Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
266 words
In an air-fuel ratio control system for an internal combustion engine having an intake passage and an exhaust passage, air-fuel mixture supply means for supplying the air-fuel mixture to the engine, on-off type electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, the improvement comprising dither signal generating circuit means for producing a periodical dither signal having a waveform, a shift control circuit means for shifting the level of the center of said dither signal, driving circuit means operatively connected to said shift control circuit means for producing a driving output according to said dither signal and for driving said on-off type electromagnetic valve means, detecting means for detecting the concentration of oxygen in exhaust gases passing through said exhaust passage, a memory circuit means for memorizing a peak level of output of said detecting means and for producing an output according to the memorized peak level, first circuit means being applied with outputs of said detecting means and of said memory circuit means for detecting deviation of the dither signal detected by said detecting means, decision circuit means responsive to outputs of said first circuit means for producing a decision output representing the direction and amount of deviation of the detected dither signal from a stoichiometric air-fuel ratio, second circuit means responsive to said decision output of said decision circuit means for controlling said shift control circuit means dependent on said decision output of said circuit means in such a manner that the deviation of said dither signal is corrected to the stoichiometric air-fuel ratio.
Claim 2
Dependent Claim
266 words
In an air-fuel ratio control system for an internal combustion engine having an intake passage and an exhaust passage, air-fuel mixture supply means for supplying the air-fuel mixture to the engine, on-off type electromagnetic valve means for correcting the air-fuel ratio of the air-fuel mixture supplied by said air-fuel mixture supply means, the improvement comprising dither signal generating circuit means for producing a periodical dither signal having a waveform, a shift control circuit means for shifting the level of the center of said dither signal, driving circuit means operatively connected to said shift control circuit means for producing a driving output according to said dither signal and for driving said on-off type electromagnetic valve means, detecting means for detecting the concentration of oxygen in exhaust gases passing through said exhaust passage, a memory circuit means for memorizing a peak level of output of said detecting means and for producing an output according to the memorized peak level, first circuit means being applied with outputs of said detecting means and of said memory circuit means for detecting deviation of the dither signal detected by said detecting means, decision circuit means responsive to outputs of said first circuit means for producing a decision output representing the direction and amount of deviation of the detected dither signal from a stoichiometric air-fuel ratio, second circuit means responsive to said decision output of said decision circuit means for controlling said shift control circuit means dependent on said decision output of said circuit means in such a manner that the deviation of said dither signal is corrected to the stoichiometric air-fuel ratio.
Claim 3
Dependent Claim
52 words
The system as set forth in claim 1, wherein said second circuit means is for producing an output signal for deciding direction and amount of the shifting of said dither signal by the shift control circuit means such that the deviation of said dither signal is corrected to the stoichiometric air-fuel ratio.
Claim 4
Dependent Claim
20 words
The system as set forth in claim 1, wherein said first circuit means comprises a plurality of level detecting circuits.
Claim 5
Dependent Claim
71 words
The system as set forth in claim 3, wherein each of said plurality of level detecting circuits constitutes means for detecting deviation of the dither signal detected by said detecting means with respect to a different detecting level with respect to said memorized peak level from the detecting level of the others of said plurality of level detecting circuits and for comparing said detected dither signal with said detecting level, respectively.
Claim 6
Dependent Claim
62 words
The system as set forth in claim 4, wherein said decision circuit means is responsive to various combinations of the outputs of said level detecting circuits for producing said decision output respectively dependent on said various combinations of the outputs of said level detecting circuits representing the direction and amount of deviation of the detected dither signal from the stoichiometric air-fuel ratio.