BLOWBY GAS DUCT

Abstract

Blow-by gas venting device, comprising: a blow-by gas line (23) extending from a height position of an upper end part of an internal combustion engine (1) to a height position of a lower end part of the internal combustion engine (1), wherein the blow-by gas line (23) is exposed to outside air and has an outlet part (33) that is released to an atmosphere; a heating chamber (24) provided in the center of the blow-by gas line (23) and in a flywheel housing (10) of the internal combustion engine (1), the heating chamber (24) being configured to heat blow-by gas; and a drain mechanism (60) provided and configured in the heating chamber (24) to drain oil accumulated in the heating chamber (24), and comprising a drain valve configured to prevent oil from being drained when the drain valve is closed and to allow oil to be drained when the drain valve is open, the drain valve being accessible through a hole (70) provided in the flywheel housing (10).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a blowby gas discharge device, and more particularly to a device for discharging blowby gas into the atmosphere through a blowby gas line exposed to the outside air. BACKGROUND OF THE TECHNOLOGY

[0002] Generally, blowby gas generated in the crankcase of an internal combustion engine is circulated in an air intake system, sent into a combustion chamber, and burned together with an air / fuel mixture in the combustion chamber. SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0003] Meanwhile, a device that discharges blowby gas into the atmosphere instead of circulating it in an air intake system is also known (see, for example, JP H01-95513 U). In this case, it may be considered to provide a blowby gas line exposed to the outside air and extending from a height position of an upper end part of the internal combustion engine to a height position of a lower end part of the internal combustion engine, and discharge the blowby gas into the atmosphere through the blowby gas line.

[0004] In such a case, however, since the blowby gas line is cooled by the outside air, the blowby gas flowing through the pipe is also cooled, resulting in condensed water in the pipe due to the blowby gas. If the outside air temperature is equal to or lower than freezing point, the condensed water may freeze and block the inside of the pipe.

[0005] JP H01-95 513 U describes a blowby gas discharge device comprising a blowby gas line extending from a height position of an upper end portion of an internal combustion engine. It is exposed to outside air and has an outlet portion that is released to the atmosphere. Furthermore, the discharge device comprises a heating chamber provided in a flywheel housing of the internal combustion engine.

[0006] JP S58-156 112 U describes another blowby gas discharge device. Further blowby gas discharge devices are described in JP S62-721 U and JP 2012-172 628 A.

[0007] The present disclosure provides a blowby gas discharge device capable of preventing freezing of condensed water in a blowby gas line. SOLUTION TO THE PROBLEM

[0008] According to one aspect of the present disclosure, a blowby gas discharge device includes: a blowby gas line extending from a height position of an upper end part of an internal combustion engine to a height position of a lower end part of the internal combustion engine, the blowby gas line being exposed to outside air and having an outlet part released to an atmosphere; a heating chamber provided in a center of the blowby gas line and in a flywheel housing of the internal combustion engine, the heating chamber configured to heat blowby gas; and a discharge mechanism provided in the heating chamber and configured to discharge oil accumulated in the heating chamber.

[0009] The drain mechanism includes a drain valve configured to prevent the oil from being drained when the drain valve is closed and to allow the oil to be drained when the drain valve is open.

[0010] The drain valve may be a check valve, and the check valve may include a valve body and a biasing member configured to bias the valve body toward a valve closing side.

[0011] The drain valve can be a drain plug.

[0012] According to the invention, the drain valve is configured to be accessible through a hole provided in the flywheel housing. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0013] According to the present disclosure, it is possible to prevent freezing of condensed water in a blow-by gas line. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional side view illustrating a structure of an end part of an internal combustion engine. Fig. 2 is a schematic cross-sectional rear view illustrating a heating chamber. Fig. 3 is a schematic cross-sectional rear view illustrating a drain mechanism. Fig. 4 is a schematic cross-sectional rear view for explaining a working method for discharging oil. Fig. 5 is a schematic cross-sectional rear view illustrating a discharge mechanism according to a first modification. Fig. 6 is a schematic cross-sectional rear view illustrating a discharge mechanism according to a second modification.

[0014] Parts (A) and (B) of Fig. 7 show a discharge mechanism according to a third modification and part (A) of Fig. 7 is a left side view of a drain plug and part (B) of Fig. Figure 7 is a schematic cross-sectional rear view.

