Measurement and control of exhaust gas recirculation with an oxygen pumping device

摘要

An electrochemical device and method measures the percentage of exhaust gas in the intake air/exhaust gas mixture going to the cylinders of an internal combustion engine. Two electrochemical pump cells and a support structure form a restricted volume in communication through an aperture to an ambient of intake air and exhaust gas mixture. Constant current is passed through a first pump cell to cause a portion of oxygen molecules inside the restricted volume to be pumped out. A constant voltage across the second pump cell causes substantially all the remaining O2 molecules inside the restricted volume to be pumped out. Current flowing in the second pump cell is measured, the current being proportional to the percentage of O2 inside the restricted volume and hence proportional to the percentage of O2 in the intake air and exhaust gas mixture, which is a measure of % EGR.