Oil separator structure of a blow-by gas recirculation system and vehicle

Abstract

This invention provides an oil separator structure and vehicle for a blow-by recirculation system, which can more effectively suppress the backflow of oil from the oil separation chamber to the intake side. In the oil separator structure (A) of the blow-by recirculation system disclosed herein, the baffle (10) includes an oil drain hole (12) and a concave oil storage part (11). The oil storage part (11) stores the oil separated from the blow-by in the oil separation chambers (Ax, Ay). The oil drain hole (12) allows the oil stored in the oil storage part (11) to return to the cam chamber. An upper cover plate (13U) covering the oil storage part (11) from above is disposed on the upper surface of the baffle (10), and a lower cover plate (13D) covering the oil drain hole (12) from below is disposed on the lower surface of the baffle (10).

Description

Technical Field

[0001] This disclosure relates to the structure of an oil separator in a blow-by recirculation system and to a vehicle thereof. Background Technology

[0002] Previously, blow-by gas recirculation systems were known to return blow-by gas generated on the crankcase side of an internal combustion engine to the intake side. In such blow-by gas recirculation systems, an oil separator structure is typically provided to separate and remove oil components such as lubricating oil contained in the blow-by gas before it flows back to the intake side.

[0003] As a structure of such oil separator, there is a known structure in which a baffle covers the upper part of the cam chamber inside the cylinder head cover, and an oil separation chamber (also called a ventilation chamber or PCV chamber) is formed between the inner wall of the cylinder head cover and the baffle to collect blow-by gas from the upper space of the cylinder head, and the oil separated in the oil separation chamber is returned to the cylinder head side (see, for example, Patent Document 1).

[0004] In a blow-by gas recirculation system with this type of oil separator structure, by connecting the downstream end of the oil separator chamber, for example, to the intake side of the internal combustion engine, a negative pressure is introduced on the downstream side of the oil separator chamber. This negative pressure causes blow-by gas to be collected from the space above the cylinder head into the oil separator chamber. As the collected blow-by gas is guided from the upstream side to the downstream side of the oil separator chamber, it collides with a guide wall located within the oil separator chamber, causing oil droplets in the gas to fall onto the wall of a baffle and be separated. Then, the blow-by gas, separated and de-oiled in this manner, flows back to the intake side of the internal combustion engine.

[0005] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2005-120855. Summary of the Invention

[0006] The problem the invention aims to solve However, such oil separator structures typically employ the following configuration: an oil storage section is formed on the upper surface of the baffle, and an oil drain hole is formed within the oil storage section to allow the stored oil to return to the cam chamber. Through this oil drain hole, the oil separated in the oil separator chamber returns to the cylinder head side (i.e., the cam chamber).

[0007] However, the inventors of this application discovered through in-depth research that in the conventional oil separator structure, the blow-by gas in the space above the cylinder head may not pass through the oil separation mechanism in the oil separation chamber (i.e., the separation passage formed by the guide wall), but instead be directly blown into the oil storage section through the oil drain hole.

[0008] When the influx of such blow-by gas becomes significant, oil accumulated in the oil reservoir may be blown up in the oil separator chamber, and this oil may flow back to the intake side in large quantities along with the blow-by gas. In addition, when no oil accumulates in the oil reservoir, oil mist may be blown into the oil separator chamber along with the blow-by gas through the oil drain hole.

[0009] If the above conditions occur, it will worsen engine exhaust emissions. In addition, oil consumption (LOC) will also increase.

[0010] The present invention was made in view of the above-mentioned problems. That is, the present invention aims to provide an oil separator structure and vehicle for a blow-by recirculation system, which can more effectively suppress the backflow of oil from the oil separator chamber to the intake side.

[0011] Solution to the problem The main content of this invention, which solves the above problems, is an oil separator structure, specifically an oil separator structure for a blow-by recirculation system. In this oil separator structure, a baffle covers the upper part of the cam chamber inside the cylinder head cover of an internal combustion engine, forming an oil separation chamber that collects blow-by gas from the upper space inside the cylinder head and separates the oil contained in the blow-by gas. The baffle includes an oil drain hole and a concave oil storage section, the oil storage section storing oil separated from the blow-by gas in the oil separation chamber, and the oil drain hole allowing the oil stored in the oil storage section to return to the cam chamber. An upper cover plate is provided on the upper surface of the baffle to cover the oil storage section from above. A lower cover plate is provided on the lower surface of the baffle to cover the oil drain hole from below.

