Exhaust system Law in the United States and other countries to not have a catalytic converter. Converters may not be removed from a vehicle that is used only for "off-road" driving in the United States. The main purpose of a catalytic converter on an automobile is to reduce harmful emissions of hydrocarbons, carbon monoxide and nitrogen oxides into the atmosphere. They work by transforming the polluted exhaust components into water and carbon dioxide. Cat-back (also cat back and catback) refers to the portion of the exhaust system from the outlet of the catalytic converter to the final vent to open air. This
Steam locomotive exhaust system reason the blower is often turned on in these situations, to counteract the compression effect. The aim of exhaust system development is to obtain maximum smokebox vacuum with minimum back pressure on the pistons. Little development of the basic principles of smokebox design took place until 1908, when the first comprehensive examination of steam-raising performance was carried out by W.F.M. Goss of Purdue University. These principles were adopted on the Great Western Railway by Churchward. Andre Chapelon made a significant improvement with his Kylchap exhaust which incorporated a "Kyala spreader" (second stage nozzle) and third stage cowl between the blastpipe