A method controls an opening speed of a purge valve according to the purge gas concentration implemented by an active purge system (APS). A purge controller varies, when a valve opening speed of a purge control solenoid valve (PCSV) is controlled, the valve opening speed of the PCSV using any one among a low concentration rate coefficient, a high concentration rate coefficient, a coolant temperature rate coefficient, and an ambient air temperature rate coefficient, and performs the purge control using a difference between the valve opening speeds, and thus dualizes the valve opening speed of the PCSV according to a hydrocarbon (HC) concentration, thereby stably controlling the air-fuel ratio, and simultaneously, securing the purge rate and relatively stably control an air-fuel ratio in a state of high concentration purge execution.

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.

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.

During execution of a purge, a purge concentration-related value is learned based on an air-fuel ratio deviation that is a deviation of an air-fuel ratio detected by an air-fuel ratio sensor from a required air-fuel ratio. In this case, the purge concentration-related value is updated using an update amount with a smaller absolute value when the purge is a second purge of supplying evaporated fuel gas to an intake pipe through a second purge passage than when the purge is a first purge of supplying the evaporated fuel gas to the intake pipe through a first purge passage.

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 engine device is equipped with an engine that is supplied with fuel from a fuel tank and that has a throttle valve arranged in an intake pipe, a supercharger that has a compressor arranged in the intake pipe, and an evaporative fuel treatment device that has a supply pipe for supplying evaporative fuel gas containing evaporative fuel generated in the fuel tank to the intake pipe in a region upstream of the compressor, and a purge valve provided in the supply pipe. Moreover, the throttle valve is controlled such that an opening degree of the throttle valve becomes larger when upstream purge for supplying evaporative fuel gas to the intake pipe via the supply pipe is carried out than when upstream purge is not carried out, while the supercharger is in operation.

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 first arrival flow rate that is a flow rate of evaporative fuel gas that has arrived in a throttle downstream portion located downstream of a throttle valve in an intake pipe via a second purge passage after passing through a purge control valve is estimated based on a valve passage flow rate that is a flow rate of evaporative fuel gas that has passed through the purge control valve, and a first response delay in the flow of evaporative fuel gas through a route extending from the purge control valve to the throttle downstream portion via the second purge passage.

A method for increasing a purge rate of fuel evaporation gas of a vehicle may include: determining, by a controller, a first fuel evaporation gas density in a purge pump included in an active fuel evaporation gas purge system of the vehicle; filtering the first fuel evaporation gas density using a filter for controlling an amount of change in the first fuel evaporation gas density; determining a second fuel evaporation gas density in the purge pump based on the filtered first fuel evaporation gas density; determining a third fuel evaporation gas density in a standard temperature and pressure state; determining a concentration of hydrocarbon within the fuel evaporation gas based on the third fuel evaporation gas density; and increasing the purge rate of the fuel evaporation gas based on the hydrocarbon concentration in the fuel evaporation gas.