[0012] In addition, on the other hand, there is a vehicle that has the aforementioned oil separator structure.

[0013] Invention Effects The oil separator structure of the blow-by recirculation system according to the present invention can more effectively suppress the backflow of oil from the oil separation chamber to the intake side. Attached Figure Description

[0014] Figure 1 This is a three-dimensional view of the cylinder head cover from above.

[0015] Figure 2 This is a three-dimensional view of the baffle from the back side of the cylinder head cover.

[0016] Figure 3 This is a top view of the baffle from the back side of the cylinder head cover.

[0017] Figure 4 It is a magnified three-dimensional view of the oil return structure formed on the baffle.

[0018] Figure 5It is an enlarged longitudinal sectional view of the oil return structure formed on the baffle.

[0019] Figure 6 It is an enlarged longitudinal sectional view of the oil return structure formed on the baffle.

[0020] Explanation of reference numerals in the attached figures A. Oil separator structure Ax PCV chamber (oil separation chamber) Ay Ventilation Chamber (Oil Separation Chamber) 1. Cylinder head cover 1a Top 1b Sidewall portion 1c Flange portion 10 baffles 10. Oil Storage Section 10a base plate 10b Enclosure 10c guide wall 10Q oil return structure 11 Oil Storage Section 12 Oil drain holes 13D lower cover plate 13Da Second Shielding Section 13Db Second opening 13U upper cover panel 13Ua First Shielding Section 13Ub First opening 100 Cylinder Head 100x Cam Chamber 101 Cam Ta gas inlet Tb is the gas outlet. Detailed Implementation

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, components having substantially the same function are labeled with the same reference numerals, and repeated descriptions are omitted.

[0022] The following describes the oil separator structure (hereinafter referred to as "oil separator structure A") of a blow-by recirculation system according to one embodiment of the present invention. Furthermore, the oil separator structure A of this embodiment can be applied to any internal combustion engine (e.g., a diesel engine, gasoline engine, natural gas engine, hydrogen engine, ethanol engine, or ammonia-fueled engine) and mounted on a vehicle together with such an internal combustion engine.

[0023] Figure 1 This is a three-dimensional view of the cylinder head cover 1 viewed from above. Figure 2This is a perspective view of the baffle 10 viewed from the back side of the cylinder head cover 1. Figure 3 This is a top view of the baffle 10 as seen from the rear side of the cylinder head cover 1. Additionally, Figure 3 The arrows in the diagram show the flow path of the gas leakage in the oil separation chambers Ax and Ay.

[0024] Figure 4 This is a magnified three-dimensional view of the oil return structure 10Q formed on the baffle 10. Figure 5 and Figure 6 This is an enlarged longitudinal sectional view of the oil return structure 10Q formed on the baffle 10. Additionally, Figure 5 The image depicts the state in which the oil separation chamber Ax is formed by the baffle 10 in the space above the cylinder head 100 (i.e., the cam chamber 100x).

[0025] First, refer to Figures 1-3 The overall structure of oil separator structure A will be described.

[0026] The oil separator structure A has a baffle 10 covering the upper part of the cam chamber 100x inside the cylinder head cover 1. Oil separation chambers Ax and Ay are formed between the inner wall of the cylinder head cover 1 and the baffle 10 for collecting blow-by gas from the upper space of the cylinder head 100. Furthermore, this structure allows the oil separated in the oil separation chambers Ax and Ay to return to the cam chamber 100x side.

[0027] Furthermore, in the oil separator structure A of this embodiment, the oil separation chambers Ax and Ay are formed as a PCV (Positive Crankcase Ventilation) chamber Ax, which is connected to the downstream side passage of the intake manifold of the internal combustion engine, and a ventilation chamber Ay, which is connected to the upstream side passage of the intake manifold of the internal combustion engine. Within the baffle 10, the PCV chamber Ax and the ventilation chamber Ay are formed as independent spaces separated by the sidewall (i.e., there is no gas exchange between them).

