High-pressure fuel pipe structure for vehicle

Abstract

To prevent corrosion of a high-pressure fuel pipe without impairing sound absorption performance of an insulator.SOLUTION: A high-pressure fuel pipe structure 24 for a vehicle comprises a high-pressure fuel pipe 30 and an insulator 31. The high-pressure fuel pipe 30 is inserted into a concave part of the insulator 31, which has a U-shaped cross section. The insulator 31 covers the high-pressure fuel pipe 30 with an open-cell urethane foam 32A on the inside and a closed-cell urethane foam 33A on the outside. The closed-cell urethane foam 33A has a partially annular cross section, and is disposed so as to be located vertically above the high-pressure fuel pipe 30 when the high-pressure fuel pipe structure 24 for the vehicle is placed on the vehicle 10.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a high-pressure fuel piping structure for a vehicle. [Background technology]

[0002] Known examples of conventional engine covers and soundproofing structures for engines include the structure described in Patent Document 1. The engine cover is made of a laminated structure in which an outer sound-insulating layer having sound-insulating properties and an inner sound-absorbing layer made of a foam molded body are laminated together, and is attached to cover at least a portion of the engine on which noise-generating equipment protrudes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-207593 Summary of the Invention [Problem to be solved by the invention]

[0004] High-pressure fuel pipes are also required to have a soundproof structure and are sometimes wrapped in insulators. Insulators wrapped around high-pressure fuel pipes tend to absorb moisture in wet surrounding environments and retain it for long periods of time. Moisture retained by the insulators over long periods of time may come into contact with the high-pressure fuel pipe and cause corrosion.

[0005] The present invention has been made in view of the above circumstances, and relates to a high-pressure fuel piping structure for a vehicle that prevents corrosion of the high-pressure fuel piping without impairing the sound-absorbing performance of the insulator. [Means for solving the problem]

[0006] The high-pressure fuel piping structure for a vehicle of the present invention is a high-pressure fuel piping structure for a vehicle provided on a vehicle, characterized by comprising an insulator formed by stacking an open-cell foam molding as a first region and a closed-cell foam molding as a second region smaller than the first region, and a high-pressure fuel piping covered by the insulator with the closed-cell foam molding on the outside. [Effects of the Invention]

[0007] A high-pressure fuel pipe structure for a vehicle according to one embodiment of the present invention prevents corrosion of the high-pressure fuel pipe without impairing the sound-absorbing performance of the insulator. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view illustrating a vehicle equipped with a fuel piping system including a high-pressure fuel piping structure for a vehicle according to an embodiment of the present invention; [Figure 2] 1 is a plan view illustrating an overview of an engine room in which a high-pressure fuel piping structure for a vehicle according to an embodiment of the present invention is disposed; [Figure 3] 1 is a cross-sectional view illustrating a high-pressure fuel pipe structure for a vehicle according to an embodiment of the present invention. [Figure 4] FIG. 2 is a cross-sectional view illustrating the cell structure of an open-cell molded article according to one embodiment of the present invention. [Figure 5] FIG. 2 is a cross-sectional view illustrating the cell structure of a closed-cell molded article according to one embodiment of the present invention. [Figure 6] 1 is a cross-sectional view illustrating the sound absorbing and waterproofing effects of a high-pressure fuel pipe structure for a vehicle according to an embodiment of the present invention. [Figure 7] FIG. 10 is a cross-sectional view illustrating a high-pressure fuel pipe structure for a vehicle according to a modified embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a vehicle high-pressure fuel piping structure 24, 25 according to one embodiment of the present invention will be described in detail with reference to the drawings. In the description of this embodiment, the same reference numerals will be used for the same components, and repeated description will be omitted. In the following description, the up-down direction will be referred to as the height direction of the vehicle, the left-right direction will be referred to as the width direction of the vehicle, and the front-rear direction will be referred to as the length direction of the vehicle.

