System and method for fuel tank diagnostics

Abstract

Methods and systems for performing fuel tank diagnostics are provided. In one example, the method includes: sealing a fuel tank of a vehicle; retrieving fuel tank pressure-related data from a fleet of vehicles; and, in response to the fuel tank pressure-related data from the fleet of vehicles not being sufficiently correlated with a fuel tank pressure-related data set from the vehicle, indicating degradation of the fuel tank of the diagnosed vehicle. In this way, fuel tank degradation can be indicated without connecting the fuel tank of the vehicle to the atmosphere, which can reduce the release of undesirable evaporative emissions to the atmosphere.

Description

Technical Field

[0001] The present description generally relates to methods and systems for determining whether a vehicle's fuel tank is degraded using vehicle-to-vehicle (V2V) communication technology.

[0002] Background Art / Summary of the Invention

[0003] A plug-in hybrid electric vehicle (PHEV) has a fuel tank that is sealed, for example, by a fuel tank isolation valve under the control of a vehicle controller. The fuel tank of a PHEV is sealed due to limited engine operating time. For example, a fuel vapor storage canister may be located in the evaporative emission system to capture and store fuel vapors from the fuel tank. When the engine is running, intake manifold vacuum is periodically applied to the fuel vapor canister to draw fuel vapors from the canister and deliver the vapors to the engine intake system for combustion. However, due to the limited engine operating time in a PHEV, if the fuel tank is not sealed (e.g., vented to the atmosphere), extended periods of pure electric operation of the vehicle may cause the fuel vapors to overload the canister, which may further cause undesirable evaporative emissions (e.g., hydrocarbons) to be emitted into the atmosphere.

[0004] In some examples, a sealed fuel tank for a PHEV includes a steel tank. However, a steel tank adds weight to the vehicle, which may negatively impact battery life and / or fuel economy. Therefore, to reduce vehicle weight and improve fuel economy, future PHEV fuel tanks may be made of plastic. To provide structural integrity to such tanks, structural supports may be placed within the plastic tank. However, these supports may degrade. The inventors herein have recognized this problem and have developed systems and methods to address it. In one example, a method includes: sealing a fuel tank of a vehicle being diagnosed; retrieving fuel tank pressure data from a group of related vehicles; and, in response to the fuel tank pressure data from the group not being sufficiently correlated with the fuel tank pressure data set from the vehicle being diagnosed, indicating that the fuel tank of the vehicle being diagnosed is degraded. This allows determining whether the fuel tank of the vehicle being diagnosed is degraded without connecting the fuel tank to the atmosphere, which can reduce the chance of undesirable evaporative emissions being released into the atmosphere during diagnosis.

[0005] In one example, retrieving fuel tank pressure related data from the fleet of vehicles may include wirelessly retrieving data from the fleet of vehicles via a controller of the diagnosed vehicle.

[0006] In some examples, the method may further include testing to determine whether unwanted evaporative emissions are present from the fuel tank of the diagnosed vehicle before retrieving the fuel tank pressure related data from the vehicle group, and may include retrieving the fuel tank pressure related data from the vehicle group in response to an indication that unwanted evaporative emissions are not present from the fuel tank of the diagnosed vehicle, wherein retrieving the fuel tank pressure related data from the vehicle group further includes a key-off status of the diagnosed vehicle.

[0007] In some examples of this method, the vehicle group may include vehicles of a similar make / model to the diagnosed vehicle, vehicles with sealed fuel tanks, vehicles with fuel levels within a predetermined fuel level range, vehicles that have not been operated for a threshold key-off duration, and / or vehicles within a predetermined distance of the diagnosed vehicle. For example, the predetermined fuel level range may include fuel levels within a threshold fuel level of the fuel level indicated for the diagnosed vehicle.

[0008] In some examples of the method, the fuel tank pressure related data from the vehicle group may include one or more data sets including fuel tank pressure data and one or more data sets including fuel level data from fuel tanks of vehicles comprising the vehicle group, and wherein the fuel tank pressure related data sets from the diagnosed vehicle include a fuel level data set from the diagnosed vehicle and a fuel tank pressure data set from the diagnosed vehicle.

[0009] In some examples of the method, the fuel tank pressure related data from the group of vehicles is not sufficiently correlated with the fuel tank pressure related data set from the diagnosed vehicle includes an indication that the fuel tank pressure related data from the group of vehicles is not within a predetermined threshold of the fuel tank pressure related data set from the diagnosed vehicle.

[0010] In some examples of the method, retrieving fuel tank pressure related data from the fleet of vehicles includes retrieving fuel tank pressure related data from the fleet of vehicles within a predetermined time period, the time period containing a maximum and / or minimum temperature of a diurnal cycle.

[0011] In some examples of the method, the method may further include taking a mitigating action in response to the indication of degradation of the fuel tank of the diagnosed vehicle. For example, the mitigating action may include fluidly coupling the fuel tank to a fuel vapor storage canister located in an evaporative emissions system of the vehicle; and wherein the fuel tank and the fuel vapor storage canister are further fluidly coupled to atmosphere.

[0012] In some examples of the method, indicating that the fuel tank of the diagnosed vehicle is degraded includes indicating that one or more structural supports in the fuel tank are degraded or not functioning as expected. In some examples, the fuel tank of the vehicle may be plastic, and the vehicle may include a hybrid vehicle, such as a hybrid electric vehicle.

[0013] Another example of a method may include, in response to a condition being met while performing a fuel tank diagnostic on a diagnosed vehicle regarding whether one or more structural supports configured to provide structural integrity to the fuel tank are functioning as expected: sealing the fuel tank of the diagnosed vehicle; sending a wireless request from a controller of the diagnosed vehicle to one or more vehicles; selecting, by the controller of the diagnosed vehicle, a group of vehicles from the one or more vehicles from which to retrieve information regarding fuel tank pressure; wirelessly retrieving the information regarding fuel tank pressure from the group of vehicles; also retrieving a dataset regarding fuel tank pressure from the diagnosed vehicle, and subsequently comparing the information regarding fuel tank pressure from the group of vehicles; and in response to the information regarding fuel tank pressure from the group of vehicles not correlating with the dataset regarding fuel tank pressure from the diagnosed vehicle, indicating degradation of one or more of the one or more structural supports of the diagnosed vehicle.

[0014] In an example of this method, conditions being met for performing the fuel tank diagnostic may include a key-off state of the diagnosed vehicle, a time since key-off being greater than a threshold duration, and / or an indication that undesirable evaporative emissions are absent from the fuel tank of the diagnosed vehicle.

[0015] In another example of this method, selecting the vehicle group may include excluding from the vehicle group vehicles that are a different make / model than the diagnosed vehicle, excluding from the vehicle group vehicles that do not have a sealed fuel tank, excluding from the vehicle group vehicles that have a fuel level that is not within a predetermined fuel level range, and excluding from the vehicle group vehicles that have not been deactivated or out of service for a threshold key-off duration.

[0016] In another example of this method, after sealing the fuel tank of the diagnosed vehicle and before sending the wireless request from the controller of the diagnosed vehicle to one or more vehicles, the controller of the diagnosed vehicle is put into sleep mode, and the controller of the diagnosed vehicle can be awakened at a predetermined time point near the maximum temperature of a daily cycle or the minimum temperature of the daily cycle to select the group of vehicles to retrieve information about the fuel tank pressure from the group of vehicles and also retrieve a data set about the fuel tank pressure from the diagnosed vehicle.

[0017] In another example of this method, the method may further include taking mitigating action in response to the indication of one or more degradation in the one or more structural supports of the diagnosed vehicle. For example, taking mitigating action may include: unsealing the fuel tank of the diagnosed vehicle to fluidly couple the fuel tank to atmosphere; capturing fuel vapor from the fuel tank of the diagnosed vehicle in a fuel vapor storage canister located in an evaporative emissions system of the diagnosed vehicle; and, in response to the fuel tank being fluidly coupled to the fuel vapor storage canister, updating a schedule for purging the fuel vapor storage canister to more frequently purge fuel vapor from the fuel vapor storage canister.

[0018] A system for a hybrid vehicle may include: a fuel tank selectively fluidly coupled to a fuel vapor canister via a conduit; a fuel tank isolation valve located within the conduit between the fuel tank and the fuel vapor canister and configured to seal the fuel tank from the fuel vapor canister and atmosphere when closed; a fuel tank pressure sensor (FTPT) located in a vapor recovery line between the fuel tank and the fuel tank isolation valve; a fuel level indicator located in the fuel tank of the hybrid vehicle; a wireless communication device; and a controller. The controller may be configured with instructions stored in a non-volatile memory that, when executed, cause the controller to: seal the fuel tank; wirelessly retrieve weather forecast data to the controller to determine a maximum and minimum temperature corresponding to a current diurnal cycle; schedule a predetermined time to wake the controller near the maximum or minimum temperature; and, after the scheduled time to wake the controller, place the controller into hibernation. At the predetermined time, the controller may be awakened to perform fuel tank diagnostics on the fuel tank of the hybrid vehicle. The fuel tank diagnostic may be performed by retrieving fuel tank pressure data and fuel level data from a group of vehicles within a predetermined distance of the hybrid vehicle, retrieving a fuel tank pressure dataset and a fuel level dataset from the hybrid vehicle, and comparing the fuel tank pressure data and fuel level data from the group of vehicles with the fuel tank pressure dataset and fuel level dataset from the hybrid vehicle. Thus, in response to the fuel tank pressure data and fuel level data from the group of vehicles not correlating or not correlating sufficiently with the fuel tank pressure dataset and fuel level dataset, respectively, an indication may be given as to whether the fuel tank of the hybrid vehicle is degraded. To prevent further degradation of the fuel tank, mitigating action may be taken, including fluidly coupling the fuel tank of the hybrid vehicle to the fuel vapor canister and atmosphere.

[0019] In such a system, the system may further include a temperature sensor located in the fuel vapor canister and configured to indicate a canister load state based on a temperature change within the fuel vapor canister. Additionally, the controller may store further instructions to update a purge schedule for the fuel vapor canister to purge the fuel vapor canister in response to an indication that the canister load state is greater than a threshold load state.

[0020] In such a system, the controller may store further instructions to indicate that the fuel tank of the hybrid vehicle is degraded in response to the fuel tank pressure data and fuel level data from the group of vehicles not correlating (or not sufficiently correlating) with the fuel tank pressure dataset and fuel level dataset, wherein the not correlating (or not sufficiently correlating) includes the fuel tank pressure data from the group of vehicles differing from the fuel tank pressure dataset from the hybrid vehicle by more than 5%, and / or the fuel level data from the group of vehicles differing from the fuel level dataset from the hybrid vehicle by more than 5%.

[0021] The above advantages and other advantages and features of the present specification will become apparent from the following detailed description when read alone or in conjunction with the accompanying drawings.

[0022] It should be understood that the foregoing summary is provided to introduce, in simplified form, a range of concepts further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is solely defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A high-level block diagram illustrating an exemplary vehicle system is shown.

[0024] Figure 2 An exemplary vehicle system having a fuel system and an evaporative emissions system is schematically illustrated.

[0025] Figure 3 Systems and methods for determining whether a structural support in a vehicle fuel tank is degraded using vehicle-to-vehicle (V2V) or vehicle-to-infrastructure-to-vehicle (V2I2V) technology are schematically illustrated.

[0026] Figure 4 A high-level flow chart depicts an example method for testing for undesirable evaporative emissions from a vehicle's fuel tank while the vehicle is not operating.

[0027] Figure 5A high-level flow chart illustrating an example method for testing for undesirable evaporative emissions from a vehicle's fuel tank while the vehicle is operating with the engine off is shown.

[0028] Figure 6 A high-level flow chart is shown of an example method for testing for undesirable evaporative emissions from a vehicle's fuel tank while the vehicle is operating and the engine is combusting air and fuel.

[0029] Figure 7 A diagram depicting the daily cycle.

[0030] Figure 8 A high-level flow chart depicts an example method for accessing fuel tank diagnostics.

[0031] Figure 9 A high-level flow chart depicts an example method for performing fuel tank diagnostics.

[0032] Figure 10 A high-level flow chart depicts an example method for performing a fuel vapor canister purge operation.

[0033] Figure 11 Schematically shows the Figures 8 and 9 An example timeline of the method for performing fuel tank diagnostics is shown. DETAILED DESCRIPTION

[0034] The following description relates to systems and methods for performing fuel tank diagnostics to indicate whether a vehicle's fuel tank has degraded. More specifically, the fuel tank diagnostics can provide an indication of whether one or more structural mounts in the vehicle's fuel tank have degraded or are not functioning as expected. Such diagnostics can be performed while the fuel tank of the vehicle being diagnosed (VD) remains sealed, thereby reducing the chance of unwanted evaporative emissions (e.g., hydrocarbon emissions) being released into the atmosphere. Thus, in hybrid vehicles (e.g., where engine operating time is limited and the fuel tank is sealed under normal vehicle operating conditions) Figure 1 In hybrid vehicles such as the one shown in FIG. 1 , such a diagnosis can be performed. The fuel tank of such a vehicle can be sealed by a fuel tank isolation valve, such as Figure 2 A fuel tank isolation valve may seal the fuel tank from an evaporative emissions system, which may include a fuel vapor storage canister.

[0035] Fuel tank diagnosis can be performed by obtaining information related to fuel tank pressure and fuel level from vehicles constituting the vehicle group, such as Figure 3 To make the diagnosis more reliable, it is first possible to determine whether there are unwanted evaporative emissions originating from the VD fuel tank. Figures 4 to 6An example method for determining whether a source of unwanted evaporative emissions is present in a fuel tank in a vehicle having a sealed fuel tank is described. In response to an indication that the fuel tank is not generating unwanted evaporative emissions (e.g., there are no unwanted evaporative emissions), and further in response to conditions for performing a fuel tank diagnostic being met, the fuel tank diagnostic may include wirelessly communicating with a fleet of vehicles to retrieve fuel tank pressure and fuel level data. In one example, Figure 7 As shown, the VD controller can obtain the fuel tank pressure and fuel level data at the highest or lowest temperature of the daily cycle. Figure 8 An example method for accessing fuel tank diagnostics is depicted, and Figure 9 An example method for performing fuel tank diagnostics is depicted. In some examples, in response to an indication of fuel tank degradation by a VD, mitigating actions may be taken, such as coupling the fuel tank to a fuel vapor storage canister. Such actions may therefore result in a desire to purge the canister of fuel tank vapors more frequently, and accordingly, Figure 10 A method of purging a VD fuel vapor storage canister is shown. Figure 11 An example timeline for performing fuel tank diagnostics is shown.

[0036] Figure 1 An exemplary vehicle propulsion system 100 is shown. Vehicle propulsion system 100 includes a fuel-burning engine 110 and a motor 120. As a non-limiting example, engine 110 includes an internal combustion engine, while motor 120 includes an electric motor. Motor 120 may be configured to utilize or consume a different energy source than engine 110. For example, engine 110 may consume a liquid fuel (e.g., gasoline) to produce an engine output, while motor 120 may consume electrical energy to produce a motor output. Therefore, a vehicle having propulsion system 100 may be referred to as a hybrid electric vehicle (HEV).

[0037] Vehicle propulsion system 100 can utilize various different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes can enable engine 110 to be maintained in an off state (i.e., set to a deactivated state), wherein fuel combustion at the engine is stopped. For example, under selected operating conditions, when engine 110 is deactivated, motor 120 can propel the vehicle via drive wheels 130, as indicated by arrow 122.

[0038] During other operating conditions, engine 110 can be set to a deactivated state (as described above), while motor 120 can be operated to charge energy storage device 150. For example, motor 120 can receive wheel torque from drive wheels 130, as indicated by arrow 122, wherein the motor can convert the vehicle's kinetic energy into electrical energy for storage at energy storage device 150, as indicated by arrow 124. This operation can be referred to as regenerative braking of the vehicle. Thus, in some examples, motor 120 can provide a generator function. However, in other examples, generator 160 can alternatively receive wheel torque from drive wheels 130, wherein the generator can convert the vehicle's kinetic energy into electrical energy for storage at energy storage device 150, as indicated by arrow 162.

