Denso Corporation

Yusuke Kawamoto

Ryozo Kayama

Tadakatsu Koyabu

Takehito Kimata

Yuki Murayama

Toru Katafuchi

Yu Murata

Akari Hasegawa

Kazunari Azuma

Tomonori Ezaki

A gas sensor includes a measurement chamber, a reference gas chamber, a first cell that includes a first electrode in the measurement chamber and a second electrode in the reference gas chamber, and a second cell that includes a third electrode in the measurement chamber and a fourth electrode in the reference gas chamber. The gas sensor detects a first current that flows through the first cell, detects a second current that flows through the second cell, calculates a concentration of a specific gas component based on a detected value of the second current, determines whether a change has occurred in an oxygen concentration in the reference gas chamber based on a detected value of the first current, and corrects the detected value of the second current when the gas sensor determines that a change has occurred in the oxygen concentration in the reference gas chamber.

Gas sensor

A gas sensor includes a measurement chamber, a reference gas chamber, a first cell, and a second cell. The first cell includes a first electrode in the measurement chamber and a second electrode in the reference gas chamber. The second cell includes a third electrode in the measurement chamber and a fourth electrode in the reference gas chamber. A gas sensor detects a first current that flows between the first electrode and the second electrode, detects a second current that flows between the third electrode and the fourth electrode, calculates a concentration of a specific gas component based on a detected value of the second current, estimates a change amount of oxygen concentration in the reference gas chamber based on a detected value of the first current, and corrects the detected value of the second current based on an estimated value of the change amount of the oxygen concentration.

Each of SCUs to includes: a voltage switching unit that performs a first voltage switching to increase an oxygen concentration in a gas chamber and a second voltage switching to decrease the oxygen concentration in the gas chamber after the execution of the first voltage switching; an output change calculation unit that calculates an output change parameter indicating a change in output of the sensor cell according to the voltage switching; a concentration difference calculation unit that calculates a concentration difference parameter indicating a concentration difference in the oxygen concentration or in the concentration of the specific gas in the detection target gas between before the first voltage switching and after the second voltage switching; and a deterioration determination unit that determines a deterioration state of the sensor cell based on the output change parameter and the concentration difference parameter.

Gas sensor control device

An SCU as a control device for the gas sensor (first and second NOx sensors) includes an applied voltage switching unit for switching an applied voltage of a pump cell when a deterioration detecting function is performed, and a deterioration rate calculation unit for calculating a deterioration rate of a sensor cell based on a slope during a transient change in an output of the sensor cell according to a switching of the applied voltage by the applied voltage switching unit.

Growing community of inventors

Kariya, Japan

Yusuke Kawamoto