[0010] First, a vehicle 10 equipped with a fuel piping system 20 including high-pressure fuel piping structures 24, 25 for a vehicle will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of a vehicle 10 equipped with a fuel piping system 20 including high-pressure fuel piping structures 24, 25 for a vehicle according to an embodiment.

[0011] The vehicle 10 is equipped with an engine 11 and includes a fuel tank 12 and a fuel piping system 20 that supplies fuel from the fuel tank 12 to the engine 11. The vehicle 10 also includes a radiator 13 for cooling the engine 11. The vehicle 10 also has a grill opening 14 for drawing airflow into the radiator 13. The area around the engine 11 may be subject to water that enters from the grill opening 14 or from below the vehicle 10 due to rainfall, car washing, water splashes, etc., and may also be subject to condensation depending on the environment. A portion of the fuel piping system 20 is disposed around the engine 11 and is therefore in an environment exposed to water, and therefore the fuel piping is made of steel and is subjected to anti-rust treatment such as galvanization.

[0012] The vehicle 10 is an all-wheel drive vehicle, but may be a front-wheel drive vehicle or a rear-wheel drive vehicle. The engine 11 is a horizontally opposed engine, but may be an in-line engine, a V-engine, a rotary engine, or the like. The fuel piping system 20 supplies gasoline as fuel from the fuel tank 12 to the engine 11, but may also supply other fuels such as diesel.

[0013] Next, an overview of the inside of the engine room 15 in which the high-pressure fuel piping structures 24, 25 for a vehicle are arranged will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of an overview of the inside of the engine room 15 in which the high-pressure fuel piping structures 24, 25 for a vehicle according to the embodiment are arranged.

[0014] 2 shows an overhead view of the engine compartment 15 of the vehicle 10. The fuel piping system 20 includes a fuel hose 21, a fuel pump 22, high-pressure fuel piping structures 24 and 25 for a vehicle, delivery pipes 26 and 27, a relief valve 28, and a return pipe 29.

[0015] Fuel hose 21 supplies fuel supplied from a feed pump (low-pressure fuel pump) in fuel tank 12 to fuel pump 22. Fuel hose 21 is connected to the intake port of fuel pump 22. Fuel hose 21 is one of the components constituting a low-pressure fuel system that sends fuel discharged from the feed pump to fuel pump 22.

[0016] Fuel pump 22 draws fuel through fuel hose 21 and creates high pressure in vehicle high-pressure fuel piping structures 24, 25 and delivery pipes 26, 27. Vehicle high-pressure fuel piping structure 24 connects the discharge port of fuel pump 22 to delivery pipe 26 provided on an upper part of a cylinder head on the left side in the vehicle width direction of engine 11, and sends fuel discharged from fuel pump 22 to delivery pipe 26. Vehicle high-pressure fuel piping structure 25 connects delivery pipe 26 to delivery pipe 27 provided on an upper part of a cylinder head on the right side in the vehicle width direction of engine 11.

[0017] Delivery pipe 26 supplies fuel to injectors that inject fuel into combustion chambers of engine 11. Delivery pipe 27 supplies fuel to injectors that inject fuel into combustion chambers of engine 11. Delivery pipe 27 is connected to return pipe 29 via relief valve 28. Return pipe 29 returns fuel to fuel tank 12 when excessive pressure is released by relief valve 28. High-pressure fuel piping structures 24, 25 for a vehicle and delivery pipes 26, 27 are components that make up a high-pressure fuel system that sends fuel discharged by fuel pump 22 to the injectors.

[0018] The high-pressure fuel piping structures 24, 25 for a vehicle may generate pulsating noise when delivering high-pressure fuel. The pulsating noise may be caused by the fuel pump 22, the injector, or both. Because the high-pressure fuel piping structures 24, 25 for a vehicle are located near the engine 11, they are exposed to a water-damaged environment where there is a risk of perforation due to corrosion. The high-pressure fuel piping structures 24, 25 for a vehicle have a soundproofing structure that covers the piping with an insulator, which will be described later, thereby reducing the risk of perforation due to corrosion even in a water-damaged environment and making it possible to suppress the pulsating noise.

