JP6291240B2 - Internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine including a blow-by gas recirculation passage for ventilating blow-by gas accumulated in a crank chamber.

  Generally, a crank chamber of an internal combustion engine is isolated from a combustion chamber by a cylinder and a piston. However, this isolation is not perfect, and unburned gas leaks in the compression stroke of the internal combustion engine, and combustion gas leaks into the crank chamber through the gap between the cylinder and the piston in the expansion stroke. The leaked blow-by gas causes deterioration of the lubricating oil stored in the crank chamber and corrosion of the internal combustion engine body.

  For this reason, it has been common practice to implement a device for ventilating blow-by gas accumulated in the crank chamber. A general blow-by gas recirculation device (see, for example, Patent Document 1 below) includes a PCV passage that connects a crank chamber and an intake passage (in particular, a surge tank), and a PCV valve that opens and closes the PCV passage. Yes. The blow-by gas in the crank chamber is sent toward the intake passage via the PCV passage, is filled into the cylinder together with the intake air, and is finally recombusted in the combustion chamber. The PCV valve prevents backflow of blow-by gas and intake air from the intake passage toward the crank chamber.

  By the way, in the blow-by gas recirculation device, the inlet of the PCV passage is often arranged on the tangent line of the rotation locus of the crankshaft (particularly, the crank arm and the counterweight). For this reason, for example, the lubricating oil injected toward the piston from the oil jet nozzle for cooling the piston may be struck up by the crankshaft, and the lubricating oil entraining bubbles may enter the PCV passage from the crank chamber. . The lubricating oil that has entered the PCV passage may be transferred to the intake passage side together with the blow-by gas, causing a problem that the lubricating oil stored in the oil pan is taken away to the intake passage.

  In particular, if the amount of the lubricating oil entering the PCV passage becomes excessive, the PCV passage is blocked, and there is a concern that ventilation, which is the original function, cannot be sufficiently performed.

  In order to solve such a problem, it is also considered that a barrier plate is fixed to the inner wall of the oil pan so as to prevent intrusion of the rolled up lubricating oil (for example, see Patent Document 2 below). However, there is a possibility that the lubricating oil may enter the PCV passage from the gap formed between the inlet of the PCV passage and the dam plate, and the removal of the lubricating oil stored in the oil pan is sufficiently suppressed. I can't say.

Japanese Utility Model Publication No. 60-40812 Japanese Utility Model Publication No. 4-54915

  An object of the present invention is to further reduce the removal of lubricating oil stored in an oil pan to an intake passage.

In the present invention, a wall main body that is provided at a position below the inlet of the return passage of the blowby gas that communicates the inner chamber in which the blowby gas accumulates with the intake passage, and that suppresses the penetration of lubricating oil into the return passage side, and the wall A prevention wall comprising a standing wall portion provided at a peripheral edge of the main body and extending upward, and a notch portion provided by cutting out a proximal end side of the standing wall portion fixed to the inner chamber and through which blow-by gas can flow. Equipped with. Here, the inner chamber is a concept including a crank chamber in which blow-by gas is generated, a cam chamber communicating with the crank chamber, and the like. In such a case, the lubricating oil wound up from the crank chamber hits the wall body and the standing wall portion and returns to the oil pan storage portion of the oil pan, and the liquefied lubricating oil entering the reflux passage is cut off. It flows down to the storage part of the oil pan through the notch. Therefore, it is possible to further reduce the carry-off of the lubricating oil to the intake passage. In addition, it is preferable that the wall body has a tip inclined portion extending toward the center of the crankshaft. The tip inclined portion is preferably inclined so as to gradually move upward as it approaches the tip.

Moreover, it is also preferable that the said notch part is formed between the side wall of the said inner chamber, and the base end of the said standing wall part. The side area of the one standing wall portion along the extending direction of the crankshaft in the standing wall portion can be set smaller than the side area of the other standing wall portion . In particular, in the case where the one-side standing wall portion is disposed on the second, third, and fourth cylinder sides, and the other-side standing wall portion is disposed on the first cylinder side, it is preferable to configure such a configuration. . The prevention wall preferably has a cantilever structure whose base end is attached to the side wall of the inner chamber.

