Importance

Loading Importance Indicators...

Abstract

A method for controlling exhaust gas of an internal combustion engine includes controlling operation of the engine to fluctuate a lambda value of a raw exhaust gas at the lambda probe, exhibiting two-step action and disposed upstream of a three-way catalytic converter located in an exhaust tract, about a predetermined mean value. In a trimming controller, a concentration of an exhaust gas component downstream of the converter is measured with an amperometric-measuring sensor made from a solid-state electrolyte. In the sensor's first measuring cell, an oxygen concentration is measured through a first Nernst voltage between a first electrode and a reference electrode exposed to ambient air, and is controlled by a first oxygen-ion pumping current between the first electrode and an outer electrode of the sensor. In the second measuring cell of the sensor, the oxygen concentration is measured through a second Nernst voltage between the second and reference electrodes. A voltage is tapped between the outer and reference electrodes in conjunction with a series connection of the first and second measuring cells, and the voltage is used as a signal, dependent on the oxygen concentration and indicating two-step action, for trimming control. The predetermined mean values are corrected in dependence on the measured concentration of the exhaust gas component downstream of the converter. Preferably, the sensor is a NO.sub.x -measuring sensor, and, in its second measuring cell, the oxygen concentration in the second measuring cell is controlled through a second oxygen-ion pumping current.

Loading the Abstract Image...

First Claim