Engine

Abstract

To suppress agitation of engine oil due to ventilation of a crankcase.SOLUTION: A partition wall 70 is installed upright on a bottom surface 14A of an oil pan 14, which constitutes a bottom part of an engine crankcase 15, and divides the inside of the oil pan 14 into a first area 71 where engine oil is stored and a second area 72 where engine oil is not stored. An opening 63 for an air introduction passage that guides ventilation air from an intake passage to the crankcase 15 is provided in the second area 72.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an engine with crankcase ventilation. [Background technology]

[0002] As shown in Patent Document 1, an engine is known that is equipped with a ventilation system that introduces air from an intake passage into the crankcase to ventilate blow-by gas within the crankcase. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-185181 Summary of the Invention [Problem to be solved by the invention]

[0004] Engine oil is stored inside the crankcase. Therefore, when air is introduced into the crankcase for ventilation, the blowing of the introduced air can agitate the engine oil. When engine oil is agitated, air bubbles are mixed in, making it more likely to form emulsions. Agitation also makes the engine oil more likely to mist. Some of the misted oil is carried away from the crankcase along with the blow-by gas. Therefore, introducing air for ventilation can increase engine oil consumption. [Means for solving the problem]

[0005] An engine that solves the above problem includes an intake passage, a crankcase in the bottom of which engine oil is stored, a partition wall erected from the bottom of the crankcase to divide the bottom of the crankcase into a first area in which the engine oil is stored and a second area in which the engine oil is not stored, and an air introduction passage having one end opening to the inner wall surface of the crankcase located in the second area and the other end communicating with the intake passage, and is configured to introduce air from the intake passage through the air introduction passage to ventilate the crankcase. [Effects of the Invention]

[0006] The engine has the effect of suppressing engine oil agitation caused by ventilation of the crankcase. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a schematic configuration of an embodiment of an engine. FIG. [Figure 2] FIG. 2 is a side view of the oil pan and its vicinity of the engine. [Figure 3] FIG. 3 is a cross-sectional view showing the cross-sectional structure of the engine taken along line 3-3 in FIG. 2. [Figure 4] 4 is a view of the bulkhead of the engine and its surroundings taken along the arrow A in FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the engine will be described in detail below with reference to FIGS. <About the configuration of Engine 10> First, the configuration of an engine 10 will be described with reference to Figure 1. The engine 10 shown in Figure 1 is a hydrogen engine that generates power by burning hydrogen. In the case of a hydrogen engine, combustible hydrogen may be contained in blow-by gas. For this reason, hydrogen engines are required to have higher blow-by gas ventilation performance than gasoline or diesel engines.

[0009] The engine 10 includes a cylinder block 11. A plurality of cylinders 12 are formed inside the cylinder block 11. Only one of the plurality of cylinders 12 is shown in FIG. 1. Each cylinder 12 accommodates a piston 13 that is capable of reciprocating freely. A combustion chamber 17 for burning hydrogen is formed above the piston 13 in each cylinder 12.

[0010] A cylinder head 16 is attached to the top of the cylinder block 11. Inside the cylinder head 16, individual intake ports 18 and exhaust ports 19 are formed for each cylinder 12. A head cover 16A is attached to the top side of the cylinder head 16. A valve train chamber 20 that houses a valve train mechanism is formed inside the upper part of the cylinder head 16 covered by the head cover 16A.

[0011] An oil pan 14 is attached to the bottom of the cylinder block 11. A crankcase 15 is defined by the skirt portion 11A of the cylinder block 11 and the oil pan 14. The oil pan 14, which forms the bottom of the crankcase 15, stores engine oil.

