Internal combustion engine

Abstract

To suppress noise caused by vibration of a plate covering a PCV valve.SOLUTION: An internal combustion engine 100 includes a blow-by gas passage 20. The internal combustion engine 100 further includes a ventilation case 22 provided in the halfway of the blow-by gas passage 20. The internal combustion engine 100 further includes a PCV (positive crankcase ventilation) valve 24 which is provided in the blow-by gas passage 20 and is attached to the ventilation case 22. The PCV valve 24 adjusts an amount of blow-by gas flowing through the blow-by gas passage 20. The internal combustion engine 100 further includes a plate 26 which covers the PCV valve 24 and is attached to the ventilation case 22. The internal combustion engine 100 further includes a cover 28 which covers the plate 26 and comes into contact with a part of the plate 26.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to internal combustion engines. [Background technology]

[0002] Patent Document 1 discloses a PCV (Positive Crankcase Ventilation) valve. The PCV valve is provided in a blow-by gas passage. The PCV valve adjusts the amount of blow-by gas flowing through the blow-by gas passage. The blow-by gas passage is a passage for allowing blow-by gas that has leaked from the combustion chamber of the internal combustion engine into the crankcase to flow into the intake system of the internal combustion engine. The PCV valve is covered with a plate to prevent it from being removed from the internal combustion engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-133607 Summary of the Invention [Problem to be solved by the invention]

[0004] The plate vibrates when the internal combustion engine is running, which can cause noise. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. According to one aspect of the present disclosure, there is provided an internal combustion engine comprising: a blow-by gas passage for flowing blow-by gas that has leaked from a combustion chamber of the internal combustion engine into a crankcase into an intake system of the internal combustion engine; a ventilation case provided midway through the blow-by gas passage; a PCV (Positive Crankcase Ventilation) valve provided in the blow-by gas passage and attached to the ventilation case, the PCV valve being configured to adjust the amount of blow-by gas flowing through the blow-by gas passage; a plate covering the PCV valve and attached to the ventilation case; and a cover covering the plate and in contact with a portion of the plate. [Effects of the Invention]

[0006] According to the above configuration, it is possible to suppress vibration of the plate when the internal combustion engine is in operation, thereby suppressing noise. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an internal combustion engine according to one embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing a plurality of members attached to a ventilation case of the internal combustion engine shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view showing a portion of a ventilation case provided in the internal combustion engine shown in FIG. 1 where a PCV valve is fixed. DETAILED DESCRIPTION OF THE INVENTION

[0008] An internal combustion engine according to an embodiment will now be described with reference to the drawings. <Configuration of internal combustion engine 100> As shown in Fig. 1, the internal combustion engine 100 has a cylinder block 16. The internal combustion engine 100 has a cylinder head 18 attached to the upper end of the cylinder block 16. The internal combustion engine 100 has a crankcase 12 attached to the lower end of the cylinder block 16. In addition, the upper part of the cylinder head 18 is covered by a ventilation case 22.

[0009] When fuel is burned in the combustion chamber 10 of the internal combustion engine 100, blow-by gas leaks from the combustion chamber 10 of the internal combustion engine 100 into the crankcase 12. The internal combustion engine 100 is equipped with a blow-by gas reduction device for causing the blow-by gas that has leaked into the crankcase 12 to flow into the intake system 14 of the internal combustion engine 100. FIG. 1 shows an intake passage 14a that is part of the intake system 14.

[0010] The blow-by gas returning device has a blow-by gas passage 20 for causing the blow-by gas to flow into the intake system 14 of the internal combustion engine 100. The blow-by gas returning device is equipped with a PCV (Positive Crankcase Ventilation) valve 24 for adjusting the amount of blow-by gas flowing through the blow-by gas passage 20. The PCV valve 24 is provided in the blow-by gas passage 20 and attached to the ventilation case 22.

