Abstract
During the last twenty years the number of patent publications in the field of the control of hydrocarbon compounds during the cold start period of a gasoline engine has strongly increased and seems now that the number of patents tends to increase during the following years. This fact has been related with increasingly stringent legislations all over the world which highlights the importance of developing efficient systems for the control of cold start hydrocarbon emissions. The technologies that show a higher number of patents are the hydrocarbon trap, the close-coupled catalyst and the electrically heated catalyst.
Keywords: Close-coupled catalyst, cold start emissions, electrically heated catalyst, hydrocarbon trap
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