[0028] The PCV chamber Ax primarily collects blow-by gases from the space above the cylinder head during low-load operation of the internal combustion engine and redirects these gases to the downstream passage of the intake manifold (e.g., downstream of the turbocharger). The snorkel chamber Ay primarily collects blow-by gases from the space above the cylinder head during high-load operation of the internal combustion engine and redirects these gases to the upstream passage of the intake manifold (e.g., upstream of the turbocharger).

[0029] The structures of PCV chamber Ax and ventilation chamber Ay are roughly the same. Therefore, for ease of explanation, only the structure of PCV chamber Ax side will be described below.

[0030] In addition, blow-by recirculation systems with a PCV chamber and a ventilation chamber as oil separation chambers are particularly suitable for use in internal combustion engines employing the Otto cycle (e.g., gasoline engines or natural gas engines).

[0031] The cylinder head cover 1 includes a top 1a that is generally rectangular when viewed from above, sidewall portions 1b extending downwards from the periphery of the top 1a, and a flange portion 1c that extends generally horizontally outwards from the lower end of the sidewall portions 1b. The flange portion 1c is bolted to the cylinder head 100 after a sealing member is installed into a groove on the lower surface of the flange portion 1c (see [link to documentation]). Figure 5 The cylinder head cover 1 is installed on the cylinder head 100 by attaching it to the upper side of the cylinder head cover 1.

[0032] A baffle 10 is installed on the rear side of the cylinder head cover 1. More specifically, the baffle 10 has a base plate 10a and a surrounding wall 10b erected from the edge of the base plate 10a. The upper end of the surrounding wall 10b is installed on the top 1a of the cylinder head cover 1 by welding or the like. As a result, a tunnel-shaped oil separation chamber Ax is formed between the baffle 10 and the inner wall of the cylinder head cover 1.

[0033] A gas inlet Ta is formed on the base plate 10a of the baffle 10, opening into the space above the cylinder head 100. Thus, blow-by gas in the space above the cylinder head 100 flows into the oil separator Ax through the gas inlet Ta.

[0034] A gas outlet Tb is formed on the top 1a of the cylinder head cover 1. Thus, blow-by gas flowing into the oil separator Ax returns to the intake manifold of the internal combustion engine via the gas outlet Tb. Additionally, a PCV (Positive Crankcase Ventilation) valve (see [reference]) is installed at the gas outlet Tb. Figure 1 The blow-by gas flowing into the oil separator Ax flows back to the intake manifold of the internal combustion engine via the PCV valve.

[0035] Furthermore, the baffle 10 has a guide wall 10c erected from the bottom plate 10a, thereby forming a guide path for cross-flow gas within the oil separation chamber Ax. The guide wall 10c is arranged within the oil separation chamber Ax in such a way that cross-flow gas flowing in from the gas inlet Ta is guided along a meandering flow path to the gas outlet Tb.

[0036] Thus, the oil separator Ax forms a closed space between the gas inlet Ta and the gas outlet Tb. Furthermore, the oil separator Ax is connected to the intake side of the internal combustion engine via the gas outlet Tb, thereby introducing negative pressure into the oil separator Ax and using this negative pressure to collect blow-by gas from the space above the cylinder head 100 into the oil separator Ax.

[0037] Therefore, the blow-by gas is collected from the space above the cylinder head 100 into the oil separator Ax, and guided by the guide wall 10c from the gas inlet Ta to the gas outlet Tb of the oil separator Ax. During this process, the oil in the blow-by gas collides with the guide wall 10c located in the oil separator Ax and drips onto the bottom plate 10a of the baffle 10. After the blow-by gas has been separated and the oil removed in this way, it flows back to the intake side of the internal combustion engine through the gas outlet Tb (i.e., the PCV valve).

[0038] The baffle 10 is configured such that when the internal combustion engine is mounted on a vehicle or similar vehicle (hereinafter referred to as "in use"), the base plate 10a of the baffle 10 is as follows: Figure 2 , Figure 3 As indicated by arrow L, the baffle 10 is tilted downwards at a predetermined angle. Because the bottom plate 10a of the baffle 10 is tilted in this way, the oil that collides with the guide wall 10c and drips onto the bottom plate 10a (i.e., the oil separated from the blow-by gas) flows along the bottom plate 10a toward the closed end of the lower side of the baffle 10.

[0039] At the closed end of the lower side of the baffle 10, an oil return structure 10Q is formed to return the oil separated from the blow-by gas in the oil separation chamber Ax to the cam chamber 100x side.