[0015] Parts (A) and (B) of Fig. 8 show a discharge mechanism according to a fourth modification and part (A) of Fig. 8 is a left side view of a drain plug and part (B) of Fig. Figure 8 is a schematic cross-sectional rear view.

[0016] Fig. 9 is a schematic cross-sectional rear view illustrating a discharge mechanism according to a fifth modification. DESCRIPTION OF THE EMBODIMENTS

[0017] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. However, it should be noted that the present disclosure is not limited to the following embodiment.

[0018] Fig. 1 is a cross-sectional side view illustrating a structure of an end part of an internal combustion engine according to the present embodiment. An internal combustion engine (engine) 1 is a diesel engine mounted on a vehicle (not shown in the drawing), and the vehicle is a large vehicle such as a truck. However, the types, uses, and so on of the vehicle and the engine are not particularly limited, and the vehicle may be a small vehicle such as a car, and the engine may be a gasoline engine. The engine is mounted vertically on the vehicle. The front, rear, left, right, upper, and lower sides of the vehicle and the engine are as shown in the drawing.

[0019] The engine 1 includes an integral cylinder block 2, which includes a crankcase (not shown in the drawing), a cylinder head 3 fixed to an upper end portion of the cylinder block 2, a head cover 4 fixed to an upper end portion of the cylinder head 3, and an oil pan 5 fixed to a lower end portion of the crankcase. A crankshaft 6 is rotatably supported by the crankcase, and a camshaft 7 is rotatably supported by the cylinder head 3.

[0020] A flywheel 8 is fixed to a rear end surface portion of the crankshaft 6 by a plurality of bolts 9. A flywheel housing 10, which houses the flywheel 8, is fixed to the cylinder block 2 by bolts or the like (not shown in the drawing). However, the flywheel housing 10 may be integrally formed in the cylinder block 2. A cylindrical flywheel chamber 11 is provided in the flywheel housing 10, which houses the flywheel 8 so that the flywheel is substantially rotatable. A clutch device (not shown in the drawing) is connected to a rear end portion of the flywheel housing 10, and a clutch input shaft of the clutch device is coaxially connected to the crankshaft 6. A part of the oil pan 5 is fixed to the flywheel housing 10 by a bolt 12.

[0021] A mechanism chamber is provided between a rear end surface portion of the cylinder block 2 and the flywheel housing 10. A power transmission mechanism that transmits power from the crankshaft 6 to the camshaft 7 is housed within the mechanism chamber. In the present embodiment, the power transmission mechanism includes a gear mechanism 13 comprising a plurality of meshing gears, and the mechanism chamber includes a gear chamber 14. However, the type of power transmission mechanism is arbitrary, and the power transmission mechanism may include, for example, a chain mechanism. The gear mechanism 13 includes a crank gear 15 fixed to the crankshaft 6, a cam gear 16 fixed to the camshaft 7, and a plurality (in the present embodiment, two) intermediate gears 17A and 17B arranged between the crank gear 15 and the cam gear 16.The transmission chamber 14 communicates with a crank chamber 18 in the crankcase, a valve chamber 3A of the cylinder head 3 and a cover chamber 19 of the head cover 4.

[0022] C1 and C2 each represent a center axis of the crankshaft 6 and a center axis of the camshaft 7.

[0023] A rear end part of the cylinder head 3 is integrally provided with a transmission chamber partition wall 20 having a semi-rectangular frame shape (a shape like a letter U) as viewed in a plan view and protruding from the rear end part of the cylinder head 3. An interior space of the transmission chamber partition wall 20 is a part of the transmission chamber 14. An upper end surface of the flywheel housing 10 is brought into close contact with a lower end surface of the transmission chamber partition wall 20, and a lower end surface of the head cover 4 is brought into close contact with an upper end surface of the transmission chamber partition wall 20.

[0024] A rear end portion of the crankshaft 6 protrudes into the rearwardly located flywheel chamber 11 through an insertion hole 21 of the flywheel housing 10. A sealing member (not shown in the drawing) is provided at a peripheral portion of the insertion hole 21 to prevent oil and gas from leaking from the transmission chamber 14.

[0025] As is known, blowby gas leaks from a combustion chamber of a cylinder into the crank chamber 18 through a gap between a piston ring and a cylinder bore. The blowby gas is introduced into the cover chamber 19 through the gear chamber 14 and another gas passage hole.

