Patent ID: 6405720
Filing Date: 2002-06-18
Classification: F02B,F02D,F02M,Y02T

Abstract:
A method of producing near-zero NOx and near-zero CO emissions in exhaust gas from an internal combustion engine using a gaseous fuel wherein the exhaust gas includes water vapor, the method comprising the steps of:(a) providing an internal combustion engine having an intake for fuel and having exhaust gas; (b) providing a gaseous fuel comprised of natural gas and hydrogen sufficient to prevent said engine from misfiring during operation and adding said gaseous fuel to said engine; (c) separating the exhaust gas from the internal combustion engine into first and second portions, wherein the first portion comprises 30 to 50% of the exhaust gas; (d) cooling the first portion of the exhaust gas to condense at least a portion of the water vapor; (e) separating the condensed water from the first portion of the exhaust gas; (f) discharging a second portion of the exhaust gas to the atmosphere; (g) operating said engine to combust a charge of said gaseous fuel and air in an equivalence ratio in the range of 0.6 to 0.45, said charge diluted with said first portion of exhaust gas, said operating being carried out: (i) to produce not greater than 10 ppm NOx emissions in said exhaust gas emitted from said engine; and (ii) under lean burn conditions to provide not less than 0.5% oxygen in said exhaust gas emitted from said engine; and (h) oxidizing CO in said second portion of the exhaust gas using an oxidizing catalyst to produce not greater than 10 ppm CO emission in said second portion of the exhaust gas discharged to the atmosphere.