Head cover, internal combustion engine and vehicle

Abstract

To provide a head cover capable of recovering oil included in blow-by gas as much as possible.SOLUTION: A head cover of an internal combustion engine includes a baffle chamber partitioned between a ceiling part and a plate. The baffle chamber includes: a first chamber in which part of oil mist is retained and separated from blow-by gas flowing in through a blow-by gas inlet; a second chamber that has a wall for guiding and returning back the blow-by gas that has passed through an outlet of the first chamber and in which oil mist is separated from the blow-by gas; a third chamber that has a curved surface wall for guiding and turning the blow-by gas that has passed through the second chamber and in which oil mist is separated from the blow-by gas; and a restriction part that reduces an opening area toward an outlet of the third chamber in the second chamber.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a head cover, an internal combustion engine, and a vehicle. [Background technology]

[0002] For example, Patent Document 1 discloses a head cover attached to an internal combustion engine. This head cover is provided with an oil separator that separates oil from blow-by gas containing oil mist. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-143628 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a head cover, an internal combustion engine, and a vehicle that can recover as much oil as possible contained in blow-by gas. [Means for solving the problem]

[0005] According to one aspect of the present invention, a head cover for an internal combustion engine comprises a head cover body having a ceiling portion, and a plate arranged opposite the ceiling portion, a baffle chamber defined between the ceiling portion and the plate, and a blow-by gas inlet provided in the plate for allowing blow-by gas containing oil mist to flow into the baffle chamber. The baffle chamber has: a first chamber that retains and separates a portion of the oil mist from the blow-by gas that flows in through the blow-by gas inlet; a second chamber that is connected to the downstream side of the first chamber along the direction in which the blow-by gas flows and has a wall that guides the blow-by gas that has passed through the outlet of the first chamber in a turning manner, and separates the oil mist from the blow-by gas; a third chamber that is connected to the downstream side of the second chamber along the direction in which the blow-by gas flows and has a curved wall that guides the blow-by gas that has passed through the second chamber in a swirling manner, and separates the oil mist from the blow-by gas; a throttling portion in the second chamber that reduces the opening area toward the outlet of the third chamber; and a blow-by gas outlet that is connected to the downstream side of the third chamber along the direction in which the blow-by gas flows and discharges the blow-by gas. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a head cover, an internal combustion engine, and a vehicle that can recover as much oil as possible contained in blow-by gas. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a top view of the mounting state of the internal combustion engine relative to the front-rear and left-right directions of the vehicle. FIG. [Figure 2] 1 is a cross-sectional view showing a part of an internal combustion engine including a head cover and a part of a cab provided above the engine. [Figure 3] FIG. 3 is a schematic perspective view of a head cover of the internal combustion engine shown in FIGS. 1 and 2; [Figure 4] 4 is a bottom view of the head cover as seen from the direction indicated by the arrow IV in FIG. 3. [Figure 5] FIG. 4 is a perspective view of the head cover shown in FIG. 3 as seen from the right side. [Figure 6] FIG. 6 is a schematic perspective cross-sectional view of the head cover taken along line VI-VI in FIG. 4. [Figure 7] FIG. 7 is a schematic perspective cross-sectional view of the head cover taken along line VII-VII in FIG. 4. [Figure 8] 8 is a schematic perspective cross-sectional view of the head cover as viewed from the direction indicated by the reference symbol VIII in FIG. 5. FIG. [Figure 9] 6 is a schematic perspective cross-sectional view of the head cover as viewed from the direction indicated by the reference symbol IX in FIG. 5. [Figure 10] 5 is a perspective view of the bottom wall portion of the head cover shown in FIG. 4. FIG. [Figure 11] FIG. 9 is an enlarged view of the position indicated by the symbol XI in FIG. 8. [Figure 12] FIG. 9 is an enlarged view of the position indicated by the symbol XII in FIG. 8. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present embodiment will be described below with reference to the accompanying drawings. The directions of up, down, front, back, left, and right shown in the drawings are defined merely for the convenience of explanation.

[0009] Fig. 1 shows a view from above of the mounting state of the internal combustion engine 12 in the longitudinal and lateral directions of the vehicle 10. Fig. 2 shows a cross-sectional view showing a part of the internal combustion engine 12 including the head cover 30 and a part of the cab (cabin) 14 provided above the internal combustion engine 12. Note that Fig. 2 is a cross-sectional view taken along line II-II in Fig. 4. The head cover 30 is disposed on the upper part of the internal combustion engine 12.

[0010] FIG. 3 shows a schematic perspective view of a head cover 30 of the internal combustion engine 12.

[0011] Fig. 4 shows a bottom view of the head cover 30 as seen from the direction indicated by arrow IV in Fig. 3. Fig. 5 shows a perspective view of the head cover 30 shown in Fig. 3 as seen from the left side.

[0012] Fig. 6 shows a schematic perspective cross-sectional view of the head cover 30 taken along line VI-VI in Fig. 4. Fig. 7 shows a schematic perspective cross-sectional view of the head cover 30 taken along line VII-VII in Fig. 4.

[0013] 8 and 9 are cross-sectional views taken along line SS in Fig. 5. Therefore, Fig. 8 and Fig. 9 show the head cover 30 with the top part removed. Fig. 8 shows a schematic perspective cross-sectional view of the head cover 30 as viewed from the direction indicated by reference symbol VIII in Fig. 5. Fig. 9 shows a schematic perspective cross-sectional view of the head cover 30 as viewed from the direction indicated by reference symbol IX in Fig. 5.

