Catalytic adsorption and oxidation based carbon monoxide sensor and detection method

A method of detecting a presence of carbon monoxide in a gas comprising the following steps:

• exposing a catalyst dispersed onto a metal oxide layer to the gas that comprises carbon monoxide, the catalyst capable of adsorbing carbon monoxide onto the metal oxide layer;
• adsorbing at least a portion of the carbon monoxide in the gas onto the metal oxide layer;
• heating the catalyst and metal oxide layer to a first temperature that is at least as high as the oxidation temperature of carbon monoxide adsorbed onto the first metal oxide layer, thereby resulting in an exothermic oxidation of said carbon monoxide adsorbed onto the metal oxide layer and an increase in temperature of the metal oxide layer;
• using the temperature increase of the metal oxide layer, thereby indicating the presence of carbon monoxide in the gas.

A carbon monoxide sensor comprising:

• a sensing element;
• a flow sensor for sensing a flow rate of gas towards the sensing element;
• a filter disposed upstream of the flow rate sensor so that the flow rate sensor is disposed between the filter and the sensing element;
• a signal processing module in communication with the flow sensor and the sensing element;
• the sensing element comprising a catalyst dispersed over a first metal oxide layer, the catalyst capable of adsorbing carbon monoxide onto the first metal oxide layer, the sensing element further comprising a second metal oxide layer disposed on top of the catalyst and first oxide layer, the sensing element further comprising a heater;
• the flow sensor sending signals indicative of the flow rate to the processing module;
• the sensing element sending signals indicative of the temperature of the sensing element to the processing module;
• whereby, after carbon monoxide has been adsorbed onto the first metal oxide layer, the heater heats the sensing element to a first temperature that is at least as high as the oxidation temperature of carbon monoxide adsorbed onto the first metal oxide layer, thereby resulting in an exothermic oxidation of said carbon monoxide adsorbed onto the first metal oxide layer and an increase in temperature of the sensing element to a second temperature.

A method of detecting a presence of carbon monoxide in an exhaust stream comprising the following steps:

• exposing a catalyst dispersed onto a metal oxide layer to the exhaust stream, the catalyst capable of adsorbing carbon monoxide onto the metal oxide layer;
• adsorbing at least a portion of the carbon monoxide in the exhaust stream onto the metal oxide layer;
• sensing a flow rate of the exhaust stream that engages the catalyst and metal oxide layer over a fixed time period;
• heating the metal oxide layer to a first temperature that is at least as high as the oxidation temperature of carbon monoxide adsorbed onto the metal oxide layer, thereby resulting in an exothermic oxidation of said carbon monoxide adsorbed onto the metal oxide layer and an increase in temperature of the metal oxide layer;
• using the temperature increase of the metal oxide layer, thereby indicating the presence of carbon monoxide in the exhaust stream;
• calculating a cumulative value for the carbon monoxide adsorbed onto the metal oxide layer from the increase in temperature of the metal oxide layer due to the exothermic oxidation of the carbon monoxide;
• calculating a volume of exhaust stream by multiplying the flow rate by the fixed time period;
• calculating a concentration of carbon monoxide in the exhaust stream as a function of the cumulative value and the volume.