JP4036185B2 - Engine oil separator - Google Patents

Description

  The present invention relates to an oil separation device for an engine.

  Normally, blow-by gas is generated in the crank chamber, which is the space between the cylinder block and the oil pan, as the engine burns inside. For this purpose, blow-by gas is returned to the intake system and burned. However, oil mist exists in the crank chamber (and the valve-operating chamber, which is a space between the cylinder head and the head cover, which is in communication with the blow-by gas). Therefore, it is necessary to separate the mixed oil components when returning to the intake system. If this separation is insufficient, the returned oil component may adversely affect the exhaust system catalyst.

  For this reason, as a prior art, it is known to arrange a so-called oil separator on the side wall of the cylinder block so that the oil separation chamber is interposed in a passage for returning blowby gas from the crank chamber to the intake system downstream of the throttle valve. (For example, Patent Document 1 below).

  It is also known to arrange an oil separator having an oil separation chamber in the head cover (for example, Patent Document 2 below).

Then, any of the oil separators of Patent Documents 1 and 2 below opens against the biasing force of the spring when the intake negative pressure exceeds a predetermined value in the passage returning the blowby gas from the oil separation chamber to the intake system downstream of the throttle valve. While a PCV valve is provided, a ventilation passage for introducing fresh air into a space where blow-by gas exists, for example, a valve operating chamber, communicates with an intake system upstream of the throttle valve.

  Thereby, the blow-by gas from which the oil component has been separated during a predetermined operation state, for example, idling or low / medium load operation, can be returned to the intake system. However, during high load operation, there is almost no intake negative pressure downstream of the throttle valve, and the PCV valve does not open. Rather, the pressure in the intake system upstream of the throttle valve becomes lower than the pressure in the valve chamber, and the oil in the valve chamber Blow-by gas containing mist is returned to the intake system through the ventilation passage, which is not preferable.

  For this reason, the first oil separator is arranged on the cylinder block side and the second oil separator is arranged on the cylinder head cover side. During idling and low / medium load operation, a throttle valve is inserted through the PCV valve from the first oil separator. The blow-by gas that has been oil-separated is returned to the intake system downstream of the valve and communicated with the intake system upstream of the throttle valve via the second oil separator to provide a ventilation passage when the first oil separator performs the oil separation function. Alternatively, the second oil separator may be allowed to perform an oil separation function during high load operation.

  By the way, the oil separator provided on the cylinder head cover side, as described in Patent Document 2 below, is an internal space extending in the longitudinal direction of the engine, and includes a ceiling wall portion of the cylinder head cover, a plurality of vertical wall portions, and these. It is formed by a plate-like baffle plate that is closed from below, and a blow-by gas introduction part and a blow-by gas lead-out part are provided on both end sides of the internal space, while a plurality of drain parts for returning the separated oil are provided.

  According to the literature 2, the opening of the drain part is blocked by oil, and blow-by gas does not leak from the valve chamber to the internal space. However, if the amount of accumulated oil is small, blow-by gas Leaks into the internal space, and the blow-by gas is returned to the intake system with almost no oil component removed, which is a problem to be solved.

  Therefore, a plurality of oil separation chambers extending in the longitudinal direction (in the cylinder row direction of the engine) are partitioned by a partition wall, a communication passage extending in the cylinder row direction of the engine is provided in the partition wall, and the crank chamber is operated during high engine load operation. An oil drain is provided only in the oil separation chamber on the most upstream side of the blow-by gas flow including oil mist flowing from the cylinder head to the valve operating chamber, etc., and the oil is separated in each oil separation chamber. When functioning as a ventilation passage in which fresh air flows in a direction opposite to the above flow, the communication passage is configured to return the oil accumulated in the other oil separation chambers to the adjacent oil separation chamber via the communication passage. For example, the opening facing the oil separation chamber upstream of the ventilation flow is By setting the opening facing the oil separation chamber on the downstream side of the ventilation flow at the upper position of the partition wall, the accumulated oil is moved downstream as needed, and finally the oil is It is conceivable to return to the oil separation chamber on the downstream side and return to the valve operating chamber and thus the crank chamber from the oil drain.

  However, when these oil separation chambers perform an oil separation function during high load operation, the oil separator interior can be maintained even if there is a difference in the height position of the opening through the communication path of the partition wall. The flow of blow-by gas that flows up and down as it moves from the upstream oil separation chamber to the adjacent downstream oil separation chamber becomes the main flow, and since the flow is relatively simple, it tends to be rectified as a whole. . Therefore, there is a problem that the oil may be taken out again on such a rectified flow, and the oil recovery efficiency cannot be improved.

JP 2002-106429 A Japanese Utility Model Publication No. 5-17110

  Accordingly, an object of the present invention is to improve oil separation performance from blow-by gas containing oil mist in an oil separation structure having a plurality of oil separation chambers in a cylinder head cover.