[0026] An oil separator 22 is provided in the cover chamber 19 to separate oil from the blowby gas. Although not shown in the drawing, the oil separator 22 has a meandering passage that allows the blowby gas to flow therethrough. In the present embodiment, the blowby gas, from which oil has been separated by the oil separator 22, is discharged to the atmosphere through a gas line 23 serving as a blowby gas line.

[0027] The gas pipe 23 is exposed to the outside air and is directly cooled by the outside air. In particular, the gas pipe 23 of the present disclosure is formed of a metal such as stainless steel, and the entire gas pipe 23 is exposed to the outside air, so it is easily cooled by the outside air. As a result, blowby gas passing through the gas pipe 23 is also cooled, and condensed water due to the blowby gas is cooled in the gas pipe 23. Therefore, for example, in a cold area or the like, when the outside air temperature is equal to or lower than freezing point, the condensed water may freeze and block the inside of the gas pipe 23. If the inside of the gas pipe 23 is blocked, it may interfere with the discharge of blowby gas.

[0028] For this reason, in the present embodiment, a heating chamber 24 that heats blowby gas is provided in the center of the gas passage 23. Blowby gas is heated in the heating chamber 24, thereby preventing the generation of condensed water due to blowby gas and its freezing. Specifically, the heating chamber 24 is provided inside the flywheel housing 10, is adjacent to the gear chamber 14 with a partition (in the present embodiment, a lid 41 to be described below) interposed therebetween, and heats blowby gas by heat received from oil in the gear chamber 14. Therefore, it is possible to efficiently heat blowby gas without providing a dedicated heat source. Here, the configuration of the blowby gas discharge device will be described in detail below.

[0029] The whole of the gas line 23 extends from a height position of an upper end part of the engine 1 to a height position of a lower end part of the engine 1. However, the gas line 23 is divided into two parts at a position in the middle of the height direction, that is, an upstream side gas line 25 and a downstream side gas line 26 (by an imaginary line in Fig. 1). The heating chamber 24 is connected between the upstream gas line 25 and the downstream gas line 26. Both the upstream gas line 25 and the downstream gas line 26 are formed of a metal, such as stainless steel, and are exposed to the outside air outside the engine.

[0030] An inlet portion 27 of the upstream gas line 25 is connected to the oil separator 22. An outlet port 28 is provided in the head cover 4, allowing blow-by gas separated from the oil to flow out of the oil separator 22. The inlet portion 27 of the upstream gas line 25 is connected to the outlet port 28. The inlet portion 27 of the upstream gas line 25 is an inlet portion of the gas line 23. Since the head cover 4 and the oil separator 22 are provided at the height position of the upper end portion of the engine 1, and the inlet portion 27 of the upstream gas line 25 is connected to the oil separator 22, the gas line 23 extends downstream of the height position of the upper end portion of the engine 1.

[0031] The oil separator 22 may not be provided inside the head cover 4, but may be provided outside the head cover 4. The reference symbol "22A" in the drawing represents a partition wall defining the oil separator 22.

[0032] On the other hand, as also in Fig. 2, an outlet portion 29 of the upstream gas line 25 is connected to the heating chamber 24. An introduction port 30 is provided in a right and upper end portion of the heating chamber 24, which introduces blowby gas into the heating chamber 24, and the outlet portion 29 of the upstream gas line 25 is connected to the introduction port 30.

[0033] An inlet portion 31 of the downstream gas line 26 is also connected to the heating chamber 24. A discharge port 32 is provided in a left and upper end portion of the heating chamber 24 to discharge blow-by gas from the heating chamber 24, and the inlet portion 31 of the downstream gas line 26 is connected to the discharge port 32.

[0034] On the other hand, as in Fig. 1, the downstream gas passage 26 passes through the left side of the flywheel housing 10 and extends downward as it goes downstream. Further, an outlet portion 33 of the downstream gas passage 26 is disposed at the height position of the lower end portion of the engine 1 and is released into the atmosphere in a state where the outlet portion 33 faces downward. As a result, it is possible to prevent the engine from being contaminated by blowby gas discharged from the outlet portion 33. The outlet portion 33 of the downstream gas passage 26 is the outlet portion of the gas passage 23. Therefore, the gas passage 23 is extended to the height position of the lower end portion of the engine 1.