  According to the present invention, the removal of lubricating oil stored in the oil pan to the intake passage is further reduced.

The end view which shows the cylinder block and oil pan concerning one Embodiment of this invention. The perspective view which shows a part of oil pan of the same embodiment, and a prevention wall. The top view which shows the prevention wall of the embodiment. Sectional drawing which shows the entrance vicinity of the recirculation | reflux passage of the blowby gas of the embodiment. Sectional drawing which shows the entrance vicinity of the recirculation | reflux channel | path of the blowby gas concerning the modification of this invention.

  An embodiment of the present invention will be described with reference to FIGS.

  The blow-by gas recirculation device 6 attached to the vehicle internal combustion engine in the present embodiment is for sending blow-by gas generated in the inner chamber (crank chamber 7, cam chamber) of the internal combustion engine to the intake passage. The blow-by gas discharge PCV passage 61 corresponding to the blow-by gas recirculation passage, a PCV valve (not shown), and a fresh air introduction passage 62 are used as elements.

  One end of the PCV passage 61 is connected to the crank chamber 7, and the other end communicates with the downstream side of the throttle valve in the intake passage (especially a surge tank), and the crank chamber 7 communicates with the intake passage. Blow-by gas in the crank chamber 7 is discharged to the intake passage via the PCV passage 61.

  More specifically, the PCV passage 61 includes a lower passage 611 having a lower end communicating with the crank chamber 7 in which blow-by gas accumulates, and a space portion 612 that is connected to the upper end of the lower passage 611 and wider than the upper end of the lower passage 611. And an upper passage 613 having a lower end connected to the space 612 and an upper end communicating with the intake passage. The lower passage 611 is formed at a position shifted from the upper passage 613. The upper and lower passages 611 and 613 and the space portion 612 are formed in a cylinder block 60 made of aluminum die casting. In the present embodiment, the PCV passage 61 is formed between the first cylinder and the second cylinder.

  Further, the opening on the crank chamber 7 side of the PCV passage 61 of the present embodiment (the inlet 614 of the PCV passage 61) is set at substantially the same height as the crankshaft. More specifically, the inlet 614 of the PCV passage 61 is disposed slightly below the axis A of the crankshaft.

  The PCV valve increases or decreases the flow rate of blow-by gas flowing through the PCV passage 61. In the present embodiment, the PCV valve is installed on the upper end side of the PCV passage 61. In this embodiment, the PCV valve is a mode in which the valve body that is elastically biased and pressed against the valve seat is displaced in a direction away from the valve seat by the pressure of blow-by gas (against the elastic biasing force). This is a mechanical (differential pressure actuated) valve.

  The PCV valve is closed in a region where the pressure in the intake passage is equal to or higher than the atmospheric pressure (the intake pressure is a positive pressure), and prevents the reverse flow of blow-by gas or intake air through the PCV passage 61. In the region where the pressure in the intake passage is smaller than the atmospheric pressure (the intake pressure is negative) and the pressure difference between the pressure in the crank chamber 7 and the pressure in the intake passage is below a predetermined value, the PCV increases as the pressure difference increases. The valve opening increases, and the flow rate of blow-by gas flowing from the crank chamber 7 toward the intake passage increases.

  However, in a region where the pressure in the intake passage is very small (the intake negative pressure is very large) and the differential pressure between the pressure in the crank chamber 7 and the pressure in the intake passage is greater than or equal to a predetermined value, The opening degree of the PCV valve is reduced, and the flow rate of blow-by gas flowing from the crank chamber 7 toward the intake passage is reduced. When the pressure in the intake passage is minimal (the intake negative pressure is maximized), such as during idle operation or low load operation close to idle operation, the change in the flow rate of the PCV valve with respect to the change in intake passage pressure becomes poor.

  An oil separator (not shown) is interposed between the crank chamber 7 and the PCV valve. The oil separator has a labyrinth structure and performs a gas-liquid separation action for separating the lubricating oil contained in the flowing gas from the gas, and prevents the lubricating oil from being lost from the crank chamber 7.

  The fresh air introduction passage 62 has one end connected to the crank chamber 7 of the internal combustion engine and the other end connected to the upstream side of the throttle valve in the intake passage, and allows the crank chamber 7 to communicate with the intake passage. The fresh air on the intake passage is introduced into the crank chamber 7 via the fresh air introduction passage 62.

