In-vehicle abnormality detection device and in-vehicle abnormality detection method

An in-vehicle abnormality detection method comprising:

• detecting in-vehicle carbon dioxide concentration of a vehicle when in a parked state by a CO2 concentration sensor;
• estimating a change rate of the in-vehicle carbon dioxide concentration at an optional time point when in the parked state on a basis of detection signals of the CO2 concentration sensor at two different time points when in the parked state;
• estimating, on a basis of a detection signal of the CO2 concentration sensor at the optional time point, a time constant of concentration change of the in-vehicle carbon dioxide concentration, and the estimated change rate, the in-vehicle carbon dioxide concentration at a time point when a predetermined time according to the time constant has elapsed since the optional time point;
• and
• determining that there is a detection target organism present in the vehicle when the estimated in-vehicle carbon dioxide concentration is equal to or more than a threshold value set according to the detection target organism.

An in-vehicle abnormality detection device comprising:

• a CO2 concentration sensor configured to detect in-vehicle carbon dioxide concentration of a vehicle;
• a parked state detection unit configured to detect that the vehicle is in a parked state;
• a time constant storage unit configured to store a time constant τ of concentration change of the in-vehicle carbon dioxide concentration;
• a change rate estimation unit configured to, on a basis of detection signals C(t1) and C(t2) of the CO2 concentration sensor at two different time points t1 and t2 (provided that t2>t1) when the parked state is detected by the parked state detection unit, estimate a change rate dC(t)/dt of the in-vehicle carbon dioxide concentration at a time point t when the parked state is detected;
• a threshold value determination unit configured to determine a threshold value Vth on a basis of a detection signal C(t3) of the CO2 concentration sensor at a time point t3 when the parked state is detected by the parked state detection unit, the time constant τ stored in the time constant storage unit, and an outside-vehicle CO2 concentration Coutdoor;
• and
• an abnormality determination unit configured to determine whether there is a detection target organism present in the vehicle according to a result of a comparison between the change rate of the carbon dioxide concentration estimated by the change rate estimation unit and the threshold value Vth determined by the threshold value determination unit.

An in-vehicle abnormality detection method comprising:

• detecting in-vehicle carbon dioxide concentration of a vehicle when in a parked state by a CO2 concentration sensor;
• estimating a change rate of the in-vehicle carbon dioxide concentration at an optional time point when in the parked state on a basis of detection signals of the CO2 concentration sensor at two different time points when in the parked state;
• determining a threshold value Vth of the change rate of the in-vehicle carbon dioxide concentration on a basis of a detection signal of the CO2 concentration sensor at the optional time point, a time constant of concentration change of the in-vehicle carbon dioxide concentration, and an outside-vehicle CO2 concentration Coutdoor;
• and
• determining whether there is a detection target organism present in the vehicle by comparing the estimated change rate of the in-vehicle carbon dioxide concentration with the threshold value Vth.