Patent Application
20230358192
This disclosure relates to methods and systems for controlling dust ingestion into a vehicle fuel vapor storage canister.
Vehicle fuel systems include evaporative emission control systems designed to reduce the release of fuel vapors to the atmosphere. For example, vaporized hydrocarbons (HCs) from a fuel tank may be stored in a fuel vapor canister packed with an adsorbent which adsorbs and stores the vapors. When the engine is in operation, the evaporative emission control system allows the vapors to be purged into the engine intake manifold for use as fuel.
The engine when running generates manifold vacuum. When a canister purge valve is opened air is drawn into the fuel vapor canister by the vacuum to remove fuel vapor that was previously adsorbed by an adsorbent contained in the canister.
Vehicles may be operated in dusty environments such as unpaved roads and when off-road driving. Fuel vapor canisters are supplied with air through a dust box having filters that remove dust from the air when air is drawn into the canister when purging. If the dust box filters are clogged by a large amount of dust, the flow of air to the canister may become restricted and the canister may be unable to purge efficiently. A clogged dust box may cause premature shut offs during refilling.
Fine dust particles may pass through the filters in the dust box and may cover carbon pellets inside the canister that may affect evaporative emission adsorption and desorption working capacity.
This disclosure is directed to solving the above problems and other problems as summarized below.
According to one aspect of this disclosure, a system is disclosed for providing purge air from an engine intake system to a vapor storage canister when the quantity of dust particles in the vicinity of a vehicle is above a predetermined threshold. The system includes a fuel tank having at least one grade limit venting valve, and a fuel limit venting valve. A fuel filler conduit that the grade limit venting valve and the fuel limit venting valve that open into and a filler neck for supplying fuel to the fuel tank. A fuel tank pressure sensor monitors a pressure in the fuel filler conduit. A vapor storage canister of an evaporative emission system includes a buffer and the fuel filler conduit transfers fuel vapor through the buffer to the vapor storage conduit. The vapor storage conduit encloses a fuel vapor storage medium that stores the fuel vapor until the canister is purged. An air vent supplies purge air to the vapor storage canister through a first air supply conduit and purge air is selectively drawn into the air vent through a dust box under normal driving conditions. An intake manifold is adapted to supply air to the vehicle engine. Purge air is selectively drawn into the vapor storage canister through a second air supply conduit through the intake manifold air filter. A valve is provided in the first air supply conduit and the second air supply conduit. A source of data is referenced that indicates the quantity of dust particles in the environment where a vehicle is operated. A controller passes the stored fuel vapor into the intake manifold when the engine is operating and when the canister is purged. The controller is responsive to the data indicating the quantity of dust to control providing purge air from the first air supply conduit through the dust box to the vapor storage canister when the quantity of dust particles is below a predetermined threshold, and provides purge air from the second air supply conduit from the engine intake system to the vapor storage canister when the quantity of dust particles is above the predetermined threshold.
According to other aspects of this disclosure relating to the above aspect of the disclosure, the valve may be a three-way valve with a first port that is opened to provide purge air from the first air supply conduit, a second port that is opened to provide purge air from the second air supply conduit, and a third port that prevents purge air from being provided to the vapor storage canister in a leak test mode.
The source of data may be an on-board sensor, or the source of data may be data from a source external to the vehicle that provides data via a modem on the vehicle relating to the extent of dust in the environment of the vehicle.
According to another aspect of this disclosure, a system is disclosed that includes a fuel tank having a filler neck for supplying fuel to the fuel tank. A vapor storage canister of an evaporative emission system stores fuel vapor received from the filler neck and fuel tank. A source of data received from onboard or external sources that indicate a quantity of dust particles in the environment of the vehicle and a controller responsive to the data indicating the quantity of dust. A valve responsive to the controller provides purge air from a first source of purge air through a dust box to the vapor storage canister when the quantity of dust particles is below a predetermined threshold. The valve provides purge air from a second source of purge air from an engine intake system to the vapor storage canister when the quantity of dust particles is above the predetermined threshold.
According to alternative aspects of the above the system, the source of data may be an on-board sensor, such as a camera, or may be a laser, an infrared sensor, or an optical sensor.