[0014] Fig. 10 shows a see-through view of the bottom wall portion (plate) 42 of the head cover 30 shown in Fig. 4. Fig. 11 shows an enlarged view of the position indicated by reference character XI in Fig. 8. Fig. 12 shows an enlarged view of the position indicated by reference character XII in Fig. 8.

[0015] As shown in Figures 1 and 2, a vehicle 10 according to this embodiment includes an internal combustion engine 12 and a cab 14 provided above the internal combustion engine 12. Reference numeral 14a in Figure 2 denotes a floor panel. That is, the vehicle 10 according to this embodiment is formed as a cab-over type in which the cab 14 is disposed above the internal combustion engine 12. It is preferable that the internal combustion engine 12 of such a vehicle 10 has an internal combustion engine main body 22 and a head cover 30, which will be described later, formed as low in height as possible.

[0016] 2, the distance L1 between the floor panel 14a and the head cover main body 32 of the head cover 30 is, for example, about 34 mm. Also, the distance L2 between the floor panel 14a and the head cover main body 32 of the head cover 30 is, for example, about 81 mm.

[0017] Behind the cab 14, a bodywork (for example, a loading platform) is arranged.

[0018] The schematic configuration of an internal combustion engine 12 will be described with reference to Figure 1. In Figure 1, outline arrows A indicate the flow of intake air, solid arrows G indicate the flow of exhaust gas, and dotted arrows B indicate the flow of blow-by gas.

[0019] The internal combustion engine 12 of this embodiment is a multi-cylinder compression ignition internal combustion engine mounted on a vehicle 10, for example, a six-cylinder diesel engine having six cylinders and pistons, indicated by reference numeral 12a in Fig. 2. The vehicle 10 is, for example, a large vehicle such as a truck. However, there are no particular limitations on the type, model, or use of the vehicle 10 and the internal combustion engine 12. For example, the vehicle 10 may be a small vehicle such as a passenger car, and the internal combustion engine 12 may be a spark ignition internal combustion engine such as a gasoline engine.

[0020] The internal combustion engine 12 includes an internal combustion engine body 22 , an intake passage 24 , an exhaust passage 26 , a turbocharger 28 , and a head cover 30 .

[0021] The internal combustion engine body 22 includes fixed parts such as a cylinder head, a cylinder block, and a crankcase, and movable parts housed therein such as a piston, a crankshaft, and a valve mechanism. A head cover 30 that covers the valve mechanism is fixed to the top of the cylinder head. In other words, the internal combustion engine body 22 is provided with the head cover 30.

[0022] The intake passage 24 includes an intake manifold 24a connected to the cylinder head of the internal combustion engine body 22, and an intake pipe 24b connected to the upstream end of the intake manifold 24a.

[0023] The intake manifold 24a distributes air sent from an intake pipe 24b to the intake ports of each cylinder. In the intake pipe 24b, an air cleaner 24c, a compressor 28a of a turbocharger 28, and an intercooler 24d are provided in this order from the upstream side.

[0024] The exhaust passage 26 includes an exhaust manifold 26a connected to the cylinder head of the internal combustion engine body 22, and an exhaust pipe 26b arranged downstream of the exhaust manifold 26a.

[0025] The exhaust manifold 26a collects the exhaust gases sent from the exhaust ports of each cylinder. A turbine 28b of a turbocharger 28 is provided between the exhaust manifold 26a and an exhaust pipe 26b.

[0026] A blow-by gas passage through which blow-by gas flows is provided inside the internal combustion engine body 22. The blow-by gas is gas that leaks into the crankcase from the gap between the cylinder and the piston.

[0027] The blow-by gas passage, for example, passes from inside the crankcase through the cylinder block and the cylinder head and communicates with the inside of the head cover 30 .

[0028] As shown in FIG. 2, the head cover 30 is provided with a head cover main body 32 that is above the cylinder head of the internal combustion engine 12 and covers the vicinity of the top of the internal combustion engine 12, and an oil separator 34 that is provided in the head cover main body 32 and has a baffle chamber 70 for separating oil contained in blow-by gas.

[0029] As shown in FIGS. 3 to 10, the head cover body 32 of the head cover 30 is formed to be elongated in the front-rear direction relative to the left-right direction, for example, and to have an appropriate height.

[0030] The inner wall portion 33 of the head cover main body 32 is recessed upward and, together with the oil separator 34, forms a space for separating oil from oil-containing blow-by gas. The inner wall portion 33 has a ceiling portion 33a formed with a gently curved surface that is preferably flat, approximately flat, or close to approximately flat, and its outer periphery is formed as a peripheral wall portion 33b that mainly defines the height (spatial height) of the ceiling portion 33a inside the head cover main body 32 relative to the upper end of the internal combustion engine body 22.

[0031] The height of the head cover 30 is set by appropriately setting the thickness of the ceiling portion 33a of the head cover main body 32, the thickness of the peripheral wall portion 33b, and the height of the peripheral wall portion 33b.

[0032] A large number of polygonal ribs 33c, for example, are formed on substantially the entire surfaces of the ceiling portion 33a and peripheral wall portion 33b of the inner wall portion 33 of the head cover main body 32. The presence of the ribs 33c allows the head cover main body 32 to be thin-walled while maintaining appropriate strength. In this embodiment, the ribs 33c are rhombic, but they may also be regular polygons such as regular hexagons or regular octagons, and the shape can be selected appropriately.

