JP2005315147A - Pcv valve system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a PCV valve system for preventing generation of an abnormal sound and abnormal abrasion, by restraining an internal valve element from vibrating by self-excitation. <P>SOLUTION: This PCV valve system has a cylindrical valve housing 11 for respectively arranging an inlet port 111 and an outlet port 112 in both end walls, a PCV (positive crankcase ventilation) valve 1 having the tapered valve element 12 arranged in the shaft direction in the valve housing 11 and capable of varying the opening area A of the outlet port 112 and a spring body 13 arranged between the housing 11 and the valve element 12 and energizing and supporting the valve element 12 in the direction for the valve element 12 to increase the opening area A of the outlet port 112, and a downstream side pipe 2 connected to the outlet port 112 of the PCV valve 1. An upstream side orifice 113 or a downstream side orifice is provided in any of the upstream side of the inlet port 111 or the downstream side of the outlet port 112. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a PCV (positive crankcase ventilation) valve system that is interposed between an engine and an intake system and controls the reduction of blow-by gas from the engine to the intake system.

  As an engine blow-by gas reduction device and a PCV valve, for example, there are those shown in FIGS. 11 to 14 (see, for example, Patent Document 1). 50 is an engine, 51 is a cylinder block, 52 is a cylinder head, 53 is a cylinder head cover, 54 is an air cleaner, and 55 is a carburetor. The cylinder head 52 and the carburetor 55 of the engine 50 are connected by an intake pipe 56. In order to reduce blow-by gas generated in the crankcase 57 of the engine 50 to the air cleaner 54, the air cleaner 54 and the cylinder head cover 53 of the engine 50 are connected by a blow-by gas pipe 58. Three branch pipe joints 59 are provided in the middle of the blow-by gas pipe 58, and a connection hose 60 is connected to the branch pipe joint 59, and the connection hose 60 is connected to the intake pipe 56 via the PCV valve 10. The PCV valve 10 has a cylindrical valve housing 11 provided with an inlet port 111 and an outlet port 112 on both ends, respectively, and is disposed in the axial direction in the valve housing 11. The valve body 12 is arranged between the housing 11 and the valve body 12 so that the opening area of the outlet port 112 is increased. And a spring body 13 for supporting the force.

Since the flow rate control of the blow-by gas by the PCV valve is controlled by the balance between the front-rear differential pressure of the valve body 12 and the spring body 13, the controllability of the flow rate is determined by the mass of the valve body 12 and the spring coefficient of the spring body 13. It depends on the balance. Therefore, normally, in order to lift the lightweight valve body 12 only by the differential pressure across the front, the spring body 13 having a somewhat low spring coefficient (for example, 150 N / m) is used, and the fluid flowing in the PCV valve 10 is used. Depending on the magnitude of the force, self-excited vibration is generated between the valve body 12 and the spring body 13. Here, under the condition that the self-excited vibration is not attenuated, the valve body 12 continues to vibrate close to its natural frequency, and the flow rate of blow-by gas cannot be controlled. In addition, the self-excited vibration may cause problems such as abnormal noise or abnormal wear due to the valve body 12 colliding with the wall surface of the housing 11.
Japanese Utility Model Publication No. 3-17215

  As mentioned in the above background art, conventional PCV valves have had problems such as generation of sound and wear due to vibration because the internal valve body vibrates by itself and the predetermined flow rate cannot be controlled.

  The present invention has been created to solve such problems. That is, an object of the present invention is to provide a PCV valve system that suppresses self-excited vibration of an internal valve body and improves flow rate controllability, or prevents generation of abnormal noise and abnormal wear.

  The PCV valve system of the present invention made to solve this problem is a cylindrical valve housing in which an inlet port and an outlet port are respectively provided at both end walls, and is arranged in the axial direction in the valve housing, A tapered valve body having a variable opening area A of the outlet port, and the valve body disposed between the housing and the valve body so that the valve body increases the opening area A of the outlet port. A PCV valve system having a spring body that biases and supports the PCV valve, and a downstream pipe line connected to the outlet port of the PCV valve, wherein the upstream side of the inlet port or the outlet port An upstream throttle or a downstream throttle is provided on either downstream side. Here, the opening area A of the outlet port is an area obtained by subtracting the maximum cross-sectional area of the valve body in which the valve body is inserted and within the opening of the outlet port from the opening area of the outlet port before the valve body is inserted, The value of A varies depending on the insertion position of the valve body.

