Engine and flywheel housing

Abstract

To provide a technology which enables a blow-by gas to be discharged to the outside of a cylinder block properly while avoiding increasing the size of an engine.SOLUTION: An exemplary engine includes: a cylinder block having cylinders each forming a combustion chamber; a crank shaft disposed within the cylinder block; a flywheel attached to one end of the crank shaft; and a flywheel housing which is disposed at one end surface side as seen in a crank axis direction of the cylinder block and houses the flywheel. The flywheel housing has a blow-by gas passage through which a blow-by gas passes.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an engine and a flywheel housing. [Background technology]

[0002] Conventionally, there is known a technology for efficiently discharging blow-by gas that flows from a combustion chamber into the internal space of a crankcase (cylinder block) to the outside of the crankcase (see, for example, Patent Document 1). The crankcase of Patent Document 1 includes a blow-by gas passage formed inside the crankcase and discharging the blow-by gas inside the crankcase to an upper portion of the crankcase. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-140104 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the outlet of the blow-by gas passage is provided on the upper surface of the crankcase. Usually, the upper surface of the crankcase has almost no free space because the cylinder head, the intake manifold, etc. are arranged thereon. For this reason, it is not easy to install a gas pipe for directing the blow-by gas from the blow-by gas passage to another location. If a gas pipe is to be installed that is connected to the blow-by gas outlet provided on the upper surface of the crankcase, measures such as lengthening the overall length of the crankcase are required to avoid contact with the cylinder head, etc. If the overall length of the crankcase is increased, there is a concern that the engine will become larger.

[0005] An object of the present invention is to provide a technique that can properly discharge blow-by gas outside a cylinder block while avoiding an increase in the size of an engine. [Means for solving the problem]

[0006] An exemplary engine of the present invention includes a cylinder block having cylinders that define combustion chambers, a crankshaft disposed within the cylinder block, a flywheel attached to one end of the crankshaft, and a flywheel housing disposed on one end face side of the cylinder block in the crankshaft direction and accommodating the flywheel. The flywheel housing has a blow-by gas passage through which blow-by gas passes. Effect of the Invention

[0007] According to the exemplary embodiment of the present invention, blow-by gas can be appropriately discharged to the outside of the cylinder block while avoiding an increase in the size of the engine. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view showing the configuration of an engine. [Diagram 2] FIG. 2 is a schematic perspective view showing a portion of the engine that is composed of a cylinder block, a head block, and a head cover. [Diagram 3] Schematic cross-sectional view of a cylinder block portion of an engine. [Figure 4] Schematic top view showing the engine configuration [Diagram 5] FIG. 1 is a schematic perspective view showing elements constituting a discharge path of blow-by gas; [Figure 6] FIG. 2 is a schematic perspective view showing the configuration of a cylinder block. [Figure 7] FIG. 2 is a schematic perspective view showing a configuration of a flywheel housing; [Figure 8] FIG. 8 is a schematic perspective view of a flywheel housing as viewed from a different direction from that in FIG. 7; [Figure 9] Diagram to explain the flow of blow-by gas DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the following description, the X direction is the front-rear direction, the Y direction is the left-right direction, and the Z direction is the up-down direction. The +X side is the front side, and the -X side is the rear side. The +Y side is the right side, and the -Y side is the left side. The +Z side is the upper side, and the -Z side is the lower side. In detail, the direction in which the center line C of the crankshaft (output shaft) shown in FIG. 1 extends is the front-rear direction, and the side where the flywheel 2 is arranged with respect to the cylinder block 1 is the rear side. In addition, the up-down direction is defined as the side where the oil pan 3 is arranged with respect to the cylinder block 1 is the lower side. The direction perpendicular to the front-rear direction and the up-down direction is defined as the left-right direction, and the side that is the right side when viewed from the rear toward the front is the right side, and the side that is the left side is the left side. In addition, these directions are names used simply for explanation, and are not intended to limit the actual positional relationship and direction. In this specification, the crankshaft direction is the same as the front-rear direction in which the center line C of the crankshaft extends.

[0010] <1. Engine Overview> Fig. 1 is a schematic perspective view showing a configuration of an engine 100 according to an embodiment of the present invention. The engine 100 is suitable as a marine engine for use in ships, for example. However, the engine 100 is not limited to being a marine engine and may be applied to other applications. The engine 100 is a diesel engine.