  The first configuration of the engine oil separation device according to the present invention is provided near the cylinder block of the engine, introduces blow-by gas containing oil mist in the crankcase, separates the oil, and opens and closes the blow-by gas with an on-off valve. First oil separation means for supplying the intake passage downstream of the throttle valve via the intake passage, and a blow-by gas including oil mist in the cylinder head cover, which is provided in the cylinder head cover, is introduced to separate the oil, and the blow-by gas is supplied to the intake passage. An oil separation device for an engine comprising a second oil separation means that can be supplied upstream of a throttle valve, wherein the second oil separation means is a cylinder partitioned vertically by a flat baffle plate in the cylinder axial direction of the engine It extends in the cylinder row direction of the engine above the inside of the head cover. Formed as an oil separation space, the oil separation space is divided into at least one partition wall and divided into a plurality of oil separation chambers, and a blowby gas introduction portion and an oil drain portion are provided in the oil separation chamber on one end side, A blow-by gas lead-out section is provided in the oil separation chamber on the other end side, and a communication passage is provided in the partition wall for communicating adjacent oil separation chambers, and blow-by gas is transferred from the blow-by gas introduction section to the blow-by gas lead-out section. A part of the upstream oil separation chamber that flows toward the downstream side is a recessed portion that is recessed toward the downstream oil separation chamber, and the communication path intersects the partition wall in the cylinder row direction of the engine in plan view. In addition, it is formed obliquely in the vertical direction so that the opening to the recess of the upstream oil separation chamber is higher than the opening to the downstream oil separation chamber. And those are.

  According to the first configuration, when the blow-by gas including the oil mist flows so as to be supplied from the crankcase side through the cylinder head and the second oil separation means in the cylinder head cover to the upstream of the throttle valve in the intake passage, The blow-by gas containing the oil mist component in the oil separation means flows toward the recess of the upstream oil separation chamber provided with the blow-by gas introduction portion, and then in the cylinder row direction of the engine in plan view with respect to the partition wall It flows in the communication passage that intersects with. Therefore, the flow direction is changed when entering the communication path from the depression, and the oil component easily collides with and adheres to the wall around the depression, so that the oil separation performance can be improved.

  In addition, according to the first configuration, since the opening facing the recessed portion of the upstream oil separation chamber is formed so as to be at a position higher than the opening to the downstream oil separation chamber, When the oil component in the gas exits from the opening on the outlet side of the communication path, the direction is changed again, and it becomes easy to efficiently adhere to the wall surface. Therefore, in combination with the first configuration, the oil separation performance can be improved in total.

  In the second configuration according to the present invention, the partition wall is formed integrally with the cylinder head cover, the opening to the oil separation chamber on the downstream side in the communication path is formed on the bottom surface of the partition wall, and the bottom surface and the opening of the partition wall are formed. At least one of the baffle plates that face the surface is formed with a recess communicating with the downstream oil separation chamber.

  According to the second configuration, blow-by gas introduced into the oil separation chamber on the downstream side from the communication path collides with the concave portion of the baffle plate or collides with the peripheral wall portion of the concave portion of the opening, further improving the oil separation performance. Can be made.

  Further, according to the second configuration, the partition wall is formed integrally with the cylinder head cover, whereby the surface rigidity of the cylinder head cover can be increased, and the communication path can be easily formed by drilling or the like.

  As described above, according to the present invention, in an oil separation structure having a plurality of oil separation chambers in a cylinder head cover, oil separation performance from blow-by gas containing oil mist can be enhanced.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  First, the outline of the engine according to the present invention will be described with reference to FIG. 1 which is a front view of the engine from the engine intake manifold side. The engine ENG is a so-called horizontal engine in which a plurality of cylinders (not shown) are arranged in the vehicle width direction so as to be arranged in the vehicle width direction, and a plurality of cylinders are arranged. Cylinder block CB, oil pan OP provided in the lower part of cylinder block CB, cylinder head H assembled on the upper surface of cylinder block CB via a gasket (not shown), and upper peripheral edge H1 of cylinder head H It is set as the structure provided with the cylinder head cover 1 assembled | attached to.

  An intake manifold IM is disposed on the vehicle front side of the engine ENG. The intake manifold IM is arranged downward and forward of the vehicle so as to bundle a plurality of intake manifold branch pipes IM1, IM2, IM3, and IM4 fixed to the surface portion of the cylinder head H on the vehicle front side. A surge tank part ST having a bulging shape and an upstream pipe UP extending from the surge tank part ST toward the upper rear side of the engine are further provided. The throttle body SB having the above is assembled.

  Further, a throttle upstream pipe FP formed of a flexible tube as an intake duct is connected to the upstream side of the throttle body SB, and an air cleaner box (not shown) is provided upstream of the throttle upstream pipe FP. It is connected.

  Further, a pipe member BP through which blow-by gas flows is provided from the rear surface of the cylinder head cover 1 and extends toward the front of the vehicle, and is then connected to the throttle upstream pipe FP and connected to the communication port BPH. Is formed.

  Next, the structure of the cylinder head cover will be described with reference to FIGS.

Here, FIG. 2 is a plan view and a front view of the cylinder head cover according to the present invention,
FIG. 3 is a bottom view of the cylinder head cover.
FIG. 4 is a perspective view of the baffle plate,
FIG. 5 is a diagram showing details of the Z portion in FIG.
FIG. 6 is a view showing a cross section AA in FIG.
FIG. 7 is a view showing a BB cross section in FIG. 6.

