JP4117558B2 - Breather device for internal combustion engine - Google Patents

Description

  The present invention relates to a breather device for an internal combustion engine in which gas-liquid separation of blow-by gas is performed.

  In general, blowby gas leaking into the crankcase from between a piston and a cylinder in a compression process or an expansion process of an internal combustion engine is mixed with mist-like oil to become an oil mist. As described above, the blow-by gas containing the oil component and the gas component is usually subjected to gas-liquid separation, and then the oil component is recovered and the gas component is reduced to the internal combustion engine side. At this time, if gas-liquid separation is insufficient, oil consumption increases, and therefore various gas-liquid separation structures and devices have been proposed as oil separators.

As a typical example of such a gas-liquid separation device, a breather device in which a gas-liquid separation chamber is defined in a cylinder head cover of an internal combustion engine is known. For example, Patent Document 1 discloses a breather device in which a gas-liquid separation chamber is formed by a bottom plate that closes an upper wall and a peripheral wall of a cylinder head cover and a lower end thereof. In this conventional apparatus, when the internal combustion engine is in a normal posture, the bottom plate is inclined, an oil return port is formed at the lowest part of the lower side edge of the bottom plate, and the upper side facing the oil return port A blow-by gas inlet is provided at the side edge portion.
JP 2002-129930 A

  However, since the oil return port is provided in the middle of the blow-by gas passage, that is, on the lower side edge of the bottom plate, the above-mentioned conventional apparatus has blow-by gas whose oil content has not been sufficiently separated, or its oil return. Although the oil component is separated and removed to some extent on the upstream side of the mouth, blow-by gas in which the oil in the vicinity of the oil return port is mixed again may flow out of the oil return port. If this happens, the amount of oil taken away increases, resulting in insufficient gas-liquid separation of the blow-by gas, and the reduction efficiency of the blow-by gas is undesirably lowered.

  In particular, in recent years, the output of engines has been increasing more and more, the pressure in the cylinder tends to be further increased, and the tension of the piston ring tends to be reduced due to the demand for further reduction in fuel consumption. For the reason, the flow rate of blow-by gas tends to increase. Further, engine control devices that are hydraulically driven tend to be added in order to improve the performance of vehicle devices, and the discharge amount of the oil pump and the amount of oil leakage from each hydraulic drive device tend to increase.

  Furthermore, in order to achieve further higher performance, it has been practiced and intended to mount many functional members and devices in the cylinder head cover, and the space for providing the breather device structure tends to be reduced. On the other hand, in the unlikely event of a collision such as a vehicle, the gap between the engine hood and the engine tends to be expanded so that priority is given to pedestrian protection. As a result, the restriction on the overall height of the engine is becoming very large, and the height of the cylinder head cover itself and the components installed thereon tend to be limited. Therefore, reduction of the space for providing the breather device is further desired.

  Therefore, from such a situation, there is a strong desire for a breather apparatus that can sufficiently suppress the removal of oil by blow-by gas even in a narrower space and can further improve gas-liquid separation efficiency.

  Therefore, the present invention has been made in view of such circumstances, and it is possible to prevent blow-by gas containing an oil component from flowing into the oil recovery side, thereby suppressing the removal (carrying out) of the oil component. An object of the present invention is to provide a breather device for an internal combustion engine capable of improving the gas-liquid separation efficiency of blow-by gas.

  In order to solve the above-mentioned problem, a breather device for an internal combustion engine according to the present invention is supplied with blow-by gas containing an oil component and a gas component to perform gas-liquid separation, and a cylinder head cover having an open end, A gas-liquid separation chamber defined by a baffle plate provided so as to close or cover the open end of the cylinder head cover is provided, and the baffle plate is in a normal state (a normal posture of the internal combustion engine). In the installed state, it is installed at an inclination relative to the horizontal, and in the installed state, the blow-by gas formed at the lowest part is introduced and the oil component separated from the blow-by gas is discharged. Has an inlet. In the gas-liquid separation chamber, the flow of blow-by gas extending from the introduction port to a discharge port from which the blow-by gas from which the oil component is separated is provided at a position higher than the introduction port is discharged. A path is formed.

