JP2005273599A - Blow-by gas reducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blow-by gas reducing device capable of suppressing inflow of oil into an intake passage, even when pressure in the intake passage is lowered according to an operation state of an engine. <P>SOLUTION: The blow-by gas reducing device comprises a casing 15; an oil separator 16 making blow-by gas flowing in from an inflow port 11 upwardly pass, and separating/removing oil mixed into the blow-by gas; a PCV valve 17 provided above the oil separator 16 and downstream to the oil separator 16, and intercepting a communicating passage 18 communicating the inflow port 11 and an outflow port 17 only when pressure in the outflow port 14 side communicating to the intake passage of the engine is lower than pressure immediately downstream to the oil separator 16 by not less than a predetermined value; and a bypass passage 23 having a flow passage cross sectional area smaller than the maximum opening area of the PCV valve 17, and bypassing the PCV valve 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a blow-by gas reduction device that introduces and processes blow-by gas into an intake passage, and more particularly to a technique for suppressing the inflow of oil into the intake passage.

As described in Japanese Patent Laid-Open No. 2002-295224 (Patent Document 1), the blow-by gas reduction device introduces blow-by gas that has leaked from the combustion chamber of the engine into the crankcase into the intake passage of the engine through piping. To process. At this time, an oil separator is interposed in the pipe, and the oil mixed in the blow-by gas is separated and removed to prevent the oil from flowing into the intake passage.
JP 2002-295224 A

However, in such a blow-by gas reduction device, when the pressure in the intake passage decreases as the engine operating state changes, the differential pressure between the crankcase and the intake passage increases. There is a risk of flowing into the passage.
Therefore, in view of the conventional problems as described above, the present invention allows blow-by gas to pass from the lower side to the upper side of the oil separator, and when the pressure in the intake passage decreases according to the change in the operating state of the engine, An object of the present invention is to provide a blow-by gas reduction device that suppresses the inflow of oil into the intake passage by providing a valve that shuts off the communication passage to the intake passage of gas.

  For this reason, the invention described in claim 1 has an inflow port through which blow-by gas of the engine flows in and an outflow port in communication with the intake passage of the engine, and a communication path in which the inflow port and the outflow port communicate with each other. A casing that has a built-in casing, an oil separator that separates and removes oil mixed in the blow-by gas while allowing the blow-by gas flowing in from the inlet to pass upward from below, and the oil separator in the casing A valve that is provided upstream of the oil separator and upstream of the outlet, and shuts off the communication passage only when the pressure on the outlet side is lower than the pressure immediately downstream of the oil separator by a predetermined value or more. And the flow passage cross-sectional area is smaller than the maximum opening area of the valve, and the upstream side and the downstream side of the valve are bypassed. Wherein the blow-by gas returning device is configured to include a bypass passage, a to.

According to a second aspect of the present invention, the oil separator is substantially coaxial with the inflow port and is provided above the inflow port, and the casing has the oil separated and removed by the oil separator from the inflow port. It is provided at a position where it flows down into the engine.
The invention according to claim 3 is characterized in that the casing is directly attached to the engine so that an opening of the engine that discharges the blow-by gas and the inflow port coincide with each other.

The invention according to claim 4 is characterized in that the oil separator is formed of a porous material.
The invention according to claim 5 is characterized in that the oil separator is detachably inserted into a recess that forms the inflow port provided in the casing.

  According to the first aspect of the present invention, part of the engine blow-by gas flows into the inlet, passes through the oil separator, and is introduced into the intake passage from the outlet. At this time, the oil mixed in the blow-by gas is separated and removed by the oil separator. Here, when the pressure on the outlet side is lower than the pressure immediately downstream of the oil separator by a predetermined value or more, the communication path is blocked by the valve, so that the blow-by gas is introduced into the intake path through the bypass path. . At this time, since the cross-sectional area of the bypass passage is smaller than the maximum opening area of the valve, the pressure immediately downstream of the oil separator increases due to the back pressure. Therefore, the difference between the pressure on the upstream side and the pressure on the downstream side of the oil separator is reduced, so that the flow rate of blow-by gas is reduced. Further, the blow-by gas passes from the lower side to the upper side of the oil separator, and the valve provided downstream of the oil separator is arranged above the oil separator, so that it is difficult for oil to flow into the valve.

