Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2003-02-26
2004-08-17
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S549000, C123S590000, C123S585000
Reexamination Certificate
active
06776142
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and method for supplying fuel in an internal combustion engine with a variable valve lifter, preferably usable in an automobile.
A prior art internal combustion engine as disclosed by JP-A-2002-97916 includes a variable valve lifter by which lifter a lifted distance and/or a lift timing of an air intake valve is adjusted in accordance with an operating condition of the engine so that a mileage under low-load operation and an output power under high-load operation are improved.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an apparatus and method for supplying fuel in an internal combustion engine with a variable valve lifter, by which apparatus and method unburned carbon hydride is restrained from being exhausted from the internal combustion engine.
An apparatus for supplying fuel in an internal combustion engine including a combustion chamber, an air intake valve for selectively allowing an air and the fuel through the air intake valve to flow into the combustion chamber, and a variable valve lifter for adjusting an opening degree of the air intake valve with respect to the combustion chamber at each of combustion cycles, according to the present invention, comprises a vaporizing speed adjuster for changing a vaporizing (vaporization or vaporized fuel increasing) speed of the supplied fuel in accordance with a control signal to adjust a degree of vaporization of the fuel passing the air intake valve, and a controller for generating the control signal for changing the degree of vaporization of the fuel in accordance with at least one of the opening degree of the air intake valve and a load to be borne by the internal combustion engine (that is, an output torque or power to be output by the internal combustion) engine to restrain the fuel of liquid state from existing in the combustion chamber.
Since the vaporizing (vaporization or vaporized fuel increasing) speed of the supplied fuel is changed to adjust the degree of vaporization (for example, mass flow rate % of the vaporized fuel with respect to the whole mass flow rate of the supplied fuel) of the fuel passing the air intake valve so that the fuel of liquid state is restrained from existing in the combustion chamber, unburned carbon hydride generated from the fuel of liquid state existing in the combustion chamber is restrained from being exhausted from the internal combustion engine without unnecessary energy consumption for vaporizing always the fuel and/or vaporizing the whole of the fuel.
A method for supplying fuel in an internal combustion engine including a combustion chamber, an air intake valve for selectively allowing an air and the fuel to flow through the air intake valve into the combustion chamber, and a variable valve lifter for adjusting an opening degree of the air intake valve with respect to the combustion chamber at each of combustion cycles, according to the present invention, comprises the steps of: generating a control signal for changing a degree of vaporization of the fuel passing the air intake valve in accordance with at least one of the opening degree of the air intake valve and a load (for example, an output torque or power) of the internal combustion engine to restrain the fuel of liquid state from existing in the combustion chamber, and changing a vaporizing (vaporization increasing) speed of the supplied fuel in accordance with the control signal to adjust the degree of vaporization of the fuel.
Since the vaporizing (vaporization or vaporized fuel increasing) speed of the supplied fuel is changed to adjust the degree of vaporization (for example, mass flow rate % of the vaporized fuel with respect to the whole mass flow rate of the supplied fuel) of the fuel passing the air intake valve so that the fuel of liquid state is restrained from existing in the combustion chamber, unburned carbon hydride generated from the fuel of liquid state existing in the combustion chamber is restrained from being exhausted from the internal combustion engine without unnecessary energy consumption for vaporizing always the fuel and/or vaporizing the whole of the fuel.
If the control signal is generated in such a manner that the vaporizing speed of the fuel is increased in accordance with (for example, in proportion to) decrease of the opening degree of the air intake valve and/or the load, the unnecessary energy consumption is effectively decreased. If the control signal is generated in such a manner that the vaporizing speed of the fuel obtainable when the opening degree of the air intake valve and/or the load is not more than a predetermined value is higher than the vaporizing speed of the fuel obtainable when the opening degree of the air intake valve and/or the load is more than the predetermined value, an adjustment of the vaporizing speed of the fuel is easily performed by only switching on and off the acceleration of the vaporization of the fuel.
The vaporizing speed adjuster may include a heater to heat the supplied fuel so that the vaporization of the fuel is accelerated by thermal energy to increase the degree of vaporization of the fuel. The vaporizing speed of the supplied fuel may be changeable in accordance with a variation of the heating thermal energy quantity. The vaporizing speed adjuster may include an air injector to inject an air into the fuel so that the vaporization of the fuel is accelerated by collision between the fuel and the injected air (for forming fuel fine mist to decrease diameter of the mist particles so that a ratio of surface area of particle to mass of particle is increased to accelerate the vaporization of the fuel) to increase the degree of vaporization of the fuel. The vaporizing speed of the supplied fuel may be changeable in accordance with a mass flow rate of the injected air.
The vaporizing speed adjuster may include a fuel injector to change a timing of fuel injection with respect to a pressure in the combustion chamber in accordance with the control signal, and the control signal is generated in such a manner that the pressure in the combustion chamber obtainable when the fuel is injected by the fuel injector lowers in accordance with a decrease of the opening degree of the air intake valve and/or the load so that the vaporization of the fuel is accelerated by a difference in pressure across (between upstream and downstream sides of) the air intake valve (increasing in accordance with decrease of the pressure in the combustion chamber) to increase the degree of vaporization of the fuel by stirring a mixture of the air and fuel with a high velocity of the mixture over the air intake valve and/or collision between the air and fuel for forming the fine particle fuel mist. If the fuel is injected with the pressure in the combustion chamber less than a predetermined degree and is prevented from being injected with the pressure in the combustion chamber not less than the predetermined degree, the stirring of the mixture of the air and fuel with the high velocity of the mixture over the air intake valve and/or collision between the air and fuel for forming the fine particle fuel mist is securely performed, by keeping the difference in pressure across the air intake valve more than a desirable degree. It is preferable for keeping the difference in pressure across the air intake valve more than the desirable degree that a pressure at an upstream side of the air intake valve in a fuel flow direction is higher than the pressure in the combustion chamber when the pressure in the combustion chamber is less than the predetermined degree. If the fuel is injected with the pressure in the combustion chamber less than the predetermined degree and is prevented from being injected with the pressure in the combustion chamber not less than the predetermined degree when the opening degree of the air intake valve and/or the load is not more than a predetermined value, the fuel may be injected with the pressure in the combustion chamber not less than the predetermined degree when the
Ichihara Takanobu
Nogi Toshiharu
Saeki Hiroaki
Sukegawa Yoshihiro
Crowell & Moring LLP
Wolfe Willis R.
LandOfFree
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