METHOD AND SYSTEMS FOR AN EVAPORATIVE EMISSION SYSTEM

Abstract

Procedures and systems for a fuel system are provided. In one example, a procedure might involve adjusting the operation of a fuel-operated heating device (FOH) in response to a canister condition. The FOH is switched on and configured to direct heated air toward the canister to promote the desorption of any fuel vapors stored within it.

Description

FIELD OF TECHNOLOGY

[0001] This description generally relates to methods and systems for an evaporative emission control system of a vehicle. GENERAL STATE OF THE ART

[0002] Vehicle fuel systems include evaporative emission control (EVAP) systems designed to reduce the release of fuel vapors into the atmosphere. For example, vaporized hydrocarbons (HC) from a 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 operating, the evaporative emission control system allows the vapors to be purged into the engine intake manifold for use as fuel. Fuel vapors can be generated as refueling, lost-service, hot soak, and daytime vapors. In a hybrid vehicle, the fuel vapors stored in the canister are primarily refueling vapors.

[0003] Vehicle manufacturers may increase the electric capability of one or more vehicles in a fleet. Expanding vehicle electric capabilities may result in reduced engine operating times and therefore reduced opportunities for fuel vapors to be consumed during canister venting. Additionally, non-hybrid vehicles, such as internal combustion engine (ICE)-only vehicles, may be equipped with start-stop and other features to reduce engine runtime. Each of these benefits presents challenges to the frequency with which canister cleaning can occur. Thus, a method and system different from those currently in place may be desired to achieve various goals. SUMMARY

[0004] In one example, the problems described above may be addressed by a method of 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. In this way, the FOH may promote the desorption of vapors from the canister.

[0005] As one example, the FOH may be configured to consume vapors desorbed from the canister in a closed-loop system. In such an example, heated air flows from the FOH to the canister to promote vapor release. The vapors from the canister may flow to the FOH for combustion. Additionally or alternatively, the vapors may flow from the canister to an internal combustion engine under certain conditions, such as during an engine start / stop or other event where an engine restart occurs after purging the canister. The vapors may be stored in the internal combustion engine by adjusting a position of an engine valve and consumed during a subsequent restart. Operation of the FOH may consume less fuel than the internal combustion engine while providing controlled treatment of vapors within the canister.This can reduce emissions from a vehicle, including the FOH and the canister.

[0006] It should be understood that the foregoing summary is provided to introduce, in simplified form, a selection of concepts that are described in more detail in the detailed description. It is not intended to identify important or significant features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any of the disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The advantages described in this document will become more fully apparent from reading an example of an embodiment, referred to in this document as the detailed description, when read alone or with reference to the drawings, in which: Fig. 1 shows a high-level block diagram illustrating an exemplary vehicle propulsion system; Fig. 2 shows an exemplary internal combustion engine system, fuel system, and evaporative emission control (EVAP) system used in the exemplary vehicle system of Fig. 1 are included; Fig. 3 shows an example of a system with a fuel-fired heater (FOH) coupled to the EVAP system; Fig. 4 shows a first method for operating a FOH of the FOH system; Fig. 5 shows a second method for operating the FOH of the FOH system; and Fig. Figure 6 shows an operating sequence illustrating FOH system and EVAP system conditions. DETAILED DESCRIPTION

[0008] The following description relates to systems and methods for an EVAP system of a vehicle. The vehicle may be an at least partially electric vehicle including an all-electric mode. An example of the vehicle and EVAP system is described in Fig. 1 and Fig. 2. The EVAP system can be used as shown in Fig. 3, be coupled to a system with a fuel-fired heater (FOH). The operation of the EVAP system and the FOH can be controlled via a controller. Fig. 4 shows a first method for operating a FOH of the FOH system. Fig. Figure 5 shows a second method for operating the FOH of the FOH system. Fig. Figure 6 shows an operating sequence illustrating FOH system and EVAP system conditions.

[0009] The Fig. 1-3 show example configurations with relative positioning of the various components. When shown as directly touching or directly coupled to one another, such elements may be referred to as directly touching or directly coupled to one another, respectively, in at least one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to one another, respectively, in at least one example. As one example, components that are in surface-sharing contact with one another may be referred to as being in surface-sharing contact. As another example, elements that are positioned apart from one another, with only a space between them and no other components, may be so referred to in at least one example.As yet another example, elements shown above / below each other, on opposite sides of each other, or left / right of each other may be so referred to relative to each other. Further, as shown in the figures, in at least one example, a topmost element or point of an element may be referred to as a "top" of the component, and a bottommost element or point of the element may be referred to as a "bottom" of the component. As used herein, top / bottom, upper / lower, over / under may be relative to a vertical axis of the figures and may be used to describe the positioning of elements of the figures relative to each other. Thus, in one example, elements shown above other elements are positioned vertically above the other elements.As yet another example, shapes of the elements depicted within the figures may be referred to as having these shapes (such as circular, straight, planar, curved, rounded, beveled, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another in at least one example. Still further, an element shown inside another element or outside another element may be referred to as such in an example. It is understood that one or more components referred to as "substantially similar and / or identical" may differ from one another according to manufacturing tolerances (e.g., within 1-5% variation). Fig. 1 illustrates an example vehicle propulsion system 100. The vehicle propulsion system 100 includes a fuel-burning engine 110 and an electric motor 120. As a non-limiting example, the engine 110 comprises an internal combustion engine, and the electric motor 120 comprises an electric motor. The electric motor 120 may 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 electric motor 120 may consume electrical energy to produce an electric motor output. Accordingly, a vehicle including the propulsion system 100 may be referred to as a hybrid electric vehicle (HEV).

[0010] The vehicle propulsion system 100 may utilize a variety of different operating modes depending on the operating conditions the vehicle propulsion system is subjected to. Some of these modes may allow the engine 110 to be maintained in a deactivated state (e.g., set to a deactivated state), in which the combustion of fuel in the engine is suspended. For example, under selected operating conditions, the electric motor 120 may propel the vehicle via a drive wheel 130, as indicated by arrow 122, while the engine 110 is deactivated.

