A hybrid vehicle includes a canister that adsorbs evaporative fuel generated in the fuel tank for an internal combustion engine. The hybrid vehicle can drive a drive wheel even when the internal combustion engine is stopped. When the internal combustion engine of the hybrid vehicle is stopped and a prescribed set of conditions is satisfied, the internal combustion engine is rotated by the generator. When the internal combustion engine of the hybrid vehicle is rotated by the generator, the evaporative fuel adsorbed in the canister is supplied to the upstream side of an upstream side exhaust catalytic converter device. In the hybrid vehicle, the introduced evaporative fuel as reducing agent is adsorbed in the upstream side exhaust catalytic converter device and a downstream side exhaust catalytic converter device.

A concentration measuring device includes a circulation passage, an aspirator, a differential pressure sensor, and a control unit. The aspirator is disposed in a fuel tank and is connected to the circulation passage. While a gas flows from a gaseous layer within a fuel tank through the circulation passage due to a negative pressure generated in the aspirator, the differential pressure sensor measures a pressure difference of the gas within the circulation passage between an upstream side of a narrowed part, having a narrower passage area than an adjacent portion of the circulation passage, and a downstream side of the narrowed part. The control unit is configured to calculate a density of the fuel vapor from the pressure difference of the gas and to calculate a concentration of the fuel vapor from the density of the fuel vapor.

Methods and systems are provided for controlling a vehicle engine to reduce engine knock and increase fuel efficiency by reducing hydrocarbon breakthrough. In one example, a method may include adjusting a compression ratio of a variable compression engine in response to hydrocarbon breakthrough above a threshold from a fuel vapor canister of an evaporative emissions system.

Methods and systems are presented for diagnosing a breach of an evaporative emissions system. The methods and systems include repurposing a resonator as a vacuum reservoir to reduce a pressure of an evaporative emissions system so that it may be determined if there is or is not a breach of the evaporative emissions system.

Methods and systems are provided for carrying out diagnostics of a bleed canister of an evaporative emissions control system in a vehicle. In one example, a method may include, loading the bleed canister during a refueling event, and then during an immediately subsequent engine start, detecting if the bleed canister is degraded or not based on output of an exhaust gas oxygen sensor.

Methods and systems are provided for an evaporative emissions control system for onboard refueling vapor recovery of a heavy duty vehicle. In one example, a method may include adjusting flow among at least two canisters during canister purging, where the at least two canisters are arranged in a parallel loading and unloading flow direction, to increase flow through a higher loaded canister. Flow may be adjusted using a first valve coupled to the first canister, a second valve coupled to the second canister, and so on for n number of canisters and n number of valves, and a balancing valve used to selectively couple the at least two canisters to a fuel tank.

A concentration measuring device includes a circulation passage, an aspirator, a differential pressure sensor, and a control unit. The aspirator is disposed in a fuel tank and is connected to the circulation passage. While a gas flows from a gaseous layer within a fuel tank through the circulation passage due to a negative pressure generated in the aspirator, the differential pressure sensor measures a pressure difference of the gas within the circulation passage between an upstream side of a narrowed part, having a narrower passage area than an adjacent portion of the circulation passage, and a downstream side of the narrowed part. The control unit is configured to calculate a density of the fuel vapor from the pressure difference of the gas and to calculate a concentration of the fuel vapor from the density of the fuel vapor.

A method for improving accuracy of correction of fuel quantity at the time when a recirculation valve (RCV) is opened, may include a step of correcting injection amount of fuel based on consideration factors when the RCV is operated to be opened. The consideration factors include property values of a flow path of the RCV, the flow path being mounted to an intake pipe to connect between a front end of a compressor close to the atmosphere and a rear end of the compressor adjacent to combustion chambers, a first calculation value obtained by calculating amount of air to be introduced into the combustion chambers after circulating from the flow path of the RCV to the intake pipe, and a second calculation value obtained by calculating amount of hydrocarbon to be introduced into the flow path of the RCV by purging evaporative gas.

An embodiment is a method including controlling a purge fuel amount of an active purge system (APS), the controlling including correcting the purge fuel amount using a primary weighting factor obtained using an ambient air temperature and a hydrocarbon (HC) concentration in purge gas fuel as input values, and correcting the corrected purge fuel amount using a secondary weighting factor due to a purge learning value. Some embodiments further include controlling of the purge fuel amount applies a purge execution condition, and the purge execution condition on the basis of a negative pressure of an intake manifold and a vehicle speed of the vehicle in which a purge flow rate exhibits as being greater than or equal to a predetermined value.

A device for controlling purge of a vehicle includes: a state detector detecting state information to control purge of an engine; a controller generating an amount of fuel of each of cylinders of the engine using an amount of air of each cylinder, compensation information, a lambda control value, and an amount of a purge gas of the engine, checking a purge distribution coefficient according to an amount of an intake air for each cylinder when the state information satisfies a control entry condition, generating an amount of redistribution of the purge gas using the amount of the purge gas and the purge distribution coefficient, and generating an injection time for each cylinder using the amount of fuel, a conversion coefficient, and the amount of redistribution of the purge gas; and an injector injecting fuel in each cylinder during the injection time based on control of the controller.