JPH0663809U - Blow-by gas reduction device - Google Patents

Abstract

(57) [Summary] [Objective] By suppressing the intake pulsation in the intake passage, high-frequency vibration of the PCV valve is suppressed, thereby preventing an abnormal increase in crankcase internal pressure and increasing the durability of the PCV valve PROBLEM TO BE SOLVED: To provide a blow-by gas reducing device capable of improving the above. [Structure] In a blow-by gas reducing apparatus provided with a communication passage that connects a space where blow-by gas is accumulated in an internal combustion engine and an intake passage 1 and a valve mechanism 8 that opens and closes the communication passage, 1. A blow-by gas reducing device, characterized in that pulse pressure damping means 9, 10, 12 for damping pressure fluctuations due to intake pulsation are provided between the blow-by gas reducing means 1 and 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blowby gas returning device for sending blowby gas from the inside of a crankcase or a cylinder head cover to an intake passage.

[0002]

[Prior art]

 During engine operation, some exhaust gas and unburned gas leak from the combustion chamber into the crankcase. Therefore, the engine oil becomes thinner or deteriorates due to the influence of heat, moisture in the combustion gas, or fuel components to generate sludge. In order to prevent this, a ventilator called a breather was conventionally installed in the crankcase to release it into the atmosphere, but this blow-by gas contains a large amount of hydrocarbons and becomes a source of air pollution. Therefore, there is provided a blow-by gas reduction device (PCV device) which is forcibly introduced into the intake system and again fed into the combustion chamber for combustion.

There are three types of this PCV device, a shield system, an open system, and a closed system, but the closed system is generally adopted in many cases. In the closed system, the inside of the crankcase communicates with the intake passage on the one hand, and the inside of the cylinder head cover communicates with the intake passage on the other, so that blow-by gas is sucked from one of the passages in response to a change in load. At the same time, the atmosphere is introduced from the other communication passage to limit the pressure fluctuation in the crankcase and prevent blow-by gas from being released into the atmosphere. A ventilation valve (PCV valve) is provided in the middle of the communication passage communicating with the intake passage in order to adjust the flow rate of the blow-by gas according to the load.

[0004]

[Problems to be solved by the device]

 As this PCV valve, the one shown in FIG. 6 is generally used. That is, a ventilation hole 2 is formed in the intake manifold 1, and a cover 4 having a breathing hole 3 is attached to the outside of the intake manifold 1 so as to cover the ventilation hole 2 and a valve body is provided inside the cover 4. A diaphragm 5 that is formed and can close the ventilation hole 2, a spring seat 6 that abuts on the diaphragm 5, and a spring 7 that is interposed between the spring sheet 6 and the cover 4 are provided. It constitutes the PCV valve 8.

By the way, in the intake passage such as the intake manifold 1 in which the intake air is flowing, pressure fluctuations due to intake pulsation of a few millisecond cycle occur, and therefore the pulsating pressure acts on the diaphragm 5. As a result, high-frequency vibration occurs, and as a result, the pressure regulating function is lost and the internal pressure of the crankcase rises abnormally. Further, there is a problem that the diaphragm 5, which is generally made of rubber, is fatigued and deteriorates in a short period of time due to the vibration of the high frequency.

In view of the above problems, the present invention suppresses the high frequency vibration of the PCV valve by damping the intake pulsation in the intake passage, thereby preventing the abnormal increase in the crankcase internal pressure. It is an object of the present invention to provide a blow-by gas reduction device that can improve the durability of a PCV valve.

[0007]

[Means for Solving the Problems]

 The blow-by gas returning apparatus of the present invention for achieving the above object is a blow-by gas provided with a communication passage for communicating a space where blow-by gas of an internal combustion engine is stored with an intake passage, and a valve mechanism for opening and closing the communication passage. In the reducing device, a pulse pressure attenuating means for attenuating pressure fluctuation due to intake pulsation is provided between the valve mechanism and the intake passage.

The space where the blow-by gas is stored is a space formed inside the crankcase, the cylinder head cover, etc., and the intake passage is the intake manifold, the intake pipe, or the air cleaner case. This is the flow path for inhaled air. Further, the pulse pressure damping means is not particularly limited as long as it can attenuate the pressure fluctuation due to the suction pulsation exerted on the valve mechanism by expansion, resistance or the like.

[0009]

[Work]

 Since the blow-by gas returning device of the present invention has the above-mentioned configuration, the pulse pressure reducing means attenuates the pressure fluctuation due to the intake pulsation generated in the intake passage and suppresses the high frequency vibration of the valve mechanism. .

[0010]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. The same members as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. In the blow-by gas reducing apparatus according to the first embodiment of the present invention shown in FIG. 1, a plate 10 having a vent hole 9 is attached by a bolt 11 in an intake manifold 1 having a PCV valve 8 attached, and the plate 10 and the PCV are attached. A chamber 12 is defined between the valve 8 and the valve 8.

