Method and system for evaporative emission system

Abstract

The present disclosure provides methods and systems for an evaporative emission system. Methods and systems are provided for a fuel system. In one example, a method may include adjusting operation of a fuel operated heater (FOH) in response to a condition of a canister. The FOH is activated and configured to flow heated air to the canister to facilitate desorption of fuel vapors stored therein.

Description

Technical Field

[0001] The present description generally relates to methods and systems for evaporative emission control systems for vehicles. Background Art

[0002] Vehicle fuel systems include an evaporative emissions control system (EVAP) that is designed to reduce the release of fuel vapors to the atmosphere. For example, vaporized hydrocarbons (HC) from the fuel tank may be stored in a fuel vapor canister filled with an adsorbent that adsorbs and stores the vapors. At a later time, such as when the engine is in operation, the evaporative emissions control system allows the vapors to be drawn into the engine intake manifold for use as fuel. Fuel vapors may be generated as refueling vapors, running loss vapors, heat soak vapors, and daytime temperature vapors. In hybrid vehicles, the fuel vapors stored in the canister are primarily refueling vapors.

[0003] Vehicle manufacturers may increase the electrical capability of one or more vehicles in a vehicle fleet. The expansion of electric vehicle capabilities may result in a reduction in engine operating time, and therefore a reduction in the opportunity to consume fuel vapor during canister ventilation. In addition, non-hybrid vehicles (such as pure internal combustion engine (ICE) vehicles) may be equipped with start / stop and other features to reduce engine running time. Each of these advances presents challenges to the frequency with which canister cleaning may occur. Therefore, different methods and systems than those that already exist may be needed to meet various goals. Summary of the invention

[0004] In one example, the above problems can be solved by a method for heating air using a fuel operated heater (FOH) and directing the heated air from the FOH to a canister in an evaporative emission control system. By doing so, the FOH can promote desorption of vapors from the canister.

[0005] As an example, the FOH can be configured to consume vapors desorbed from the canister in a closed-loop system. In this example, heated air from the FOH flows to the canister to facilitate vapor release. Vapors from the canister can flow to the FOH for combustion. Additionally or alternatively, vapors from the canister can flow to the engine during certain conditions, such as engine start / stop or other events where an engine restart will occur after the canister is extracted. The vapors can be stored in the engine via adjusting the position of the engine valves and consumed during a subsequent restart. The operation of the FOH can consume less fuel than the engine while providing controlled treatment of vapors within the canister. By doing so, emissions from a vehicle including the FOH and the canister can be reduced.

[0006] It should be understood that the above summary is provided to introduce a series of concepts further described in the detailed description in a simplified form. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is uniquely defined by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to embodiments that address any disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Advantages described herein will be more fully understood by reading examples of embodiments referred to herein as detailed descriptions when read alone or with reference to the accompanying drawings, in which:

[0008] Figure 1 A high-level block diagram illustrating an example vehicle propulsion system is shown;

[0009] Figure 2 Shows Figure 1 An example engine system, a fuel system, and an evaporative emission control (EVAP) system included in an example vehicle system of;

[0010] Figure 3 An example of a fuel operated heater (FOH) system coupled to an EVAP system is shown;

[0011] Figure 4 A first method for operating a FOH of a FOH system is shown;

[0012] Figure 5 A second method for operating the FOH of a FOH system is shown; and

[0013] Figure 6 An operational sequence illustrating the conditions of the FOH system and the EVAP system is shown. DETAILED DESCRIPTION

[0014] The following description relates to systems and methods for an EVAP system for a vehicle. The vehicle may be at least a partially electric vehicle including an electric-only mode. Examples of vehicles and EVAP systems are described in Figure 1 and Figure 2 The EVAP system can be coupled to a fuel operated heater (FOH) system, such as Figure 3 The operation of the EVAP system and the FOH may be controlled via a controller. Figure 4 A first method for operating the FOH of a FOH system is shown. Figure 5 A second method for operating the FOH of a FOH system is shown. Figure 6 An operational sequence illustrating the conditions of the FOH system and the EVAP system is shown.

[0015] Figures 1 to 3An example configuration with relative positioning of various components is shown. In at least one example, if shown as being in direct contact or directly coupled to each other, such elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. As an example, components that are coplanarly in contact with each other may be referred to as coplanar contact. As another example, in at least one example, elements that are positioned apart from each other with only space therebetween and no other components may be referred to as such. As another example, elements that are shown as being above / below each other, on opposite sides or on the left / right side of each other may be referred to as such relative to each other. In addition, as shown in the accompanying drawings, in at least one example, the topmost element or the vertex of an element may be referred to as the "top" of a component, and the bottommost element or the bottommost point of an element may be referred to as the "bottom" of a component. As used herein, top / bottom, upper / lower, above / below may be relative to the vertical axis of the accompanying drawings, and are used to describe the positioning of the elements of the accompanying drawings relative to each other. For this reason, in one example, an element that is shown as being above other elements is located directly above other elements. As yet another example, the shapes of elements depicted within the drawings may be referred to as having these shapes (e.g., such as being round, straight, planar, curved, rounded, chamfered, angled, etc.). Additionally, in at least one example, elements shown as intersecting one another may be referred to as intersecting elements or intersecting one another. Further, in one example, elements shown as being within another element or shown as being outside another element may be referred to as such. It should be understood that one or more components referred to as being "substantially similar and / or identical" may differ from one another according to manufacturing tolerances (e.g., within a deviation of 1% to 5%).

[0016] Figure 1 An exemplary vehicle propulsion system 100 is shown. The vehicle propulsion system 100 includes a fuel combustion engine 110 and a motor 120. As a non-limiting example, the engine 110 includes an internal combustion engine and the motor 120 includes an electric motor. The motor 120 can be configured to utilize or consume a different energy source than the engine 110. For example, the engine 110 may consume a liquid fuel (e.g., gasoline) to produce an engine output, while the motor 120 may consume electrical energy to produce a motor output. Therefore, a vehicle having the propulsion system 100 may be referred to as a hybrid electric vehicle (HEV).

[0017] The vehicle propulsion system 100 can utilize a variety of different operating modes depending on the operating conditions encountered by the vehicle propulsion system. Some of these modes can enable the engine 110 to be maintained in an off state (e.g., set to a deactivated state) in which fuel combustion at the engine is stopped. For example, under selected operating conditions, when the engine 110 is deactivated, the motor 120 can propel the vehicle via the drive wheels 130 as indicated by arrow 122.

