PURPOSE: To make it possible to perform highly accurate detection regardless of burning conditions, by making exhaust gas reaching a diffused resistor flow through a reformed catalyst layer.
CONSTITUTION: Electrodes 3 are deposited and formed on the front and rear surfaces of a solid state electrolyte 4. One electrode 3 is in contact with exhaust gas through a diffused resistor 2. A reformed catalyst layer 1 is arranged on the side of the resistor 2. The exhaust gas 7 is flowed to the side of the resistor 2 through the catalyst layer 1. In the catalyst layer 1, an aluminum honeycomb is used as a support, and Ni and Fe2O3-CrO3 are supported as the catalyst components. The catalyst layer 1 is provided in the vicinity of the exhaust gas port of an engine and heated to about 500°C from the outside. The compositions of the exhaust gas 8 through the catalyst layer 1 are measured under the following three kinds of burning conditions: in the idling state after warming-up; in the idling state immediately after starting; at the number of rotations three times the idling after warming-up. As a result, the compositions of the exhaust gas 8 at a certain fuel-air ratio agree in any burning conditions of three kinds along the entire region from a lean to rich state. HC is not detected in any case.
NISHIMURA SHIGEOKI
SAITO YUKIO
KAWAGOE HIROSHI
MIYADERA HIROSHI