  2A is a plan view of the cylinder head cover 1, and FIG. 2B is a front view of the cylinder head cover 1. As shown in FIG. 2 (A), the cylinder head cover 1 is longer in the engine longitudinal direction (cylinder arrangement direction) than in the vehicle longitudinal direction, and the vehicle longitudinal direction width on the front side of the engine is larger than other parts. It has a slightly longer shape. This outer peripheral shape is substantially the same shape as the upper peripheral edge H1 of the cylinder head.

  That is, the cylinder head cover 1 is provided with a peripheral edge portion 11 having substantially the same shape as the upper peripheral edge portion H1 of the cylinder head around the lower portion, and a vertical wall portion 7a is erected from the peripheral edge portion 11 on the engine exhaust side. Is connected to a substantially horizontal exhaust side ceiling wall 7, a vertical wall 3 a is erected from a peripheral edge 11 on the front side of the engine, and an upper end thereof is connected to the engine front side ceiling wall 3, A vertical wall 5a is erected from the peripheral edge 11, and its upper end is connected to a substantially horizontal intake-side ceiling wall 5. The engine ENG in the present embodiment has a structure including an exhaust manifold (not shown) on the end face of the cylinder head on the vehicle rear side. Therefore, the exhaust-side ceiling wall portion 7 is provided with an exhaust valve driving camshaft SE (FIG. 6). The intake-side ceiling wall portion 5 is disposed above the intake valve driving camshaft SI (see FIG. 6).

  A vertical wall portion 7 b connected to the exhaust-side ceiling wall portion 7 and a vertical wall portion 5 b connected to the intake-side ceiling wall portion 5 are erected from the peripheral edge portion 11 on the rear side of the engine.

  The space between the exhaust side ceiling wall 7 and the intake side ceiling wall 5 is recessed toward the cylinder head, and the vertical wall 7c hangs down from the engine intake side end of the exhaust side ceiling wall 7 so that the intake side ceiling A vertical wall portion 5c hangs down from the engine exhaust side end portion of the wall portion 5, and the vertical wall portion 7 c and the lower end portion of the vertical wall portion 5 c are connected by an intermediate surface portion 9. The vertical wall portion 9a is also connected to the peripheral edge portion 11 from the engine rear side end portion of the intermediate surface portion 9, and the engine of the cylinder head cover 1 is constituted by the vertical wall portion 7b, the vertical wall portion 5b, and the vertical wall portion 9a. The rear vertical wall portion is integrally formed.

  An outlet pipe connecting portion 7 d connected to an L-shaped blowby gas outlet pipe (blowby gas outlet portion) 17 is provided on the engine rear side of the vertical wall portion 7 a of the exhaust-side ceiling wall portion 7. One end of the pipe member BP described with reference to FIG. 1 is connected to the end of the blow-by gas outlet pipe 17 on the rear side of the engine.

  On the other hand, an engine oil supply port 15 for injecting engine oil is provided on the engine front side of the exhaust side ceiling wall 7 and is normally closed by a cap member (not shown).

  In addition, a plurality of fastening portions 13 are provided on the peripheral edge portion 11. These fastening portions 13 are formed with bolt insertion holes (not shown), and the cylinder head cover 1 is assembled to the cylinder head H with a plurality of bolts.

  Note that the height of the exhaust-side ceiling wall portion 7 is formed higher than the height of the intake-side ceiling wall portion 5 (see FIG. 6), and the engine front-side ceiling wall portion 3 includes the exhaust-side ceiling wall portion 7 and the intake-side ceiling. The wall 5 is gently inclined so as to connect the front side of the engine.

  The external appearance of the cylinder head cover 1 has been described above. The cylinder head cover 1 is made of, for example, an aluminum alloy integrally formed by die casting, but may be made of a magnesium alloy or a synthetic resin. However, the material is not particularly limited.

  Next, the back surface structure of the cylinder head cover 1 with the baffle plate assembled will be described with reference to FIG.

  As shown in FIG. 3, the engine front side ceiling wall portion 3, the intake side ceiling wall portion 5, and the exhaust side ceiling wall portion 7 of the cylinder head cover 1 have ribs R extending in the engine longitudinal direction and in a direction perpendicular thereto. Are formed, and the rigidity of the cylinder head cover 1 is ensured.

  A plurality of partition walls W1 (hereinafter referred to as the first partition wall W1) and W2 (hereinafter referred to as the second partition wall W2) arranged in the longitudinal direction of the engine are connected to the valve operating chamber 75 (see FIG. 6). (See) side.

  The first partition wall W1 and the second partition wall W2 are integrally formed so as to connect the vertical wall portion 7a connected to the ceiling wall portion 7 and the vertical wall portion 7c, respectively (see FIG. 6). ), And the connecting portion with the vertical wall portion 7a is provided on the engine front side with respect to the connecting portion with the vertical wall portion 7c. This is to collect blowby gas containing oil mist or oil accumulated on the baffle plate in the first partition wall W1 or a specific portion in the vicinity of the second partition wall W2. This will be described separately with reference to FIG. Note that the first partition wall W1 and the second partition wall W2 have the same structure.

  Further, the first partition wall W1 and the second partition wall W2 extend from the ceiling wall portion 7 to a substantially middle portion in the vertical direction of the vertical wall portion 7a and the vertical wall portion 7c, and have a flat bottom surface portion WB ( (See FIG. 5).

