Methods and systems are provided for reducing engine stall incidence during canister purging. A fuel vapor canister is purged at a higher purge ramp rate to an engine with one or more cylinders selectively deactivated. In response to an indication of potential or partial engine stall, the deactivated cylinders are reactivated and the canister purge ramp rate is lowered.

Methods and systems are provided for cleaning a fuel vapor storage canister positioned in an evaporative emissions control system of a vehicle. In one example, a method comprises sealing a fuel system of the vehicle for descending an altitude change that is predicted in advance, and subsequent to the vehicle descending the altitude change, unsealing the fuel system to passively purge fuel vapors stored in the fuel vapor storage canister to a fuel tank of the vehicle. In this way, bleed through emissions from the fuel vapor storage canister may be reduced, and engine operation may be improved.

Methods and systems are provided for depressurizing a fuel tank of a vehicle by routing fuel tank vapors to an engine for combustion. In one example, a method may include reducing a pressure in the fuel tank by routing vapors from the fuel tank through a portion of a fuel vapor storage canister and, in response to an indication of a condition of degraded engine stability, re-routing the vapors from the fuel tank through an entirety of the fuel vapor storage canister. In this way, under conditions of degraded engine stability, a rate at which fuel tank vapors are directed to the engine may be reduced, which may thus mitigate the condition of degraded engine stability without aborting the operation to reduce the fuel tank pressure.

Methods and systems are provided for depressurizing a fuel tank of a vehicle by routing fuel tank vapors to an engine for combustion. In one example, a method may include reducing a pressure in the fuel tank by routing vapors from the fuel tank through a portion of a fuel vapor storage canister and, in response to an indication of a condition of degraded engine stability, re-routing the vapors from the fuel tank through an entirety of the fuel vapor storage canister. In this way, under conditions of degraded engine stability, a rate at which fuel tank vapors are directed to the engine may be reduced, which may thus mitigate the condition of degraded engine stability without aborting the operation to reduce the fuel tank pressure.

An automobile power system in a vehicle may include an intake pipe supplying external air to an engine supplying power to driving wheels, a canister connected with a fuel tank to absorb evaporation gas produced in the fuel tank, an active purging system compressing and supplying the evaporation gas absorbed in the canister to the intake pipe, a diverging line extending from the active purging system to the engine, a diverging valve mounted on the diverging line, and a starting motor rotating a crankshaft when the engine is started. In addition, the evaporation gas absorbed in the canister is supplied to the engine through the diverging line before the engine is restarted, and then the starting motor is operated.

An intake and exhaust system for preventing generation of condensed water may include: an exhaust gas recirculation (EGR) system circulating some of combustion gas from an exhaust pipe to an intake pipe; an active purging system compressing and supplying evaporation gas generated from a fuel tank to the intake pipe; and a controller to control the EGR system and the active purging system. In particular, the controller calculates a saturated water vapor pressure based on temperature at a position between the EGR system and the intake pipe, and calculates a saturated water vapor pressure based on temperature of the intake pipe and then compares one of the two saturated water vapor pressures with a water vapor pressure of intake air so as to reduce an EGR rate of the EGR system or a purging rate of the active purging system based on the comparison result.

A mixture-lubricated four stroke engine has a cylinder in which a combustion chamber is formed. The combustion chamber is delimited by a piston which is mounted movably in the cylinder. The engine has an intake channel which discharges into the combustion chamber via an inlet opening controlled by an inlet valve. A mixture formation unit includes at least one fuel opening which discharges into the intake channel. For the lubrication of the crankcase interior, a flow connection connects the intake channel to the crankcase interior via a connecting opening which discharges into the intake channel downstream of the mixture formation unit. The fuel quantity is controlled by a fuel valve. A control unit is configured to activate the fuel valve in a manner dependent on the position of the crankshaft such that the fuel valve is opened at least also during a part of the compression stroke.

Methods and systems are provided for indicating whether a canister purge valve in a vehicle evaporative emissions control system is degraded. In one example, an air intake system hydrocarbon (AIS HC) trap temperature may be monitored during a refueling event, and responsive to an indication that the AIS HC trap temperature change is greater than a predetermined threshold, it may be indicated that the canister purge valve is degraded. In this way, diagnosis of whether a vehicle canister purge valve is degraded may be indicated without the use of engine manifold vacuum, and may be advantageous for vehicles configured to operate for significant amounts of time without engine operation, or without intake manifold vacuum.

Methods and systems are provided for cleaning one or more valve(s) that regulate an amount of fuel vapor routed to an engine of a vehicle in response to an indication that the one or more valve(s) are exhibiting degraded sealing properties. In one example, a method includes timing opening and closing events of the valve to coincide with higher than a threshold pressure differences across the valve as compared to lower than the threshold pressure differences in terms of pressure oscillations across the valve, the pressure oscillations stemming from an intake of the engine. In this way, the one or more valve(s) may be controlled to open under higher loads and stresses on the valve(s), which may dislodge debris, carbon buildup, etc., thus serving to clean the valve.

Systems and methods for operating an engine in response to a condition of an engine air intake throttle being degraded are presented. In one example, the engine air intake throttle is held closed while a position of a fuel vapor storage canister vent valve is adjusted to control air flow into the engine based on a position of an accelerator pedal. In this way, the engine air amount may be adjusted to provide additional torque from an engine while a throttle is degraded.