  Another PCV valve system according to the present invention, which has been made to solve the problem, includes a cylindrical valve housing having an inlet port and an outlet port at both ends, respectively, and an axial direction within the valve housing. A tapered valve body that is arranged to make the opening area A of the outlet port variable, and is arranged between the housing and the valve body so that the valve body increases the opening area A of the outlet port. A PCV valve system having a PCV valve having a spring body that biases and supports the valve body, and a downstream pipe line connected to the outlet port of the PCV valve, and a pipe in the downstream pipe line It is characterized by having a road stop.

The ratio A ₁ / A ₀ between the opening area A ₁ of the downstream aperture and the minimum area A ₀ of the opening area A of the outlet port may be in the range of 4-8.

Alternatively, the ratio A ₂ / A ₀ between the opening area A ₂ of the upstream throttle and the minimum area A ₀ of the opening area A of the outlet port may be in the range of 4-7.

The ratio A ₃ / A ₀ between the opening area A ₃ of the pipe throttle and the minimum area A ₀ of the opening area A of the outlet port may be in the range of 4-8.

Another PCV valve system according to the present invention, which has been made to solve the problem, includes a cylindrical valve housing having an inlet port and an outlet port at both ends, respectively, and an axial arrangement within the valve housing. And a tapered valve body that makes the opening area A of the outlet port variable, and the valve body that is disposed between the housing and the valve body in a direction that increases the opening area A of the outlet port. In a PCV valve system having a PCV valve having a spring body that biases and supports a valve body, and a downstream pipe line connected to the outlet port of the PCV valve, the pressure wave propagation speed in the pipe line is α, where the resonance period of the spring body and the valve body of the PCV valve is T, the pipe length L is (αTd ² /5.94×10 ⁻⁴ ) or less. ing.

It is further preferable that the pipe length L is (αTd ² /1.78×10 ⁻³ ) or less.

1) Operation and effect by providing an upstream throttle or a downstream throttle (Claim 1) When the valve body of the PCV valve vibrates, a volume that fluctuates before and after the valve body due to vibration is required. For example, when the valve body 12 vibrates with the displacement x in FIG. 12, the volume change before and after the valve body 12 becomes σx multiplied by the cross-sectional area σ of the valve body 12. When the front and rear of the valve body 12 are opened as shown in FIG. 12, no resistance force acts on the valve body 12 with respect to this volume change. On the other hand, when the upstream throttle 113 or the downstream throttle 114 is provided before or after the valve body 12 as shown in FIGS. 1 and 4, the fluid is sucked or discharged through the throttles 113 and 114 in order for the volume change to occur. It is necessary to suppress the volume change due to the flow loss at the throttles 113 and 114.

Since the volume change is suppressed by suppressing the vibration of the valve body 12 (resistance to the valve body 12 is large), by providing the upstream throttle 113 or the downstream throttle 114 before or after the valve body 12, the valve body is provided. 12 vibrations can be suppressed.
2) Operation and effect of providing a pipe throttle in the downstream pipe (Claim 2) The downstream pipe 2 (see FIGS. 1 and 4) greatly affects the vibration of the valve body 12 of the PCV valve 1. It is known. This is because the pressure wave generated by the vibration of the valve body 12 is reflected on the connection portion with the intake passage and the surge tank connected to the downstream side pipe line 2 and acts on the valve body 12. Here, the vibration of the valve body 12 can be suppressed by causing the reflected pressure wave (reflected wave) to act in a phase opposite to the vibration phase of the valve body 12. In order to make this reflected wave act effectively, it is necessary to shorten the pipe length to some extent. This is because the action of suppressing the vibration of the valve element (force applied in the direction to cancel the vibration) increases as the length of the pipe is short and the reflected wave is reflected at the pipe end and returned to the PCV valve. . Thus, the vibration of the valve body can be suppressed by shortening the pipe length.