[0012] The engine 10 is equipped with an intake passage 21, which is a passage through which air is introduced into the combustion chamber 17, and an exhaust passage 22, which is a passage through which exhaust gas is discharged from the combustion chamber 17. An air cleaner 23 is provided in the intake passage 21 to filter dust and the like in the air. A compressor 24 is provided in the intake passage 21 downstream of the air cleaner 23. The compressor 24, together with a turbine 25 provided in the exhaust passage 22, constitutes a turbocharger. An intercooler 26 is provided in the intake passage 21 downstream of the compressor 24. The intercooler 26 is a heat exchanger for cooling air that has been heated by compression in the compressor 24. A throttle valve 27 is provided in the intake passage 21 downstream of the intercooler 26. The throttle valve 27 is a valve for adjusting the flow rate of air sent to the combustion chamber 17 through the intake passage 21. The intake passage 21 branches off for each cylinder 12 at an intake manifold 28 provided downstream of a throttle valve 27. The intake manifold 28 is connected to the combustion chamber 17 through an intake port 18.

[0013] The engine 10 is equipped with an injector 29 that injects hydrogen into the air used for combustion in the combustion chamber 17. In the case of Figure 1, the injector 29 is installed so as to inject hydrogen into the intake port 18, but the injector 29 may also be installed so as to inject hydrogen into the combustion chamber 17. The engine 10 further includes an intake valve 32 that opens and closes the intake port 18 to the combustion chamber 17, and an exhaust valve 33 that opens and closes the exhaust port 19 to the combustion chamber 17.

[0014] <About the ventilation system> The engine 10 is equipped with a ventilation system for the crankcase 15. The ventilation system has three passages, a first passage R1, a second passage R2, and a third passage R3, which connect the intake passage 21 and the crankcase 15.

[0015] The first passage R1 is a passage that connects the crankcase 15 to a portion of the intake passage 21 downstream of the throttle valve 27. The first passage R1 is composed of a blow-by gas passage 40, a first separator 41, a PCV valve 42, a first PCV hose 43, and a second separator 44. The first separator 41 and the second separator 44 are separators that separate oil mist from the blow-by gas flowing through the first passage R1. The first separator 41 is attached to the inside of the head cover 16A. The blow-by gas passage 40 is a passage that passes through the inside of the cylinder block 11 and the cylinder head 16 and connects the crankcase 15 to the first separator 41. The second separator 44 is provided in a portion of the blow-by gas passage 40 in the cylinder block 11. The first PCV hose 43 is a hose that connects the first separator 41 to the intake manifold 28. The PCV valve 42 is a valve that allows gas to flow from the inside of the crankcase 15 to the intake passage 21 through the first passage R1, while restricting gas from flowing from the intake passage 21 to the inside of the crankcase 15 through the first passage R1. The PCV valve 42 is installed at a connection portion of the first PCV hose 43 to the first separator 41.

[0016] The second passage R2 is a passage that connects the crankcase 15 to a portion of the intake passage 21 downstream of the compressor 24. In the case of FIG. 1, the second passage R2 is configured to connect the intake manifold 28 to the crankcase 15. The second passage R2 is composed of a second PCV hose 45 and a one-way valve 60. The second PCV hose 45 is a hose that connects the crankcase 15 to the intake manifold 28. The one-way valve 60 is a valve that allows air to flow from the intake passage 21 to the crankcase 15 through the second passage R2, while restricting the flow of gas from the crankcase 15 to the intake passage 21 through the second passage R2. In the case of the engine 10 of this embodiment, this second passage R2 corresponds to an air introduction passage that has one end that communicates with the intake passage 21 and the other end that opens to the inside of the crankcase 15. In the case of the engine 10 of this embodiment, the one-way valve 60 is attached to the crankcase 15. The details of the attachment structure of the one-way valve 60 to the crankcase 15 will be described later.

