Fuel injection apparatus

Claim 1

In a fuel injection apparatus for the continuous injection of fuel into the suction tube of an internal combustion engine, said suction tube containing an arbitrarily operable butterfly valve, said apparatus being of the known type that has (a) an air sensor disposed in said suction tube spaced from said butterfly valve, said air sensor being deflected by the flow of intake air as a function of the intake air quantities, (b) means generating a return force affecting said air sensor and opposing the deflecting force of the air flow, said return force being independent from the deflected position of said air sensor, (c) a fuel metering and distributor valve having a movable valve member operatively connected to said air sensor to be displaced thereby to an extent proportionate to the deflection of said air sensor for maintaining constant the fuel-to-air ratio for any given return force, (d) means for applying hydraulic pressure to said movable valve member, said hydraulic pressure forming at least one part of said return force, (e) an electromagnet associated with said means generating said return force and (f) means for varying said return force as a function of the intensity of the energizing current flowing through said electromagnet, the improvement comprising means for varying the intensity of said energizing current as a function of the oxygen content of the exhaust gas for limiting the maximum concentration of pollutants therein, said last-named means including: A. an electric circuit for supplying said energizing current, B. a transistor connected in said circuit and having a base, C. a switch connected in said circuit to affect, dependent on its condition, the base current of said transistor, D. an oxygen sonde connected in said circuit and having 1. a first member exposed to said exhaust gas, 2. a second member spaced from said first member and exposed to a reference gas, 3. a solid electrolyte disposed in the space defined between said first and second members, E. means connecting said arbitrarily operable butterfly valve to said switch for actuating the latter when said butterfly valve assumes its full load position to vary said base current and to alter said energizing current for setting a richer air-fuel mixture, and F. means connected in said circuit, said last-named means varying said energizing current flowing in said circuit as a function of the potential difference between said first and second members.