[0039] Under other operating conditions, engine 110 can operate by burning fuel received from fuel system 140, as indicated by arrow 142. For example, engine 110 can be operated to propel the vehicle via drive wheels 130, as indicated by arrow 112, while motor 120 is deactivated. Under other operating conditions, both engine 110 and motor 120 can be operated independently to propel the vehicle via drive wheels 130, as indicated by arrows 112 and 122, respectively. A configuration in which both the engine and motor can selectively propel the vehicle can be referred to as a parallel vehicle propulsion system. Note that in some examples, motor 120 can propel the vehicle via a first set of drive wheels, and engine 110 can propel the vehicle via a second set of drive wheels.

[0040] In other examples, vehicle propulsion system 100 can be configured as a series vehicle propulsion system, whereby the engine does not directly propel the drive wheels. Instead, engine 110 can be operated to provide power to motor 120, which in turn can propel the vehicle via drive wheels 130, as indicated by arrow 122. For example, during selected operating conditions, engine 110 can drive generator 160, as indicated by arrow 116, which can in turn provide electrical energy to one or more motors 120, as indicated by arrow 114, or to energy storage device 150, as indicated by arrow 162. As another example, engine 110 can be operated to drive motor 120, which can in turn provide generator functionality, converting the engine output into electrical energy, which can be stored in energy storage device 150 for later use by the motor.

[0041] Fuel system 140 may include one or more fuel storage tanks 144 for storing fuel on the vehicle. For example, fuel tank 144 may store one or more liquid fuels, including but not limited to gasoline, diesel, and alcohol fuels. In some examples, fuel may be stored on the vehicle as a mixture of two or more different fuels. For example, fuel tank 144 may be configured to store a mixture of gasoline and ethanol (e.g., E10, E85, etc.) or a mixture of gasoline and methanol (e.g., M10, M85, etc.), whereby these fuels or fuel mixtures may be delivered to engine 110 as indicated by arrow 142. Other suitable fuels or fuel mixtures may also be supplied to engine 110, where they may be combusted to generate engine output. The engine output may be used to propel the vehicle as indicated by arrow 112, or to charge energy storage device 150 via motor 120 or generator 160.

[0042] In some examples, energy storage device 150 may be configured to store electrical energy that may be supplied to other electrical loads on the vehicle (besides the motor), including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, etc. As non-limiting examples, energy storage device 150 may include one or more batteries and / or capacitors.

[0043] Control system 190 can communicate with one or more of engine 110, motor 120, fuel system 140, energy storage device 150, and generator 160. Control system 190 can receive sensory feedback information from one or more of engine 110, motor 120, fuel system 140, energy storage device 150, and generator 160. Furthermore, control system 190 can send control signals to one or more of engine 110, motor 120, fuel system 140, energy storage device 150, and generator 160 in response to the sensory feedback. Control system 190 can receive an indication of an operator-requested vehicle propulsion system output from vehicle operator 102. For example, control system 190 can receive sensory feedback from pedal position sensor 194 in communication with pedal 192. Pedal 192 can illustratively be a brake pedal and / or an accelerator pedal. Furthermore, in some examples, control system 190 can communicate with a remote engine start receiver 195 (or transceiver), which receives wireless signal 106 from key fob 104 having remote start button 105. In other examples (not shown), a remote engine start may be initiated through a cell phone or smartphone-based system where the user's cell phone sends data to a server and the server communicates with the vehicle to start the engine.

[0044] Energy storage device 150 may periodically receive electrical energy from a power source 180 external to the vehicle (e.g., not part of the vehicle), as indicated by arrow 184. As a non-limiting example, vehicle propulsion system 100 may be configured as a plug-in hybrid electric vehicle (PHEV), whereby electrical energy may be supplied from power source 180 to energy storage device 150 via power transmission cable 182. During operation of charging energy storage device 150 from power source 180, transmission cable 182 may electrically couple energy storage device 150 with power source 180. When the vehicle propulsion system is operated to propel the vehicle, transmission cable 182 may disconnect power source 180 from energy storage device 150. Control system 190 may identify and / or control the amount of electrical energy stored at the energy storage device, which may be referred to as a state of charge (SOC).

[0045] In other examples, transmission cable 182 may be omitted, where electrical energy may be wirelessly received from power source 180 at energy storage device 150. For example, energy storage device 150 may receive electrical energy from power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. Thus, it should be understood that energy storage device 150 may be charged using any suitable method from a power source that is not part of the vehicle. In this manner, motor 120 may propel the vehicle using an energy source other than the fuel used by engine 110.

[0046] Fuel system 140 can periodically receive fuel from a fuel source external to the vehicle. As a non-limiting example, vehicle propulsion system 100 can be refueled by receiving fuel via fuel dispensing device 170, as indicated by arrow 172. In some examples, fuel tank 144 can be configured to store fuel received from fuel dispensing device 170 until it is supplied to engine 110 for combustion. In some examples, control system 190 can receive an indication of the level of fuel stored at fuel tank 144 via a fuel level sensor. The level of fuel stored at fuel tank 144 (e.g., as identified by the fuel level sensor) can be communicated to the vehicle operator, for example, via a fuel gauge or indicator in vehicle instrument panel 196.

[0047] The vehicle propulsion system 100 may also include an ambient temperature / humidity sensor 198 and roll stability control sensors, such as lateral and / or longitudinal and / or yaw rate sensors 199. The vehicle instrument panel 196 may include one or more indicator lights and / or a text-based display in which messages are displayed to the operator. The vehicle instrument panel 196 may also include various input portions for receiving operator input, such as buttons, a touch screen, voice input / recognition, etc. For example, the vehicle instrument panel 196 may include a refuel button 197 that can be manually actuated or pressed by the vehicle operator to initiate refueling. For example, in response to the vehicle operator actuating the refuel button 197, the fuel tank in the vehicle may be depressurized, thereby allowing refueling.

[0048] In some examples, vehicle propulsion system 100 may include one or more onboard cameras 135. For example, onboard cameras 135 may transmit photographic and / or video images to control system 190. For example, in some examples, onboard cameras may be used to record images within a predetermined radius of the vehicle.

[0049] As is known in the art, control system 190 can be communicatively coupled to other vehicles or infrastructure using appropriate communication technologies. For example, control system 190 can be coupled to other vehicles or infrastructure via wireless network 131, which can include Wi-Fi, Bluetooth, a type of cellular service, a wireless data transmission protocol, and the like. Using vehicle-to-vehicle (V2V), vehicle-to-infrastructure-to-vehicle (V2I2V), and / or vehicle-to-infrastructure (V2I or V2X) technologies, control system 190 can broadcast (and receive) information regarding vehicle data, vehicle diagnostics, traffic conditions, vehicle location information, vehicle operating procedures, and the like. Communication and information exchange between vehicles can be direct or multi-hop. In some examples, longer-range communications (e.g., WiMax) can be used in place of or in addition to V2V or V2I2V to extend coverage by several miles. In other examples, vehicle control system 190 can be communicatively coupled to other vehicles or infrastructure via wireless network 131 and the internet (e.g., the cloud), as is known in the art.

[0050] The vehicle system 100 may also include an onboard navigation system 132 (e.g., a global positioning system) with which the vehicle operator can interact. The navigation system 132 may include one or more position sensors to help estimate vehicle speed, vehicle altitude, vehicle position / location, etc. This information may be used to infer engine operating parameters, such as local atmospheric pressure. As described above, the control system 190 may be further configured to receive information via the Internet or other communication networks. Information received from the GPS may be cross-referenced with information available via the Internet to determine local weather conditions, local vehicle regulations, etc.

[0051] Figure 2 FIG2 shows a schematic diagram of a vehicle system 206. It is understood that the vehicle system 206 may constitute the above Figure 1 The vehicle system 206 is the same as the vehicle propulsion system 100 shown. The vehicle system 206 includes an engine system 208 coupled to an evaporative emission control (Evap) system 251 and a fuel system 218. It is understood that the fuel system 218 can be configured similarly to the above Figure 1 The vehicle system 206 may be a hybrid electric vehicle (HEV) system or a plug-in hybrid electric vehicle (PHEV) system.

[0052] The engine system 208 may include an engine 110 having a plurality of cylinders 230. The engine 110 includes an engine intake system 223 and an engine exhaust system 225. The engine intake system 223 includes a throttle valve 262 fluidly coupled to an engine intake manifold 244 via an intake passage 242. The engine exhaust system 225 includes an exhaust manifold 248 leading to an exhaust passage 235, which directs exhaust gas to the atmosphere. The engine exhaust system 225 may include one or more exhaust catalysts 270, which may be mounted in a close-coupled position in the exhaust. The exhaust catalyst may include a temperature sensor 279. In some examples, one or more emission control devices may include a three-way catalyst, a lean NOx trap, a diesel particulate filter, an oxidation catalyst, etc. It will be appreciated that other components may be included in the engine, such as various valves and sensors.

[0053] An intake system hydrocarbon trap (AIS HC) 224 may be placed in the intake manifold of engine 110 to adsorb fuel vapors emitted from unburned fuel in the intake manifold, fuel seepage from leaking injectors, and / or fuel vapors from crankcase ventilation emissions during engine shutdown. The AIS HC may comprise a stack of sequentially layered polymer sheets impregnated with an HC vapor adsorption / desorption material. Alternatively, the adsorption / desorption material may be filled in the areas between the polymer layers. The adsorption / desorption material may comprise one or more of carbon, activated carbon, zeolite, or any other HC adsorption / desorption material. When the engine is running, inducing intake manifold vacuum and generating airflow through the AIS HC, the trapped vapors are passively desorbed from the AIS HC and combusted in the engine. Thus, during engine operation, intake fuel vapors are stored and desorbed from the AIS HC 224. Furthermore, fuel vapors stored during engine shutdown may also be desorbed from the AIS HC during engine operation. In this way, the AIS HC 224 may be continuously loaded and purged, and the trap may reduce evaporative emissions from the intake tract even when the engine 110 is stopped.

[0054] The fuel system 218 may include a fuel tank 220 coupled to a fuel pump system 221. It will be appreciated that the fuel tank 220 may be configured similarly to the above Figure 1 The fuel tank 220 is the same as the fuel tank shown. The fuel pump system 221 may include one or more pumps for pressurizing fuel delivered to the injectors of the engine 110 (such as the example injector 266 shown). Although only a single injector 266 is shown, additional injectors are provided for each cylinder. It should be understood that the fuel system 218 can be a returnless fuel system, a return fuel system, or various other types of fuel systems. The fuel tank 220 can accommodate a variety of fuel mixtures, including fuels with a certain range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, etc. and combinations thereof. The fuel level sensor 234 located in the fuel tank 220 can provide an indication of the fuel level ("fuel level input") to the controller 212, where the controller 212 is a component of the control system 214. It will be understood that the control system 214 can be configured as described above. Figure 1 The same control system as shown in the control system 190. As shown, the fuel level sensor 234 may include a float connected to a variable resistor. Alternatively, other types of fuel level sensors may be used.

[0055] In the examples described herein, it is understood that the fuel tank 220 may comprise a plastic fuel tank. Accordingly, in order to provide structural integrity to the fuel tank, one or more structural supports 293 may be positioned in the fuel tank 220. As will be discussed in detail below, there may be instances where a structural support degrades. Ideally, it would be desirable to provide a system and method for inferring whether a structural support has degraded. Figures 4 to 6 and Figures 8 and 9 Discuss this approach.

[0056] Vapors generated in fuel system 218 may be routed to Evap system 251, including fuel vapor canister 222, via vapor recovery line 231 before being purged into engine air intake 223. Vapor recovery line 231 may be coupled to fuel tank 220 via one or more conduits and may include one or more valves for isolating the fuel tank under certain conditions. For example, vapor recovery line 231 may be coupled to fuel tank 220 via one or more of conduits 271, 273, and 275, or a combination thereof.

[0057] Furthermore, in some examples, one or more fuel tank vent valves may be located in conduits 271, 273, or 275. Among other functions, the fuel tank vent valves may allow the fuel vapor canister of the emission control system to maintain a low pressure or vacuum without increasing the fuel evaporation rate in the fuel tank (which would otherwise occur if the fuel tank pressure were to decrease). For example, conduit 271 may include a gradient vent valve (GVV) 287, conduit 273 may include a fill limit vent valve (FLVV) 285, and conduit 275 may include a gradient vent valve (GVV) 283. Furthermore, in some examples, recycle line 231 may be coupled to fuel fill system 219. In some examples, the fuel fill system may include a fuel tank cap 205 for sealing the fuel fill system from the atmosphere. Fuel replenishment system 219 is coupled to fuel tank 220 via fuel fill pipe or neck 211.

[0058] In addition, the fuel replenishment system 219 may include a fuel replenishment lock 245. In some embodiments, the fuel replenishment lock 245 may be a fuel tank cap locking mechanism. The fuel tank cap locking mechanism may be configured to automatically lock the fuel tank cap in a closed position, preventing it from being opened. For example, when the pressure or vacuum in the fuel tank is greater than a threshold, the fuel tank cap 205 may remain locked by the fuel replenishment lock 245. In response to a fuel replenishment request, such as one initiated by the vehicle operator, the fuel tank may be depressurized, and the fuel tank cap may be unlocked after the pressure or vacuum in the fuel tank drops below the threshold. The fuel tank cap locking mechanism may be a latch or clutch device that, when engaged, prevents the fuel tank cap from being removed. The latch or clutch device may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0059] In some embodiments, refuel lock 245 may be a filler pipe valve located at the mouth of fuel filler pipe 211. In such embodiments, refuel lock 245 may not prevent removal of fuel tank cap 205. Instead, refuel lock 245 may prevent insertion of a refuel pump into fuel filler pipe 211. The filler pipe valve may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0060] In some embodiments, the refueling lock 245 can be a refueling door lock, such as a latch or clutch that locks a refueling door located in a vehicle body panel. The refueling door lock can be locked electrically, such as by a solenoid, or mechanically, such as by a pressure diaphragm.

[0061] In an embodiment where an electrical mechanism is used to lock the refuel lock 245, the refuel lock 245 can be unlocked by a command from the controller 212, for example, when the fuel tank pressure drops below a pressure threshold. In an embodiment where a mechanical mechanism is used to lock the refuel lock 245, the refuel lock 245 can be unlocked by a pressure gradient, for example, when the fuel tank pressure drops to atmospheric pressure.

[0062] As discussed, the Evap system 251 may include one or more emission control devices, such as one or more fuel vapor canisters 222 filled with a suitable adsorbent. These canisters are configured to temporarily capture fuel vapors (including evaporated hydrocarbons) during fuel tank filling operations, running losses (i.e., fuel evaporated during vehicle operation), and during the diurnal cycle. In one example, the adsorbent used is activated carbon. The Evap system 251 may further include a canister vent path or vent line 227 that vents gases from the canister 222 to the atmosphere while storing or capturing fuel vapors from the fuel system 218.

[0063] Canister 222 may include a buffer 222a (or buffer area), each of which includes an adsorbent. As shown, the volume of buffer 222a may be smaller than the volume of canister 222 (e.g., a portion thereof). The adsorbent in buffer 222a may be the same as or different from the adsorbent in the canister (e.g., both may include charcoal). Buffer 222a may be located within canister 222 such that during canister loading, fuel tank vapors are first adsorbed within the buffer, and then, as the buffer becomes saturated, more fuel tank vapors are adsorbed within the canister. In contrast, during canister purging, fuel vapors are first desorbed from the canister (e.g., until a threshold amount is reached) and then desorbed from the buffer. In other words, the loading and unloading of the buffer is not linear with the loading and unloading of the canister. Therefore, the canister buffer serves to suppress any surge in fuel vapors flowing from the fuel tank to the canister, thereby reducing the likelihood that any surge in fuel vapors will reach the engine. One or more temperature sensors 232 may be coupled to and / or within canister 222. When fuel vapor is adsorbed by the adsorbent in the canister, heat (adsorption heat) is generated. Similarly, when fuel vapor is desorbed from the adsorbent in the canister, heat is dissipated. This allows monitoring and estimation of the adsorption and desorption of fuel vapor from the canister based on temperature changes within the canister.