[0011] During other operating conditions, the engine 110 may be set to a deactivated state (as described above), while the electric motor 120 may be operated to charge an energy storage device 150. For example, the electric motor 120 may receive wheel torque from the drive wheel 130, as indicated by arrow 122, and the electric motor may convert the vehicle's kinetic energy into electrical energy for storage in the energy storage device 150, as indicated by arrow 124. This process may be referred to as regenerative braking of the vehicle. Thus, in some embodiments, the electric motor 120 may provide a generator function.However, in other embodiments, a generator 160 may instead receive wheel torque from the drive wheel 130, where the generator may convert the vehicle's kinetic energy into electrical energy for storage in the energy storage device 150, as indicated by arrow 162.

[0012] During still other operating conditions, the engine 110 may be operated by combusting fuel received from a fuel system 140, as indicated by an arrow 142. For example, the engine 110 may be operated to propel the vehicle via the drive wheel 130, as indicated by arrow 112, while the electric motor 120 is off. During further operating conditions, both the engine 110 and the electric motor 120 may each be operated to propel the vehicle via the drive wheel 130, as indicated by arrows 112 and 122, respectively. A configuration in which both the engine and the electric motor can selectively propel the vehicle may be referred to as a parallel-type vehicle propulsion system.It should be noted that in some embodiments, the electric motor 120 may propel the vehicle through a first set of drive wheels and the engine 110 may propel the vehicle through a second set of drive wheels.

[0013] In further embodiments, the vehicle propulsion system 100 may be configured as a series-type vehicle propulsion system, where the engine does not directly drive the drive wheels. Rather, the engine 110 may operate to power the electric motor 120, which in turn may propel the vehicle via the drive wheel 130, as indicated by arrow 122. For example, during selected operating conditions, the engine 110 may drive the generator 160, as indicated by arrow 116, which in turn may supply electrical energy to one or more of the electric motor 120, as indicated by arrow 114, or the energy storage device 150, as indicated by arrow 162.As another example, the engine 110 may be operated to drive the electric motor 120, which in turn may provide a generator function to convert the engine output into electrical energy, where the electrical energy may be stored in the energy storage device 150 for later use by the electric motor.

[0014] The fuel system 140 may include one or more fuel tanks 144 for storing fuel onboard the vehicle. For example, the fuel tank 144 may store one or more liquid fuels, including, but not limited to, gasoline, diesel, and alcohol fuels. In some examples, the fuel may be stored onboard the vehicle as a mixture of two or more different fuels. For example, the 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.), which fuels or fuel mixtures may be delivered to the engine 110, as indicated by arrow 142. Other suitable fuels or fuel mixtures may be supplied to the engine 110, which may be combusted in the engine to produce an engine output.The engine output may be used to propel the vehicle, as indicated by arrow 112, or to recharge the energy storage device 150 via the electric motor 120 or the generator 160.

[0015] In some embodiments, the energy storage device 150 may be configured to store electrical energy that may be supplied to other electrical loads (other than the electric motor) onboard the vehicle, including cabin heating and air conditioning, engine starting, headlights, cabin video and audio systems, etc. As a non-limiting example, the energy storage device 150 may include one or more batteries and / or capacitors.

[0016] A control system 190 may communicate with one or more of the engine 110, the electric 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 electric motor 120, the fuel system 140, the energy storage device 150, and the generator 160. Further, in response to this sensory feedback, the control system 190 may send control signals to one or more of the engine 110, the electric motor 120, the fuel system 140, the energy storage device 150, and the generator 160. The control system 190 may receive an indication of an operator-requested output of the vehicle propulsion system from a vehicle operator 102. For example, the control system 190 may receive sensory feedback from a pedal position sensor 194 that communicates with a pedal 192.The pedal 192 may schematically refer to a brake pedal and / or an accelerator pedal.

[0017] The 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, the vehicle propulsion system 100 may be configured as a plug-in hybrid electric vehicle (HEV), where electrical energy may be supplied to the energy storage device 150 from the power source 180 via an electrical energy transmission cable 182. During a charging operation of the energy storage device 150 from the power source 180, the electrical transmission cable 182 may electrically couple the energy storage device 150 and the power source 180. While the vehicle propulsion system is operating to propel the vehicle, the electrical transmission cable 182 between the power source 180 and the energy storage device 150 may be disconnected.The control system 190 may identify and / or control the amount of electrical energy stored in the energy storage device, which may be referred to as the state of charge (SOC).

[0018] In other embodiments, an electrical transmission cable 182 may be omitted, and electrical energy may be received wirelessly from a power source 180 at the energy storage device 150. For example, the energy storage device 150 may receive electrical energy from the power source 180 via one or more of electromagnetic induction, radio waves, and electromagnetic resonance. Accordingly, it is understood that any suitable approach for recharging the energy storage device 150 from a power source that is not part of the vehicle, such as solar or wind energy, may be used. In this way, the electric motor 120 may propel the vehicle using a different energy source than the fuel used by the engine 110.

[0019] The fuel system 140 may periodically receive fuel from a fuel source located external to the vehicle. As a non-limiting example, the vehicle propulsion system 100 may be fueled by receiving fuel via a fuel dispenser 170, as indicated by arrow 172. In some embodiments, the fuel tank 144 may be configured to store the fuel received from the fuel dispenser 170 until it is delivered to the engine 110 for combustion. In some embodiments, the control system 190 may receive an indication of the level of fuel stored in the fuel tank 144 via a fuel level sensor. The level of fuel stored in the fuel tank 144 (e.g.,as identified by the fuel level sensor), may be communicated to the vehicle operator via, for example, a fuel gauge or an indication on a vehicle instrument panel 196.

[0020] The vehicle propulsion system 100 may also include an ambient temperature / humidity sensor 198 and a roll stability control sensor, such as lateral and / or longitudinal acceleration and / or yaw rate sensor(s) 199. The vehicle instrument panel 196 may include indicator light(s) and / or a text-based display on which messages are displayed to an operator. The vehicle instrument panel 196 may also include various input portions for receiving operator input, such as buttons, touchscreens, voice input / recognition, etc. For example, the vehicle instrument panel 196 may include a refueling button 197 that may be manually actuated or pressed by a vehicle operator to initiate refueling.For example, as described in more detail below, in response to the vehicle operator actuating the refueling button 197, the pressure in a fuel tank in the vehicle may be released so that refueling may be performed.