[0033] A seal portion 33d is provided on the outer edge of the inner wall portion 33 of the head cover main body 32, closing the gap between it and the internal combustion engine main body 22. The seal portion 33d is positioned so as to avoid the bolts that secure the head cover main body 32 to the internal combustion engine main body 22. Furthermore, it is preferable that protrusions 64a, 64b, 64c, and 64d on the other side wall 64, which will be described later, are adjacent to the positions where the bolt holes 33e are arranged.

[0034] An outlet pipe (blow-by gas outlet) 36 of the blow-by gas passage is provided in the head cover body 32. The outlet pipe 36 of the blow-by gas passage of the head cover 30 is connected to an external oil separator filter (not shown), and the blow-by gas passes through the filter and a return passage (not shown) inside the head cover 30, and is then connected to the upstream end of a blow-by gas pipe 38.

[0035] The blow-by gas pipe 38 is a pipe member for returning blow-by gas to the intake pipe 24b. The blow-by gas pipe 38 is made of a resin material such as rubber, and is disposed outside the internal combustion engine 12. The downstream end of the blow-by gas pipe 38 is connected to a gas inlet 24e formed in the intake pipe 24b. The gas inlet 24e is provided in the intake pipe 24b located between the air cleaner 24c and the compressor 28a.

[0036] For this reason, in this embodiment, while the internal combustion engine 12 is running, the blow-by gas in the crankcase flows in this order through the blow-by gas passage in the internal combustion engine body 22, the oil separator 34 in the head cover 30, the outlet pipe 36 of the blow-by gas passage in the head cover 30, the external oil separator filter, the return passage in the head cover 30, and the blow-by gas pipe 38, and is introduced into the intake pipe 24b from the gas inlet 24e. The blow-by gas introduced into the intake pipe 24b is sent to the compressor 28a together with the intake air from the air cleaner 24c.

[0037] In addition, the blow-by gas may be configured to flow in order through the blow-by gas passage of the internal combustion engine body 22, the oil separator 34 of the head cover 30, the outlet pipe 36 of the blow-by gas passage of the head cover 30, the external oil separator filter, and the blow-by gas pipe 38, and then be discharged to the outside of the vehicle 10.

[0038] The head cover main body 32 includes an oil discharge portion 40. The oil discharge portion 40 is disposed, for example, at a low position on the left rear end portion of the head cover main body 32.

[0039] 5 to 9, the oil separator 34 is formed in a position close to the ceiling portion 33a of the inner wall portion 33 of the head cover main body 32. The oil separator 34 separates oil from blow-by gas. The oil separated from the blow-by gas is returned to the crankcase of the internal combustion engine main body 22 through the oil discharge portion 40 and an oil return pipe (not shown).

[0040] 4 to 10, the oil separator 34 includes a bottom wall portion 42 that faces the ceiling portion 33a of the inner wall portion 33 of the head cover main body 32, and an oil collection wall 46 that is provided between the bottom wall portion 42 and the ceiling portion 33a of the inner wall portion 33 of the head cover main body 32. The peripheral wall portion 33b of the inner wall portion 33 of the head cover main body 32, together with the bottom wall portion 42, forms a surrounding wall 33b1 that defines the oil separator 34.

[0041] The bottom wall portion 42 includes a flat portion 52 and an oil collecting portion 54 that is located lower than the flat portion 52. The flat portion 52 and the oil collecting portion 54 are formed to be longer in the front-rear direction than in the left-right direction.

[0042] 2, when the internal combustion engine 12 is attached to the vehicle 10, the flat surface 52 is arranged so that the front side is inclined upward and the rear side is inclined downward compared to the front side at an angle α (for example, several degrees) with respect to the horizontal plane. As an example, the inclination angle α is 4°. Furthermore, when the internal combustion engine 12 is attached to the vehicle 10, the flat surface 52 is arranged so that the right side is inclined upward and the left side is inclined downward compared to the right side with respect to the horizontal plane. As an example, the inclination angle of the flat surface 52 is 4°.

[0043] Although an example in which the left side is inclined downward relative to the right side will be described here, it is also preferable that the right side is inclined downward relative to the left side depending on the position of the oil discharge portion 40.

[0044] A blow-by gas inlet 56 is provided at a position on the rear end side of the flat portion 52 and forward of the rearmost end. The oil separator 34 has an inlet 56 for a blow-by gas passage to the head cover 30.

[0045] The blow-by gas inlet 56 has an opening in the flat surface portion 52. Below the opening, a generally U-shaped guide wall 56a is provided to guide the blow-by gas into the oil separator 34 while preventing the blow-by gas from entering the oil separator 34 in a straight line. In this embodiment, the blow-by gas is guided by the guide wall 56a in a horizontal direction (for example, from right to left) below the flat surface portion 52 and enters the baffle chamber 70. The guide wall 56a of the blow-by gas inlet 56 prevents engine oil in the internal combustion engine body 22 from being stirred up and directly entering the baffle chamber 70. In this embodiment, the oil collection portion 54 is disposed on the left side of the flat portion 52. The oil collection portion 54 has a first surface 54a and a second surface 54b. The first surface 54a and the second surface 54b are formed in a substantially rectangular shape. For example, the right end of the first surface 54a is continuous with the left end of the flat portion 52. The first surface 54a is inclined downward and leftward relative to the flat portion 52. The right end of the second surface 54b is continuous with the left end of the first surface 54a. The second surface 54b is parallel to the flat portion 52 or inclined upward and leftward relative to the first surface 54a. The second surface 54b is inclined downward and leftward near the oil discharge portion 40. The oil discharge portion 40 is located lower than the second surface 54b.