  A baffle plate 21 that is long in the longitudinal direction of the engine is in contact with and fixed to the bottom surface portion WB. Here, the structure of the baffle plate 21 will be described with reference to FIG.

  According to FIG. 4, the baffle plate 21 has a peripheral edge portion 23 in which a rear end portion of the engine is obliquely cut and a notch portion 25 is formed in the front-rear direction and slightly in the front portion. A blow-by gas introducing portion 27 is provided so as to protrude from the inner end of the plate to the oil separating portion (oil separating space) 70 side.

  The blow-by gas introducing portion 27 includes three surfaces of the standing surface portion 29 and one surface thereof is opened, and the oil separation chamber side end portions of these three surfaces are integrally connected by an upper surface portion 29a. Accordingly, the blow-by gas containing oil mist passes through the oil separation portion (oil separation space) through one surface opened from the space portion 27a surrounded by the three surfaces of the standing surface portion 29 from the valve operating chamber 75 side or the notch portion 25. ) Flows to the 70 side.

  On the inner side of the plate of the peripheral portion 23, the first concave portions 31a, 31b, 31c, and 31d that are recessed from the peripheral portion 23 toward the valve operating chamber 75 side, and the second recess that is also recessed toward the valve operating chamber 75 side. Recesses 33a and 33b are formed.

  The first concave portion 31a is provided on the engine front side with respect to the blow-by gas introduction portion 27, and the first concave portions 31b, 31c, and 31d are formed at a predetermined interval on the engine rear side with respect to the blow-by gas introduction portion 27.

  The second recess 33a is continuously recessed from the front end of the first recess 31c toward the valve operating chamber 75, and is provided on the rear side of the baffle plate 21 in the vehicle longitudinal direction, that is, on the engine exhaust side. ing. The engine front side end of the second recess 33a and the engine rear side end of the first recess 31b are spaced apart from each other with a predetermined width.

  The second recess 33b is continuously recessed from the front end of the first recess 31d toward the valve operating chamber 75, and is located on the rear side of the baffle plate 21 in the vehicle front-rear direction, that is, on the engine exhaust side. Is provided. The engine front side end of the second recess 33b and the engine rear side end of the first recess 31c have a predetermined width and are separated from each other.

  The baffle plate 21 has a plurality of screw hole portions 35 formed in the peripheral edge portion 23. The baffle plate 21 is formed on the bottom surface portion WB of the first partition wall W1 and the second partition wall W2 in the cylinder head cover 1. And a screw member (not shown) is inserted into the screw hole 35 from the valve operating chamber 75 side, and the vertical wall portion 7a and the vertical wall portion 7c of the cylinder head cover 1, and the first partition wall W1 and the second partition. Fastened to wall W2. Specifically, as shown in FIG. 6, the peripheral portion 23 of the baffle plate 21 is installed on the stepped portion 7e formed on the vertical wall portion 7a and the vertical wall portion 7c of the cylinder head cover 1 and fastened with a screw member. It has become.

  The baffle plate 21 is preferably a press-formed product of a steel plate from the viewpoint of securing the rigidity of the cylinder head cover-1, but is not limited thereto.

  3 and 6, the stepped portion 7e and the bottom surface portion WB of the first partition wall W1 and the second partition wall W2 are assumed to be in the same continuous surface.

  Further, the stepped portion 7e is also provided at the engine front portion and the rear portion. That is, the stepped portion 7 e is formed on the cylinder head cover 1 so as to face the peripheral portion 23 of the baffle plate 21 and the cutout portion 25 in the peripheral portion 23.

  Therefore, as shown in FIG. 3, when the baffle plate 21 is brought into contact with the stepped portion 7e of the cylinder head cover 1, the bottom surface portion WB of the first partition wall W1, and the bottom surface portion WB of the second partition wall W2, and fastened, An oil separation part 70 (see FIG. 8) sandwiched between the ceiling wall part 7 and the baffle plate 21 is formed, and the oil separation part 70 is further partitioned into three chambers from the engine front side. Structure.

  These three chambers are a first oil separation chamber P1, a second oil separation chamber P2, and a third oil separation chamber P3 from the front side of the engine.

  The first oil separation chamber P1 includes a ceiling wall portion 7, a vertical wall portion 7a, a vertical wall portion 7c, and a baffle plate 21 in a range from the step portion 7e on the engine front side of the cylinder head cover 1 to the first partition wall W1. It is a space partitioned by.

  The first oil separation chamber P1 and the valve operating chamber 75 communicate with each other through the notch 25, and a blow-by gas containing oil mist is introduced from the valve operating chamber 75 to the first oil separation chamber P1. Further, the notch 25 has a function of dropping the oil accumulated in the first oil separation chamber P1 into the valve operating chamber 75 at the same time.

  The second oil separation chamber P2 is a space partitioned by the ceiling wall portion 7, the vertical wall portion 7a, the vertical wall portion 7c, and the baffle plate 21 in the range from the first partition wall W1 to the second partition wall W2. .

  The blow-by gas containing oil mist is introduced through a communication passage 41 (see FIG. 5 and others, described in detail later) formed in the first partition wall W1, and is cooled in the second oil separation chamber P2 to be blow-by gas. Some oil is separated from

  The third oil separation chamber P3 includes a ceiling wall portion 7, a vertical wall portion 7a, a vertical wall portion 7c, and a baffle plate 21 in a range from the second partition wall W2 to the step portion 7e on the engine rear side of the cylinder head cover 1. It is a partitioned space.