[0011] As shown in Fig. 1, engine 100 includes a cylinder block 1, a head block 4, and a head cover 5. Fig. 2 is a schematic perspective view showing a portion of engine 100 that includes cylinder block 1, head block 4, and head cover 5. Fig. 3 is a schematic cross-sectional view of the cylinder block 1 portion of engine 100.

[0012] As shown in FIG. 2 and FIG. 3, a crankshaft 6 and a piston 7 extending in the front-rear direction are disposed inside the cylinder block 1. That is, the engine 100 includes the crankshaft 6 disposed inside the cylinder block 1. The inside of the cylinder block 1 is connected to the inside of an oil pan 3 that stores lubricating oil disposed below. A flywheel 2 (see FIG. 1) is attached to the rear end of the crankshaft 6. That is, the engine 100 includes the flywheel 2 attached to one end of the crankshaft 6. More specifically, the flywheel 2 is attached to one end of the crankshaft 6 that protrudes from the cylinder block 1. The flywheel 2 rotates integrally with the crankshaft 6 and is used to extract power from the engine 100. More specifically, the piston 7 is disposed inside a cylinder 11 formed in the cylinder block 1. The piston 7 is connected to the crankshaft 6 via a connecting rod 71.

[0013] The cylinder block 1 has a cylinder 11 that constitutes a combustion chamber. In detail, the cylinder block 1 has a right cylinder 11R arranged on the right side and a left cylinder 11L arranged on the left side. When viewed from the rear, the right cylinder 11R is cylindrical and inclined to the right side with respect to the vertical direction and extends in an oblique direction. When viewed from the rear, the left cylinder 11L is cylindrical and inclined to the left side with respect to the vertical direction and extends in an oblique direction. The right cylinder 11R and the left cylinder 11L are arranged in a V-shape. The pair of right cylinder 11R and left cylinder 11L arranged in a V-shape are arranged with the cylinder axes slightly shifted in the front-rear direction. In this embodiment, the left cylinder 11L is arranged slightly forward of the right cylinder 11R.

[0014] The cylinder block 1 has a right cylinder row 111R in which a plurality of right cylinders 11R are arranged in the front-rear direction, and a left cylinder row 111L in which a plurality of left cylinders 11L are arranged in the front-rear direction. That is, the cylinder block 1 has two cylinder rows 111R and 111L. In each of the two cylinder rows 111R and 111L, a plurality of cylinders 11 are arranged in the crankshaft direction. The two cylinder rows 111R and 111L are arranged side by side. In addition, the two cylinder rows 111R and 111L are arranged in the left-right direction in detail. The right cylinder row 111R and the left cylinder row 111L form a V-shaped bank. That is, in the engine 100, the two cylinder rows 111R and 111L form a V-bank. In this embodiment, the number of right cylinders 11R that constitute the right cylinder row 111R and the number of left cylinders 11L that constitute the left cylinder row 111L are both six, for example. That is, the engine 100 of this embodiment is a V-type 12-cylinder engine. The cylinder block 1 only needs to have at least one cylinder 11 on each of one side and the other side in a direction intersecting with the crankshaft direction. The cylinders 11 on the one side and the other side only need to form a V-bank. The one side and the other side in a direction intersecting with the crankshaft direction may be the right side and the left side.

[0015] In each of the right cylinder row 111R and the left cylinder row 111L, a head block 4 is disposed overlapping each cylinder 11. The head block 4 is fastened to the cylinder block 1 using a screw. In detail, the head block 4 includes a right head block 4R overlapping the right cylinder 11R and a left head block 4L overlapping the left cylinder 11L. The right head blocks 4R are overlapped one by one on each of the right cylinders 11R, so that there are as many right cylinders 11R as there are right cylinders 11R. The left head blocks 4L are overlapped one by one on each of the left cylinders 11L, so that there are as many left cylinders 11L as there are left cylinders 11L. In this embodiment, the number of right head blocks 4R and left head blocks 4L is six.