[0046] Due to the inclination of the flat surface 52 of the bottom wall 42 in the front-to-back and left-to-right directions and the oil collection section 54, oil is guided toward the oil discharge section 40 through the flat surface 52 of the bottom wall 42 of the oil separator 34 and the oil collection section 54.

[0047] For example, oil supplied from the flat surface portion 52 to the oil recovery portion 54 is basically collected at the boundary between the first surface 54a and the second surface 54b. Openings 85d, 85e (see FIGS. 11 and 12) that allow oil to flow rearward are formed in the 2-1 wall 84a and the 2-3 wall 84c (described later) near the boundary between the first surface 54a and the second surface 54b.

[0048] The surrounding wall 33b1 includes a pair of side walls 62, 64 extending in the front-rear direction, a front wall 66 connecting the front ends of the side walls 62, 64, and a rear wall 68 connecting the rear ends of the side walls 62, 64. The surrounding wall 33b1 is arranged in the shape of, for example, a substantially rectangular frame as a whole.

[0049] Of the side walls 62, 64, one side wall 62 is formed to extend straight in, for example, the front-rear direction. Of the side walls 62, 64, the other side wall 64 extends, for example, in the front-rear direction, but has protrusions 64a, 64b, 64c, and 64d at multiple locations that protrude into the inside of the baffle chamber 70. When the blow-by gas containing oil mist passes through each of the protrusions 64a, 64b, 64c, and 64d, the flow velocity of the blow-by gas containing oil mist increases.

[0050] The inner area defined by the surrounding wall 33b1, the bottom wall portion 42, and the ceiling portion 33a of the inner wall portion 33 of the head cover main body 32 is used as a baffle chamber 70 that separates oil from blow-by gas.

[0051] The oil recovery wall 46 is provided to connect the bottom wall portion 42 and the inner wall portion 33 of the head cover main body 32. The oil recovery wall 46 is preferably formed integrally with the ceiling portion 33a of the inner wall portion 33 of the head cover main body 32. The oil recovery wall 46 divides the baffle chamber 70 into a plurality of chambers (a first chamber 72, a second chamber 74, and a third chamber 76) so that the baffle chamber 70 has a labyrinth structure.

[0052] In this embodiment, the baffle chamber 70 has a first chamber 72, a second chamber 74, and a third chamber 76, arranged from the rear side (the inlet side of the blow-by gas), which is the upstream side of the blow-by gas, to the front side (the outlet side of the blow-by gas), which is the downstream side of the blow-by gas.

[0053] The first chamber 72 is provided at a position where the blow-by gas flows directly into the first chamber 72 from the blow-by gas inlet 56 .

[0054] The oil collection wall 46 of the first chamber 72 has a first wall (first wall portion) 82 extending from one side wall 62 toward the other side wall 64. The first wall 82 preferably extends substantially straight in the left-right direction. One end of the first wall 82 is fixed to or integrated with one of the side walls 62, and the other end is located near the boundary between the flat portion 52 and the first surface 54a of the oil collection portion 54. It is preferable that the other end of the first wall 82 is actually located on the first surface 54a of the oil collection portion 54.

[0055] The blow-by gas inlet 56 is provided in the bottom wall portion 42 between the first wall 82 of the first chamber 72 and the rear side wall 68. Therefore, the blow-by gas flows into the first chamber 72.

[0056] The other end of the first wall 82 is formed to form an opening (gap) 82a between it and the other side wall 64. That is, the opening 82a between the other end of the first wall 82 and the other side wall 64 is formed as an outlet of the first chamber 72 for blow-by gas and also as an inlet of the second chamber 74 for blow-by gas.

[0057] The protrusion 64a is provided on the first room 72 side of an imaginary extension line of the surface of the first wall 82 on the first room 72 side.

[0058] An oil discharge portion 40 that communicates with an oil return pipe is disposed adjacent to the protrusion 64a on the rear side wall 68 side. The oil discharge portion 40 is adjacent to the second surface 54b and is formed as an opening that discharges oil from the head cover main body 32.

[0059] The second chamber 74 is formed to guide the blow-by gas containing oil mist that has passed through the outlet of the first chamber 72 so that it moves substantially horizontally rearward with the momentum that caused the gas to move substantially horizontally forward relative to the outlet of the first chamber 72 along the wall, thereby separating the oil mist from the blow-by gas. That is, the second chamber 74 is formed to guide the blow-by gas so that it turns back, thereby lengthening the path of the blow-by gas and separating the oil mist. In this embodiment, the second chamber 74 is formed to guide the blow-by gas containing oil mist that has passed through the outlet of the first chamber 72 and is heading forward, along the wall in a horizontal direction, for example, approximately 180° relative to the outlet of the first chamber 72, thereby separating the oil mist from the blow-by gas.

[0060] In this embodiment, the second room 74 includes a 2-1 room 74a and a 2-2 room 74b.

[0061] The 2-1 room 74a has a 2-1 wall (second wall portion) 84a extending from the other side wall 64 toward the one side wall 62.