[0018] During other operating conditions, the engine 110 may be set to a deactivated state (as described above), and the motor 120 may be operated to charge the energy storage device 150. For example, the motor 120 may receive wheel torque from the drive wheels 130, as indicated by arrow 122, wherein the motor may convert the kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150, as indicated by arrow 124. This operation may be referred to as regenerative braking of the vehicle. Thus, in some embodiments, the motor 120 may provide a generator function. However, in other embodiments, the generator 160 may alternatively receive wheel torque from the drive wheels 130, wherein the generator may convert the kinetic energy of the vehicle into electrical energy for storage at the energy storage device 150 as indicated by arrow 162.

[0019] During still other operating conditions, the engine 110 may be operated by combusting fuel received from the fuel system 140 as indicated by arrow 142. For example, when the motor 120 is deactivated, the engine 110 may be operated to propel the vehicle via the drive wheels 130 as indicated by arrow 112. During other operating conditions, both the engine 110 and the motor 120 may each be operated to propel the vehicle via the drive wheels 130 as indicated by arrows 112 and 122, respectively. A configuration in which both the engine and the motor may selectively propel the vehicle may be referred to as a parallel vehicle propulsion system. It should be noted that in some embodiments, the motor 120 may propel the vehicle via a first set of drive wheels, while the engine 110 may propel the vehicle via a second set of drive wheels.

[0020] In other embodiments, the vehicle propulsion system 100 can be configured as a series-type vehicle propulsion system, in which the engine does not directly propel the drive wheels. Instead, the engine 110 can be operated to power the motor 120, which can in turn propel the vehicle via the drive wheels 130, as indicated by arrow 122. For example, during selected operating conditions, the engine 110 can drive the generator 160 as indicated by arrow 116, which can in turn do one or more of the following: supply electrical energy to the motor 120 as indicated by arrow 114 or to the energy storage device 150 as indicated by arrow 162. As another example, the engine 110 can be operated to drive the motor 120, which can in turn provide a generator function to convert the engine output into electrical energy, where the electrical energy can be stored at the energy storage device 150 for subsequent use by the motor.

[0021] Fuel system 140 may include one or more fuel 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 blend of two or more different fuels. For example, fuel tank 144 may be configured to store a blend of gasoline and ethanol (e.g., E10, E85, etc.) or a blend of gasoline and methanol (e.g., M10, M85, etc.), whereby these fuels or fuel blends may be delivered to engine 110, as indicated by arrow 142. Some other suitable fuels or fuel blends may be supplied to engine 110, where they may be burned at the engine to produce engine output. Engine output may be utilized to propel the vehicle as indicated by arrow 112 or to recharge energy storage device 150 via motor 120 or generator 160.

[0022] In some embodiments, the energy storage device 150 may be configured to store electrical energy that may be supplied to other electrical loads resident on the vehicle (in addition to the motor), including cabin heating and air conditioning, engine starting, headlights, cabin audio and video systems, etc. As a non-limiting example, the energy storage device 150 may include one or more batteries and / or capacitors.

[0023] The control system 190 may communicate with one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. The control system 190 may receive sensory feedback information from one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160. In addition, the control system 190 may send control signals to one or more of the engine 110, the motor 120, the fuel system 140, the energy storage device 150, and the generator 160 in response to this sensory feedback. The control system 190 may receive an indication of an operator-requested output of the vehicle propulsion system from the vehicle operator 102. For example, the control system 190 may receive sensory feedback from a pedal position sensor 194 in communication with a pedal 192. The pedal 192 may schematically refer to a brake pedal and / or a drive pedal.

[0024] As indicated by arrow 184, energy storage device 150 may periodically receive electrical energy from a power source 180 that resides external to the vehicle (e.g., not part of the vehicle). As a non-limiting example, vehicle propulsion system 100 may be configured as a plug-in hybrid electric vehicle (HEV), such that electrical energy may be supplied to energy storage device 150 from power source 180 via power transmission cable 182. During operation to recharge energy storage device 150 from power source 180, power transmission cable 182 may electrically couple energy storage device 150 and power source 180. When the vehicle propulsion system is operating to propel the vehicle, power transmission cable 182 may be disconnected between power source 180 and 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).

[0025] In other embodiments, the power transmission cable 182 may be omitted, where the power may be received wirelessly at the energy storage device 150 from the power source 180. For example, the energy storage device 150 may receive power from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. To this end, it should be appreciated that the energy storage device 150 may be recharged using any suitable method from a power source that does not form part of the vehicle, such as from solar or wind power. In this way, the motor 120 may propel the vehicle by utilizing an energy source different from the fuel utilized by the engine 110.

[0026] The fuel system 140 may periodically receive fuel from a fuel source residing outside the vehicle. As a non-limiting example, the vehicle propulsion system 100 may be refueled by receiving fuel via the fuel dispensing device 170, as indicated by arrow 172. In some embodiments, the fuel tank 144 may be configured to store the fuel received from the fuel dispensing device 170 until it is supplied to the engine 110 for combustion. In some embodiments, the control system 190 may receive an indication of the level of fuel stored at the fuel tank 144 via a fuel level sensor. The fuel level stored at the fuel tank 144 (e.g., as identified by the fuel level sensor) may be communicated to the vehicle operator, for example, via a fuel gauge or an indication in the vehicle instrument panel 196.

[0027] The vehicle propulsion system 100 may also include an ambient temperature / humidity sensor 198 and a roll stability control sensor, such as a lateral and / or longitudinal and / or yaw rate sensor 199. The vehicle dashboard 196 may include indicator lights and / or a text-based display in which messages are displayed to the operator. The vehicle dashboard 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 dashboard 196 may include a refueling button 197 that the vehicle operator may manually actuate or press to initiate a refueling. For example, as described in more detail below, in response to the vehicle operator actuating the refueling button 197, a fuel tank in the vehicle may be depressurized so that a refueling may be performed.

[0028] In an alternative embodiment, the vehicle instrument panel 196 may convey audio messages to the operator without displaying them. Additionally, the sensors 199 may include a vertical accelerometer to indicate road roughness. These devices may be connected to the control system 190. In one example, the control system may adjust engine output and / or wheel brakes in response to the sensors 199 to improve vehicle stability.

[0029] Figure 2 A schematic diagram of a vehicle system 206 is shown. Vehicle system 206 includes an engine system 208 coupled to an evaporative emission control system 251 and a fuel system 218. Emission control system 251 includes a fuel vapor container, such as fuel vapor canister 222, that can be used to capture and store fuel vapors. In some examples, vehicle system 206 may be a hybrid electric vehicle system, such as Figure 1 A vehicle propulsion system 100 is provided.

