JP2017066963A - Filter for blow-by gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter for blow-by gas further improved by devising a structure to prevent problems caused by an increase in an inflow-side pressure, such as incapability of returning a liquid component like oil and the degradation of a filtering function.SOLUTION: In a filter for blow-by gas 15 having a filter case 15B and a filter material 15A, a return port 15c to which a return passage 17 communicating to the inside of a crank case 4 can be connected is disposed on a filter rear region r at a downstream side in a blow-by gas flowing direction with respect to the filer material 15A in the filter case 15B. There is also provided a check valve 21 having checking effect from the return port 15c toward the filter rear region r. A short-circuit passage 23 is formed to communicate between a filter front region f at an upstream side in the blow-by gas flowing direction with respect to the filter material 15A in the filter case 15B and an upstream side of the check valve 21 in a checking effect direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blow-by gas filter in a diesel engine or the like, and more specifically, a blow-by gas reduction passage having a filter case and a filter medium accommodated therein to return blow-by gas in a crankcase to an intake passage. It is related with the filter for blow-by gas provided in.

  Blow-by gas refers to a mixture or combustion gas in a combustion chamber of an internal combustion engine that has leaked into the crankcase from the gap between the piston and the cylinder (specifically, the gap between the piston ring and the cylinder). That is, unburned gas and exhaust gas, and what is called oil mist in which these are mixed with oil are also included. When this blow-by gas enters the crankcase, it causes engine oil deterioration, metal corrosion, and air pollution.

  Therefore, a mechanism is generally adopted in which the blow-by gas accumulated in the crankcase is recirculated to the intake path, mixed with a new air-fuel mixture, burned, and not released into the atmosphere as it is. It is a reduction device. The blow-by gas reduction device is provided with a filter for capturing liquid components such as oil and moisture in the blow-by gas and returning the captured liquid components into the crankcase.

  As this type of blow-by gas reduction device and blow-by gas filter, for example, those disclosed in Patent Document 1 are known. In the technique disclosed in Patent Document 1, blow-by gas is sucked from the head cover chamber (17c) communicated with the crankcase, and the liquid component removed through the two filters (21, 22) is returned to the intake system. I am letting.

  The oil and moisture separated and captured by the filtering action of the filters (21, 22) passes through the drain pipe (23) provided with a check valve from the bottom of the filter case (10), and is cranked by gravity. (16) It is configured to return to the inside.

JP 2007-247448 A

  By the way, in the filter for blow-by gas, inconvenience may occur due to clogging of the filter medium or engine start-up. That is, when the pressure (inflow side pressure) of the pre-filter portion upstream of the flow of blow-by gas with respect to the filter medium in the filter case increases due to the clogging or engine start-up, the pressure in the crankcase or the drain line (23) is increased. In some cases, the check valve at the upper end of the drain pipe is difficult or impossible to function, or the trapped liquid component cannot be returned to the crankcase.

  In such a case, liquid components such as oil may accumulate in the blow-by gas filter more than specified, or the filter medium may be soaked in the excessive liquid components, which may impair the filtration function. Therefore, the blow-by gas filter has room for further improvement so as not to cause the above-described disadvantage even when the inflow side pressure becomes high.

  An object of the present invention is to provide a blowby gas filter that is further improved by avoiding inconveniences caused by an increase in inflow side pressure, such as inability to return a liquid component such as oil and a decrease in filtration function, by structural improvements. There is in point to do.

The invention according to claim 1 includes a filter case 15B and a filter medium 15A accommodated therein, and a blowby gas provided in a blowby gas reduction passage w for returning the blowby gas in the crankcase 4 to the intake passage k. In the filter for
The filter case 15B is provided with a return port 15c to which a return path 17 communicating with the crankcase 4 can be connected at a post-filtering site r which is downstream in the blow-by gas flow direction with respect to the filter medium 15A. A check valve 21 having a check action from the return port 15c toward the post-filter site r is provided;
A short-circuit path 23 is formed that communicates the pre-filter portion f that is upstream in the blow-by gas flow direction with respect to the filter medium 15A in the filter case 15B and the upstream side in the check action direction of the check valve 21. It is characterized by.