[0062] One end of the 2-1 wall 84a is fixed to or integrated with the other side wall 64. The 2-1 wall 84a includes an extending portion 85a extending in the left-right direction, for example, in the shape of a flat plate, a curved portion 85b bending from the other end of the extending portion 85a toward the rear first wall 82, and a flat plate portion (oil mist capturing portion) 85c provided continuous with the rear end of the curved portion 85b and extending, for example, in the shape of a flat plate toward the other side wall 64. That is, the flat plate portion 85c is provided on the first chamber 72 side with respect to the curved portion 85b. The 2-1 wall 84a has a substantially J-shaped appearance.

[0063] The extension 85a of the 2-1 wall 84a divides the first surface 54a and the second surface 54b of the oil collection portion 54 into front and rear portions. An opening 85d is formed in the extension 85a of the 2-1 wall 84a near the boundary between the first surface 54a and the second surface 54b of the oil collection portion 54. This opening 85d is used to allow oil to flow toward the oil discharge portion 40 on the rear side wall 68 side.

[0064] The curved surface portion 85b is formed as a curved wall that is bent horizontally by approximately 90 degrees toward the rear end side of the other end of the extending portion 85a. Therefore, the blow-by gas introduced into the second chamber 74 from the outlet of the first chamber 72, i.e., the inlet of the second chamber 74, is bent horizontally by approximately 180 degrees.

[0065] One end of the flat plate portion 85c is formed at the other end of the curved surface portion 85b. The flat plate portion 85c protrudes leftward from the other end of the curved surface portion 85b. Therefore, the flat plate portion 85c blocks the flow of blow-by gas that is introduced into the second chamber 74 from the outlet of the first chamber 72, i.e., the inlet of the second chamber 74, and guided along the extension portion 85a and the curved surface portion 85b. Therefore, the flat plate portion 85c captures oil from the blow-by gas. The other end of the flat plate portion 85c is located closer to the side wall 62 than the other end of the first wall 82.

[0066] The protruding portion 64b is provided closer to the first room 72 than the extending portion 85a of the 2-1st wall 84a.

[0067] It is preferable that the protruding portion 64b be disposed closer to the extending portion 85a of the 2-1st wall 84a than the flat plate portion 85c.

[0068] A passage for flowing blow-by gas downstream is formed between the other end (free end) of the flat plate portion 85c of the 2-1 wall 84a and the first wall 82 on the rear side (toward the rear side wall 68) of the flat plate portion 85c of the 2-1 wall 84a. Furthermore, the 2-1 chamber 74a forms a passage for flowing blow-by gas downstream between one side wall 62 and the curved surface portion 85b of the 2-1 wall 84a.

[0069] The oil collection wall 46 of the second chamber 74 has a 2-2 wall 84b extending from one side wall 62 toward the other side wall 64. The 2-2 wall 84b is located closer to the front wall 66 than the extension portion 85a of the 2-1 wall 84a. One end of the 2-2 wall 84b is fixed to or integrated with one side wall 62, and the other end is located near the boundary between the flat portion 52 and the first surface 54a of the oil collection portion 54. The other end of the 2-2 wall 84b is formed to form an opening (gap) 84b1 between it and the other side wall 64. Therefore, the 2-1 chamber 74a forms a passage for flowing blow-by gas downstream between the 2-2 wall 84b and the extension portion 85a and curved portion 85b of the 2-1 wall 84a.

[0070] The 2-2 wall 84b forms the boundary between the 2-1 room 74a and the 2-2 room 74b.

[0071] The 2-2 room 74b has a 2-3 wall (second wall portion) 84c extending from the other side wall 64 toward the one side wall 62. One end of the 2-3 wall 84c is fixed to or integrated with the other side wall 64. The 2-3 wall 84c is located closer to the front wall 66 than the 2-2 wall 84b. Similar to the 2-1 wall 84a, the 2-3 wall 84c includes an extending portion 85a extending in a flat plate shape in the left-right direction, a curved portion 85b bending from the other end of the extending portion 85a toward the first wall 82 on the rear side, and a flat portion 85c provided at the rear end of the curved portion 85b and extending in a flat plate shape toward the other side wall 64. The 2-3 wall 84c has a generally J-shaped appearance.

[0072] The extension 85a of the second-third wall 84c also covers the first surface 54a and the second surface 54b of the oil collection portion 54. An opening 85e is formed in the extension 85a of the second-third wall 84c near the boundary between the first surface 54a and the second surface 54b of the oil collection portion 54. This opening 85e is used to allow oil to flow toward the rear side wall 68.

[0073] The protruding portion 64c is provided closer to the first chamber 72 than the extending portion 85a of the 2-3 wall 84c.

[0074] The space between the other end of the 2-3 wall 84c and the other side wall 64 is formed as an outlet of the 2-2 chamber 74a.

[0075] At the other end of the second-third wall 84c, a wall portion (third wall portion) 86 is provided, which approaches one of the side walls 62 toward the front wall 66 on the front end side, and which, together with the one of the side walls 62, the ceiling portion 33a of the head cover main body 32, and the flat portion 52 of the bottom wall portion 42, forms a nozzle portion (throttled portion) that discharges blow-by gas downstream. That is, the second chamber 74 has the wall portion 86 that faces the outlet of the second chamber 74 along the direction in which the blow-by gas flows. The nozzle portion reduces the opening amount (opening area) of the passage through which the blow-by gas flows toward the outlet of the second chamber 74.