[0016] Each head block 4 has an intake port 41 for supplying gas to a combustion chamber formed by the cylinder 11, piston 7, and head block 4, and an exhaust port (not shown) for exhausting gas from the combustion chamber. The exhaust port is provided on the surface opposite to the surface on which the intake port 41 is provided. In detail, the right head block 4R has an intake port 41 on its left side surface and an exhaust port on its right side surface. The left head block 4L has an intake port 41 on its right side surface and an exhaust port on its left side surface.

[0017] A head cover 5 is placed on top of each head block 4. The head cover 5 is fastened to the head block 4 with screws. Each head cover 5 covers an intake valve and an exhaust valve (not shown) arranged on the head block 4. An injector 8 is attached to each head cover 5. One end of the injector 8, which is provided with an injection port for injecting fuel, faces the combustion chamber. The other end of the injector 8 protrudes from the head cover 5 towards the outside.

[0018] In detail, the head cover 5 includes a right head cover 5R that is placed on the right head block 4R and a left head cover 5L that is placed on the left head block 4L. The right head covers 5R are placed on each right head block 4R, so there are the same number of right head covers 5R as the number of right head blocks 4R. The left head covers 5L are placed on each left head block 4L, so there are the same number of left head blocks 4L. In this embodiment, the number of right head covers 5R and left head covers 5L is six. The number of right injectors 8R arranged on the right head cover 5R and the number of left injectors 8L arranged on the left head cover 5L are also six.

[0019] On the right side of the cylinder block 1, the right cylinder 11R, the right head block 4R, and the right head cover 5R that constitute the right bank RB extend obliquely upward to the right. On the left side of the cylinder block 1, the left cylinder 11L, the left head block 4L, and the left head cover 5L that constitute the left bank LB extend obliquely upward to the left. In a plan view from the front-rear direction, the right bank RB and the left bank LB are V-shaped, and the engine 100 has a V-bank. An intra-bank area 200 is formed between the right bank RB and the left bank LB in the left-right direction.

[0020] Returning to FIG. 1, the engine 100 includes a top cover 9 and a side cover 10. The top cover 9 prevents water from splashing on the controller 26 (see FIG. 4, etc., described later) and other components disposed inside the engine 100 due to, for example, condensation. The side cover 10 prevents fuel from scattering due to, for example, cracks in components such as the head block 4. Although FIG. 1 only shows the side cover 10 disposed on the right side, a similar side cover 10 is also disposed on the left side. That is, the engine 100 includes a pair of left and right side covers 10.

[0021] Fig. 4 is a schematic top view showing the configuration of an engine 100 according to an embodiment of the present invention. The top cover 9 and the pair of side covers 10 are omitted in Fig. 4. As shown in Figs. 1 and 4, the engine 100 includes an intake manifold 21 and an exhaust manifold 22.

[0022] The intake manifold 21 distributes intake air, which is air or a mixture drawn in from the outside, to each cylinder 11. The intake manifold 21 is disposed on the upper part of the engine 100 and extends in the front-rear direction. In detail, the intake manifold 21 includes a right intake manifold 21R for the right cylinder 11R and a left intake manifold 21L for the left cylinder 11L. That is, the engine 100 includes two intake manifolds 21R, 21L.

[0023] The right intake manifold 21R is disposed above the intake ports 41 (see FIG. 2) of the multiple right head blocks 4R aligned in the front-rear direction. The interior of the right intake manifold 21R is connected to each of the right cylinders 11R via each of the intake ports 41. The left intake manifold 21L is disposed above the intake ports 41 of the multiple left head blocks 4L aligned in the front-rear direction. The interior of the left intake manifold 21L is connected to each of the left cylinders 11L via each of the intake ports 41.

[0024] In more detail, an intake valve (not shown) is interposed between each intake port 41 and each cylinder 11, and when the intake valve is opened, the inside of the intake manifold 21 and the cylinder 11 communicate with each other.

[0025] The exhaust manifold 22 collects exhaust from each cylinder 11. The exhaust manifold 22 is disposed on a side portion of the engine 100 and extends in the front-rear direction. In detail, the exhaust manifold 22 includes a right exhaust manifold 22R for the right cylinder 11R and a left exhaust manifold 22L for the left cylinder 11L.