  More specifically, the fresh air introduction passage 62 is connected to the lower passage 621 whose lower end communicates with the crank chamber 7 where blow-by gas accumulates, and to the upper end of the lower passage 621 and is wider than the upper end of the lower passage 621. And an upper passage 623 having a lower end connected to the space 622 and an upper end communicating with the intake passage. The lower passage 621 is formed at a position shifted from the upper passage 623. The upper and lower passages 621 and 623 and the space 622 are formed in the cylinder block 60 made of aluminum die casting. The fresh air introduction passage 62 is formed on the opposite side of the PCV passage 61 with the crankshaft interposed therebetween.

  When the PCV valve is open, blow-by gas in the crank chamber 7 is sent to the intake passage via the PCV passage 61 and the PCV valve. At the same time, fresh air flows into the crank chamber 7 from the intake passage via the fresh air introduction passage 62, and the crank chamber 7 is ventilated. The blow-by gas returned to the surge tank in the intake passage is filled in the cylinder and recombusted.

  Thus, in the internal combustion engine of the present embodiment, the oil pan 70 is attached to the lower side of the cylinder block 60 in which the PCV passage 61 and the fresh air introduction passage 62 are formed. The oil pan 70 forms the crank chamber 7 therein, and stores lubricating oil in the lower part. A prevention wall 9 is attached to the side wall 71 of the oil pan 70 in order to suppress the intrusion of lubricating oil that scatters as the crankshaft rotates. FIG. 1 is an end view of the cylinder block 60 and the oil pan 70, and a part of the attachment portion 72 to which the prevention wall 9 is attached is omitted. 4 shows a cross-sectional view of the prevention wall 9 shown in FIG. 3 cut along the line XX.

  The prevention wall 9 is provided at a portion below the inlet 614 of the PCV passage 61 that communicates the crank chamber 7 in which blow-by gas accumulates with the intake passage, and a wall body 91 that suppresses intrusion of lubricating oil into the PCV passage 61 side. A standing wall portion 92 provided on the periphery of the wall body 91 and extending upward; and a notch in which a base end side of the standing wall portion 92 fixed to the crank chamber 7 is cut out and through which blow-by gas can flow. Part 93. The wall body 91 and the standing wall portion 92 are integrally formed.

  The wall main body 91 has a plate shape bent at a midway portion. The base end 911 side is vertically attached to the side wall 71 of the oil pan 70, and the tip end of the base end horizontal portion 912. It has a cantilever structure including a tip inclined portion 914 that is continuous to the side and extends toward the center A direction of the crankshaft, and the tip 913 side extends. The wall body 91 has a symmetrical shape in the left-right direction perpendicular to the extending direction, with the extending end 913 being a free end as a center. The wall main body 91 may have any shape as long as it has a function of shielding the inlet 614 of the PCV passage 61, and is not limited to the symmetrical shape illustrated. The wall main body 91 is set to a size such that the entire inlet 614 of the PCV passage 61 overlaps in a plan view in a state where the prevention wall 9 is assembled to the oil pan 70. In other words, the extending end 913 of the prevention wall 9 extends to the crankshaft side from the inlet 614 of the PCV passage 61 (periphery near the crankshaft).

  The base horizontal portion 912 has a substantially square shape in plan view with the central portion of the base end 911 cut out, and the prevention wall 9 is provided on the oil pan 70 using a bolt indicated by a two-dot chain line. A bolt insertion hole 915 for mounting to the mounting portion 72 is provided. The tip inclined portion 914 has a substantially triangular shape in a plan view with a tapered shape, and is perpendicular to or close to the tangent to the circle formed by the rotation locus of the crankshaft indicated by a two-dot chain line arrow. Inclined to be in a state.

