JPS636428Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a heating device for a fuel pump chamber that can be employed, for example, in a diesel engine having a fuel injection pump chamber at the front of a cylinder block. The purpose is to prevent a drop in fuel temperature in the main fuel pipe or fuel pump and the resulting poor circulation when using a fuel pump, as well as to improve the sound insulation effect.

Conventionally, the cover 1 is generally a single piece made of sheet metal, as shown in FIG. In FIG. 1, the fuel pumps 2 are attached to the cylinder block 3, and the fuel inlet of each fuel pump 2 is connected to the main fuel pipe 5 through a pipe joint 4.
is connected to. A discharge port 6 of the fuel pump 2 is connected to a fuel injection nozzle 8 via a high pressure pipe 7.
Cover 1 includes fuel pump 2, main fuel pipe 5, and high pressure pipe 7
The cylinder block 3 is located at a position that covers the front opening of the fuel pump chamber 9, which accommodates a portion of the fuel pump chamber 9, and by screwing the presser bolt 10 through the hole in the cover 1 into the threaded hole provided in the boss portion 11 of the cylinder block 3, the peripheral edge of the cylinder block 3 is closed. It is pressed against the front surface of the block 3 and the cylinder head 12. In FIG. 1, 13 is a fuel pump drive cam, 14 is a cylinder liner, and 15 is a piston.

If the cover 1 of the fuel pump chamber 9 is made of a relatively thin piece of sheet metal as shown in Figure 1, especially if low-quality oil with high viscosity is used as fuel, the fuel may be heated to nearly 100°C. Even though the fuel is being supplied into the main fuel pipe 5, the fuel pump chamber 9 is not kept sufficiently warm, so that while the fuel is passing through the narrow fuel passages in the fuel main pipe 5 and the fuel pump 2 in the fuel pump chamber 9, The viscosity of the fuel increases, making it difficult for the fuel to flow, reducing engine performance, or in extreme cases, causing the fuel to stop flowing.

The purpose of this invention is to solve the above-mentioned conventional problems, and the cover that covers the front opening of the fuel pump chamber of the engine is made of a sheet metal inner cover and a number of boss nuts that also serve as spacers fixed to the outer surface of the inner cover. , a sanderch structure consisting of a sheet metal outer cover that contacts the boss nut, an outer cover fixing bolt that screws into the boss nut, and a heat insulating material filled in the space between both covers, and the periphery of the space is integrated with the cover. It is characterized by being closed with a bent flange, and an embodiment is shown in FIG. The cover unit 20 in FIG. 2 is shown from the left side of the longitudinal section, whereas the cover 1 of FIG. 1 is shown from the right side of the longitudinal section. It is a molded product,
A plurality of boss nuts 23 that also serve as spacers are welded to the outer surface of the inner cover 21 (right side in FIG. 2), and the outer cover 22 has holes 24 at positions corresponding to the screw holes of each boss nut 23. A bolt 25 is screwed into the nut 23 through the hole 24, so that the distance L between the inner and outer covers 21, 22 is set to, for example, 10 mm. The outer cover 22 is provided with a bent flange 26 toward the inner cover 21 on its outer peripheral edge, and this flange 26 faces the outer peripheral surface of the inner cover 21 with a slight gap therebetween. Inner and outer covers 21, 22
has holes 27 and 28 for passing the presser bolts 10 through, and a reinforcing ring 29 made of sheet metal is welded to the inner cover 21 to create a space 30' surrounding the bolt holes 27 and 28.
is blocked. A heat insulating material 30 is filled in the space 30'. The illustrated heat insulating material 30 is made of glass mat, for example, and has a thickness of 20 mm in a free state and is compressed to a thickness of 10 mm by sandwiching it between the inner and outer covers 21 and 22. 31 and 32 are support legs welded to the inner surface of the inner cover 21.

Attach the cover unit 20 shown in FIG.
When the support legs 31 and 32 are fastened to the cylinder block in the same manner as in the prior art, the supporting legs 31 and 32 come into pressure contact with the surfaces of the cylinder head and cylinder block, thereby sealing the fuel pump chamber.

As explained above, in the present invention, the cover unit 20 has a sandwich structure consisting of the inner and outer covers 21, 22 and the heat insulating material 30 filled in the space 30' between them. Compared to No. 1, the heat insulation effect on the fuel pump chamber is significantly improved, and the amount of heat radiated from the fuel pump chamber is significantly reduced. Therefore, when using low quality oil with high viscosity as fuel, even if the fuel is once heated to nearly 100°C and supplied to the main fuel pipe 5, the fuel is still passing through the narrow passage in the main fuel pipe 5 and the fuel pump 2. However, the temperature hardly decreases during the fuel injection process, and problems such as the fuel becoming difficult to flow or not flowing can be reliably prevented. Moreover, since the inner and outer covers 21 and 22 are made of sheet metal, they are not only easier to manufacture than when the cover itself is made of thick cast iron, but are also lighter and easier to handle. On top of that, inner and outer covers 2
Since the space 30' between 1 and 22 is filled with a heat insulating material 30, even when the inner cover 21 is kept at a high temperature, the outer cover 22 can be kept at a low temperature, and it is possible to keep the outer cover 22 at a low temperature. You no longer have to worry about getting burned when If oil seeps into the heat insulating material 30, the heat insulating effect will be lost, but since the inner and outer covers 21 and 22 are not adhesive structures, the outer cover 2 can be removed by removing the bolts 25.
2 can be removed, and the internal heat insulating material 30 can be easily replaced. This has the advantage of maintaining a high heat retention effect at all times. Moreover, the amount of heat insulating material (filling density) and material can be easily changed depending on the heat insulating temperature inside the pump chamber 9.
There is an advantage that the inside of the pump chamber 9 can be easily maintained at an optimum temperature. Since the inner and outer covers 21 and 22 are integrated by bolts 25, the operation of attaching and detaching the cover unit 20 is the same as that of a conventional one-piece cover, making it easy to handle. Further, according to the present invention, for example, the outer cover 22
A bent flange 26 is provided on the outer peripheral edge of the space 3.
Since 0' was made substantially airtight as shown in Figure 2,
Low quality asbestos can also be used as the heat insulating material 30, and the flange 26 prevents asbestos powder from scattering to the outside. In place of the support legs 31 and 32 shown in FIG. 2, a gasket made of a rubber-like elastic material with high heat resistance may be fixed to the inner and outer peripheral portions of the cover unit 20.

[Brief explanation of the drawing]

Figure 1 is a vertical right side view showing a conventional device;
The figure is a vertical left side view of a single cover unit according to the present invention. 9... Fuel pump chamber, 20... Cover unit, 21, 22... Inner/outer cover, 30... Heat insulating material, 30'... Space.

Claims (1)

[Scope of utility model registration request] The cover that covers the front opening of the fuel pump chamber of the engine includes a sheet metal inner cover and a number of boss nuts that also serve as spacers fixed to the outer surface of this inner cover.
The sandwich structure consists of a sheet metal outer cover that contacts the boss nut, an outer cover fixing bolt that screws into the boss nut, and a heat insulating material filled in the space between both covers. A fuel pump chamber heat retention device characterized by being closed with a bent flange.