Embodiments for controlling fuel vapors are disclosed. In one example, a method comprises during a purge of a fuel vapor canister, adjusting a heater of the fuel vapor canister based on a rate of a purge flow exiting the fuel vapor canister and a concentration of hydrocarbons released from the fuel vapor canister. In this way, a fuel vapor canister purge efficiency may be increased.

A method for localizing restrictions in a fuel system during refueling, comprising: monitoring fuel tank pressure, fuel vapor canister temperature, and evaporative leak check module pressure during a refueling event; and responsive to a premature shutoff event, indicating a location of a restriction among a plurality of locations based on whether monitored pressure and temperature changes during the refueling event are greater than respective thresholds. In this way, the cause of a premature shutoff event may be diagnosed without requiring additional sensors within the fuel system.

Methods and systems are provided for improving the efficiency of canister purge completion. Based on engine operating conditions, a canister is purged to a compressor inlet or a throttle outlet. During purging conditions, as canister loads change, a purge flow through the canister is varied so that a fixed preselected portion of total engine fueling is delivered as fuel vapors.

A system according to the present disclosure includes a valve control module, a purge fraction module, and a diagnostic module. The valve control module opens a purge valve in an evaporative emissions system to allow purge vapor to flow to an intake system of an engine. The purge fraction module determines first and second fractions of purge vapor delivered to the engine relative to a total amount of air and purge vapor delivered to the engine based on first and second inputs, respectively. The first input is from a hydrocarbon sensor disposed in the evaporative emissions system of the engine. The second input is from an oxygen sensor disposed in an exhaust system of the engine. The diagnostic module selectively diagnoses a fault in at least one of the evaporative emissions system and the hydrocarbon sensor based on the first and second purge fractions when the purge valve is open.

Systems and methods for diagnosing individual components of an evaporative emissions system are presented. In one example, fuel vapor flow may be a basis for determining whether or not selected emission system components may be degraded. Further, fuel tank pressure may be another basis for determining component whether or not selected emissions system components may be degraded.

A fuel system is provided, comprising a solenoid valve positioned to regulate flow of fuel vapor between a fuel tank and a fuel vapor canister. The solenoid valve may include an indicator of changes in fuel vapor canister temperature resulting from fuel vapor adsorbing to adsorbent material within the fuel vapor canister and from fuel vapor desorbing from the adsorbent material. In this way, a working capacity of the fuel vapor canister may be determined during refueling and purge events.

Methods and systems are provided for controlling canister purge flow in a boosted engine. An example method for the boosted engine comprises, during boosted conditions, flowing stored fuel vapors from a canister into an ejector coupled in a compressor bypass passage, the flowing bypassing a canister purge valve. The method further comprises, responsive to a canister load higher than a threshold load, closing a canister vent valve coupled to the canister, and discontinuing flowing stored fuel vapors from the canister into the ejector.

An ejector, or arrangement having the ejector, has a compact structure requiring little installation space, permitting a sufficient pumping action, and, in case of an error, the error can be unambiguously detected and diagnosed as the source of the problem, which ejector for insertion into a receptacle, has a base element with a throat that fluid-connects a first opening and a second opening to each other, whereby the throat has a narrowest part that is fluid-connected to an associated third opening, and whereby the throat widens, at least in sections, towards the first and second openings, wherein, as a functional component, the ejector can be inserted into and/or positioned in a mating receptacle in the correct orientation so as to fulfill its function as a jet pump in an arrangement.

A controller for an internal combustion engine is provided. The engine includes a compressor, a three way catalyst, a canister, an evaporated fuel passage, an ejector, and a purge control valve. The controller includes an ECU. The ECU is configured to decrease an opening degree of the purge control valve in response to an increase in pressure on the downstream side of the compressor in a lean supercharging range. The is a range in which an operation air-fuel ratio of the internal combustion engine is leaner than a theoretical air-fuel ratio of the internal combustion engine, and in which the pressure on the downstream side of the compressor is higher than pressure on the upstream side of the compressor.

In a vaporized fuel processing apparatus in which fuel vapor within a fuel tank is adsorbed by a canister, the adsorbed vaporized fuel is drawn to an engine, a closing valve is provided connecting the fuel tank and the canister for controlling communication between the fuel tank and the canister, and a purge valve is provided connecting the canister and the engine for controlling communication between the canister and the engine. The vaporized fuel processing apparatus includes an internal pressure sensor configured to detect a pressure of a space within the fuel tank as an internal pressure, and a closing valve control means configured to open the closing valve for supplying an atmospheric pressure to the fuel tank via the canister when the sensor detects that the internal pressure of the fuel tank is negative, while the purge valve is closed. Therefore, the air/fuel ratio is prevented from being disturbed.