Patent ID: 7922884

Claim:
A device for measuring pressure in a gas mixture, comprising: an amperometric sensor that operates according to a limiting current principle, the sensor including two first electrodes mounted on a solid electrolyte, a direct voltage being applied to the first electrodes, wherein one of the first electrodes is shielded by a diffusion barrier; a measuring element configured to measure the limiting current flowing via the first electrodes as a measure of the gas pressure; and an arrangement configured to fix, at least during a pressure measuring phase, a mole fraction of a gas component drawn upon for the pressure measurement upstream of the diffusion barrier to a constant 100%, wherein the arrangement includes a storage volume for the gas component, the storage volume be arranged in front of the diffusion barrier in the solid electrolyte, a diffusion path closing off the storage volume in a direction of the gas mixture, the arrangement further including two second electrodes situated at the solid electrolyte to pump the gas component all the way through the solid electrolyte into the storage volume, wherein the sensor includes a Nernst cell made up of a solid electrolyte and two second electrodes situated thereon, a first one of the second electrodes being a measuring electrode and being situated in a measuring chamber developed in the solid electrolyte, and a second one of the second electrodes being a reference electrode and being exposed to a pumped oxygen reference in a reference gas channel developed in the solid electrolyte; and a pump cell made up of a solid electrolyte and two pump electrodes situated thereon, an outer one of the pump electrodes situated thereon, an outer one of the pump electrodes being exposed to the exhaust gas and an inner one of the pump electrodes being situated in the measuring chamber; wherein the reference gas channel is provided with an opening that is exposed to the exhaust gas, and wherein in the reference gas channel between the reference electrode and the opening, the diffusion path and the storage volume are developed, and an outer one of the pump electrodes and the reference electrode being used as intervals for pumping oxygen and for measuring gas pressure by switching over their voltage potentials.