Oil supply port structure of engine

Abstract

This oil supply port structure provided for a cylinder head cover (1) of an engine is provided with a cylindrical part (3) constituting an oil supply port (2) into which a nozzle of an oil jug is inserted, having an upper end part to which a filler cap is detachably attached, and having a lower part exposed to a space inside the cylinder head cover (1), a bottom wall part (6) formed integrally with the cylindrical part (3) so as to cover the lower end of the cylindrical part (3), and two openings (8, 9) formed in a lower lateral face of the cylindrical part (3) along the bottom wall part (6). Because the bottom wall part (6) is provided, even if putting on the filler cap is forgotten, it will be difficult for oil droplets of lubricating oil scattered by a camshaft to enter the oil supply port (2).

Description

Fuel filler structure of engine

[0001] The present invention relates to a fuel filler structure provided in the upper surface portion of an engine housing.

[0002] A fuel filler for replenishing lubricating oil is disposed in the upper surface portion of the engine housing, generally in the cylinder head cover, and a filler cap is detachably attached to the upper end thereof.

[0003] In such an engine fuel filler, if the engine is started with the filler cap forgotten to be closed after refueling, the lubricating oil will scatter to the outside from the fuel filler.

[0004] Patent Document 1 describes that in order to suppress the scattering of the lubricating oil from the inside, a lid made of heat-resistant rubber is attached to the lower end opening of the fuel filler. This lid is fixed at a part of the circumference, and when the nozzle of the oil can is inserted into the fuel filler, it elastically deforms downward, and when the nozzle of the oil can is pulled out, it returns to a state where the lower end opening of the fuel filler is closed by elasticity.

[0005] However, in a mass-produced engine, the configuration of attaching such a lid made of a separate part to the fuel filler has low mass productivity and is not preferable.

[0006] Japanese Utility Model Laid-Open No. 5-52209

[0007] The present invention is a fuel filler structure provided in the upper surface portion of an engine housing, which constitutes a fuel filler into which the nozzle of an oil can is inserted, and a filler cap is detachably attached to the upper end portion, and a cylindrical portion whose lower portion is exposed to the space inside the housing, a bottom wall portion integrally formed with the cylindrical portion so as to cover the lower end of the cylindrical portion, and an opening formed in the lower side surface of the cylindrical portion along the bottom wall portion.

[0008] In such a configuration, since the lower end of the cylindrical portion constituting the fuel filler is covered by the bottom wall portion, if the filler cap is forgotten to be attached, the scattering of the lubricating oil from the inside of the housing is suppressed. And since the bottom wall portion is integrally formed with the cylindrical portion, it is low-cost and excellent in mass productivity.

[0009] A plan view from above the engine showing the fuel filler port structure of one embodiment. A cross-sectional view along line A-A in Figure 1. A cross-sectional view along line B-B in Figure 1. A cross-sectional view along line C-C in Figure 1. A front view from the direction of arrow D in Figure 1.

[0010] Hereinafter, an embodiment of this invention will be described in detail with reference to the drawings. Figures 1 to 5 show the fuel filler port structure of an engine according to one embodiment. In this embodiment, for example, the fuel filler port structure is provided on the upper surface portion of a cylinder head cover 1, which is part of the housing of an in-line multi-cylinder engine. The cylinder head cover 1 is mounted on the upper surface of a cylinder head (not shown) and forms a space between itself and the cylinder head for housing, for example, a pair of camshafts. The illustrated cylinder head cover 1 is made of die-cast aluminum alloy, for example.

[0011] The cylinder head cover 1 includes a cylindrical portion 3 that constitutes an oil filler port 2 into which the nozzle of an oil jug is inserted during refueling. The cylindrical portion 3 is substantially cylindrical in shape and extends in the vertical direction, and a filler cap (not shown) is detachably attached to its upper end. Specifically, as shown in Figures 2 to 4, the inner circumferential surface of the upper end of the oil filler port 2 is provided with a threaded portion 4 (the threads are not shown) into which the filler cap is screwed. The lower part of the cylindrical portion 3 is exposed to the internal space of the cylinder head cover 1, as shown in Figures 2 and 3. In the illustrated example, the cylindrical portion 3 is positioned relatively high relative to the upper surface of the cylinder head cover 1 so as not to protrude significantly into the interior of the cylinder head cover 1 where the camshaft is located, and an annular space 5 that becomes part of the internal space is formed so as to surround the entire circumference of the lower part of the cylindrical portion 3 (see Figures 2 and 3).

[0012] As shown in Figure 5, the cylindrical portion 3 has a frustoconical shape when viewed from the outside, and the annular space 5 described above exists inside this frustoconical portion. If there is sufficient space inside the cylinder head cover 1, the lower part of the cylindrical portion 3 may protrude into the inside of the cylinder head cover 1.