[0076] The portion of the wall portion 86 on the front wall 66 side serves as both the entrance to the third chamber 76 and the exit to the second chamber 74. The entrance to the third chamber 76 is formed so that the opening decreases from the second chamber 74 toward the third chamber 76.

[0077] The third chamber 76 is provided between the bottom wall 42 and the ceiling 33a and communicates with the downstream side of the nozzle section along the flow direction of the blow-by gas. The third chamber 76 guides the oil mist that has passed through the second chamber 74 along the wall so that it swirls approximately horizontally from the outlet of the nozzle section by 180° or more but less than 360°, thereby separating the oil mist. In this embodiment, in order to discharge oil, the third chamber 76 preferably has a curved wall 88 that guides the blow-by gas so that it swirls between 180° or more and approximately 270° horizontally from the outlet of the nozzle section (throttled section). In this embodiment, the curved wall 88 of the third chamber 76, together with one side wall 62 and the front wall 66 on the front end side, swirls the blow-by gas by approximately 270°. The curved wall 88 is provided in the third chamber 76 at a position closer to the right side than the left side. One end of the curved wall 88 is located on one side wall 62. The other end of the curved wall 88 is located rearward of the front end of the wall portion 86 formed as the nozzle portion. One end of the curved wall 88 is fixed to or integrated with one of the side walls 62 and the front side wall 66.

[0078] In this embodiment, the swirl angle of the blow-by gas caused by the curved wall 88 is set to 180° to 270°. However, the swirl angle of the curved wall 88 can be set appropriately, for example, up to nearly 360°, as long as the oil adhering to the inside of the curved wall 88 flows out into the oil recovery portion 54 through the flat portion 52 due to the inclination angle α of the flat portion 52 in the front-to-rear direction relative to the horizontal plane and the inclination angle α of the flat portion 52 in the left-to-right direction relative to the horizontal plane. Therefore, the curved wall 88 does not have to be a closed tube, and it is sufficient that the oil can be discharged to the outside of the curved wall 88.

[0079] The protruding portion 64d is disposed at a position facing the curved wall 88. An outlet pipe (blow-by gas outlet) 36 is provided in front of the protruding portion 64d. That is, the outlet pipe 36, which discharges blow-by gas, communicates with the downstream side of the third chamber 76 along the flow direction of the blow-by gas and discharges the blow-by gas.

[0080] Next, the operation of the oil separator 34 according to this embodiment will be described.

[0081] As shown in Fig. 10, when blow-by gas containing oil mist is introduced into the first chamber 72 from the blow-by gas inlet 56 of the baffle chamber 70, the introduced blow-by gas containing oil mist remains in the first chamber 72. Some of the oil mist adheres to the ceiling portion 33a, the first wall 82, the side walls 62, 64, the rear side wall 68, and the bottom wall portion 42 of the first chamber 72, respectively, and is separated from the blow-by gas. That is, an appropriate amount of oil mist is captured in the first chamber 72. Most of the oil mist captured here is heavy and has a relatively large particle size (average particle size) among the oil mist contained in the blow-by gas.

[0082] The oil then adheres to and is trapped on the ceiling 33a, first wall 82, side walls 62, 64, rear wall 68, and bottom wall 42 of the first chamber 72. Due to the slope shown in FIG. 2, the oil trapped in the first chamber 72 is collected at the boundary between the bottom wall 42 and rear wall 68 and guided to the first surface 54a, and then flows toward the oil discharge portion 40 through the boundary between the first surface 54a and the second surface 54b. In addition, some of the oil trapped on the side wall 64 flows directly toward the oil discharge portion 40.

[0083] The blow-by gas containing oil mist enters the 2-1 chamber 74 a through the outlet of the first chamber 72 , that is, the inlet of the second chamber 74 .

[0084] At this time, the protrusion 64a located upstream of the 2-1 chamber 74a narrows the spatial cross section in the left-right direction compared to a position further upstream of the 2-1 chamber 74a. Also, the spatial cross section (gap) in the left-right direction between the other end of the first wall 82 and the other side wall 64 is further narrowed. Therefore, the flow velocity of the blow-by gas increases and it passes through the gap between the other end of the first wall 82 and the other side wall 64 from the first chamber 72 to enter the 2-1 chamber 74a.

[0085] The blow-by gas collides with the flat plate portion 85c through the extension portion 85a and the curved portion 85b of the 2-1 wall 84a. At this time, the protrusion portion 64b reduces the spatial cross section (gap) in the left-right direction between the other side wall 64 and the curved portion 85b, thereby guiding the blow-by gas toward the curved portion 85b and causing the blow-by gas to collide with the flat plate portion 85c while maintaining an appropriate flow velocity. As a result, some of the oil mist contained in the blow-by gas adheres to the ceiling portion 33a, the side wall 64, the extension portion 85a, the curved portion 85b, and the flat plate portion 85c of the 2-1 wall 84a, and further to the bottom wall portion 42 of the 2-1 chamber 74a, and is separated from the blow-by gas. At this time, the blow-by gas collides with the flat plate portion 85c, i.e., the oil mist collides with the flat plate portion 85c, so that an appropriate amount of oil mist is captured in the 2-1 chamber 74a. Most of the oil mist captured in the 2-1 chamber 74 a has an average particle size smaller than that of the oil mist captured in the first chamber 72 .