[0035] The heating chamber 24 is provided inside the flywheel housing 10 and in an upper end portion of the flywheel housing 10. The heating chamber 24 is mainly defined by a cavity 40 provided in the flywheel housing 10 and opening toward the front side, and the lid 41 closes a front end opening of the cavity 40. The flywheel housing 10 is cast in aluminum or iron, and the lid 41 is formed of any metal plate. However, it is preferable that the material of the lid 41 should be a material having excellent heat resistance and corrosion resistance and relatively high thermal conductivity, such as aluminum or stainless steel. The lid 41 is superimposed on a lid mounting surface 42 of the flywheel housing 10, which is positioned around the front end opening of the cavity 40, and is fixed detachably and airtight by a plurality of screws 43.

[0036] As in Fig. 2, the heating chamber 24 of the present embodiment has a fan shape or a substantial fan shape extending around the central axis C1 of the crankshaft in a rear view as viewed from the rear side (i.e., one end side in the direction of the central axis C1 of the crankshaft). The shape of the cover 41 as viewed in a rear view is the same. The introduction port 30 is provided on the right side of the upper end part of the heating chamber 24, and the discharge port 32 is provided on the left side of the upper end part of the heating chamber 24. The center axes of the introduction port 30 and the discharge port 32 extend substantially along the radial direction of the central axis C1 of the crankshaft.

[0037] Within the heating chamber 24, a partition wall 44 is provided, which forms a meander-shaped passage in the heating chamber 24. The partition wall 44 is provided integrally in the flywheel housing 10. As shown in Fig. 1, the partition wall 44 protrudes integrally and straightly from a rear inner wall surface 45 of the heating chamber 24, which is the bottom of the cavity 40, toward the front side and is in airtight contact with the lid 41, thereby vertically partitioning the space in the heating chamber 24. Furthermore, as shown in Fig. 2, the partition wall 44 is integrally and in an arc shape to the right from the left inner wall surface 46 of the heating chamber 24, which is one side surface of the cavity 40, to a position where a predetermined gap 48 is formed between the partition wall 44 and a right inner wall surface 47 of the heating chamber 24, which is the surface of the other side of the cavity 40.

[0038] An outlet of the introduction port 30 faces the gap 48 and a lower inner wall surface 49 of the heating chamber 24. Therefore, the introduction port 30 is configured to allow blowby gas discharged from the introduction port 30 to flow linearly into a space 50 below the partition wall 44 through the gap 48, as shown by arrows.

[0039] As in Fig. 1, the heating chamber 24 and the flywheel chamber 11 are overlapped in the vertical direction, and a lower end part of the heating chamber 24 is located at a front side of the upper end part of the flywheel chamber 11. In the lower space 50 of the heating chamber 24, a step 51 is provided, which protrudes toward the front side on the rear inner wall surface 45 of the heating chamber 24. By providing the step 51, it is possible to provide the flywheel chamber 11 with a sufficient size on the rear side behind the rear inner wall surface 45 while making room for the flywheel 8.

[0040] The shape of the heating chamber 24 is not limited to the above-mentioned shape and can be changed to any shape. Unlike the present embodiment, the number of partition walls 44 may not be one, and multiple partition walls may be provided. If possible, the step 51 may be omitted.

[0041] Incidentally, since blowby gas flows into the heating chamber 24, the oil contained in the blowby gas may gradually accumulate in the heating chamber 24 through continuous use. Furthermore, the accumulated oil may disrupt the originally planned flow of blowby gas into the heating chamber 24.

[0042] In the present embodiment, blowby gas, from which the oil has been separated by the oil separator 22, flows into the heating chamber 24. Therefore, the oil content of blowby gas in the heating chamber 24 is relatively small. Nevertheless, an unacceptable amount of oil may accumulate in the heating chamber 24 over a long period of time.

[0043] For this reason, in the present embodiment, a drain mechanism 60 for draining oil accumulated in the heating chamber is provided in the heating chamber 24. As a result, it is possible to drain the oil accumulated in the heating chamber 24 and solve problems caused by accumulated oil (for example, the problem that accumulated oil interferes with a desired flow of blowby gas into the heating chamber 24).

[0044] As in Fig. 2 and Fig. As shown in Figure 3, the drain mechanism 60 is provided at the lowest position of the heating chamber 24, specifically at the lower left corner, and is capable of draining as much of the oil accumulated in the heating chamber 24 as possible. The drain mechanism 60 includes a drain valve that can be opened and closed. The drain valve prevents oil from being drained when the drain valve is closed and allows oil to be drained when the drain valve is open. In the present embodiment, the drain valve is a check valve 61.

