Regulator for air=fuel mixt. for IC engine - has two oxygen@ sensors in exhaust, one either side of catalytic converter, feeding ECU controlling injectors

摘要

A regulator for the air-fuel ratio of an IC engine uses an oxygen sensor on either side of the catalytic converter in the exhaust system. A comparison of the two measurements is used to maintain the air-fuel ratio at the injectors (8) at a particular value. The regulator is an electronic control unit (ECU) with two stages (40A, 40B). The first stage has a differential amplifier with the output of the first sensor processed against a reference value. The second stage creates this reference value by differencing the output of the second sensor against another reference value. The output from the first differential amplifier is extended through a PI controller to the injectors. ADVANTAGE - Improved exhaust emission.