  The standing wall portion 92 includes a standing wall portion 921 on one side and a standing wall portion 922 on the other side with an extending end 913 positioned closest to the crankshaft. A side area of the standing wall portion 921 on the one side is set smaller than a side area of the standing wall portion 922 on the other side. More specifically, the length in the depth direction of the standing wall portion 921 on one side of this embodiment (the length from the end portion on the side wall 71 side of the oil pan 70 to the extending end 913) is the standing wall portion 922 on the other side. Is the same as the length in the depth direction. The height of the standing wall portion 921 on one side (the length extending toward the inlet 614 side of the PCV passage 61) is set lower than the height of the standing wall portion 922 on the other side. In the present embodiment, the standing wall portion 921 on one side is disposed on the second, third, and fourth cylinder sides, and the standing wall portion 922 on the other side is disposed on the first cylinder side. In other words, the prevention wall 9 is arranged at a position deviated from the central portion in the longitudinal direction of the crank chamber 7 along the axial direction of the crankshaft, and along the axial direction of the prevention wall 9 and the crankshaft. The distance between one end is set to be longer than the distance between the prevention wall 9 and the other end along the axial direction of the crankshaft.

  The notch 93 discharges blow-by gas in the crank chamber 7 to the PCV passage 61 side through the space 94 surrounded by the wall body 91 and the standing wall portion 92 of the prevention wall 9 and falls from the PCV passage 61. The droplet-like lubricating oil is transmitted along the side wall 71 of the oil pan 70 and returned to the lower side of the oil pan 70. Specifically, the notch 93 includes a notch 931 on one side where the base end side of the upright wall portion 921 is cut out, and a notch on the other side where the base end side of the upright wall portion 922 is notched. 932. In this embodiment, the distance between the notch 931 on one side (the distance from the side wall 71 of the oil pan 70 to the end on the base end side of the standing wall portion 921) is the distance between the notch 932 on the other side (oil pan). The distance from the side wall 71 of the 70 to the end of the upright wall portion 922 on the proximal end side).

  Thus, in the present embodiment, the ratio of the opening area on one side to the opening area on the other side is about the ratio of the space surrounded by the prevention wall 9, the side wall 71 of the oil pan 70, and the lower surface of the cylinder block 60. The size of the upright wall portion 92 and the cutout portion 93 and the mounting height of the prevention wall 9 are set so as to be 2: 1.

  Next, the flow of blow-by gas passing through the prevention wall 9 of this embodiment will be described.

  First, blow-by gas blown through from the cylinder side to the crank chamber 7 side passes through a gap 95 formed between the upper end of the notch portion 93 and the standing wall portion 92 and the lower surface of the cylinder block 60 from the crank chamber 7, and then reaches the PCV. Enter the passage 61.

  On the other hand, the droplet-like lubricating oil scattered by the rotation of the crankshaft hits the wall body 91 and the standing wall portion 92 of the prevention wall 9 and then falls to the oil pan 70 side by gravity. In addition, as for the mist-like lubricating oil (oil mist) contained in the blow-by gas, part of the oil mist is separated and changed into droplets by contacting the wall main body 91 and the standing wall portion 92 of the prevention wall 9. Lubricating oil is dripped to the oil pan 70 side by gravity.

  In this way, the blow-by gas from which most of the lubricating oil, such as oil mist contained in the gas or droplets, flows in the PCV passage 61.

  The liquid lubricating oil separated from the gas by contact with the wall surface of the passage in the PCV passage 61 falls to the inlet 614 side of the PCV passage 61 due to gravity and is temporarily received on the upper surface side of the prevention wall 9. The lubricating oil that has flowed from the tip inclined portion 914 to the base end 911 side of the prevention wall 9 flows from the notches 931 and 932 through the side wall 71 of the oil pan 70 to the lower storage portion. Therefore, it is possible to reduce the occurrence of a problem that the lubricating oil that has become droplets falls directly from the inlet 614 onto the liquid level of the lubricating oil stored in the oil pan 70 or the crankshaft and entrains bubbles in the lubricating oil. Can be made.

  In the present embodiment, a wall body 91 provided at a portion below the inlet 614 of the PCV passage 61 that communicates the crank chamber 7 where blow-by gas accumulates and the intake passage, and suppresses intrusion of lubricating oil to the PCV passage 61 side; An upright wall portion 92 provided on the peripheral edge of the wall body 91 and extending upward, and a notch portion provided by cutting out a proximal end side of the upright wall portion 92 fixed to the crank chamber 7 and through which blow-by gas can flow. The internal combustion engine provided with the prevention wall 9 comprising 93.

