Method and apparatus to control the level of the air-to-fuel weight ratio in an internal combustion engine

摘要

A method and apparatus to control the level of the air-to-fuel weight ratio in an internal combustion engine includes taking from the engine a sample stream of exhaust gas which is small enough not to effect significantly the composition of the engine inlet mixture and then equilibrating the sample stream gas by reacting together the therein contained oxygen and any unburnt combustibles to produce an equilibrated gas. An untreated sample of equilibrated gas and a sample treated by addition of combustible are then provided and the untreated sample and treated sample are passed separately in time through a reaction zone maintained in conditions effective to cause mutual reactions of the added combustible and oxygen. The reaction zone contains a resistance wire acting as a catalyst wherein the reaction takes place in the immediate vicinity of a temperature sensor. The temperatures attained respectively by the untreated sample and the treated sample are then measured electrically in the reaction zone and the electrical signals are stored and compared so as to obtain a difference signal upon comparison. The difference signal is then fed to a servo mechanism actuating a gasoline feed valve in the inlet of the engine whereby the air-to-fuel weight ratio is controlled.