[0030] The engine system 208 may include an engine 210 having a plurality of cylinders 230. In one example, the engine 210 is Figure 1 Embodiment of engine 110. Engine 210 includes engine air intake 223 and engine exhaust 225. Engine air intake 223 includes throttle 262, which is fluidly coupled to engine intake manifold 244 via intake passage 242. Engine exhaust 225 includes exhaust manifold 248 leading to exhaust passage 235, which guides exhaust gas to atmosphere. Engine exhaust 225 may include one or more emission control devices 270, which may be installed in a close-coupled position in the exhaust port. 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 should be understood that other components may be included in the engine, such as various valves and sensors.

[0031] Fuel system 218 may include a fuel tank 220 coupled to a fuel pump system 221. In one example, fuel tank 220 includes Figure 1 The fuel tank 144 of the engine 210 may be provided. The fuel pump system 221 may include one or more pumps for pressurizing fuel for delivery to injectors of the engine 210, such as the example injector 266 shown. The fuel pump system 221 may also be configured to deliver fuel to a fuel operated heater (FOH) system. Although a single injector 266 is shown, additional injectors are provided for each cylinder. It should be appreciated that the fuel system 218 may be a returnless fuel system, a return fuel system, or various other types of fuel systems.

[0032] Vapors generated in fuel system 218 may be directed to evaporative emission control system 251, which includes fuel vapor canister 222, via vapor line 231 before being purged into engine air intake 223. Vapor 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 during certain conditions. For example, vapor recovery line 231 may be coupled to fuel tank 220 via one or more of conduits 271, 275, and 276, or a combination thereof.

[0033] Additionally, in some examples, one or more fuel tank ventilation valves may be located in conduits 271, 275, or 276. Among other functions, the fuel tank ventilation valve may allow a fuel vapor canister of an emission control system to be maintained at a low pressure or vacuum without increasing the fuel evaporation rate of the fuel tank (which would otherwise occur if the fuel tank pressure were reduced). For example, conduit 271 may include a fuel tank isolation valve (FTIV) 252. Conduit 275 may include a pressure relief valve (RV) 285. In one example, conduit 275 is a bypass conduit, wherein RV 285 is configured to allow vapors to flow to canister 222 when FTIV 252 is closed. Additionally, in some examples, vapor line 231 may be coupled to a fuel supply system 219. In some examples, fuel supply system 219 may include a fuel tank cap 205 for sealing the fuel filling system from the atmosphere. Fuel supply system 219 is coupled to fuel tank 220 via fuel filler pipe 211.

[0034] In addition, the refueling system 219 may include a refueling lock 245. In some embodiments, the refueling 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 205 in a closed position so that the fuel tank cap cannot be opened. For example, when the pressure or vacuum in the fuel tank 220 is greater than a threshold, the fuel tank cap 205 may remain locked via the refueling lock 245. In response to a refueling request, for example, the vehicle operator activates a refueling button on the vehicle dashboard (such as Figure 1 The fuel tank may be depressurized upon a request initiated by a refuel button 197 on a vehicle dashboard 196 of the vehicle, and the fuel tank may be unlocked after the pressure or vacuum in the fuel tank drops below a threshold. Herein, unlocking the refuel lock 245 may include unlocking the fuel tank cap 205. The fuel tank cap locking mechanism may be a latch or a clutch that prevents removal of the fuel tank cap when engaged. The latch or clutch may be electrically locked, for example, by a solenoid, or may be mechanically locked, for example, by a pressure diaphragm.

[0035] In some embodiments, refuel lock 245 may be a refuel pipe valve located at the mouth of fuel fill pipe 211. In such embodiments, refuel lock 245 may not prevent removal of fuel tank cap 205. Rather, refuel lock 245 may prevent a refuel pump from being inserted into fuel fill pipe 211. The refuel pipe valve may be electrically locked, such as by a solenoid, or mechanically locked, such as by a pressure diaphragm.

[0036] In some embodiments, refuel lock 245 may be a refuel door lock, such as a latch or clutch that locks a refuel door located in a body panel of the vehicle. The refuel door lock may be electrically locked, such as by a solenoid, or mechanically locked, such as by a pressure diaphragm.

[0037] In embodiments where an electrical mechanism is used to lock refuel lock 245, for example, when the fuel tank pressure drops below a pressure threshold, refuel lock 245 may be unlocked by a command from controller 212. In embodiments where a mechanical mechanism is used to lock refuel lock 245, for example, when the fuel tank pressure drops to atmospheric pressure, refuel lock 245 may be unlocked via a pressure gradient.

[0038] The emission control system 251 may include one or more fuel vapor canisters 222 (also referred to herein simply as canisters) filled with a suitable adsorbent, which is configured to temporarily capture fuel vapors (including vaporized hydrocarbons) generated during fuel tank refill operations and "running loss" vapors (i.e., fuel that vaporizes during vehicle operation). In one example, the adsorbent used is activated carbon. The emission control system 251 may also include a canister vent path or vent line 227 that can direct gases from the fuel vapor canister 222 to the atmosphere when storing or capturing fuel vapors from the fuel system 218. When the emission control system 251 includes more than one canister 222, the canisters may be arranged in series or in parallel. When the canisters are arranged in series, gases may be directed to a first canister in one or more canisters, then from the first canister to a second canister in one or more canisters, and so on for additional canisters in one or more canisters. When the filter canisters are arranged in parallel, the total volume of gas directed through more than one filter canister can be directed to the first filter canister or the second filter canister, or the total volume of gas can be divided into two volumes, wherein the first volume of the two volumes is directed through the first filter canister and the second volume of the two volumes is directed through the second filter canister.

[0039] Vent line 227 may also allow fresh air to be drawn into canister 222 via ventilation valve 229 as stored fuel vapors are purged from fuel system 218 to engine air intake 223 via purge line 228 and purge valve 261. For example, purge valve 261 may be normally closed, but may be opened during certain conditions (such as certain engine operating conditions) so that vacuum from engine intake manifold 244 is applied to the fuel vapor canister for purging. In some examples, vent line 227 may include an optional air filter 259 disposed therein upstream of canister 222. The flow of air and vapors between canister 222 and the atmosphere may be regulated by canister ventilation valve 229.