  If it is such, the penetration | invasion in the PCV channel | path 61 of the lubricating oil scraped up by a crankshaft can be suppressed. More specifically, the droplet-like or foam-like lubricating oil splashed by the centrifugal force generated by the rotation of the crankshaft (particularly the crank arm or counterweight) hits the wall main body 91 and the standing wall portion 92 to the oil pan 70 side. It is possible to prevent the lubricant from falling and being taken away to the inlet 614 side of the PCV passage 61 and thus to the intake passage side. That is, even if the lubricating oil hitting the prevention wall 9 climbs over the wall main body 91, the presence of the standing wall portion 92 can suppress the intrusion of the lubricating oil into the inlet 614 of the PCV passage 61. Compared with conventional ones, the amount of lubricant oil taken away can be reduced. Furthermore, it is possible to prevent the lubricating oil from entering the inlet 614 of the PCV passage 61 and prevent the PCV passage 61 from being blocked.

  In addition, on the base end side of the prevention wall 9, specifically, a notch portion 93 through which blow-by gas can flow is formed between the side wall 71 of the oil pan 70 and the base end of the standing wall portion 92. Therefore, the lubricating oil dripped from the PCV passage 61 can be collected by the prevention wall 9 and returned to the lubricating oil reservoir along the side wall 71 of the oil pan 70 through the gap (notch portion 93) on the base end side. . Thereby, foaming of lubricating oil can be reduced.

  In particular, the side area of the standing wall portion 921 on the one side along the extending direction of the crankshaft in the standing wall portion 92 is set smaller than the side area of the standing wall portion 922 on the other side. Therefore, by setting the size of the side area according to the position where the opening of the passage 62 for introducing fresh air (fresh air intake port of the crank chamber 7) is provided and the direction in which the blow-by gas flows in the oil pan 70 is set. The blow-by gas can be discharged efficiently. In the present embodiment, blow-by gas can be sucked more strongly from the side of the standing wall portion 921 on the one side than the standing wall portion 922 on the other side, and the entire crank chamber 7 can be ventilated evenly. In particular, in the present embodiment, the ratio of the opening area on one side to the opening area on the other side is set to about 2: 1 in consideration of the cylinder balance of the internal combustion engine. The ventilation effect is also improved.

  In the present embodiment, since the prevention wall 9 is formed separately from the oil pan 70 and assembled to the oil pan 70, the PCV passage 61 and the fresh air introduction passage 62 are arranged at the arrangement location. Accordingly, the installation location and number of the prevention walls 9 can be set relatively freely.

  In particular, since the wall is formed so that the prevention wall 9 is orthogonal to the tangent to the rotation locus of the crankshaft, the penetration of the lubricating oil into the PCV passage 61 can be effectively suppressed.

  The present invention is not limited to the embodiment described in detail above.

  For example, the standing wall portion 92 of the prevention wall 9 may be anything as long as the side area of the standing wall portion 921 on one side is set smaller than the side area of the standing wall portion 922 on the other side. In addition, the side area is not limited by changing the heights of the standing wall portions 921 and 922 as described above. For example, the internal combustion engine shown in FIG. 5 is different from the above-described embodiment in the structure of the standing wall 92 and the notch 93. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or respond | corresponds to this, and abbreviate | omits description.

  The standing wall portion 92 includes a standing wall portion 921 on one side and a standing wall portion 922 on the other side with an extending end 913 positioned closest to the crankshaft. The length in the depth direction of the standing wall portion 921 on one side (the length from the end portion on the side wall 71 side of the oil pan 70 to the extending end 913) is set shorter than the length in the depth direction of the standing wall portion 922 on the other side. It is. The height of the standing wall portion 921 on one side (the length extending toward the inlet 614 side of the PCV passage 61) is the same as the height of the standing wall portion 922 on the other side.

  The notch portion 93 includes a notch portion 931 on one side where the base end side of the standing wall portion 921 is cut out, and a notch portion 932 on the other side where the base end side of the standing wall portion 922 is notched. Yes. In this embodiment, the distance between the notch 931 on one side (the distance from the side wall 71 of the oil pan 70 to the end on the base end side of the standing wall portion 921) is the distance between the notch 932 on the other side (oil pan). The distance from the side wall 71 of 70 to the base end side end portion of the upright wall portion 922 is set to be longer.