[0011] The blow-by gas passage 20 communicates with the crankcase 12. The blow-by gas passage 20 extends through the cylinder block 16 and the cylinder head 18. The interior of the ventilation case 22 forms part of the blow-by gas passage 20. As described above, the PCV valve 24 is attached to the ventilation case 22. The hose 21 connects the PCV valve 24 to the intake passage 14a. The interior of the hose 21 forms part of the blow-by gas passage 20. In this way, the blow-by gas passage 20 communicates with the intake passage 14a.

[0012] In this way, the ventilation case 22 is provided in the middle of the blow-by gas passage 20. The PCV valve 24 is provided in the middle of the blow-by gas passage 20. As described above, the PCV valve 24 adjusts the amount of blow-by gas flowing through the blow-by gas passage 20. This changes the flow rate of blow-by gas flowing from the crankcase 12 to the intake passage 14a.

[0013] The internal combustion engine 100 includes a plate 26 that covers the PCV valve 24 and is attached to the ventilation case 22. The internal combustion engine 100 includes a cover 28 that covers the plate 26 and is in contact with a portion of the plate 26. The cover 28 is a urethane cover 28 made of urethane, and surrounds the PCV valve 24.

[0014] <Method of attaching the PCV valve 24, plate 26, and cover 28 to the ventilation case 22 in this order> 2, a method for attaching the PCV valve 24, plate 26, and cover 28 to the ventilation case 22 in this order will be described. The ventilation case 22 has an attachment portion 22a, which is a protruding portion of the ventilation case 22. The attachment portion 22a has an attachment hole 22b.

[0015] First, in the first stage, the PCV valve 24 is attached to the ventilation case 22 with the entire first portion 24a of the PCV valve 24 inserted into the mounting hole 22b of the mounting portion 22a. Here, the second portion 24b of the PCV valve 24, which is continuous with the first portion 24a, is located outside the mounting hole 22b. The diameter of the PCV valve 24 is largest at the second portion 24b. Furthermore, the second portion 24b of the PCV valve 24 completely covers the mounting hole 22b. Furthermore, the PCV valve 24 has a third portion 24c that extends from the second portion 24b in a direction away from the mounting hole 22b. The third portion 24c is the portion to which the hose 21 is connected.

[0016] Next, in the second stage, the plate 26 is attached to the ventilation case 22 so as to cover the PCV valve 24. More specifically, first, the third portion 24c of the PCV valve 24 is passed through the hole of the bent portion 26b described later. Next, the two cylindrical portions 22c of the attachment portion 22a are passed through the two holes of the cantilever portion 26a of the plate 26. Next, the two cylindrical portions 22c are deformed by heating. Thereby, the plate 26 is welded to the attachment portion 22a. Note that FIG. 3 shows the deformed cylindrical portion 22c'.

[0017] The plate 26 has a cantilever portion 26a partially fixed to the attachment portion 22a of the ventilation case 22 and a bent portion 26b bent and extending from the cantilever portion 26a. The cantilever portion 26a is supported by two protrusions 22d of the attachment portion 22a. The bent portion 26b partially covers the second portion 24b of the PCV valve 24 in the axial direction of the attachment hole 22b. The bent portion 26b does not cover the third portion 24c of the PCV valve 24 in the axial direction of the attachment hole 22b. The plate 26 further has a first side portion 26c and a second side portion 26d extending from the bent portion 26b so as to approach the PCV valve 24 in the axial direction of the attachment hole 22b.

[0018] Finally, in the third stage, the cover 28 is attached to the ventilation case 22 so as to cover the plate 26. <PCV Valve 24 and Its Surroundings> Referring to FIG. 3, the PCV valve 24 and its surroundings will be described. The cover 28 is in contact with the entire cantilever portion 26a. The second portion 24b of the PCV valve 24 and the bent portion 26b in the axial direction of the attachment hole 22b are separated by a distance D. The second portion 24b has an opposing surface facing the bent portion 26b and orthogonal to the axial direction of the attachment hole 22b. The distance D is the distance between the opposing surface of the second portion 24b and the bent portion 26b in the axial direction of the attachment hole 22b. The distance D is shorter than the length L of the first portion 24a of the PCV valve 24 in the axial direction of the attachment hole 22b.