[0040] Undesirable evaporative emission detection routine can be intermittently performed by controller 212 on fuel system 218 to confirm that the fuel system is not degraded. Therefore, the undesirable evaporative emission detection routine can be performed when the engine is shut down (engine shut-down leak test) using the engine shut-down natural vacuum (EONV) generated by the change of temperature and pressure at the fuel tank after the engine is shut down and / or the vacuum supplemented from the vacuum pump. Alternatively, the undesirable evaporative emission detection routine can be performed by operating the vacuum pump and / or using the engine intake manifold vacuum when the engine is running. The test of undesirable evaporative emission can be performed by an evaporative leak check module (ELCM) 295 that is communicatively connected to controller 212. ELCM295 can be connected between canister 222 and ventilation valve 229 in ventilation line 227. ELCM 295 can include a vacuum pump configured to apply negative pressure to the fuel system when it is in a first configuration (such as when a leak test is implemented). ELCM 295 can also include a reference orifice and a pressure sensor 296. After applying vacuum to the fuel system, the change in pressure (e.g., absolute change or rate of change) at the reference orifice can be monitored and compared to a threshold value. Based on the comparison, undesirable evaporative emissions from the fuel system can be identified. The ELCM vacuum pump can be a reversible vacuum pump and is therefore configured to apply positive pressure to the fuel system when the bridge circuit is reversed, thereby placing the pump in a second configuration.

[0041] Canister 222 may include a first buffer zone 224 surrounding load port 213. Like canister 222, buffer zone 224 may also include an adsorbent. The volume of buffer zone 224 may be less than the volume of canister 222 (e.g., be a portion thereof). The adsorbent in buffer zone 224 may be the same as or different from the adsorbent in the canister (e.g., both may include charcoal). Buffer zone 224 may be located within canister 222 such that during canister loading through load port 213, fuel tank vapors are first adsorbed within the buffer zone, and then additional fuel tank vapors are adsorbed in the body of the canister when the buffer zone is saturated. In contrast, when canister 222 is purged (where air is drawn through vent line 227), fuel vapors are first desorbed from the canister (e.g., to a threshold amount) and then desorbed from the buffer zone. In contrast, when canister 222 is purged (where air is drawn through vent line 227), fuel vapors are first desorbed from the canister (e.g., to a threshold amount) and then desorbed from the buffer zone. In other words, the loading and unloading of the buffer zone 224 is not consistent with the loading and unloading of the canister. Therefore, the effect of the canister buffer zone is to suppress any fuel vapor spikes flowing from the fuel tank to the canister, thereby reducing the possibility of any fuel vapor spikes entering the engine or being released through the exhaust tailpipe.

[0042] Fuel tank 220 is fluidly coupled to canister 222 via outlet conduit 276 that branches from fuel tank isolation valve (FTIV) 252 that controls the flow of fuel tank vapors from fuel tank 220 and into canister 222 through inlet conduit 271. By adjusting the position of FTIV 252, the flow of fuel vapors from fuel tank 220 to canister 222 may be varied. FTIV 252 may be actuated to a first, open position that couples fuel tank 220 to canister 222 via conduit 276. In examples where emission control system 251 includes more than one canister 222 arranged in parallel, adjusting the position of FTIV 252 to a first position may direct the flow of fuel vapors from fuel tank 220 to the first canister, adjusting to a second position may direct the flow of fuel vapors from fuel tank 220 to the second canister, and adjusting to a third position may direct the flow of fuel vapors from fuel tank 220 to both the first canister and the second canister. The FTIV may also be actuated to a fourth, closed position.

[0043] For example, when emission control system 251 includes a canister 222, FTIV 252 may be actuated to a closed position that seals fuel tank 220 from canister 222, wherein no fuel vapors flow through conduit 276. Controller 212 may command the FTIV position based on fuel system conditions, including an operator request for refueling, fuel tank pressure, and canister load. In a second example, a 0.03" orifice is included in the position of FTIV 252 to restrict vapor flow to the canister.

[0044] In a configuration where the vehicle system 206 is a hybrid electric vehicle (HEV), the fuel tank 220 can be designed as a sealed fuel tank that can withstand pressure fluctuations typically encountered during normal vehicle operation and diurnal temperature cycles (e.g., a steel fuel tank). In addition, the size of the canister 222 can be reduced to account for the reduced engine operating time in a hybrid vehicle. However, for the same reason, HEVs may also have limited opportunities to perform fuel vapor canister purging operations. Therefore, the use of a sealed fuel tank with a closed FTIV (also known as NIRCOS or non-integrated refueling canister dedicated system) prevents diurnal and operating loss vapors from loading the fuel vapor canister 222 and limits fuel vapor canister loading to only via refueling vapors. The FTIV 252 can be selectively opened in response to a refueling request, thereby depressurizing the fuel tank 220 before fuel can be received into the fuel tank via the fill pipe 211. Specifically, when emission control system 251 includes a canister 222 , FTIV 252 may be actuated to a first open position to depressurize the fuel tank to the canister via first conduit 276 and canister load port 213 .

[0045] In some embodiments (not shown), a pressure control valve (PCV) (e.g., RV 285) may be configured in parallel with conduit 276 in a conduit coupling fuel tank 220 to canister 222. When included, the RV may be controlled by a powertrain control module (e.g., controller 212) using a pulse width modulation cycle to relieve any excess pressure built up in the fuel tank, such as when the engine is running. Additionally or optionally, such as in the case of a hybrid electric vehicle, the RV may be pulse width modulated to vent excess pressure in the fuel tank when the vehicle is operating in electric vehicle mode.

[0046] When transitioned to the second (open) position for an emission control system 251 having one canister 222, FTIV 252 allows fuel vapors to be vented from fuel tank 220 to canister 222. The second open position may be a fully open position, and the first open position may be a partially open position, such as a half-open position.

[0047] For emission control systems 251 having at least one canister 222 (including more than one canister 222 arranged in parallel), fuel vapors may be stored in canister 222, while air stripped from the fuel vapors exits into the atmosphere via canister vent valve 229. When engine conditions permit, fuel vapors stored in canister 222 may be purged to engine air intake 223 via purge valve 261. After the fuel tank is sufficiently depressurized (such as below a second threshold pressure), refuel lock 245 may be unlocked to open the fuel tank cap.

[0048] In the absence of input from the controller 212, the RV 285 may open during conditions where the fuel tank pressure exceeds a threshold fuel tank pressure. This may occur during conditions where the controller 212 is dormant, which may occur when the engine is off and / or when the vehicle is off. In prior art examples, ventilation events while the controller 212 is dormant may not be tracked, resulting in insufficient canister cleaning, which may cause vapors to be released into the atmosphere. This may be exacerbated in hybrid vehicles where the engine may be shut off for extended periods of vehicle operation. In one example, the evaporative emission control system 251 may be fluidly coupled to the FOH system via a first passage 302 and a second passage 304. About Figure 3 The FOH system is shown in greater detail.The FOH system may be operated to flow heated air to the canister 222 which may release vapors therefrom during desired conditions.

