Methods and systems are provided for routing secondary air to engine an exhaust system during a cold-start condition to reduce tail pipe emissions. In one example, a method may include operating a pump of an evaporative leak check module (ELCM) in a positive pressure mode and routing pressurized air to the exhaust passage upstream of an exhaust catalyst via an air conduit housing a first valve.

A vapor fuel processing includes a canister for absorbing vapor fuel, a purge pipe, a purge control valve, a pump, a pressure sensor, and a determination unit. The pump may be provided on the purge pipe upstream of the purge control valve. The pressure sensor may be provided between the purge control valve and the pump. The determination unit may determine a state of a purge path by comparing a first detected value of the pressure sensor detected when the pump is driven with the purge control valve in a cutoff state with a first reference value and then comparing a second detected value of the pressure sensor detected when the pump is driven with the purge control valve in the communicated state with a second reference value.

An evaporated fuel treatment apparatus includes a canister, a purge passage, a purge pump, a purge valve, and a controller for executing purge control. The controller is configured to switch the purge valve to a closed state or an open state once, subsequently set a concentration sensing flag to ON, and then detect a purge concentration based on a pump downstream pressure or a pump differential pressure at a predetermined timing elapsed by a predetermined time from setting of the concentration sensing flag to ON.

A fuel injection valve is controlled by setting a required injection amount using a required load factor of an engine and a purge correction amount. A purge control valve is controlled using a driving duty based on a required purge ratio when a purge of supplying the evaporated fuel gas to an intake pipe is being executed. During execution of the purge, the purge concentration-related value is learned based on an air-fuel ratio deviation that is a deviation of an air-fuel ratio from a required air-fuel ratio. The certainty of the purge concentration-related value is estimated using a first counter that reflects a number of times of learning of the purge concentration-related value during a first purge and that does not reflect a number of times of learning of the purge concentration-related value during a second purge.

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.

A fuel injection valve is controlled by setting a required injection amount using a required load factor of an engine and a purge correction amount. A purge control valve is controlled using a driving duty based on a required purge ratio when a purge of supplying the evaporated fuel gas to an intake pipe is being executed. During execution of the purge, the purge concentration-related value is learned based on an air-fuel ratio deviation that is a deviation of an air-fuel ratio from a required air-fuel ratio. The certainty of the purge concentration-related value is estimated using a first counter that reflects a number of times of learning of the purge concentration-related value during a first purge and that does not reflect a number of times of learning of the purge concentration-related value during a second purge.

When first switching of switching from a first purge of supplying evaporated fuel gas to an intake pipe through a first purge passage to a second purge of supplying the evaporated fuel gas to the intake pipe through a second purge passage occurs and then second switching of switching from the second purge to the first purge occurs, a purge concentration-related value is corrected to a value closer to a first stored value that is the purge concentration-related value immediately before the first switching than to a second stored value that is the purge concentration-related value immediately before the second switching.

An autonomous vehicle and a method of controlling the vehicle are provided. The vehicle has an accessory powered by an engine with a compressor. An ejector has an inlet positioned to receive compressed air from the air intake system downstream of the compressor, and an outlet positioned to provide compressed air into the air intake system upstream of the compressor. A check valve is positioned between and fluidly connects the canister purge valve and the ejector. A controller is configured to stimulate boosted operation of the engine by activating the accessory and increasing a torque output of the engine to open the second check valve.

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.

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.