Methods and systems for diagnosing operational status of a carbon filled canister heater are described. The methods and systems may include activating an evaporative emissions system heater, a pump, and a canister purge valve to determine if long chain hydrocarbons are released from a carbon filled canister. Release of long chain hydrocarbons from the carbon filled canister may be indicative of desired operation of a carbon filled canister heater.

Methods and systems are provided for reverse purging of a fuel vapor canister of an engine. In one example, a method may include heating a fuel vapor canister, sealing a fuel tank in order to generate a vacuum in the fuel tank, and in response to the pressure in the fuel tank reaching a target vacuum, initiating reverse purging of the fuel vapor canister.

Methods and systems are provided for controlling a vehicle engine to reduce engine knock and increase fuel efficiency by reducing hydrocarbon breakthrough. In one example, a method may include adjusting a compression ratio of a variable compression engine in response to hydrocarbon breakthrough above a threshold from a fuel vapor canister of an evaporative emissions system.

A fuel vapor treatment apparatus includes a controller configured to detect an abnormality in at least one of a first check valve, a second check valve, a second purge passage, a charging passage, and an ejector based on pressure detected by a pressure detector.

Methods and systems are provided for vehicle fuel tanks including multiple reservoirs. In one example, a method may include opening a canister purge valve of a fuel system responsive to a fuel level of a fuel tank transitioning above a first threshold fuel level, and closing the canister purge valve after flowing a pre-determined amount of fuel to the fuel tank while the canister purge valve is open.

A fuel system comprising a fuel tank, a mixing volume configured to mix fuel vapor and air, the mixing volume comprising an outlet configured to be fluidly coupled to an engine, and a fuel vapor line configured to fluidly couple the fuel tank to the mixing volume.

Methods and systems for deicing an engine air intake filter and an engine throttle are described. The methods and systems may include activating an evaporative emissions system heater and a pump to de-ice the engine air intake filter and the engine throttle. The deicing may be performed when an engine of a vehicle is not operating.

A fuel vapor treatment apparatus includes a controller configured to detect an abnormality in at least one of a first check valve, a second check valve, a second purge passage, a charging passage, and an ejector based on pressure detected by a pressure detector.

Methods and systems are provided for carrying out diagnostics of a bleed canister of an evaporative emissions control system in a vehicle. In one example, a method may include, loading the bleed canister during a refueling event, and then during an immediately subsequent engine start, detecting if the bleed canister is degraded or not based on output of an exhaust gas oxygen sensor.

A vehicle includes an engine, a fuel tank, a canister, a valve, and a damper. The canister is configured to receive and store evaporated fuel from the fuel tank. The valve is disposed between the canister and the engine. The valve is configured to open to deliver evaporated fuel from the canister to the engine. The valve is configured to close to inhibit delivering evaporated fuel from the canister to the engine. The damper is secured to valve. The damper is configured to dampen movement of the valve between open and closed positions.