[0021] In an alternative embodiment, the vehicle instrument panel 196 may communicate audio messages to the operator without display. Further, the sensor(s) 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 the engine output and / or wheel brakes in response to the sensor(s) 199 to increase vehicle stability.

[0022] Fig. 2 shows a schematic representation of a vehicle system 206. The vehicle system 206 includes an internal combustion engine system 208 coupled to an evaporative emissions control system 251 and a fuel system 218. The emissions control system 251 includes a fuel vapor container, such as a fuel vapor canister 222, that can be used to capture and store fuel vapors. In some examples, the vehicle system 206 may be a hybrid electric vehicle system, such as the vehicle propulsion system 100 of Fig. 1.

[0023] The engine system 208 may include an internal combustion engine 210 having a plurality of cylinders 230. In one example, the engine 210 is an embodiment of the engine 110 of Fig. 1. The engine 210 includes an engine intake 223 and an engine exhaust 225. The engine intake 223 includes a throttle 262 fluidly coupled to the engine intake manifold 244 via an intake passage 242. The engine exhaust 225 includes an exhaust manifold 248 leading to an exhaust passage 235 that directs exhaust gas to the atmosphere. The engine exhaust 225 may include one or more emission control devices 270, which may be mounted at a near-engine location in the exhaust. 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 is understood that other components may be included in the engine, such as a variety of valves and sensors.

[0024] A fuel system 218 may include a fuel tank 220 coupled to a fuel pump system 221. In one example, the fuel tank 220 includes the fuel tank 144 of Fig. 1. The fuel pump system 221 may include one or more pumps for pressurizing fuel delivered to the injectors of the engine 210, such as an exemplary injector 266 shown. The fuel pump system 221 may be further configured to deliver fuel to a fuel-fired heater (FOH) system. While a single injector 266 is shown, additional injectors are provided for each cylinder. It is understood that the fuel system 218 may be a no-return fuel system, a return fuel system, or various other types of fuel systems.

[0025] Vapors generated in the fuel system 218 may be routed via a vapor line 231 to the evaporative emission control system 251, which includes the fuel vapor canister 222, before being purged into the engine intake 223. The vapor line 231 may be coupled to the fuel tank 220 via one or more conduits and may include one or more valves for isolating the fuel tank during certain conditions.

[0026] For example, the vapor line 231 may be coupled to the fuel tank 220 via one or more or a combination of the conduits 271, 275 and 276.

[0027] Further, in some examples, one or more fuel tank vent valves may be positioned in conduits 271, 275, or 276. Among other functions, fuel tank vent valves may allow a fuel vapor canister of the emissions control system to be maintained at a low pressure or vacuum without increasing the rate of fuel evaporation from the tank (which would otherwise occur if the fuel tank pressure were lowered). For example, conduit 271 may include a fuel tank isolation valve (FTIV) 252. Conduit 275 may include a relief valve (RV) 285. In one example, conduit 275 is a bypass line, with RV 285 configured to allow vapors to flow to canister 222 when FTIV 252 is closed. Further, in some examples, vapor line 231 may be coupled to a refueling system 219.In some examples, the refueling system 219 may include a fuel cap 205 for sealing the fuel filling system from the atmosphere. The refueling system 219 is coupled to the fuel tank 220 via a fuel filler neck 211.

[0028] Furthermore, the refueling system 219 may include a refueling lock 245. In some embodiments, the refueling lock 245 may be a fuel cap locking mechanism. The fuel cap locking mechanism may be configured to automatically lock the fuel cap 205 in a closed position so that the fuel cap cannot be opened. For example, the fuel cap 205 may remain locked via the refueling lock 245 while the pressure or vacuum in the fuel tank 220 is greater than a threshold. In response to a refueling request, e.g., a request initiated by a vehicle operator via actuation of a refueling button on a vehicle instrument panel (such as the refueling button 197 on the vehicle instrument panel 196 of Fig. 1), the pressure in the fuel tank may be reduced and the fuel cap may be unlocked after the pressure or vacuum in the fuel tank has fallen below a threshold. In this document, unlocking the refueling lock 245 may include unlocking the fuel cap 205. A fuel cap locking mechanism may be a latch or clutch that, when engaged, prevents removal of the fuel cap. The latch or clutch may be locked electrically, for example, by a solenoid, or may be locked mechanically, for example, by a pressure diaphragm.

[0029] In some embodiments, the refueling lock 245 may be a filler tube valve located at an opening of the fuel filler neck 211. In such embodiments, the refueling lock 245 may not prevent removal of the fuel cap 205. Instead, the refueling lock 245 may prevent insertion of a refueling pump into the fuel filler neck 211. The filler tube valve may be electrically locked, for example, by an electromagnet, or may be mechanically locked, for example, by a pressure diaphragm.

[0030] In some embodiments, the refueling lock 245 may be a fuel door lock, such as a latch or clutch that locks a fuel door located in a body panel of the vehicle. The fuel door lock may be electrically locked, for example, by a solenoid, or mechanically locked, for example, by a pressure diaphragm.

[0031] In embodiments where the refueling lock 245 is locked using an electrical mechanism, the refueling lock 245 may be unlocked by commands from the controller 212, for example, when a fuel tank pressure decreases below a pressure threshold. In embodiments where the refueling lock 245 is locked using a mechanical mechanism, the refueling lock 245 may be unlocked via a pressure gradient, for example, when a fuel tank pressure decreases to atmospheric pressure.

[0032] The emissions control system 251 may include one or more fuel vapor canisters 222 (also referred to herein simply as canisters) filled with a suitable adsorbent, the canisters configured to temporarily capture fuel vapors (including evaporated hydrocarbons) generated during fuel tank refill operations and "lost fuel" vapors (i.e., fuel evaporated during vehicle operation). In one example, the adsorbent used is activated carbon. The emissions control system 251 may further 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 emissions 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 routed to a first canister of the more than one canister, then from the first canister to a second canister of the more than one canister, and so on for additional canisters of the one or more canisters. When the canisters are arranged in parallel, a total volume of gases routed through the more than one canister may be routed to the first canister or the second canister, or the total volume of gases may be divided into two volumes, with a first volume of the two volumes routed through the first canister and a second volume of the two volumes routed through the second canister.