  As a result, even when the pressure in the intake passage of the engine is reduced in accordance with the change in the operating state of the engine, the oil is prevented from flowing into the intake passage, so that the fuel caused by the oil flowing into the intake passage The abnormal combustion and the abnormal consumption of oil can be prevented, and the blow-by gas can be introduced into the intake passage, so that the performance of the blow-by gas reduction device can be ensured.

  According to the second aspect of the present invention, the oil separator is provided substantially coaxially with and above the inflow port, and the casing has the oil separated and removed by the oil separator flowing from the inflow port into the engine. Since it is provided at the position, the oil separated and removed by the oil separator flows from the oil separator through the inlet and flows down into the engine. Thereby, consumption of oil can be suppressed.

According to the third aspect of the present invention, the casing is directly attached to the engine so that the opening of the engine that discharges blow-by gas and the inflow port coincide with each other, and therefore, the piping that connects the opening and the inflow port. Is not required, an increase in the number of parts is suppressed, and an increase in cost can be suppressed.
According to the invention described in claim 4, since the oil separator is formed of a porous material, the oil separator can have a simple structure.

  According to the invention described in claim 5, since the oil separator is detachably inserted into the concave portion forming the inlet provided in the casing, the oil separator can be easily cleaned and replaced.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, an opening 3 through which blow-by gas in the crankcase 2 can be discharged is provided at the top of the engine 1. A blow-by gas reduction device 10 is provided above the opening 3 and is directly attached to the engine 1 with a bolt (not shown). An inlet 11 is provided in the lower part of the blow-by gas reduction device 10, and the opening 3 and the inlet are arranged so that blow-by gas flows into the inlet 11 and oil flows down from the inlet 11 into the engine 1. 11 is matched. Further, the blow-by gas reduction device 10 is provided with an outlet 14 that communicates with an intake passage 13 of the engine 1 via a pipe-like blow-by gas passage 12.

As shown in FIG. 2, the blow-by gas reduction device 10 includes an oil separator 16 and a PCV (Positive Crankcase Ventilation) valve 17 in a casing 15. The oil separator 16 and the PCV valve 17 are interposed in a communication path 18 that connects the inlet 11 and the outlet 14 provided in the casing 15.
The oil separator 16 is formed of a porous material such as sponge, for example, and the blow-by gas can pass through the inside of the oil separator 16 and separates and removes the oil mixed in the blow-by gas. The oil separator 16 is substantially coaxial with the inlet 11 and is provided above the inlet 11. The oil separator 16 passes through the inlet 11 provided in the casing 15 so that blow-by gas flowing from the inlet 11 passes upward from below. It inserts in the recessed part 19 to form so that attachment or detachment is possible.

  The PCV valve 17 is provided above the oil separator 16, downstream of the oil separator 16 and upstream of the outflow port 14. The PCV valve 17 has a valve body 21 that is in close contact with the substantially conical sheet surface 20 provided on the inner wall of the communication path 18 between the oil separator 16 and the outlet 14. The valve body 21 is movable in the axial direction of the seat surface 20 and is urged toward the seat surface 20 by the bellows 22. The elasticity of the bellows 22 is such that the valve body 21 and the seat surface 20 are in close contact with each other to block the communication passage 18 only when the pressure on the outlet 14 side is lower than the pressure immediately downstream of the oil separator 16 by a predetermined value or more. Force is set. Further, a bypass path 23 is provided in which the flow path cross-sectional area is smaller than the maximum opening area of the PCV valve 17 and the PCV valve 17 is bypassed by communicating the upstream side and the downstream side of the seat surface 20.

