Methods and systems for diagnosing operation of an evaporative emissions system are described. The methods and systems may include increasing an amount of vacuum stored in an evaporative emissions system during discontinuously operating an engine in a boosted operating mode. Storing vacuum allows the evaporative emissions system to reach a desired vacuum level to verify absence of an evaporative emissions system breech.

A method and device for diagnosing a leak in an evaporation system and in a tank ventilation line of an internal combustion engine is disclosed. The method includes diagnosing the entire evaporation system using a fresh-air shut-off valve of the evaporation system and a pressure sensor system of the evaporation system. During the check on whether there is a leak in the evaporation system of the internal combustion engine, a separate check of different diagnosis regions of the evaporation system is undertaken, where one of these diagnosis regions is a tank region of the internal combustion engine and a further diagnosis region is a filter region of the internal combustion engine. During the diagnosis of the tank ventilation line, the flow through the tank ventilation line is checked.

Methods and systems for diagnosing operation of an evaporative emissions system are described. The methods and systems may include increasing an amount of vacuum stored in an evaporative emissions system during discontinuously operating an engine in a boosted operating mode. Storing vacuum allows the evaporative emissions system to reach a desired vacuum level to verify absence of an evaporative emissions system breech.

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 fuel tank isolation valve (FTIV) and methods of operation are provided. The FTIV includes first and second solenoid valves with the movable valve member of one of the solenoid valves seating against a movable valve member of the other one of the solenoid valves. One of the solenoid valves may be refueling valve allowing for evacuation of fuel vapor during refueling operations as well as to allow for purging high vapor pressure within the fuel tank. One of the solenoid valves may be a proportional valve used to control the flow of fuel vapor to an intake manifold of an operating internal combustion engine as well as to reduce a vacuum generated within the fuel tank.

Methods and systems are provided for a fuel system. In one example, a method may include cleaning an orifice of an ELCM. The cleaning includes adjusting a position of a valve in a passage to fluidly couple a reference orifice of the ELCM to an intake manifold.

An evaporative emissions (EVAP) control system for a vehicle includes a purge pump configured to pump fuel vapor to an engine of the vehicle via a vapor line and a purge valve. The system includes a hydrocarbon (HC) sensor disposed in the vapor line and configured to measure an amount of HC in the fuel vapor pumped by the purge pump to the engine via the vapor line. A controller is configured to: detect an imminent cold start of the engine and, in response to the detecting, perform the cold start of the engine by controlling at least one of the purge pump and the purge valve, based on the measured amount of HC, to deliver a desired amount of fuel vapor to the engine, which decreases HC emissions by 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.

A vehicle includes a fuel tank, a primary canister, a secondary canister, a first valve, a second valve, a third valve, a heater, and a controller. The primary and secondary canisters are in fluid communication with the fuel tank and are configured to receive and store evaporated fuel from the fuel tank. The first valve is disposed between the fuel tank and the primary canister. The second valve is disposed between the secondary canister and ambient surroundings. The third valve is disposed between the primary canister and an engine. The heater is configured to heat the primary and secondary canisters. The controller is programmed to (i) activate the heater to heat the primary and secondary canisters and (ii) purge the evaporated fuel from the primary and secondary canisters after heating the primary and secondary canisters.