[0064] Vent line 227 may also allow fresh air to be drawn into canister 222 while purging stored fuel vapors from fuel system 218 via purge line 228 and purge valve 261 to engine intake system 223. For example, purge valve 261 may be normally closed but may be opened under certain conditions to allow vacuum from engine intake manifold 244 to be provided to the fuel vapor canister for purging. In some examples, vent line 227 may include an air filter 259 positioned upstream of canister 222.

[0065] In some examples, the flow of air and vapors between canister 222 and the atmosphere can be regulated by a canister vent valve (CVV) 297 coupled within vent line 227. When included, the canister vent valve can be a normally open valve, allowing fuel tank isolation valve 252 (FTIV) to control venting of fuel tank 220 to the atmosphere. FTIV 252 can be located within conduit 278 between the fuel tank and the fuel vapor canister. FTIV 252 can be a normally closed valve that, when open, allows fuel vapors to pass from fuel tank 220 to canister 222. The fuel vapors can then be vented to the atmosphere via CVV 297 or purged into engine air intake 223 via canister purge valve 261.

[0066] Fuel system 218 may be operated in a variety of modes by controller 212 by selectively adjusting various valves and solenoids. For example, the fuel system may be operated in a fuel vapor storage mode (e.g., during a fuel tank refueling operation and when the engine is not running), wherein controller 212 may open isolation valve 252 while closing canister purge valve (CPV) 261 to direct fuel refueling vapors into canister 222 while preventing fuel vapors from being directed into the intake manifold.

[0067] As another example, the fuel system can be operated in a refueling mode (e.g., when a vehicle operator requests refueling of the fuel tank), wherein controller 212 can open isolation valve 252 while maintaining canister purge valve 261 closed to depressurize the fuel tank before fuel can be added thereto. Thus, isolation valve 252 can remain open during the refueling operation to allow refueling vapors to be stored in the canister. After refueling is complete, the isolation valve can be closed.

[0068] As another example, the fuel system can be operated in a canister purge mode (e.g., after the emission control device light-off temperature has been reached and with the engine running), where controller 212 can open canister purge valve 261 while closing isolation valve 252. Here, vacuum generated by the intake manifold of the operating engine can be used to draw fresh air through vent line 227 and through fuel vapor canister 222 to purge stored fuel vapors into intake manifold 244. In this mode, the fuel vapors purged from the canister are combusted in the engine. Purging can continue until the amount of fuel vapor stored in the canister falls below a threshold.

[0069] An unwanted evaporative emissions detection routine can be intermittently performed by controller 212 on fuel system 218 and Evap system 251 to confirm that fuel system 218 and Evap system 251 are not emitting unwanted evaporative emissions. Thus, an evaporative emissions test can be performed while the engine is off (engine-off test) using engine-off natural vacuum (EONV) generated due to temperature and pressure changes at the fuel tank after the engine is shut down. For example, in response to an engine-off event, the fuel system can be isolated and the pressure in the fuel system can be monitored. Identification of unwanted vapor emissions can be indicated based on a pressure rise below a threshold or a rate of pressure rise below a threshold. Additionally, vacuum development can be monitored as the fuel tank cools down, and unwanted vapor emissions can be identified based on vacuum development below a threshold or a rate of vacuum development below a threshold.

[0070] In other examples, the evaporative emissions test procedure can be performed while the engine is running by using engine intake manifold vacuum, or by operating a vacuum pump while the engine is running or during an engine off state. For example, testing for undesirable evaporative emissions can be performed by an evaporative emissions check module (not shown) communicatively coupled to controller 212. The evaporative emissions check module can be coupled in vent line 227, for example, between canister 222 and the atmosphere. The evaporative emissions check module can include a vacuum pump for applying negative pressure to the fuel system when performing the evaporative emissions test. In some embodiments, the vacuum pump can be configured to be reversible. In other words, the vacuum pump can be configured to apply either negative or positive pressure to the fuel system.

[0071] In other examples, the evaporative emissions test routine can be performed while the vehicle is operating, but in an electric-only mode of operation. In such an example, the engine can be rotated without being supplied with fuel, for example by a motor (e.g., 120), to generate intake manifold vacuum, which can be sent to the vehicle fuel system and / or evaporative emissions system to diagnose potential undesirable evaporative emissions. Figures 4 to 6 Discuss these procedures in detail.

[0072] In some configurations, a canister ventilation valve (CVV) 297 may be coupled within vent line 227 . CVV 297 can be used to regulate the flow of air and vapors between canister 222 and the atmosphere. The CVV can also be used for diagnostic procedures. When a CVV is included, the CVV can be opened during fuel vapor storage operations (e.g., during fuel tank refueling and, in some cases, when the engine is not running) so that air removed from the fuel vapors after passing through the canister can be pushed out to the atmosphere. Similarly, during purge operations (e.g., during canister regeneration and when the engine is running), the CVV can be opened to allow fresh air to flow to remove fuel vapors stored in the canister. In some examples, CVV 297 can be a solenoid valve, where opening or closing the valve is performed by actuation of a canister ventilation solenoid. Specifically, the canister ventilation valve can be a default open valve that closes when the canister ventilation solenoid is actuated. In some examples, CVV 297 can be configured as a latchable solenoid valve. In other words, when the valve is in the closed configuration, it latches without requiring additional current or voltage. For example, the valve can be closed with a 100ms pulse and then opened with another 100ms pulse at a later point in time. In this way, the battery power required to maintain the CVV closed is reduced.

[0073] As discussed, the controller 212 may form part of a control system 214, wherein the control system 214 may form part of a control system 214. Figure 1The control system 214 is shown as being the same as the control system 190 shown. Control system 214 is shown receiving information from a plurality of sensors 216 (various examples of which are described herein) and sending control signals to a plurality of actuators 281 (various examples of which are described herein). As one example, sensors 216 may include exhaust gas sensor 237 located upstream of the emission control device, temperature sensor 233, pressure sensor 291 (fuel tank pressure sensor), mass air flow (MAF) sensor 282, atmospheric pressure sensor 213, fuel tank temperature sensor 288, and canister temperature sensor 232. Other sensors such as pressure sensors, temperature sensors, air-fuel ratio sensors, and composition sensors may be coupled to various locations within vehicle system 206. As another example, actuators may include fuel injector 266, throttle 262, fuel tank isolation valve 252, CPV 261, CVV 297, and refuel lock 245. Controller 212 may receive input data from the various sensors, process the input data, and trigger actuators in response to the processed input data based on instructions or code programmed therein corresponding to one or more routines. This article refers to Figures 4 to 6 and Figures 8 to 10 Additionally, the controller 212 may receive data from the navigation system 132 (e.g., GPS) and / or a V2X network, including a V2V network (vehicle-to-vehicle), a V2I network (vehicle-to-infrastructure), or a V2I2V (vehicle-to-infrastructure-to-vehicle), as described above with respect to Figure 1 The network 131 discussed. For example, the wireless communication device 280 can be coupled to the vehicle controller 212 for implementing wireless communication.

[0074] In some examples, the controller can be placed in a reduced power mode or sleep mode, in which the controller maintains only basic functionality and operates with lower battery consumption than a corresponding awake mode. For example, the controller can be placed in sleep mode after a vehicle shutdown event to perform diagnostic routines for a period of time after the vehicle shutdown event. The controller can have a wake-up input that allows the controller to return to awake mode based on input received from one or more sensors. In some examples, the controller can schedule a wake-up time, which can include setting a timer, and when the timer expires, the controller can wake up from sleep mode.

[0075] Now go to Figure 3, depicts an exemplary diagram 300 detailing how a vehicle undergoing fuel tank diagnostics (referred to herein as a diagnosed vehicle, or VD) may obtain fleet information comprising one or more fuel tank pressure and / or fuel level related data sets in vehicles similar to the diagnosed vehicle in order to determine whether a structural support (e.g., 293) in the VD's fuel tank (e.g., 220) is degraded. Thus, degradation of the structural support may be diagnosed without venting the fuel tank and without using an onboard pump, as will be discussed in further detail below. For example, such fleet information may be obtained by the VD via one or more of a vehicle-to-vehicle (V2V) network or a vehicle-to-infrastructure-to-vehicle (V2I2V) network. Accordingly, Figure 3 A vehicle to be diagnosed (VD) 310 is shown in wireless communication 312 with a number of other vehicles 315, wherein the diagnosis is for degradation of its structural supports. It will be appreciated that the vehicle 310 may be composed of Figure 1 The vehicle propulsion system 100 and / or Figure 2 The same vehicle as shown in the vehicle system 206. Vehicle 310 may include a control system 214, which includes a controller 212, as described above with respect to Figure 2 As discussed, wireless communication device 280 can be coupled to controller 212 for enabling wireless communication between vehicle 310 and vehicle 315. Additionally, vehicle 310 can include navigation device 132 (e.g., GPS), which can be configured to receive information via GPS satellites 323.

[0076] Control system 214 is shown receiving information from a plurality of sensors 216 and sending control signals to a plurality of actuators 218. As discussed, sensors 216 may include a barometric pressure sensor (e.g., 213), a mass air flow sensor (e.g., 282), a fuel vapor canister temperature sensor (e.g., 232), exhaust gas sensors (e.g., 237), an exhaust catalyst temperature sensor (e.g., 279), an FTPT (e.g., 291), a fuel tank temperature sensor (e.g., 288), a fuel level sensor (e.g., 234), and an ambient temperature / humidity sensor (e.g., 198). Based on the sensors in vehicle 310, various information may be indicated, such as whether the vehicle is running, an estimated time since the vehicle was last running, ambient temperature / humidity near the vehicle, pressure in the fuel tank, fuel level, etc. Furthermore, in some examples, an onboard camera (e.g., 135) may be used to indicate whether the vehicle is running, the environment in which the vehicle is parked (e.g., shade, direct sunlight, etc.), the vehicle's location, etc.

[0077] Although not explicitly shown, it is understood that other vehicles 315 may also include the components described for vehicle 310. For example, vehicle 315 may similarly include a control system having a controller that receives information from a plurality of sensors and wherein commands may be sent from the controller to a plurality of actuators. In addition, vehicle 315 may include wireless communication devices for sending and receiving wireless communications between vehicles or infrastructure.

[0078] Vehicle 310 may wirelessly transmit and retrieve information via V2V or V2I2V technology with vehicles 315 that are within a predetermined distance or radius 320 from vehicle 310. For example, vehicles 327 (wherein vehicles 327 are a subset of vehicles 315) may be excluded, i.e., information may not be retrieved from these vehicles, because they are outside predetermined distance 320 from vehicle 310. In some examples, the predetermined distance may be set such that the vehicle from which information / data is to be retrieved is likely to experience similar weather conditions, such as ambient temperature / humidity, etc., when the vehicle is being diagnosed (e.g., 310).

[0079] Among the vehicles within a predetermined distance 320 from the vehicle to be diagnosed 310, it can be further determined from which vehicles the one or more data sets are to be retrieved. In other words, among the vehicles within a predetermined distance 320 from the vehicle to be diagnosed 310, only a subset of these vehicles can constitute a selected vehicle group or vehicle group 324, from which one or more data sets are to be obtained and utilized in order to diagnose whether a structural support (e.g., 293) in the vehicle 310 is degraded. Figures 8 and 9 The illustrated method details how such a cluster 324 may be formed. Briefly, the selection criteria for the cluster 324 may be based on vehicle make / model (e.g., a make / model similar to the diagnosed vehicle), whether the vehicle's fuel tank comprises a sealed fuel tank, a fuel level within a predetermined fuel level range, whether the vehicle is near structures that may affect the temperature / environmental conditions experienced by the vehicle, whether the vehicle is in a key-off state, the time since key-off, a fuel tank temperature within a predetermined fuel tank temperature range, the engine operating time prior to the key-off event, etc. Thus, vehicles within the predetermined distance 320 that are not identified as forming part of the selected cluster 324 may be referred to as excluded vehicles 329.

[0080] After identifying the selected vehicle group 324, vehicle 310 may retrieve one or more data sets including fuel tank pressure and fuel level-related information from vehicle 315 via V2V or V2I2V technology. In one example, fuel tank pressure data may be obtained from vehicle 315. More specifically, it will be appreciated that for vehicles with sealed fuel tanks, temperature fluctuations throughout a 24-hour period (e.g., a diurnal cycle) may cause pressure / temperature variations within such sealed fuel tanks. Therefore, in some examples, fuel tank pressure data from the vehicles comprising the selected vehicle group may be retrieved at predetermined points in the diurnal cycle (e.g., the highest or lowest temperature of the diurnal cycle). For example, at the highest and / or lowest temperatures of the diurnal cycle, the fuel tank pressures of the fuel tanks comprising the selected vehicle group 324 may be retrieved by vehicle 310. The controller of vehicle 310 may then average the fuel tank pressure data corresponding to the highest or lowest temperatures to obtain an average highest or lowest fuel tank pressure for the selected vehicle group 324. This information regarding the direction (e.g., positive pressure relative to atmosphere or negative pressure relative to atmosphere) and magnitude of the fuel tank pressure corresponding to the selected vehicle group 324 can then be compared (by the controller of the vehicle 310) with data obtained regarding the fuel tank pressure of the diagnosed vehicle 310. If the fuel tank pressure data obtained from the diagnosed vehicle 310 correlates with the fuel tank pressure data obtained from the selected vehicle group 324, it can be determined that the structural support (e.g., 293) is functioning as expected. In such an example, the fuel tank pressure data from the selected vehicle group 324 and the fuel tank pressure data from the diagnosed vehicle 310 "correlating" can include the fuel tank pressure data from the diagnosed vehicle 310 being within a predetermined threshold (e.g., within 5% or less) of the vehicles comprising the selected vehicle group. However, if the fuel tank pressure in the diagnosed vehicle 310 does not correlate with the fuel tank pressure data obtained from the selected vehicle group 324 (e.g., differs by more than 5%), it can be determined that the structural support in the diagnosed vehicle may be degraded.

[0081] In some examples, the one or more data sets retrieved from the selected fleet 324 may additionally include the fuel level in the fuel tank of each vehicle comprising the selected fleet 324. For example, if the fuel level in the diagnosed vehicle is abnormal or fluctuates over a predetermined time period compared to the average fuel level for the vehicles comprising the selected fleet, structural support degradation in the diagnosed vehicle may be determined. In the above example, "abnormal or fluctuating" may include a fuel level change in the diagnosed vehicle of 5% or greater (in either direction, e.g., increasing or decreasing the fuel level) compared to the average fuel level for the vehicles comprising the selected fleet. In such an example, fuel level measurements may be retrieved from the vehicles comprising the selected fleet over a predetermined duration or time period and then compared to fuel level measurements retrieved from the diagnosed vehicle 310 recorded over the same predetermined time period. In such an example, the predetermined time period may include a specified amount of time around the highest and / or lowest temperatures of the daily cycle. More specifically, the predetermined time period may include 15 to 30 minutes, 30 minutes to 1 hour, greater than 1 hour but less than 2 hours, or greater than 2 hours but less than 3 hours. By recording the fuel level in the diagnosed vehicle during the predetermined time period and comparing the fuel level with an average fuel level based on data retrieved from a selected fleet of vehicles during the same predetermined time period, it may be determined whether the structural support has deteriorated.

[0082] It is understandable that the above Figure 3 The described method can be applied to vehicles that are in a key-off state and are not being propelled by an onboard energy storage device (e.g., a battery) or the vehicle's engine. For example, if the vehicle is running, even if the engine is not running, driving conditions may cause significant fuel sloshing events in the fuel tank, which may result in pressure variations in the fuel tank. Such pressure variations, influenced by driving conditions, may significantly add a noise factor to any analysis of fuel tank integrity diagnostics based on a fleet of vehicles, making such methods prone to errors. Therefore, it will be understood that the methods described herein relate to vehicles in a key-off state, and not to vehicles in operation.