[0049] The vehicle system 206 may also include a control system 214 (such as Figure 1206 ). The control system 214 is shown as 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 an example, the sensors 216 may include an exhaust gas sensor 237 located upstream of the emission control device, an exhaust gas temperature or pressure sensor 233, a fuel tank pressure sensor (FTPT) or pressure sensor 291, a canister load sensor 243, and an ELCM pressure sensor 296. Thus, the pressure sensor 291 provides an estimate of the fuel system pressure. In one example, the fuel system pressure is a fuel tank pressure, such as the pressure within the fuel tank 220. Other sensors (such as pressure, temperature, air-fuel ratio, and composition sensors) may be coupled to various locations in the vehicle system 206. As another example, the actuators may include a fuel injector 266, a throttle 262, a FTIV 252, a refuel lock 245, a canister vent valve 229, and a purge valve 261. The control system 214 may include a controller 212. The controller may receive input data from various sensors, process the input data, and trigger the actuators in response to the processed input data based on instructions or coding programmed into the input data corresponding to one or more routines. Figure 1 to Figure 2 Various sensors receive signals and use Figure 1 to Figure 2 Various actuators are controlled to adjust engine operation based on received signals and instructions stored in the controller's memory.

[0050] For example, in response to an operator refueling request, the controller may obtain sensor input from a fuel tank pressure sensor (FTPT) 291 and compare it to a threshold value. If the pressure is above the threshold value, the controller may send a signal to command the FTIV 252 to a position that accelerates depressurization of the fuel tank. Among other things, based on the canister load (as estimated via sensor 243) and / or based on an estimated time to depressurize the fuel tank, the controller 212 may adjust the position of the FTIV 252 to depressurize the fuel vapors to the load port 213 of the canister 222. Once it is inferred that the fuel tank has been sufficiently depressurized based on the output of the fuel tank pressure sensor, the controller may send a signal to command the refuel lock 245 to open or release so that fuel may be received into the fuel tank 220 via the fuel fill pipe 211.

[0051] Now turn to Figure 3, which shows a FOH system 300. The FOH system 300 can be fluidly coupled to the evaporative emission control system 251 via a first channel 302 and a second channel 304. In one example, the first channel 302 is an inlet channel, and the second channel 304 is an outlet channel. The first channel 302 can intersect the extraction line 228 at the junction between the filter canister 222 and the extraction valve 261 at the first end. The first channel 302 can intersect the FOH inlet channel 306 at a position upstream of the FOH 310 relative to the air flow direction. The first valve 303 can be arranged in the first channel 302 and is configured to control the vapor flow from the filter canister 222 to the FOH inlet channel 306. The first valve 303 can be adjusted to a fully closed position, a fully open position, or any position therebetween based on the desorption of vapor from the canister 222. Additionally or alternatively, the position of the first valve 303 can be adjusted based on the operation of the engine.

[0052] The FOH 310 can be configured to burn fuel. When burning fuel, the FOH 310 can heat air. The heated air can be exhausted through the FOH outlet 312. The combustion gases can be exhausted from the FOH 310 via an exhaust outlet 314 that is separate from the FOH outlet. The exhaust outlet 314 can direct the combustion gases directly to the atmosphere. In one example, the exhaust outlet 314 can additionally or alternatively direct the combustion gases to Figure 2 The combustion gases of the FOH 310 are not mixed with the ambient air or heated air flowing therethrough. In one example, the FOH 310 may include at least one combustion chamber 311 having an ignition device 313. Fuel and air may be supplied to the combustion chambers 311, wherein the air may flow outside and around the at least one combustion chamber 311. The combustion chambers 311 may be hermetically sealed with passages that allow ambient air and heated air to flow through the FOH 310. The FOH 310 may be supplied with fuel via a fuel pump (e.g., Figure 2 221 or a separate fuel pump) receives fuel. Additionally or alternatively, fuel vapor from canister 222 may be a fuel source for FOH 310. Thus, in one example, FOH 310 may include a clean air inlet 315, wherein air provided from the clean air inlet is heated and not mixed with fuel vapor or liquid fuel. In one example, the clean air inlet may be a single continuous channel with FOH outlet 312, wherein sections of the channel may wrap or extend proximally to cylinder 311. The air may be heated due to combustion, wherein the heated air is directed to FOH outlet 312.

[0053] The cabin heating valve 316 can be disposed in the FOH outlet 312 at a position downstream of the junction between the FOH outlet 312 and the second passage 304. The cabin heating valve 316 can be adjusted to a fully closed position, a fully open position, or any position therebetween based on a cabin heating request. The position of the cabin heating valve 316 can be further adjusted based on engine operation in conjunction with the cabin heating request. In one example, the cabin heating valve can control heated air flow to the interior of the vehicle cabin.

[0054] The second valve 305 can be arranged in the second passage 304. The second valve 305 is configured to control the heated air flow from the FOH outlet 312 to the junction between the second passage 304 and the ventilation line 227. In one example, the second passage 304 intersects the ventilation line 227 at a position between the filter canister 222 and the ELCM 295 at the first end. The second end of the second passage 304, which is opposite to the first end, intersects the FOH outlet 312 at the junction between the FOH 310 and the cabin heating valve 316. In one example, the second valve 305 is a check valve that is configured to open in the presence of heated air entering the second passage 304 from the FOH outlet 312. In this example, the second valve 305 can be thermostatically controlled via wax or a similar element. Additionally or alternatively, the second valve 305 can be controlled by a controller and configured to move to a fully closed position, a fully open position, or any position therebetween.

[0055] Figure 3 The arrows included in indicate directions that gases may flow during various conditions of FOH system 300 and evaporative emission control system 251. The positions of purge valve 261, first valve 303, second valve 305, and cabin heating valve 316 may be adjusted based on at least the condition of canister 222. Figure 4 Methods and Figure 5 The method of FIG. 1 shows an operation for releasing vapors from canister 222 via heated air from FOH 310 during engine off conditions to control vapor emissions and load from canister 222. By doing so, vehicle emissions may be reduced. Vapors released from canister 222 may be stored in cylinders of the engine prior to engine start and / or consumed by FOH 310 as it heats air.

[0056] Now turn to Figure 4 , which shows a method 400 for flowing heated air to a canister via the FOH. Canister vapors flow to and are stored in the engine cylinders prior to engine restart. Instructions for implementing method 400 and the remaining methods included herein may be executed by a controller based on instructions stored on a memory of the controller and in conjunction with signals received from sensors of the engine system, such as those described above with reference to Figures 1 to 3 The controller may employ engine actuators of the engine system to adjust engine operation according to the methods described below.

