Dual sensor closed loop fuel control system having signal transfer between sensors during warmup

摘要

A closed loop fuel control system for an internal combustion engine having a catalytic converter in its exhaust system and a pair of zirconia sensors for generating respective signals indicative of the air-fuel ratio in the gases upstream and downstream of the catalytic converter. These sensors are used in the control system to control the rate of flow of fuel or air to the engine in response to the sensor signals to maintain a constant stoichiometric air-fuel ratio in the exhaust system for maximum catalytic converter efficiency in simultaneous oxidation and reduction. A circuit is described for imposing the output of the zirconia sensor upstream from the catalytic converter across the zirconia sensor downstream of the catalytic converter until the zirconia sensor downstream of the catalytic converter reaches its operating temperature.