[0083] Furthermore, in order for such a diagnosis to provide reliable results, the fuel tank of the diagnosed vehicle may be free of unwanted evaporative emissions. For example, if an indication of unwanted evaporative emissions originating from the fuel tank of the diagnosed vehicle is present, the fuel tank may not be maintaining pressure / vacuum, and therefore, the diagnosis discussed above for determining whether a structural support in the fuel tank is degraded may not be reliable. Therefore, there may be several options for determining whether the fuel tank of the diagnosed vehicle is free of unwanted evaporative emissions, as will be discussed below with reference to Figures 4 to 6 discussed.

[0084] Figure 4An example flow chart of a high-level method 400 for performing an evaporative emissions leak test in a hybrid electric vehicle is shown. More specifically, the method 400 describes a method for performing an evaporative emissions leak test without using a vacuum pump and without loading the fuel tank vapors into the fuel vapor canister. Although reference will be made to Figures 1 to 3 Method 400 is described with reference to the system described in

[0045] , but it should be understood that method 400 may be applied to other systems without departing from the scope of this disclosure. Method 400 may be executed by a controller, such as controller 212, and may be stored as executable instructions in a non-volatile memory. Instructions for executing method 400 and the remaining methods included herein may be executed by the controller based on instructions stored on the controller's memory and in conjunction with signals received from sensors of the vehicle system, such as the sensors described above with reference to

[0046] Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emission system actuators, such as the FTIV (eg, 252 ), according to the methods described below.

[0085] Method 400 begins at 405 by evaluating current vehicle operating conditions. Operating conditions may be estimated, measured, and / or inferred, and may include environmental conditions (such as temperature, humidity, barometric pressure, etc.), engine conditions (such as engine operating status, engine speed, engine load, etc.), and fuel system conditions (such as fuel level, fuel tank pressure, fuel vapor canister load status, etc.). Continuing to 410, method 400 may include determining whether the vehicle is in a vehicle-on state. If the vehicle is in a vehicle-on state, method 400 may proceed to 412. At 412, method 400 may include entering a leak test in the vehicle-on state. This document will refer to Figures 5 and 6 An exemplary vehicle-on leak test is further described. Method 400 may then end.

[0086] If the vehicle is not in the vehicle-on state, method 400 may proceed to 415. At 415, method 400 may include determining whether the vehicle wet duration is greater than a threshold. The vehicle wet duration may include the length of time that has elapsed since the most recent vehicle shut-off event. The vehicle wet duration threshold may be predetermined (e.g., 4-6 hours) or may be based on operating conditions. For example, the vehicle wet duration may be based on ambient temperature, changes in ambient temperature during the vehicle wet duration, expected changes in ambient temperature during the vehicle wet duration based on the time of day, heat rejected to the fuel tank during the previous vehicle-on state (which in turn may be based on engine operating conditions during the previous vehicle-on state), etc. As discussed, it will be appreciated that in this example method 400, the fuel tank is sealed by a controller commanding or maintaining the fuel tank isolation valve closed during method 400. Therefore, for such vehicles with isolated fuel tanks, the vehicle wet duration threshold may be based on the expected amount of time required for the fuel tank to experience a threshold temperature change, thereby establishing a positive pressure or vacuum therein. If the vehicle wet duration is less than the threshold, method 400 may proceed to 417. At 417 , method 400 may include maintaining fuel tank isolation for a threshold duration (by maintaining the FTIV closed). The vehicle controller may be placed into a sleep state and reawakened while maintaining the fuel tank isolation valve closed.

[0087] When the vehicle wet engine duration increases above a threshold, method 400 may proceed to 420. At 420, method 400 may include determining whether the absolute fuel tank pressure is greater than a threshold. The absolute fuel tank pressure may be estimated, inferred, or measured, for example, by FTPT 291. The absolute fuel tank pressure threshold may be based on operating conditions, such as ambient atmospheric pressure, ambient temperature, fuel fill level, and fuel composition. The absolute fuel tank pressure threshold may be based on a pressure / vacuum indicative of a healthy fuel tank. In other words, if the fuel tank contains threshold specifications of undesirable evaporative emissions originating from a source within the fuel tank, the threshold pressure / vacuum is unlikely to be reached.

[0088] However, an absolute fuel tank pressure below a threshold does not necessarily indicate degradation. Rather, the fuel tank may be at a zero-crossing point in the diurnal cycle. As ambient temperature rises and falls throughout the diurnal cycle, conditions may arise in the 24-hour cycle where the fuel tank pressure, without undesirable evaporative emissions, does not maintain a pressure or vacuum relative to atmospheric pressure. Thus, if the absolute fuel tank pressure is not greater than the pressure threshold, method 400 may proceed to 422. At 422, method 400 may include placing the controller in hibernation for a period of time and then reawakening the controller. The hibernation duration may be predetermined (e.g., three hours) or may be based on environmental conditions, such as ambient temperature and time of day. The hibernation duration may be based on the length of time over which changes in fuel tank pressure are expected to occur for an intact fuel tank. Continuing at 425, method 400 may include determining whether the absolute fuel tank pressure is greater than a threshold. The absolute fuel tank pressure threshold may be the same as the threshold described at 420 or may be adjusted based on updated current operating conditions, such as ambient temperature and atmospheric pressure. If the absolute fuel tank pressure is not greater than the threshold, method 400 may proceed to 427. At 427, method 400 may include indicating the presence of unwanted evaporative emissions originating from the fuel tank. Indicating the presence of unwanted evaporative emissions may include setting a flag at controller 212 and may further include indicating the degradation to a vehicle user, such as by illuminating a malfunction indicator light (MIL). Proceeding to 435, method 400 may include updating vehicle operating parameters. For example, controller 212 may take mitigating actions based on the presence of unwanted evaporative emissions, such as preventing the vehicle from operating in engine-only mode. Controller 212 may further adjust the evaporative emissions leak test schedule. Method 400 may then end.

[0089] If the absolute fuel tank pressure is greater than the threshold, then at 420 or 425, method 400 may proceed to 430. At 430, method 400 may include indicating the absence of undesirable evaporative emissions. Indicating the absence of undesirable evaporative emissions may further include recording a passing result of the test at controller 212.

[0090] Proceeding to 435 , method 400 may include updating vehicle operating parameters. For example, in response to the indication that there are no undesirable evaporative emissions, the current vehicle operating parameters may be maintained. Method 400 may then end.

[0091] Figure 5 An example flow chart of a high-level method 500 for performing an evaporative emission leak test in a hybrid electric vehicle during a vehicle on state is shown. The method 500 can be performed independently or as a subroutine of another method (such as the method 400). Although reference will be made to Figures 1 to 3Method 500 is described with reference to the system described in

[0045] , but it should be understood that method 500 may be applied to other systems without departing from the scope of this disclosure. Method 500 may be executed by a controller, such as controller 212, and may be stored as executable instructions in a non-volatile memory. Instructions for executing method 500 and the remaining methods included herein may be executed by the controller based on instructions stored on the controller's memory and in conjunction with signals received from sensors of the vehicle system, such as the sensors described above with reference to

[0046] Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emission system actuators, such as CPV (eg, 261 ), FTIV (eg, 252 ), CVV (eg, 297 ), motor (eg, 120 ), etc., according to the methods described below.

[0092] Method 500 begins at 505 by evaluating operating conditions. Operating conditions may be estimated, measured, and / or inferred and may include environmental conditions (such as temperature, humidity, barometric pressure, etc.), engine conditions (such as engine operating status, engine speed, engine load, etc.), and fuel system conditions (such as fuel level, fuel tank pressure, fuel vapor canister load status, etc.). Continuing to 510, method 500 may include determining whether the vehicle is in an engine-on state. If the vehicle is in an engine-on state, method 500 may proceed to 512. At 512, method 500 may include entering a leak test in the engine-on state. This document will refer to Figure 6 An exemplary engine-on leak test is further described. Method 500 may then end.

[0093] If the engine is not on, method 500 may proceed to 515. At 515, method 500 may include determining whether the absolute fuel tank pressure is greater than a threshold, such as Figure 3 As described above. In the example method 500, it is understood that the vehicle fuel tank comprises a sealed fuel tank, wherein the fuel tank is sealed by an FTIV (e.g., 252). If the absolute fuel tank pressure is greater than the threshold, the method 500 may proceed to 517. At 517, the method 500 may include indicating that there are no undesirable evaporative emissions originating from the fuel tank. If it is indicated that there are no undesirable evaporative emissions from the fuel tank, the method 500 may include maintaining the current vehicle operating conditions. The method 500 may then end.

[0094] If at 515, the absolute fuel tank pressure is less than a threshold, method 500 may proceed to 520. At 520, method 500 may include rotating the engine without providing fuel to it to generate engine intake system vacuum. Rotating the engine without providing fuel to it may include operating a motor (e.g., 120) to rotate the engine without providing fuel and spark to the engine cylinders. In response to the engine intake manifold vacuum reaching a threshold intake manifold vacuum, method 500 may proceed to 525. At 525, method 500 may include the controller commanding the CPV to open, commanding the CVV to close, and commanding the FTIV to open. By commanding the FTIV to open, the fuel tank can be fluidly coupled to the evaporative emissions system, and by commanding the CPV to open, the fuel tank (and fuel system) and the evaporative emissions system can be coupled to the engine intake system. Furthermore, by closing the CVV, the fuel system and the evaporative emissions system can be sealed from the atmosphere.

[0095] With the fuel system and the evaporative emissions system sealed from atmosphere and coupled to the engine air intake system, method 500 may proceed to 530. At 530, method 500 may include venting the fuel system and the evaporative emissions system to a threshold negative pressure (e.g., a threshold vacuum), such as monitored by an FTPT (e.g., 291). Although not explicitly shown, it is understood that failure to reach the threshold negative pressure may be due to total undesirable evaporative emissions originating from the fuel system and / or the evaporative emissions system. Therefore, in such a case, method 500 may include indicating the presence of total undesirable evaporative emissions originating from the fuel system and / or the evaporative emissions system.

[0096] In response to reaching a threshold negative pressure in the fuel system and the evaporative emissions system, method 500 may proceed to 535. At 535, method 500 may include sealing the fuel tank and fuel system from the evaporative emissions system. Furthermore, at 535, method 500 may include stopping the engine, which is rotating without a fuel supply, by commanding a motor to stop engine rotation. The fuel tank may be sealed from the evaporative emissions system by the controller signaling the FTIV to close. At 535, method 500 may also include the controller commanding or actuating the closing of the CPV to isolate the engine intake system from the evaporative emissions system. Furthermore, in some examples, the CPV may be commanded to open, thereby releasing vacuum from the evaporative emissions system. With the fuel tank sealed from the evaporative emissions system and engine rotation stopped, method 500 may proceed to 540. At 540, method 500 may include measuring a pressure loss rate, and therefore, may include indicating whether the rate of change of pressure loss in the fuel tank is greater than a predetermined pressure loss rate threshold. If the pressure loss rate of change is greater than the pressure loss rate threshold, method 500 may proceed to 545 and may include indicating the presence of undesirable evaporative emissions from the fuel tank. Figure 4 As discussed, in response to an indication of unwanted evaporative emissions originating from the fuel tank, method 500 may include setting a flag at the controller and may also include illuminating the MIL on the vehicle's instrument panel, alerting the vehicle operator that vehicle service is required. Furthermore, mitigating actions may be taken, such as preventing engine operation if possible, rescheduling the unwanted evaporative emissions test, and so forth. Method 500 may then proceed to 550 and may include relieving the fuel tank vacuum by commanding the FTIV to open for a short period of time, and may then include resealing the fuel tank by commanding the FTIV to close. Method 500 may then end.

[0097] Returning to 540, in response to the pressure loss rate of change being less than the pressure loss rate threshold, method 500 may proceed to 555. At 555, method 500 may include indicating the absence of unwanted fuel tank emissions. In the event that the absence of unwanted fuel tank emissions is indicated, method 500 may include maintaining current vehicle operating parameters. Proceeding to 550, method 500 may include releasing fuel tank vacuum by commanding the FTIV to open, and then resealing the fuel tank by commanding the FTIV to close. Although the method described includes releasing fuel tank vacuum at 550, in some examples, fuel tank vacuum may not be released, and in such examples, the FTIV may remain closed in response to the indication of the presence or absence of unwanted evaporative emissions. Method 500 may then end.

[0098] Figure 6 An example flow chart of a high-level method 600 for performing an evaporative emissions leak test in a hybrid electric vehicle during an engine-on state is shown. The method 600 may be performed independently or as a subroutine of another method, such as the method 400 and / or the method 500. Although reference will be made to Figures 1 to 3 Method 600 is described with reference to the system described in

[0065] , but it should be understood that method 600 may be applied to other systems without departing from the scope of this disclosure. Method 600 may be executed by a controller, such as controller 212, and may be stored as executable instructions in a non-volatile memory. Instructions for executing method 600 and the remaining methods included herein may be executed by the controller based on instructions stored on the controller's memory and in conjunction with signals received from sensors of the vehicle system, such as the sensors described above with reference to

[0066] Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emission system actuators, such as CPV (eg, 261 ), FTIV (eg, 252 ), CVV (eg, 297 ), etc., according to the methods described below.

[0099] Method 600 begins at 605 by evaluating operating conditions. Operating conditions may be estimated, measured, and / or inferred, and may include environmental conditions (such as temperature, humidity, barometric pressure, etc.), engine conditions (such as engine operating state, engine speed, engine load, etc.), and fuel system conditions (such as fuel level, fuel tank pressure, fuel vapor canister load state, etc.). Continuing at 610, method 600 may include determining whether the absolute fuel tank pressure is greater than a threshold, as described above with respect to Figures 4 and 5 If the absolute fuel tank pressure is greater than the threshold at 610, method 600 may proceed to 615. At 615, method 600 may include indicating that there are no undesirable evaporative emissions from the fuel tank. If the absence of undesirable evaporative emissions from the fuel tank is indicated, method 600 may include maintaining the current vehicle operating conditions. Method 600 may then end.

[0100] Returning to 610, if the absolute fuel tank pressure is not greater than the threshold, method 600 may proceed to 620. At 620, method 600 may include determining whether the intake manifold vacuum is greater than the threshold intake manifold vacuum, as described above with respect to Figure 5 As discussed. Intake manifold vacuum may be estimated, inferred, or measured, for example, by a pressure sensor (e.g., 213) in the intake manifold. The threshold intake manifold vacuum may be based on the amount of vacuum required to evacuate the fuel system and the evaporative emissions system. Thus, the intake manifold vacuum threshold may be based on the volume of the fuel system and the evaporative emissions system, and may be further based on fuel level, fuel composition, etc. If the pressure in the intake manifold is not less than the threshold, method 600 may proceed to 625. At 625, method 600 may include continuing to monitor the fuel tank pressure and intake manifold vacuum, and may further include setting a flag to follow up with additional testing to determine if there are unwanted evaporative emissions when the threshold negative pressure is present in the intake manifold.

[0101] Returning to 620 , if the intake manifold vacuum is greater than the intake manifold vacuum threshold (e.g., more negative relative to the threshold pressure), method 600 may proceed to 630 . At 630 , method 600 may include the controller commanding the CPV to open, commanding the CVV to close, and commanding the FTIV to open. By commanding the FTIV to open, the fuel tank may be fluidly coupled to the evaporative emissions system, and by commanding the CPV to open, the fuel tank (and fuel system) and the evaporative emissions system may be coupled to the engine intake system. Furthermore, by closing the CVV, the fuel system and the evaporative emissions system may be sealed from the atmosphere.

[0102] In the event that the fuel system and the evaporative emissions system are sealed from the atmosphere and coupled to the engine intake system, method 600 may proceed to 635. At 635, method 600 may include venting the fuel system and the evaporative emissions system to a threshold negative pressure (e.g., a threshold vacuum), such as monitored by an FTPT (e.g., 291). Although not explicitly shown, it is understood that failure to reach the threshold negative pressure may be due to total undesirable evaporative emissions originating from the fuel system and / or the evaporative emissions system. Therefore, in such a case, method 600 may include indicating the presence of total undesirable evaporative emissions originating from the fuel system and / or the evaporative emissions system.