  In the breather device of the internal combustion engine configured as described above, the gas-liquid in which the blow-by gas, which is a gas-liquid mixture containing the oil and gas components, is defined in the cylinder plate from the inlet provided in the baffle plate. Supplied to the separation chamber. The blow-by gas collides with the inner wall of the cylinder head cover and the baffle plate while flowing from the introduction port through the blow-by gas flow path toward the discharge port, whereby gas-liquid separation is performed.

  In the present invention, the inlet is located at the lowest part (the part having the lowest level in the vertical direction) in the normal state of the internal combustion engine and also serves as an oil outlet, and the separated oil component is discharged from the inlet. It is discharged outside the liquid separation chamber. Therefore, inconvenience such as inflow of blow-by gas containing oil to the oil recovery side, which is a concern in the conventional apparatus in which an oil return port different from the introduction port is provided in the middle of the flow path of blow-by gas, is prevented. The

  Further, it has a substantially plate shape and is provided in the gas-liquid separation chamber so as to intersect with the flow direction of the blow-by gas, and a plurality of holes are formed in the whole including at least a part of the edge. It is preferable to provide an auxiliary member. Alternatively, in other words, focusing on the form at the edge of the auxiliary member, it is substantially plate-shaped and is provided in the gas-liquid separation chamber so as to intersect the flow direction of blow-by gas, and a plurality of holes are formed. It is also preferable to provide an auxiliary member having a notch formed in at least a part of the edge.

  In this way, the auxiliary member is provided in a projecting manner in the flow path so as to prevent the flow of blow-by gas, and when the blow-by gas and the auxiliary member are in contact with each other, the oil content contained in the blow-by gas as relatively small droplets is reduced. To be separated. At this time, although a pressure loss occurs while the blow-by gas passes through the auxiliary member, a hole is also formed in the peripheral portion of the auxiliary member, and the blow-by gas can pass through the hole provided in the peripheral portion. The pressure loss is reduced as compared with the case where there is no hole in the peripheral portion.

  According to the breather device of the present invention, it is possible to prevent blow-by gas containing oil from flowing into the oil recovery side, and it is possible to reduce the amount of oil taken away and increase the gas-liquid separation efficiency of blow-by gas. It becomes.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, positional relationships such as up, down, left and right are based on the positional relationships shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a side view schematically showing an example of the configuration of an internal combustion engine including a breather device according to the present invention.

  In the internal combustion engine 100, a cylinder block 30, a cylinder head 40, and a cylinder head cover 50 are placed in this order on a crankcase 20, and an oil pan 10 is provided below the crankcase 20. Further, the internal combustion engine 100 is mounted on a vehicle or the like, and when the vehicle is held horizontally and is in an upright state (a state in which the vehicle is placed in a normal posture), the arrow L with respect to the horizontal It is installed in a state inclined at a certain angle in the direction indicated by.

  Therefore, when the internal combustion engine 100 is held in the upright state, the cylinder head cover 50, the cylinder head 40, the cylinder block 30, and the crankcase 20 are located at the vertical level at the lower end of the cylinder head cover 50, the cylinder head 40, the cylinder block 30, and the crankcase 20 It is considered as the minimum part. On the contrary, the part located closer to the H direction in the figure is the highest part of the vertical level at the lower end thereof.

  In addition, illustration was abbreviate | omitted about the crankshaft provided in the crankcase 20, the auxiliary machines connected via the pulley etc. which interlock | cooperate with the crankshaft, and other auxiliary machines.

  Here, the cylinder head cover 50 has a substantially box shape in which a lower end in FIG. 1, that is, a joint end with the cylinder head 40 is opened. FIG. 2 is a bottom view of the cylinder head cover 50, that is, a schematic view showing a state in which the cylinder head cover 50 is viewed from the joint surface (mating surface) with the cylinder head 40.

  The cylinder head cover 50 is formed with an annular groove 53 at the lower end of the outer peripheral wall 51 into which a sealing material (not shown) for sealing the interface with the cylinder head 40 is fitted. In addition, cylindrical holder holding portions 59 a, 59 b, 59 c on which an unillustrated spark plug holder is fitted are provided in parallel on the upper wall of the cylinder head cover 50 along the longitudinal direction of the outer peripheral wall 51.