[0017] The third passage R3 is a passage that connects the crankcase 15 to a portion of the intake passage 21 upstream of the compressor 24. The third passage R3 is composed of an oil return passage 47, a valve train chamber 20, a third separator 48, and a third PCV hose 49. The oil return passage 47 passes through the interior of the cylinder block 11 and the cylinder head 16 and connects the valve train chamber 20 to the crankcase 15. The oil return passage 47 functions as a passage for returning oil from the valve train chamber 20 to the oil pan 14, and also as a passage for distributing gas between the valve train chamber 20 and the crankcase 15. The third separator 48 is a separator that separates oil mist from the blow-by gas flowing through the third passage R3. The third separator 48 is installed inside the head cover 16A. The third PCV hose 49 is a hose that connects a portion of the intake passage 21 downstream of the air cleaner 23 and upstream of the compressor 24 to the third separator 48.

[0018] When the engine 10 is operating in a naturally aspirated state, the portion of the intake passage 21 downstream of the throttle valve 27 becomes negative pressure. This negative pressure causes blow-by gas in the crankcase 15 to be drawn into the intake passage 21 through the first passage R1. Air is also introduced into the crankcase 15 through the third passage R3. On the other hand, when the engine 10 is operating in a supercharged state, the portion of the intake passage 21 downstream of the compressor 24 becomes positive pressure. At this time, the positively pressurized air is introduced from the intake passage 21 into the crankcase 15 through the second passage R2. The introduced air then pushes out the blow-by gas in the crankcase 15 and releases it into the intake passage 21 through the third passage R3.

[0019] <Installation structure of one-way valve 60> In the engine 10 of this embodiment, the one-way valve 60 that restricts the gas flow direction in the second passage R2 is attached directly to the crankcase 15. The attachment structure of the one-way valve 60 to the crankcase 15 will be described below with reference to FIGS. 2 and 3. FIG. 2 shows a side view of the oil pan 14 of the engine 10 and its vicinity. FIG. 3 shows a cross-sectional structure of the valve housing 50 and its vicinity taken along line 3-3 in FIG. 2.

[0020] In the following description, the state of engine 10 when the vehicle on which engine 10 is mounted is stationary on a horizontal plane will be referred to as the state of engine 10 when mounted on the vehicle. Furthermore, the engine oil level in crankcase 15 when the upper limit of the appropriate range of engine oil is poured into engine 10 when mounted on the vehicle will be referred to as reference oil level OL. Furthermore, the side of one-way valve 60 where the air outlet into crankcase 15 is provided will be referred to as the tip side of one-way valve 60, and the opposite side will be referred to as the base side of one-way valve 60.

[0021] 3, the directions of the upper side when mounted UP, the lower side when mounted DW, the inside case IN, and the outside case OUT are indicated by arrows. The upper side when mounted UP represents the vertically upward direction when the engine 10 is mounted on a vehicle, and the lower side when mounted DW represents the vertically downward direction when the engine 10 is mounted on a vehicle. The inside case IN represents the direction from the outside to the inside of the crankcase 15 in the horizontal direction when mounted, and the outside case OUT represents the direction from the inside to the outside of the crankcase 15 in the horizontal direction when mounted. The horizontal direction when mounted represents the horizontal direction in the cross section shown in FIG. 3 when the engine 10 is mounted on a vehicle.

[0022] As shown in FIG. 2, the engine 10 includes a valve housing 50 for attaching the one-way valve 60 to the crankcase 15. The valve housing 50 is fixed to the outer wall of the oil pan 14 by bolts 51. In the case of FIG. 2, the valve housing 50 is fixed by two bolts 51. The valve housing 50 may also be fixed by one bolt 51, or three or more bolts 51. The valve housing 50 may also be fixed to the crankcase 15 by a method other than the bolts 51. The second PCV hose 45 is connected to the crankcase 15 via the valve housing 50.