[0086] Due to the inclination of the flat portion 52 in the front-to-back direction at an angle α relative to the horizontal plane and the inclination of the flat portion 52 in the left-to-right direction relative to the horizontal plane, some of the oil captured in the 2-1 chamber 74a is collected at the boundary between the flat portion 52 of the bottom wall portion 42 and the first wall 82, and is guided to the first surface 54a, and then flows toward the oil discharge portion 40 through the boundary between the first surface 54a and the second surface 54b.

[0087] After colliding with the flat portion 85c of the 2-1 wall 84a, the blow-by gas passes through the gap between the flat portion 85c and the first wall 82 toward the side wall 62, and then passes through the gap between the side wall 62 and the curved portion 85b of the 2-1 wall 84a, the gap between the 2-2 wall 84b and the curved portion 85b of the 2-1 wall 84a, and the gap between the 2-2 wall 84b and the extension portion 85a of the 2-1 wall 84a, and enters the 2-2 chamber 74b.

[0088] At this time, the spatial cross section (gap) in the left-right direction between the other end of the 2-2 wall 84b and the other side wall 64 is narrower than the gap between the 2-2 wall 84b and the curved surface portion 85b of the 2-1 wall 84a. Therefore, the blow-by gas flows from the 2-1 chamber 74a to the 2-2 chamber 74b through the gap between the other end of the 2-2 wall 84b and the other side wall 64 at a higher flow rate than when the blow-by gas flows between the 2-2 wall 84b and the curved surface portion 85b of the 2-1 wall 84a.

[0089] The blow-by gas collides with the flat plate portion 85c through the extension portion 85a and the curved portion 85b of the second-third wall 84c. At this time, the protrusion portion 64c reduces the spatial cross section (gap) in the left-right direction between the other side wall 64 and the curved portion 85b, thereby guiding the blow-by gas toward the curved portion 85b and causing the blow-by gas to collide with the flat plate portion 85c while maintaining an appropriate flow velocity. As a result, some of the oil mist contained in the blow-by gas adheres to the ceiling portion 33a, the side wall 64, the extension portion 85a, the curved portion 85b, and the flat plate portion 85c of the second-third wall 84c, and further to the bottom wall portion 42 of the second-second chamber 74b, and is separated from the blow-by gas. At this time, the blow-by gas collides with the flat plate portion 85c, i.e., the oil mist collides with the flat plate portion 85c, so that an appropriate amount of oil mist is captured in the second-second chamber 74b. Most of the oil mist captured in the 2-2 chamber 74b has an average particle size smaller than that of the oil mist captured in the first chamber 72 and the 2-1 chamber 74a.

[0090] Due to the inclination of the flat portion 52 in the front-to-back direction at an angle α relative to the horizontal plane and the inclination of the flat portion 52 in the left-to-right direction relative to the horizontal plane, some of the oil captured in the 2-2 chamber 74b is collected at the boundary between the flat portion 52 of the bottom wall portion 42 and the extension portion 85a of the 2-1 wall 84a, and is guided to the first surface 54a, and then flows toward the oil discharge portion 40 through the opening 85d at the boundary between the first surface 54a and the second surface 54b.

[0091] After colliding with the flat plate portion 85c of the 2-3 wall 84c, the blow-by gas passes between the flat plate portion 85c and the 2-2 wall 84b toward the side wall 62, passes between the side wall 62 and the curved surface portion 85b of the 2-3 wall 84c, and passes between the side wall 62 and the wall portion 86, which form the nozzle portion, and enters the third chamber 76. At this time, the flow path cross section between the side wall 62 and the wall portion 86 decreases from the upstream side to the downstream side, so the flow velocity of the blow-by gas increases.

[0092] The blow-by gas then moves along the curved wall 88. It then flows toward the outlet pipe 36 of the blow-by gas passage through the gap between the open end of the curved wall 88 and the wall portion 86, between the curved wall 88 and the curved portion 85b of the second-third wall 84c, and between the curved wall 88 and the extended portion 85a of the second-third wall 84c. That is, a portion of the oil mist contained in the blow-by gas moves while swirling horizontally along the curved wall 88, and thus an appropriate amount of the oil mist is captured in the third chamber 76 by utilizing the centrifugal force caused by the swirling blow-by gas. Therefore, oil is efficiently separated from the blow-by gas. Most of the oil mist captured in the third chamber 76 has a smaller average particle size than the oil mist captured in the first chamber 72, the second-first chamber 74a, and the second-second chamber 74b. Therefore, as the oil mist contained in the blow-by gas flows from the upstream side to the downstream side of the oil separator 34, i.e., through the first chamber 72, the 2-1 chamber 74a, and the 2-2 chamber 74b in that order, the average particle size of the oil mist captured in each chamber becomes gradually smaller.

[0093] Then, due to the inclination of the flat portion 52 in the front-to-back direction at an angle α relative to the horizontal plane and the inclination of the flat portion 52 in the left-to-right direction relative to the horizontal plane, some of the oil captured in the third chamber 76 is collected at the boundary between the flat portion 52 of the bottom wall portion 42 and the extension portion 85a of the second-third wall 84c, and is guided to the first surface 54a, and then flows toward the oil discharge portion 40 through the opening 85e at the boundary between the first surface 54a and the second surface 54b.

[0094] In this way, with the head cover 30 including the oil separator 34 of this embodiment, the blow-by gas containing oil moves through each of the chambers 72, 74, 76 in order, and the oil contained in the blow-by gas adheres to the walls of each of the chambers 72, 74, 76, allowing as much oil as possible to be recovered.