  With such a configuration, part of the blow-by gas of the engine 1 flows into the inlet 11 from the opening 3, passes through the oil separator 16, and passes through the oil outlet 16 through the blow-by gas passage 12 in the intake passage 13. To be introduced. At this time, the oil mixed in the blow-by gas is separated and removed by the oil separator 16. Here, in the normal state, the blow-by gas passes through the opening of the PCV valve 17 or the bypass passage 23 and is introduced into the intake passage 13 from the outlet 14 via the blow-by gas passage 12. On the other hand, when the pressure on the outlet 14 side becomes lower than the pressure immediately downstream of the oil separator 16 by a predetermined value or more, the communication path 18 is blocked by the PCV valve 17, so that the blow-by gas passes through the bypass path 23, It is introduced into the intake passage 13 from the outlet 14 through the blow-by gas passage 12. At this time, since the cross-sectional area of the bypass passage 23 is smaller than the maximum opening area of the PCV valve 17, the pressure immediately downstream of the oil separator 16 is increased by the back pressure. Accordingly, the difference between the pressure on the upstream side and the pressure on the downstream side of the oil separator 16 is reduced, so that the flow rate of blow-by gas is reduced. Further, the blow-by gas passes from the lower side to the upper side of the oil separator 16 and the PCV valve 17 provided downstream of the oil separator 16 is disposed above the oil separator 16, so that it is difficult for oil to flow into the PCV valve 17.

  As a result, even when the pressure in the intake passage 13 decreases in accordance with a change in the operating state of the engine 1, the oil is prevented from flowing into the intake passage 13, so that the oil flows into the intake passage 13. As a result, abnormal combustion of fuel and abnormal consumption of oil can be prevented, and blow-by gas can be introduced into the intake passage 13, so that the performance of the blow-by gas reduction device can be ensured.

  Further, the oil separator 16 is provided substantially coaxially with and above the inlet 11, and the casing 15 is provided at a position where the oil separated and removed by the oil separator 16 flows from the inlet 11 into the engine 1. Therefore, the oil separated and removed by the oil separator 16 flows from the oil separator 16 through the inlet 11 into the engine 1. Thereby, consumption of oil can be suppressed.

Since the oil separator 16 is formed of a porous material such as a sponge, for example, the oil separator 16 can have a simple structure. Furthermore, since the oil separator 16 is detachably inserted into the recess 19 that forms the inlet 11 provided in the casing 15, the oil separator 16 can be easily cleaned and replaced.
In addition, since the oil separator 16 and the PCV valve 17 are built in the casing 15 and the bypass path 23 is provided in the casing 15, a compact configuration can be achieved. Furthermore, since the casing 15 is directly attached to the engine 1 so that the opening 3 and the inlet 11 coincide with each other, piping for connecting the inlet 11 and the opening 3 is unnecessary, and the number of parts increases. Is suppressed, and an increase in cost can be suppressed.

Reference diagram showing a configuration of an engine employing a blow-by gas reduction device in an embodiment of the present invention Reference diagram showing the structure of the blow-by gas reduction device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 3 Opening part 11 Inlet 13 Inlet passage 14 Outlet 15 Casing 16 Oil separator 17 PCV valve 19 Concave part 23 Bypass path

Claims (5)

A casing having an inflow port through which blow-by gas of the engine flows in and an outflow port communicating with the intake passage of the engine, and a communication path communicating the inflow port and the outflow port inside;
An oil separator that is incorporated in the casing and separates and removes oil mixed in the blow-by gas while allowing the blow-by gas flowing in from the inlet to pass upward from below;
Provided above the oil separator in the casing, downstream of the oil separator and upstream of the outlet, and only when the pressure on the outlet side is lower than the pressure immediately downstream of the oil separator by a predetermined value or more. A valve for blocking the communication path;
A bypass passage having a flow path cross-sectional area smaller than the maximum opening area of the valve and bypassing the upstream side and the downstream side of the valve;
A blow-by gas reduction device comprising:   The oil separator is substantially coaxial with the inlet and provided above the inlet, and the casing is provided at a position where oil separated and removed by the oil separator flows down from the inlet into the engine. The blow-by gas reduction device according to claim 1.   3. The blow-by gas reduction device according to claim 1, wherein the casing is directly attached to the engine such that an opening of the engine that discharges the blow-by gas and the inflow port coincide with each other. 4.   The blow-by gas reduction device according to any one of claims 1 to 3, wherein the oil separator is formed of a porous substance.   The blow-by gas reduction device according to any one of claims 1 to 4, wherein the oil separator is detachably inserted into a concave portion that forms the inflow port provided in the casing.

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