[0045] At the lowermost position of a left wall portion 62 forming a left inner wall surface 46 of the heating chamber 24, a horizontal drain hole 63 is formed through the left wall portion 62. The check valve 61 is fixed to an outer surface of the left wall portion 62 by suitable means, such as welding, screwing, or the like, to communicate with the drain hole 63.

[0046] The check valve 61 includes a main valve body 64 fixed to the left wall part 62, a valve hole 65 formed by the main valve body 64, a valve body chamber 66 provided in the center of the valve hole 65 so that the diameter of the valve hole 65 expands, a valve body 67 in which the valve body chamber 66 is arranged, and a spring 68 serving as a biasing member that biases the valve body 67 toward a valve closing side.

[0047] The valve hole 65 communicates coaxially with the drain hole 63 and extends in the left-right direction and the horizontal direction. The valve body 67 is a metal ball, such as an iron ball. The spring 68 urges the valve body 67 toward the left side, which is the opposite side to the heating chamber 24, to thereby close the shutoff valve 61. Therefore, in the example shown in the drawing, the left side, which is the opposite side to the heating chamber 24, is the valve closing side, and the right side, which is close to the heating chamber 24 side, is the valve opening side. The spring 68 is a coil spring.

[0048] Meanwhile, as in Fig. 2, the check valve 61 is accessible through a hole provided in the flywheel housing 10, i.e., a housing hole 70. The housing hole 70 is specifically a maintenance hole for performing a visual inspection of the inside of the flywheel housing 10, etc., after assembly, and is usually blocked with a removable dowel 71, such as a screw-in dowel. When the dowel 71 is removed, it becomes possible to access the check valve 61 from the outside of the flywheel housing 10. The valve hole 65 is positioned in the housing hole 70 on its left side.

[0049] The flow of the blow-by gas in the configuration of the present embodiment is as shown by the arrows in Fig. 1 and Fig. 2. Blow-by gas separated from the oil by the oil separator 22 flows into the heating chamber 24 through the upstream gas line 25 and the introduction port 30. In the heating chamber 24, as shown in Fig. 2, the blowby gas discharged from the introduction port 30 enters the lower space 50 linearly and smoothly through the gap 48. The blowby gas first moves to the left side in the lower space 50, makes a U-turn to the right side, rises in the gap 48, and enters an upper space 52 partitioned by the partition wall 44. Then, the blowby gas moves to the left side in the upper space 52 and is discharged from the discharge port 32 into the downstream gas line 26. Thereafter, the blowby gas flows through the downstream gas line 26 and is discharged into the outside air through the outlet part 33 (i.e., released into the atmosphere).

[0050] As described above, it is possible to cause the blowby gas to meander in the heating chamber 24, thereby causing the blowby gas to remain temporarily.

[0051] Relatively high-temperature oil in the gear chamber 14, which lubricates the gear mechanism 13, adheres to the flywheel housing 10 and the cover 41, so that the flywheel housing 10 and the cover 41 are heated by the oil. Therefore, due to this heat, it is possible to heat the blowby gas in the heating chamber 24 to keep it warm, or at least to prevent its temperature from dropping. Therefore, it is possible to prevent the generation of condensed water due to the condensation of moisture contained in the blowby gas, the freezing of condensed water in the gas line 23, and the blockage of the inside of the gas line 23 due to freezing. Since the blowby gas is caused to meander and remain in the heating chamber 24, a long heating time is ensured, and this is beneficial to preventing the generation of condensed water and so on.

[0052] Since blowby gas flows particularly toward the downstream side of the gas line 23 exposed to the outside air, it is likely to be cooled by the outside air, and its temperature decreases. The most notable part is the outlet part 33 of the downstream gas line 26, where the temperature of the blowby gas decreases the most. Meanwhile, the outside air, including a traveling wind, entering the outlet part 33, and in a cold area, for example, the outside air entering the outlet part 33 is also very cold. Under such circumstances, condensation and freezing are likely to occur in the outlet part 33.