[0103] In response to reaching a threshold negative pressure in the fuel system and the evaporative emissions system, method 600 may proceed to 640. At 640, method 600 may include sealing the fuel tank and the fuel system relative to the evaporative emissions system (e.g., isolating the fuel system from the evaporative emissions system). The fuel tank may be sealed relative to the evaporative emissions system by sending a signal to the FTIV by the controller to close it. At 640, method 600 may also include the controller commanding or actuating the closure of the CPV to isolate the engine intake system from the evaporative emissions system (and the fuel system). Additionally, in some examples, the CVV may be commanded to open, thereby releasing the vacuum from the evaporative emissions system. With the fuel tank sealed relative to the evaporative emissions system, method 600 may proceed to 645. At 645, method 600 may include measuring a pressure loss rate, and therefore may include indicating whether the rate of change of pressure loss in the fuel tank is greater than a predetermined pressure loss rate threshold. If the rate of change of pressure loss is greater than the pressure loss rate threshold, method 600 may proceed to 650, and may include indicating the presence of unwanted evaporative emissions from the fuel tank. As described above with respect to Figures 4 and 5 As discussed, in response to an indication of unwanted evaporative emissions originating from the fuel tank, method 600 may include setting a flag at the controller and may also include illuminating the MIL on the vehicle's instrument panel, alerting the vehicle operator that vehicle service is required. Furthermore, mitigating actions may be taken, such as preventing engine operation if possible, rescheduling the unwanted evaporative emissions test, and so forth. Method 600 may then proceed to 655 and may include relieving the fuel tank vacuum by commanding the FTIV to open for a short period of time, and may then include resealing the fuel tank by commanding the FTIV to close. Method 500 may then end.

[0104] Returning to 645, in response to the pressure loss rate of change being less than the pressure loss rate threshold, method 600 may proceed to 660. At 660, method 600 may include indicating the absence of unwanted fuel tank emissions. In the event that the absence of unwanted fuel tank emissions is indicated, method 600 may include maintaining current vehicle operating parameters. Proceeding to 655, method 600 may include releasing fuel tank vacuum by commanding the FTIV to open, and then resealing the fuel tank by commanding the FTIV to close. While the above method includes releasing fuel tank vacuum at 655, in some examples, fuel tank vacuum may not be released, and in such examples, the FTIV may remain closed in response to the indication of the presence or absence of unwanted evaporative emissions. Method 600 may then end.

[0105] Now go to Figure 7 , shows an example graphical representation of a diurnal cycle 700 of solar intensity and temperature as a function of time of day. Incoming solar radiation 702 begins to increase at sunrise 704 and rises to a maximum near midday before sunset 706. Thus, sunrise 704 marks the time of day when the heat gain cycle is at its maximum, and sunset 706 marks the time of day when the heat loss cycle is at its maximum. Accordingly, ambient temperature 708 is shown, showing an increase in temperature from a minimum temperature 710 near sunrise 704 and a decrease in temperature from a maximum temperature 712 near sunset 706.

[0106] As will be discussed in detail below, in order to diagnose whether a structural support in a vehicle fuel tank of a diagnosed vehicle has degraded, the pressure in the fuel tank of the diagnosed vehicle (VD) may be compared to crowdsourced fuel tank pressure data from one or more vehicles or multiple vehicles located within a predetermined distance of the VD. The pressure in the fuel tank of the VD and the pressure in the fuel tank of one or more vehicles including the crowdsourced fuel tank pressure data may be retrieved or indicated at or near one of a minimum temperature 710 and / or a maximum temperature 712 when the VD is in a key-off state, and the vehicle in which the crowdsourced fuel tank pressure data is included is also in a key-off state. Additionally, data related to the fuel levels in the fuel tanks of the VD and the vehicles comprising the vehicle group may be indicated or retrieved at or near the minimum temperature 710 and / or the maximum temperature 712. As will be discussed below with reference to Figures 8 and 9As discussed in further detail, crowdsourced data including one or more of fuel tank pressure and / or fuel level can be compared to one or more of the fuel tank pressure and / or fuel level in the VD. If the crowdsourced data correlates with the data retrieved from the VD, it can be determined that the structural mounts in the VD are functioning as expected and are not degraded. However, if one or more of the fuel tank pressure data and / or fuel level data from the VD does not correlate with the fuel tank pressure data and / or fuel level data retrieved from the fleet, it can indicate that the structural mounts in the VD are degraded or are not functioning as expected.

[0107] It will be appreciated that in some examples, indicating or retrieving information or data related to the fuel tank pressure and / or fuel level in the fuel tanks of a fleet of vehicles and a VD at the highest and / or lowest temperatures may include indicating or retrieving data within a time period proximate to the highest or lowest temperatures. For example, it may be desirable to obtain one or more fuel tank pressure measurements from each individual vehicle in the fleet within a predetermined time period proximate to the highest or lowest temperature of the daily cycle. Similarly, it may be desirable to obtain one or more fuel level measurements from each individual vehicle in the fleet within a predetermined time period proximate to the highest or lowest temperature of the daily cycle. In some examples, the predetermined time period for retrieving fuel tank pressure data may constitute the same predetermined time period used for retrieving fuel level data, but in other examples, these predetermined time periods may differ. For example, the predetermined time period may include 30 minutes, 1 hour, 2 hours, 3 hours, etc. As an example, if the maximum temperature occurs at 5:00 PM and the predetermined time period includes 1 hour, pressure data may be retrieved starting at 4:30 PM and may continue until 5:30 PM. A similar procedure may be followed with respect to retrieving fuel level data. In such an example, it will be appreciated that fuel tank pressure data and fuel level data can be retrieved for both the fleet and the VD during a predetermined time period. Furthermore, as discussed, data related to fuel level can be retrieved at a predetermined time that differs from the time during which fuel tank pressure data is retrieved from the VD and fleet.

[0108] In some examples, fuel level data may be retrieved for a longer period of time near the maximum or minimum temperature than fuel tank pressure data. As an example, if the maximum temperature is indicated to occur at 5:00 PM, the predetermined time period for retrieving fuel tank pressure data may include 1 hour, while the predetermined time period for retrieving fuel level data may include 2 hours. In such an example, fuel tank pressure data may be retrieved from the time period of 4:30 PM to 5:30 PM, while fuel level data may be retrieved from the time period of 4 PM to 6 PM. Such examples are illustrative.

[0109] In the example of retrieving fuel tank pressure data and / or fuel level data from the VD and the fleet within a predetermined time period, it will be appreciated that such data can be retrieved periodically. For example, data can be retrieved at intervals of 5 minutes, 10 minutes, 20 minutes, 30 minutes, and so on. As an example, fuel tank pressure data can be recorded every 5 minutes for each vehicle in the fleet and for the VD over a period of one hour. Similarly, fuel level data can be recorded every 5 minutes for each vehicle in the fleet and for the VD over a period of one hour. In such an example, the data from each vehicle in the fleet can be averaged to obtain an average measurement value for each data set in the fleet. The average measurement values from each vehicle in the fleet can then be averaged to obtain an average fleet fuel tank pressure and / or average fleet fuel level. Similarly, an average VD fuel tank pressure and / or average VD fuel level can be obtained from the VD. In this way, the average vehicle group fuel tank pressure and / or the average vehicle group fuel level can be compared with the average VD fuel tank pressure and / or the average VD fuel level, respectively, to determine whether the fuel tank pressure data is correlated between the VD and the vehicle group, and / or whether the fuel level data is correlated between the VD and the vehicle group.

[0110] Now go to Figure 8 , a high-level example method 800 for accessing a fuel tank diagnostic is shown. More specifically, method 800 may be used to evaluate whether conditions for performing a fuel tank diagnostic are met. If so, weather forecast data may be retrieved via the vehicle controller, and the fuel tank diagnostic may be scheduled for a time period that includes the highest or lowest temperatures of the diurnal cycle. Based on the scheduling of the diagnostic, the vehicle controller may be awakened at the scheduled time to perform the diagnostic.

[0111] Although the method 800 will be described herein and with reference to Figures 1 to 3 The method 800 is described with reference to the system shown in FIG. 1 , but it should be understood that similar methods can be applied to other systems without departing from the scope of the present disclosure. The method 800 can be executed by a controller such as Figure 2 The controller 212 in FIG. 1 and may be stored as executable instructions in a non-transitory memory at the controller. The instructions for executing method 800 and the remaining methods included herein may be executed by the controller based on the instructions stored on the controller's memory and in conjunction with signals received from sensors of the vehicle system, such as those described above with reference to FIG. Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emissions system actuators, such as a fuel tank isolation valve (FTIV) (eg, 252 ), according to the methods described below.

[0112] Method 800 begins at 805 and may include evaluating current vehicle operating conditions. Operating conditions may be estimated, measured, and / or inferred and may include environmental conditions (such as temperature, humidity, barometric pressure, etc.), engine conditions (such as engine operating status, engine speed, engine load, etc.), and fuel system conditions (such as fuel level, fuel tank pressure, fuel vapor canister load status, etc.). Continuing at 810, method 800 may include indicating whether conditions are met for performing a VD (vehicle being diagnosed) fuel tank diagnostic, wherein the fuel tank diagnostic includes using V2X or V2I2V technology to determine whether the VD has a degraded fuel tank, as described above with respect to Figure 3 and Figure 7 The conditions for performing VD may include indicating that the fuel tank of the VD has no undesirable evaporative emissions. Figures 4 to 6 Any of the methods described in can be used to determine whether a fuel tank is free of undesirable evaporative emissions.

[0113] The conditions satisfied for performing the diagnosis may further include a threshold duration that has elapsed since a previous fuel tank test diagnosis. The threshold duration may include 1 day, greater than 1 day but less than 5 days, greater than 5 days but less than 10 days, greater than 10 days but less than 20 days, greater than 20 days but less than 30 days, greater than 30 days but less than 60 days, greater than 60 days but less than 100 days, etc.

[0114] For example, the conditions met at 810 may further include a key-off state.

[0115] If at 810, it is indicated that the conditions for performing a fuel tank diagnostic are not met, method 800 can proceed to 815 and can include maintaining the current vehicle operating conditions. For example, if the vehicle is running, the vehicle can be maintained in operation. In some examples, maintaining vehicle operation can include maintaining fuel to the engine to propel the vehicle. In other examples, maintaining vehicle operation can include maintaining the vehicle being propelled through a pure electric operating mode. In other examples, maintaining operation can include maintaining hybrid operation, in which the vehicle is propelled through some degree of contribution from the engine and some degree of contribution from an on-board energy storage device (e.g., a battery). In other examples, if the vehicle is in a key-off state, but the conditions for performing a fuel tank diagnostic are still not met, maintaining the current vehicle operating parameters can include maintaining the vehicle in a key-off state. Such examples are illustrative. Method 800 can then end.

[0116] Returning to 810 , in response to conditions being met for performing a fuel tank diagnostic, method 800 may proceed to 820 . At 820 , method 800 may include commanding closure of the vehicle's FTIV (e.g., 252 ). By commanding closure of the FTIV, the fuel tank may be sealed from the atmosphere and the vehicle's evaporative emissions system.

[0117] Proceeding to 825, method 800 may include obtaining predicted weather data. For example, the control system 214 (e.g., 190) may be configured to receive information via the Internet or other communication network to obtain weather information near the VD, wherein the VD vicinity may include weather information within a predetermined distance (in all directions) of the VD. Such weather information may be retrieved from one or more data servers, including government and / or private data collection services that provide predicted weather data in a retrievable format. In some examples, the weather information may be based on the vehicle location determined by an onboard GPS. The retrieved weather data may include predicted temperature, humidity, atmospheric pressure, precipitation, wind, etc. It will be appreciated that such retrieved predicted weather information may be transmitted to a vehicle controller, where the data may be processed by the controller. In one example, the retrieved weather information or data may include predicted weather information for the next 24 hours. In other examples, predicted weather information for a shorter or longer period of time may be retrieved.

[0118] With the weather forecast information retrieved by the VD controller, method 800 may proceed to 830. At 830, method 800 may include indicating whether the predicted weather data indicates a threshold temperature change of a predetermined duration, where the predetermined duration may include, for example, 24 hours. In one example, the threshold temperature change may include 15°C. However, in some examples, the threshold temperature change may include greater than 15°C, and in other examples, may include less than 15°C. It will be appreciated that the predetermined duration may include, for example, a duration during which an expected pressure change may occur in the VD, and in some examples may vary based on ambient weather conditions, the fuel level in the VD's fuel tank, the fuel composition, and the like.

[0119] If, at 830, the predicted weather information indicates that the temperature change is less than the threshold temperature change, method 800 may proceed to 835. At 835, method 800 may include scheduling a subsequent test for fuel tank diagnostics, which will be performed if the conditions for performing the diagnostics are met and the predicted weather conditions indicate that the threshold temperature change is predicted. At 835, method 800 may further include maintaining the current vehicle operating conditions, as discussed above with respect to step 815 of method 800. Method 800 may then end.

[0120] Returning to 830 , in response to the predicted threshold temperature change, method 800 may proceed to 840 . At 840 , method 800 may include obtaining weather information associated with the times of the predicted maximum and minimum temperatures for the diurnal cycle. For example, the predicted weather information may indicate a maximum temperature of 4:30 PM, while a minimum temperature of 5:30 AM may be predicted. This example is illustrative. As described above, and discussed further below, fleet data associated with fuel tank pressure and / or fuel level may be retrieved from a plurality of vehicles of similar make / model to the VD at times near and including the maximum and / or minimum temperatures of the diurnal cycle, thereby determining whether the VD fuel tank is degraded.

[0121] Therefore, proceeding to 845, method 800 may include scheduling the controller to wake up at a determined time based on the predicted maximum / minimum temperature determined at 840 of method 800. Figure 7 As discussed in , in some examples, the controller may be scheduled to be awakened at a determined time at or near the maximum and / or minimum temperature. As discussed, in some examples, it may be desirable to obtain one or more measurements related to fuel tank pressure in the VD and from the fleet, as discussed above, and this will be discussed further below. Thus, multiple measurements may be retrieved over a predetermined time period that includes the maximum and / or minimum temperature. As an example, if the predetermined time period includes 1 hour, and the maximum temperature is indicated to occur at 5 PM, then the controller may be awakened at 4:30 PM. In such an example, the fuel tank pressure and fuel level from the VD and the fleet may be retrieved during the predetermined time period, as discussed above in Figure 7 However, in some cases, it may be desirable to obtain fuel level measurements for a longer or shorter period than the fuel tank pressure measurements. In such examples, the determined time to wake the controller can be varied based on the longer predetermined period. For example, if two hours of fuel level measurements are desired and the peak temperature is predicted to be at 5 p.m., and one hour of fuel tank pressure measurements is desired, the controller can be woken at 4 p.m. so that two hours of fuel level measurements can be obtained from 4 p.m. to 6 p.m., including the predicted peak temperature. In response to scheduling the controller to wake up at the determined time, method 800 can include placing the controller into hibernation.

[0122] Proceeding to 850, it may be determined whether a determined time to wake up the controller is indicated. If a determined time is not indicated, method 800 may include maintaining the current vehicle operating conditions, which in this case may include maintaining the vehicle controller in a sleep operating mode until the determined time is indicated.

[0123] In response to the determined time indicated at 850, method 800 may proceed to 860. At 860, method 800 may include waking up the controller. In the event that the controller is awake, method 800 may proceed to 865 and may include Figure 9 Fuel tank diagnostics are performed. Method 800 may then end.

[0124] Now go to Figure 9 , shows a high-level example method 900 for performing fuel tank diagnostics. More specifically, the method 900 can be used to retrieve one or more data sets related to fuel tank pressure and fuel level in one or more vehicles or a group of vehicles so that the data can be compared with equivalent data obtained from a diagnosed vehicle (VD). Based on whether the data obtained from the VD correlates with the data obtained from the group of vehicles, it can be determined whether the VD fuel tank is degraded. As discussed, the method 900 can be used to retrieve one or more data sets related to fuel tank pressure and fuel level in one or more vehicles or a group of vehicles so that the data can be compared with equivalent data obtained from a diagnosed vehicle (VD). Based on whether the data obtained from the VD correlates with the data obtained from the group of vehicles, it can be determined whether the VD fuel tank is degraded. Figure 8 The illustrated method 800 continues.

