A leakage diagnostic device diagnoses leakage of evaporated fuel in an evaporative fuel treatment device. The evaporative fuel treatment device purges evaporated fuel, which is generated in a fuel tank and adsorbed on a canister, to an intake passage. The leakage diagnostic device includes a vent valve that blocks a first atmospheric passage, which connects the canister with an atmospheric opening, and a pump that pressurizes and depressurizes a second atmospheric passage, which is a bypass passage of the first atmospheric passage. The malfunction diagnostic device diagnoses malfunction of the leakage diagnostic device based on an output value of a pressure sensor that detects pressure in a passage connected to the canister.

Systems, methods, and a computer readable medium are provided for monitoring and detecting a gas emission. Sensor data including gas concentration and wind data associated with a gas emission from an emission source is received from Near-Field and Far-Field sensors configured within a gas production and distribution environment. The sensor data can be provided as inputs to a Near-Field dispersion model to determine an emission rate associated with the gas emission and one or more source locations associated with the gas emission. The emission rate can be included in emission data and provided for output. Related apparatus, systems, techniques, and articles are also described.

Methods and systems are provided for estimating fuel volatility. During a vehicle-off condition following a refueling event, fuel volatility may be estimated by operating a fuel pump of a fuel system immediately after the refueling event while a fuel tank temperature is stable. Based on estimated fuel volatility, fuel injection amount and leak test thresholds may be adjusted.

Methods and systems are provided for regulating evaporative emissions from a fuel system. In one example, a method may comprise spinning an engine unfueled responsive to a hydrocarbon concentration at a fresh air end of a fuel vapor canister increasing above a first threshold. The method may comprise spinning the engine to pull hydrocarbons away until a hydrocarbon concentration at a purge end of the fuel vapor canister, opposite the fresh air end, increases above a second threshold.

Methods and systems are provided for indicating a restriction in a fuel system vapor recovery line. Responsive to such an indication, methods and systems are provided for taking mitigating actions such that an entirety of a vehicle fuel system and evaporative emissions system, including a fuel filler system, may be diagnosed as to a presence or absence of undesired evaporative emissions, even with the restriction in the vapor recovery line present. In this way, undesired evaporative emissions may be reduced or avoided, completion rates for such tests may be increased, and customer satisfaction may be improved.

Methods and systems are provided for the integration of a fuel level sensor and a fuel pressure sensor in a fuel tank within a fuel system. In one example, an integrated fuel pressure and fuel level sensor for a fuel tank may include a float arm of the fuel sensor coupled to a floating body and a pressure sensor (e.g., a fuel tank pressure transducer) coupled to the floating body, the integrated fuel pressure and fuel level sensor adapted to simultaneously measure fuel level and fuel vapor pressure of the fuel tank.

Methods and systems are provided for conducting a diagnostic routine of the fuel vapor system using pressure generated by raising or lowering a vehicle body element such as a hood or a trunk. In one example, by utilizing lift gate cylinders coupled to the hood or trunk, during raising a hood or trunk, the fuel vapor system may be evacuated and during lowering the hood or trunk, the fuel vapor system may be pressurized. A change in vacuum or higher pressure in the fuel vapor system may be monitored over a time period to detect any undesirable evaporative emissions from the fuel vapor system.

A method for detecting leakage of a high pressure fuel pump of a vehicle includes: turning off starting of an engine; after the starting of the engine is turned off, determining whether restarting of the engine occurs by a fuel rail pressure condition in which internal fuel pressure of a fuel rail connected between the high pressure fuel pump and an injector of the engine is less than or equal to a reference pressure; when the restarting of the engine occurs by the fuel rail pressure condition, determining whether a reference pressure reach time of the internal fuel pressure of the fuel rail is less than or equal to a reference time; and when the reference pressure reach time of the internal fuel pressure of the fuel rail is less than or equal to the reference time, storing a number of times of restarting of the engine.

A diagnostic method and system includes a control valve configured to control an amount of air drawn into an evaporative emissions (EVAP) system through an air filter and a vapor canister, and a pressure sensor configured to measure pressure in the EVAP system. The system also includes a controller configured to detect an engine idle-to-off transition and, in response to detecting the engine idle-to-off transition: receive a first pressure from the pressure sensor, fully open a purge valve connected between the vapor canister and an intake port of an engine, fully close the control valve, monitor one or more second pressures received from the pressure sensor, and detect a malfunction of the EVAP system based on the first pressure, at least one of the one or more second pressures, and a diagnostic threshold.

An evaporative fuel processing device for determining a leak of an evaporation piping system also determined pump abnormality by including a pump, a pressure sensor and an abnormality determiner, i.e., by pressuring/de-pressuring the system to a positive/negative value against an atmospheric pressure for leak determination, by detecting a pressure of the system, and by determining a leak hole in a normal leak determination mode based on an absolute value of the detected pressure reaching or not reaching a target value after pump operation and based on an assumption that the pump is normal. Specifically, after lapse of a determination time from a pump stop, the absolute value equal to or less than a normal leak determination threshold value is determined that a leak hole is present in the system. Further, the absolute value not reaching the target value even after pump operation triggers a pump abnormality determination mode.