Closed-Loop Exhaust Emission Control System with Electronic Fuel Injection

The Federal Standards pertaining to the exhaust emission control of the 1976 model year automobiles presumably demand the catalytic conversion of the pollutants involved. Provided the air-fuel ratio is maintained at a stoichiometric value, some problems (for instance, fuel economy) can be solved. A closed-loop system was developed, consisting of an electronic fuel injection system and a special oxygen sensor, called the λ-sensor, in the exhaust manifold.

First results on vehicles indicate that this control system offers an promising solution to the reduction of harmful contaminants. The closed-loop system can be used with a three-way catalytic converter or with a dual-bed system. It has not yet been investigated whether the durability of the two systems is adequate, apart from the general problems of the durability of each catalyst.