The invention according to claim 2 is the blow-by gas filter according to claim 1,
The return port 15c is formed in the case bottom 15s of the filter case 15B, and the filter medium 15A is formed in a bottomed cylindrical shape in which the check valve 21 is provided at the bottom 22b,
When the filter medium 15A is disposed away from the case bottom 15s, the pre-filter part f that is the outer diameter of the filter medium 15A and the upstream side of the check valve 21 in the check action direction, The short-circuit path 23 that communicates is configured.

The invention according to claim 3 is the blowby gas filter according to claim 2,
The check valve 21 is swingably displaceable between a closed posture in contact with the bottom surface 28 of the bottom portion 22b and an open posture away from the bottom surface 28 in order to close the passage hole 27 formed in the bottom portion 22b. And it has the valve piece part 21a which elastically returns to the said closed position, It is characterized by the above-mentioned.

According to the first aspect of the present invention, the upstream side of the check valve in the non-return action direction and the front of the filter even if the pressure (inflow side pressure) of the pre-filter part increases due to clogging of the filter medium or engine start-up. Since the site communicates with the short circuit, a blow-by gas passage can be secured even if the pressure at the site before filtration increases.
Even if the liquid component accumulates too much in the post-filtering site due to the malfunction of the check valve such as freezing, the filter medium can flow backward when the engine is stopped and can flow from the pre-filter site through the short-circuit path to the return port.
Therefore, inconveniences that the liquid component accumulates more than specified and the filter medium is soaked and impedes the filtration function are avoided, and the check valve is difficult or impossible to function, or the captured liquid component Can not be returned to the crankcase.
As a result, it is possible to provide a blowby gas filter that is further improved so as to avoid inconveniences caused by an increase in inflow side pressure, such as an inability to return a liquid component such as oil and a decrease in filtration function, due to structural improvements. it can.

  According to the invention of claim 2, the short-circuit path is formed only by arranging the filter medium provided with the check valve at the bottom away from the case bottom of the filter case, that is, by changing the arrangement height of the filter medium. Therefore, for example, there is no need to specially devise such that a part of the case is bulged to provide a groove-like short circuit, and there is an advantage that the filter case can be easily manufactured.

  According to the invention of claim 3, the check valve can be configured to have a valve piece portion such as a rubber piece provided on the bottom surface of the bottom portion, and can be a simple check valve provided at the bottom portion of the filter medium. There are advantages that can be done.

Sectional drawing which shows the structure of the filter for blow-by gas (Embodiment 1) Schematic diagram showing blow-by gas reduction device Front view of diesel engine Left side view of the diesel engine in FIG. Plan view of the diesel engine of FIG. Right side view of the diesel engine in FIG. (A) Sectional drawing which shows the lower part of the filter for blow-by gas of a comparative example, (b) Main part sectional drawing of the filter for blow-by gas which shows another structure of a short circuit

  Below, the case where the embodiment of the filter for blow-by gas by this invention is applied to the blow-by gas reduction apparatus of a general purpose diesel engine is demonstrated, referring drawings.

Embodiment 1
A general-purpose diesel engine mounted on an agricultural tractor or the like is shown in FIGS. In this diesel engine, a cylinder head 2 is assembled to the upper part of the cylinder block 1, and an oil pan 3 is assembled to the lower part of the cylinder block 1. A crankcase 4 is formed at the lower part of the cylinder block 1, a cylinder (not shown) and a cylinder jacket (not shown) surrounding the cylinder block 1 are formed at the upper part, and an oil filter 5 is attached to the front left side of the cylinder block 1. It has been.

