Fuel system leakage anomaly detection device and fuel system leakage anomaly detection method for internal combustion engine

An anomaly detection method for an internal combustion engine, comprising, with a control circuit:

• filling a first fuel system with gaseous fuel;
• filling a second fuel system with gaseous fuel, wherein
• the internal combustion engine includes a fuel supply device,
• the fuel supply device includes a tank that stores gaseous fuel, a fuel injection valve that supplies fuel to a cylinder, a fuel passage that supplies the gaseous fuel in the tank to the fuel injection valve, a first shutoff valve disposed downstream of the tank in the fuel passage, a pressure reducing valve disposed downstream of the first shutoff valve in the fuel passage, a second shutoff valve disposed downstream of the pressure reducing valve in the fuel passage, a first pressure sensor disposed in the first fuel system, and a second pressure sensor disposed in the second fuel system,
• the first fuel system is a fuel system between the first shutoff valve and the second shutoff valve, and
• the second fuel system is a fuel system between the second shutoff valve and the fuel injection valve;
• determining a first magnitude relationship in a state in which the first fuel system is filled with gaseous fuel, the first magnitude relationship being a magnitude relationship between a detection value of the first pressure sensor and a predetermined first threshold value;
• determining a second magnitude relationship in a state in which the second fuel system is filled with gaseous fuel, the second magnitude relationship being a magnitude relationship between a detection value of the second pressure sensor and a predetermined second threshold value;
• and
• determining a leakage anomaly in the first fuel system or the second fuel system based on the determination of the first magnitude relationship or the determination of the second magnitude relationship.

A non-transitory computer-readable storage medium storing a program for causing a processer to perform an anomaly detection process for an internal combustion engine, the anomaly detection process comprising:

• filling a first fuel system with gaseous fuel;
• filling a second fuel system with gaseous fuel, wherein
• the internal combustion engine includes a fuel supply device,
• the fuel supply device includes a tank that stores gaseous fuel, a fuel injection valve that supplies fuel to a cylinder, a fuel passage that supplies the gaseous fuel in the tank to the fuel injection valve, a first shutoff valve disposed downstream of the tank in the fuel passage, a pressure reducing valve disposed downstream of the first shutoff valve in the fuel passage, a second shutoff valve disposed downstream of the pressure reducing valve in the fuel passage, a first pressure sensor disposed in the first fuel system, and a second pressure sensor disposed in the second fuel system,
• the first fuel system is a fuel system between the first shutoff valve and the second shutoff valve, and
• the second fuel system is a fuel system between the second shutoff valve and the fuel injection valve;
• determining a first magnitude relationship in a state in which the first fuel system is filled with gaseous fuel, the first magnitude relationship being a magnitude relationship between a detection value of the first pressure sensor and a predetermined first threshold value;
• determining a second magnitude relationship in a state in which the second fuel system is filled with gaseous fuel, the second magnitude relationship being a magnitude relationship between a detection value of the second pressure sensor and a predetermined second threshold value;
• and
• determining a leakage anomaly in the first fuel system or the second fuel system based on the determination of the first magnitude relationship or the determination of the second magnitude relationship.