As shown in FIG. 5, by providing a pipe throttle 21 in the pipe 2, the pressure wave is reflected by the pipe throttle 21 and the effect of shortening the pipe length, that is, the vibration of the valve body 12 is suppressed. The action to do can be enlarged.
3) The effect of the ratio A ₁ / A ₀ between the opening area A ₁ of the downstream side throttle and the minimum area A ₀ of the opening area A of the outlet port in the range of 4 to 8 (of claim 3); Effect FIG. 7 shows the result of an experimental investigation of the relationship between the valve body vibration width and A ₁ / A ₀ when the differential pressure across the valve body is about −45 kPa, and from now on, vibration occurs when A ₁ / A ₀ is 8 or less. It can be seen that the width is zero. 7 shows that the mass of the valve body 12 is 5 grams, the spring constant of the spring body 13 is 150 N / m, the length of the downstream pipe 2 is 1.2 m, and the inner diameter of the pipe 2 is 0.008 m. It is a result. However, the lower limit of A ₁ / A ₀ is 4, that is, the maximum value of the variable opening area A of the outlet port is 4A ₀ , and A ₁ needs to be larger than the maximum value of A for the function of the PCV valve. Therefore, by A ₁ / A ₀ is to be in the range of 4 to 8, it is possible to make the oscillation width of the valve element 12 to zero.
4) The effect of the ratio A ₂ / A ₀ between the opening area A ₂ of the upstream throttle and the minimum area A ₀ of the opening area A of the outlet port in the range of 4 to 7 (of claim 4); Effect FIG. 8 shows the result of an experimental investigation of the relationship between the valve body vibration width and the A ₂ / A ₀ when the differential pressure across the valve body is about −45 kPa. From now on, vibration occurs when A ₂ / A ₀ is 7 or less. It can be seen that the width is zero. That is, by making A ₂ / A ₀ in the range of 4 to 7, the vibration width of the valve body can be made zero.
5) Actions and effects of the ratio A ₃ / A ₀ of the opening area A ₃ of the pipe throttle and the minimum area A ₀ of the opening area A of the outlet port in the range of 4 to 8 (Claim 5) By setting the ratio A ₃ / A ₀ between the opening area A ₃ of the path restriction and the minimum area A ₀ of the opening area A of the outlet port to a range of 4 to 8, reflection of pressure waves in the pipe line at the restriction part. Occurs, and the vibration of the valve body is suppressed. Further, the vibration of the valve and the like is suppressed by increasing the flow resistance and the like due to the restriction.

FIG. 9 shows the results of an experimental investigation of the relationship between the valve body vibration width and A ₃ / A ₀ when the differential pressure across the valve body is −45 kPa. The pipe throttle is inserted 200 mm downstream from the outlet port of the PCV valve, and other conditions are the same as in FIG. Although now A ₃ / A ₀ <understood that vibration of the valve body 8 can be suppressed, since the A ₃ / A ₀ <not fulfill the function of the PCV valve in 4 as described above, the A ₃ / A ₀ 4 By setting it as the range of ˜8, the valve body vibration width can be made zero while maintaining the function of the PCV valve.
6) Actions and effects by making the pipe length L less than αTd ² /(5.94×10 ⁻⁴ ) (Claim 6) The attenuation rate downstream of the pressure wave generated by the vibration of the valve body is If η,
η = CL / αTd ² (1)
Here, C is a proportionality constant, and the smaller the damping rate η, the more the vibration of the valve body is suppressed by the reflected wave.

When the mass of the valve body is m, the spring constant of the spring body is k, the thickness of the pipe is e, the Young's modulus of the pipe material is E, the bulk modulus of fluid is K, and the density of the fluid is ρ,
T = 2π (m / k) ^1/2 (2)
α = (K / ρ) ^1/2 / (1+ (K / E) (d / e)) ^1/2 (3)
It is. FIG. 10 is a result of experimentally determining the relationship between the attenuation factor η and the pipe length L when m = 5 grams, k = 150 N / m, α = 273 m / s, and d = 0.006 m. . From this, C is determined so that the attenuation rate η is 0 or more.
Since η = CL / αTd ² ≦ 1 and L ≦ αTd ² /C=0.6, C = 5.94 × 10 ⁻⁴ . That is, by setting the pipe length L to αTd ² /(5.94×10 ⁻⁴ ) or less, the damping factor η can be set to 0 or more (the vibration of the valve body can be suppressed).
7) Actions and effects obtained by reducing the pipe length L to αTd ² /(1.78×10 ⁻³ ) or less (Claim 7) C is obtained from FIG. Then, C = 1.78 × 10 ⁻³ . That is, by setting the pipe length L to αTd ² /(1.78×10 ⁻³ ) or less, the damping rate η can be set to 0.8 or more (the vibration of the valve body can be further suppressed). .