  As shown in FIGS. 3 to 6, an engine cooling fan 6 for the engine and a radiator (not shown) is disposed at the front of the engine (one end side of the crankshaft), and at the rear of the engine (the other end side of the crankshaft). A flywheel housing 7 that houses a flywheel (not shown) is disposed, and a cylinder head cover 8 is attached to the upper side of the cylinder head 2. The cylinder head cover 8 is equipped with a blow-by gas extraction part 9 and an oil injection cap 10. A turbo mechanism 12 communicating with the exhaust manifold 11 is provided on the side of the cylinder head 2 and a DPF device 13 is provided on the rear side of the engine.

  An intake manifold 14 is arranged on one side of the cylinder head 2, that is, on the left side of the engine, and a pressure passage 32 for supplying pressurized air from the turbo mechanism 12 is communicated with the intake manifold 14. . Further, a blow-by gas filter (hereinafter simply referred to as a filter) 15 of a blow-by gas reduction device A described later is provided on the left side of the engine.

  Next, the blow-by gas reducing device A will be described. As shown in FIG. 2, the blow-by gas reduction device A equipped in the diesel engine basically includes a blow-by gas reduction passage w connecting the cylinder head cover 8 and the intake passage k, and the blow-by gas reduction passage w. Are provided with a filter 15 and a return path 17 connecting the filter 15 and the cylinder block 1.

  As shown in FIGS. 1 and 2, the intake path k is a path that connects the air cleaner 18 and the cylinder head 2 and includes the intake manifold 14. The blow-by gas reduction passage w is formed to have a gas forward passage 19 for communicating the cylinder head cover 8 and the inlet portion 15a of the filter 15 and a gas return passage 20 for communicating the outlet portion 15b of the filter 15 and the intake passage k. ing. The return path 17 is formed by a conduit that communicates with the return port 15c of the filter 15 and the crankcase 4 (or the cylinder block 1).

  Although not shown in the drawing, an introduction path for guiding blow-by gas generated in the crankcase 4 into the cylinder head cover 8 is formed in the cylinder block 1. Therefore, the blow-by gas extraction part 9 from the engine is formed in the cylinder head cover 8. The blow-by gas generated in the crankcase 4 enters the filter 15 from the cylinder head cover 8 through the gas forward path 19, where the liquid component consisting of oil and moisture is removed, and the blow-by gas from which the liquid component has been removed is The gas is returned to the intake path k through the gas return path 20 and recombusted. The liquid component captured by the filter 15, mainly oil (engine oil), returns to the crankcase 4 through the return path 17 connected to the bottom of the filter case 15 </ b> B.

  Next, the filter 15 will be described. As shown in FIG. 1, the filter 15 removes a liquid component mainly composed of unburned gas (including moisture) from the blow-by gas, and an outlet portion from which the liquid component has been removed by the filter medium 15A. 15b can be taken out. Further, the removed liquid component is stored in the post-filter site r and is configured to be able to be discharged downward (see the broken arrow b in FIG. 1) from the lower return port 15c by gravity.

  As shown in FIG. 1, a filter case 15B, a filter medium 15A accommodated in the filter case 15B, a check valve 21 provided at the bottom of the filter medium 15A, a balance valve 16 provided at the top of the filter case 15B, and the like. And is provided in a blow-by gas reduction passage w for returning the blow-by gas in the crankcase 4 to the intake passage k.

  The filter case 15B has an inlet 15a for taking blow-by gas into the filter case 15B, an outlet 15b for taking out blow-by gas from which the liquid component has been filtered, and the liquid component captured by the filter medium 15A. A return port 15c for returning to the inside is formed. The filter case 15B includes a lower case 15k having a downward return port 15c, and an upper case 15j that includes a lateral inlet portion 15a and a lateral outlet portion 15b and can be screwed into the lower case 15k. . The return port 15c is formed so as to protrude further downward from a protruding case portion 15t that protrudes downward in a cylindrical shape from the case bottom 15s of the lower case 15k.