  On the inner side of the outer peripheral wall 51, an inner peripheral wall 55 having a substantially rectangular shape formed so as to surround the holder holding portions 59a to 59c protrudes from the upper wall of the cylinder head cover 50 toward the cylinder head 40. Is provided. 2 is parallel to the lower end surface of the outer peripheral wall 51 (that is, the surface of the annular groove 53) and is lower than the lower end surface of the outer peripheral wall 51. Located at a high level.

  Furthermore, the respective lower end surfaces of the outer peripheral wall 51 and the inner peripheral wall 55 are inclined in the direction indicated by the arrow L in the drawing according to the inclination of the internal combustion engine 100 in the normal position. Furthermore, a discharge port 57 through which blow-by gas is discharged is provided at the corner of the inner peripheral wall 55 near the arrow H direction.

  Furthermore, the baffle plate 1 shown in FIGS. 3A to 3C is brought into contact with and joined to the lower end surface of the inner peripheral wall 55. Here, FIGS. 3A to 3C are a plan view, a side view, and a bottom view schematically showing the baffle plate 1 joined to the lower end surface of the inner peripheral wall 55, respectively. That is, FIGS. 3A to 3C show the cylinder head cover 50 from the upper side in the state where the baffle plate 1 is joined to the inner peripheral wall 55 from the upper side (in the direction of the arrow H, that is, the right side in FIG. 1). ) And a view seen through from below.

  The baffle plate 1 is mainly composed of a bottom plate 2 having a substantially rectangular shape as a whole. The bottom plate 2 is joined to the peripheral edge of the closed portion 2a formed so as to close the open portion at the lower end of the inner peripheral wall of the cylinder head cover 50 and a lower end surface of the cylinder head cover 50 (surface indicated by a dotted pattern in FIG. 2). 2b is formed.

  Further, in the bottom plate 2, through holes 8a, 8b, 8c into which the spark plug holders are fitted are formed at positions corresponding to the holder holding portions 59a, 59b, 59c of the cylinder head cover 50, and their peripheral edges are also joined. It is included in part 2b.

  Further, blow-by gas inlets 3 are provided at the corners closest to the arrow L direction in the closed portion 2a. Therefore, the inlet 3 is formed at the lowest part of the baffle plate 1, that is, at the lowest position on the vertical level when the internal combustion engine 100 is in the normal state shown in FIG. Furthermore, a cover plate 4 is installed with a certain gap so as to cover the inlet 3 from above.

  Further, in the baffle plate 1, an auxiliary separating portion 6 composed of perforated plate units 61 and 62 protrudes on the closing portion 2 a at a position facing the introduction port 3 across the through holes 8 a and 8 b. 4A to 4C are a left side view, a front view, and a right side view of the perforated plate unit 61, respectively. The perforated plate unit 61 is a unit in which perforated plates 7a and 7c (auxiliary members) are coupled via a bottom plate 7b. In the present embodiment, each of the perforated plates 7a and 7c is a substantially triangular flat plate, and has a plurality of holes P1 and P2 formed at regular intervals. As such porous plates 7a and 7c, for example, metal plates (so-called punching plates) in which a plurality of holes are punched can be employed.

  Further, the plurality of holes P1,... Are all circular with a desired diameter according to the oil droplets to be separated. On the other hand, a plurality of holes P2,... Provided at the edge portions of the perforated plates 7a, 7c are substantially semicircular or partially circular cutouts.

  When the baffle plate 1 is in contact with and joined to the lower end surface of the cylinder head cover 50, the gas-liquid separation chamber 9 defined by the inner peripheral wall 55 and the baffle plate 1 is formed in the upper space inside the cylinder head cover 50. It is formed. A valve operating mechanism (not shown) including a camshaft and the like is accommodated in the space below the baffle plate 1 in the cylinder head cover 50.

  The gas-liquid separation chamber 9 is a PCV (Positive Crankcase Ventilation) in which the oil component is separated and removed while the blow-by gas that is a gas-liquid mixture of oil droplets (oil component) and combustion gas (gas component) flows. Functions as an oil separation passage. The gas-liquid separation chamber 9 includes a front stage portion 9a located near the introduction port 3, a rear stage portion 9c located near the discharge port 57, and a middle stage portion 9b located between the front stage portion 9a and the rear stage portion 9c. It is formed in a substantially U-shaped cross section that is folded back at the middle step 9b. Further, the middle stage portion 9b is a constricted portion or a narrowed portion having a smaller space cross-sectional area than the front stage portion 9a and the rear stage portion 9c.