[0019] <Actions and Effects of This Embodiment> (1) The internal combustion engine 100 is provided with a blow-by gas passage 20 for allowing blow-by gas that has leaked from the combustion chamber 10 of the internal combustion engine 100 to flow into the crankcase 12, to the intake system 14 of the internal combustion engine 100. The internal combustion engine 100 is further provided with a ventilation case 22 provided midway through the blow-by gas passage 20. The internal combustion engine 100 is further provided with a PCV (Positive Crankcase Ventilation) valve 24 provided in the blow-by gas passage 20 and attached to the ventilation case 22. The PCV valve 24 is configured to adjust the amount of blow-by gas flowing through the blow-by gas passage 20. The internal combustion engine 100 is further provided with a plate 26 that covers the PCV valve 24 and is attached to the ventilation case 22. The internal combustion engine 100 is further provided with a cover 28 that covers the plate 26 and is in contact with a portion of the plate 26.

[0020] The cover 28 is in contact with a portion of the plate 26. This makes it possible to suppress vibration of the plate 26 when the internal combustion engine 100 is in operation, thereby suppressing noise.

[0021] Furthermore, the cover 28 comes into contact with a portion of the plate 26, thereby increasing the resonance frequency of the plate 26. The resonance frequency is moved away from the forced vibration frequency, thereby suppressing the vibration of the plate 26.

[0022] (2) The ventilation case 22 has a mounting portion 22a, which is a protruding portion of the ventilation case 22. The PCV valve 24 is mounted to the ventilation case 22 in the following manner. The entire first portion 24a of the PCV valve 24 is inserted into the mounting hole 22b of the mounting portion 22a. Furthermore, a second portion 24b of the PCV valve 24, which is continuous with the first portion 24a, is located outside the mounting hole 22b. Furthermore, the second portion 24b of the PCV valve 24 completely covers the mounting hole 22b. The PCV valve 24 has a third portion 24c that extends from the second portion 24b in a direction away from the mounting hole 22b. The PCV valve 24 has the largest diameter at the second portion 24b.

[0023] The plate 26 has a cantilever portion 26a that is partially fixed to the mounting portion 22a of the ventilation case 22, and a bent portion 26b that bends and extends from the cantilever portion 26a. The bent portion 26b partially covers the second portion 24b of the PCV valve 24 in the axial direction of the mounting hole 22b. The bent portion 26b does not cover the third portion 24c of the PCV valve 24 in the axial direction of the mounting hole 22b. The distance D between the second portion 24b of the PCV valve 24 and the bent portion 26b in the axial direction of the mounting hole 22b is shorter than the length L of the first portion 24a of the PCV valve 24 in the axial direction of the mounting hole 22b.

[0024] In the above configuration, the bent portion 26b partially covers the second portion 24b of the PCV valve 24 in the axial direction of the mounting hole 22b. The distance D between the second portion 24b of the PCV valve 24 and the bent portion 26b in the axial direction of the mounting hole 22b is shorter than the length L of the first portion 24a of the PCV valve 24 in the axial direction of the mounting hole 22b. Therefore, the bent portion 26b prevents the first portion 24a of the PCV valve 24 from being removed from the mounting hole 22b. In other words, it is difficult to remove the first portion 24a of the PCV valve 24 from the mounting hole 22b unless the plate 26 is removed from the ventilation case 22. This prevents the PCV valve 24 from being removed from the ventilation case 22.

[0025] (3) The cover 28 is in contact with the entire cantilever portion 26a. Since the cover 28 is in contact with the entire cantilever portion 26a, vibration of the plate 26 can be more easily suppressed compared to a configuration in which the cover 28 is in contact with only a portion of the cantilever portion 26a.

[0026] (4) The plate 26 is welded to the mounting portion 22a. According to the above configuration, the plate 26 is difficult to remove. (5) The cover 28 is a urethane cover 28 formed from urethane and surrounds the PCV valve 24.

