Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
2002-10-25
2004-11-09
Mar, Michael (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
C239S585400, C239S533200, C239S533120, C239S533140
Reexamination Certificate
active
06814312
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on, claims the benefit of priority of, and incorporates by reference the contents of prior Japanese Patent Application No. 2001-340629, filed on Nov. 6, 2001, and No. 2002-238133, filed on Aug. 19, 2002.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for a spraying tip or end of a fuel injection valve that is applicable to a fuel injection valve that supplies fuel to an intake pipe of, for example, an internal combustion engine.
2. Description of the Related Art
Generally, fuel injection valves are known which, for example, are provided at the intake pipe of an internal combustion engine to supply fuel to the engine. Japanese Patent Laid-Open Publication Nos. Hei. 8-277763 and 9-310651 are examples of such a technology.
With improvements in the performance of internal combustion engines, there is a demand for cleaner exhaust emissions in connection with the fuel injection valves of this kind. In particular, improved valves are needed to further vaporize fuel so that the injected fuel spray is comprised of finer particles.
Japanese Patent Laid-Open Publication No. Hei. 8-277763 discloses means for achieving the above purpose. According to the disclosure of the document, a nozzle needle as a valve member forms a flow path that directs fuel toward an injection hole plate in cooperation with the internal circumferential wall of a nozzle body as a valve body. An extension of the tip of the nozzle needle at the outer circumference is positioned outside the circular shape of a plurality of injection holes provided at the tip of the nozzle body at the opening on the inlet side. After fuel strikes the tip of the nozzle body, in other words, the injection hole plate, the fuel forms streams toward the center along the upper surface of the injection hole plate, and the fuel is ejected from the injection holes provided on the way to the center.
According to Japanese Patent Laid-Open Publication No. Hei. 9-310651, while the streams toward the center are formed, the injection holes are provided in slanted directions so that the streams formed toward the injection holes do not interfere with each other around the center of the injection hole plate and do not impede the flow of injection.
In conventional arrangements, the fuel passes at an increased speed into the injection hole inlets positioned on the upper surface of the injection hole plate at the tip of the fuel injection valve. Therefore, the kinetic energy of the injected fuel can be increased and the fuel spray will be fine particles. However, the vacuum air stream in the intake pipe is mixed with the fuel spray injected from the injection holes and forms an air-fuel mixture. The conventional arrangements do not fully take into account the effect of this air stream upon fuel spraying.
Meanwhile, there is a known valve that includes a sleeve provided at the lower surface of the injection hole plate having openings concentric to the group of injection holes at the injection hole plate and having an enlarged diameter (see Japanese Patent Laid-Open Publication No. 2000-145589). According to Japanese Patent Laid-Open Publication No. 2000-145589, the sleeve is made of a resin material and press-fitted onto the outer periphery of the tip end of the fuel injection valve to make it secure.
However, the holding strength to fix the sleeve could be lowered by high temperature creep, etc., and its engagement to the outer periphery of the end of the injection valve could become loose or undone, permitting the sleeve to rotate. Meanwhile, in order to provide the holding strength by press-fitting, excessive compressive stress could be provided to the valve body that forms the end, so that the valve can not be closed as tightly as required when in a fully closed state.
When the holding strength by press fitting is low, the operator might inadvertently rotate the sleeve from a desired position when the injection fuel valve is attached.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages, it is an object of an embodiment of the present invention to provide a fuel injection valve that generates smaller fuel spray particles and permits the valve to be tightly closed and readily assembled by press-fitting. Another object of an embodiment of the present invention is to prevent excessive stresses from being subjected to the valve portion to prevent the sleeve from rotating.
According to a first aspect of the invention, a fluid injection valve includes an injection hole plate provided at a fluid path outlet formed at a tip portion of an end of a valve body, the plate having a plurality of injection holes. Furthermore, a sleeve is fixed to the valve body provided with the injection hole plate. The fluid injection valve injects fluid from the injection holes to control the amount of the fluid and determine the injection direction. The valve body has a bottom wall portion with a valve seat against/from which a valve member abuts/moves away, and a side wall portion provided upright from a peripheral edge of the bottom wall portion that supports the valve member in a reciprocating manner.
The injection hole plate is formed as a cup shape, has its entire circumference joined to the valve body to cover the fuel path, and has a bottom portion with the injection holes to allow the fuel path to communicate with an area outside of the valve structure. There is also a cylindrical portion provided upright from a peripheral edge of the bottom portion and press-fitted onto the side wall portion. The sleeve is a resin sleeve having a resin annular portion with an opening opened toward the downstream side of the fuel injected from the injection hole plate, and a resin cylindrical portion provided upright from a peripheral edge of the resin annular portion and press-fitted onto the side wall portion. One of the sleeve and the injection hole plate has a projection and the other has a cutout groove corresponding to the projection so that the sleeve and the injection hole plate may engage each other.
In general, in a resin sleeve having an opening opened toward the downstream side of fuel injected from the injection hole plate, its holding strength, kept fittingly fixed to the valve body, may be lessened depending upon the state of any high temperature creep as it is press-fitted onto the side wall of the valve body. This could cause the engagement of the sleeve to the outer periphery of the valve body to become undone. Additionally, in order to provide holding strength by press-fitting, excessive compressive stress could be induced into the valve body. Then, the valve may not be able to close as tightly as required in a fully closed state depending upon how much additional pressing force is provided to the sleeve to compensate for the decrease in the holding strength caused by the high temperature creep.
In contrast, in the fuel injection valve according to the invention, one of the sleeve and the injection hole plate has a projection and the other has a cutout groove corresponding to the projection so that the sleeve and the injection hole plate may engage each other. Therefore, without increasing the force of press-fitting the sleeve to compensate for the decrease in the holding strength due to any high temperature creep as in the conventional manner, the outer circumference of the valve body and the sleeve can securely be engaged with each other and the sleeve can be prevented from rotating.
Therefore, the valve tightness in a fully closed state can be secured, while the valve body and the sleeve can be engaged without increasing the force of press-fitting the sleeve. The valve body and the sleeve can more readily be assembled by press-fitting.
According to a second aspect of the invention, in providing the projection to the injection hole plate and the cutout groove corresponding to the projection, to the sleeve, the resin cylindrical portion, press-fitted onto the side wall portion, includes a press-fitting portion that can be press-fitted onto t
Hokao Takayuki
Iwano Akira
Denso Corporation
Gorman Darren
Mar Michael
Nixon & Vanderhye PC
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