Abstract: A method of measuring a rate of change of carbon dioxide concentration in recirculated air of an engine, is disclosed. The method includes installing a conductive sample tube into an engine's pre-combustion/air-mixing chamber, and installing a carbon dioxide sensor, remote from the chamber, to measure relative concentrations of carbon dioxide. The method may also be used to measure nitrogen oxide exhaust gas levels.

Abstract: A device for sensing a dangerous condition includes a sensor that provides a signal when a dangerous condition is sensed by the sensor. A power source is provided which is in communication with the sensor. The power source supplies the sensor with power. A trigger is provided which is in communication with the sensor. The trigger is activated by the signal to prevent the dangerous condition from producing a harmful effect. In one embodiment of the invention the power source is a thermoelectric power supply and the sensor is a self calibrating sensor.

Abstract: An economizer control for controlling air quality. The economizer control includes a sensor that senses characteristics of air, a damper located relative to the sensor so that the damper can control air flow of outside air and re-circulated air to the sensor, and a controller in communication with the sensor and the damper. The controller controls the opening and closing of the damper according to conditions sensed by the sensor.

Abstract: A method of measuring a rate of change of carbon dioxide concentration in recirculated air of an engine, is disclosed. The method includes installing a conductive sample tube into an engine's pre-combustion/air-mixing chamber, and installing a carbon dioxide sensor, remote from the chamber, to measure relative concentrations of carbon dioxide. The method may also be used to measure nitrogen oxide exhaust gas levels.

Abstract: A device for sensing a dangerous condition includes a sensor that provides a signal when a dangerous condition is sensed by the sensor. A power source is provided which is in communication with the sensor. The power source supplies the sensor with power. A trigger is provided which is in communication with the sensor. The trigger is activated by the signal to prevent the dangerous condition from producing a harmful effect. In one embodiment of the invention the power source is a thermoelectric power supply and the sensor is a self calibrating sensor.

Abstract: An automatic calibration mode for a carbon dioxide sensor is based on using a zero gas. The sensor is designed to recognize a distinctive rate of change pattern of carbon dioxide concentrations that would be indicative of a zero calibration routine. This approach can be used for other infrared sensors.

Abstract: A method of measuring a rate of change of carbon dioxide concentration in recirculated air of an engine, is disclosed. The method includes installing a conductive sample tube into an engine's pre-combustion/air-mixing chamber, and installing a carbon dioxide sensor, remote from the chamber, to measure relative concentrations of carbon dioxide. The method may also be used to measure nitrogen oxide exhaust gas levels.

Abstract: An automatic calibration mode for a carbon dioxide sensor is based on using a zero gas. The sensor is designed to recognize a distinctive rate of change pattern of carbon dioxide concentrations that would be indicative of a zero calibration routine. This approach can be used for other infrared sensors.

Abstract: A method of measuring a rate of change of carbon dioxide concentration in recirculated air of an engine, is disclosed. The method includes installing a conductive sample tube into an engine's pre-combustion/air-mixing chamber, and installing a carbon dioxide sensor, remote from the chamber, to measure relative concentrations of carbon dioxide. The method may also be used to measure nitrogen oxide exhaust gas levels.

Abstract: A method for determining the presence of an occupant in an enclosure space, particularly a trunk compartment, based on a rate of change of carbon dioxide concentration in the space/compartment, is disclosed. The primary sources taken into consideration are customary and non-customary leakages of carbon dioxide into the space to be measured. A warning/control logic is preferably configured to identify a rate of change of carbon dioxide that is likely when one or more humans occupy the space/compartment.

Abstract: A method for indicating a condition of oxygen depletion in a space, is disclosed. The method of measuring oxygen depletion is employed using the rate of change of carbon dioxide as a surrogate indicator of the amount of oxygen being depleted or displaced in the air. Displacement may be measured when the rate of change of carbon dioxide concentration falls within a rate of change range, or rises above or falls below a rate of change threshold level that indicates the displacement of oxygen.

Abstract: A method for detecting improper venting of a combustion appliance within an interior space relies upon a carbon dioxide detector to determine whether a preselected criterion indicative of improper venting is exceeded. The preselected criterion can be a threshold concentration of carbon dioxide or a threshold level of rate of rise of carbon dioxide concentration that is exceeded at a specified time or over a specified interval of time. The method can be used to detect leaks in a residential furnace, at very low levels, during start up of the furnace by measuring the preselected criterion in a heated air duct.