US 4,380,984 AGranted

Electronic controlled carburetor

AssigneeNissan Motor Co., Ltd.

InventorsTadashi Nagai, Ken Nakamura, Yasuo Nakajima

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Abstract

An electronic controlled carburetor has an induction passage into which fuel is fed by a fuel metering system communicated with the atmosphere through main and auxiliary air bleed passages. The main and auxiliary air bleed passages have therein main and auxiliary solenoid valves, respectively, for altering the rate of air flow therethrough. A control circuit determines the duty ratio of a first pulse signal applied to the main solenoid valve in response to an air/fuel ratio indicative signal from an oxygen sensor. The control circuit determines the duty ratio of a second pulse signal applied to the auxiliary solenoid valve from the duty ratio of the first pulse signal so as to permit the main solenoid valve to operate around 50% duty ratio over all engine operating modes.

Claims14

Dependent claims

An electronic controlled carburetor for an internal combustion engine, comprising:

(a) an induction passage for supplying a combusible mixture to said engine;
(b) a source of fuel;
(c) fuel metering means communicating between said source of fuel and said induction passage, said fuel metering means communicated with the atmosphere through a main air bleed passage and also through an auxiliary air bleed passage;
(d) first and second solenoid valves provided in said main and auxiliary air bleed passages for varying the rates of air flow to said fuel metering means, respectively;
(e) engine exhaust gas analyzing means effective for sensing selected constituents of the exhaust gases of said engine and producing in response thereto an output signal;
and
(f) a control circuit responsive to the output signal of said engine exhaust gas analyzing means for operating said first and second solenoid valves, said control circuit comprising a first comparator for providing the difference between the output of said engine exhaust gas analyzing means and a predetermined reference value, an amplifier for providing a first signal proportional to the difference, a first integrator for providing a second signal resulting from integrating the difference, an adder for providing a third signal resulting from adding the first and second signals, a first pulse generator for providing a first drive pulse signal having a duty ratio dependent upon the third signal to said first solenoid valve, a second comparator for providing the deviation between the second signal and a predetermined reference value, a second integrator for providing a fourth signal resulting from integrating the deviation, and a second pulse generator for providing a second drive pulse signal having a duty ratio dependent upon the fourth signal to said second solenoid valve.

4 more elements

An electronic controlled carburetor for an internal combustion engine, comprising:

(a) an induction passage for supplying a combusible mixture to said engine;
(b) a source of fuel;
(c) main fuel metering means communicating between said source of fuel and said induction passage, said main fuel metering means communicated with the atmosphere through a main air bleed passage;
(d) idle fuel metering means communicating between said source of fuel and said induction passage, said idle fuel metering means communicated with the atmosphere through an idle air bleed passage;
(e) first and second solenoid valves provided in said main and idle air bleed passages for varying the rates of air flow therethrough, respectively;
(f) an auxiliary air passage communicating said main and idle fuel metering means with the atmosphere;
(g) an auxiliary solenoid valve provided in said auxiliary air passage for varying the rate of air flow therethrough;
(h) engine exhaust gas analyzing means effective for sensing selected constituents of the exhaust gases of said engine and producing in response thereto an output signal;
and
(i) a control circuit responsive to the output signal of said engine exhaust gas analyzing means for operating said first, second and auxiliary solenoid valves, said control circuit comprising a first comparator for providing the difference between the output of said engine exhaust gas analyzing means and a predetermined reference value, an amplifier for providing a first signal proportional to the difference, a first integrator for providing a second signal resulting from integrating the difference, an adder for providing a third signal resulting from adding the first and second signals, a first pulse generator for providing a first drive pulse signal having a duty ratio dependent upon the third signal to said first and second solenoid valves, a second comparator for providing the deviation between the second signal and a predetermined reference value, a second integrator for providing a fourth signal resulting from integrating the deviation, and a second pulse generator for providing a second drive pulse signal having a duty ratio dependent upon the fourth signal to said auxiliary solenoid valve.

7 more elements

Dependencies are inferred from the claim text.