EFFECT OF AIR INJECTION INTO EXHAUST MANIFOLD TO SPECIFICATIONS, EMISSIONS AND EFFICIENCY OF THREE WAY CATALYST EQUIPPED IN MOTOBIKE ENGINE USING CABURATOR

Abstract

According to the ideal characteristics of the carburetor, most engines usually work in the mode of rich-mixture
(equivalence ratio λ is less than 1). Rich-mixture not only leads to high level of CO and HC emissions but also is one of the
factors limiting the ability to operate the Three Way Catalysts (TWC) on engines using carburetors (low emission
components conversion efficiency by the TWC). This paper presents the effect of air additions on the exhaust path to the
technical features, emissions and conversion efficiency of the TWC equipped on motorcycle engines using carburetors. The
results show that the proper addition of air to the exhaust path will not only help provide more oxygen for the oxidation
reactions, but also improve the oxidizing environment to increase the efficiency of handling CO and HC emission
components in the TWC. The results illustrate that with the amount of additional air on the exhaust path so that λ remains
equal to stoichiometric value, the engine economic-technical parameters have no significant changes while engine
emissions as well as the catalyst performance were significantly improved (conversion efficiency of CO increased by
39.54%, HC increased by 24.89%).