[0023] As shown in FIG. 3 , a boss 61 is provided in the oil pan 14 at a mounting portion of the one-way valve 60 and the valve housing 50. An insertion hole 62 that communicates between the inside and outside of the crankcase 15 is formed in the boss 61. The tip end of the one-way valve 60 is inserted into the insertion hole 62. The base end of the one-way valve 60 protruding from the insertion hole 62 is covered by the valve housing 50. The one-way valve 60 is mounted to the crankcase 15 sandwiched between the oil pan 14 and the valve housing 50, which form the outer wall of the crankcase 15. As shown in FIG. 3 , the one-way valve 60 is mounted to the crankcase 15 with its tip facing diagonally downward to avoid interference with surrounding components and to improve the discharge of oil that has entered the interior. Air discharged from the one-way valve 60 passes through the insertion hole 62 and flows into the crankcase 15 without changing direction. Therefore, the opening 63 of the insertion hole 62 in the inner wall of the crankcase 15 corresponds to the opening of the second passage R2 inside the crankcase 15. Air is discharged from the opening 63 into the inside of the crankcase 15 in the direction F shown in the drawing. This direction F is the direction in which the distance to the engine oil surface when the engine 10 is mounted on the vehicle becomes shorter as the air discharge direction moves forward.

[0024] <About bulkhead 70> 3, a partition wall 70 is provided in the oil pan 14 that forms the bottom of the crankcase 15. The partition wall 70 stands upright from the bottom surface 14A of the oil pan 14 that forms the bottom surface of the crankcase 15. The upper end of the partition wall 70 is located above the reference oil level OL (UP) when installed. The upper end of the partition wall 70 is also located above the opening 63 (UP) when installed.

[0025] Fig. 4 shows a view of the partition wall 70 and its surroundings as seen from the arrow A in Fig. 3. The partition wall 70 is formed to surround the opening 63 formed in the inner wall of the crankcase 15. The partition wall 70 may be configured as a member integrated with the oil pan 14, or may be configured as a member separate from the oil pan 14.

[0026] The interior of oil pan 14, which forms the bottom of crankcase 15, is divided into a first region 71 located outside the area surrounded by partition wall 70 and a second region 72 located inside the area. In the case of engine 10 of this embodiment, engine oil is poured into only first region 71 of the two regions.

[0027] <Operation of the embodiment> The engine 10 of this embodiment is provided with a second passage R2 that connects the intake passage 21 with the interior of the crankcase 15. During supercharged operation, the engine 10 ventilates the crankcase 15 by introducing air from the intake passage 21 through the second passage R2.

[0028] The engine 10 includes a partition wall 70 extending from the bottom surface 14A of the crankcase 15. The partition wall 70 divides the bottom of the crankcase 15 into a first region 71 in which engine oil is stored and a second region 72 in which engine oil is not stored. A second passage R2, which serves as a passage for ventilation air, has one end opening to the inner wall surface of the crankcase 15 located within the second region 72 and the other end communicating with the intake passage 21. Therefore, air introduced from the intake passage 21 through the second passage R2 is discharged into the second region 72 in which engine oil is not stored.

[0029] <Effects of the embodiment> The engine 10 of this embodiment has the following advantages. (1) The engine 10 of this embodiment includes a partition wall 70 that divides the bottom of the crankcase 15 into a first region 71 in which engine oil is stored and a second region 72 in which engine oil is not stored. The opening 63 of the second passage R2, which is an air introduction passage that guides air from the intake passage 21 into the interior of the crankcase 15, is located in the second region 72. In this engine 10, air introduced into the crankcase 15 through the second passage R2 is discharged into the second region 72 in which engine oil is not stored. This reduces the agitation of engine oil that occurs when the crankcase 15 is ventilated.

[0030] (2) The blowing of ventilation air onto the engine oil surface can be suppressed by adjusting the position of the opening 63 or the direction of air discharge from the opening 63. However, doing so would limit the mounting position and mounting orientation of the one-way valve 60. In the case of the engine 10 of this embodiment, the partition wall 70 prevents ventilation air from being blown onto the engine oil surface. This increases the degree of freedom in the mounting position and mounting orientation of the one-way valve 60. For example, in the case of the engine 10 of this embodiment, when mounted on a vehicle, the one-way valve 60 is mounted in a position that discharges air diagonally downward toward the inside of the crankcase 15. This prevents the one-way valve 60 from interfering with surrounding components, etc.