[0019] Next, the configuration of the high-pressure fuel piping structure 24 for a vehicle will be described with reference to Figure 3, which shows the AA cross section of Figure 2. The open-cell urethane foam will be described with reference to Figure 4. The closed-cell urethane foam will be described with reference to Figure 5. Figure 3 is a diagram showing an example of a cross-sectional view of the high-pressure fuel piping structure 24 for a vehicle according to an embodiment. Figure 4 is a diagram showing an example of the cell structure of the open-cell molded product 32 according to an embodiment. Figure 5 is a diagram showing an example of the cell structure of the closed-cell molded product 33 according to an embodiment. The high-pressure fuel piping structure 25 for a vehicle can also have a configuration similar to that of the high-pressure fuel piping structure 24 for a vehicle.

[0020] As shown in Figure 3, the high-pressure fuel piping structure 24 for a vehicle includes a high-pressure fuel piping 30 and an insulator 31. The high-pressure fuel piping 30 is a steel pipe with an annular cross section that has been treated with an anti-rust treatment such as zinc plating. The insulator 31 has a U-shaped cross section. The high-pressure fuel piping 30 is inserted into a recess in the U-shaped cross section of the insulator 31. In other words, the high-pressure fuel piping 30 is covered by the insulator 31, which also has a U-shaped cross section.

[0021] The insulator 31 is formed by laminating, for example, an open-cell urethane foam 32A as the open-cell molded body 32 and a closed-cell urethane foam 33A as the closed-cell molded body 33. The open-cell urethane foam 32A and the closed-cell urethane foam 33A may be laminated together by adhesion, welding, or by abutment by fitting or the like.

[0022] Insulator 31 covers high-pressure fuel pipe 30 with open-cell urethane foam 32A on the inside and closed-cell urethane foam 33A on the outside. Closed-cell urethane foam 33A has a partially annular cross section, in other words, an annular sector cross section. Open-cell urethane foam 32A and closed-cell urethane foam 33A form a U-shaped cross section. Closed-cell urethane foam 33A is disposed so as to be located vertically above high-pressure fuel pipe 30 when vehicle high-pressure fuel piping structure 24 is placed on vehicle 10.

[0023] Insulator 31 has open-cell urethane foam 32A arranged in a first region indicated by diagonal hatching. The first region is an area sufficient to abut against and cover high-pressure fuel pipe 30. Furthermore, insulator 31 has closed-cell urethane foam 33A arranged in a second region indicated by cross-hatching. The second region is an area that is on the outside when viewed from high-pressure fuel pipe 30.

[0024] The open-cell urethane foam 32A is an example of an open-cell molded product made from urethane or polyurethane, but may be made from styrene or polystyrene instead of urethane, or from other raw materials such as resin or rubber. The closed-cell urethane foam 33A is an example of a closed-cell molded product made from urethane or polyurethane, but may be made from styrene or polystyrene instead of urethane, or from other raw materials such as resin or rubber. Note that open cells may be referred to as open foam, and closed cells may be referred to as closed foam.

[0025] The open-cell urethane foam 32A has an open-cell structure 34 in which multiple cells are interconnected. The open-cell structure 34 allows fluids such as air and water to easily enter and exit the open-cell urethane foam 32A. The open-cell urethane foam 32A has excellent sound absorption performance because sound waves are attenuated frequently as they propagate through the open-cell structure 34. The excellent sound absorption performance of the open-cell urethane foam 32A absorbs pulsating noise originating from the high-pressure fuel pipe 30, contributing to improved quietness of the vehicle 10. On the other hand, the open-cell urethane foam 32A also has excellent water retention performance due to the open-cell structure 34. The water retention performance of the open-cell urethane foam 32A may retain moisture that has penetrated the open-cell urethane foam 32A, potentially exposing the high-pressure fuel pipe 30 to a wet environment for an extended period of time.

