate of the fluid.

Sectional drawing of the PCV valve | bulb concerning embodiment. Sectional drawing of the PCV valve | bulb concerning embodiment. Sectional drawing of the PCV valve | bulb concerning embodiment. The graph which shows the relationship between an engine load and a blow-by gas flow rate. The expanded sectional view which expands and shows the measurement part vicinity of the PCV valve concerning embodiment. The expanded sectional view which expands and shows the measurement part vicinity of the PCV valve concerning embodiment. The expanded sectional view which expands and shows the measurement part vicinity of the PCV valve concerning the modification of embodiment. Sectional drawing of the conventional PCV valve | bulb.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Case, 21 ... Valve seat, 21a ... Communication hole, 23 ... Metering part, 24 ... Taper part, 26 ... Valve spring, 27 ... Outlet, 28 ... Inlet, 30 ... Valve body, 31 ... Tip part, 32 ... Base end part, 33 ... Tapered part, 41 ... Cushion spring, 43 ... Tapered part, 70 ... Cylinder head cover.

Claims (5)

A valve body is accommodated in a case having an inflow port and an outflow port so as to be able to reciprocate. A measuring portion having a circular cross section is formed by the inner wall of the case, and the valve body is a taper formed on the outer periphery thereof. The proximal end portion of the valve body is enlarged in diameter by the portion, the distal end portion of the valve body is inserted into the measuring portion, and the position of the tapered portion in the reciprocating direction is changed to In a flow control valve for an internal combustion engine that measures fluid flowing from the inlet to the outlet through a gap between the valve body and the tapered portion,
The measuring portion is formed with a tapered portion that can come into surface contact with the tapered portion of the valve body when the valve body is reciprocated at a peripheral portion on a side where the tip side portion of the valve body is inserted. A flow control valve for an internal combustion engine characterized by the above. In the internal combustion engine flow control valve according to claim 1,
A flow control valve for an internal combustion engine, wherein a tapered portion formed at a peripheral portion of the measuring portion has a taper angle equal to a tapered portion of the valve body. The flow control valve for an internal combustion engine according to claim 1 or 2,
The case is attached to the internal combustion engine in a state of protruding in the horizontal direction, and the valve body reciprocates in the horizontal direction,
The flow rate control valve for an internal combustion engine, wherein the taper portion of the measuring portion is formed at least in a vertically lower portion at a peripheral portion of the measuring portion. In the internal combustion engine flow control valve according to any one of claims 1 to 3,
The flow control valve for an internal combustion engine, wherein the taper portion of the measuring portion is formed over the entire circumference of the peripheral portion of the measuring portion. In the internal combustion engine flow control valve according to any one of claims 1 to 4,
The flow rate control valve is a PCV valve for controlling the flow rate of blow-by gas supplied from the crank chamber of the internal combustion engine to the intake passage.

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