[0125] Although the method 900 will be described herein with reference to Figures 1 to 3 The method 900 is described with reference to the system shown in FIG. 1 , but it should be understood that similar methods can be applied to other systems without departing from the scope of the present disclosure. The method 900 can be executed by a controller such as Figure 2 The controller 212 in the embodiment of the present invention may be stored as executable instructions in a non-transitory memory at the controller. The instructions for executing method 900 and the remaining methods included herein may be executed by the controller based on the instructions stored on the memory of the controller and in combination with signals received from sensors of the vehicle system, such as the sensors described above. Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emission system actuators, such as a canister ventilation valve (CVV) (e.g., 297 ), a canister purge valve (CPV) (e.g., 261 ), a fuel tank isolation valve (FTIV) (e.g., 252 ), etc., according to the methods described below.

[0126] Method 900 begins at 905 and may include generating the vehicle group or the selected vehicle group. In some examples, the vehicle group may be referred to as a plurality of vehicles, a fleet of vehicles, a group of vehicles, etc. To generate or select a vehicle group from which the VD may retrieve fuel tank pressure data and / or fuel level data, the following process executed by the VD controller may be employed. For example, the VD may send a wireless request to one or more vehicles within wireless communication or within a predetermined threshold distance or radius (e.g., 320) of the VD. The wireless request may include a request for information from the vehicle, including data related to time since last key-off, engine run time for the most recent drive cycle prior to the key-off event, fuel level, vehicle make / model information, whether the vehicle has a sealed fuel tank, fuel tank pressure data, etc. Among the vehicles receiving the wireless request, it may be further determined which of these vehicles are to be retrieved with respect to one or more data sets related to fuel tank pressure and fuel level. It will be appreciated that the vehicles determined to be retrieved with respect to the one or more data sets may constitute a vehicle group, a selected vehicle group, a plurality of vehicles, a fleet, a group of vehicles, etc. A vehicle group can be selected based on vehicle make / model, for example, only vehicles of a similar make / model to the diagnosed vehicle are considered for selection. For example, if the VD is a small sedan, then a large truck may be excluded from the vehicle group. In addition to events such as refueling, performing diagnostic tests, etc., a vehicle group can also or alternatively be selected based on whether the vehicle has a normally sealed fuel tank. For example, a vehicle that does not include a sealed fuel tank may be excluded from the vehicle group. A vehicle group can also or alternatively be selected based on whether the vehicle has a fuel level within a predetermined fuel level range. As an example, a vehicle group can be selected based on whether the vehicle's fuel level is within a threshold fuel level of the fuel level indicated for the VD. Vehicles whose fuel level is not within the threshold fuel level of the fuel level indicated for the VD may be excluded from the vehicle group. A vehicle group can also or alternatively be selected based on the time since key-off (e.g., the time since key-off is greater than a threshold key-off duration). The threshold key-off duration may include a duration during which any exhaust heat from the engine from a previous drive cycle no longer causes the generation of fuel vapor in the fuel tank or no longer affects the fuel tank temperature. For example, a vehicle that has not yet completed the threshold key-off duration may be excluded from the vehicle group.

[0127] In the event that the vehicles constituting the group have been selected by the VD controller processing the wireless request, the method 900 may proceed to 910. At 910, the method 900 may include retrieving one or more data sets including fuel tank pressure and / or one or more data sets including fuel level from the vehicles constituting the group. Retrieving one or more data sets including fuel tank pressure and / or one or more data sets including fuel level may be performed via wireless communication between the VD controller and one or more controllers of the vehicles constituting the group. As described above with respect to Figure 3 and Figure 7 As discussed, in some examples, data including fuel tank pressure and / or fuel level data may be retrieved within a predetermined time period.

[0128] In response to retrieving fuel tank pressure and / or fuel level data from the vehicles comprising the group, method 900 may proceed to 915. At 915, method 900 may include processing the data retrieved from the group. As described above, in some examples, the data including fuel tank pressure may be processed to determine average fuel tank pressure data for each vehicle, and may be further processed to determine an average total fuel tank pressure from all vehicles comprising the group within a predetermined time period for which the data was retrieved. Similarly, an average fuel tank pressure may be determined for the VD.

[0129] Regarding the fuel level data retrieved from the fleet, one or more data sets including fuel level data can be processed to determine the fluctuation of the fuel level for each vehicle over a predetermined time period. The fluctuation of the fuel level for each vehicle can then be averaged to obtain an average total fuel level fluctuation for the fleet. Similarly, the fuel level fluctuation can be determined for the VD. It will be appreciated that the controller of the VD can process the data as discussed above.

[0130] After the data retrieved from the fleet has been processed and the data from the VD has been determined, at 915, method 900 may further include the VD controller comparing the processed fuel tank pressure data from the VD with the processed fuel tank pressure data from the fleet. Additionally or alternatively, at 915, method 900 may include the VD controller comparing the processed fuel level data from the VD with the processed fuel level data from the fleet.

[0131] Proceeding to 920, method 900 may include indicating whether the retrieved data correlates with data obtained from the VD. As described above, correlation of the fuel tank pressure data from the VD with the fuel tank pressure data from the fleet may include the fuel tank pressure data from the VD being within a threshold of the fuel tank pressure data from the fleet (e.g., within 5% or less). Similarly, correlation of the fuel level data from the VD with the fuel level data from the fleet may include fluctuations in the fuel level data from the VD being within a threshold of fluctuations in the fuel level data from the fleet (e.g., within 5% or less).

[0132] If, at 920 , the data is indicated to be correlated, method 900 may proceed to 930 and may include indicating that there is no fuel tank degradation, which may include an indication that a structural mount in the fuel tank is not degraded.

[0133] In response to the absence of an indication of fuel tank degradation, method 900 may proceed to 935 and may include updating the vehicle operating conditions. Updating the vehicle operating conditions at 935 may include recording a passing result at the VD controller (e.g., 212) that includes an indication that the VD's fuel tank is not degraded. Additionally, updating the vehicle operating conditions at 935 may include maintaining the current evaporative emissions test schedule, maintaining the current fuel vapor canister purge schedule, maintaining the current engine operating conditions (at the next key-on event), etc. Method 900 may then end.

[0134] Returning to 920, in response to an indication that the fuel tank pressure and / or fuel level data from the VD does not correlate with the data retrieved from the fleet, method 900 may proceed to 925 and may include indicating fuel tank degradation, which may include indicating possible degradation of a structural mount in the fuel tank of the VD. Such indication may include setting a flag at a controller of the VD and may further include illuminating a malfunction indicator light (MIL) on an instrument panel of the VD to alert the vehicle operator that vehicle service is required.

[0135] Proceeding to 928, method 900 may include taking mitigating action in response to the indication of degradation of the VD's fuel tank. In some examples, taking mitigating action may include commanding the opening of the FTIV (e.g., 252). By commanding the opening of the FTIV, the VD's fuel tank may be less susceptible to variations in fuel tank pressure, which may help maintain the integrity of the fuel tank. It will be appreciated that when the FTIV is commanded to open, if the CVV (e.g., 297) is not already open, the CVV may also be commanded to open. With the FTIV and CVV commanded open, the VD's fuel tank may be connected to the atmosphere, and thus, the VD's fuel tank may be maintained at or near atmospheric pressure.

[0136] Proceeding to 935 , method 900 may include updating vehicle operating conditions based on the indicated fuel tank degradation. Specifically, with the fuel tank coupled to atmosphere, fuel tank vapors may be routed to a fuel vapor canister (e.g., 222 ) where the vapors may be adsorbed. However, because a VD may include a hybrid vehicle (e.g., a PHEV) with limited engine run time, engine run time may be scheduled to increase as a result of coupling the fuel tank to the fuel vapor storage canister. More specifically, because the fuel tank is coupled to the fuel vapor storage canister and atmosphere, the fuel vapors are no longer contained within a sealed fuel tank, and therefore, while the vehicle is operating, it may be desirable to purge the canister of fuel vapors more frequently than if the fuel tank of the VD were sealed, which may be accomplished by the engine manifold vacuum that occurs when the vehicle is operating with the engine combusting fuel and air.

[0137] Thus, for example, in response to an indication of fuel tank degradation, mitigation actions may include operating the engine more frequently while the vehicle is operating so that the fuel vapor canister can be purged more often. In some examples, the fuel vapor canister load may be determined by one or more temperature sensors (e.g., 232). As discussed, when fuel vapor is adsorbed by the adsorbent in the canister, heat may be generated, which may be monitored by one or more temperature sensors located in the canister, and the temperature change may be utilized by the VD controller to indicate the load state of the fuel vapor canister. Thus, in some examples, in response to an indication that the canister is saturated or near saturation with fuel vapor, the engine may be commanded to start so that fuel vapor is purged from the canister to the engine intake system for combustion. Method 900 may then end.

[0138] As discussed above with respect to method 900, due to an increase in the amount of fuel vapor absorbed via the fuel tank in the event of an indication of fuel tank degradation (e.g., degraded structural mounts), fuel vapor canister purge operations may be increased in response to commanding the FTIV to open. Figure 10 , an example method for purging a fuel vapor storage canister of a VD is shown.

[0139] Figure 10 Thus, a high-level example method 1000 for performing a purge operation in a VD is shown. Although the method 1000 will be described herein and in Figures 1 to 3 The method 1000 is described with reference to the system shown in FIG. 1 , but it should be understood that similar methods can be applied to other systems without departing from the scope of the present disclosure. The method 1000 can be executed by a controller, such as Figure 2The controller 212 in the embodiment of the present invention may be stored as executable instructions in a non-transitory memory at the controller. The instructions for executing method 1000 and the remaining methods included herein may be executed by the controller based on the instructions stored on the memory of the controller and in combination with signals received from sensors of the vehicle system, such as the sensors described above. Figures 1 to 3 The controller may utilize fuel system actuators and evaporative emission system actuators, such as a canister ventilation valve (CVV) (e.g., 297 ), a canister purge valve (CPV) (e.g., 261 ), a fuel tank isolation valve (FTIV) (e.g., 252 ), etc., according to the methods described below.

[0140] Method 1000 begins at 1005 and includes assessing current operating conditions. Operating conditions may be estimated, measured, and / or inferred and may include one or more vehicle conditions (such as vehicle speed, vehicle location, etc.), various engine conditions (such as engine status, engine load, engine speed, air-fuel ratio, etc.), various fuel system conditions (such as fuel level, fuel type, fuel temperature, etc.), various evaporative emissions system conditions (such as fuel vapor canister load, fuel tank pressure, etc.), and various ambient conditions (such as ambient temperature, humidity, barometric pressure, etc.). Continuing at 1010, method 1000 may include indicating whether canister purge conditions are met. Canister purge conditions may be indicated as being met in response to an indication that the engine is on and intake manifold vacuum is greater than a threshold intake manifold vacuum, where the threshold relates to an amount of vacuum sufficient to draw fuel vapor from the fuel vapor canister. The conditions met at 1010 may further include an indication that the canister load is greater than a threshold (e.g., saturated or nearly saturated with fuel vapor), etc. If the canister purge conditions are not met, method 1000 may proceed to 1015 and may include maintaining the current engine, evaporative emissions system, and fuel system states. For example, if the vehicle engine is indicated to be off, the engine may remain off. In another example, if the vehicle engine is indicated to be on, the engine may be maintained running based on the current engine operating conditions. Furthermore, at 1015, maintaining the fuel system and evaporative emissions system states may include maintaining the canister purge valve (e.g., 261), the fuel tank isolation valve (e.g., 252), and the canister vent valve (e.g., 297) in their current configurations. Method 1000 may then end.

[0141] Returning to 1010, if the canister purge conditions are indicated to be met, method 1000 may proceed to 1020. At 1020, method 1000 may include commanding the canister vent valve (e.g., 297) to be opened or maintained open. At 1020, method 1000 may further include maintaining the FTIV open if the FTIV is open due to an indication of fuel tank degradation, such as with respect to Figure 9However, in other examples where fuel tank degradation is indicated, closing of the FTIV may be commanded in response to purge conditions being met to preclude the fuel tank (which may be degraded) from being exposed to vacuum from the intake manifold during the purge operation.

[0142] With the canister vent valve open (and the FTIV open or closed), method 1000 may proceed to 1025 and may include periodically operating the CPV. As described above, vacuum generated by the intake manifold of the operating engine may therefore draw fresh air through the fuel vapor canister (e.g., 222) to purge stored fuel vapors to the engine for combustion. During the purge process, the amount of fuel vapor stored in the canister may be determined using the learned vapor concentration. In some examples, the duty cycle of the first canister purge valve may be adjusted in response to engine operating conditions (e.g., the vacuum level in the intake manifold) and may be further adjusted based on canister load.

[0143] Proceeding to 1030 , method 1000 may include indicating whether the fuel vapor canister loading is below a predetermined threshold canister loading. In one example, the canister loading may be indicated by a temperature change in the fuel vapor canister, as monitored by one or more temperature sensors located in the canister. In some examples, the predetermined threshold canister loading may be a canister loading indicating that the canister has little to no stored fuel vapor. For example, the predetermined threshold canister loading may include a canister loading of 25%, 20%, 15%, 10%, or less.

[0144] Thus, at 1030, if the indicated canister load is not less than a predetermined threshold canister load, method 1000 may return to 1025 and may include continuing to periodically operate the CPV until the indicated canister load has reached a predetermined threshold canister load. Alternatively, at 1030, if the indicated canister load has reached a predetermined threshold canister load, method 1000 may proceed to 1035. At 1035, method 1000 may include commanding the CPV to close. By commanding the CPV to close, the evaporative emissions system (and the fuel system, if the FTIV remains open) may be decoupled from the engine intake system. In response to commanding the CPV to close, if the FTIV was commanded closed during the purge period, and if the fuel tank has previously been indicated to be degraded (e.g., structural support degradation), as described with respect to Figures 8 and 9 As discussed, the FTIV may then be commanded open again to couple the fuel tank to atmosphere via the open CVV.

[0145] Proceeding to 1045 , method 1000 may include updating the canister load status and updating the canister purge schedule. For example, the canister load status may be updated to reflect the most recent purge event. Updating the canister purge schedule at 1045 may include scheduling a further canister purge event in response to the canister load status indicated after the most recent purge event. Method 1000 may then end.

[0146] Now go to Figure 11 , shows an example timeline 1100 for performing a fuel tank test diagnostic. More specifically, timeline 1100 shows the example timeline 1100 for performing the above-mentioned Figure 3 、 Figure 7 and Figures 8 and 9Example timeline for a fuel tank diagnostic discussed herein. Timeline 1100 includes curve 1105, which indicates whether the diagnosed vehicle (VD) is running (yes) or not (no) (e.g., key on), and curve 1110, which indicates whether the conditions for the fuel tank diagnostic are met (yes) or not (no) over time. Timeline 1100 further includes curve 1115, which indicates the change in fuel tank pressure in the VD, as monitored by the VD FTPT (e.g., 291), over time. Timeline 1100 further includes curve 1120, which indicates the change in fuel level in the VD (monitored by the fuel level indicator FLI) over time. The fuel level in the fuel tank may increase (+) or decrease (-). Timeline 1100 further includes curve 1125, which indicates whether the VD FTIV is open or closed over time. Timeline 1100 further includes curve 1130, which indicates the change in ambient temperature over time. Line 1131 represents a predetermined time period for retrieving information from the vehicles comprising the fleet. Timeline 1100 further includes a curve 1135, which indicates whether (yes) or (no) the fleet data has been retrieved via the VD controller over time. Timeline 1100 further includes a curve 1140, which indicates the change or fluctuation of the average fleet fuel level over time. Fluctuation can be not applicable (n / a), no fluctuation (0), or a fluctuation greater than 0 (+). Timeline 1100 further includes a curve 1145, which indicates the change of the average fleet fuel tank pressure over time. Over time, the average fleet fuel tank pressure can be not applicable (n / a), or can be greater (e.g., increasing) (+) or less (e.g., decreasing) (-). Timeline 1100 further includes a curve 1150, which indicates whether the VD data including fuel level and / or fuel tank pressure is correlated (yes) or uncorrelated (no) with the fleet data including fuel tank pressure and / or fuel level. Timeline 1100 further includes a curve 1155 that indicates the presence (yes) or absence (no) of degradation in the VD fuel tank (e.g., degradation of a structural mount) over time. Timeline 1100 further includes a curve 1160 that indicates the change in VD fuel vapor canister loading over time. Over time, the canister loading may increase (+) or decrease (-).