[0026] The right exhaust manifold 22R is disposed on the right side of multiple right head blocks 4R (see FIG. 2) arranged in the front-rear direction. The interior of the right exhaust manifold 22R and each right cylinder 11R are connected via exhaust ports (not shown) provided on the right side of the right head block 4R. The left exhaust manifold 22L is disposed on the left side of multiple left head blocks 4L (see FIG. 2) arranged in the front-rear direction. The interior of the left exhaust manifold 22L and each left cylinder 11L are connected via exhaust ports (not shown) provided on the left side of the left head block 4L.

[0027] In more detail, an exhaust valve (not shown) is interposed between each exhaust port and each cylinder 11, and when the exhaust valve is opened, the inside of the exhaust manifold 22 and the cylinder 11 communicate with each other.

[0028] The exhaust gas collected in the right exhaust manifold 22R is exhausted to the outside via a right supercharger 23R and a right exhaust outlet pipe 24R arranged at the right rear of the engine 100. The exhaust gas collected in the left exhaust manifold 22L is exhausted to the outside via a left supercharger 23L and a left exhaust outlet pipe 24L arranged at the left rear of the engine 100.

[0029] The right turbocharger 23R and the left turbocharger 23L each have a compressor section 231 and a turbine section 232. The compressor section 231 pressurizes and compresses intake air such as air supplied from outside the engine 100. The pressurized and compressed intake air is supplied to the intake manifold 21 via the intercooler 25. The turbine section 232 is rotated by exhaust gas supplied from the exhaust manifold 22. The rotational power of the turbine section 232 is transmitted to the compressor section 231. That is, the right turbocharger 23R and the left turbocharger 23L of this embodiment are so-called turbochargers that use an exhaust gas turbine as a drive source.

[0030] The intercooler 25 connected to the intake manifold 21 is supplied with cooling water by a cooling water pump (not shown) and cools the intake air. The intake air supplied from the compressor unit 231 is pressurized and compressed, generating compression heat and increasing the temperature. The intercooler 25 cools the intake air by exchanging heat between the cooling water supplied from the cooling water pump and the pressurized and compressed intake air. In other words, by providing the intercooler 25, the temperature of the intake air supplied to the intake manifold 21 can be adjusted to a desired temperature.

[0031] As shown in Fig. 4, the right intake manifold 21R and the left intake manifold 21L are arranged at a distance from each other in the left-right direction on the upper part of the engine 100. As shown in Fig. 4, when the top cover 9 is removed, the in-bank area 200 is exposed to the outside through the space between the right intake manifold 21R and the left intake manifold 21L. In the in-bank area 200, for example, a controller 26 that controls the entire engine 100, a fuel pump 27 that supplies fuel to the injector 8, etc. are arranged.

[0032] That is, the engine 100 includes a controller 26 disposed in an intra-bank area 200 located between the right cylinder row 111R and the left cylinder row 111L. The engine 100 also includes a fuel pump 27 disposed in the intra-bank area 200. Note that, strictly speaking, the intra-bank area 200 may be the spatial area between the right cylinder row 111R and the left cylinder row 111L. However, in this embodiment, the intra-bank area 200 broadly includes the spatial area in the left-right direction between the right bank RB including the right cylinder row 111R and the left bank LB including the left cylinder row 111L.

[0033] By arranging the controller 26 and the fuel pump 27 in the in-bank area 200, the in-bank area 200 can be efficiently used for arranging parts, thereby making it possible to reduce the size of the engine 100. However, the controller 26 and the fuel pump 27 may be arranged outside the in-bank area 200.

[0034] In addition, the controller 26 specifically includes a first controller 261 and a second controller 262. However, the number of controllers 26 may be changed as appropriate, and for example, the controller 26 may be configured with only one controller. In this embodiment, the first controller 261 and the second controller 262 are arranged in the front-rear direction (crankshaft direction). In detail, the first controller 261 is located forward of the second controller 262. One of the first controller 261 and the second controller 262 is a main controller, and the other is a sub-controller. In this embodiment, the first controller 261 is a main controller, and the second controller 262 is a sub-controller.

[0035] The first controller 261 configured as a main controller executes calculations necessary for controlling the engine 100. The calculations necessary for controlling the engine 100 include, for example, calculations related to control of fuel injection and calculations related to stopping the engine 100. The second controller 262 configured as a sub-controller is connected to the first controller 261 by a communication line (not shown) and is provided so as to be able to communicate with the first controller 261. The second controller 262 performs control operations according to instructions from the first controller 261.