[0027] In the above configuration, the cover 28 enhances the heat retention of the PCV valve 24. <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0028] In the above embodiment, the upper part of the cylinder head 18 is covered by the ventilation case 22. However, this is merely an example. For example, the ventilation case 22 may be attached to the cylinder block 16.

[0029] In the above embodiment, the plate 26 has the first side portion 26c and the second side portion 26d. At least one of the first side portion 26c and the second side portion 26d may be omitted. In the above embodiment, the plate 26 is welded to the mounting portion 22a. Alternatively, the plate 26 may be fixed to the mounting portion 22a by caulking.

[0030] In the above embodiment, as described above, the distance D is shorter than the length L. However, the distance D may be equal to or greater than the length L. In the above embodiment, the cover 28 is in contact with the entire cantilever portion 26a. However, the cover 28 may be in contact with only a portion of the cantilever portion 26a.

[0031] In the above embodiment, the cover 28 is a urethane cover 28 made of urethane. However, this is merely an example. For example, the cover 28 may be made of a resin other than urethane. [Explanation of symbols]

[0032] 10... combustion chamber, 12... crankcase, 14... intake system, 20... blow-by gas passage, 22... ventilation case, 22a... mounting portion, 22b... mounting hole, 24... PCV valve, 24a... first portion, 24b... second portion, 24c... third portion, 26... plate, 26a... cantilever portion, 26b... bent portion, 28... cover (urethane cover), 100... internal combustion engine

Claims

1. An internal combustion engine, a blow-by gas passage for allowing blow-by gas leaking from a combustion chamber of the internal combustion engine to a crankcase to flow into an intake system of the internal combustion engine; a ventilation case provided midway through the blow-by gas passage; a PCV (Positive Crankcase Ventilation) valve provided in the blow-by gas passage and attached to the ventilation case, the PCV valve configured to adjust the amount of blow-by gas flowing through the blow-by gas passage; a plate covering the PCV valve and attached to the ventilation case; a cover covering the plate and in contact with a portion of the plate; Internal combustion engine.

2. the ventilation case has a mounting portion that is a protruding portion of the ventilation case, the PCV valve is mounted to the ventilation case in a state in which a first portion of the PCV valve is entirely inserted into a mounting hole of the mounting portion, a second portion of the PCV valve that is continuous with the first portion is located outside the mounting hole, and the second portion of the PCV valve entirely covers the mounting hole; the PCV valve has a third portion extending from the second portion in a direction away from the mounting hole, and the PCV valve has a largest diameter at the second portion; the plate has a cantilever portion partially fixed to the mounting portion of the ventilation case and a bent portion bent and extending from the cantilever portion, the bent portion partially covering the second portion of the PCV valve in the axial direction of the mounting hole, and the bent portion does not cover the third portion of the PCV valve in the axial direction of the mounting hole, a distance between the second portion of the PCV valve and the bent portion in the axial direction of the mounting hole is shorter than a length of the first portion of the PCV valve in the axial direction of the mounting hole; 2. The internal combustion engine according to claim 1.

3. the ventilation case has a mounting portion that is a protruding portion of the ventilation case, the PCV valve is mounted to the ventilation case in a state in which a first portion of the PCV valve is entirely inserted into a mounting hole of the mounting portion, a second portion of the PCV valve that is continuous with the first portion is located outside the mounting hole, and the second portion of the PCV valve entirely covers the mounting hole; the plate has a cantilever portion partially fixed to the mounting portion of the ventilation case and a bent portion bent and extending from the cantilever portion, the bent portion partially covering the second portion of the PCV valve in the axial direction of the mounting hole, The cover is in contact with the entire cantilever portion.

2. The internal combustion engine according to claim 1.

4. The plate is welded to the mounting portion.

3. The internal combustion engine according to claim 2.

5. The cover is a urethane cover formed from urethane and surrounds the PCV valve. An internal combustion engine according to any one of claims 1 to 4.

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