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 and subjected to outside air, wherein the blow-by gas line (23) is divided into an upstream gas line (25) and a downstream gas line (26) at a position in the middle thereof; a heating chamber (24) connected between the upstream gas line (25) and the downstream gas line (26) and provided in a flywheel housing (10) of the internal combustion engine (1), the heating chamber (24) being configured to heat blow-by gas; and an oil separator (22) which is provided and configured at the height position of the upper end part of the internal combustion engine (1) to separate oil from the blow-by gas, wherein the upstream gas line (25) has an inlet part (27) connected to the oil separator (22) and an outlet part (29) connected to the heating chamber (24), and the downstream gas line (26) has a further inlet part (31) connected to the heating chamber (24) and a further outlet part (33) released to an atmosphere.

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.

[0003] JP H01-95513 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 and having an outlet portion exposed to the atmosphere. Furthermore, the device comprises a heating chamber provided at a center of the blowby gas line in a flywheel housing of the internal combustion engine and configured to heat blowby gas.

[0004] JP S58-156112 U and JP S58-44418 U describe further blow-by gas discharge devices. SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0005] 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.

[0006] 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.

[0007] The present disclosure provides a blowby gas discharge device having the features of claim 1, which is capable of preventing the 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; and 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 being configured to heat blowby gas.

[0009] The blowby gas discharge device further includes an oil separator provided at the height position of the upper end part of the internal combustion engine and configured to separate oil from the blowby gas, and the blowby gas line may have an inlet part connected to the oil separator.

[0010] At least part of the blowby gas line may be formed of a metal.

[0011] The internal combustion engine may include: a power transmission mechanism configured to transmit power from a crankshaft to a camshaft; and a mechanism chamber accommodating the power transmission mechanism, and wherein the heating chamber may be adjacent to the mechanism chamber. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0012] 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. DESCRIPTION OF THE EMBODIMENTS

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] C1 and C2 each represent a center axis of the crankshaft 6 and a center axis of the camshaft 7.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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 within 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.

[0025] The whole of the gas pipe 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 pipe 23 is divided into two parts at a position in the middle of the height direction, that is, an upstream side gas pipe 25 and a downstream side gas pipe 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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, from which oil has been separated 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).

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] However, the heating chamber, which is the completely enclosed space, may be formed in the flywheel housing.

[0044] The embodiments of the present disclosure have been described in detail above. However, other embodiments of the present disclosure are also possible. (1) For example, the positions of the insertion port 30 and the discharge port 32 may be reversed or changed. (2) The partition wall 44 may be vertically long, not horizontally long, unlike the present embodiment. (3) Part or all of the gas pipe 23 may be formed of a material other than metal, such as rubber or the like. INDUSTRIAL APPLICABILITY

[0045] According to the present disclosure, it is possible to prevent freezing of condensed water in a blowby gas line. LIST OF REFERENCE SYMBOLS 1 internal combustion engine (engine) 10 flywheel housing 13 Gear mechanism 14 Gear chamber 22 oil separators 23 Gas pipeline 24 heating chamber 27 Inlet part 33 Outlet part

Claims

[1] Blow-by gas discharge device, comprising: a blowby 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 blowby gas line (23) being exposed to outside air, the blowby gas line (23) being divided into an upstream side gas line (25) and a downstream side gas line (26) at a position in the middle thereof, ; a heating chamber (24) connected between the upstream gas line (25) and the downstream gas line (26) and provided in a flywheel housing (10) of the internal combustion engine (1), the heating chamber (24) being configured to heat blow-by gas; and an oil separator (22) provided at the height position of the upper end part of the internal combustion engine (1) and configured to separate oil from the blowby gas, wherein the upstream-side gas line (25) has an inlet part (27) connected to the oil separator (22) and an outlet part (29) connected to the heating chamber (24), and the downstream-side gas line (26) has another inlet part (31) connected to the heating chamber (24) and another outlet part (33) released to an atmosphere. [2] A blow-by gas discharge device according to claim 1, wherein at least a part of the blow-by gas line (23) is formed of a metal. [3] A blow-by gas discharge device according to claim 1, wherein a partition wall forming a meandering passage is provided within the heating chamber (24). [4] The blow-by gas discharge device according to claim 1, wherein the internal combustion engine (1) comprises: a power transmission mechanism configured to transmit power from a crankshaft to a camshaft; and a mechanism chamber accommodating the power transmission mechanism, and wherein the heating chamber (24) is adjacent to the mechanism chamber. [5] Blow-by gas discharge device according to claim 2, wherein the internal combustion engine (1) comprises: a power transmission mechanism configured to transmit power from a crankshaft to a camshaft; and a mechanism chamber accommodating the power transmission mechanism, and wherein the heating chamber (24) is adjacent to the mechanism chamber. [6] Blow-by gas discharge device according to claim 3, wherein the internal combustion engine (1) comprises: a power transmission mechanism configured to transmit power from a crankshaft to a camshaft; and a mechanism chamber accommodating the power transmission mechanism, and wherein the heating chamber (24) is adjacent to the mechanism chamber.

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