JP3176727U - Oil return passage structure for internal combustion engine - Google Patents

Abstract

An oil return passage structure for an internal combustion engine in which blow-by gas, carbon-containing substances contained in oil, and the like are difficult to adhere to an inner wall of an oil return hole is provided.
A valve operating chamber (5) having camshafts (12a, 12b) for controlling an intake side valve operating mechanism (11a) and an exhaust side valve operating mechanism (11b), a crankcase (6) having a crankshaft (15) and an oil pan (3), The valve chamber 5 and the crankcase 6 are connected to each other, and oil return holes 7a and 7b are provided to return the oil 10 supplied from the oil pan 3 to the valve operating chamber 5 to the oil pan 3. The oil return holes 7a and 7b The inner wall is formed of fluororesins 16a and 16b such as polytetrafluoroethylene.
[Selection] Figure 1

Description

  In the present invention, mainly in an automobile engine, oil (lubricating oil) supplied from an oil pan at the bottom of a crankcase to a moving mechanism, in particular, a valve chamber that houses a camshaft, is transferred to an oil pan through an oil return hole. The present invention relates to an oil return passage structure for a returning internal combustion engine.

An automobile engine has movable mechanism parts such as a crankshaft and a camshaft, and an oil pump is used so that the movable mechanism parts move smoothly and the temperature of the movable mechanism parts does not rise. The oil (lubricating oil) stored in the oil pan at the bottom of the crankcase is circulated inside the engine. The oil is finally returned to the oil pan through the oil return hole from the valve operating chamber that houses the camshaft.
On the other hand, unburned fuel gas compressed in the cylinder leaks into the crankcase from the gap between the piston and the cylinder inner wall together with steam, combustion gas, oil mist, and the like. Leaked unburned fuel gas or the like (blow-by gas) oxidizes and degrades the oil, so it is necessary to discharge it from the crankcase as soon as possible. In this case, harmful blow-by gas is generally returned directly to the intake system without being directly discharged to the outside to be reburned. For this reason, blow-by gas is sent from the crankcase to the valve operating chamber through the oil return hole, and is further returned from the valve operating chamber to the intake system.
The structure of such an engine is described in Patent Document 1 below.
JP 2005-54702 A

By the way, since blow-by gas contains a lot of oil, its inclusions adhere to the inner wall of the oil return hole, and carbon-containing substances adhere. Similarly, the oil circulated in the engine also adheres to the inner wall of the oil return hole, and the carbon-containing material adheres. For this reason, the passage of blow-by gas and oil gradually deteriorates in the oil return hole, so that the oil tends to deteriorate or the performance of the engine tends to deteriorate.
The present invention was created in view of the above-described problems of the conventional example, and an oil return passage structure for an internal combustion engine in which blow-by gas, carbon-containing materials contained in oil, and the like are difficult to adhere to the inner wall of the oil return hole. Is to provide.

In order to solve the above problems, a first device relates to an oil return passage structure of an internal combustion engine, and includes a valve chamber including a camshaft for controlling an intake side valve mechanism and an exhaust side valve mechanism, a crankshaft, A crankcase provided with an oil pan; and an oil return hole that connects the valve chamber and the crankcase, and returns oil supplied from the oil pan to the valve chamber to the oil pan. The inner wall of the oil return hole is made of polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer. Polymer (ETFE), polyvinylidene fluoride (PVDF) polychlorotrifluoroethylene ( CTFE), and characterized in that it is formed at a selected fluorocarbon resin among the polyphenylene sulfide (PPS),
The second device relates to the oil return passage structure of the internal combustion engine of the first device, wherein the valve chamber is formed, a cylinder head in which an upper portion of the oil return hole is formed, and the crankcase are formed. It has a cylinder block formed with a lower portion of the oil return hole,
The third invention relates to the oil return passage structure of the internal combustion engine of the first invention, characterized in that the entire inner wall of the oil return hole is covered with the fluororesin.