  The blow-by gas from which part of the oil mist has been removed in the second oil separation chamber P2 is the same as the communication path 41 (not shown; the communication path 41 formed in the first partition wall W1) formed in the second partition wall W2. And is introduced through the third oil separation chamber P3, and the oil is almost completely separated from the blow-by gas, and the blow-by gas is discharged from the blow-by gas outlet pipe 17. The

  Next, the structure in the vicinity of the first partition wall W1 will be described with reference to FIGS. In FIG. 5, hatched portions are stepped portions 7e provided on the vertical wall portions 7a and 7c of the cylinder head cover 1, and a bottom surface portion WB of the first partition wall W1, and the baffle plate 21 is an imaginary line. Is shown. The second partition wall W2 has the same structure as the first partition wall W1 as shown in FIG.

  First, as shown in FIG. 6, the step portion 7e is formed at a substantially intermediate height position between the vertical wall portion 7a and the vertical wall portion 7c of the cylinder head cover 1, and the baffle plate 21 abuts against the surface of the step portion 7e. It is concluded in a state. Further, as described above, the surface of the stepped portion 7e and the bottom surface portion WB of the first partition wall W1 are in the same continuous surface.

  As shown in FIG. 5, the first partition wall W <b> 1 has a predetermined width in the longitudinal direction of the engine and extends from the ceiling wall portion 7. That is, the predetermined width of the first partition wall W1 includes the engine front side inclined portion W1f extending from the ceiling wall portion 7 and facing the first oil separation chamber P1, and the second oil second extending from the ceiling wall portion 7 as well. The width in the engine front-rear direction with respect to the engine rear side inclined portion W1r facing the oil separation chamber P2, and becomes narrower as it approaches the baffle plate 21 side.

  And the 1st recessed parts 31b and 31c of the baffle plate 21 are provided in the state which does not contact the surface of the step part 7e, and the 1st partition wall W1.

  The second recess 33a, which is formed continuously from the end of the first recess 31c on the front side of the engine and further recessed toward the valve operating chamber 75, is a position where the front side of the engine faces the bottom surface WB of the first partition wall W1. However, as shown in FIGS. 6 and 7, a gap S is provided between the second recess 33a and the bottom surface portion WB. Further, the engine rear side of the second recess 33a extends to the second oil separation chamber P2, and the vehicle rear side of the second recess 33a also extends to the second oil separation chamber P2.

  Further, as shown in FIG. 2, a protruding portion 19 is formed on the engine intake side of the ceiling wall portion 7. The projecting portion 19 includes a ceiling surface portion 19a, an inclined surface portion 19b inclined toward the front of the engine so as to connect the ceiling surface portion 19a to the ceiling wall portion 7, an engine rear side end portion of the ceiling surface portion 19a, and the ceiling wall portion 7 A trapezoidal box-shaped space 19c as viewed in the vehicle front-rear direction is formed by the rear wall portion 19d, the vertical wall portion 7c, and the engine front side inclined portion W1f (see FIGS. 6 and 7). . That is, the space portion 19c is a part of the first oil separation chamber P1, and is a hollow portion that is recessed toward the second oil separation chamber P2 (see FIG. 7).

  A communication passage 41 is formed in the bottom surface portion WB of the first partition wall W1 facing the second recess 33a from the engine front side inclined portion W1f close to the ceiling surface portion 19a of the protruding portion 19. That is, the communication passage 41 has an opening 41b in the engine front side inclined portion W1f near the ceiling surface portion 19a of the projecting portion 19, and the opening 41a in the bottom surface portion WB of the first partition wall W1 facing the second recess 33a. It has an inclined communication path. Further, a counterbore portion 43 is formed on the bottom surface portion WB where the opening 41a opens, and the opening area is increased (see FIG. 6).

  The structure in the vicinity of the first partition wall W1 that partitions the first oil separation chamber P1 and the second oil separation chamber P2 has been described above. Next, FIG. 5 shows the flow of blow-by gas including oil mist from the first oil separation chamber P1 to the second oil separation chamber P2, and the flow of oil from the second oil separation chamber P2 to the first oil separation chamber P1. This will be described with reference to FIGS.

  Note that the flow of blow-by gas varies depending on the engine operating state, and includes oil mist when the engine ENG is fully loaded, that is, when the opening of the throttle valve SV is fully open or relatively large. The blow-by gas flows from the first oil separation chamber P1 to the second oil separation chamber P2, and further from the second oil separation chamber P2 to the third oil separation chamber P3. The separated blow-by gas is discharged. On the other hand, when the engine ENG is in partial load operation, that is, when the opening degree of the throttle valve SV is relatively small, the flow is reverse to that in full load operation, and the separated oil flows from the third oil separation chamber P3. It flows into the second oil separation chamber P2, further flows from the second oil separation chamber P2 to the first oil separation chamber P1, and falls from the notch 25 of the baffle plate 21 to the valve operating chamber 75. The flow during full load operation and partial load operation of the engine ENG will be described separately based on FIG.

  5, 6, and 7, white arrows indicate the flow of blow-by gas including oil mist during full load operation, and black arrows indicate oil separated from blow-by gas including oil mist during partial load operation. It shows the flow.

