Patent ID: 8075759
Filing Date: 2011-12-13
Classification: G01N

Abstract:
1. A method of determining a Lambda value of internal combustion engine exhaust gas with a wideband Lambda sensor, the method comprising: measuring a pumping current, wherein the pumping current is a function of oxygen concentration in the exhaust gas; calculating a first oxygen concentration when the pumping current is cathodic, corresponding to an air-fuel mixture in a lean condition, the first oxygen concentration calculated from the measured pumping current and an oxygen sensitivity parameter; otherwise, calculating a second oxygen concentration when the pumping current is anodic, corresponding to the air-fuel mixture in a rich condition, the second oxygen concentration calculated from a hydrogen sensitivity parameter, a carbon monoxide sensitivity parameter, a gas concentration ratio, the measured pumping current, and the oxygen sensitivity parameter utilizing an equation wherein I pMeasured is the measured pumping current, K is the gas concentration ratio, ε_O 2 is the oxygen sensitivity parameter, and ε_H 2 is the hydrogen sensitivity parameter; and determining the Lambda value from one of the first oxygen concentration and the second oxygen concentration; wherein the gas concentration ratio is a predetermined measurement of gas concentration proportions in the internal combustion engine comprising a ratio of hydrogen concentration to carbon monoxide concentration.