[0033] The vent line 227 may also allow fresh air to be drawn into the canister 222 via the vent valve 229 when the stored fuel vapors from the fuel system 218 are purged into the engine intake 223 via a purge line 228 and a purge valve 261. For example, the purge valve 261 may be normally closed but opened under certain conditions (such as certain conditions while the engine is running) so that the vacuum from the engine intake manifold 244 is applied to the fuel vapor canister for purging. In some examples, the vent line 227 may include an optional air filter 259 disposed therein upstream of the canister 222. The flow of air and vapors between the canister 222 and the atmosphere may be regulated by a canister vent valve 229.

[0034] Evaporative emission detection routines may be performed intermittently by controller 212 on fuel system 218 to confirm that the fuel system is not compromised. Therefore, evaporative emission detection routines may be performed using engine-off natural vacuum (EONV), which is generated due to a change in temperature and pressure at the fuel tank following engine shutdown and / or with applied vacuum from a vacuum pump while the engine is off (engine-off leak test). Alternatively, evaporative emission detection routines may be performed while the engine is running by operating a vacuum pump and / or using the vacuum in the engine intake manifold.Tests for undesirable evaporative emissions may be performed by an evaporative leak check module (ELCM) 295 communicatively coupled to the controller 212. The ELCM 295 may be coupled in the vent line 227 between the canister 222 and the vent valve 229. The ELCM 295 may include a vacuum pump configured, in an initial configuration, to apply a negative pressure to the fuel system, such as when performing a leak test. The ELCM 295 may further include a reference orifice and a pressure sensor 296. After vacuum is applied to the fuel system, a change in pressure at the reference orifice (e.g., an absolute change or a rate of change) may be monitored and compared to a threshold. Based on the comparison, undesirable evaporative emissions from the fuel system may be identified.The ELCM vacuum pump may be a reversible vacuum pump and thus configured to apply positive pressure to the fuel system when a lock-up circuit is reversed, thereby placing the pump in a second configuration.

[0035] Canister 222 may include a first buffer 224 surrounding loading port 213. Like canister 222, buffer 224 may include an adsorbent. The volume of buffer 224 may be smaller than (e.g., a fraction of) the volume of canister 222. The adsorbent in buffer 224 may be the same as or different from the adsorbent in the canister (e.g., both may include carbon). Buffer 224 may be positioned within canister 222 such that during loading of the canister through loading port 213, fuel tank vapors are first adsorbed into the buffer and then, when the buffer is saturated, additional fuel tank vapors are adsorbed into the main body of the canister. In contrast, when purging the canister 222 with air drawn in through the vent line 227, fuel vapors can first be desorbed from the canister (e.g.up to a threshold amount) before being desorbed from the buffer. In contrast, when purging the canister 222 with air drawn through the vent line 227, fuel vapors may first be desorbed from the canister (e.g., up to a threshold amount) before being desorbed from the buffer. In other words, the loading and unloading of the buffer 224 are not linear to the loading and unloading of the canister. Therefore, the effect of the canister buffer is to dampen 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 an exhaust pipe.

[0036] The fuel tank 220 is fluidly coupled to the canister 222 via an outlet conduit 276, with the outlet conduit 276 diverging from the fuel tank isolation valve (FTIV) 252, which controls the flow of fuel tank vapors from the fuel tank 220 and through the inlet conduit 271 into the canister 222. By adjusting a position of the FTIV 252, the fuel vapor flow from the fuel tank 220 to the canister 222 can be varied. The FTIV 252 can be actuated to a first open position, coupling the fuel tank 220 to the canister 222 via the conduit 276.In an example where the emissions control system 251 includes more than one canister 222 arranged in parallel, setting the position of the FTIV 252 to a first position may direct the fuel vapor flow from the fuel tank 220 to a first canister, setting it to a second position may direct the fuel vapor flow from the fuel tank 220 to a second canister, and setting it to a third position may direct the fuel vapor flow from the fuel tank 220 to both the first and second canisters. The FTIV may also be actuated to a fourth closed position.

[0037] For example, when the emissions control system 251 includes a canister 222, the FTIV 252 may be actuated to a closed position sealing the fuel tank 220 from the canister 222, with no fuel vapors flowing through the conduit 276. The controller 212 may command an FTIV position based on fuel system conditions, including a vehicle operator request to refuel, fuel tank pressure, and canister loading. In a second example, a 0.03-inch orifice is included in place of the FTIV 252 to restrict vapor flow to the canister.

[0038] In configurations where vehicle system 206 is a hybrid electric vehicle (HEV), fuel tank 220 may be configured as a sealed fuel tank capable of withstanding pressure fluctuations typically encountered during normal vehicle operation and diurnal temperature cycles (e.g., a steel fuel tank). Additionally, the size of canister 222 may be reduced to accommodate the reduced engine operating times in a hybrid vehicle. However, for the same reason, HEVs may also have limited capabilities for fuel vapor canister purging operations.Therefore, the use of a sealed fuel tank with a closed FTIV (also referred to as a non-integrated refueling canister only system (NIRCOS)) prevents daytime and service loss vapors from loading the fuel vapor canister 222 and limits loading of the fuel vapor canister via refueling vapors only. The FTIV 252 may be selectively opened in response to a refueling request to depressurize the fuel tank 220 before fuel can be received into the fuel tank via the fuel filler neck 211. In particular, when the emissions control system 251 includes a canister 222, the FTIV 252 may be actuated to the first open position to depressurize the fuel tank via the first conduit 276 and the canister loading port 213 to the canister.

[0039] In some embodiments (not shown), a pressure control valve (PCV) (e.g., RV 285) may be configured in a conduit coupling the fuel tank 220 to the canister 222 in parallel with the conduit 276. If included, the RV may be controlled by the powertrain control module (e.g., controller 212) using a pulse-width modulation cycle to relieve any excess pressure generated in the fuel tank, such as when the internal combustion engine is running. Additionally or optionally, the RV may be pulse-width modulated to vent excess pressure from the fuel tank when the vehicle is operating in electric vehicle mode, for example, in the case of a hybrid electric vehicle.

