A dual path fuel vapor purge system is disclosed for an engine having a turbocharger or a super. The purge system includes a canister configured to collect fuel vapor from a fuel tank. A canister purge valve is provided downstream from the canister. An ejector valve receives fuel vapors from the canister through the canister purge valve. A first vapor purge path directs the fuel vapor to an intake manifold of the engine. A second vapor purge path directs fuel vapor to an air induction system. A check valve downstream from the ejector valve receives the fuel vapor from the ejector and supplies the fuel vapor to the air induction system. Boost flow opens the check valve when the air induction system is in operation to boost the engine and closes the check valve when the engine is in operation with normal aspiration or when a leak is detected.

A method is provided for operating an internal combustion engine, which comprises at least one combustion unit, a fresh gas tract for supplying fresh gas to the combustion unit, and a fuel tank system. A fresh gas compressor as well as a differential pressure valve are integrated into the fresh gas tract. The first purge gas line opens into a first section of the fresh gas tract, which is situated downstream from the differential pressure valve as well as upstream from the fresh gas compressor, while the second purge gas line opens into a second section of the fresh gas tract situated downstream from the fresh gas compressor. The differential pressure valve is at least partially closed at least temporarily during an intake mode of the internal combustion engine with fuel vapor filter purging, and purge gas is introduced into the fresh gas tract via the first purge gas line.

The present disclosure relates to a method for removing residual purge gas in operating an active purge system and includes determining evaporation gas purge stop in a control unit, closing a PCSV mounted on a purge line connecting a canister and an intake pipe, and determining whether all of the evaporation gas flowed into the intake pipe is flowed into a combustion chamber, so that all of the evaporation gas flowed into an intake pipe during travelling can be flowed into and combusted in the combustion chamber.

When an execution condition for a purge of supplying evaporated fuel gas to an intake pipe is met, a required purge ratio is set within a range equal to or higher than a lower-limit purge ratio, and a purge control valve is controlled using a driving duty based on the required purge ratio. In this case, when the execution condition is continuously met, an ejector pressure is estimated based on a pressure difference between a supercharging pressure and a pre-compressor pressure, and on the driving duty, and the lower-limit purge ratio is set based on a post-throttle-valve pressure and on the ejector pressure. The value of the lower-limit purge ratio is set to zero immediately after the execution condition switches from being not met to being met.

Fuel injection control of an engine is executed by setting a required injection amount and an air-fuel ratio correction amount. When setting conditions are met, the air-fuel ratio correction amount is set for a corresponding region to which a current intake air amount or load ratio belongs among a plurality of regions into which the range of the intake air amount or the load ratio is divided such that a region of a larger intake air amount or a higher load ratio becomes wider than a region of a smaller intake air amount or a lower load ratio. When purge conditions are met, a purge control valve is controlled such that purge of supplying an evaporated fuel gas to an intake pipe is executed based on a required purge ratio.

An evaporated fuel processing device for a forced induction internal combustion engine according to the present invention includes: a first purge path extending from the downstream of a purge control valve to an intake pipe at the downstream of a throttle valve; and a second purge path extending from the downstream of the purge control valve to an ejector provided in a reflux pipe providing communication between the intake pipe at the downstream of a compressor and the intake pipe at the upstream of the compressor. The evaporated fuel processing device switches first control characteristic data for the first purge path and second control characteristic data for the second purge path, when the first purge path and the second purge path are switched.

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.

A method of detecting a leak in an evaporative emissions system includes sealing an evaporative emissions system, achieving a first target pressure in the evaporative emissions system, achieving a second target pressure in the evaporative emissions system after achieving the first target pressure, and monitoring a system pressure subsequent to the second target pressure achieving step to determine a leak condition of the evaporative emissions system.

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 method is provided for operating an internal combustion engine, which comprises at least one combustion unit, a fresh gas tract for supplying fresh gas to the combustion unit, and a fuel tank system. A fresh gas compressor as well as a differential pressure valve are integrated into the fresh gas tract. The first purge gas line opens into a first section of the fresh gas tract, which is situated downstream from the differential pressure valve as well as upstream from the fresh gas compressor, while the second purge gas line opens into a second section of the fresh gas tract situated downstream from the fresh gas compressor. The differential pressure valve is at least partially closed at least temporarily during an intake mode of the internal combustion engine with fuel vapor filter purging, and purge gas is introduced into the fresh gas tract via the first purge gas line.