[0036] The first controller 261 controls the right injector 8R arranged in the right bank RB. That is, the first controller 261 and each right injector 8R are electrically connected. The second controller 262 controls the left injector 8L arranged in the left bank LB. That is, the second controller 262 and each left injector 8L are electrically connected.

[0037] In addition, the fuel pump 27 pressurizes the fuel and discharges it toward a high-pressure fuel pipe (not shown) for the right bank RB and a high-pressure fuel pipe (not shown) for the left bank LB. The fuel passing through the high-pressure fuel pipe for the right bank RB is distributed to each right injector 8R arranged in the right bank RB. The fuel passing through the high-pressure fuel pipe for the left bank LB is distributed to each left injector 8L arranged in the left bank LB. Each injector 8 injects fuel into the combustion chamber under the control of the controller 26.

[0038] <2. Blow-by gas exhaust> The engine 100 includes a path (hereinafter simply referred to as a discharge path) for discharging blow-by gas leaking from the combustion chamber from within the cylinder block 1. The blow-by gas contains unburned gas, burned gas, and oil vapor.

[0039] 5 is a schematic perspective view showing elements constituting the exhaust path of blow-by gas provided in the engine 100 according to the embodiment of the present invention. As shown in FIG. 5, the elements constituting the exhaust path of blow-by gas include a cylinder block 1, a flywheel housing 28, a gas pipe 29, and an oil separator 30. In other words, the engine 100 includes the cylinder block 1, the flywheel housing 28, the gas pipe 29, and the oil separator 30.

[0040] FIG. 6 is a schematic perspective view showing the configuration of a cylinder block 1 included in an engine 100 according to an embodiment of the present invention. As described above, the cylinder block 1 includes two cylinder rows 111R and 111L that form a V-bank, and extends in the crankshaft direction (front-rear direction). The cylinder block 1 has an internal space 1a (hereinafter referred to as the block space 1a). In addition to the crankshaft 6 described above, for example, a camshaft 33 (see FIG. 9 described later) and the like are arranged in the block space 1a. Camshaft holes 1b through which the camshafts pass are provided in the front and rear surfaces of the cylinder block 1. In addition, the cylinder block 1 is provided with a plurality of shaft insertion holes 1c through which a control shaft (neither of which is shown in the figures) that is paired with the camshaft 33 to control the opening and closing of the intake valve or the exhaust valve passes.

[0041] Blow-by gas leaking from the combustion chambers formed for each cylinder 11 enters the block intraspace 1a. The cylinder block 1 has an exhaust port 1d for exhausting the blow-by gas on one end face in the crankshaft direction. More specifically, the exhaust port 1d is provided on the rear face of the cylinder block 1. The exhaust port 1d is provided to exhaust the blow-by gas leaking from the combustion chambers into the block intraspace 1a to the outside of the block intraspace 1a. In this embodiment, the exhaust port 1d is provided on the upper part of the rear face of the cylinder block 1. The exhaust port 1d is provided above the crankshaft 6 (see FIG. 9 described later). The exhaust port 1d is provided further above the camshaft hole 1b, which is provided above the crankshaft 6.

[0042] In this embodiment, as shown in Fig. 6, the cylinder block 1 has two openings 1e on the top surface located between the two cylinder rows 111R and 111L in the left-right direction. These openings 1e are covered by a block top cover 34 (see Fig. 9 described later). In other words, blow-by gas is not discharged to the outside of the block internal space 1a through these two openings 1e. Two openings 1e do not necessarily have to be provided.

[0043] The flywheel housing 28 is disposed on one end face side of the cylinder block 1 in the crankshaft direction. The flywheel housing 28 accommodates the flywheel 2 (see FIG. 1). More specifically, the flywheel housing 28 is disposed on the rear face side of the cylinder block 1. The flywheel housing 28 is attached to the cylinder block 1. In this embodiment, the flywheel housing 28 is directly attached to the cylinder block 1. That is, the rear face of the cylinder block 1 includes a housing attachment surface 1f to which the flywheel housing 28 is attached. The front face of the flywheel housing 28 includes a block attachment surface 28a (see FIG. 8 described later) to which the cylinder block 1 is attached. When the flywheel housing 28 is attached to the cylinder block 1, the housing attachment surface 1f and the block attachment surface 28a come into contact with each other.

