Liquid state detecting sensor
AssigneeNgk Spark Plug Co., Ltd.
InventorsTakeo Sasanuma, Yoshikuni Sato, Takashi Yamomoto, Hisashi Sasaki
Life of this patent
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Abstract
A liquid state detecting sensor includes: a state detecting element including a heating resistor; an energization unit; a first output acquiring unit; a reference acquiring unit; a first calculating unit; a state detecting unit; a second output acquiring unit; a second calculating unit; an excess-temperature-rise determining unit; and an energization terminating unit. The energization termination unit terminates energizing of the heating resistor by the energization unit before the end of a detection time period in response to a determination by the excessive-temperature-rise determining unit that an excessive temperature rise has occurred in the state detecting element.
Claims6
A liquid state detecting sensor comprising:
- a state detecting element comprising a heating resistor having a resistance value that changes in correspondence with a temperature thereof, the state detecting element being immersed in a liquid to be measured;
- an energization unit for energizing the heating resistor;
- a first output acquiring unit for acquiring a first output value which is outputted in correspondence with the resistance value of the heating resistor at the end of a detection time period measured from a start of the energizing of the heating resistor by the energization unit;
- a reference acquiring unit for acquiring a reference value which is outputted in correspondence with the resistance value of the heating resistor prior to the end of the detection time period;
- a first calculating unit for calculating a first calculated value using the first output value and the reference value;
- a state detecting unit for detecting a state of the liquid to be measured based on the first calculated value;
- a second output acquiring unit for acquiring a second output value corresponding to the resistance value of the heating resistor after acquiring the reference value and before acquiring the first output value;
- a second calculating unit for calculating a second calculated value using the second output value and the reference value;
- an excessive-temperature-rise determining unit for determining whether an excessive temperature rise has occurred in the state detecting element based on (i) the second calculated value, and (ii) an excessive-temperature-rise determining threshold value;
- and
- an energization terminating unit for terminating the energizing of the heating resistor by the energization unit before the end of the detection time period in response to a determination by the excessive-temperature-rise determining unit that an excessive temperature rise has occurred in the state detecting element.
Dependencies are inferred from the claim text.