[0053] However, according to the configuration of the present embodiment, since blow-by gas can be heated by the heating chamber 24 provided in the middle of the gas line 23, the temperature of the blow-by gas reaching the outlet part 33 is raised, so that it is possible to effectively prevent the generation and freezing of condensed water in the outlet part 33.

[0054] According to the configuration of the present embodiment, since the heating chamber 24 is formed by the cavity 40 integrally formed with the flywheel housing 10 and the lid 41 closing the cavity 40, it is also possible to easily form the heating chamber compared to a case where a heating chamber, which is a completely enclosed space, is formed in the flywheel housing. Since the lid 41 is detachable, it is also possible to remove the lid 41 to inspect and maintain the inside of the heating chamber 24 when necessary. The lid 41 can also be considered as a part of the separate flywheel housing 10.

[0055] However, the heating chamber, which is the completely enclosed space, may be formed in the flywheel housing.

[0056] Incidentally, in the present embodiment, when oil accumulates in the heating chamber 24 through continuous use, it is possible to discharge the accumulated oil through the discharge mechanism 60.

[0057] As in Fig. 4, when the oil O accumulates in the heating chamber 24, a maintenance mechanic removes the dowels 71 and inserts a jig or tool 72 into the flywheel housing 10 through the housing hole 70. Then, the maintenance mechanic inserts a tip of the tool 72 into the valve hole 65 and pushes the tool 72 toward the valve opening side (the right side), so that the valve body 67 is pushed out against the biasing force of the spring 68 by the tip of the tool 72, thereby opening the check valve 61.

[0058] As a result, the oil O is discharged from the heating chamber 24 through the drain hole 63 and the valve hole 65 in sequence. The discharged oil O may fall into the flywheel housing 10. However, although the discharged oil falls, since the inside of the flywheel housing 10 is also oily and the amount of oil is very small, there is a problem.

[0059] According to the configuration of the present embodiment, even though oil accumulates in the heating chamber 24, it is possible to regularly discharge the oil at the time of maintenance, thereby solving problems caused by oil accumulation while preventing oil accumulation. Also, since it is possible to discharge oil simply by inserting the tool 72 through the housing hole 70 and pressing the valve body 67 with the tip of the tool 72, it is possible to easily perform the oil discharge work.

[0060] Modifications will now be described. Incidentally, parts identical to those of the basic example described above are denoted by the same reference numerals, and a description thereof will be omitted. Hereinafter, differences from the basic example will be mainly described.

[0061] In a first in Fig. In the modification shown in Figure 5, the valve body 67 of the check valve 61 is a cylindrical hollow piston with a bottom. The left end of the valve body 67 is closed and pressed against a valve seat 69 by the spring 68. The right end of the valve body 67 is opened, and the spring 68 is inserted into the valve body 67 thereof.

[0062] In a Fig. In the second modification shown in Fig. 6, the drain valve is a drain plug 75. The drain plug 75 is tightened to an inner screw 76 provided on an inner surface of an outlet part of the valve hole 65 and blocks the valve hole 65. As a result, the drain valve comes into the closed state. The drain plug 75 is a general hexagonal bolt having a hexagonal head 77 and is tightened to the inner screw 76 with a washer 78 interposed therebetween. When the drain plug 75 is loosened, oil leaks from the gap between the drain plug 75 and the inner screw 76 and is discharged. Therefore, the valve hole 65 essentially comes into the open state, and the drain valve comes into the open state. As described above, the drain plug 75 is switched between the closed state and the open state by tightening and loosening, so it can be regarded as a drain valve.

[0063] When draining oil from the heating chamber 24, a socket wrench (not shown in the drawing) is inserted into the flywheel housing 10 through the housing hole 70, and a female part of the socket wrench is fitted onto the head 77. Then, the socket wrench is rotated to loosen the drain screw 75, causing the drain valve to open and draining oil.

[0064] In a report prepared in parts (A) and (B) by Fig. In the third modification shown in Figure 7, the drain plug 75 is a general hexagon socket cylinder head screw having a hexagon hole 79. When draining oil from the heating chamber 24, a hexagon wrench is inserted through the housing hole 70, and the drain plug 75 is loosened by the hexagon wrench.