[0044] The rear surface of the cylinder block 1 is provided with a recess 1g that is recessed forward. The rear surface of the cylinder block 1 includes the above-mentioned housing mounting surface 1f that constitutes the outer edge of the recess 1g, and a bottom surface 1h of the recess 1g. The bottom surface 1h of the recess 1g is located forward of the housing mounting surface 1f. The exhaust port 1d is provided in the bottom surface 1h of the recess 1g.

[0045] Fig. 7 is a schematic perspective view showing the configuration of the flywheel housing 28 included in the engine 100 according to the embodiment of the present invention. Fig. 8 is a schematic perspective view of the flywheel housing 28 seen from a different direction than that of Fig. 7. Fig. 7 is a view of the flywheel housing 28 seen from diagonally above the rear right. Fig. 8 is a view of the flywheel housing 28 seen from diagonally above the front right. As shown in Figs. 7 and 8, the flywheel housing 28 has a housing main body portion 281 that houses the flywheel 2, a housing upper piece portion 282, and a housing lower piece portion 283.

[0046] The housing main body 281 has a circular shape in a plan view from the front-rear direction. As shown in FIG. 7, a rear recess 284 recessed forward is provided on the rear surface of the housing main body 281. The rear surface of the housing main body 281 includes a ring-shaped surface 2841 constituting the outer edge of the rear recess 284 and a bottom surface 2842 of the rear recess 284. The bottom surface 2842 of the rear recess 284 is located forward of the ring-shaped surface 2841. A crankshaft hole 285 penetrating the housing main body 281 in the front-rear direction is provided on the bottom surface 2842 of the rear recess 284. The rear end of the crankshaft 6 is inserted into the crankshaft hole 285 and fixed to the flywheel 2 housed in the rear recess 284 (see FIG. 9 and the like described later).

[0047] The housing upper piece 282 extends upward from the housing main body 281. The housing lower piece 283 extends downward from the housing main body 281. As shown in Fig. 8, a front surface recess 286 that is recessed rearward is provided on the front surface of the flywheel housing 28. The front surface recess 286 extends in the vertical direction. The front surface recess 286 extends in a strip shape from the housing upper piece 282 to the housing lower piece 283.

[0048] The front surface of the flywheel housing 28 includes an outer edge surface 2861 that constitutes the outer edge of the front recess 286, and a bottom surface 2862 of the front recess 286. The bottom surface 2862 of the front recess 286 is located rearward of the outer edge surface 2861. The bottom surface 2862 of the front recess 286 is provided with the crankshaft hole 285 described above. The outer edge surface 2861 includes the block mounting surface 28a described above. The outer edge surface 2861 also includes an oil pan mounting surface 28b that is attached to the rear surface of the oil pan 3 that is arranged below the cylinder block 1. The outer edge surface 2861 also includes a support base mounting surface 28c that is attached to the rear surface of the fuel pump support base 31 (see FIG. 5, etc.) that is arranged above the cylinder block 1. The fuel pump support base 31 is a support base that supports the above-mentioned fuel pump 27 that is arranged in the intra-bank area 200.

[0049] 7 and 8, the housing upper half portion 282 is provided with a first upper half portion opening 2821 and a second upper half portion opening 2822 which penetrate the housing upper half portion 282 in the front-rear direction. The first upper half portion opening 2821 and the second upper half portion opening 2822 are aligned in the left-right direction. The first upper half portion opening 2821 is located to the left of the second upper half portion opening 2822. The first upper half portion opening 2821 and the second upper half portion opening 2822 are connected to the front recess 286.

[0050] It should be noted that the housing upper half 282 may be configured to have only one opening. In this embodiment, the second upper half opening 2822 is provided so that the number of rotations can be measured with a revolution counter. As shown in Fig. 5, the second upper half opening 2822 is covered by the opening cover 32 during normal use. If it is not necessary to measure the number of rotations, the second upper half opening 2822 does not have to be provided.