[0057] Method 400 begins at 402 and includes determining current operating parameters. Current operating parameters may include, but are not limited to, one or more of manifold vacuum, engine speed, engine temperature, vehicle speed, and air / fuel ratio.

[0058] At 404, method 400 may include determining an ambient temperature. The ambient temperature may be determined via a temperature sensor mounted to the vehicle. The temperature sensor may be remote from other heat generating devices so that heat released by other vehicle components may not affect the temperature reading of the temperature sensor. Additionally or alternatively, the ambient temperature may be provided by a weather service via a wireless connection. In some examples, the mobile device may provide the ambient temperature via a wireless connection. The ambient temperature may also be based on sunlight, wind, ground, rain, etc. For example, direct sunlight may increase the ambient temperature reading. Additionally or alternatively, when a relatively large amount of sunlight is directed toward the vehicle, if the ground is pavement, the ambient temperature reading may increase compared to when the ground is dirt.

[0059] At 406, method 400 may include determining whether the ambient temperature is below a determined ambient temperature. The determined ambient temperature may be based on a temperature at which fuel vapors may be released from the canister. During certain conditions, such as when the engine is off, it may be desirable to dispose of canister vapors due to the ambient temperature being greater than or equal to the determined ambient temperature. If the ambient temperature is not below the determined ambient temperature, method 400 may proceed to Figure 5 502.

[0060] If the ambient temperature is below the determined ambient temperature, then at 408, method 400 may include determining whether a canister purge is requested during an engine shut-down event. In one example, the engine may be shut down due to a start / stop event. If a canister purge is not requested or if a canister purge is requested and the engine is on, then at 410, method 400 may include not activating the FOH.

[0061] If canister purge is requested and the engine is off, at 412 , method 400 may include opening a canister purge valve (CPV), such as Figure 2 purge valve 261. To this end, vapors from the canister can flow to the engine via the purge line and the open CPV.

[0062] At 414, method 400 may include starting the FOH and opening the second valve. To this end, the FOH may heat air, and the second valve may direct the heated air to the canister. The heated air may help release vapors from the canister. Fuel from the fuel tank may be provided to the FOH via a pump, and combustion therein may be initiated.

[0063] At 416 , method 400 may include adjusting the cabin heating valve position based on the cabin heating request. As the cabin heating request increases, the cabin heating valve may move to a more open position.

[0064] In one example, a setting of the FOH, such as fuel fill or mass airflow, may be adjusted based on one or more of a cabin heating request, an estimate of the engine shutoff duration, and a canister load. For example, the fuel fill of the FOH may be increased in response to one or more of an increase in the cabin heating request, a decrease in the estimate of the engine shutoff duration, and a relatively high canister load. If the canister load is above a threshold canister load, the canister load may be relatively high. Additionally or alternatively, the canister load may affect the desorption rate, wherein the desorption rate may increase when the canister load is relatively high. The estimate of the engine shutoff duration may be based on vehicle operator driving behavior, time of day, traffic conditions, vehicle location, etc. For example, if the vehicle operator stops at a traffic light, the duration of the stop may be known based on previous stops at similar times of the day and similar traffic conditions.

[0065] In one real-world example, if the canister load is above a threshold canister load and the estimated value of the engine off duration is relatively short, the FOH may be operated at a relatively high temperature with relatively high air and fuel amounts. Conversely, if the canister load is below the threshold canister load and / or if the estimated value of the engine off duration is relatively long, the FOH may be operated at a relatively low temperature with relatively low air and / or fuel amounts.

[0066] At 418, method 400 may optionally include closing the first valve. In one example, if the vehicle is a pure ICE vehicle and does not include an electric motor, the first valve and the first passage may not be included in the FOH system. However, the first valve and the first passage are included in a hybrid vehicle layout that includes an electric motor and an ICE. The first valve may be closed to prevent vapors from the canister from flowing to the FOH. In one example, the first valve may be closed when an engine restart is scheduled to occur after the purging event of method 400. To this end, the vapors may be used for combustion in the engine to facilitate movement of the vehicle.

[0067] If an engine restart is not planned, vapors may be directed to the FOH in closed loop operation. The CPV may be closed and the first valve may be opened to allow vapors desorbed from the canister to flow to the FOH. Figure 5 The closed loop operation is described in more detail.

[0068] In some examples, additionally or alternatively, vapor from the canister may be directed to each of the engine and the FOH. The CPV and the first valve may be moved to a partially open position to facilitate vapor flow to the engine and the FOH, respectively. In one example, the amount of vapor flow to the FOH may be adjusted based on engine combustion conditions during a previous engine restart event after a purging event. For example, if engine knock or other conditions occur during an engine restart, more or less vapor may be directed to the FOH.

[0069] At 420, method 400 may include flowing heated air from the FOH to the canister. In one example, ambient air is heated by the FOH and directed to the canister through a second passage. The heated air may release vapors from the canister.

[0070] At 422, method 400 may include flowing canister vapors into engine cylinders. In one example, the intake valves of the engine cylinders are opened and the exhaust valves of the engine cylinders are closed. In this way, vapors can be stored in the engine cylinders and consumed after the engine is restarted. Fueling parameters can be adjusted during engine restart to account for fuel vapors stored therein. Thus, in one example, engine fueling after an engine restart after an engine stop can be adjusted based on one or more of the canister vapor load, desorption rate, FOH fueling, cabin heating request, and second valve position. For example, engine fueling after an engine restart can be reduced in response to an increase in FOH fueling. Additionally or alternatively, engine fueling after an engine restart can be reduced in response to a decrease in canister vapor load to account for vapors from a carbon canister in the engine. FOH can be deactivated after restarting the engine.

[0071] Now turn to Figure 5 , which shows a method 500 for consuming vapors from a canister via a FOH when breakthrough may occur. The method 500 is Figure 4406 is "No" and then starts at 502. To this end, the ambient temperature is higher than the determined ambient temperature, and at 502, method 500 includes determining whether the probability of canister penetration is higher than a threshold probability. The probability of canister penetration may be based on a combination of ambient temperature, canister load, and the period of time that the engine has been shut down. For example, the probability of canister penetration increases as the ambient temperature increases and / or as the canister load increases and / or as the period of time that the engine is shut down (e.g., the engine shut-down duration) increases. The threshold probability may be based on a percentage of the probability that vapor can escape from the canister, such as 50% or 70% or 90%. In one example, the relative canister load may be determined based on a combination of the canister load and the ambient temperature. If the probability of canister penetration is not higher than the threshold probability, then at 504, method 500 may include not allowing canister vapor to flow to the FOH. To this end, the FOH may not be started.