[0013] The cylindrical portion 3 has an appropriate length so that the nozzle of the oil jug can be fully inserted. It is also equipped with a bottom wall portion 6 which is integrally formed with the cylindrical portion 3 so as to cover the lower end of the cylindrical portion 3 surrounded by the annular space 5. The bottom wall portion 6 has a generally flat shape. In other words, the lower end of the oil filler port 2 into which the nozzle of the oil jug is inserted is closed off by the bottom wall portion 6.

[0014] In this manner, two openings 8 and 9 are formed on the lower side surface of the cylindrical portion 3, which is closed by the bottom wall portion 6, at a height along the bottom wall portion 6. These two openings 8 and 9 are each roughly rectangular in shape and, as is clear from Figures 2 to 4, are located opposite each other.

[0015] Figure 4 shows the configuration of the cylindrical section 3 in the orientation when the engine is mounted on the vehicle. In this mounted state, the engine is in a slant position, so the cylindrical section 3 as a whole is slightly tilted, and the bottom wall section 6 is inclined with respect to the horizontal plane. Due to this inclination, one of the openings 8 is located at the lowest point of the bottom wall section 6. In the illustrated example, compared to the opening 9 which has an aspect ratio close to a square as shown in Figures 2 and 3, the opening 8 has an aspect ratio that is elongated vertically.

[0016] As shown in Figure 4, the illustrated cylinder head cover 1 integrally includes a cam carrier portion 11 that rotatably supports the camshaft. As can be understood from the positional relationship between the cam carrier portion 11 and the bearing surface 11a, the cylindrical portion 3 that constitutes the oil filler port 2 is located above the camshaft.

[0017] The cylindrical portion 3 and bottom wall portion 6, which have the openings 8 and 9 described above, are formed by die casting as part of the cylinder head cover 1. Therefore, the inner circumferential surface 3a of the cylindrical portion 3, which becomes the oil filler port 2, and the outer circumferential surface 3b exposed to the annular space 5 are formed as inclined surfaces with upward and downward draft angles, respectively. In other words, the inner circumferential surface 3a and the outer circumferential surface 3b are generally conical surfaces. In particular, the draft angle is set to a size that takes into account the formation of the openings 8 and 9 in the cylindrical portion 3.

[0018] With the above configuration, the tip of the cylindrical part 3 which serves as the fuel filler port 2 is covered by the bottom wall 6, making it difficult for oil droplets scattered by the high-speed rotating camshaft to enter the fuel filler port 2. Therefore, even if the engine is operated without the filler cap installed, the scattering of lubricating oil from the fuel filler port 2 is sufficiently suppressed.

[0019] Furthermore, its simple structure and ease of manufacturing by die-casting make it highly suitable for mass production.

[0020] During refueling, the tip of the nozzle of the oil jug, once inserted appropriately, will come into contact with the bottom wall 6, preventing further insertion and thus making it easy to adjust the position of the oil jug nozzle. By injecting lubricating oil with the nozzle tip slightly away from the bottom wall 6, refueling can be performed smoothly through the openings 8 and 9. In particular, since the two openings 8 and 9 are positioned opposite each other, refueling can be performed smoothly without the oil level rising during injection.

[0021] Furthermore, as shown in Figure 4, the bottom wall portion 6 is inclined toward one of the openings 8, which allows for a smoother flow of lubricating oil and prevents lubricating oil from remaining on the bottom wall portion 6.

[0022] Furthermore, the presence of a rigid bottom wall 6 at the lower end of the fuel filler port 2 makes it less likely for foreign objects, such as bolts, to fall into the fuel filler port 2 and into the internal space.

[0023] Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the cylinder head cover 1 having the cylindrical portion 3 is made of die-cast aluminum alloy, but it may be a cylinder head cover made of synthetic resin. Also, the engine housing may be made of a component other than the cylinder head cover.

Claims

1. An engine fuel filler structure provided on the upper surface of the engine housing, comprising: a cylindrical portion that constitutes a fuel filler into which the nozzle of an oil jug is inserted, and into which a filler cap is detachably attached at the upper end, and whose lower part is exposed to the space inside the housing; a bottom wall portion formed integrally with the cylindrical portion so as to cover the lower end of the cylindrical portion; and an opening formed on the lower side surface of the cylindrical portion along the bottom wall portion.

2. The engine fuel filler port structure according to claim 1, wherein the above-mentioned opening includes two openings located opposite each other.

3. The fuel filler port structure for an engine according to claim 1, wherein the inner and outer circumferential surfaces of the cylindrical portion are formed as inclined surfaces having upward and downward draft angles, respectively.

4. The engine fuel filler port structure according to claim 1, wherein, when the engine is mounted in a vehicle, the bottom wall portion is inclined with respect to the horizontal plane, and the opening is provided at the lowest position due to this inclination.

5. The engine oil filler port structure according to claim 1, wherein the housing has a rotating body lubricated by lubricating oil inside, and the cylindrical portion is provided at a position above the rotating body.

6. The engine oil filler port structure according to claim 5, wherein the housing is a cylinder head cover and the rotating body is a camshaft.

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