Patent ID: 6301881
Filing Date: 2001-10-16
Classification: F01N,Y02T

Abstract:
A method comprising the steps of:sensing at least one parameter value as a function of time of at least one fluctuating parameter in a gaseous stream, said gaseous stream having a frequency generated, at least in part, by an ECU controlling the pistons of an internal combustion engine cyclically producing said gaseous stream, said gaseous stream including as constituents thereof, at least oxygen, hydrocarbons and nitrogen oxides, and wherein the at least one fluctuating parameter comprises the concentration of one of said constituent gases;determining at least one frequency parameter in the frequency domain as a function of said at least one parameter value and said frequency, and a control value based on said frequency parameter; andgenerating a control signal based on the control value correlated to the concentration of said constituent gas selected as said fluctuating parameter.