As described above, the first oil separation chamber P1 and the valve operating chamber 75 communicate with each other through the notch 25 of the baffle plate 21, and blow-by gas containing oil mist is transferred from the valve operating chamber 75 to the first oil separation chamber. The structure is introduced into P1. Accordingly, during full load operation of the engine ENG, the blow-by gas including the oil mist introduced from the valve operating chamber 75 is first in the first oil separation chamber P1 as shown in FIG. 5 or FIG. 1 It flows toward the engine front side inclined part W1f of the partition wall W1, and a part of it collides with the engine front side inclined part W1f.
Subsequently, the air flows toward the space 19c that is recessed toward the second oil separation chamber P2 along the engine front side inclined portion W1f.

  The blow-by gas including the oil mist reaching the vicinity of the space 19c of the protrusion 19 contacts the ceiling surface portion 19a, the inclined surface portion 19b, the rear wall portion 19d, and the vertical wall portion 7c as the surrounding wall members. As a result, part of the oil mist adheres to these wall members as an oil component, and drops and accumulates in the flat plate portion 21a of the baffle plate 21 or the first recess 31b.

  The blow-by gas containing a part of the oil mist then enters the communication path 41 with its flow direction greatly changed. That is, as can be seen from FIG. 6, the flow once toward the projecting portion 19 is directed from the opening 41b of the communication passage 41 toward the counterbore portion 43 of the opening 41a provided in the bottom surface portion WB of the first partition wall W1. Going down. As can be seen from FIGS. 5 and 7, the blow-by gas including a part of the oil mist from the first oil separation chamber P1 toward the second oil separation chamber P2 (that is, from the engine front side to the engine rear side) is Change the flow to the engine exhaust side at a substantially right angle.

  Due to this sudden change in the flow direction, the blow-by gas including a part of the oil mist easily collides with the rear wall portion 19d and the inner wall (not indicated) of the communication passage that forms the space portion 19c of the protruding portion 19, and as a result, The oil can be easily separated from the oil mist, and the oil separation performance is enhanced.

  The blow-by gas including part of the oil mist that has passed through the communication path 41 in this way passes through the gap S formed between the bottom surface portion WB of the first partition wall W1 and the second recess 33a, so that the second oil Although it flows into the separation chamber P2, it collides with the surface portion of the second recess 33a of the baffle plate 21 due to the directivity due to the inclination of the communication passage 41, and the oil component (oil mist) in the blow-by gas is second. It adheres to the recess 33a, and the oil separation performance is enhanced.

  On the other hand, at the time of partial load operation of the engine ENG, as shown by the black arrow, the oil accumulated in the flat plate portion 21a and the first recess 31c of the baffle plate 21 in the second oil separation chamber P2 is sucked into the intake negative pressure (FIG. 8) and the fresh air entering from the blow-by gas outlet pipe 17 flows toward the engine front side, that is, toward the engine rear side inclined portion W1r of the first partition wall W1, and as shown in FIG. In addition, since the engine rear side inclined portion W1r is formed in a step shape so as to face the engine front side, the oil is collected in the second recess 33a that is formed to be deepest toward the valve operating chamber 75 side. Become.

  Eventually, the oil will collect in the entire depression of the second recess 33a, but it will take the flow of fresh air from the relationship with the intake negative pressure and further head toward the first oil separation chamber P1 on the front side of the engine. To do. As a result, the oil flows back up through the inclined communication passage 41 and rises, falls from the lower portion 41c of the opening 41b facing the space 19c of the protruding portion 19 to the first oil separation chamber P1, and the first oil in the first oil separation chamber P1. If it accumulates in the recessed part 31b and the flat plate part 21a and the accumulated quantity increases, it will fall into the valve operating chamber 75 from the notch part 25. FIG. As can be seen from FIG. 7, the bottom surface portion WB of the partition wall W1 on the first oil separation chamber P1 side from the communication passage 41 is in contact with the flat plate portion of the baffle plate 21 and fastened in the vicinity thereof. , There is no gap.

  Therefore, according to the present invention, the cutout portion 25 formed in the vicinity of the introduction portion 27 for introducing blow-by gas containing oil mist from the valve operating chamber 75 is also configured to return separated oil to the valve operating chamber. For example, a structure in which an oil drain portion is separately provided in the third oil separation chamber P3 on the rear side of the engine may not be employed.

  In addition, since the flow of blow-by gas containing oil mist is suddenly changed, the gas collides with the wall member around the passage and is cooled, so that the oil separation performance is improved.

  The flow of blow-by gas including oil mist from the second oil separation chamber P2 to the third oil separation chamber P3 and the flow of oil from the third oil separation chamber P3 to the second oil separation chamber P2 are the same. The explanation is omitted.

  In this embodiment, two partition walls are provided so as to form three oil separation chambers. However, a structure such as three partition walls provided so as to form four oil separation chambers may be used.

  Subsequently, the conditions under which the oil separation performance as described above is effectively exhibited are shown in FIG. 1 from the viewpoint of the engine operating state, and FIG. 8 showing a cross-sectional view in the front-rear direction of the engine ENG in the CC section of FIG. Based on In the following description, the second oil separation means is formed in the cylinder head including the first oil separation chamber P1, the second oil separation chamber P2, and the third oil separation chamber P3 that have been described so far. This is the oil separation unit 70, which is hereinafter referred to as second oil separation means 70. Further, in FIG. 8, illustrations of valve operating system parts such as the camshaft SE and pistons are omitted.