  Therefore, in this modification, the opening area on one side and the opening area on the other side are about 2: with respect to the space surrounded by the prevention wall 9, the side wall 71 of the oil pan 70, and the lower surface of the cylinder block 60. The size of the upright wall portion 92 and the cutout portion 93 and the mounting height of the prevention wall 9 are set so as to be 1.

  If it is such, the effect which is the same as that of embodiment mentioned above or according to this is acquired. Of course, both the height of the standing wall portions 921 and 922 and the length in the depth direction may be different from each other.

  In the above-described embodiment, a relatively low one-side standing wall portion is formed on the second, third, and fourth cylinder sides, and a relatively high other-side standing wall portion is formed on the first cylinder side. However, the present invention is not limited to this, and various changes can be made according to the position of the opening of the passage for introducing fresh air (fresh air intake port of the crank chamber) and the flow direction of fresh air and blow-by gas in the oil pan It is. For example, even when the inlet of the return passage for blow-by gas is formed between the second cylinder and the third cylinder, the position of the opening of the passage for introducing fresh air and the flow of fresh air or blow-by gas Accordingly, the height and depth direction length of the standing wall portion on one side (first and second cylinders) and the standing wall portion on the other side (third and fourth cylinders) may be made different from each other. . Specifically, if the side area of the standing wall portion on the side where blow-by gas is difficult to vent is set to be smaller than the side area of the standing wall portion on the opposite side, the blow-by gas in the oil pan is preferably ventilated. Can do.

  Furthermore, when the side area is changed by making the height of one standing wall portion different from that of the other standing wall portion, the height is changed at a stretch in the vicinity of the extended end, or gradually (linearly / The height may be changed stepwise.

  In the illustrated example, since the oil pan (integrated with the crankcase) is arranged below the cylinder block, the prevention wall is assembled to the oil pan, but the crankcase arranged below the cylinder block. And an oil pan disposed below the crankcase, the prevention wall may be assembled to the crankcase.

  Furthermore, the prevention wall is not limited to a member formed separately from the oil pan or the like and assembled to the oil pan or the like, and may be formed integrally with the oil pan or the like.

  Other specific configurations of each part can be variously modified without departing from the spirit of the present invention.

  The present invention can be applied to an internal combustion engine mounted on a vehicle or the like.

61 ... Blow-by gas recirculation passage (PCV passage)
614 ... Entrance 91 ... Wall body 913 ... Extension end 92 ... Standing wall part 921 ... Standing wall part on one side 922 ... Standing wall part on the other side 93 ... Notch

Claims (5)

A wall body that is provided at a position below the inlet of the return passage of the blow-by gas that communicates the inner chamber in which the blow-by gas accumulates and the intake passage, and suppresses intrusion of lubricating oil into the return passage side;
A standing wall provided on the periphery of the wall body and extending upward;
A prevention wall comprising a cutout portion provided by cutting out the proximal end side of the standing wall portion and allowing flow of blow-by gas ;
An internal combustion engine in which the wall body has a tip inclined portion extending toward the center of the crankshaft, and the tip inclined portion is inclined so as to gradually go upward as approaching the tip . A wall body that is provided at a position below the inlet of the return passage of the blow-by gas that communicates the inner chamber in which the blow-by gas accumulates and the intake passage, and suppresses intrusion of lubricating oil into the return passage side;
A standing wall provided on the periphery of the wall body and extending upward;
A notch portion provided by notching the base end side of the standing wall portion and allowing flow of blow-by gas;
A prevention wall comprising
An internal combustion engine in which the notch is formed between a side wall of the inner chamber and a proximal end of the standing wall . The internal combustion engine according to claim 1 or 2, wherein a side area of one of the standing wall portions along the extending direction of the crankshaft in the standing wall portion is set smaller than a side area of the other standing wall portion. The internal combustion engine according to claim 3, wherein the one-side standing wall portion is disposed on the second, third, and fourth cylinder sides, and the other-side standing wall portion is disposed on the first cylinder side. 5. The internal combustion engine according to claim 1, wherein the prevention wall has a cantilever structure with a base end attached to a side wall of the inner chamber.

Images