[0040] Next, refer to Figures 4 to 6 The structure of the 10Q oil return structure is described in detail.

[0041] The oil return structure 10Q consists of an oil storage section 11, an oil drain hole 12, an upper cover plate 13U, and a lower cover plate 13D. Additionally, in Figure 6 The flow of cross-flowing gas is depicted by the arrow BG.

[0042] The oil storage section 11 is a concave groove formed on the upper surface of the bottom plate 10a of the baffle 10, used to store oil separated from blow-by gas in the oil separation chamber Ax. Furthermore, as described above, the bottom plate 10a of the baffle 10 is arranged to tilt downwards at a predetermined angle when the internal combustion engine is in operation. Therefore, the oil separated from blow-by gas in the oil separation chamber Ax flows along the bottom plate 10a to the closed end on the lower side of the baffle 10 and accumulates in the oil storage section 11.

[0043] The oil drain hole 12 is a hole provided inside the oil storage section 11, which penetrates the bottom plate 10a of the baffle 10 in a vertical direction, and is used to return the oil accumulated in the oil storage section 11 to the cam chamber 100x.

[0044] Furthermore, preferably, the oil drain hole 12 is formed in a circular shape with a diameter greater than or equal to 0.5 mm and less than 2.5 mm. This allows an oil film to form in the oil drain hole 12 due to the surface tension of the oil, thereby maintaining the oil storage section 11 in an oil-storing state for a longer period. By keeping the oil storage section 11 in an oil-storing state, it is possible to prevent oil mist and cross-venting gas from being blown into the oil separation chamber Ax through the oil drain hole 12.

[0045] The upper cover plate 13U is a plate component that is disposed on the upper surface of the baffle 10 in such a way as to cover the oil storage section 11 from above.

[0046] More specifically, the upper cover plate 13U forms a first shielding portion 13Ua on the inner side of the oil separation chamber Ax, and a first opening portion 13Ub on the outer side of the oil separation chamber Ax (see...). Figure 6 The first shielding portion 13Ua provides shielding to prevent cross-flow gas flowing in the oil separation chamber Ax from blowing into the oil storage section 11. Furthermore, the first opening portion 13Ub is a region that serves as a passage for oil separated from cross-flow gas in the oil separation chamber Ax to flow into the oil storage section 11.

[0047] The upper cover plate 13U serves to prevent the oil accumulated in the oil reservoir 11 from being carried away by the cross-flowing gas flowing in the oil separation chamber Ax. In particular, when the negative pressure generated in the oil separation chamber Ax is large, cross-flowing gas may rise from the oil drain hole 12 side, causing the oil accumulated in the oil reservoir 11 to be blown up along with the cross-flowing gas. Since the upper cover plate 13U is arranged to cover the oil drain hole 12 from above, even in this case, the upper cover plate 13U can prevent the oil accumulated in the oil reservoir 11 from being blown upwards.

[0048] Furthermore, when the flow of cross-flowing gas in the oil separation chamber Ax is strong, the oil accumulated in the oil storage section 11 may be vaporized by the high-temperature cross-flowing gas and carried away directly. The first shielding part 13Ua of the upper cover plate 13U can also suppress this situation.

[0049] The lower cover plate 13D is a plate component disposed on the lower surface of the baffle 10 in such a way as to cover the oil drain hole 12 from below.

[0050] More specifically, the lower cover plate 13D forms a second shielding portion 13Da on the outer side of the cam chamber 100x, and a second opening portion 13Db on the inner side of the cam chamber 100x (see...). Figure 6 The second shielding portion 13Da provides shielding to prevent blow-by gas flowing in the cylinder head 100 from being blown toward the oil drain hole 12. The second opening portion 13Db is an area that serves as a passage for oil dripping from the oil drain hole 12 to return to the cam chamber 100x.

[0051] The lower cover plate 13D suppresses the flow of oil mist rising from the upper space of the cylinder head 100 towards the drain hole 12 along with blow-by gas into the oil separator chamber Ax when there is no oil stored in the oil reservoir 11. Generally, based on the relationship with the rotation direction of the cam 101 in the cam chamber 100x, the oil mist rising from the upper space of the cylinder head 100 towards the drain hole 12 will reach the drain hole 12 from the outside of the cam chamber 100x along with blow-by gas (see...). Figure 5 , Figure 6 The second shielding part 13Da of the lower cover plate 13D will shield the blow-out air from the outside of the cam chamber 100x toward the oil drain hole 12, thereby more effectively suppressing the entry of oil mist into the oil drain hole 12.