[0051] Fig. 9 is a diagram for explaining the flow of blow-by gas in the engine 100 according to the embodiment of the present invention. Fig. 9 is a schematic cross-sectional perspective view showing some parts of the engine 100. In Fig. 9, the outline arrows indicate the flow of blow-by gas. As shown in Fig. 9, the blow-by gas that leaks from the combustion chamber and enters the block internal space 1a is discharged to the outside of the block internal space 1a through the discharge port 1d.

[0052] The exhaust port 1d is connected to a front recess 286 of the flywheel housing 28 when the flywheel housing 28 is attached to the cylinder block 1. That is, the blow-by gas discharged from the exhaust port 1d enters the front recess 286. As shown in Fig. 9, the blow-by gas that has entered the front recess 286 is discharged toward the rear of the flywheel housing 28 through a first upper piece opening 2821 that is located above the exhaust port 1d.

[0053] In addition, the blow-by gas that enters the front recess 286 from the exhaust port 1d passes through the space surrounded by the rear surface of the fuel pump support base 31 located in front of the flywheel housing 28 and the surface that constitutes the front recess 286, and reaches the first upper piece opening 2821.

[0054] That is, the flywheel housing 28 has a blow-by gas passage GP through which the blow-by gas leaking from the combustion chamber passes. In this embodiment, the blow-by gas passage GP includes the front recess 286 and the first upper piece opening 2821. The exhaust port 1d communicates with the blow-by gas passage GP.

[0055] By configuring the blow-by gas passage GP to be provided in the flywheel housing 28, an exhaust port 1d for exhausting the blow-by gas can be provided on one end surface of the cylinder block 1 in the crankshaft direction. This makes it possible to eliminate measures that would be required when arranging the exhaust port for the blow-by gas on the upper surface of the cylinder block 1. For example, it is possible to eliminate the need to increase the length of the cylinder block 1 in the crankshaft direction in order to secure a place to arrange the exhaust port. As a result, it is possible to avoid an increase in size of the engine 100. In addition, according to this configuration, a gas pipe for guiding the blow-by gas discharged from the cylinder block 1 to another location can be arranged on one end surface side in the crankshaft direction of the engine 100. As a result, it is possible to easily arrange the gas pipe for flowing the blow-by gas while avoiding interference with the components constituting the engine 100.

[0056] 5, the blow-by gas discharged rearward from the first upper half opening 2821 flows through the gas pipe 29 and is sent to the oil separator 30. In this embodiment, the gas pipe 29 allows the blow-by gas that has passed through the blow-by gas passage GP to flow toward the V-bank side. In a plan view from above, the gas pipe 29 extends from the position where the first upper half opening 2821 is provided to between the left and right sides of the two intake manifolds 21R, 21L arranged in the intra-bank area 200 (see also FIGS. 1 and 4).

[0057] By configuring the gas pipe 29 to guide the blow-by gas toward the V-bank, a path for discharging the blow-by gas can be formed by effectively utilizing the space inside the engine 100. Also, the oil separator 30 that processes the blow-by gas can be disposed by utilizing the space inside or above the V-bank.

[0058] The oil separator 30 is connected to the gas pipe 29 and separates the oil component contained in the blow-by gas. The oil separator 30 collects and separates oil mist, which is a vaporized lubricating oil component contained in the blow-by gas. That is, the oil separator 30 functions as an oil mist separator. The oil separator 30 discharges the remaining gas, after removing the oil component from the blow-by gas, to the outside through a chimney (not shown). The oil separator 30 also returns the oil component separated from the blow-by gas to the oil pan 3 through an oil piping (not shown).

[0059] The gas remaining after removing the oil component from the blow-by gas may be sent to the intake manifold 21 instead of being discharged to the outside.

[0060] In this embodiment, the oil separator 30 is disposed between the two intake manifolds 21R, 21L disposed in the intra-bank area 200 in a plan view from above (see FIG. 4). That is, the oil separator 30 is disposed to effectively utilize the space generated inside the engine 100.

[0061] In detail, the oil separator 30 includes a right oil separator 30R and a left oil separator 30L arranged side by side in the left-right direction. The right oil separator 30R is disposed to the right of the left oil separator 30L. However, the number of oil separators 30 included in the engine 100 may be changed as appropriate, and may be one or three or more.