[0040] When transitioned to a second (open) position for the emissions control system 251 having a canister 222, the FTIV 252 allows fuel vapors from the fuel tank 220 to be vented to the canister 222. The second open position may be a fully open position and the first open position may be a partially open position, e.g., half open.

[0041] For the emissions control system 251 having at least one canister 222, including more than one canister 222 arranged in parallel, fuel vapors may be stored in the canister 222 while air purged of the fuel vapors is vented to the atmosphere via the canister vent valve 229. The stored fuel vapors in the canister 222 may be purged to the engine intake 223 via the purge valve 261 when engine conditions permit. The refueling lock 245 may be unlocked to allow a fuel cap to be opened only after the fuel tank pressure has been sufficiently reduced, such as below the second threshold pressure.

[0042] The RV 285 may open during conditions where the fuel tank pressure exceeds a threshold fuel tank pressure without input from the controller 212. This may occur during conditions where the controller 212 is inactive, which may occur when the engine is off and / or when the vehicle is off. Venting events when the controller 212 is inactive may not be tracked in prior art examples, resulting in insufficient canister purges, which may cause vapors to be released into the atmosphere. This may be further exacerbated in hybrid vehicles where the internal combustion engine may be 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. The FOH system is controlled with respect to Fig. 3. The FOH system may be operated to flow heated air to the canister 222, which may release vapors therefrom under desired conditions.

[0043] The vehicle system 206 may further include a control system 214 (such as the control system 190 of Fig. 1). 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 an exhaust gas sensor 237 located upstream of the emissions control device, an exhaust gas temperature or pressure sensor 233, a fuel tank pressure transducer (FTPT) or pressure sensor 291, a canister load sensor 243, and an ELCM pressure sensor 296. Therefore, pressure sensor 291 provides an estimate of fuel system pressure. In one example, fuel system pressure is a fuel tank pressure, e.g., in 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 the fuel injector 266, the throttle 262, the FTIV 252, the refueling interlock 245, the canister vent valve 229, and the purge valve 261. The control system 214 may include a controller 212. The controller may receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on an instruction or code programmed therein corresponding to one or more routines. The controller 212 receives signals from the various sensors from the . Fig. 1-2 and sets the different actuators from the Fig. 1-2 to adjust the motor operation based on the received signals and instructions stored in a memory of the controller.

[0044] For example, in response to a vehicle operator's refueling request, the controller may retrieve a sensor input from the fuel tank pressure transducer (FTPT) 291 and compare it to a threshold. If the pressure is higher than the threshold, the controller may send a signal commanding the FTIV 252 to a position that accelerates the depressurization of the fuel tank. In doing so, the controller 212 may adjust the position of the FTIV 252 to depressurize fuel vapors toward the loading port 213 of the canister 222 based on the canister load, as estimated via sensor 243, and / or an estimated time for depressurization of the fuel tank.Once the pressure of the fuel tank has been sufficiently reduced, as inferred based on the output of the fuel tank pressure sensor, the controller may send a signal commanding opening or release of the refueling lock 245 so that fuel may be received into the fuel tank 220 via the fuel filler neck 211.

[0045] With reference to Fig. 3 shows a FOH system 300. The FOH system 300 may be fluidly coupled to the evaporative emission control system 251 via the first passage 302 and the second passage 304. In one example, the first passage 302 is an inlet passage and the second passage 304 is an outlet passage. The first passage 302 may intersect the purge line 228 at a junction between the canister 222 and the purge valve 261 at a first outermost end. The first passage 302 may intersect an FOH inlet passage 306 at a location upstream of an FOH 310 relative to a gas flow direction. A first valve 303 may be disposed in the first passage 302 and configured to control vapor flow from the canister 222 to the FOH inlet passage 306.The first valve 303 may be adjusted to a fully closed position, a fully open position, or any position in between based on desorption of vapors from the canister 222. Additionally or alternatively, the position of the first valve 303 may be adjusted based on engine operation.

[0046] The FOH 310 may be configured to combust fuel. When combusting fuel, the FOH 310 may heat air. The heated air may be expelled through a FOH outlet 312. Combustion gases may be expelled from the FOH 310 via an exhaust outlet 314 separate from the FOH outlet. The exhaust outlet 314 may direct combustion gases directly to the atmosphere. In one example, the exhaust outlet 314 may additionally or alternatively direct combustion gases to the engine exhaust 225. Fig. 2. The combustion gases of the FOH 310 do not mix with the ambient air or the heated air flowing through it. In one example, the FOH 310 may include at least one combustion chamber 311 with an ignition device 313. Fuel and air may be supplied to the combustion chamber 311, with air flowing outside and around the at least one combustion chamber 311. The combustion chamber 311 may be hermetically sealed from passages in which ambient air and heated air flow through the FOH 310. The FOH 310 may supply fuel via a fuel pump (e.g., the fuel pump 221 of Fig. 2 or a separate fuel pump). Additionally or alternatively, fuel vapors 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 the air provided by the clean air inlet is heated and does not mix with fuel vapor or liquid fuel. In one example, the clean air inlet may be a single continuous passage with FOH outlet 312, where portions of the passage may twist or extend proximally to cylinder 311. The air may be heated as a result of combustion, with the heated air being directed to FOH outlet 312.

[0047] A cabin heating valve 316 may be disposed in the FOH outlet 312 at a location downstream of a junction between the FOH outlet 312 and the second passage 304. The cabin heating valve 316 may be adjusted to a fully closed position, a fully open position, or any position in between based on a cabin heating request. The position of the cabin heating valve 316 may be further adjusted based on engine operation in combination with the cabin heating request. In one example, the cabin heating valve may control the flow of heated air to a vehicle cabin interior.

[0048] A second valve 305 may be disposed in the second passage 304. The second valve 305 is configured to control the flow of heated air from the FOH outlet 312 to a junction between the second passage 304 and the vent line 227. In one example, the second passage 304 intersects the vent line 227 at a location between the canister 222 and the ELCM 295 at a first extreme end. A second extreme end of the second passage 304, opposite the first extreme end, intersects the FOH outlet 312 at a junction between the FOH 310 and the cabin heater valve 316. In one example, the second valve 305 is a check valve configured to open in the presence of heated air entering the second passage 304 from the FOH outlet 312. In such an example, the second valve 305 may be thermostatically controlled via a wax or similar element.Additionally or alternatively, the second valve 305 may be controlled by a controller and configured to move to a fully closed position, a fully open position, or any position therebetween.

