Exhaust emission control filter and method of controlling exhaust emission

Abstract

Carbon-containing particulates like soot included in an exhaust gas of an internal combustion engine are collected by means of a heat-resistant filter medium. The filter medium dispersedly collects hydrocarbon compounds and the carbon-containing particulates included in the exhaust gas. Even when the exhaust gas has a lower temperature than the combustible temperature of the carbon-containing particulates, such dispersed collection ensures start of a preliminary oxidation reaction of the collected hydrocarbon compounds with oxygen included in the exhaust gas. The collected hydrocarbon compounds and the collected carbon-containing particulates are then subjected to combustion with the exhaust gas having a filter inflow temperature lower than the combustible temperature of the carbon-containing particulates by utilizing the reaction heat and active species produced by the reaction. This technique thus simply but securely regulates and reduces the carbon-containing particulates included in the exhaust gas.