A device for discharging fuel vapor from a fuel supply system for an internal combustion engine has a container which is situated in the fuel supply system and contains liquid fuel under an upwardly limited pressure. A discharge line, which leads to a tank venting system, leads out of the container. The device also has a detector for detecting vaporous fuel in the container and a blocking device which is coupled to the detector and with which the discharge line can be opened or blocked depending on the detection. A method for discharging fuel vapor from a fuel supply system for an internal combustion engine continuously detects whether vaporous fuel is also present in the container which is situated in the fuel supply system and contains the liquid fuel under an upwardly limited pressure; opens the discharge line if the vaporous fuel has been detected and blocks the discharge line if no vaporous fuel has been detected; and discharges the vaporous fuel through the opened discharge line while retaining the liquid fuel.

Techniques for controlling a forced-induction engine having a low pressure cooled exhaust gas recirculation (LPCEGR) system comprise determining a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation and boost device inlet pressure hardware limits for a set of components in the induction system, determining a final target boost device inlet pressure based on the determined sets of target boost device inlet pressures and boost device inlet pressure hardware limits, and controlling a differential pressure (dP) valve based on the final target boost device inlet pressure to balance (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.

An evaporative emission control system for a vehicle includes an engine, a fuel tank connected to the engine and a reversible purge pump connected between the fuel tank and the engine. Fuel vapor generated in the fuel tank is supplied to the engine. The purge pump is operable in a first direction to supply the fuel vapor from the fuel tank to the engine and a second direction to supply air to the fuel tank. A purge control valve is connected between the reversible purge pump and the engine to control a flow of the fuel vapor to the engine.

A control device transmits an opening degree command amount to an actuator to command an opening degree of a sealing valve. The control device learns a valve opening start amount in a learning operation based on the opening degree command amount when pressure of vapor-phase gas in a fuel tank starts to decrease in response to the opening degree command amount that gradually increases from zero. The control device sets a valve opening threshold, which is for determining that pressure of vapor-phase gas has started to decrease, based on a before-learning pressure, which is pressure of vapor-phase gas before the learning operation is started. The control device determines the opening degree command amount based on the valve opening start amount unit when causing the sealing valve to open to perform a vapor operation or a purge operation.

In at least some implementations, a charge forming device for a combustion engine includes a housing, a throttle valve and a vent valve. The housing has an inlet chamber in which a supply of fuel is received, a vent passage communicating with the inlet chamber and a throttle bore with an inlet through which air is received. The throttle valve is carried by the housing and has a valve head movable relative to the throttle bore to control fluid flow through the throttle bore. And the vent valve is electrically actuated, carried by the housing and has a valve element that is movable between an open position wherein fluid may flow from the inlet chamber through the vent passage and a closed position where fluid is prevented or inhibited from flowing out of the inlet chamber through the vent passage.

Methods and systems are provided for conducting vehicle fuel system and/or evaporative emissions system diagnostics, where the diagnostics rely on a positive pressure with respect to atmospheric pressure. In one example, a method comprises activating an electric compressor positioned in an intake of an engine configured to receive purge gasses from the evaporative emissions system under boosted engine operation and natural engine operation, to direct a positive pressure with respect to atmospheric pressure to the fuel system and/or evaporative emission system to conduct said diagnostic. In this way, diagnostics that rely on positive pressure with respect to atmospheric pressure may be conducted in vehicles with a dual-path purge system, without introduction of a pump in the evaporative emissions system.

An vapor purge system for a turbocharged internal combustion engine having an evaporative emissions turbo purge valve incorporating a venturi vacuum generator and a hose-off detection function. The turbo purge valve includes a pressure sensor, and a low restriction check valve which is integrated into the outlet port of the venturi vacuum generator. The pressure sensor is capable of detecting the small pressure drop (i.e., vacuum) generated at the air inlet tube or air box during naturally aspirated conditions. The check valve closes the venturi vacuum generator on the purge side during naturally aspirated conditions, allowing fluid communication to the air intake system through one port only, and the detection of the vacuum during these conditions. If a hose becomes detached, either at the outlet port of the venturi vacuum generator or at the air box, the small vacuum is not detected, and the ECU then diagnoses the hose-off condition.

Methods and systems are provided for determining an offset of a pressure sensor that is used for monitoring pressure in a fuel system that is sealed expect for refueling and other diagnostic events. In one example, a method includes waking a controller of a vehicle when it is expected that a pressure in a fuel system that is sealed from atmospheric pressure is at atmospheric pressure, unsealing the fuel system, and indicating an offset of the pressure sensor based on a pressure change after the fuel system is unsealed. In this way, pressure sensor offset may be determined regularly without undesirably loading a fuel vapor storage canister with vapors, which may be particularly advantageous for hybrid vehicles.

An active purge system may include: a canister to collect therein an evaporation gas evaporated from a fuel tank; a purge line to connect the canister to an intake pipe; a purge pump to pressurize the evaporation gas to allow the evaporation gas to move from the canister to the intake pipe; a purge valve installed on the purge line to be located between the purge pump and the intake pipe; and an engine connected to the intake pipe. In particular, the engine includes an injector installed on a cylinder head, an intake valve, and an exhaust valve.

An evaporative emissions control system comprising an evaporative emissions control (evap) canister. A fuel vapor feed conduit includes a first end fluidically connected to the evap canister, a second end connected to an internal combustion (IC) engine and a purge valve fluidically connected thereto. A fuel vapor conduit includes a first end fluidically connected to the evap canister and a second end configured to extend into a vehicle fuel tank. A fuel vapor vent valve is fluidically connected to the fuel vapor conduit at the second end thereof. A vapor return system includes a fuel pump fluidically connected to the fuel vapor conduit through an intermediate bypass conduit having a first end fluidically connected to an intermediate portion of the fuel vapor conduit and a second end extending into the vehicle fuel tank and in communication with the vapor return system.