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same component and description is abbreviate | omitted.

FIG. 1 is a cross-sectional view of a PCV valve system showing an embodiment of the present invention. 2 is a cross-sectional view taken along the line aa in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line bb in FIG. This PCV valve system has a PCV valve 1 and a downstream pipe line 2. The PCV valve 1 has a cylindrical valve housing 11 having an inlet port 111 at the upper end, an outlet port 112 at the lower end, and an upstream throttle 113 having an opening area A ₂ at the upstream portion (upper end portion) of the inlet port 111; A tapered valve body 12 that is disposed in the valve housing 11 in the axial direction and has a variable opening area A (see FIG. 2) of the outlet port 112, and is disposed between the housing 11 and the valve body 12. Has a spring body 13 that biases and supports the valve body 12 in the direction of increasing the opening area A of the outlet port 112. The ratio of the opening area A ₂ of the upstream throttle 113 to the minimum area A ₀ of the opening area A of the outlet port 112 is 4-7.

Next, the operation of the PCV valve system configured as described above will be described. In the present invention, as shown in FIG. 1, the upstream throttle 113 having an opening area A ₂ is provided at the upstream portion of the inlet port 111 so that the ratio of A ₂ to A is 4 to 7. The volume change in front of the valve body 12 due to this vibration is suppressed, and the vibration of the valve body 12 becomes zero.

FIG. 4 is a cross-sectional view of a PCV valve system showing a second embodiment of the present invention. In the PCV valve system of the present invention, a downstream throttle 114 having an opening area A ₁ is provided in the downstream portion of the outlet port 112 instead of the upstream throttle 113 of the first embodiment, and the ratio of A ₁ and A ₀ is 4 to 4. Except for setting to 8, it is the same as the PCV valve system of the first embodiment.

FIG. 5 is a cross-sectional view of a PCV valve system showing a third embodiment of the present invention. In the PCV valve system of the present invention, a pipe throttle 21 having an opening area A ₃ is provided in the upstream portion of the downstream pipe 2 in place of the upstream throttle 113 of the first embodiment. ₃ is the same as the PCV valve system of the first embodiment except that the ratio A ₃ / A ₀ of the opening area A of the outlet port 112 to the minimum area A ₀ is in the range of 4-8.

  The reflection of the pressure wave generated by the vibration of the valve body 12 occurs in the pipeline restrictor 21, and the vibration of the valve body 12 is suppressed. Note that the pipe throttle 21 is preferably provided as close to the outlet port 112 of the PCV valve 1 as possible. The closer the position of the pipe restrictor 21 is to the outlet port, the greater the vibration suppression effect.

FIG. 6 is a cross-sectional view of a PCV valve system showing a fourth embodiment of the present invention. The PCV valve system of the present invention eliminates the upstream throttle 113 of the first embodiment, and the length L of the pipe line 2 is equal to αTd ² /(5.94×10 ⁻⁴ ). Mass m = 5 grams, spring constant k of spring body 13 = 150 N / m, thickness e = 1.5 mm of pipe 12, inner diameter d = 0.006 m of pipe 12, Young's modulus E = 1 of pipe 12 ^{.0 × 10 6 N / m 2} , bulk modulus of the fluid K = 140000N / m ^2, the density of the fluid ρ = 1.205kg / m ^3, duct pressure wave propagation velocity α = 273m / s, as, L = 0.6 m The same as the PCV valve system of the first embodiment except that it is 0.6 m.

  In the present invention, by setting L = 0.6 m, the pressure attenuation rate becomes 0 or more, and the self-excited vibration of the valve body 12 is suppressed. If it is shorter than 0.6 m, the pressure decay rate increases and self-excited vibration is further suppressed. Even if the length L of the pipe 12 is 0.6 m, the pressure wave represented by the formula (3) is obtained by increasing the thickness e of the pipe 12 and configuring the pipe 12 with a material having a large Young's modulus E. The same action as when the propagation velocity α is increased to make the effective pipe length less than 0.6 m can be obtained.