[0065] In a report prepared in parts (A) and (B) by Fig. In the fourth modification shown in Figure 8, the drain plug 75 is also a hexagon socket head cap screw. A groove 81 is provided in an external screw portion 80 of the drain plug 75 and extends in the axial direction. According to this configuration, when the drain plug 75 is loosened, it is possible to allow oil to flow more aggressively through the groove 81, thus making it possible to drain oil more quickly. Since the groove 81 is longer than the inner screw 76, when the drain plug 75 is loosened so that the groove 81 extends from a position beyond the inner screw 76 on the heating chamber 24 side to a position beyond the inner screw 76 on the opposite side of the heating chamber 24, it is possible to drain oil quickly using the inner screw 76 as a shortcut. The groove 81 can be applied to any drain plugs including the drain plug 75 of the second modification ( Fig. 6).

[0066] In a Fig. 9, the discharge mechanism 60 is a check valve 82. However, unlike the basic example, this check valve 82 is of the gravity type and not of the spring type ( Fig. 3).

[0067] That is, a valve body 83 of the check valve 82 rests on a valve seat 84 due to its own weight when the engine is stopped, thereby closing the check valve 82. On the other hand, when the engine is running, due to the pressure in the flywheel chamber 11 increased by rotation of the flywheel 8, the valve body 83 rises as shown by an imaginary line, separating the valve body from the valve seat 84 and opening the check valve 84. Therefore, it is possible to discharge oil when the engine is running.

[0068] In the present modification, at the lowest position of a lower wall portion 85 constituting a lower inner wall surface 49 of the heating chamber 24, a vertical drain hole 86 is formed through the lower wall portion 85. The check valve 82 is fixed to an outer surface of the lower wall portion 85 by suitable means such as welding, screwing, or the like to communicate with the drain hole 86.

[0069] The check valve 82 includes a main valve body 87 fixed to the lower wall portion 85, a valve hole 88 formed by the main valve body 87, a valve body chamber 89 provided in the center of the valve hole 88 so that the diameter of the valve hole 88 expands, and a valve body 83 arranged to be vertically movable in the valve body chamber 89. The valve hole 88 communicates coaxially with the drain hole 86 and extends in the vertical direction. The valve body 83 has a plate shape. The valve seat 84 and the peripheral edge of the lower end of the valve body 83, which sits on the valve seat, have a tapered shape.

[0070] The embodiments of the present disclosure have been described in detail above. However, other embodiments of the present disclosure are also possible.

[0071] (1) For example, the oil separator 22 may be omitted. In this case, oil accumulates in the heating chamber 24 for a shorter time, but it is possible to discharge the accumulated oil through the drain mechanism.

[0072] (2) The mounting position of the drain mechanism can be changed to a position other than the above-mentioned position.

[0073] The configurations of the embodiments and the modifications described above may be partially or completely combined unless there is any specific conflict. Embodiments of the present disclosure are not limited to the embodiments described above, and modifications, applications, and equivalents may also be included in the present disclosure. Therefore, the present disclosure should not be interpreted in a limited manner and may also be applied to any other technologies within the scope of the present disclosure. INDUSTRIAL APPLICABILITY

[0074] According to the present disclosure, it is possible to prevent freezing of condensed water in a blow-by gas line. LIST OF REFERENCE SYMBOLS 1 internal combustion engine (engine) 10 flywheel housing 23 Gas pipeline 24 heating chamber 33 Outlet part 60 Drain mechanism 61 check valve 67 valve body 68 spring 70 housing hole 75 drain plug

Claims

[1] Blow-by gas discharge device, comprising: a blow-by gas line (23) extending from a height position of an upper end part of an internal combustion engine (1) to a height position of a lower end part of the internal combustion engine (1), the blow-by gas line (23) being exposed to outside air and having an outlet part (33) released to an atmosphere; a heating chamber (24) provided in a center of the blowby gas line (23) and in a flywheel housing (10) of the internal combustion engine (1), the heating chamber (24) being configured to heat blowby gas; and a drain mechanism (60) provided in the heating chamber (24) and configured to drain oil accumulated in the heating chamber (24), and comprising a drain valve configured to prevent the oil from being drained when the drain valve is closed and to allow the oil to be drained when the drain valve is open, the drain valve being accessible through a hole (70) provided in the flywheel housing (10). [2] The blow-by gas discharge device according to claim 1, wherein the discharge valve is a check valve (61), and the check valve (61) comprises a valve body (67) and a biasing member configured to bias the valve body (67) toward a valve closing side. [3] Blow-by gas discharge device according to claim 1, wherein the discharge valve is a drain screw (75).

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