  In the breather device configured as described above, when blow-by gas B containing oil is supplied from the inlet 3 into the gas-liquid separation chamber 9, first, the lid plate 4 disposed immediately above the inlet 3 is applied to the lid plate 4. Either it collides directly or the flow is disturbed by the cover plate 4 and collides with surrounding wall surfaces such as the inner peripheral wall 55. Oil droplets contained in the blow-by gas B having a relatively large diameter are likely to lose momentum there and are separated from the blow-by gas B. The oil droplets flow down along the wall and are discharged to the outside from the inlet 3 that also serves as an oil outlet.

  Thereafter, the blow-by gas B proceeds in the order of the front stage part 9a, the middle stage part 9b, and the rear stage part 9c, and flows in the gas-liquid separation chamber 9 toward the discharge port 57. At that time, the direction of the blow-by gas B that has passed through the front-stage portion 9a is changed in the middle-stage portion 9b that corresponds to the folded portion of the substantially U-shaped flow path. Moreover, since the cross-sectional area of the middle stage part 9b is made smaller than the front stage part 9a, the blow-by gas B is accelerated.

  The accelerated blow-by gas B flows into the rear stage portion 9c and collides with the porous plates 7a and 7c when sequentially passing through the porous plate units 62 and 61 constituting the auxiliary separation unit 6. The perforated plates 7a and 7c are provided so as to extend in a direction perpendicular to the flow of the blow-by gas B, that is, so as to intersect with the flow direction of the blow-by gas B. Small oil droplets hit the walls and lose momentum and are separated from blow-by gas B. The oil droplets flow down through the perforated plates 7a and 7c.

  The oil collected on the baffle plate 1 flows down the upper surface of the blocking portion 2a toward the middle step portion 9b and the front step portion 9a due to the inclination of the baffle plate 1, and is discharged from the introduction port 3 to the outside. On the other hand, the blow-by gas B from which the oil component has been separated and removed is discharged from the discharge port 57 and returned to the intake system of the internal combustion engine 100.

  According to such a breather device, the introduction port 3 is positioned at the lowest position in the state in which the internal combustion engine 100 is placed and also serves as an oil discharge port, so that the blow-by gas B containing oil flows out to the oil recovery side. Can be prevented. Therefore, it is possible to suppress oil removal (take-out) which is a concern in the conventional apparatus, and it is possible to suppress a reduction in the gas-liquid separation efficiency of the blow-by gas B and thus the reduction efficiency of the blow-by gas B.

  Further, since the cover plate 4 is provided so as to cover it directly above the inlet 3, most oil droplets can be separated and removed from the blow-by gas B immediately after being introduced into the gas-liquid separation chamber 9. Further, the perforated plates 7a and 7c constituting the auxiliary separation unit 6 are provided in the gas-liquid separation chamber 9 so as to prevent the flow of the blow-by gas B, thereby separating oil droplets having a relatively small diameter. Therefore, the gas-liquid separation performance can be further improved.

  Furthermore, since the hole P1 is provided on the entire surface of the perforated plates 7a and 7c, and the notch-like hole P2 is further provided in the peripheral part, the blow-by gas B is provided in the peripheral part. By passing through the pressure loss, the pressure loss can be reduced as compared with the case where there is no such hole P2 in the peripheral portion. Therefore, even when the auxiliary separation portion 6 is installed in a place where the space cross-sectional area of the passage is narrow, a desired small hole diameter can be sufficiently ensured.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible in the limit which does not change the summary. For example, although it is preferable to provide the cover plate 4 and the auxiliary separation unit 6, these may be omitted. Moreover, the shape of each structural member is not restricted to illustration, For example, the perforated plates 7a and 7c may be curved plates, and may be rectangular.