Alternatively, the source of data is data may be obtained from a global positioning map indicating that the vehicle is not being operated on a paved road or may be obtained from a source external to the vehicle that provides data via a modem on the vehicle relating to the extent of dust in the environment of the vehicle.
The controller may select the source of purge air by switching a valve to provide purge air from the first source or the second source. The valve may be a three-way valve with a first port that is opened to provide purge air from the first source, a second port that is opened to provide purge air from the second source, and a third port that prevents purge air from being provided to the vapor storage canister in a leak test mode.
This disclosure also comprehends a method for controlling a source of purge air supplied to a vapor storage canister of an evaporative emission system. Based upon a sensed volume, or density, of dust particles in an environment of a vehicle, purge air for the vapor storage cannister may be switched from a first source of purge air through a dust box or from a second source of purge air obtained from an engine intake system.
The above aspects of this disclosure and other aspects will be described below with reference to the attached drawings.
The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts.
Various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more of the other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure could be used in particular applications or implementations.
Referring to
A front dust sensor 24 and/or a rear dust sensor 26 may be provided onboard the vehicle 10. The front dust sensor 24 may be preferred as it will be able to detect dusty conditions around a moving vehicle at an earlier time as it enters the dusty area. The rear dust sensor may be preferred if it is already provided on the vehicle, for example it may be a pre-existing back up camera.
In dusty conditions when the volume or density of dust in the environment of the vehicle 10 is greater than a predetermined level, such as when driving off-road, or on an unpaved road, it may be preferred to bypass the dust box 22 and provide purge air through a second purge air line that takes air from the intake manifold 28 of the engine 30. The intake manifold 28 receives air through the engine air filter that is easily changed if it becomes filled with dust.
A controller 34 is provided that receives data indicating the level of dust in the environment of the vehicle 10 from onboard sources such as the front dust sensor 24, rear dust sensor 26, a dust sensor in a different location. Alternatively, a modem that may be part of the controller 34 may be used to receive data from an external source, such as a global positioning system (GPS) map indicating an unpaved road or off-road location, or from reports of weather conditions that may be received from a broadcast, the internet, or local environmental sensors.
Referring to
A fuel tank pressure transducer 48 monitors the pressure in the fuel tank and in the fuel vapor recovery conduit 38. The fuel vapor recovery conduit 38 releases fuel vapor to a buffer 50 of the fuel vapor storage cannister 18. Fuel vapor is stored in an adsorbent material in the fuel vapor storage cannister 18, for example, the adsorbent material may be activated carbon.
In a normal mode illustrated in
A cannister vent valve 60 in the normal mode draws air through the dust box 22 and a first air purge line 20 and to the fuel vapor storage container 18 as the stored fuel vapor is ported to the intake manifold 28. The cannister vent valve 60 is a three-way valve controlled by the controller 34.
Referring to
Referring to
In dusty conditions when the volume or density of dust, or sensed extent of dust, in the environment of the vehicle 10 is greater than the predetermined level, the controller receives data indicating the level of dust in the environment of the vehicle 10 from onboard sources or from an external source. Examples of onboard sources include a laser sensor, an infrared sensor, an optical sensor, a camera, or the like. The onboard sources may be located at the front, rear or any convenient location on the vehicle.
A modem may be included as part of the controller 34 or may be a separate module. The modem may receive data from an external source, for example, a GPS system map indicating an unpaved road or off-road location, from reported weather conditions, or local environmental sensors.
A controller 34 is provided that receives the data indicating the level of dust in the environment of the vehicle 10 from onboard sources such as the front dust sensor 24, rear dust sensor 26, a dust sensor in a different location. Alternatively, a modem that may be part of the controller 34 may be used to receive data from an external source, such as a GPS system map indicating an unpaved road or off-road location, or from reports of weather conditions that may be received from a broadcast, the Internet, or local environmental sensors.
The embodiments described above are specific examples that do not describe all possible forms of the disclosure. The features of the illustrated embodiments may be combined to form further embodiments of the disclosed concepts. The words used in the specification are words of description rather than limitation. The scope of the following claims is broader than the specifically disclosed embodiments and includes modifications of the illustrated embodiments. In addition, the features of various implementing embodiments may be combined to form further embodiments of the invention.