Furthermore, the length L of the pipe line 2 is preferably αTd ² /(1.78×10 ⁻³ ) or less, that is, 0.2 m or less. The pressure decay rate becomes 0.8 or more, and the self-excited vibration is further suppressed.

It is sectional drawing of the PCV valve system in the 1st Embodiment of this invention. It is aa sectional drawing in FIG. It is bb sectional drawing in FIG. It is sectional drawing of the PCV valve system in the 2nd Embodiment of this invention. It is sectional drawing of the PCV valve system in the 3rd Embodiment of this invention. It is sectional drawing of the PCV valve system in the 4th Embodiment of this invention. It is a graph showing the relationship between the valve body vibration width of the PCV valve system and A ₁ / A ₀ in the second embodiment of the present invention. It is a graph showing the relationship between the valve body vibration width of the PCV valve system and A ₂ / A ₀ in the first embodiment of the present invention. It is a third graph showing the relationship between the valve body vibration width of the PCV valve system and A ₃ / A ₀ in the embodiment of the present invention. It is a graph which shows the relationship between the pressure attenuation factor of the PCV valve system in 4th Embodiment of this invention, and the pipe line length L. FIG. It is a schematic explanatory drawing of the conventional blowby gas reduction apparatus. It is sectional drawing of the conventional PCV valve | bulb. It is aa sectional drawing of FIG. It is bb sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PCV valve 2 Downstream side pipe line 11 Valve housing 12 Valve body 13 Spring body 21 Pipe line throttle 111 Inlet port 112 Outlet port 113 Upstream side throttle 114 Downstream side throttle

Claims (7)

A cylindrical valve housing in which an inlet port and an outlet port are provided at both ends, respectively, and a tapered valve body which is arranged in the axial direction in the valve housing and has a variable opening area A of the outlet port; And a spring body disposed between the housing and the valve body and biasingly supporting the valve body in a direction in which the valve body increases the opening area A of the outlet port. A ventilation) PCV valve system having a valve and a downstream line connected to the outlet port of the PCV valve;
A PCV valve system comprising an upstream throttle or a downstream throttle on either the upstream side of the inlet port or the downstream side of the outlet port. A cylindrical valve housing in which an inlet port and an outlet port are provided at both ends, respectively, and a tapered valve body which is arranged in the axial direction in the valve housing and has a variable opening area A of the outlet port; A PCV valve having a spring body disposed between the housing and the valve body and biasingly supporting the valve body in a direction in which the valve body increases the opening area A of the outlet port, and the PCV A PCV valve system having a downstream line connected to the outlet port of the valve;
A PCV valve system comprising a pipe throttle in the downstream pipe. 2. The PCV valve system according to claim 1, wherein a ratio A ₁ / A ₀ between an opening area A ₁ of the downstream throttle and a minimum area A ₀ of the opening area A of the outlet port is in the range of 4-8. _2. The PCV valve system according to claim 1, wherein a ratio A ₂ / A ₀ between an opening area A ₂ of the upstream throttle and a minimum area A ₀ of the opening area A of the outlet port is in the range of 4-7. _3. The PCV valve system according to claim 2, wherein a ratio A ₃ / A ₀ between an opening area A ₃ of the pipe restriction and a minimum area A ₀ of the opening area A of the outlet port is in the range of 4-8. A cylindrical valve housing in which an inlet port and an outlet port are provided at both ends, respectively, and a tapered valve body which is arranged in the axial direction in the valve housing and has a variable opening area A of the outlet port; A PCV valve having a spring body disposed between the housing and the valve body and biasingly supporting the valve body in a direction in which the valve body increases the opening area A of the outlet port, and the PCV A PCV valve system having a downstream line connected to the outlet port of the valve;
When the inner diameter of the pipe is d, the pressure wave propagation velocity in the pipe is α, and the resonance period of the spring body and the valve body of the PCV valve is T, the pipe length L is αTd ² / (5.94 × 10 ⁻⁴ ) or less PCV valve system, The PCV valve system according to claim 6, wherein the pipe length L is set to αTd ² /(1.78×10 ⁻³ ) or less.

Images