[0147] At time t0, the vehicle is in operation (curve 1105), thus indicating that the conditions for performing fuel tank diagnostics (curve 1100) are not met. A significant positive pressure (relative to atmosphere) exists in the VD fuel tank (curve 1115). The VD fuel tank is more than half full (curve 1120), and the VD FTIV is in a closed configuration (curve 1125). The ambient temperature is low (curve 1130). Because the conditions for performing fuel tank diagnostics have not been indicated, no indication is given to retrieve fleet data (curve 1135), the average fleet fuel level change is not applicable (curve 1140), the average fleet fuel tank pressure is not applicable (curve 1145), and whether the VD data is correlated with fleet data is not applicable (curve 1150). No indication is given for VD fuel tank degradation (1155), where the fuel tank degradation is associated with degradation of a structural mount in the VD fuel tank. Finally, the VD fuel vapor canister load indicates that the VD canister is less than half full.

[0148] At time t1, a key-off event is indicated. Therefore, the VD controller may determine whether the conditions for performing a fuel tank diagnostic are met, as discussed above at step 810 of method 800. In response to the conditions being met at time t1, the VD fuel tank may be sealed relative to the atmosphere (curve 1125). Additionally, as discussed with respect to Figure 8 As discussed, predicted weather data can be obtained by the VD controller. Although not explicitly shown in the timeline 1100, it will be understood that at time t1, it can be further indicated whether a threshold temperature change for the next 24-hour period is predicted. In this example timeline 1100, it can be understood that the threshold temperature change is predicted, such as indicated via the VD controller in response to receiving the predicted weather information. Based on the predicted weather data, the time point of the maximum temperature of the daily cycle and the time point of the minimum temperature of the daily cycle can be determined by the VD controller. In the case of determining or indicating the maximum / minimum temperature, the VD controller can be arranged to wake up at or near the determined maximum and / or minimum temperature. After the wake-up time is arranged at time t1, the VD controller can be placed in a sleep state.

[0149] Between t1 and t2, the ambient temperature rises while the VD controller sleeps with the FTIV closed. Although the VD controller does not wake up to monitor the FTPT and fuel level, the VD's FTPT and fuel level are shown for illustrative purposes. For example, between t1 and t3, the pressure in the fuel tank remains stable or slightly decreases, which may indicate an increase in tank volume, as might occur if the structural mounts degrade. Furthermore, at t2, the fuel level decreases, which may occur if the fuel tank volume increases due to structural mount degradation.

[0150] At time t3, the vehicle controller wakes up because the scheduled wake-up time has been indicated. The vehicle controller may remain awake for a predetermined period of time while performing diagnostic tests. The predetermined period of time is illustrated by line 1131. Thus, at time t3, the VD controller may identify a group of vehicles from which to receive one or more data sets including fuel tank pressure and one or more data sets including fuel level data, and may therefore begin receiving these data sets (curve 1135). It will be appreciated that the predetermined period of time represented by line 1131 may include a duration encompassing the highest (or lowest, in other examples, lowest) temperature of the diurnal cycle. In this example, based on curve 1130, it will be appreciated that the predetermined period of time encompasses the highest temperature. Furthermore, it will be appreciated that the VD controller may retrieve fuel level data and fuel tank pressure data for the VD during the predetermined period of time.

[0151] At time t4, the fuel level in the VD decreases slightly, as indicated by curve 1120. Similarly, at time t5, the fuel level decreases slightly again. This event may indicate an expansion or increase in the volume of the VD fuel tank. Thus, the VD fuel tank pressure is indicated to have decreased slightly over a predetermined period of time, which may be a result of the increase or expansion of the VD fuel tank volume. It will be appreciated that these events related to changes or fluctuations in the VD fuel level and fuel tank pressure may be recorded by the VD controller.

[0152] Alternatively, during the predetermined time period represented by line 1131, the fuel level variation in the fleet (e.g., average fuel level fluctuation over time) is indicated as stable or having little fluctuation. Similarly, the average fleet fuel tank pressure remains stable during the predetermined time period 1131. Therefore, at time t6, when the predetermined time period for retrieving fuel level and tank pressure measurements from the fleet and VD has elapsed, it can be understood that the conditions for performing a fuel tank diagnostic (curve 1110) are no longer met. Therefore, at time t6, the data corresponding to the fuel level and tank pressure data retrieved from the VD can be compared with the fuel level and tank pressure data retrieved from the fleet. At time t6, the VD data is indicated as uncorrelated with the fleet data (curve 1150) because the VD data, including the fuel level, is indicated as fluctuating (see curve 1120), and the tank pressure data is unstable and less than the average fleet fuel tank pressure data. Thus, at time t6, degradation of the VD fuel tank is indicated, which may include an indication of degradation of a VD fuel tank structural mount. With the indication of degradation of the VD structural mount, the VD's FTIV is commanded to open at time t6, thereby coupling the VD's fuel tank to atmosphere (via an open CVV (not shown in timeline 1100)). With the VD FTIV commanded to open at time t6, fuel tank vapors are routed to the fuel vapor storage canister (e.g., 222), and thus, the VD's fuel vapor storage canister load increases between times t6 and t7 (plot 1160).

[0153] In this way, it can be determined whether the structural mounts in a vehicle's fuel tank are functioning as expected or whether they have degraded. By performing such testing regularly, any issues with the integrity of the fuel tank can be identified, allowing mitigating actions to be taken to maintain the integrity of the fuel tank. For example, because a fuel tank with degraded structural mounts may be more susceptible to the development of undesirable evaporative emissions sources, such actions may result in a reduction in undesirable evaporative emissions originating from the fuel tank.

[0154] A technical effect is the recognition that, by using V2V or V2I2V communication technology, the integrity of the structural mounts located in the fuel tank of a diagnosed vehicle (VD) can be diagnosed without coupling the fuel tank to a fuel vapor storage canister, which can reduce undesirable evaporative emissions in hybrid vehicles. Another technical effect is the recognition that, in response to an indication of fuel tank degradation (e.g., structural mount degradation), the VD's fuel tank can be coupled to the fuel vapor storage canister and atmosphere to maintain the structural integrity of the fuel tank. A further technical effect is the recognition that, in response to coupling the VD's fuel tank to the fuel vapor storage canister and atmosphere, the canister purge schedule can be updated so that the canister is purged more frequently to reduce the chance of undesirable evaporative emissions due to saturation of the fuel tank fuel vapor in the fuel vapor storage canister.

[0155] References in this article Figures 1 to 3 The systems described and referenced herein Figures 4 to 6 and Figures 8 to 10The described method can implement one or more systems and one or more methods. In one example, a method includes: sealing a fuel tank of a diagnosed vehicle; retrieving fuel tank pressure-related data from a group of related vehicles; and, in response to the fuel tank pressure-related data from the group of vehicles not being sufficiently correlated with a set of fuel tank pressure-related data from the diagnosed vehicle, indicating degradation of the fuel tank of the diagnosed vehicle. In a first example of the method, the method may include wherein retrieving the fuel tank pressure-related data from the group of vehicles includes wirelessly retrieving data from the group of vehicles via a controller of the diagnosed vehicle. A second example of the method optionally includes the first example and further includes, before retrieving the fuel tank pressure-related data from the group of vehicles, testing to determine whether there is undesirable evaporative emissions originating from the fuel tank of the diagnosed vehicle, and, in response to an indication of the absence of undesirable evaporative emissions originating from the fuel tank of the diagnosed vehicle, retrieving the fuel tank pressure-related data from the group of vehicles, wherein retrieving the fuel tank pressure-related data from the group of vehicles further includes a key-off status of the diagnosed vehicle. A third example of the method optionally includes any one or more or each of the first to second examples, and further includes wherein the vehicle group includes vehicles of a similar make / model to the diagnosed vehicle, vehicles with sealed fuel tanks, vehicles with fuel levels within a predetermined fuel level range, vehicles that have not been operated for a threshold key-off duration, and / or vehicles within a predetermined distance of the diagnosed vehicle. A fourth example of the method optionally includes any one or more or each of the first to third examples, and further includes wherein the predetermined fuel level range includes fuel levels within a threshold fuel level of the fuel level indicated for the diagnosed vehicle. A fifth example of the method optionally includes any one or more or each of the first to fourth examples, and further includes wherein the fuel tank pressure-related data from the vehicle group includes one or more datasets including fuel tank pressure data and one or more datasets including fuel level data from the fuel tanks of the vehicles comprising the vehicle group; and wherein the fuel tank pressure-related datasets from the diagnosed vehicle include a fuel level dataset from the diagnosed vehicle and a fuel tank pressure dataset from the diagnosed vehicle. A sixth example of the method optionally includes any one or more or each of the first to fifth examples, and further includes where the fuel tank pressure related data from the vehicle group is not sufficiently correlated with the fuel tank pressure related data set from the diagnosed vehicle includes an indication that the fuel tank pressure related data from the vehicle group is not within a predetermined threshold of the fuel tank pressure related data set from the diagnosed vehicle.A seventh example of the method optionally includes any one or more or each of the first through sixth examples, and further includes wherein retrieving fuel tank pressure-related data from the fleet of vehicles comprises retrieving fuel tank pressure-related data from the fleet of vehicles within a predetermined time period, the time period encompassing the highest and / or lowest temperatures of a daily cycle. An eighth example of the method optionally includes any one or more or each of the first through seventh examples, and further includes taking a mitigating action in response to an indication of degradation of the fuel tank of the diagnosed vehicle. A ninth example of the method optionally includes any one or more or each of the first through eighth examples, and further includes wherein the mitigating action comprises fluidly coupling the fuel tank to a fuel vapor storage canister located in an evaporative emissions system of the vehicle; and wherein the fuel tank and the fuel vapor storage canister are further fluidly coupled to atmosphere. A tenth example of the method optionally includes any one or more or each of the first through ninth examples, and further includes wherein indicating degradation of the fuel tank of the diagnosed vehicle comprises indicating that one or more structural supports in the fuel tank are degraded or not functioning as intended. An eleventh example of the method optionally includes any one or more or each of the first through tenth examples, and further includes wherein the fuel tank is plastic; and wherein the vehicle comprises a hybrid vehicle.

[0156] Another example of a method includes, in response to conditions being met for performing a fuel tank diagnostic on a diagnosed vehicle regarding whether one or more structural supports configured to provide structural integrity to the fuel tank are functioning as intended: sealing the fuel tank of the diagnosed vehicle; transmitting a wireless request from a controller of the diagnosed vehicle to one or more vehicles; selecting, by the controller of the diagnosed vehicle, a group of vehicles from the one or more vehicles from which to retrieve information regarding fuel tank pressure; wirelessly retrieving the information regarding fuel tank pressure from the group of vehicles; also retrieving a dataset regarding fuel tank pressure from the diagnosed vehicle, and subsequently comparing the information regarding fuel tank pressure from the group of vehicles; and, in response to the information regarding fuel tank pressure from the group of vehicles not correlating with the dataset regarding fuel tank pressure from the diagnosed vehicle, indicating degradation of one or more of the one or more structural supports of the diagnosed vehicle. In the first example of the method, the method includes wherein the conditions being met for performing the fuel tank diagnostic include a key-off state of the diagnosed vehicle, a time since key-off being greater than a threshold duration, and / or an indication that undesirable evaporative emissions are absent from the fuel tank of the diagnosed vehicle. A second example of the method optionally includes the first example and further includes wherein selecting the vehicle group includes excluding from the vehicle group vehicles that are different makes / models than the diagnosed vehicle, excluding from the vehicle group vehicles that do not have sealed fuel tanks, excluding from the vehicle group vehicles that have fuel levels outside a predetermined fuel level range, and excluding from the vehicle group vehicles that have not been deactivated or shut down for a threshold key-off duration. A third example of the method optionally includes any one or more or each of the first and second examples and further includes wherein after sealing the fuel tank of the diagnosed vehicle and before sending the wireless request from the controller of the diagnosed vehicle to one or more vehicles, the controller of the diagnosed vehicle is hibernated; and the controller of the diagnosed vehicle is awakened at a predetermined time near a maximum temperature of a daily cycle or a minimum temperature of the daily cycle to select the vehicle group to retrieve information about fuel tank pressure from the vehicle group and also retrieve a data set about fuel tank pressure from the diagnosed vehicle.A fourth example of the method optionally includes any one or more or each of the first to third examples, and further includes taking mitigating action in response to an indication of one or more degradation in the one or more structural supports of the diagnosed vehicle, wherein taking mitigating action includes: unsealing the fuel tank of the diagnosed vehicle to fluidly couple the fuel tank to the atmosphere; capturing fuel vapor from the fuel tank of the diagnosed vehicle in a fuel vapor storage canister located in an evaporative emissions system of the diagnosed vehicle; and, in response to the fuel tank being fluidly coupled to the fuel vapor storage canister, updating a schedule for purging the fuel vapor storage canister so that fuel vapor is purged from the fuel vapor storage canister more frequently.

[0157] An example of a system for a hybrid vehicle includes: a fuel tank selectively fluidly coupled to a fuel vapor canister via a conduit; a fuel tank isolation valve located in the conduit between the fuel tank and the fuel vapor canister and configured to seal the fuel tank relative to the fuel vapor canister and the atmosphere when closed; a fuel tank pressure sensor (FTPT) located in a vapor recovery line between the fuel tank and the fuel tank isolation valve; a fuel level indicator located in the fuel tank of the hybrid vehicle; a wireless communication device; and a controller configured with instructions stored in a non-volatile memory that, when executed, cause the controller to: seal the fuel tank; wirelessly retrieve weather forecast data to the controller to determine a maximum temperature and a minimum temperature corresponding to a current diurnal cycle; schedule a predetermined time to wake the controller near the maximum temperature or the minimum temperature; after scheduling the time to wake the controller, put the controller to sleep; and waking up the controller to perform a fuel tank diagnosis on the fuel tank of the hybrid vehicle; performing the fuel tank diagnosis by retrieving fuel tank pressure data and fuel level data from a group of vehicles within a predetermined distance of the hybrid vehicle, retrieving a fuel tank pressure dataset and a fuel level dataset from the hybrid vehicle, and comparing the fuel tank pressure data and fuel level data from the group of vehicles with the fuel tank pressure dataset and fuel level dataset from the hybrid vehicle; indicating that the fuel tank of the hybrid vehicle is degraded in response to the fuel tank pressure data and fuel level data from the group of vehicles not correlating with the fuel tank pressure dataset and fuel level dataset, respectively; and taking mitigating action to prevent further degradation of the fuel tank of the hybrid vehicle in response to the fuel tank of the hybrid vehicle being indicated as being degraded, wherein the mitigating action comprises fluidly coupling the fuel tank of the hybrid vehicle to the fuel vapor filter canister and the atmosphere. In a first example of the system, the system further includes a temperature sensor located in the fuel vapor canister and configured to indicate a canister load state based on a temperature change within the fuel vapor canister; and wherein the controller stores further instructions to update a purge schedule of the fuel vapor canister to purge the fuel vapor canister in response to an indication that the canister load state is greater than a threshold load state.A second example of the system optionally includes the first example and further includes wherein the controller stores further instructions to indicate degradation of the fuel tank of the hybrid vehicle in response to fuel tank pressure data and fuel level data from the group of vehicles not correlating with the fuel tank pressure dataset and fuel level dataset, wherein the non-correlation includes the fuel tank pressure data from the group of vehicles differing by greater than 5% from the fuel tank pressure dataset from the hybrid vehicle and / or the fuel level data from the group of vehicles differing by greater than 5% from the fuel level dataset from the hybrid vehicle.