[0072] If the canister breakthrough likelihood is not above the threshold likelihood, at 506, method 500 may include determining whether the engine is off. The engine may be off during start / stop or all-electric operation of the vehicle. Additionally or alternatively, the engine may be off when the vehicle is turned off in response to the vehicle operator pressing an ignition button and / or removing an ignition key. If the engine is not off, method 500 proceeds to 504, as described above. When the engine is on, the FOH may not be used to consume canister vapors or facilitate vapor desorption.

[0073] If the engine is off, then at 508, method 500 may include starting the FOH. Starting the FOH may include flowing fuel and air to at least one cylinder of the FOH. Fuel may be provided from a fuel tank via a pump. Combustion may occur within the FOH, which may be used to heat the air.

[0074] At 510, method 500 can include opening a first valve. To this end, the first passage can allow gas to flow from the extraction line into an inlet of the FOH.

[0075] At 512 , method 500 may include opening the second valve.Heated air from the FOH may be directed to the canister, which may cause vapors to be released from the canister.

[0076] At 514 , method 500 may include closing the CPV. Vapors from the canister are blocked from flowing to the intake of the engine.

[0077] At 516, method 500 may include switching the ELCM to a pressure mode. The pressure mode may be used to control the temperature of the warm air flowing to the canister. Additionally or alternatively, a switching valve in the ELCM may be used to control the temperature.

[0078] At 518, method 500 may include flowing vapor from the canister to the FOH. The vapor may flow into a combustion chamber of the FOH and combust. To this end, the vapor may be consumed so that unburned hydrocarbons are not released into the atmosphere. In one example, the fuel charge of the FOH may be adjusted based on the desorption rate of the canister. For example, as the desorption rate increases, the fuel charge of the FOH may be reduced to account for more vapor flowing to the FOH compared to a lower desorption rate.

[0079] At 520, method 500 may include flowing heated air from the FOH to the canister. The heated air may be hotter than ambient air and may facilitate release of vapors from adsorbents of the canister. The FOH may remain active until one or more of an engine on, a vehicle off, a canister load falling below a lower limit, and an ambient temperature falling below a threshold ambient temperature occurs.

[0080] Turning now to 6, an operating sequence is graphically illustrated via graph 600, which illustrates changes in the condition of the FOH system and the evaporative emission control system when the canister is cleaned (e.g., vapors are removed therefrom). Graph 610 illustrates whether the FOH is on or off. Graph 620 illustrates the ambient temperature. Graph 630 illustrates the canister load, and dashed line 632 illustrates the threshold canister load. Graph 640 illustrates whether the engine is on or off. Prior to t1, the engine and FOH are turned off. The ambient temperature rises to a relatively high temperature, which causes the relative canister load to increase. The relative canister load can cope with the actual canister load and the ambient temperature. In one example, the actual canister load is determined via a hydrocarbon sensor mounted at the canister port. Additionally or alternatively, the actual canister load can be estimated based on an engine operating cycle and / or a FOH operating cycle.

[0081] At t1, the relative canister load is equal to the threshold canister load. The FOH is activated. Between t1 and t2, the FOH begins to heat air and flow the heated air to the canister. As vapors from the canister are directed to the FOH, the relative canister load decreases. The FOH may combust vapors in conjunction with fuel delivered from the vehicle fuel tank.

[0082] At t2, the relative canister load is relatively low and below the threshold canister load. For this reason, the FOH is deactivated and no longer consumes fuel or heats air. After t2, as the engine remains off, the canister load begins to increase.

[0083] The present disclosure provides support for a method that includes heating air using a fuel operated heater (FOH), and directing the heated air from the FOH to a canister in an evaporative emission control system. A first example of the method also includes directing vapor from the canister to the FOH. A second example of the method (optionally including the first example) also includes wherein the FOH fuels the vapor. A third example of the method (optionally including one or more of the previous examples) also includes: wherein using the FOH also includes deactivating the engine. A fourth example of the method (optionally including one or more of the previous examples) also includes: directing heated air from the FOH to a vehicle cabin interior. A fifth example of the method (optionally including one or more of the previous examples) also includes: directing vapor from the canister to an engine, wherein an intake valve of the engine is open, and an exhaust valve of the engine is closed.

[0084] The present disclosure provides additional support for a system including an engine, an evaporative emission control system including a canister, a fuel tank, and a fuel operated heater (FOH) fluidly coupled to the canister. A first example of the system also includes: wherein a controller has computer-readable instructions stored in its non-transitory memory, and the computer-readable instructions, when executed, enable the controller to flow heated air from the FOH to the canister during a purge event. A second example of the system (optionally including the first example) also includes: wherein the instructions also cause the controller to close a first valve in a first passage and open a canister purge valve to allow vapor to flow only from the canister to the engine. A third example of the system (optionally including one or more of the foregoing examples) also includes: wherein the instructions also cause the controller to adjust the fueling of the engine based on one or more of the fueling of the FOH and a cabin heating request during the purge event after an engine restart following the purge event. A fourth example of the system (optionally including one or more of the foregoing examples) also includes: wherein the controller has computer-readable instructions stored in its non-transitory memory, the computer-readable instructions, when executed, enabling the controller to flow heated air from the FOH to the canister in response to an ambient temperature being above a threshold temperature. A fifth example of the system (optionally including one or more of the foregoing examples) also includes: wherein the instructions also cause the controller to adjust a position of a first valve in a first passage to cause vapor to flow from the canister to the FOH, and wherein the instructions also cause the controller to adjust a position of a second valve in a second passage to cause heated air to flow from the FOH to the canister. A sixth example of the system (optionally including one or more of the foregoing examples) also includes: wherein the instructions also cause the controller to adjust fueling of the FOH based on one or more of engine stop duration, canister load, ambient temperature, and a canister desorption rate. A seventh example of the system (optionally including one or more of the preceding examples) further includes: wherein the FOH is fluidly coupled to the canister via a first passage coupled to a purge line of the canister and a second passage coupled to a vent line of the canister. An eighth example of the system (optionally including one or more of the preceding examples) further includes: wherein the first passage includes a first valve configured to control an amount of vapor flowing to the FOH.

[0085] The present disclosure provides another support for a method, which includes fueling a fuel-operated heater (FOH) and directing heated air from the FOH to a canister disposed in an evaporative emission control system. The first example of the method also includes causing vapor to flow from the canister to the FOH via a purge line and a first passage, wherein the fueling of the FOH is adjusted based on a desorption rate of the canister. The second example of the method (optionally including the first example) also includes causing vapor to flow from the canister to the engine via a purge line, and also includes adjusting the fueling of the engine based on one or more of the FOH fueling and the desorption rate of the canister after the engine is restarted. The third example of the method (optionally including one or more of the preceding examples) also includes: wherein each of the canister and the FOH is fluidly coupled to a fuel tank. The fourth example of the method (optionally including one or more of the preceding examples) also includes: wherein the fueling of the FOH is adjusted based on a cabin heating request.

