Procedure for the determination of the Lambda values with a broadband Lambda probe

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
• I
• p
• -
• Alternative
• =
• -
• I
• pMeasured
• 2
• ⁢
• ⁢
• (
• K
• +
• 1
• )
• ·
• ɛ_O
• 2
• K
• ·
• ɛ_H
• 2
• ·
• ɛ_O
• 2
• ,
• wherein IpMeasured is the measured pumping current, K is the gas concentration ratio, ε_O2 is the oxygen sensitivity parameter, and ε_H2 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.