  First, the front-rear direction sectional structure of the engine ENG in the CC section of FIG. 2 will be described with reference to FIG. The structure of the cylinder head cover 1 and the baffle plate 21 described so far will be omitted. A valve operating chamber 75 provided on the cylinder head H is connected to a cylinder head oil drain passage 77, and a lower end portion of the cylinder head oil drain passage 77 extends in the engine vertical direction in the cylinder block CB. The upper end of the passage 81 communicates with a gasket (not shown).

  The lower end of the cylinder block oil drain passage 81 is desired in a crank chamber 83 formed in the lower part of the cylinder block CB, and an oil pan OP for storing engine oil is assembled in the lower part thereof.

  On the other hand, the first oil separation means 91 is provided in the cylinder block CB on the engine intake side where the intake manifold IM is assembled.

  The first oil separating means 91 is provided above the crank chamber 83, and a recess 87 formed integrally with the cylinder block CB so as to cover a cylinder liner CL in which a piston (not shown) reciprocates up and down its inner periphery. And a cover member 89 and a plurality of baffle plates (partially indicated by reference numeral 91a) formed in the cylinder block CB or the cover member 89 so as to form a labyrinth-like passage inside.

  For example, blow-by gas containing oil mist, which will be described later, collides with the baffle plate portion 91a and the like to attach the oil mist as droplets, and the mist formation is promoted in the process of moving through the labyrinth path to become droplets. The oil is dropped into the oil pan OP.

  A well-known PCV valve is connected to the upper portion of the first oil separating means 91. Although this PCV valve is not specifically illustrated in the figure, it is normally closed by the biasing force of the spring, but when the intake negative pressure exceeds a predetermined value, the PCV valve is opened against the biasing force. It will be.

  Although not shown in FIG. 8, a pipe member 95 (see FIG. 1) is connected to the upper portion of the PCV valve, and the other end of the pipe member 95 is closer to the upstream pipe UP side of the surge tank ST, that is, the suction. It is connected to a connecting portion 93 provided in the upstream portion of the air.

  Accordingly, when the PCV valve is opened, the blow-by gas from which the oil mist has been removed by the first oil separation means 91 is guided to the surge tank ST, and then passes through the plurality of intake manifold branch pipes IM1 and the like. It is introduced into the combustion chamber.

  By the way, such a flow of blow-by gas is made different depending on the engine operating state. First, during partial load operation of the engine ENG, that is, when the opening degree of the throttle valve SV is relatively small, when the intake negative pressure becomes high and the PCV valve opens, the first oil separation means 91 performs the oil separation function. At this time, as described with reference to FIG. 1, one end of the pipe member BP communicates with the communication port BPH of the throttle upstream pipe FP, and the other end communicates with the second oil separating means 70 of the cylinder head cover 1. Therefore, fresh air sucked through an air cleaner box (not shown) is guided from the communication port BPH of the throttle upstream pipe FP to the second oil separation means 70 through the pipe member BP. In FIG. 8, the flow of fresh air is indicated by an arrow in the upper right hatching.

  The fresh air guided to the second oil separation means 70 flows to the crank chamber 83 via the valve operating chamber 75, the cylinder head oil drain passage 77, and further the cylinder block oil drain passage 81 in the cylinder block CB. Will go.

  That is, the oil accumulated in the third oil separation chamber P3 of the second oil separation means 70 rides on the flow of fresh air flowing from the blow-by gas outlet pipe 17 and passes through the communication passage 41 of the second partition wall W2. The oil flows into the second oil separation chamber P2, and further flows along with the oil accumulated in the second oil separation chamber P2 through the communication passage 41 of the first partition wall W1 to the first oil separation chamber P1. The oil falls into the chamber 75 and is stored in the oil pan OP through the cylinder head oil drain passage 77 and the cylinder block oil drain passage 81.

  Thus, the fresh air is guided to the crank chamber 83 while returning the oil of the second oil separating means 70 to the valve operating chamber 75 and the oil pan OP, but the oil mist in the valve operating chamber 75 and the oil pan OP The oil mist is entrained and flows to the first oil separating means 91 formed in the cylinder block CB together with the blow-by gas accumulated in the crank chamber 83. The flow of fresh air, blow-by gas, and oil mist is indicated by white arrows.

  As described above, the oil mist adheres and condenses in the baffle plate portion 91a and the like until it reaches the PCV valve, and falls into the oil pan OP, but the remaining fresh air and blow-by gas The mixed fluid (upper left hatched arrow) is provided on the upstream pipe UP side of the surge tank ST, that is, on the upstream side of the intake air through the pipe member 95 (see FIG. 1) by the opening operation of the PCV valve. It reaches the connecting portion 93 and is finally introduced into the engine combustion chamber.