When the blow-by gas is not very much accumulated in the space inside the crankcase or the space inside the cylinder head cover, the internal pressure of these spaces is relatively low, and the spring 7 applies the valve in the valve closing direction. The diaphragm 5 of the PCV valve 8 which is energized keeps the ventilation hole 2 of the intake manifold 1 closed. When the blow-by gas accumulated in the space reaches a predetermined pressure, the diaphragm 5 separates from the valve seat 13 against the elastic force of the spring 7, and the blow-by gas is blown into the intake manifold 1 through the vent hole 2, the chamber 12, and the chamber 12. It is fed into the intake manifold 1 through the ventilation holes 9 formed in the plate 10.

By the way, in the intake manifold 1 through which intake air flows, a pressure change due to intake pulsation occurs, but when a high-pressure component of the pulsation pressure flows from the intake manifold 1 into the chamber 12, an expansion action occurs. Since the pressure is reduced by the chamber 12, the pressure fluctuation due to the intake pulsation is attenuated by the chamber 12, and it is possible to suppress the high-frequency vibration of the diaphragm 5.

Therefore, the PCV valve 8 can normally maintain the pressure regulating function, prevent the crankcase internal pressure from rising abnormally, and reduce the fatigue of the diaphragm 5 due to the high frequency vibration to improve its durability. Can be improved. In the blow-by gas returning apparatus according to the second embodiment of the present invention shown in FIG. 2, the position of the vent hole 9 formed in the plate 10 is shifted from the position of the vent hole 2 formed in the intake manifold 1.

In the case of the second embodiment, as compared with the first embodiment, the flow path between the ventilation hole 9 formed in the plate 10 and the ventilation hole 2 formed in the intake manifold 1 is bent. Therefore, the resistance to intake pulsation increases, and the high frequency vibration of the diaphragm 5 of the PCV valve 8 is further reduced. A blow-by gas returning apparatus according to a third embodiment of the present invention shown in FIG. 3 has a large number of small-diameter vent holes 9 formed in a plate 10. In the case of the third embodiment, the total area of the inner peripheral wall 14 of the ventilation hole 9 can be increased with respect to the total flow path cross-sectional area of the ventilation hole 9 to increase the resistance to intake pulsation. Similar to the example 2, the effect of further reducing the high frequency vibration of the diaphragm 5 can be obtained.

The blow-by gas returning apparatus according to the fourth embodiment of the present invention shown in FIG. 4 is the plate 10 shown in the first embodiment having a hole 15 for removing oil. This is to prevent the oil mist mixed in the blow-by gas from flowing into the chamber 12 from the crankcase or cylinder head cover side and collecting in the chamber 12.

In each of the above-described embodiments, the separate plate 10 is fixed in the intake manifold 1 by the bolts 11 to define the chamber 12, but when the intake manifold 1 is cast, the chamber 12 is formed. May be integrally formed. In each of the above-mentioned embodiments, the chamber 12 is formed to obtain the pulse pressure damping effect based on the expansion action. Next, the blow-by gas reducing apparatus in Embodiment 5 of the present invention shown in FIG. Intake pulsation is attenuated.

In the fifth embodiment, the ventilation hole 2 of the intake manifold 1 covered by the cover 4 of the PCV valve 8 has a small diameter and a large number of openings are formed. The total sum of the flow passage cross-sectional areas of the large number of vent holes 2 is set to be equal to or larger than that of the single hole shown in each of the above-mentioned embodiments. As a result, the resistance to the intake pulsation can be increased as in the case of the third embodiment while maintaining a good flow of the blow-by gas, so that the high frequency vibration of the diaphragm 5 can be sufficiently reduced. Therefore, the pressure regulating function of the PCV valve 8 can be normally maintained, an abnormal increase in the crankcase internal pressure can be prevented, and the durability of the diaphragm 5 can be improved.

[0018]

[Effect of device]

 The blow-by gas returning device of the present invention is a blow-by gas returning device provided with a communication passage for communicating a space where blow-by gas is accumulated in an internal combustion engine and an intake passage, and a valve mechanism for opening and closing the communication passage. Since the pulse pressure damping means for damping the pressure fluctuation due to the intake pulsation is provided between the intake passage and the intake passage, the following effects can be obtained.

The pulse pressure attenuating means can reduce the pressure fluctuation due to the intake pulsation generated in the intake passage, and can suppress the high frequency vibration of the valve mechanism. Therefore, it is possible to prevent an abnormal increase in the internal pressure in the space where blow-by gas is accumulated, such as the crankcase and the cylinder head cover, and it is possible to improve the durability of the valve mechanism.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a blow-by gas returning apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a blow-by gas returning apparatus according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a blow-by gas returning apparatus according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a blow-by gas returning apparatus according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a main part of a blow-by gas returning apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a main part of a conventional blow-by gas returning apparatus.

[Explanation of symbols]

1 intake passage (intake manifold) 8 valve mechanism (P
CV valve) 9 Pulse pressure damping means (vent) 10 Pulse pressure damping means (plate) 12 Pulse pressure damping means (chamber)

Claims (1)

[Scope of utility model registration request] 1. A blow-by gas returning apparatus provided with a communication passage that communicates a space where blow-by gas of an internal combustion engine is stored with an intake passage, and a valve mechanism that opens and closes the communication passage.
A blow-by gas reducing device, characterized in that pulse pressure damping means for damping pressure fluctuation due to intake pulsation is provided between the valve mechanism and the intake passage.