Electronic gas concentration control system

摘要

An electronic concentration control system in which a first exhaust gas composition sensor (16) located in an exhaust pipe (9) downstream from a catalytic converter (11) is connected to an input to a P.I. circuit (28) which generates a control output signal (K02) comprising a succession of opposing triangular ramps. The system includes a second exhaust gas composition sensor (14) located in the exhaust pipe (9) upstream from the catalytic converter (11) generating a signal which is fed to a proportional integral circuit (30) whose integrating and multiplying coefficients (Ki,Kp) are altered on the basis of the control signal (K02). The system includes a diagnostic circuit (50) which checks the efficiency of the first and second sensors (16, 14). <MATH> <MATH>