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A fuel injection device comprising an injection unit having a back pressure chamber and a fuel chamber which are separated by a diaphragm. The fuel chamber has on its lower end a fuel nozzle. A needle, cooperating with the fuel nozzle, is connected to the diaphragm. A flow control valve is arranged

A fuel injection device comprising an injection unit having a back pressure chamber and a fuel chamber which are separated by a diaphragm. The fuel chamber has on its lower end a fuel nozzle. A needle, cooperating with the fuel nozzle, is connected to the diaphragm. A flow control valve is arranged in the fuel feed passage connecting the fuel chamber to the fuel feed pump. The amount of the fuel injected from the fuel nozzle is controlled by the flow control valve so as to be proportional to the amount of the air sucked in. One end of the back pressure chamber is connected, to the pressure reducing chamber of the pressure reducing valve via a restricted opening and, the other end is connected to the fuel tank via the fuel return passage. An electromagnetic valve is arranged in the fuel return passage. An oxygen concentration detector is arranged in the exhaust passage of an engine. The electromagnetic valve is controlled by the oxygen concentration detector for equalizing the air-fuel ratio of the mixture, fed into the cylinders of an engine, to the stoichiometric air-fuel ratio.

대표청구항 ▼

A fuel injection device of an internal combustion engine having an intake passage and an exhaust passage, said device comprising: a fuel reservoir; fuel feed means connected to said fuel reservoir and discharging fuel of a constant pressure; an injector unit having a fuel chamber, a back pressure ch

A fuel injection device of an internal combustion engine having an intake passage and an exhaust passage, said device comprising: a fuel reservoir; fuel feed means connected to said fuel reservoir and discharging fuel of a constant pressure; an injector unit having a fuel chamber, a back pressure chamber, a diaphragm separating said fuel chamber from said back pressure chamber, and a plunger operatively connected to said diaphragm, said fuel chamber having a fuel nozzle which opens into said intake passage and cooperates with said plunger for forming a mixture in said intake passage, said injector unit further comprising spring means for biasing said plunger towards said fuel nozzle for closing said fuel nozzle by said plunger when the engine is stopped; a fuel feed passage connecting said fuel feed means to said fuel chamber; flow control means arranged in said fuel feed passage for controlling the flow of a fuel to feed the fuel into said fuel chamber in an amount which is proportional to the amount of sucked air flowing within said intake passage; pressure reducing mean connected to said fuel feed means and having a pressure reducing chamber for maintaining a fuel within said pressure reducing chamber at a constant pressure which is smaller than the constant pressure of the fuel discharged from said fuel feed means, said pressure reducing chamber being connected to said fuel chamber via a restricted opening; a fuel return passage connecting said fuel chamber to said fuel reservoir; an oxygen concentration detector in said exhaust passage for alternately producing a low level signal and a high level signal, said low level signal representing an air-fuel ratio of said mixture that is larger than the stoichiometric air-fuel ratio, said high level signal representing an air-fuel ratio of said mixture that is less than the stoichiometric air-fuel ratio; control means for producing continuous output pulses having a constant period, but variable pulse widths which vary in response to said low level signal and said high level signal; and, valve means in said fuel return passage for controlling a flow area of said fuel return passage in response to the output pulses of said control means to reduce and increase the pressure in said back pressure chamber when said oxygen concentration detector produces said low level signal and said high level signal, respectively.