Methods and systems are provided for reducing degradation and issues related to noise, vibration and harshness (NVH) for a fuel tank pressure control valve configured to seal a fuel tank from atmosphere. In one example, a method may include depressurizing the fuel tank of a vehicle by duty cycling a tank pressure control valve and routing fuel vapors from the fuel tank to an engine, while controlling a timing of opening and closing events of the tank pressure control valve to coincide with pressure differences across the tank pressure control valve less than a threshold pressure difference in terms of pressure oscillations across the tank pressure control valve. In this way, higher loads and stress on the tank pressure control valve may be avoided, thus reducing degradation and NVH issues.

A method for controlling an engine variable valve timing of a hybrid electric vehicle, may include providing a cam position setting table of a fuel efficiency prioritized intake/exhaust cam control mode, and a cam position setting table of a normal intake/exhaust cam control mode, the cam position setting table of the fuel efficiency prioritized intake/exhaust cam control mode being differentiated from the cam position setting table of the normal intake/exhaust cam control mode; selecting one of the fuel efficiency prioritized intake/exhaust cam control mode and the normal intake/exhaust cam control mode by a canister loading amount and whether or not diagnosis of an intake cam and diagnosis of an exhaust cam are completed; and determining position control values of the intake and exhaust cams by using the cam position setting table and then controlling positions of the intake cam and the exhaust cam by the determined position control values.

Methods and systems are provided for generating vacuum via a throttle. In one example, a method may comprise rotating the throttle to a first fully closed position to provide vacuum to a first vacuum consumption device and rotating the throttle to a second fully closed position to provide vacuum to a second vacuum consumption device. The method may further include rotating the throttle to a partially closed position to provide vacuum to both the first and second vacuum consumption devices.

Methods and systems are provided for controlling air flow through at least two aspirators coupled across an intake throttle. In one example, a method includes, during a first condition, opening a common aspirator shut-off valve to direct intake air through a first aspirator and a second aspirator each coupled across an intake throttle, and supplying vacuum generated by the first aspirator and the second aspirator to respective vacuum consumption devices as demanded. The method also includes, responsive to a second condition, closing the common aspirator shut-off valve and supplying intake manifold vacuum to the respective vacuum consumption devices as demanded.

An evaporative emissions control system for an internal combustion engine having an air intake manifold is provided. The system includes a carbon canister configured to receive fuel vapor, a purge valve fluidly coupled to the carbon canister, an air induction system configured to fluidly couple to the air intake manifold, a conduit fluidly coupled between the purge valve and the air induction system, and an inlet valve disposed in the air induction system. The inlet valve is configured to selectively move between an open position and a closed position to vary an air restriction in the air induction system and generate a vacuum. The vacuum draws fuel vapor from the carbon canister through the conduit into the air induction system.

A system for controlling a compressor may include an engine controller that controls a fuel injection amount corresponding to an engine load and an opening amount of a throttle by reflecting a required torque required for an air conditioner (A/C), an operation information detector for detecting operation information according to driving state of the vehicle, a compressor that generates pressure during operation of the A/C, an air conditioner relay which is turned on when the air conditioner operates and is turned off when the A/C is stopped, and a controller which determines an engine negative pressure of an intake manifold, and when the cooling water temperature is lower than the predetermined temperature and the intake manifold pressure is lower than the first threshold value, a cold-start intake manifold negative pressure insufficient event is generated to reduce the A/C duty in accordance with the entry into a negative pressure recovery mode.

An apparatus for purging fuel vapor includes: a turbocharger; a recirculation valve; a canister connected with a fuel tank through a vapor line and collecting fuel vapor of fuel stored in the fuel tank; a purge control solenoid valve installed in a main purge line connected with the canister and selectively blocking the fuel vapor collected in the canister; a first check valve; a second check valve; and a differential pressure creating valve installed in the intake line at the upstream portion of the compressor, and creating negative pressure.

A starting assistance method and device for an internal combustion engine supplied with a fuel that may contain ethanol, and including a fluid connection pipe between an intake manifold and a braking assistance device. The method including determining the engine temperature, determining the outdoor air temperature, blocking the pipe between the intake manifold and the braking assistance device for a given duration during a phase of starting the engine when the temperature of the engine is lower than a first threshold value and the outdoor air temperature is lower than a second threshold value, and freeing the pipe between the intake manifold and the braking assistance device when the engine is rotating autonomously.

An abnormality diagnostic device and an abnormality diagnostic method for a booster according to the present invention: determine that a negative pressure sensor operates normally, when an output of the negative pressure sensor changes in response to a decrease in intake pressure; determine that a negative pressure pump operates normally, when the pressure in a negative pressure chamber is decreased by operating the negative pressure pump, and the pressure decrease is determined by the negative pressure sensor determined to be normal; determine that the negative pressure pump is abnormal when the pressure decrease is not determined by the negative pressure sensor; and determine that a negative pressure leakage has occurred, when the pressure in the negative pressure chamber, which has been decreased by the negative pressure pump, is not maintained.

During a predetermined operation state in which the opening degree of a throttle valve is fixed, an air flow meter positioned more on the upstream side than a pressure control valve detects a first intake air amount when the opening degree of the pressure control valve positioned on the upstream side of the throttle valve is set to a predetermined first valve opening degree and a second intake air amount when the opening degree of the pressure control valve is set to a predetermined second valve opening degree smaller than the first valve opening degree. On the basis of the first intake air amount and the second intake air amount, a diagnosis is made regarding whether there is an abnormality in a first pipe, a second pipe, a third pipe and the like which are included in a blow-by gas recirculation system for blow-by gas treatment.