In the present invention, the inner wall of the oil return hole is made of polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetra It is made of a fluororesin selected from fluoroethylene / ethylene copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and polyphenylene sulfide (PPS). Since these fluororesins are excellent in heat resistance, non-adhesiveness and low friction, if the inner wall of the oil return hole in the internal combustion engine that becomes high temperature is formed of this fluororesin, the carbon content contained in blow-by gas and oil is contained. It becomes difficult for objects to stick to the inner wall of the oil return hole.
Thereby, since the state where the blow-by gas or the oil in the oil return hole is good can be maintained for a long time, the deterioration of the oil can be prevented and the performance of the engine can be maintained for a long time.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the structure of an engine (internal combustion engine) having an oil return passage structure according to an embodiment of the present invention.
In the figure, reference numeral 1 is a cylinder block, 2 is a cylinder head provided at the top of the cylinder block 1, 17 is a cylinder head cover attached to the upper surface of the cylinder head 2, and 3 is an oil provided at the bottom of the cylinder block 1. 10 is an oil pan storing 10.
Reference numeral 4 denotes a cylinder (combustion chamber) formed in the cylinder block 1, in which gasoline vapor is exploded (combusted) to move the piston 14. As the piston 14 moves, the crankshaft 15 connected to the piston 14 rotates.
Reference numeral 5 denotes a valve chamber that houses camshafts 12a and 12b that control the intake side valve mechanism 11a and the exhaust side valve mechanism 11b. The intake side valve mechanism 11a opens and closes the intake port 13a and controls introduction of gasoline vapor into the cylinder 4. The exhaust side valve mechanism 11 b opens and closes the exhaust port 13 b to control the exhaust of combustion gas from the cylinder 4.
Reference numeral 6 denotes a crankcase in which the crankshaft 15 is housed, and the crankcase 6 is connected to the inside of the oil pan 3 below.
7a and 7b are oil return holes for returning oil (lubricating oil) supplied from the oil pan 3 to the valve operating chamber 5 to the oil pan. One ends 8 a and 8 b of the oil return holes 7 a and 7 b open to the valve operating chamber 5, and the other ends 9 a and 9 b open to the crankcase 6.
FIG. 2 is an enlarged cross-sectional view of a portion A in FIG. 1 and shows a structure around one end 8b of the oil return hole 7b opened to the valve operating chamber 5.
The inner wall of the oil return hole 7b is made of polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene. It is made of a fluororesin selected from a copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and polyphenylene sulfide (PPS). Polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer (ETFE) Polyvinylidene fluoride (PVDF) and polychlorotrifluoroethylene (PCTFE) are called so-called Teflon (trade name of DuPont).
Since the fluororesin is excellent in heat resistance, it can be used in an engine at a high temperature. Moreover, since it is excellent in non-adhesiveness and low friction properties, it is difficult to stick even with an oil component.
As a method of forming the inner walls of the oil return holes 7a and 7b with the above-mentioned fluororesin, there is a method of coating the inner walls of the oil return holes 7a and 7b with a fluororesin coating 16a and 16b as shown in FIG. For example, the liquid paint containing the above-mentioned fluororesin is spray coated on the inner walls of the oil return holes 7a and 7b to form a thin film of fluororesin and then baked. Alternatively, a powder coating is electrostatically powder coated on the inner walls of the oil return holes 7a and 7b to form a thin film of fluororesin and then baked.
When the engine (internal combustion engine) having the above-described structure is applied to, for example, a four-cycle engine, intake of gasoline vapor into the cylinder 4 → compression of gasoline vapor within the cylinder 4 → explosion (combustion) → exhaust of combustion gas Is repeated, and the piston 14 is moved up and down, and the vertical movement of the piston 14 is changed to the rotational movement of the crankshaft 15 to rotate the tire of the automobile.
During this time, the oil is used by using an oil pump (not shown) so that the movable mechanism such as the crankshaft 15 and the camshafts 12a and 12b can move smoothly and the temperature of the movable mechanism does not rise. Oil (lubricating oil) 10 stored in the pan 3 is circulated inside the engine. Finally, the engine oil is returned from the valve operating chamber 5 to the oil pan 3 through the oil return holes 7a and 7b.
On the other hand, blow-by gas leaking from the cylinder 4 to the crankcase 6 is sent from the crankcase 6 to the valve operating chamber 5 through the oil return holes 7a and 7b, and is further returned from the valve operating chamber 5 to the intake system. Reburned.
According to the embodiment of the present invention, the inner walls of the oil return holes 7a and 7b are made of fluororesin such as Teflon, which is excellent in non-adhesiveness and low friction, so that carbon contained in blow-by gas and oil Inclusions and the like are less likely to adhere to the inner walls of the oil return holes 7a and 7b.
As a result, the oil return holes 7a and 7b can maintain a good flow of blow-by gas and oil for a long time, so that the deterioration of the oil can be prevented and the performance of the engine can be maintained for a long time.
Although the oil return passage structure in the internal combustion engine of the present invention has been described in detail according to the embodiments, the scope of the invention is not limited to the examples specifically shown in the above embodiments, and the gist of the invention Modifications of the above-described embodiment without departing from the scope of the present invention are included in the scope of the present invention.
For example, in order to form the inner walls of the oil return holes 7a and 7b with a desired fluororesin, the inner walls of the oil return holes 7a and 7b are covered with the fluororesin coatings 16a and 16b. However, the present invention is not limited to this. A part of the structure of the cylinder head 2 and the cylinder block 1 including the oil return holes 7a and 7b and the periphery thereof is formed by using fluororesin, and then the part is fitted or attached to the cylinder head or the cylinder block. You may do it.

  It is sectional drawing which shows the oil return channel | path structure in the internal combustion engine which concerns on embodiment of this invention.   It is an expanded sectional view of the A section of FIG.

1 Cylinder block 2 Cylinder head 3 Oil pan 4 Cylinder (combustion chamber)
5 Valve operating chamber 6 Crankcases 7a, 7b Oil return holes 8a, 8b One end 9a, 9b of oil return hole opened in the valve operating chamber 10 The other end 10 of oil return hole opened in the valve operating chamber Oil (lubricating oil)
11a Intake side valve mechanism 11b Exhaust side valve mechanisms 12a, 12b Camshaft 13a Intake port 13b Exhaust port 14 Piston 15 Crankshafts 16a, 16b Fluoropolymer coating 17 Head cover

Claims (3)

A valve operating chamber having a camshaft for controlling the intake side valve mechanism and the exhaust side valve mechanism;
A crankcase with a crankshaft and an oil pan;
An oil return hole that connects the valve operating chamber and the crankcase and returns oil supplied from the oil pan to the valve operating chamber to the oil pan;
The inner walls of the oil return holes are polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene. An internal combustion engine characterized by being made of a fluororesin selected from a copolymer (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), and polyphenylene sulfide (PPS). Oil return passage structure.   A cylinder head that forms the valve operating chamber and has an upper part of the oil return hole, and a cylinder block that forms the crankcase and has a lower part of the oil return hole. Item 2. An oil return passage structure for an internal combustion engine according to Item 1.   2. The oil return passage structure for an internal combustion engine according to claim 1, wherein the entire inner wall of the oil return hole is covered with the fluororesin coating.

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