Anomaly determination system and anomaly determination method

An anomaly determination system comprising:

• an inlet pressure sensor for detecting an inlet pressure of a pressure loss portion that is arranged in a fluid passage of a vehicle and causes pressure loss of fluid;
• an outlet pressure sensor for detecting an outlet pressure of the pressure loss portion;
• an outside pressure sensor for detecting an outside pressure, which is a pressure outside the fluid passage;
• and
• an anomaly determination section for determining an anomaly of the pressure loss portion, wherein
• the anomaly determination section is configured to:
• store a first pressure loss range indicative of pressure loss of the pressure loss portion in an anomalous state;
• determine whether a flow rate in the fluid passage is greater than or equal to a minimum flow rate at which the anomaly in the pressure loss portion is detectable;
• and
• determine that the pressure loss portion is anomalous if the following two conditions are both met:
• a difference between the inlet pressure and the outlet pressure, a difference between the outlet pressure and the outside pressure, and a difference between the outside pressure and the inlet pressure which differences are detected when the flow rate is less than the minimum flow rate are all included in an allowable range, and
• a pressure difference between the inlet pressure and the outlet pressure when the flow rate is greater than or equal to the minimum flow rate is included in the first pressure loss range.