Internal-combustion engines – Charge forming device – With fuel pump
Reexamination Certificate
2000-05-12
2001-09-25
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Charge forming device
With fuel pump
C417S045000
Reexamination Certificate
active
06293255
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a fuel injection system, and more particularly to an injection system, which provides improved injection volume and timing control.
BACKGROUND OF TE INVENTION
Recently a great deal of attention has been given to the level of emissions generated by internal combustion engines, as well as their efficiency. In order to increase the efficiency of these engines and reduce their harmful emissions, fuel injectors have been developed for metering the fuel supplied to the engine.
In general, these fuel injectors include a body having a solenoid operated flow valve. Biasing means such as a spring apply a force to a body of the valve for closing the valve, while when activated the solenoid overcomes the spring force to open the valve.
Fuel is supplied under high pressure to the fuel injector, such as with a high pressure pump. When the valve of the injector is opened, the fuel flows therethrough to the engine.
A problem associated with this valve is that the range of opening time of the valve of the injector cannot be controlled with infinite precision. In particular, the momentum of the mass of the valve body, spring and the like serve to limit the rate of speed with which the valve may be opened and reclose. A typical minimum working during may be about 1 Ms.
At this long minimum working duration, maximum fuel delivery benefits are generally only achieved when the engine speed is less than about 1000 rpm. When the engine speed is above this speed, as is very common with today's engines, the duration during which fuel is delivered to the engine during a given cycle is longer than the desired fuel injection duration.
One manner to decrease the working duration in this type of valve is to decrease the pressure at which the fuel is delivered. This permits the valve to close somewhat faster. On the other hand, this solution has the attenuated problem that the low fuel pressure may not permit atomization of the fuel, which is injected, reducing the burn efficiency and thus overall engine efficiency and emissions benefits.
It is an object of the present invention to provide a fuel injection system, which provides for a large dynamic range of injection time, permitting the fuel injection time to be varied over a wide time duration. It is a further object of the present invention to provide a fuel injection system, which permits accurate control of the volume of fuel delivered, and the time of delivery thereof.
SUMMARY OF THE INVENTION
The present invention is an injection system including an injection device. The injection device includes a pumping chamber and an electrically operated device associated with the pumping chamber which, when energized, is capable of providing a rapid increase in localized fluid pressure in said pumping chamber without reciprocating a piston in a cylinder bore. A discharge port associated with the pumping chamber permits discharging of fluid displaced by the localized pressure increase.
The injection system includes means for providing an energizing voltage to the electrically operated device, and control means for changing at least one characteristic of the energizing voltage selected from the group consisting of: the peak energizing voltage, the rate at which said energizing voltage increases, the rate at which said energizing voltage decreases, the duration of energization, and the frequency of energization.
In the preferred embodiment, the injection device is a fuel injection device for delivering fuel to an internal combustion engine. In this arrangement, control means is arranged to control the at least one characteristic of the energizing voltage dependent upon the magnitude or rate of change of the engine load.
In accordance with the present mvention, an injection device is provided which permits accurate control of the volume and time of liquid injected.
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Electrostrictive Materials, http://www.luec.leeds.ac.uk/ElectrostrictiveMaterials.htm.
Kageyama Hidetoshi
Kaku Junichi
Otome Kimitake
Beutler Ernest A.
Gimie Mahmoud
Yamaha Hatsudoki Kabushiki Kaisha
Yuen Henry C.
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