[0062] In this embodiment, the gas pipes 29 include a common gas pipe 291, a right gas pipe 292, and a left gas pipe 293. The configuration of the gas pipes 29 may be appropriately changed depending on the number of oil separators 30.

[0063] The common gas pipe 291 has a branch portion 2911, a right pipe portion 2912, and a left pipe portion 2913. The branch portion 2911 is located in the center of the common gas pipe 291, and is attached to the rear surface of the housing upper piece portion 282. The branch portion 2911 covers the first upper piece portion opening 2821. The branch portion 2911 has a recess (not shown) on the front surface that is recessed toward the rear. The recess communicates with the first upper piece portion opening 2821. The right pipe portion 2912 is shaped like a pipe extending rightward from the branch portion 2911, and its interior communicates with the recess of the branch portion 2911. The left pipe portion 2913 is shaped like a pipe extending leftward from the branch portion 2911, and its interior communicates with the recess of the branch portion 2911.

[0064] The right gas pipe 292 has one end connected to the right pipe section 2912 of the common gas pipe 291, and the other end connected to the right oil separator 30R. The left gas pipe 293 has one end connected to the left pipe section 2913 of the common gas pipe 291, and the other end connected to the left oil separator 30L. The right gas pipe 292 extends from the common gas pipe 291 arranged below the intercooler 25 while curving to the space in front of the intercooler 25 and between the two intake manifolds 21R and 21L, and is connected to the right oil separator 30R. The left gas pipe 293 extends from the common gas pipe 291 arranged below the intercooler 25 while curving to the space in front of the intercooler 25 and between the two intake manifolds 21R and 21L, and is connected to the left oil separator 30L.

[0065] The blow-by gas discharged rearward from the first upper half opening 2821 is distributed to the left and right at the branching portion 2911 of the common gas pipe 291. The blow-by gas distributed to the right pipe portion 2912 at the branching portion 2911 passes through the right pipe portion 2912 and the right gas pipe 292 to the right oil separator 30R, where the oil components are removed and the gas is discharged to the outside. The blow-by gas distributed to the left pipe portion 2913 at the branching portion 2911 passes through the left pipe portion 2913 and the left gas pipe 293 to the left oil separator 30L, where the oil components are removed and the gas is discharged to the outside.

[0066] <3. Things to keep in mind> Various technical features disclosed in this specification can be modified in various ways without departing from the spirit of the technical creation. In other words, the above embodiment should be considered to be illustrative in all respects and not restrictive. In addition, multiple embodiments and modifications shown in this specification may be combined to the extent possible.

[0067] In the embodiment described above, the engine 100 is a V-engine, but this is merely an example. The present invention can also be applied to, for example, an in-line engine in which the piston reciprocates vertically, or a horizontally opposed engine in which the piston reciprocates horizontally. [Explanation of symbols]

[0068] 1. Cylinder block 1d...Discharge port 2. Flywheel 6. Crankshaft 11. Cylinder 11R: Right cylinder 11L···Left cylinder 28···Flywheel housing 29. Gas pipe 30. Oil separator 100···Engine 111L: Left cylinder row 111R: Right cylinder row GP···Blow-by gas passage

Claims

1. A cylinder block having a cylinder that defines a combustion chamber; A crankshaft disposed within the cylinder block; A flywheel attached to one end of the crankshaft; a flywheel housing arranged on one end face side of the cylinder block in a crankshaft axis direction and accommodating the flywheel; an oil separator provided outside the flywheel housing and configured to separate an oil component contained in the blow-by gas; Equipped with the flywheel housing has a blow-by gas passage through which the blow-by gas passes, The blow-by gas passage discharges the blow-by gas to the oil separator through a gas pipe.

2. 2. The engine according to claim 1, wherein the cylinder block has, on the one end surface, a discharge port that communicates with the blow-by gas passage and discharges the blow-by gas.

3. the cylinder block has at least one cylinder on each of one side and the other side in a direction intersecting with a crankshaft direction, a V-bank is formed by the cylinders on the one side and the cylinders on the other side, 3. The engine according to claim 1, wherein the gas pipe causes the blow-by gas that has passed through the blow-by gas passage to flow toward the V-bank side.

4. The engine according to claim 3 , wherein the oil separator includes two oil separators arranged side by side on the one side and the other side.

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