A method of determining a thermal state or a thermal state transition of a substance based on how much liquid phase is available is disclosed. The method includes: (a) determining a current thermal state of the substance when the internal combustion engine is switched on based on a tank temperature and on a time interval during which the engine is switched off; and (b) calculating a percentage of the liquid phase in case the thermal state is a mixture of solid phase and liquid phase based on a total mass of the substance in the tank, a heat amount supplied to the tank, a heat exchange of the tank with an external environment; and (c) detecting the thermal state transitions based on said tank temperature and its time derivative and on said percentage of the liquid phase.

A composite sensor for sensing gas and dust by using a single heat source, according to an embodiment of the present invention, can comprise: a base; a gas sensor module comprising a gas sensor and a first light source in a first space; a dust sensor module comprising a dust sensor, a lens, and a second light source in a second space; and a heat transfer wall for transferring heat generated by the first light source to the dust sensor module.

A composite sensor for sensing gas and dust by using a single heat source, according to an embodiment of the present invention, can comprise: a base; a gas sensor module comprising a gas sensor and a first light source in a first space; a dust sensor module comprising a dust sensor, a lens, and a second light source in a second space; and a heat transfer wall for transferring heat generated by the first light source to the dust sensor module.

Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

In a gas sensor diagnosis device, a temperature change part varies a temperature of a sensor element in an ammonia sensor at a first temperature which is outside of the predetermined activation temperature range. A zero-voltage shift detection part detects whether the mixed potential of the sensor element is not more than a predetermined output threshold value after the temperature change part varies a temperature of the sensor element. A temperature acquisition part detects a zero-voltage shift temperature of the sensor element at which the zero-voltage shift detection part detects that the mixed potential of the sensor element drops below the predetermined output threshold value. The deterioration state detection part detects a deterioration state of the ammonia sensor based on the zero-voltage shift temperature of the sensor element detected by the temperature acquisition part.

In a gas sensor diagnosis device, a temperature change part varies a temperature of a sensor element in an ammonia sensor at a first temperature which is outside of the predetermined activation temperature range. A zero-voltage shift detection part detects whether the mixed potential of the sensor element is not more than a predetermined output threshold value after the temperature change part varies a temperature of the sensor element. A temperature acquisition part detects a zero-voltage shift temperature of the sensor element at which the zero-voltage shift detection part detects that the mixed potential of the sensor element drops below the predetermined output threshold value. The deterioration state detection part detects a deterioration state of the ammonia sensor based on the zero-voltage shift temperature of the sensor element detected by the temperature acquisition part.

A gas measuring device (100) and a gas measuring process measure a concentration of a combustible target gas (CH.sub.4). A detector (10), having a detector heating segment (20), oxidizes combustible target gas. A compensator (11) having a compensator heating segment (30) oxidizes less or no target gas. A temperature sensor (14) measures the ambient temperature. A first detection variable (U_B) depends on the detector temperature, a second detection variable (U11) depends on the compensator temperature. An evaluation unit (9) applies a first and a second functional relationship in order to determine, depending on the two detection variables (U_B, U11), both the target gas concentration and a further environmental condition, particularly the ambient humidity. The second functional relationship, a dependence between the further environmental condition on the one hand and the detection variables and the ambient temperature on the other hand, is valid if no target gas is present.

A gas measuring device (100) and a gas measuring process measure a concentration of a combustible target gas (CH.sub.4). A detector (10), having a detector heating segment (20), oxidizes combustible target gas. A compensator (11) having a compensator heating segment (30) oxidizes less or no target gas. A temperature sensor (14) measures the ambient temperature. A first detection variable (U_B) depends on the detector temperature, a second detection variable (U11) depends on the compensator temperature. An evaluation unit (9) applies a first and a second functional relationship in order to determine, depending on the two detection variables (U_B, U11), both the target gas concentration and a further environmental condition, particularly the ambient humidity. The second functional relationship, a dependence between the further environmental condition on the one hand and the detection variables and the ambient temperature on the other hand, is valid if no target gas is present.

A composite sensor for sensing gas and dust by using a single heat source, according to an embodiment of the present invention, can comprise: a base; a gas sensor module comprising a gas sensor and a first light source in a first space; a dust sensor module comprising a dust sensor, a lens, and a second light source in a second space; and a heat transfer wall for transferring heat generated by the first light source to the dust sensor module.