Fluid sprinkling – spraying – and diffusing – With means to vibrate or jiggle discharge – By electric transducer
Reexamination Certificate
2002-10-01
2004-05-25
Ganey, Steven J. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
With means to vibrate or jiggle discharge
By electric transducer
C239S533100, C239S583000, C239S584000, C239S585100, C239S585400, C239S596000, C123S472000, C123S498000
Reexamination Certificate
active
06739520
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid injection apparatus for atomizing liquid and injecting the atomized liquid into a liquid injection space.
2. Description of the Related Arts
As such liquid injection apparatuses, a fuel injection apparatus for an internal-combustion engine is known. The fuel injection apparatus for the internal-combustion engine is a so-called electrically controlled fuel injection apparatus comprising a pressurizing pump for pressurizing liquid and an injection valve, and has been widely and practically in use. However, as the electrically controlled fuel injection apparatus is configured in such a manner that the fuel pressurized by the pressurizing pump is injected from the injection port of the electromagnetic injection valve, the droplet size of the injected fuel is relatively large, about 100 &mgr;m at minimum, and further the sizes are not uniform. Such large droplet sizes or uneven droplet sizes of the fuel increase incomplete combustion of fuel when the fuel is burned, thereby causing the increase in toxic emission.
On the other hand, as Japanese Patent Application Laid-open (kokai) No. 54-90416 discloses, a droplet eject apparatus is proposed, wherein the liquid in a liquid supply passage is pressurized by operation of a piezoelectric element to produce ultra-fine droplets of liquid and these droplets of liquid are ejected from an eject port. Apparatuses of the type described use the principle of the ink jet eject apparatus disclosed, for example, in Japanese Patent Application Laid-open (kokai) No. Hei6-40030, or others. In the apparatus, the size of the ejected droplet (the droplet of injected fuel) can be reduced and can be uniform, when compared to the above-mentioned electrically controlled fuel injection apparatus. Therefore, this apparatus can be said to be an excellent apparatus in atomizing fuel.
When the ink jet eject apparatus is used under a relatively steady-state environment with less change in the temperature or pressure (for example, in an office room, or school), it can give its intended performance to inject liquid in the form of droplets of liquid. However, if it is used under such an environment that fluctuates heavily caused by fluctuation of operating conditions, like an internal-combustion engine, it is generally difficult for the apparatus to fully give its intended performance to atomize the fuel. Therefore, no liquid (fuel) injecting apparatus has so far been provided which fully succeeds in atomizing liquid and injecting the liquid in the form of droplets of liquid, by means of using the principle of the ink jet eject apparatus, for a mechanical apparatus with heavily fluctuating environment like an internal-combustion engine.
When such a liquid injection apparatus is applied to mechanical apparatuses like an internal-combustion engine, the liquid injection apparatus is required to securely and stably supply the amount of injection of the liquid required by the mechanical apparatus, and at the same time, to inject the liquid at the injection timing required by the mechanical apparatus without delay. However, since such liquids injecting apparatuses carry out injecting by means of increasing or reducing the pressure of liquid, air bubbles are easily formed in the liquid, and if such air babbles are not removed before they become large, the pressure of the liquid cannot be increased as expected. Therefore, the apparatus cannot satisfy the requirements as to the amount of injection and the injection timing.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to provide a liquid injection apparatus capable of stably accomplishing atomization of liquid and injecting the liquid in the form of uniform minute droplets of liquid. Another object of the present invention is to provide a liquid injection apparatus, which is configured to have the capability of stably injecting liquids even under conditions that the use environment for the liquid injection apparatus such as liquid injection space heavily and suddenly fluctuates. A further object of the present invention is to provide a liquid injection apparatus, which can inject the intended amount of injection of liquid at the intended injection timing, by means of preventing air babbles from being formed in the liquid within the liquid injection apparatus.
In order to achieve the above objects, according to a first aspect of the present invention, there is provided a liquid injection apparatus comprising an injection device including a liquid ejection nozzle having one end exposed to a liquid injection space, a piezoelectric/electrostrictive element, a chamber connected to the other end of the liquid ejection nozzle, the chamber having a volume changed by the operation of the piezoelectric/electrostrictive element, a liquid supply passage connected to the chamber, and a hollow cylindrical liquid filling port allowing the liquid supply passage to communicate with the exterior; pressurizing means for pressurizing liquid; an electromagnetic ejection valve to which liquid pressurized by the pressurizing means is supplied, the electro-magnetic ejection valve including a solenoid valve and an ejection hole which is opened or closed by the solenoid valve, the electromagnetic ejection valve ejecting the pressurized liquid through the ejection hole when the solenoid valve is opened; and a hermetically sealed space forming member for forming a hollow cylindrical hermetically sealed space between the ejection hole of the electro-magnetic ejection valve and the liquid filling port of the injection device, the hermetically sealed space having substantially the same diameter as the diameter of the liquid filling port; liquid ejected from the electro-magnetic ejection valve being atomized by change of volume of the chamber and injected in the form of droplets from the liquid ejection nozzle into the liquid injection space, wherein the electro-magnetic ejection valve is configured to eject liquid ejected from the ejection hole in a direction having a predetermined angle relative to a center axis of the hollow cylindrical hermetically sealed space, such that the distance of the liquid from the center axis increases accordingly as the distance from the ejection hole toward the liquid filling port increases.
By virtue of such a configuration, the liquid pressurized by the pressurizing means is ejected from the electromagnetic ejection valve into the injection device, and then the liquid is injected from the liquid ejection nozzle with being atomized by means of volume change of the chamber in the injection device.
In this case, the size of the atomized droplet varies depending on physical properties, such as a pressure to be applied to the liquid, an amplitude and/or a frequency of the vibration caused by the piezoelectric/electrostrictive element, the shape and/or dimension of a flow path, and the viscosity/surface tension of the liquid. However, if the period of vibration applied to the liquid is smaller than the time required for the liquid, in the vicinity of the end portion of the liquid ejection nozzle (the opening exposed to the liquid injection space), to travel by the length equivalent to the diameter of the end portion of the liquid ejection nozzle, the size of the droplet to be ejected is almost less than the diameter of the end portion of the liquid ejection nozzle. Therefore, for example, if the diameter of the end portion (opening) of the liquid ejection nozzle exposed to the liquid injection space is designed to be less than tens of &mgr;m's, the liquid injection apparatus will be able to inject droplets of liquid which are atomized (formed) into extremely uniform small pieces, and, for example, if the apparatus is used as a fuel injection apparatus for an internal-combustion engine, the fuel consumption of the internal-combustion engine can be improved and toxic emission can be reduced, as the apparatus can atomize (form) the injecting fuel into droplets of liquid having an appropriate diameter.
Hirota Toshikazu
Ohnishi Takao
Burr & Brown
Ganey Steven J.
NGK Insulators Ltd.
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