1. Field of the Invention
The present invention relates to fuel injectors utilized in an internal combustion engines and more particularly, to fuel injectors which can reduce valve noise during the operation.
2. Description of the Related Art
An example of a known fuel injector for an internal combustion engine is disclosed in Japanese Laid-Open Patent Publication No. 2000-240525 and is reproduced in
However, because the jet opening downstream channel 5b is provided within the valve seat 5, the wall thickness B of the valve seat 5 on the downstream side of the jet opening 5a becomes relatively small. Therefore, noise which is caused by contact of the valve 6 with the valve seat 5 is transmitted through the thin portion of the valve seat 5 on the downstream side of the jet opening 5a and leaks to the outside of the fuel injector 7.
It is, accordingly, an object of the present teachings to provide fuel injectors that can prevent leakage of noise, which is caused by contact of the valve with the valve seat, to the outside of the fuel injector.
According to the present invention, a representative injector may comprise a fuel passage, a valve, a valve seat, a jet opening and a jet opening downstream channel. The valve is disposed on the fuel passage and the valve seat receives the valve. The jet opening is formed in the valve seat and through which fuel is exhausted. The jet opening may be opened when the valve is moved apart from the valve seat. When the jet opening is opened, fuel can be exhausted(injected) from the jet opening. The jet opening downstream channel extends downstream from the jet opening through the valve seat and communicates the jet opening to the outside. Thus, fuel exhausted at the jet opening can be injected to the outside via the jet opening downstream channel.
The diameter of the jet opening downstream channel may be arranged and adapted such that the valve seat has a wall thickness to prevent leakage of noise to the outside through the valve seat. Such noise is typically caused by contact of the valve with the valve seat.
According to the present invention, because the diameter of the jet opening downstream channel is designed to be smaller and accordingly, the wall thickness of the valve seat is designed to be greater, the representative injector can effectively prevent leakage of noise to the outside through the valve seat.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.
a) is a sectional view of a valve seat of a fuel injector according to the first representative embodiment of the present invention;
b) is a sectional view of a valve seat of a fuel injector according to the second representative embodiment of the invention;
c) is a sectional view of a valve seat of a fuel injector according to the third representative embodiment of the invention; and
As one aspect of the present teachings, the diameter of the jet opening downstream channel of the representative fuel injector may be designed so as to ensure the diffusability of the fuel exhausted from the jet opening, as well as preventing leakage of noise to the outside through the valve seat.
Especially, the jet opening downstream channel may preferably have a region in which its diameter is substantially double the diameter of the jet opening. The diameter of the jet opening downstream channel may have substantially double the diameter of the jet opening at least in a region right below the jet opening.
Preferably, the length of the jet opening downstream channel along its longitudinal axis may be substantially the same as or larger than the diameter of the jet opening downstream channel. As a result, the leakage of noise to the outside can be more effectively prevented.
Further, as another aspect of the present invention, the representative fuel injector may preferably comprise a first channel and a second channel within the jet opening downstream channel. The first channel may be formed in the region right below the jet opening so as to have a diameter substantially double the diameter of the jet opening. On the other hand, the second channel may be continuously and smoothly connected to the first channel in the region below the first channel. The second channel may be conically enlarged away from the jet opening.
Otherwise, the diameter of the jet opening downstream channel may be substantially double the diameter of the jet opening over its entire region.
Otherwise, the representative fuel injector may preferably comprise a first channel and a second channel within the jet opening downstream channel. The first channel may be formed in the region right below the jet opening so as to have a diameter substantially double the diameter of the jet opening. Especially, the first channel may preferably be arranged and adapted to have a diameter substantially double the diameter of the jet opening such that the valve seat has a wall thickness to prevent leakage of noise to the outside through the valve seat. On the other hand, the second channel may have a diameter larger than the diameter of the first channel over the entire region of the second channel. As a result, the second channel can ensure satisfactory diffusion of fuel exhausted from the jet opening. The first channel and the second channel may preferably be continuously and smoothly connected to each other.
Each of the additional features and method steps disclosed above and below may be utilized separately or in conjunction with other features and method steps to provide improved fuel injector and method for using such fuel injectors and devices utilized therein. Representative examples of the present invention, which examples utilized many of these additional features and method steps in conjunction, will now be described in detail with reference to the drawings. This detailed description is merely intended to teach a person skilled in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed within the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe some representative examples of the invention, which detailed description will now be given with reference to the accompanying drawings.
A first representative embodiment will now be described with reference to
First representative embodiment is now described in reference to
Thus, according to the first representative embodiment, the optimum diameter D1 of the first channel 1b for satisfactory performance of the above-mentioned both functions is provided so as to be substantially double the diameter D2 of the jet opening 1a over the entire region of the first channel 1b. Specifically, according to the first embodiment, the first channel is arranged to have a diameter of substantially 3.0 mm, while the jet opening is arranged to have a diameter of 1.5 mm. Also, according to the first representative embodiment, the optimum length of the first channel 1b in its axial direction (right and left in
The second channel 1c is continuously and smoothly connected to the first channel 1b such that the first and second channel 1b, 1c define the jet opening downstream channel. The second channel 1c is conically enlarged away from the jet opening 1a such that fuel can be satisfactorily diffused by passing through the conically shaped second channel 1c.
A second representative embodiment of the invention will now be described in reference to
A third representative embodiment of the invention will now be described in reference to
The diameter of the first channel 3b is substantially double the diameter of the jet opening 3a over the entire region of the first channel 3b. As a result, relatively larger wall thickness of the valve seat 3 can be ensured over the entire region of the first channel 3b such that leakage of noise to the outside can be alleviated. Further, the diameter of the second channel 3c is larger than that of the first channel 3b over the entire region of the second channel 3c so that satisfactory diffusion of fuel can be ensured.
Number | Date | Country | Kind |
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2003-068897 | Feb 2003 | JP | national |
Number | Name | Date | Kind |
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5054691 | Huang et al. | Oct 1991 | A |
5314122 | Winter | May 1994 | A |
6059205 | Ricco | May 2000 | A |
Number | Date | Country |
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861152 | Mar 1996 | JP |
2000240525 | Sep 2000 | JP |
2000249022 | Sep 2000 | JP |
Number | Date | Country | |
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20040206833 A1 | Oct 2004 | US |