[0049] The Fig. The arrows included in Figure 3 indicate a direction in which gases may flow during various conditions of the FOH system 300 and the evaporative emission control system 251. The positions of the purge valve 261, the first valve 303, the second valve 305, and the cabin heater valve 316 may be adjusted based on a condition of at least the canister 222. The methods of Fig. 4 and Fig. 5 illustrates operations for releasing vapors from canister 222 via heated air from FOH 310 during engine-off conditions to control vapor emissions from and loading of canister 222. This may reduce vehicle emissions. The vapors released by canister 222 may be stored in cylinders of the engine prior to engine start and / or consumed by FOH 310 as it heats air.

[0050] With reference to Fig. 4, this shows a method 400 for flowing heated air via the FOH to the canister. The canister vapors flow to the engine cylinders and are stored therein prior to an engine restart. Instructions for performing method 400 and the other methods included herein may be provided by a controller based on instructions stored in a memory of the controller and in conjunction with signals received from sensors of the internal combustion engine system, such as those described above with respect to Fig. 1-3. The controller may use engine actuators of the engine system to adjust engine operation according to the methods described below.

[0051] Method 400 begins at 402, which includes determining current operating parameters. Current operating parameters may include, among others, one or more of manifold vacuum, engine speed, engine temperature, vehicle speed, and air-fuel ratio.

[0052] At 404, method 400 may include determining an ambient temperature. The ambient temperature may be determined via a temperature sensor mounted on the vehicle. The temperature sensor may be distal to other heat-emitting devices so that heat released by other vehicle components cannot affect a temperature reading from the temperature sensor. Additionally or alternatively, the ambient temperature may be provided by a weather service via a wireless connection. In some examples, a mobile device may provide the ambient temperature via a wireless connection. The ambient temperature may further be based on sunlight, wind, ground surface, rain, and the like. For example, direct sunlight may increase the ambient temperature reading.Additionally or alternatively, the ambient temperature reading may be elevated when the ground surface is asphalt compared to when the ground surface is dirt when a relatively large amount of sunlight is directed onto the vehicle.

[0053] At 406, method 400 may include determining whether an ambient temperature is less than a certain ambient temperature. The certain 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 treat the canister vapors due to ambient temperatures that are higher than or equal to the certain ambient temperature. If the ambient temperature is not less than the certain ambient temperature, method 400 may proceed to 502 in Fig. Skip to 5.

[0054] If the ambient temperature is less than the determined ambient temperature, method 400 may include determining at 408 whether a canister purge is requested during an engine-off event. In one example, the engine may be off 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, method 400 may include not turning on the FOH at 410.

[0055] If a canister purge is requested and the engine is off, method 400 may begin at 412 opening the canister purge valve (CPV), such as purge valve 261 of Fig. 2. This allows vapors from the canister to flow to the engine via the purge line and the open CPV.

[0056] At 414, method 400 may include turning on the FOH and opening the second valve. Thus, the FOH may heat air, and the second valve may direct the heated air to the canister. The heated air may assist in releasing vapors from the canister. Fuel from a fuel tank may be provided to the FOH via a pump, and combustion may be initiated therein.

[0057] At 416, method 400 may include adjusting a cabin heating valve position based on a cabin heating request. The cabin heating valve may be moved to a more open position as the cabin heating request increases.

[0058] In one example, a tune, such as fueling or mass air flow, of the FOH may be adjusted based on one or more of the cabin heating request, an estimate of the engine off duration, and a canister load. For example, the FOH fueling may increase in response to one or more of the cabin heating request increasing, the estimate of the engine off duration decreasing, and / or the canister load being relatively high. The canister load may be relatively high if it is above a threshold canister load. Additionally or alternatively, the canister load may impact a desorption rate, where the desorption rate may increase if the canister load is relatively high. The estimate of the engine off duration may be based on a driver's driving behavior, a time of day, traffic conditions, a vehicle location, and the like.For example, when the driver stops at a traffic light, the duration of the stop can be learned based on previous stops at a similar time of day and under similar traffic conditions.

[0059] In a real-world example, the FOH can be operated at a relatively high temperature with a relatively high amount of air and fuel if the canister load is above the threshold canister load and the engine-off duration estimate is relatively short. In contrast, the FOH can be operated at a relatively low temperature with a relatively low amount of air and / or fuel if the canister load is below the threshold canister load and / or the engine-off duration estimate is relatively long.

[0060] At 418, method 400 optionally includes 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 first passage may not be included in the FOH system. However, the first valve and 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 flowing from the canister to the FOH. In one example, the first valve may be closed if an engine restart is scheduled to occur following the purge event of method 400. Thus, the vapors may be used for combustion in the engine to promote vehicle propulsion.

[0061] If the engine restart is not planned, the vapors can be directed to the FOH in a closed-loop operation. The CPV can be closed and the first valve can be opened to allow vapors desorbed from the canister to flow to the FOH. Closed-loop operation is described in relation to Fig. 5 described in more detail.

[0062] In some examples, vapors from the canister may be routed in addition to or alternatively to each of the engine and the FOH. The CPV and the first valve may be moved to partially open positions to promote 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 previous engine restart events following the purge event. For example, if engine knock or another condition occurs during engine restart, more or fewer vapors may be routed to the FOH.

[0063] 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 through the second passage to the canister. The heated air may release vapors from the canister.

[0064] At 422, method 400 may include flowing canister vapors into the engine cylinders. In one example, the intake valves of the engine cylinders are open and the exhaust valves of the engine cylinders are closed. In this way, vapors may be stored in the engine cylinders and consumed upon engine restart. Fueling parameters may be adjusted during engine restart to account for the fuel vapors stored therein. Thus, in one example, upon engine restart following an engine stop, fueling to the engine may be adjusted based on one or more of a canister vapor loading, a desorption rate, a FOH fueling, a cabin heating request, and a second valve position. For example, fueling to the engine may be decreased upon engine restart in response to FOH fueling increasing.Additionally or alternatively, the fuel supply to the engine may decrease upon engine restart in response to the canister vapor load decreasing to account for the presence of canister vapors in the engine. The FOH may be shut off upon engine restart.