The filter medium 15A has a bottomed cylindrical shape including an inner peripheral cylinder 22a having a large number of holes (not shown) and a petri dish (petri dish) shape and a bottom plate (an example of a bottom portion) 22b having an inner flange. The filter body 22 and the upper lid 24 are housed in the filter case 15B in a vertically oriented posture with the diameter facing sideways.
That is, the blow-by gas that has entered from the inlet portion 15a passes through the filter medium 15A from the pre-filter site f, which is the space around the filter medium 15A in the filter case 15B, and enters the post-filter site r, which is the internal space of the filter medium 15A. 24 is configured to flow to the outlet portion 15 b through the outlet pipe portion 25 provided in the outlet 24.
The cylindrical and downward tube cover 15r is a member for diffusing the blow-by gas that has entered from the inlet portion 15a in the pre-filter site f.

  As shown in FIG. 1, the check valve 21 is mounted on the bottom plate 22b of the filter medium 15A, and closes in close contact with the bottom surface 28 of the filter medium 15A so as to close the passage hole 27 formed in the bottom plate 22b. It is configured to have a valve piece portion 21a that can swing and displace between a posture and an open posture away from the bottom surface 28, and that elastically returns to a closed posture.

A burring hole 26 and a plurality of passage holes 27 arranged concentrically around the burring hole 26 are formed in the center of the bottom plate 22b. The burring hole 26 has a valve body 21A made of a flexible material such as rubber. Are tightly fitted.
The valve body 21A includes a cylindrical portion 21b that is tightly fitted (or press-fitted) into the burring hole 26 so as to prevent it from coming off, and a circular valve piece portion 21a that extends along the bottom surface 28 of the bottom plate 22b. All the passage holes 27 are closed by the lid action of the valve piece 21a.

  By disposing the filter medium 15A away from the case bottom 15s upward, the pre-filter part f that is outside the diameter of the filter medium 15A, and the upstream side of the check valve 21 in the check action direction (arrow A in FIG. 1) Are connected to each other. For example, in FIG. 1, the upstream side of the check valve 21 in the check action direction is an inner portion 29 of the protruding case portion 15 t and a portion communicating with the return port 15 c. Further, for example, as shown in FIG. 1, the short circuit 23 is formed between the outer peripheral portion of the valve piece portion 21 a and the case bottom 15 s, that is, by an annular gap portion.

  That is, the check valve 21 mounted on the bottom plate 22b of the filter medium 15A allows the liquid component captured by the filter body 22 to move downward from the post-filter site r through the passage hole 27, and the valve piece 21a. Specifically, the valve exhibits a check action that does not allow movement in the direction of arrow A from the upstream side of the check action direction to the post-filtering site r from the inner portion 29 of the protruding case portion 15t.

  The liquid component (mainly engine oil) trapped by the filter medium 15A accumulates in the post-filter part r, and when it accumulates to a certain extent, due to its weight, the valve of the check valve 21 is shown in FIG. The piece 21a is oscillated and deformed downward, and is discharged downward through the passage hole 27. The liquid component discharged downward from the check valve 21 reaches the return port 15c through the inner portion of the protruding case portion 15t. As shown in FIG. 2, oil or the like is returned from the return port 15 c into the crankcase 4 through the return path 17.

  For example, the blow-by gas filter 15 ′ of the comparative example shown in FIG. 7A is the same as the filter 15 shown in FIG. 1 except that the configuration of the check valve 21 is different, and the bottom plate 22b of the filter medium 15A. The check valve 21 is accommodated in the projecting case portion 15t so as to straddle the valve, and the return valve 21 is located upstream of the check valve 21 in the check direction by a cap 31 made of an elastic material such as rubber fitted to the bottom plate 22b. The mouth 15c and the pre-filter site f are configured to be cut off.

  Therefore, the trapped liquid component is accumulated on the bottom plate 22b of the filter medium 15A to the height of the tip of the inner and outer flanges 30. In the winter season in northern countries, the accumulated liquid component is frozen and grows, and the filtered portion. There was a possibility that the passage from r to the check valve 21 would be blocked.

