An evaporated fuel treatment apparatus includes an abnormality determination unit that determines an abnormality of a purge passage. The abnormality determination unit changes an operating cycle of a purge control valve to a cycle longer than an initial set value while maintaining a duty ratio of the purge control valve set according to an operating state of an internal combustion engine, and determines an abnormality of the purge passage based on a first variation range and a second variation range calculated from a detection value detected by an airflow meter before and after the change of the operating cycle.

A control system for a vehicle includes a controller. The controller is configured to receive signals from a plurality of vehicle sensors, a vehicle communications system, a ride-share application, a navigation system, or a combination of these. The controller is configured to determine whether at least one of a plurality of conditions is met to execute a small leak test on a fuel system of the vehicle based on the signals, where the plurality of conditions include an available time segment to execute the small leak test, a level surface, a smooth surface, and a constant vehicular momentum. The controller is configured to execute the small leak test when at least one of the plurality of conditions is met.

An active dual purge system includes: an intake pipe, a compressor to compress air, a canister to collect an evaporation gas, a purge line extending from the canister to a front end of the compressor, a branch line branching off from the purge line and extending to a rear end of a throttle valve body, a purge pump installed in the purge line, a purge valve installed in the purge line, a vent valve installed in a vent line extending from the canister toward the atmosphere, a first sensor installed in the purge line, and a second sensor installed in the purge line, and a controller to perform different tests on the purge pump, the purge valve and the vent valve in different operating states, and diagnose whether at least one of the purge line, the branch line, or the vent line are abnormal using on-board diagnosis (OBD).

An evaporated fuel processing device includes a canister to which evaporated fuel generated in a fuel tank adheres; a purge passage passed through purge gas and connecting the canister and an intake pipe of an engine; a purge control valve provided on the purge passage and controlling a supply amount of the purge gas to the intake pipe by changing a duty cycle; a pump provided on the purge passage and feeding the purge gas from the canister to the intake pipe; and a controller control the duty cycle of the purge control valve. The controller detects a pressure difference between pressures at upstream and downstream ends of the purge passage while the purge gas is supplied, and corrects the duty cycle based on a supply amount of the purge gas with respect to the duty cycle with no influence of the pump, by using the detected pressure difference.

The method for calculating the fuel injection amount of a fuel vapor dual purge system may include the steps of calculating, by a controller, volumetric efficiency of a combustion chamber, determining, by the controller, a fuel vapor detection delay time at which the fuel vapor is detected in a surge tank according to the calculated volumetric efficiency of a combustion chamber, calculating, by the controller, a time at which the fuel vapor is injected into the combustion chamber based on the determined fuel vapor detection delay time, and calculating, by the controller, a fuel vapor total injection amount at the time at which the fuel vapor is injected into the combustion chamber. The method may be performed in a turbocharger operation section.

A method of diagnosing an engine purge system includes: obtaining, by a controller, a first measurement value by measuring a pressure of a secondary purge line when a boosting pressure from a compressor is greater than or equal to a predetermined reference pressure; obtaining, by the controller, a second measurement value by measuring a pressure of the secondary purge line while opening and closing a purge control solenoid valve when a throttle valve is deployed; determining, by the controller, whether at least one of the secondary purge line or a recirculation line is blocked by comparing the first measurement value and the second measurement value; and providing, by the controller, an alert when it is determined that at least one of the secondary purge line or the recirculation line is blocked.

A system for testing an evaporative emissions (EVAP) canister of a vehicle according to the present disclosure includes an evaporator configured to contain liquid fuel, a fuel vapor supply line configured to deliver a mixture of fuel vapor and carrier gas from the evaporator to the EVAP canister, and a fuel vapor supply valve disposed in the fuel vapor supply line. The test system further includes a gas density meter configured to measure a density of the fuel vapor mixture flowing through the fuel vapor supply line, and a valve control module configured to control a position of the fuel vapor supply valve to adjust a flow of fuel vapor from the evaporator to the EVAP canister based on the fuel vapor mixture density.

A device may determine whether there is a communicated point with open air between a pump and a control valve or on an opposite side to the control valve of the pump, by at least two of pressures: between the pump and the control valve in case the control valve is in a cutoff state, the switching valve is in a communication state, and the pump sends in forward direction, on an opposite side to the control valve of to the pump in case the control valve is in a communication state, the switching valve is in the cutoff state, and the pump sends in reverse direction; and between the pump and the control valve or on the opposite side to the control valve of the pump in case the valves are in the cutoff states and the pump is stopped after one of these cases.

Methods and systems are provided for conducting an evaporative emissions test diagnostic on a vehicle fuel system and evaporative emissions control system during engine-on conditions. In one example, a first fuel vapor storage device is separated from a second fuel vapor storage device by a one-way check valve, thus preventing loading of the first fuel vapor storage device during conditions such as refueling operations, diurnal temperature fluctuations, or from running-loss vapors from a vehicle fuel tank. In this way, the evaporative emissions test diagnostic may be conducted during a cold-start event where an exhaust catalyst is below a predetermined threshold temperature required for catalytic oxidation of hydrocarbons in the engine exhaust, without increasing undesired exhaust emissions.

A method of diagnosing an engine purge system includes: obtaining, by a controller, a first measurement value by measuring a pressure of a secondary purge line when a boosting pressure from a compressor is greater than or equal to a predetermined reference pressure; obtaining, by the controller, a second measurement value by measuring a pressure of the secondary purge line while opening and closing a purge control solenoid valve when a throttle valve is deployed; determining, by the controller, whether at least one of the secondary purge line or a recirculation line is blocked by comparing the first measurement value and the second measurement value; and providing, by the controller, an alert when it is determined that at least one of the secondary purge line or the recirculation line is blocked.