[0086] It should be noted that the example control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in a non-transitory memory and can be executed by a control system including a controller in combination 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.). Therefore, the various actions, operations and / or functions shown may be executed in the sequence shown, executed in parallel, or omitted in some cases. Similarly, the processing order is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the actions, operations and / or functions shown may be repeatedly performed according to the specific strategy used. In addition, the actions, operations and / or functions may be graphically represented as codes in a non-transitory memory of a computer-readable storage medium to be programmed into an engine control system, wherein the actions are implemented by executing instructions in a system including various engine hardware components in conjunction with an electronic controller.

[0087] It should be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific embodiments should not be construed in a limiting sense, as many variations are possible. For example, the above techniques may be applied to V-6, I-4, I-6, V-12, opposed 4, 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.

[0088] As used herein, unless otherwise specified, the term "about" is interpreted to mean a range of ±5%.

[0089] The appended claims particularly point out certain combinations and subcombinations regarded as 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 in the subject matter of the present disclosure.

[0090] According to the present invention, a method includes heating air using a fuel operated heater (FOH); and directing the heated air from the FOH to a canister in an evaporative emission control system.

[0091] In one aspect of the invention, the method includes directing vapor from the canister to the FOH.

[0092] In one aspect of the invention, the FOH combusts the vapor.

[0093] In one aspect of the invention, using the FOH further comprises deactivating the engine.

[0094] In one aspect of the invention, the method includes directing heated air from the FOH to a vehicle cabin interior.

[0095] In one aspect of the invention, the method includes directing vapors from the canister to an engine, wherein an intake valve of the engine is open and an exhaust valve of the engine is closed.

[0096] According to the present invention, a system is provided having: an engine; an evaporative emission control system including a canister; a fuel tank; and a fuel operated heater (FOH) fluidly coupled to the canister.

[0097] According to an embodiment, the invention also features a controller having computer-readable instructions stored in its non-transitory memory that, when executed, enable the controller to flow heated air from the FOH to the canister during a purge event.

[0098] According to an embodiment, the instructions further cause the controller to close a first valve in a first passage and open a canister purge valve to allow vapors to flow only from the canister to the engine.

[0099] According to an embodiment, the instructions further cause the controller to adjust fueling of the engine following an engine restart following the purging event based on one or more of fueling of the FOH and a cabin heating request during the purging event.

[0100] According to an embodiment, the present invention is also characterized by a controller having computer-readable instructions stored in its non-transitory memory, which when executed enable the controller to flow heated air from the FOH to the filter canister in response to the ambient temperature being above a threshold temperature.

[0101] According to an embodiment, the instructions further cause the controller to adjust a position of a first valve in a first passage to allow vapor to flow from the canister to the FOH, and wherein the instructions further cause the controller to adjust a position of a second valve in a second passage to allow heated air to flow from the FOH to the canister.

[0102] According to an embodiment, the instructions further cause the controller to adjust fueling of the FOH based on one or more of engine stop duration, canister loading, ambient temperature, and a canister desorption rate.

[0103] According to an embodiment, the FOH is fluidly coupled to the canister via a first passage coupled to a purge line of the canister and a second passage coupled to a vent line of the canister.

[0104] According to an embodiment, the first passage comprises a first valve configured to control an amount of vapor flowing to the FOH.

[0105] According to the present invention, a method includes fueling a fuel operated heater (FOH); and directing heated air from the FOH to a canister disposed in an evaporative emission control system.

[0106] In one aspect of the invention, the method includes flowing vapor from the canister to the FOH via a purge line and a first passage, wherein fueling the FOH is adjusted based on a desorption rate of the canister.

[0107] In one aspect of the invention, the method includes flowing vapor from the canister to an engine via a purge line, and further includes adjusting fueling of the engine after an engine restart based on one or more of the FOH fueling and a desorption rate of the canister.

[0108] In one aspect of the present invention, each of the canister and the FOH is fluidly coupled to a fuel tank.

[0109] In one aspect of the invention, fueling of the FOH is adjusted based on a cabin heating request.

Claims

1. A method comprising: Heating the air using a fuel operated heater (FOH); as well as The heated air is directed from the FOH to a canister in an evaporative emission control system.

2. The method of claim 1 further comprising directing vapor from the canister to the FOH.

3. The method of claim 2, wherein the FOH combusts the vapor.

4. The method of claim 1, wherein using the FOH further comprises deactivating an engine.

5. The method of claim 1 further comprising directing heated air from the FOH to a vehicle cabin interior. 6 . The method of claim 1 , further comprising directing vapors from the canister to an engine, wherein an intake valve of the engine is open and an exhaust valve of the engine is closed.

7. A system comprising: engine; evaporative emission control system including canister; Fuel tank; as well as A fuel operated heater (FOH) is fluidly coupled to the canister.

8. The system of claim 7, further comprising a controller having computer readable instructions stored in a non-transitory memory thereof that, when executed, enable the controller to flow heated air from the FOH to the canister during a purge event.

9. The system of claim 8, wherein the instructions further cause the controller to close a first valve in a first passage and open a canister purge valve to allow vapor to flow only from the canister to the engine.

10. The system of claim 8, wherein the instructions further cause the controller to adjust fueling of the engine after an engine restart following the purging event based on one or more of fueling of the FOH and a cabin heating request during the purging event.

11. The system of claim 7 further comprising a controller having computer readable instructions stored in a non-transitory memory thereof, the computer readable instructions when executed enabling the controller to flow heated air from the FOH to the canister in response to an ambient temperature being above a threshold temperature.

12. The system of claim 11, wherein the instructions further cause the controller to adjust a position of a first valve in a first passage to allow vapor to flow from the canister to the FOH, and wherein the instructions further cause the controller to adjust a position of a second valve in a second passage to allow heated air to flow from the FOH to the canister.

13. The system of claim 11 wherein the instructions further cause the controller to adjust fueling of the FOH based on one or more of engine stop duration, canister loading, the ambient temperature, and a desorption rate of the canister.

14. The system of claim 7, wherein the FOH is fluidly coupled to the canister via a first passage coupled to a purge line of the canister and a second passage coupled to a vent line of the canister.

15. The system of claim 14, wherein the first passage comprises a first valve configured to control an amount of vapor flowing to the FOH.

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