[0052] In addition, the oil dripping from the drain hole 12 returns to the cam chamber 100x through the second opening 13Db.

[0053] [Effect] In the above embodiments, an oil separator structure A is disclosed, which is an oil separator structure A for a blow-by gas recirculation system. A baffle 10 covers the upper part of the cam chamber inside the cylinder head cover 1 of the internal combustion engine, forming oil separation chambers Ax and Ay that collect blow-by gas from the upper space inside the cylinder head and separate the oil contained in the blow-by gas. The baffle 10 includes an oil drain hole 12 and a concave oil storage section 11. The oil storage section 11 stores the oil separated from the blow-by gas in the oil separation chambers Ax and Ay. The oil drain hole 12 allows the oil stored in the oil storage section 11 to return to the cam chamber. An upper cover plate 13U is provided on the upper surface of the baffle 10 to cover the oil storage section 11 from above. A lower cover plate 13D is provided on the lower surface of the baffle 10, which covers the oil drain hole 12 from below.

[0054] According to the oil separator structure A of this embodiment, the backflow of oil from the oil separation chambers Ax and Ay to the intake side can be effectively suppressed. This improves exhaust emissions from the engine and reduces oil consumption (LOC).

[0055] (Other implementation methods) The present invention is not limited to the above-described embodiments and can be applied to various modified forms.

[0056] For example, in the above embodiment, it was described that both the PCV chamber Ax and the ventilation chamber Ay have the same oil return structure 10Q. However, there are also cases where the ventilation chamber Ay does not generate the same engine negative pressure as the PCV chamber Ax. From this perspective, for example, it is also possible to configure a structure in which only the upper cover plate 13U and the lower cover plate 13D are provided in the PCV chamber Ax.

[0057] Furthermore, the above embodiments disclose an oil separator structure A having both a PCV chamber Ax and a ventilation chamber Ay. However, the structure of this oil separator structure A depends on the structure of the blow-by recirculation system. When implementing the oil separator structure of the present invention, only one of the PCV chamber Ax and the ventilation chamber Ay may be provided within the baffle 10. For example, in the case of a diesel engine, as a blow-by recirculation system, a structure is sometimes adopted in which only the ventilation chamber Ay is provided without the PCV chamber Ax.

[0058] The specific examples of the present invention have been described in detail above, but these are merely illustrative and not intended to limit the scope of the claims. The technology described in the claims includes various modifications and alterations to the specific examples illustrated above.

[0059] Industrial applicability The oil separator structure of the blow-by recirculation system according to the present invention can more effectively suppress the backflow of oil from the oil separation chamber to the intake side.

Claims

1. An oil separator structure, which is an oil separator structure for a blow-by gas recirculation system, wherein a baffle covers the upper part of the cam chamber inside the cylinder head cover of an internal combustion engine, forming an oil separation chamber for collecting blow-by gas from the upper space inside the cylinder head and separating the oil contained in the blow-by gas, wherein... The baffle includes an oil drain hole and a concave oil storage section, the oil storage section storing oil separated from the blow-by gas in the oil separation chamber, and the oil drain hole allowing the oil stored in the oil storage section to return to the cam chamber. An upper cover plate is provided on the upper surface of the baffle to cover the oil storage section from above. A lower cover plate is provided on the lower surface of the baffle to cover the oil drain hole from below.

2. The oil separator structure as described in claim 1, wherein, The upper cover plate forms a first shielding portion on the inner side of the oil separation chamber and a first opening portion on the outer side of the oil separation chamber.

3. The oil separator structure as described in claim 1, wherein, The lower cover plate forms a second shielding portion on the outside of the cam chamber and a second opening portion on the inside of the cam chamber.

4. The oil separator structure as described in claim 1, wherein, The oil storage unit is located at the lower closed end of the baffle when the internal combustion engine is in use.

5. The oil separator structure as described in claim 1, wherein, The drain hole is circular in shape with a diameter greater than or equal to 0.5 mm and less than 2.5 mm.

6. A vehicle, wherein, It has the oil separator structure as described in claim 1.

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