[0031] (3) The one-way valve 60 is attached directly to the crankcase 15. More specifically, the engine 10 includes a valve housing 50 fixed to the outer wall of the crankcase 15. The one-way valve 60 is attached to the crankcase 15 while being sandwiched between the crankcase 15 and the valve housing 50. In this engine 10, the one-way valve 60 is warmed by receiving heat from the crankcase 15. This prevents emulsion and freezing in the one-way valve 60 due to low temperatures.

[0032] (Other embodiments) This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0033] The shape of the partition wall 70 may be changed as appropriate as long as it can prevent engine oil from flowing from the first region 71 to the second region 72. The one-way valve 60 may be attached to the crankcase 15 in a position different from that of the above embodiment.

[0034] The mounting structure and mounting position of the one-way valve 60 may be changed. For example, the one-way valve 60 may be mounted directly to the crankcase 15 by screws or the like, without providing the valve housing 50. Also, the one-way valve 60 may be mounted to a location other than the crankcase 15.

[0035] The configuration of the ventilation system for the engine 10 can be modified as appropriate as long as it includes the second passage R2 provided with the one-way valve 60. For example, if ventilation of the crankcase 15 is not required during naturally aspirated operation, the first passage R1 may be omitted.

[0036] The engine 10 may be an engine other than a hydrogen engine. (Additional notes) [Appendix 1] An engine comprising: an intake passage; a crankcase having engine oil stored in its bottom; a partition wall erected from the bottom of the crankcase to divide the bottom of the crankcase into a first area where the engine oil is stored and a second area where the engine oil is not stored; and an air introduction passage having one end opening to an inner wall surface of the crankcase located within the second area and the other end communicating with the intake passage; and the engine ventilating the crankcase by introducing air from the intake passage through the air introduction passage.

[0037] [Appendix 2] An engine as described in Appendix 1, further comprising a one-way valve attached to the crankcase that restricts the flow of gas from the inside of the crankcase toward the intake passage through the air introduction passage.

[0038] [Appendix 3] The engine described in Appendix 2, wherein the one-way valve is mounted in a position such that, when the engine is mounted on a vehicle, it discharges air obliquely downward toward the inside of the crankcase.

[0039] [Supplementary Note 4] The engine according to Supplementary Note 2 or Supplementary Note 3, comprising a valve housing fixed to the outer wall of the crankcase, wherein the one-way valve is attached to the crankcase in a state sandwiched between the outer wall of the crankcase and the valve housing.

Explanation of Signs

[0040] 10 Engine 14 Oil Pan 15 Crankcase 21 Intake Passage 36 Baffle Plate 45 Second PCV Hose 60 One-Way Valve 63 Opening 70 Partition Wall 71 First Region 72 Second Region R2 Second Passage (Air Introduction Passage)

Claims

1. An intake passage; A crankcase in which engine oil is stored at the bottom, a partition wall extending from a bottom surface of the crankcase to divide the bottom of the crankcase into a first region in which the engine oil is stored and a second region in which the engine oil is not stored; an air introduction passage having one end that opens to an inner wall surface of the crankcase located within the second region and the other end that communicates with the intake passage; and ventilating the crankcase by introducing air from the intake passage through the air introduction passage.

2. 2. The engine according to claim 1, further comprising a one-way valve attached to the crankcase to restrict the flow of gas from the inside of the crankcase toward the intake passage through the air introduction passage.

3. 3. The engine according to claim 2, wherein the one-way valve is mounted in a position such that air is discharged obliquely downward toward the inside of the crankcase when the engine is mounted on a vehicle.

4. a valve housing fixed to an outer wall of the crankcase; 3. The engine according to claim 2, wherein the one-way valve is attached to the crankcase in a state where it is sandwiched between an outer wall of the crankcase and the valve housing.

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