  The breather device for an internal combustion engine according to the present invention can improve the gas-liquid separation performance of blow-by gas by suppressing the removal of oil, so that higher output and higher performance can be achieved and further safety can be achieved. The present invention can be widely used for internal combustion engines in which the performance is pursued, and devices, motives, facilities and the like equipped with such internal combustion engines.

It is a side view showing typically an example of composition of an internal-combustion engine provided with a breather device by the present invention. FIG. 3 is a bottom view of the cylinder head cover 50 (a schematic view showing a state in which the cylinder head cover 50 is viewed from a joint surface with the cylinder head 40). 3A to 3C are a plan view, a side view, and a bottom view schematically showing the baffle plate 1 joined to the lower end surface of the inner peripheral wall 55, respectively. 4A to 4C are a left side view, a front view, and a right side view of the perforated plate unit 61, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Baffle plate, 2 ... Bottom plate, 2a ... Closure part, 2b ... Joint part, 3 ... Introducing port, 4 ... Cover plate, 6 ... Auxiliary separation part, 7a, 7c ... Perforated plate (auxiliary member), 7b ... Bottom plate, 8a, 8b, 8c ... through-hole, 9 ... gas-liquid separation chamber, 9c ... rear stage, 9a ... front stage, 9b ... middle stage, 10 ... oil pan, 20 ... crankcase, 30 ... cylinder block, 40 ... cylinder head 50 ... cylinder head cover, 51 ... outer peripheral wall, 53 ... annular groove, 55 ... inner peripheral wall, 57 ... discharge port, 59a, 59b, 59c ... holder holding part, 61, 62 ... perforated plate unit, 100 ... internal combustion engine, P1, P2 ... holes.

Claims (7)

A breather device for an internal combustion engine in which blow-by gas containing oil and gas is supplied to perform gas-liquid separation,
A gas-liquid separation chamber defined by a cylinder head cover having an open end and a baffle plate provided so as to close the open end of the cylinder head cover;
The baffle plate is installed in an inclined state with respect to the horizontal in the normal state of the internal combustion engine, and is formed at the lowest part in the installation state, and the blow-by gas is introduced from the blow-by gas. have a inlet separated oil content is discharged,
Furthermore, it has a substantially plate shape and is provided in the gas-liquid separation chamber so as to intersect with the flow direction of the blow-by gas, and a plurality of holes are formed in the whole including at least a part of the edge. Provided auxiliary members,
Furthermore, a notch-shaped hole is formed in at least a part of the edge portion of the auxiliary member excluding the bottom portion.
A breather device for an internal combustion engine. A breather device for an internal combustion engine in which blow-by gas containing oil and gas is supplied to perform gas-liquid separation,
A gas-liquid separation chamber defined by a cylinder head cover having an open end and a baffle plate provided so as to close the open end of the cylinder head cover;
The baffle plate is installed in an inclined state with respect to the horizontal in the normal state of the internal combustion engine, and is formed at the lowest part in the installation state, and the blow-by gas is introduced from the blow-by gas. Having an inlet through which the separated oil is discharged;
Further, the gas-liquid separation chamber is formed in a shape that is folded back at an intermediate folding portion, the introduction port on one side across the folding portion, and an exhaust port from which the blow-by gas from which oil has been separated is discharged on the other side Is provided,
A breather device for an internal combustion engine. The gas-liquid separation chamber is formed so as to be folded at a folding portion in the middle, and the introduction port is provided on one side across the folding portion, and a discharge port for discharging the blow-by gas from which oil has been separated is provided on the other side. The breather device for an internal combustion engine according to claim 1. It has a substantially plate shape, is provided in the gas-liquid separation chamber so as to intersect with the flow direction of the blow-by gas, and a plurality of holes are formed in the whole including at least part of the edge. With auxiliary members,
Furthermore, a notch-shaped hole is formed in at least a part of the edge portion of the auxiliary member excluding the bottom portion.
A breather device for an internal combustion engine according to claim 2. The breather device for an internal combustion engine according to claim 3 or 4, wherein a throttle portion having a reduced spatial cross-sectional area is formed on an upstream side of the folded portion. The breather device for an internal combustion engine according to claim 5, wherein the auxiliary member is provided downstream of the throttle portion. The breather device for an internal combustion engine according to any one of claims 1 to 6, further comprising a cover plate disposed above the introduction port.

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