[0065] With reference to Fig. 5, this shows a method 500 for consuming vapors from the canister via the FOH when a breakthrough may occur. The method 500 begins at 502 after a "no" at 406 in Fig. 4. Therefore, the ambient temperature is above the determined ambient temperature, and at 502, method 500 includes determining whether a canister breakthrough probability is greater than a threshold probability. The canister breakthrough probability may be based on a combination of the ambient temperature, the canister loading, and a period of time the engine was off. For example, the canister breakthrough probability increases as the ambient temperature increases and / or as the canister loading increases and / or as the period of time the engine is off (e.g., engine off duration) increases. The threshold probability may be based on a percentage, such as a 50%, 70%, or 90% probability, that vapors may escape from the canister. In one example, a relative canister loading may be determined based on a combination of a canister loading and the ambient temperature.If the canister breakthrough probability is not greater than the threshold probability, method 500 may include, at 504, not flowing the canister vapors to the FOH. Thus, the FOH may not be enabled.

[0066] If the canister breakthrough probability is greater than the threshold probability, method 500 may include determining at 506 whether the engine is off. The engine may be off during start / stop or electric-only operation of the vehicle. Additionally or alternatively, the engine may be off if the vehicle is turned off in response to the vehicle operator depressing an ignition button and / or removing an ignition key. If the engine is not off, method 500 proceeds to 504, as described above. The FOH may not be used to consume canister vapors or promote vapor desorption when the engine is on.

[0067] If the engine is off, method 500 may include turning on the FOH at 508. Turning on the FOH may include flowing fuel and air to the at least one cylinder of the FOH. Fuel may be provided from the fuel tank via a pump. Combustion may occur within the FOH, which may be used to heat air.

[0068] At 510, method 500 may include opening the first valve. Thus, the first passage may allow gases from the purge line to flow into the inlet of the FOH.

[0069] At 512, method 500 may include opening the second valve. Heated air from the FOH may be directed to the canister, which may force the vapors to be released therefrom.

[0070] At 514, the method 500 may include closing the CPV. Vapors from the canister are prevented from flowing to an intake of the engine.

[0071] At 516, method 500 may include switching the ELCM to a pressure mode. The pressure mode may be used to control a temperature of heated air flowing to the canister. Additionally or alternatively, a switching valve in the ELCM may be used to control the temperature.

[0072] At 518, method 500 may include flowing vapors from the canister to the FOH. The vapors may flow into the FOH's combustion chamber and combust. Thus, the vapors may be consumed so that no unburned hydrocarbons are released into the atmosphere. In one example, fueling of the FOH may be adjusted based on a desorption rate of the canister. For example, as the desorption rate increases, fueling of the FOH may be reduced to account for more vapors flowing to the FOH compared to a lower desorption rate.

[0073] 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 promote the release of vapors from the canister's adsorbent. The FOH may remain on until the engine is turned on, the vehicle is turned off, the canister load decreases below a lower limit, and / or the ambient temperature drops below the threshold ambient temperature.

[0074] With reference to Fig.6 graphically illustrates an operating sequence via trace 600, which illustrates changes to conditions of the FOH system and the evaporative emission control system when the canister is being cleaned (e.g., vapors are removed therefrom). Trace 610 illustrates whether the FOH is on or off. Trace 620 illustrates an ambient temperature. Trace 630 illustrates a canister load, and dashed line 632 illustrates a threshold canister load. Trace 640 illustrates whether the engine is on or off. Before t1, the engine and FOH are off. The ambient temperature increases to a relatively high value, causing an increase in a relative canister load. The relative canister load may take into account an actual canister load and the ambient temperature.In one example, the actual canister load is determined via a hydrocarbon sensor mounted on a canister port. Additionally or alternatively, the actual canister load may be estimated based on an engine operating period and / or a front of house operating period.

[0075] At t1, the relative canister load is equal to the threshold canister load. The FOH is turned on. Between t1 and t2, the FOH begins to heat air and direct the heated air to the canister. The relative canister load decreases as vapors from it are directed to the FOH. The FOH can combust the vapors in combination with fuel discharged from the vehicle's fuel tank.

[0076] At t2, the relative canister load is relatively low and less than the threshold canister load. Thus, the FOH is shut down and no longer consumes fuel or heats air. After t2, the canister load begins to increase because the engine remains off.

[0077] The disclosure supports a method that includes heating air using a fuel-fired 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 further includes directing vapors from the canister to the FOH. A second example of the method, optionally including the first example, further includes the FOH combusting the vapors. A third example of the method, optionally including one or more of the preceding examples, further includes using the FOH further comprising shutting down an engine. A fourth example of the method, optionally including one or more of the preceding examples, further 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 preceding examples, further includes directing vapors from the canister to an engine, wherein intake valves of the engine are open and exhaust valves of the engine are closed.

[0078] The disclosure also supports a system including an internal combustion engine, an evaporative emissions control system including a canister, a fuel tank, and a fuel-fired heater (FOH) fluidly coupled to the canister. A first example of the system further includes a controller having computer-readable instructions stored on 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. A second example of the system, optionally including the first example, further includes the instructions further causing the controller to close a first valve in a first passage and open a canister purge valve to allow vapors from the canister to flow only to the engine.A third example of the system, optionally including one or more of the preceding examples, further includes where the instructions further cause the controller to adjust fueling of the engine upon an engine restart following the purge event based on one or more of a fueling of the FOH and a cabin heating request during the purge event. A fourth example of the system, optionally including one or more of the preceding examples, further includes a controller having computer-readable instructions stored on a non-transitory memory thereof, which, when executed, enable the controller to flow heated air from the FOH to the canister in response to an ambient temperature being greater than a threshold temperature.A fifth example of the system, optionally including one or more of the preceding examples, further includes where the instructions further cause the controller to adjust a position of a first valve in a first passage to allow vapors to flow from the canister to the FOH, and where 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. A sixth example of the system, optionally including one or more of the preceding examples, further includes where the instructions further cause the controller to adjust fueling of the FOH based on one or more of an engine stop duration, a canister load, the ambient temperature, and a canister desorption rate.A seventh example of the system, optionally including one or more of the preceding examples, further includes the FOH being 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 the first passage comprising a first valve configured to control an amount of vapor flowing to the FOH.