  On the other hand, when the engine ENG is in full load operation, that is, when the opening of the throttle valve SV is fully open or relatively large, the flow of blow-by gas is opposite to that during partial load operation. That is, during full load operation, the intake negative pressure decreases downstream of the throttle valve SV and the internal pressure of the crank chamber 83 increases. As a result, the throttle valve is compared with the crank chamber 83 and the second oil separator 70. When the pressure in the throttle upstream pipe FP on the upstream side of SV becomes a low pressure state, the blow-by gas flows from the crank chamber 83 through the first oil separating means 70 toward the upstream of the throttle valve SV.

  In this case, the flow of blow-by gas is indicated by black arrows in FIG. That is, blow-by gas leaking from the engine combustion chamber flows from the crank chamber 83 into the valve operating chamber 75 through the cylinder block oil drain passage 81 and the cylinder head oil drain passage 77. At this time, the oil mist in the crank chamber 83 also flows toward the valve operating chamber 75 along the flow of blow-by gas, and part of the oil mist is in the cylinder block oil drain passage 81 and the cylinder head oil drain passage. While passing through 77, the oil adhering to these wall surfaces or absorbed into the crank chamber 83 is absorbed.

  The blow-by gas and the oil mist flowing into the valve operating chamber 75 are added with the oil mist generated by driving the valve operating parts, and the second oil is separated through the blow-by gas introducing portion 27 (see FIGS. 3 and 4). Flows to means 70.

  The blow-by gas containing the oil mist that has flowed into the second oil separation means 70 through the blow-by gas introduction portion 27 is communicated from the first oil separation chamber P1 of the second oil separation means 70 to the first partition wall W1. Through the second oil separation chamber P2 and further through the communication passage 41 of the second partition wall W2 to the third oil separation chamber P. In the process, the oil is almost separated into blowby gas. The exit part 17 is reached.

  Accordingly, the blow-by gas discharged from the blow-by gas outlet portion 17 to the pipe member BP is blow-by gas from which oil mist is almost separated and removed (the flow is indicated by an arrow in the upper left hatch). It flows into the communication port BPH of the throttle upstream pipe FP connected to the other end of the pipe member BP, and is introduced from the hold IM into the engine combustion chamber between the intake air downstream of the throttle valve SV.

  As described above, the separation performance of the oil mist from the blowby gas including the oil mist in the second oil separation means 70 has been described while showing the relationship with the engine operating conditions. However, according to the gist of the present invention, the performance of the engine of the present invention is described. The oil separation device is not limited to the above embodiment.

The front view which shows the engine which concerns on this invention from the engine intake manifold side Plan view and front view of cylinder head cover according to the present invention Bottom view of cylinder head cover Baffle plate perspective view The figure which shows the detail of the Z section in FIG. The figure which shows the AA cross section in FIG. The figure which shows the BB cross section in FIG. The figure which shows the engine front-back direction cross section in CC section of FIG. 2 (The figure which shows the flow of the blow-by gas in an engine)

Explanation of symbols

1 ... Cylinder head cover 17 ... Blow-by gas outlet pipe (Blow-by gas outlet)
19c ... space (indentation)
21 ... Baffle plate 25 ... Oil drain part 27 ... Blow-by gas introduction part 33a, 33b ... 2nd recessed part (recessed part)
41 ... Communication passage 41a ... Opening (opening to the oil separation chamber on the downstream side)
41b ... Opening (opening to the recess of the upstream oil separation chamber)
70 ... second oil separation means (oil separation space)
91: First oil separating means W1, W2: Partition wall P1: Oil separation chamber P2 on one end side: Oil separation chamber P3: Oil separation chamber ENG on the other end side: Engine CB ... Cylinder block SV ... Throttle valve

Claims (2)

First oil separating means provided near the cylinder block of the engine, for introducing a blow-by gas containing oil mist in the crankcase, separating the oil, and supplying the blow-by gas downstream of the throttle valve in the intake passage through the on-off valve When,
A second oil separation means provided in the cylinder head cover, capable of introducing blow-by gas including oil mist in the cylinder head cover, separating oil and supplying the blow-by gas upstream of the throttle valve in the intake passage; An engine oil separator,
The second oil separation means includes
Formed as an oil separation space extending in the cylinder row direction of the engine above the inside of the cylinder head cover partitioned by a flat baffle plate vertically in the cylinder axis direction of the engine,
The oil separation space is divided into at least one partition wall and divided into a plurality of oil separation chambers,
A blow-by gas introduction part and an oil drain part are provided in the oil separation chamber on one end side, while a blow-by gas lead-out part is provided in the oil separation chamber on the other end side,
The partition wall is provided with a communication path for communicating adjacent oil separation chambers,
A part of the upstream oil separation chamber in which blow-by gas flows from the blow-by gas introduction portion toward the blow-by gas lead-out portion is a hollow portion that is recessed toward the downstream oil separation chamber direction,
The communication path intersects the partition wall in the cylinder row direction of the engine in a plan view, and the opening to the recessed portion of the upstream oil separation chamber is higher than the opening to the downstream oil separation chamber An oil separation device for an engine, wherein the oil separation device is formed so as to be inclined in the vertical direction so as to be positioned.   2. The partition wall according to claim 1, wherein the partition wall is formed integrally with the cylinder head cover, and an opening to the oil separation chamber on the downstream side in the communication path is formed on the bottom surface of the partition wall, and the bottom surface of the partition wall and the An oil separation device for an engine, wherein a recess communicating with the downstream oil separation chamber is formed in at least one of the baffle plates facing the opening.

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