[0026] The closed-cell urethane foam 33A has a closed-cell structure 35 in which multiple cells are separated from one another. The closed-cell structure 35 makes it difficult for air, water, and other fluids to enter and exit the closed-cell urethane foam 33A. The closed-cell structure 35 gives the closed-cell urethane foam 33A excellent waterproofing performance. The excellent waterproofing performance of the closed-cell urethane foam 33A protects the high-pressure fuel pipe 30 from a water-exposed environment and contributes to improved rust prevention. On the other hand, the closed-cell urethane foam 33A has poor sound absorption performance because there is little opportunity for sound waves to attenuate as they propagate.

[0027] However, the second region where closed-cell urethane foam 33A is arranged is smaller than the first region where open-cell urethane foam 32A is arranged, and is limited to the extent necessary to prevent water from entering high-pressure fuel pipe 30. For example, in the cross section of vehicle high-pressure fuel piping structure 24, the cross-sectional area of ​​the second region where closed-cell urethane foam 33A is arranged is smaller than the cross-sectional area of ​​the first region where open-cell urethane foam 32A is arranged.

[0028] As a result, the high-pressure fuel piping structure 24 for a vehicle can absorb pulsating noise from the high-pressure fuel piping 30 using the open-cell urethane foam 32A with a large area, thereby improving the quietness of the vehicle 10. Furthermore, the high-pressure fuel piping structure 24 for a vehicle can prevent water from getting into the high-pressure fuel piping 30 via the open-cell urethane foam 32A using the closed-cell urethane foam 33A, thereby preventing corrosion of the high-pressure fuel piping 30. Furthermore, the high-pressure fuel piping structure 24 for a vehicle can prevent water from getting into the high-pressure fuel piping 30 while maintaining sound absorption performance, while making the insulator 31 compact.

[0029] Next, the sound absorbing and waterproofing effects of the vehicle high-pressure fuel piping structure 24 will be described with reference to Fig. 6. Fig. 6 is a diagram showing an example of a sound absorbing mechanism and a waterproofing mechanism of the vehicle high-pressure fuel piping structure of the embodiment. Note that solid arrows in Fig. 6 indicate sound propagation or air vibration, and dashed arrows indicate water flow.

[0030] The closed-cell urethane foam 33A is located above the high-pressure fuel pipe 30 and is layered on the open-cell urethane foam 32A so as to exceed the width of the high-pressure fuel pipe 30. As a result, the closed-cell urethane foam 33A prevents water from entering the open-cell urethane foam 32A above the high-pressure fuel pipe 30. In the high-pressure fuel pipe structure 24 for a vehicle, the closed-cell urethane foam 33A functions as a canopy for the open-cell urethane foam 32A above the high-pressure fuel pipe 30, thereby protecting the open-cell urethane foam 32A above the high-pressure fuel pipe 30 from water intrusion. As a result, the high-pressure fuel pipe structure 24 for a vehicle can prevent corrosion of the high-pressure fuel pipe 30 without compromising the sound-absorbing performance of the open-cell urethane foam 32A.

[0031] Furthermore, although the closed-cell urethane foam 33A exceeds the width of the high-pressure fuel pipe 30, it does not extend laterally of the high-pressure fuel pipe 30. This type of high-pressure fuel pipe structure 24 for a vehicle allows water that has entered the open-cell urethane foam 32A to flow down along the surface, but there is a risk that some of the water may seep in laterally. However, water that has entered the open-cell urethane foam 32A flows down the interior of the open-cell urethane foam 32A due to gravity and flows out the lower end. Therefore, this type of high-pressure fuel pipe structure 24 for a vehicle prevents water from entering the high-pressure fuel pipe 30 and prevents corrosion of the high-pressure fuel pipe 30. Furthermore, this type of high-pressure fuel pipe structure 24 for a vehicle can maximize the first region in which the open-cell urethane foam 32A is disposed, thereby simultaneously preventing water from entering the high-pressure fuel pipe 30 and maintaining sound-absorbing performance.