[0079] The disclosure further supports a method including supplying fuel to a fuel-fired heater (FOH) and directing heated air from the FOH to a canister disposed in an evaporative emission control system. A first example of the method further includes flowing vapors from the canister to the FOH via a purge line and a first passage, wherein fueling of the FOH is adjusted based on a desorption rate of the canister. A second example of the method, optionally including the first example, further includes flowing vapors from the canister to an engine via a purge line, further comprising adjusting fueling of the engine upon engine restart based on one or more of the FOH fueling and a desorption rate of the canister.A third example of the method, optionally including one or more of the preceding examples, further includes fluidly coupling each of the canister and the FOH to a fuel tank. A fourth example of the method, optionally including one or more of the preceding examples, further includes adjusting the fuel supply to the FOH based on a cabin heating request.

[0080] It should be noted that the exemplary control and estimation routines included in this document may be used with various engine and / or vehicle system configurations. The control methods and routines disclosed in this document may be stored as executable instructions in non-transitory memory and may be executed by the control system including the controller in combination with the various sensors, actuators, and other internal combustion engine hardware. The specific routines described in this document may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Accordingly, various illustrated acts, operations, and / or functions may be performed in the illustrated sequence or in parallel, or in some cases, may be omitted.Likewise, the processing order 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. One or more of the illustrated acts, operations, and / or functions may be performed repeatedly depending on the particular strategy employed. Further, the described acts, operations, and / or functions may graphically represent code to be programmed into non-transitory memory of the computer-readable storage medium in the internal combustion engine control system, wherein the described acts are performed by executing the instructions in a system including the various internal combustion engine hardware components in combination with the electronic controller.

[0081] It is understood that the configurations and routines disclosed in this document are exemplary in nature and that these specific embodiments are not to be considered limiting, as numerous variations are possible. For example, the above technology may be applied to V6, I4, I6, V12, horizontally opposed 4-cylinder, and other internal combustion engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various systems and configurations, as well as other features, functions, and / or characteristics disclosed in this document.

[0082] In this context, the term “approximately” is intended to mean plus or minus five percent of the range, unless otherwise specified.

[0083] The following claims specifically point out specific combinations and subcombinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be construed as including the inclusion of one or more such elements and 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 amending the present claims or by filing new claims in this or a related application.Such claims, whether broader, narrower, equal, or different in scope than the original claims, are also considered to be included within the subject matter of the present disclosure.

[0084] According to the present invention, a method includes heating air using a fuel-fired heater (FOH); and directing the heated air from the FOH to a canister in an evaporative emission control system. In one aspect of the invention, the method includes directing vapors from the canister to the FOH.

[0085] In one aspect of the invention, the FOH combusts the vapors.

[0086] In one aspect of the invention, using the FOH further comprises shutting down an internal combustion engine.

[0087] In one aspect of the invention, the method includes directing heated air from the FOH to a vehicle cabin interior.

[0088] In one aspect of the invention, the method includes directing vapors from the canister to an internal combustion engine with intake valves of the engine open and exhaust valves of the engine closed.

[0089] According to the present invention, a system is provided comprising: an internal combustion engine; an evaporative emission control system including a canister; a fuel tank; and a fuel-fired heater (FOH) fluidly coupled to the canister.

[0090] According to one embodiment, the invention is further characterized by 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.

[0091] In one 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 from the canister to flow only to the engine.

[0092] According to one embodiment, the instructions further cause the controller to adjust engine fueling upon engine restart following the purge event based on one or more of a FOH fueling and a cabin heating request during the purge event.

[0093] According to one embodiment, the invention is further characterized by 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 in response to an ambient temperature being greater than a threshold temperature.

[0094] According to one embodiment, the instructions further cause the controller to adjust a position of a first valve in a first passage to allow vapors 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.

[0095] According to one embodiment, the instructions further cause the controller to adjust fueling of the FOH based on one or more of an engine stop duration, a canister load, the ambient temperature, and a canister desorption rate.

[0096] According to one 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.

[0097] According to one embodiment, the first passage comprises a first valve configured to control an amount of steam flowing to the FOH.

[0098] According to the present invention, a method includes: supplying fuel to a fuel-fired heater (FOH); and directing heated air from the FOH to a canister in an evaporative emission control system.

[0099] In one aspect of the invention, the method includes flowing vapors from the canister to the FOH via a purge line and a first passage, wherein fueling of the FOH is adjusted based on a desorption rate of the canister.

[0100] In one aspect of the invention, the method includes flowing vapors from the canister to an engine via a purge line, further comprising adjusting a fueling of the engine upon engine restart based on one or more of the FOH fueling and a desorption rate of the canister.

[0101] In one aspect of the invention, each of the canister and the FOH is fluidly coupled to a fuel tank.

[0102] In one aspect of the invention, the fuel supply to the FOH is adjusted based on a cabin heating request.

Claims

[1] Procedure comprising: Heating air using a fuel-fired heater (FOH); and Directing heated air from the FOH to a canister in an evaporative emission control system. [2] The method of claim 1, further comprising directing vapors from the canister to the FOH. [3] The method of claim 2, wherein the FOH combusts the vapors. [4] The method of claim 1, wherein using the FOH further comprises shutting down an internal combustion 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 internal combustion engine, wherein intake valves of the engine are open and exhaust valves of the engine are closed. [7] System comprising: an internal combustion engine; an evaporative emission control system comprising a canister: a fuel tank; and a fuel-fired heater (FOH) fluid-coupled to the canister. [8] The system of claim 7, further comprising 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. [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 flow vapors from the canister only to the engine. [10] The system of claim 8, wherein the instructions further cause the controller to adjust engine fueling upon engine restart following the purge event based on one or more of a FOH fueling and a cabin heating request during the purge event. [11] The system of claim 7, further comprising 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 in response to an ambient temperature being greater than 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 vapors 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 an engine stop duration, a canister load, the ambient temperature, and a canister desorption rate. [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 steam flowing to the FOH.

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