  In the blow-by gas reducing apparatus A according to the present invention shown in FIGS. 1 and 2, if the pressure at the pre-filtering part f is clearly higher than the post-filtering part r, the movement of the valve piece 21a becomes awkward and the check valve 21 becomes difficult to open, and even if oil or the like is accumulated too much in the post-filtering site r, the liquid component flows backward from the post-filtering site r to the pre-filtering site f when the engine is stopped. Then, it becomes possible to flow to the return path 17 (return port 15c).

Therefore, it is possible to avoid the occurrence of inconvenience that the filter medium 15A is impeded by the filter medium 15A being immersed in oil or the like that has accumulated more than a predetermined amount and the oil has accumulated too much. Of course, the inconvenience that the check valve 21 is difficult or impossible to function or the captured oil or the like cannot be returned into the crankcase 4 is avoided.
That is, in addition to the path that flows from the post-filter part r to the inner part 29 through the check valve 21, there are two paths that include a path that flows from the pre-filter part f to the inner part 29 through the short circuit 23.

As described above, in the filter 15 ′ (see FIG. 7 (a)) of the comparative example in which the passage from the filtered part r of the liquid component to the return port 15c is only the check valve 21 part, see FIG. It is conceivable that a slight amount of liquid component accumulated in the part r freezes and grows, and the passage to the return port 15c is blocked.
On the other hand, in the filter 15 according to the present invention in which the pre-filter site f and the check valve upstream side of the check valve 21 communicate with each other through the short circuit 23, inconvenience due to freezing does not occur in the structure or Not likely to occur. In addition, since the pulsation in the crankcase 4 is transmitted to the pre-filter part f and the post-filter part r via the short circuit 23, the vibration due to the pulsation hardly causes freezing itself or freezing growth. However, there is an advantage that the return path 17 is not blocked.

[Another embodiment]
For example, in the filter 15 ′ having the comparative example structure shown in FIG. 7A, as shown in FIG. 7B, the inner portion 29 of the protruding case portion 15t (the upstream side in the check action direction of the check valve 21). And a bypass-like short circuit 23 that communicates with the pre-filter part f on the upper side of the case bottom 15s may be provided.

  The check valve 21 may have a structure other than that shown in FIG. The short circuit 23 may be other than the annular one or the bypass one.

4 Crankcase 15A Filter medium 15B Filter case 15c Return port 15s Case bottom 17 Return path 21 Check valve 21a Valve piece part 22b Bottom part 23 Short circuit path 27 Passing hole 28 Bottom face f Filter part k Intake path r Filter part

Claims (3)

A filter for a blow-by gas having a filter case and a filter medium accommodated therein and provided in a blow-by gas reduction passage for returning the blow-by gas in the crank case to the intake passage,
The filter case in the filter case is provided with a return port to which a return path communicating with the crankcase can be connected at a post-filtering site downstream in the blow-by gas flow direction with respect to the filter medium. A check valve having a check action toward the site is provided,
For the blow-by gas in which a short-circuit path is formed which communicates the upstream portion in the check action direction of the check valve with the pre-filter portion upstream in the blow-by gas flow direction with respect to the filter medium in the filter case filter. The return port is formed in the case bottom of the filter case, and the filter medium is configured in a bottomed cylindrical shape in which the check valve is equipped at the bottom,
By arranging the filter medium away from the case bottom upward, the short-circuit path that communicates the pre-filter portion that is outside the diameter of the filter medium and the upstream side of the check valve in the check action direction. The blowby gas filter according to claim 1, wherein:   The check valve is swingable and displaceable between a closed posture in contact with the bottom surface of the bottom portion to close a passage hole formed in the bottom portion and an open posture away from the bottom surface, and is in the closed posture. The blow-by gas filter according to claim 2, wherein the blow-by gas filter is configured to have a valve piece portion that returns elastically.

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