[0095] In this embodiment, the floor panel 14a and the head cover main body 32 are close to each other. Therefore, the height of the head cover main body 32 is minimized, and the volume of the baffle chamber 70 is appropriately suppressed. The first chamber 72, the second chamber 74, and the third chamber 76 allow as much oil contained in the blow-by gas as possible to be collected. For example, the head cover main body 32 of the head cover 30 according to this embodiment has substantially the same front-to-rear and left-to-right dimensions as the head cover main body of a conventional head cover. However, the height of the head cover main body 32 of the head cover 30 according to this embodiment is reduced by 53 mm compared to the head cover main body of a conventional head cover (not shown). Therefore, in the vehicle 10 according to this embodiment, the floor panel 14a of the vehicle 10 can be positioned relatively low, thereby increasing the volume of the cab 14. Furthermore, the volume of the baffle chamber 70 of the head cover main body 32 of the head cover 30 according to this embodiment is reduced by approximately 40% compared to the volume of the baffle chamber of the head cover main body of a conventional head cover. However, experimental results have shown that the head cover 30 including the oil separator 34 having the baffle chamber 70 according to this embodiment can recover oil at a rate equal to or greater than that of conventional head cover 30.

[0096] Therefore, according to this embodiment, it is possible to provide a head cover 30 that can recover as much oil as possible contained in blow-by gas, an internal combustion engine 12 that has such a head cover 30, and a vehicle 10 that has such an internal combustion engine 12.

[0097] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0098] 10...vehicle, 12...internal combustion engine, 14...cab, 22...internal combustion engine body, 30...head cover, 32...head cover body, 33...inner wall portion, 33a...ceiling portion, 33b...peripheral wall portion, 33b1..., 33c...rib, 33d...seal portion, 33e...bolt hole, 34...oil separator, 36...outlet pipe, 38...blow-by gas pipe, 40...oil discharge portion, 42...bottom wall portion, 46...oil recovery wall, 52...flat portion, 54...oil recovery portion, 54a...first surface, 54b...second surface, 56...blow Bigas inlet, 56a...guide wall, 62, 64...side wall, 64a, 64b, 64c, 64d...protrusion, 66...front wall, 68...rear wall, 70...baffle chamber, 72...first chamber, 74...second chamber, 74a...2-1 chamber, 74b...2-2 chamber, 76...third chamber, 82...first wall, 84a...2-1 wall, 84b...2-2 wall, 84c...2-3 wall, 85a...extension, 85b...curved portion, 85c...flat portion, 85d, 85e...opening, 86...wall portion, 88...curved wall.

Claims

1. A head cover for an internal combustion engine, a head cover body having a ceiling portion; and a plate provided opposite to the ceiling portion, the baffle chamber being defined between the ceiling portion and the plate; a blow-by gas inlet provided in the plate for allowing blow-by gas containing oil mist to flow into the baffle chamber; Equipped with The baffle chamber is a first chamber for retaining and separating a portion of the oil mist from the blow-by gas flowing in through the blow-by gas inlet; a second chamber that is in communication with the downstream side of the first chamber along the flow direction of the blow-by gas and has a wall that guides the blow-by gas that has passed through an outlet of the first chamber in a turning-back manner, and separates the oil mist from the blow-by gas; a third chamber that is in communication with the downstream side of the second chamber along the flow direction of the blow-by gas and has a curved wall that guides the blow-by gas that has passed through the second chamber so as to swirl, and that separates the oil mist from the blow-by gas; a throttle portion in the second chamber that reduces an opening area toward an outlet to the third chamber; a blow-by gas outlet communicating with a downstream side of the third chamber along a flow direction of the blow-by gas and discharging the blow-by gas; A head cover having:

2. the first chamber includes a first wall portion that separates the first chamber from the second chamber and has an opening portion that serves both as an exit for the first chamber and an entrance for the second chamber; the first chamber is provided at a position where the blow-by gas directly flows in from the blow-by gas inlet; The head cover according to claim 1.

3. the second chamber is adjacent to the first chamber on a downstream side along a flow direction of the blow-by gas, a second wall portion having a curved surface portion that bends the blow-by gas that has passed through the inlet of the second chamber toward the first chamber, and an oil mist trapping portion that is continuous with the curved surface portion and is provided on the first chamber side; The head cover according to claim 2.

4. the second wall portion of the second chamber is formed to guide the blow-by gas along the wall at an angle of 180° horizontally to the outlet of the first chamber. The head cover according to claim 3.

5. the second chamber includes a third wall portion that defines an outlet of the second chamber along a flow direction of the blow-by gas, the third wall portion is formed so as to reduce the opening of the passage through which the blow-by gas flows toward the outlet of the second chamber. The head cover according to claim 3.

6. The curved wall of the third chamber is formed to swirl the blow-by gas passing through the inlet of the third chamber in a horizontal direction. The head cover according to claim 1.

7. The curved wall of the third chamber guides the blow-by gas to swirl horizontally at an angle between 180° and 270° relative to the outlet of the throttle section. The head cover according to claim 6.

8. The head cover according to any one of claims 1 to 7, an internal combustion engine body on which the head cover is provided; An internal combustion engine having

9. an internal combustion engine according to claim 8; a cab having a floor panel provided above the internal combustion engine; A vehicle having:

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