[0032] The lower end of open-cell urethane foam 32A extends downward below the lower surface of high-pressure fuel pipe 30. This prevents water flowing down from the end of open-cell urethane foam 32A from contacting high-pressure fuel pipe 30.

[0033] Next, a modified example of the high-pressure fuel piping structure 24 for a vehicle will be described with reference to Fig. 7. Fig. 7 is a diagram showing an example of a cross-sectional view of a high-pressure fuel piping structure 36 for a vehicle according to a modified embodiment of the present invention. The high-pressure fuel piping structure 36 for a vehicle is obtained by applying a water-repellent coating 38 to the high-pressure fuel piping structure 24 for a vehicle.

[0034] The high-pressure fuel pipe structure 36 for a vehicle has a water-repellent coating 38 on the surface of the insulator 31 that is exposed to a water environment. The water-repellent coating 38 may be formed by applying or impregnating a water-repellent material to the surface of the insulator 31 that is exposed to a water environment, or by laminating or adhering a water-repellent film or the like to the insulator 31. The high-pressure fuel pipe structure 36 for a vehicle may use a water-repellent material such as fluororesin, silicone resin, or other known materials.

[0035] The high-pressure fuel piping structure 36 for a vehicle does not have the water-repellent coating 38 on surfaces of the insulator 31 that are not exposed to a water-susceptible environment. For example, the high-pressure fuel piping structure 36 for a vehicle does not have the water-repellent coating 38 on the lower end surface of the open-cell urethane foam 32A in the insulator 31 and on the surface through which the high-pressure fuel piping 30 is inserted.

[0036] As a result, the vehicle high-pressure fuel piping structure 36 is able to prevent water from entering the high-pressure fuel piping 30 on the surface exposed to a water environment while maintaining sound absorption performance. Furthermore, even if water penetrates into the open-cell urethane foam 32A, the vehicle high-pressure fuel piping structure 36 is able to drain water from the surface that does not have the water-repellent coating 38. Note that the vehicle high-pressure fuel piping structure 36 may have the water-repellent coating 38 on the entire surface of the insulator 31.

[0037] It should be noted that the disclosed embodiments are illustrative in all respects and should not be considered limiting. Furthermore, the configurations of the above-described embodiments and modifications may be combined and applied. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0038] 10 vehicles 11 Engine 12 Fuel tank 13 Radiator 14 Grill opening 15 Engine Room 20 Fuel piping system 21 Fuel hose 22 Fuel pump 24, 25, 36 High-pressure fuel piping structure for vehicles 26,27 Delivery pipe 28 Relief valve 29 Return pipe 30 High-pressure fuel pipe 31 Insulator 32 Open-cell molded body 32A Open-cell urethane foam 33 Closed-cell molding 33A Closed-cell urethane foam 34 Open-cell structure 35 Closed-cell structure 38 Water-repellent coating

Claims

1. A high-pressure fuel piping structure for a vehicle provided in a vehicle, an insulator in which an open-cell molded body is laminated as a first region and a closed-cell molded body is laminated as a second region smaller than the first region; a high-pressure fuel pipe covered with the insulator with the closed-cell molded article facing outward; A high-pressure fuel piping structure for a vehicle, comprising:

2. 2. The high-pressure fuel piping structure for a vehicle according to claim 1, wherein the insulator is formed by laminating the closed-cell molded articles in a partially annular shape, and the high-pressure fuel piping is inserted into a recess having a U-shaped cross section.

3. 3. The high-pressure fuel piping structure for a vehicle according to claim 2, wherein the closed-cell molded article is located above the high-pressure fuel piping.

4. The open-cell molded article is an open-cell urethane foam, 4. The high-pressure fuel piping structure for a vehicle according to claim 1, wherein the closed-cell molded body is a closed-cell urethane foam.

5. 4. The high-pressure fuel pipe structure for a vehicle according to claim 1, wherein the insulator is coated with a water-repellent material.

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