[0158] Note that the example control and estimation routines included herein can be used with a variety of engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-volatile memory and can be executed by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, etc. Thus, the various actions, operations, and / or functions shown may be performed in parallel in the order shown, or in some cases omitted. Similarly, the order of processing is not necessarily required to achieve the features and advantages of the exemplary embodiments described herein, but is provided for ease of illustration and description. Depending on the specific strategy used, one or more of the actions, operations, and / or functions shown may be performed repeatedly. In addition, the described actions, operations, and / or functions may graphically represent code to be programmed into the non-volatile memory of a computer-readable storage medium in an engine control system, where the described actions are implemented by executing instructions in conjunction with an electronic controller in a system including various engine hardware components.

[0159] It should be understood that the configurations and procedures disclosed herein are exemplary in nature, and that these specific embodiments should not be considered limiting, as many variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4-cylinder, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations and other features, functions, and / or properties disclosed herein.

[0160] The following claims specifically point out certain combinations and subcombinations believed to be novel and non-obvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also deemed to be included within the subject matter of the present disclosure.

[0161] According to the present invention, a method is provided, comprising: sealing a fuel tank of a diagnosed vehicle; retrieving fuel tank pressure related data from a group of related vehicles; and indicating degradation of the fuel tank of the diagnosed vehicle in response to the fuel tank pressure related data from the group of vehicles not being sufficiently correlated with a fuel tank pressure related data set from the diagnosed vehicle.

[0162] According to one embodiment, the above invention is further characterized in that retrieving the fuel tank pressure related data from the fleet of vehicles includes wirelessly retrieving data from the fleet of vehicles via a controller of the diagnosed vehicle.

[0163] According to one embodiment, the above invention is further characterized by performing a test to determine whether there is unwanted evaporative emissions originating from the fuel tank of the diagnosed vehicle before retrieving the fuel tank pressure related data from the vehicle group; and retrieving the fuel tank pressure related data from the vehicle group in response to an indication that there is no unwanted evaporative emissions originating from the fuel tank of the diagnosed vehicle, wherein the retrieving the fuel tank pressure related data from the vehicle group further includes the key-off status of the diagnosed vehicle.

[0164] According to one embodiment, the vehicle group includes vehicles of a similar make / model to the diagnosed vehicle, vehicles with sealed fuel tanks, vehicles with fuel levels within a predetermined fuel level range, vehicles that have not been operated for a threshold key-off duration, and / or vehicles within a predetermined distance of the diagnosed vehicle.

[0165] According to one embodiment, the predetermined fuel level range includes fuel levels that are within a threshold fuel level of a fuel level indicated for the diagnosed vehicle.

[0166] According to one embodiment, the fuel tank pressure related data from the vehicle group includes one or more data sets including fuel tank pressure data and one or more data sets including fuel level data from the fuel tanks of the vehicles constituting the vehicle group; and wherein the fuel tank pressure related data sets from the diagnosed vehicle include a fuel level data set from the diagnosed vehicle and a fuel tank pressure data set from the diagnosed vehicle.

[0167] According to one embodiment, the above invention is further characterized in that the fuel tank pressure related data from the group of vehicles is not sufficiently correlated with the fuel tank pressure related data set from the diagnosed vehicle includes an indication that the fuel tank pressure related data from the group of vehicles is not within a predetermined threshold of the fuel tank pressure related data set from the diagnosed vehicle.

[0168] According to one embodiment, retrieving fuel tank pressure related data from the fleet of vehicles comprises retrieving fuel tank pressure related data from the fleet of vehicles within a predetermined time period, the time period comprising a maximum and / or a minimum temperature of a diurnal cycle.

[0169] According to one embodiment, the above invention is further characterized by taking mitigating action in response to an indication of degradation of the fuel tank of the diagnosed vehicle.

[0170] According to one embodiment, the mitigating action includes fluidly coupling the fuel tank to a fuel vapor storage canister located in an evaporative emissions system of the vehicle; and wherein the fuel tank and the fuel vapor storage canister are further fluidly coupled to atmosphere.

[0171] According to one embodiment, the above invention is further characterized by indicating that the fuel tank of the diagnosed vehicle is degraded includes indicating that one or more structural supports in the fuel tank are degraded or not functioning as desired.

[0172] According to one embodiment, the above invention is further characterized by the fuel tank being plastic; and wherein the vehicle comprises a hybrid vehicle.

[0173] According to the present invention, a method is provided, comprising: in response to a condition being met while performing a fuel tank diagnosis on a diagnosed vehicle regarding whether one or more structural supports configured to provide structural integrity to the fuel tank are functioning as expected: sealing the fuel tank of the diagnosed vehicle; sending a wireless request from a controller of the diagnosed vehicle to one or more vehicles; selecting, by the controller of the diagnosed vehicle, a group of vehicles from the one or more vehicles from which to retrieve information regarding fuel tank pressure; wirelessly retrieving the information regarding fuel tank pressure from the group of vehicles; also retrieving a data set regarding fuel tank pressure from the diagnosed vehicle, and subsequently comparing the information regarding fuel tank pressure from the group of vehicles; and in response to the information regarding fuel tank pressure from the group of vehicles not correlating with the data set regarding fuel tank pressure from the diagnosed vehicle, indicating degradation of one or more of the one or more structural supports of the diagnosed vehicle.

[0174] According to one embodiment, the above invention is further characterized in that the conditions for performing the fuel tank diagnosis are met including a key-off state of the diagnosed vehicle, a time since key-off being greater than a threshold duration, and / or an indication that no undesirable evaporative emissions are present in the fuel tank of the diagnosed vehicle.

[0175] According to one embodiment, selecting the vehicle group includes excluding from the vehicle group vehicles of a different make / model than the diagnosed vehicle, excluding from the vehicle group vehicles without a sealed fuel tank, excluding from the vehicle group vehicles with a fuel level not within a predetermined fuel level range, and excluding from the vehicle group vehicles that have not been deactivated or out of service for a threshold key-off duration.

[0176] According to one embodiment, the above invention is further characterized by putting the controller of the diagnosed vehicle to sleep after sealing the fuel tank of the diagnosed vehicle and before sending the wireless request from the controller of the diagnosed vehicle to one or more vehicles; and waking up the controller of the diagnosed vehicle at a predetermined time point near the maximum temperature of a daily cycle or the minimum temperature of the daily cycle to select the group of vehicles to retrieve information about the fuel tank pressure from the group of vehicles and also retrieve a data set about the fuel tank pressure from the diagnosed vehicle.

[0177] According to one embodiment, the above invention is further characterized by taking mitigating action in response to an indication of one or more degradation in the one or more structural mounts of the diagnosed vehicle, wherein taking mitigating action includes: unsealing the fuel tank of the diagnosed vehicle to fluidly couple the fuel tank to atmosphere; capturing fuel vapor from the fuel tank of the diagnosed vehicle in a fuel vapor storage canister located in an evaporative emissions system of the diagnosed vehicle; and, in response to the fuel tank being fluidly coupled to the fuel vapor storage canister, updating a schedule for purging the fuel vapor storage canister to more frequently purge fuel vapor from the fuel vapor storage canister.

[0178] According to the present invention, a system for a hybrid vehicle is provided, comprising: a fuel tank selectively fluidically coupled to a fuel vapor canister via a conduit; a fuel tank isolation valve located in the conduit between the fuel tank and the fuel vapor canister and configured to seal the fuel tank relative to the fuel vapor canister and the atmosphere when closed; a fuel tank pressure sensor (FTPT) located in a vapor recovery line between the fuel tank and the fuel tank isolation valve; a fuel level indicator located in the fuel tank of the hybrid vehicle; a wireless communication device; and a controller configured with instructions stored in a non-volatile memory that, when executed, cause the controller to: seal the fuel tank; wirelessly acquire weather forecast data to the controller to determine a maximum temperature and a minimum temperature corresponding to a current diurnal cycle; schedule a predetermined time to wake the controller when approaching the maximum temperature or the minimum temperature; put the controller to sleep after scheduling the time to wake the controller; and and waking up the controller at the predetermined time to perform a fuel tank diagnosis on the fuel tank of the hybrid vehicle; performing the fuel tank diagnosis by retrieving fuel tank pressure data and fuel level data from a group of vehicles within a predetermined distance of the hybrid vehicle, retrieving a fuel tank pressure dataset and a fuel level dataset from the hybrid vehicle, and comparing the fuel tank pressure data and fuel level data from the group of vehicles with the fuel tank pressure dataset and fuel level dataset from the hybrid vehicle; indicating that the fuel tank of the hybrid vehicle is degraded in response to the fuel tank pressure data and fuel level data from the group of vehicles not being correlated with the fuel tank pressure dataset and fuel level dataset, respectively; and taking mitigating action to prevent further degradation of the fuel tank of the hybrid vehicle in response to the fuel tank of the hybrid vehicle being indicated as being degraded, wherein the mitigating action comprises fluidly coupling the fuel tank of the hybrid vehicle to the fuel vapor filter canister and the atmosphere.

[0179] According to one embodiment, the above invention is further characterized by a temperature sensor located in the fuel vapor canister and configured to indicate a canister load state based on a temperature change within the fuel vapor canister; and wherein the controller stores further instructions to update a purge schedule of the fuel vapor canister to purge the fuel vapor canister in response to an indication that the canister load state is greater than a threshold load state.

[0180] According to one embodiment, the controller stores further instructions to indicate degradation of the fuel tank of the hybrid vehicle in response to fuel tank pressure data and fuel level data from the group of vehicles not correlating with the fuel tank pressure dataset and fuel level dataset, wherein the non-correlation includes the fuel tank pressure data from the group of vehicles differing by more than 5% from the fuel tank pressure dataset from the hybrid vehicle, and / or the fuel level data from the group of vehicles differing by more than 5% from the fuel level dataset from the hybrid vehicle.

Claims

1. A method for a vehicle, comprising: In response to a condition being met for performing a fuel tank diagnostic on the diagnosed vehicle regarding whether one or more structural supports configured to provide structural integrity to the fuel tank are functioning as expected: Seal the fuel tank of the vehicle being diagnosed; Retrieving fuel tank pressure related data from a group of related vehicles; as well as In response to the fuel tank pressure related data from the fleet not being sufficiently correlated with the fuel tank pressure related data set from the diagnosed vehicle, indicating degradation of one or more of the one or more structural mounts of the diagnosed vehicle without coupling the fuel tank to a fuel vapor storage canister and without coupling the fuel tank to atmosphere. 2 . The method of claim 1 , wherein retrieving fuel tank pressure related data from the fleet of vehicles comprises wirelessly retrieving data from the fleet of vehicles via a controller of the diagnosed vehicle.

3. The method of claim 1, further comprising: Prior to retrieving fuel tank pressure related data from the fleet of vehicles, performing a test to determine if there are undesirable evaporative emissions originating from the fuel tank of the diagnosed vehicle; as well as Responsive to an indication of an absence of unwanted evaporative emissions originating from the fuel tank of the diagnosed vehicle, retrieving fuel tank pressure related data from the fleet of vehicles, wherein retrieving fuel tank pressure related data from the fleet of vehicles further includes a key-off state of the diagnosed vehicle.

4. The method of claim 1 , wherein the vehicle group includes vehicles having a similar make / model to the diagnosed vehicle, vehicles having sealed fuel tanks, vehicles having fuel levels within a predetermined fuel level range, vehicles that have not been operated for a threshold key-off duration, and / or vehicles within a predetermined distance of the diagnosed vehicle. 5 . The method of claim 4 , wherein the predetermined fuel level range includes fuel levels that are within a threshold fuel level of a fuel level indicated for the diagnosed vehicle.

6. The method of claim 1 , wherein the fuel tank pressure related data from the fleet includes one or more data sets including fuel tank pressure data and one or more data sets including fuel level data from fuel tanks of vehicles comprising the fleet; and in, The fuel tank pressure related data set from the diagnosed vehicle includes a fuel level data set from the diagnosed vehicle and a fuel tank pressure data set from the diagnosed vehicle.

7. The method of claim 1 , wherein the fuel tank pressure related data from the group of vehicles is not sufficiently correlated with the fuel tank pressure related data set from the diagnosed vehicle comprises an indication that the fuel tank pressure related data from the group of vehicles is not within a predetermined threshold of the fuel tank pressure related data set from the diagnosed vehicle.

8. The method of claim 1, wherein retrieving fuel tank pressure related data from the fleet of vehicles comprises retrieving fuel tank pressure related data from the fleet of vehicles within a predetermined time period, the time period encompassing a maximum and / or minimum temperature of a diurnal cycle.

9. The method of claim 1, further comprising: Mitigating action is taken in response to the indication of degradation of the fuel tank of the diagnosed vehicle.

10. The method of claim 9, wherein the mitigating action comprises fluidly coupling the fuel tank to a fuel vapor storage canister located in an evaporative emissions system of the vehicle; and Wherein the fuel tank and the fuel vapor storage canister are further fluidly coupled to atmosphere. 11 . The method of claim 1 , wherein indicating that the fuel tank of the diagnosed vehicle is degraded comprises indicating that one or more structural supports in the fuel tank are degraded or not functioning as expected.

12. The method of claim 1, wherein the fuel tank is plastic; and The vehicle comprises a hybrid vehicle.

13. A system for a hybrid vehicle, comprising: a fuel tank selectively fluidly coupled to a fuel vapor canister via a conduit; a fuel tank isolation valve positioned within the conduit between the fuel tank and the fuel vapor canister and configured to seal the fuel tank from the fuel vapor canister and the atmosphere when closed; a fuel tank pressure sensor (FTPT) located in the vapor recovery line between the fuel tank and the fuel tank isolation valve; a fuel level indicator located in the fuel tank of the hybrid vehicle; wireless communication devices; and A controller configured with instructions stored in a non-transitory memory, the instructions when executed causing the controller to: sealing the fuel tank; wirelessly acquiring weather forecast data to the controller to determine the maximum and minimum temperatures corresponding to the current diurnal cycle; scheduling a predetermined time to wake up the controller when approaching the maximum temperature or the minimum temperature; After arranging the time for waking up the controller, putting the controller into sleep mode; waking up the controller at the predetermined time to perform a fuel tank diagnosis on the fuel tank of the hybrid vehicle; performing the fuel tank diagnostics by retrieving fuel tank pressure data and fuel level data from a group of vehicles within a predetermined distance of the hybrid vehicle, retrieving a fuel tank pressure dataset and a fuel level dataset from the hybrid vehicle, and comparing the fuel tank pressure data and fuel level data from the group of vehicles with the fuel tank pressure dataset and the fuel level dataset from the hybrid vehicle; In response to fuel tank pressure data and fuel level data from the fleet not correlating with the fuel tank pressure dataset and the fuel level dataset, respectively, indicating degradation of the fuel tank of the hybrid vehicle; and In response to the fuel tank of the hybrid vehicle being indicated as degraded, taking mitigating action to prevent further degradation of the fuel tank of the hybrid vehicle, wherein the mitigating action includes fluidly coupling the fuel tank of the hybrid vehicle to the fuel vapor canister and atmosphere.

14. The system of claim 13, further comprising a temperature sensor located in the fuel vapor canister and configured to indicate a canister load state based on a temperature change within the fuel vapor canister; and Wherein the controller stores further instructions to update a purge schedule of the fuel vapor canister to purge the fuel vapor canister in response to an indication that the canister load state is greater than a threshold load state.

15. The system of claim 13 , wherein the controller stores further instructions to indicate degradation of the fuel tank of the hybrid vehicle in response to fuel tank pressure data and fuel level data from the fleet being uncorrelated with the fuel tank pressure dataset and the fuel level dataset, wherein the uncorrelation comprises the fuel tank pressure data from the fleet differing by greater than 5% from the fuel tank pressure dataset from the hybrid vehicle and / or the fuel level data from the fleet being uncorrelated with the fuel level dataset from the hybrid vehicle.

Images